Winter Blitz Continues Across The Area for Day #5

 ...Pertinent Weather Information...

Occasional periods of freezing drizzle, snow flurries, sleet, and/or light snow will continue through about 3-4pm, then diminish through 6pm. Any ice accumulation will likely average a trace or other small amount generally less than 0.1 inch. Any sleet and/or snow accumulation will likely average a trace or other small amount generally less than 0.5 inch.

Air temperatures are expected to remain below freezing again today, and gusty winds will produce wind chill values mainly in the teens. Temperatures will finally rise above freezing for approximately 4-5 hours on Friday afternoon, then fall into the mid to upper teens on Saturday morning.

...Direct, Weather Related Impacts...

Any melt of ice/snow that occured due to partial sunshine on Wednesday has refrozen overinght. Patchy, generally trace amounts of new ice accumulations from patchy freezing drizzle have also occurred overnight and will continue possible into early this morning, making road conditions hazardous again even in areas that saw some improvement yesterday afternoon.

During the day today, patchy freezing drizzle, snow flurries, sleet and/or light snow are possible at times. The occasional light freezing precipitation along with the presence of cloud cover and sub-freezing temperatures throughout the day will likely hamper the melting efforts today, with hazardous road conditions likely to continue in many areas.

...Ongoing Infrastructure Issues...

The refreeze of any partially melted ice/snow overnight along with ice remaining on tree limbs and power lines coupled with gusty winds have maintained the already severely stressed (and in some cases, damaged) infrastructure situation across many parts of the area. Due to this and the other reasons outlined above, it is quite possible that some parts of the area will remain without power, or only sporadically have power, for a number of additional days as a result. Water supplies also remain compromised in many parts of the area due to 1) electrical failure at pumping stations and/or 2) failure of back up generators after the main power supply failed. Those water supplies that still exist are typically producing lower than normal pressure, and boil water notices are in effect for most of the area. These conditions are likely to continue until 1) consistently reliable power is restored area wide, and 2) the pumping stations, once back online, are able to sufficiently build pressure.

After falling into the middle to upper teens tonight/early Friday morning, temperatures will finally begin to moderate across the area during the day on Friday, likely rising above freezing for 4-5 hours during the afternoon. This should lead to more rapidly improving road and surface conditions, which hopefully will lead to improved ability for infrastructure to be restored. The milder temperatures will also decrease the demand on the electric and gas supplies, which should help rebuild capacity to normal levels over time. Readings will fall back into the upper teens on Friday night/early Saturday, causing a refreeze of melted ice/snow on untreated surfaces once again on Saturday morning, but by Saturday afternoon readings will be well into the 40s. Present indicaitons suggest that, after about 10am on Saturday, temperatures will not go back below freezing again within the remainder of the 7 day period.

We will continue monitoring the situation and issue updates as conditions warrant.

Another Significant Round of Ice Likely Tonight into Wednesday Morning....

...Discussion...

Freezing drizzle is expected to develop around 9pm this evening, increase to periods of freezing rain around Midnight tonight and continue through about 9am on Wednesday morning. The freezing rain may fall heavily at times tonight into early Wednesday morning.

Ice accumulation of 0.1-0.2 inch is likely area-wide with up to 0.25 inch possible in some spots. Additional layers of ice on top of the existing snow and ice pack will maintain, if not increase, treacherous conditions across the area through at least Wednesday afternoon and possibly beyond. Additionally, new layers of ice on top of the existing snow and ice pack will continue to make power, heat and water restoration difficult at best for at least the next 24-36 hours.

Any additional ice accumulation, regardless of the amount, taking place on an already stressed (and in some cases, damaged) infrastructure will obviously be quite problematic. It is quite possible that some parts of the area will remain without power, or only sporadically have power, for a number of days as a result. Water supplies have also become compromised in many parts of the area due to 1) electrical failure at pumping stations and/or 2) failure of back up generators after the main power supply failed. Those water supplies that still exist are typically producing lower than normal pressure, and boil water notices are in effect as a result for many parts of the area.

...Summary...

In summary, we do not expect to see conditions, with regard to direct weather impacts, begin to improve until Wednesday afternoon. Even then, widespread impacts to electric, natural gas and water supplies will continue, possibly for days in some parts of the area.

Significant Ice Event Appears Probable for Tuesday night/Wednesday Morning...

 Expected impacts:

• Freezing drizzle and then freezing rain are expected to develop around 10pm on Tuesday evening and continue at times through about 12 Noon on Wednesday
• The freezing rain may fall heavily at times on Tuesday night and Wednesday morning
• The precipitation may mix with sleet at times, especially within the last few hours of the event
• Present indications suggest that ice accumulation of 0.1-0.25 inch is probable across much of the area with this event
• The combination of this event with what will likely be continuing impacts from the event of today through Monday morning will create a particularly hazardous situation across the area for much of this week

Discussion:

Freezing drizzle and then freezing rain are expected to develop around 10pm on Tuesday evening and continue at times through about 12 Noon on Wednesday. The freezing rain may fall heavily at times on Tuesday night and Wednesday morning. The precipitation may mix with sleet at times, especially within the last few hours of the event, but the majority of the precipitation will fall as freezing drizzle and freezing rain based on present indications.

Present indications suggest that ice accumulation of 0.1-0.25 inch is probable across much of the area with this event. The combination of this event with what will likely be continuing impacts from the event of today through Monday morning will create a particularly hazardous situation across the area for much of this week.

As this event will occur shortly after the significant weather event of today through Monday morning, any additional ice accumulation taking place on an already stressed (and in some cases, damaged) infrastructure would obviously be quite problematic. Additionally, temperatures will remain below freezing through at least Wednesday afternoon, meaning that accumulated ice and/or snow from the today/Monday storm will still be in place across much of the area when the event of Tuesday night and Wednesday morning begins.

It is possible that some parts of the area will be without power for a number of days, due to the combined impacts of the today/Monday storm and the Tuesday night/Wednesday storm, and with temperatures well below freezing throughout which will hamper restoration efforts in some cases.

Major Winter Weather Event to Unfold Today into Tonight/Early Monday, with Some Impacts to Linger for Days....

 Expected impacts:

• Occasional freezing drizzle, occasional light freezing rain and/or sleet will continue at times through about 12 Noon today with ice and/or sleet accumulation of less than 0.1 inch
• Freezing rain and sleet will increase between 12 Noon and 3pm, becoming widespread by 6pm and continue through about Midnight tonight, then change to snow and continue through about 6am Monday
• Ice accumulation of around 0.1 inch is expected for most of the area with 0.1-0.2 inch possible in some spots mainly from 12 Noon today through 6pm today
• Sleet accumulation of around 0.5 inch is expected for most of the area with 0.5-1.0 inch possible in some spots mainly from 3pm today to Midnight tonight
• Snow accumulation of 2-3 inches is expected for most of the area with 4-5 inches possible in some spots mainly from Midnight tonight to 6am Monday

Discussion:

...Now through 12 Noon Today...
Freezing drizzle and occasional periods of light freezing rain and/or sleet will continue at times through about 12 Noon today. Overall, the precipitation will be very light in intensity during this period. It should also be noted, as a result, that much of the precipitation during this time period will be too light to be detected with weather radar.

Ice accumulation of less than 0.1 inch is expected for most of the area throughout the period.

...12 Noon Today through 6am Monday...
Freezing rain and sleet will increase between 12 Noon and 3pm today, becoming widespread by 6pm today and continuing through about Midnight tonight. The freezing rain and sleet may fall heavily at times this afternoon and especially this evening, resulting in rapidly deteriorating conditions across most of the area.

The wintry mix will change to snow around Midnight tonight and continue through about 6am on Monday. The snow may fall heavily at times during this time period.

Ice accumulation of around 0.1 inch is expected for most of the area with 0.1-0.2 inch possible in some spots mainly from 12 Noon to 6pm today.

Sleet accumulation of around 0.5 inch is expected for most of the area with 0.5-1.0 inch possible in some spots mainly from 3pm today to Midnight tonight.

Snow accumulation of 2-3 inches is expected for most of the area with 4-5 inches possible in some spots mainly from Midnight tonight to 6am Monday.

...Expected Impacts...
For the lighter rounds of precipitation this morning, the primary concerns will be light glazed icing on bridges, overpasses, metallic and other colder/elevated surfaces. This will create hazardous travel conditions at times, especially on the flyovers and other elevated roadways across the area (similar to what we would typically see with a "freezing drizzle" type event).

The increase in freezing rain and sleet this afternoon and evening will result in the rapid deterioration of road and other conditions across the area. Many roadways are likely to become impassable, and travel is highly discouraged. Elevated roadways will deteriorate first, followed by secondary roadways and then many primary roadways across the area.

Northerly winds of 15-25 mph with gusts of 30-35 mph may create areas of blowing snow at times, especially in more open areas with a direct exposure to a Northerly wind tonight into early on Monday morning. Additionally, what is likely to be the presence of accumulated ice/sleet followed by accumulated snow combined with the gusty winds may result in the downing of tree limbs and power lines in at least some parts of the area, which will increase the risk of power outages in the affected areas.

Temperatures will remain well below freezing following the event, bottoming out in the single digits early on Tuesday morning, and not rising above freezing (and then briefly) until after 12 Noon on Wednesday. This means that the accumulated ice/snow will remain across the area from Monday through at least Wednesday, which could further hamper efforts to restore power to areas with outages from the storm. As a result of this, we highly recommend that preparations include making sure to have an alternate heating source should your primary source fail as a result of the storm and/or the cold temperatures creating demand that some gas/electric companies cannot fully meet.

...Additional Information Concerning Next Week...
Another round of wintry precipitation is expected from late Tuesday evening through Wednesday morning. Please refer to the latest updates pertaining to that time period for additional details.

Several Rounds of Wintry Precip Likely through Monday Morning

 Expected impacts:

• Freezing drizzle and occasional light freezing rain or sleet will continue at times through about 12 Noon on Sunday with ice and/or sleet accumulation of generally less than 0.1 inch
• Freezing rain and sleet will increase around 12 Noon on Sunday and continue through about 3-4am Monday, then change mostly to snow and continue through about 9am Monday
• Ice accumulation of around 0.1 inch is expected for most of the area with 0.1-0.2 inch possible in some spots mainly from 12 Noon Sunday to 9pm Sunday
• Sleet accumulation of around 0.5 inch is expected for most of the area with 0.5-1.0 inch possible in some spots mainly from 6pm Sunday to 4am Monday
• Snow accumulation of 1-2 inches is expected for most of the area with 2-3 inches possible in some spots mainly from 4am Monday to 9am Monday

Discussion:

...Now through 12 Noon Sunday...
Freezing drizzle and occasional periods of light freezing rain and/or sleet will continue at times through about 12 Noon on Sunday. There may be a brief uptick in the activity at times from around 6pm today to around Midnight tonight, otherwise, the majority of the activity is expected to generally be light and spotty during the period.

Ice accumulation of generally less than 0.1 inch is expected for most of the area throughout the period.

...12 Noon Sunday through 9am Monday...
Freezing rain and sleet will increase around 12 Noon on Sunday and continue through about 3-4am Monday. The freezing rain and sleet may fall heavily at times on Sunday afternoon and especially on Sunday evening, resulting in rapidly deteriorating conditions across most of the area.

The wintry mix will change mostly to snow around 3-4am on Monday and continue through about 9am Monday. The snow may fall heavily at times during this time period, especially right around dawn on Monday morning.

Ice accumulation of around 0.1 inch is expected for most of the area with 0.1-0.2 inch possible in some spots mainly from 12 Noon Sunday to 9pm Sunday.

Sleet accumulation of around 0.5 inch is expected for most of the area with 0.5-1.0 inch possible in some spots mainly from 6pm Sunday to 4am Monday.

Snow accumulation of 1-2 inches is expected for most of the area with 2-3 inches possible in some spots mainly from 4am Monday to 9am Monday.

...Expected Impacts...
For the lighter rounds of precipitation today, tonight and Sunday morning, the primary concerns will be light glazed icing on bridges, overpasses, metallic and other colder/elevated surfaces. This will create hazardous travel conditions at times, especially on the flyovers and other elevated roadways across the area (similar to what we would typically see with a "freezing drizzle" type event).

The increase in freezing rain and sleet on Sunday afternoon and evening will result in the rapid deterioration of road and other conditions across the area. Many roadways are likely to become impassable, and travel is highly discouraged. Elevated roadways will deteriorate first, followed by secondary roadways and then many primary roadways across the area.

Northerly winds of 15-25 mph with gusts of 30-35 mph may create areas of blowing snow at times, especially in more open areas with a direct exposure to a Northerly wind early on Monday morning. Additionally, what is likely to be the presence of accumulated ice followed by accumulated snow combined with the gusty winds may result in the downing of tree limbs and power lines in at least some parts of the area, which will increase the risk of power outages in the affected areas.

Temperatures will remain well below freezing following the event, bottoming out in the single digits early on Tuesday morning, and not rising above freezing (briefly) until after 12 Noon on Wednesday. This means that the accumulated ice/snow will remain across the area from Monday afternoon through at least Wednesday, which could further hamper efforts to restore power to areas with outages from the storm. As a result of this, we highly recommend that preparations include making sure to have an alternate heating source should your primary source fail as a result of the storm and/or the cold temperatures creating demand that some gas/electric companies cannot fully meet.

...Additional Information on Next Week...
We are also monitoring the potential for another round of wintry precipitation from Tuesday night/pre-dawn Wednesday into the day on Wednesday. Additional details will be provided as we further evaluate the situation.

Significant Winter Weather Impacts Likely Sunday Afternoon thru Monday Morning (and lingering thereafter)

 Expected impacts:

• A mixture of freezing drizzle, freezing rain, sleet and snow is expected to develop around 3pm on Sunday and continue through about 3am on Monday, then change entirely to snow and continue into Monday morning
• Ice accumulation of around 0.1 inch is likely, with amounts of 0.1-0.2 inch possible in some parts of the area, mainly from 3pm Sunday afternoon to Midnight on Sunday night
• Sleet accumulation of up to 0.5 inch is likely, with localized amounts of 0.5-1.0 inch possible in some parts of the area, mainly from 6pm Sunday to 3am Monday
• Snow accumulation of 1-2 inches is likely area-wide, with 2-4 inches possible in some spots, mainly from 3am Monday to 9am Monday
• Northerly winds of 15-25 mph with gusts of 30-35 mph may create areas of blowing snow at times, and the presence of ice/snow and the gusty winds may result in power outages

Probability of the specified ice amount (total) at a given location:

• Probability of <0.1 inch of ice: 70%
• Probability of around 0.1 inch of ice: 50%
• Probability of 0.1-0.2 inch of ice: 30%
• Probability of 0.2-0.3 inch of ice: 20%

Probability of the specified snowfall amount (total) at a given location:

• Probability of ≤0.5 inch of snow: 100%
• Probability of 0.5-1.0 inch of snow: 80%
• Probability of 1.0-1.5 inches of snow: 70%
• Probability of 1.5-2.0 inches of snow: 60%
• Probability of 2.0-3.0 inches of snow: 50%
• Probability of 3.0-4.0 inches of snow: 40%
• Probability of 4.0-5.0 inches of snow: 30%
• Probability of >5.0 inches of snow: 20%

Discussion:
Confidence continues to increase in that a significant, if not major, winter storm will impact the local region from Sunday afternoon through Monday morning, with significant impacts likely area-wide. Furthermore, the fact that temperatures will be well below freezing throughout the period, and afterward, suggest that the impacts will linger for a considerable period of time after the falling precipitation has ended.

A mixture of freezing drizzle, freezing rain, sleet and snow is expected to develop around 3pm on Sunday and continue through about 3am on Monday. The mix is then expected to change entirely to snow and continue through about 9am on Monday morning, then diminish through 12 Noon.

Ice accumulation of around 0.1 inch is likely, with amounts of 0.1-0.2 inch possible in some parts of the area, mainly from 3pm Sunday afternoon to Midnight on Sunday night. Sleet accumulation of up to 0.5 inch is likely, with localized amounts of 0.5-1.0 inch possible in some parts of the area, mainly from 6pm Sunday to 3am Monday.

Snow accumulation of 1-2 inches is likely area-wide, with 2-4 inches possible in some spots, mainly from 3am Monday to 9am Monday.

Northerly winds of 15-25 mph with gusts of 30-35 mph may create areas of blowing snow at times, especially in more open areas with a direct exposure to a Northerly wind. Additionally, what is likely to be the presence of accumulated ice followed by accumulated snow combined with the gusty winds may result in the downing of tree limbs and power lines at times. This will also increase the risk of power outages across many parts of the area during, and after, the event.

Temperatures will remain well below freezing following the event, bottoming out in the single digits early on Tuesday morning, and not rising above freezing until about 9-10am on Wednesday. This means that the accumulated ice/snow will remain across the area from Monday afternoon through midday Wednesday, which could further hamper efforts to restore power to areas with outages from the storm on Sunday night and Monday. As a result of this, we highly recommend that your preparations include making sure that you have an alternate heating source should your primary source fail as a result of this event, and/or the cold temperatures creating demand that some gas/electric companies cannot fully meet.

At Least Light Icing Conditions Likely Saturday/Saturday Night

 Expected impacts:

• Areas of freezing drizzle, patchy, very light freezing rain and possibly some spotty sleet are expected to develop near 5-6am on Saturday and will continue at times through about 4-5pm Saturday
• Freezing drizzle, periods of freezing rain and/or sleet are likely to increase starting around 5-6pm on Saturday and continue through about 2am on Sunday
• The wintry mix is expected to decrease again around 2am on Sunday, and continue through about 6am on Sunday, mainly as patchy freezing drizzle
• Event total ice accumulation of up to 0.1 inch is expected, with 0.1-0.15 inch possible in some spots
• Event total sleet accumulation of a trace or other small amount generally less than 0.25 inch is expected

Probability of the specified ice amount (total) at a given location:

• Probability of <0.1 inch of ice: 70%
• Probability of around 0.1 inch of ice: 60%
• Probability of 0.1-0.2 inch of ice: 40%
• Probability of 0.2-0.3 inch of ice: 20%

Discussion:
Areas of freezing drizzle, patchy, very light freezing rain and possibly some spotty sleet are expected to develop near 5-6am on Saturday and will continue at times through about 4-5pm Saturday. The majority of this precipitation will be very light in intensity and somewhat spotty/intermittent in nature. As a result, significant icing conditions do not appear likely during the bulk of the daytime hours on Saturday at this time.

Freezing drizzle, periods of freezing rain and/or sleet are expected to increase in coverage and intensity starting around 5-6pm on Saturday and continue through about 2am on Sunday. Ice accumulation of up to 0.1 inch is expected, with 0.1-0.15 inch possible in some spots mainly during this time period. Sleet accumulation of a trace or other small amount generally less than 0.25 inch is also expected during this time period.

The wintry mix is expected to decrease in coverage and intensity again around 2am on Sunday, and continue through about 6am on Sunday, mainly as patchy freezing drizzle with little or no additional ice accumulation expected during that time period (however, with temperatures will below freezing, any existing ice conditions are likely to continue into Sunday morning).

With the above trends in mind, we would generally expect the primary concern with regard to hazardous road conditions to develop on Saturday evening and build into the evening and overinght hours. Earlier in the day on Saturday, the primary concern would be patchy, light ice mainly on elevated, metallic and other colder types of surfaces.

Please keep in mind that should even slightly higher ice accumulations occur, the threat for power outages and other issues will increase across the area. It would be wise to prepare as if such conditions may develop, that way you are not caught off guard should the situation intensify.

Please also note that another, likely even more significant, round of wintry weather is expected from Sunday afternoon into Monday morning.  Please refer to the latest post concerning that time period for additional details.

Cooldown to Intensify; Wintry Precip for some Early Thurs/Fri - Likely Everyone Sunday night/Monday...

 

...Overview...

Increasingly cold, arctic air will continue to slowly invade the region through Friday and even more rapidly from Saturday through Tuesday before a moderation in temperature occurs beginning Wednesday of next week. Patchy, light wintry precipitation is possible in Western portions of the local area on Thursday and Friday morning. A more significant round of wintry precipitation is possible area-wide from late Sunday into Monday.

...Regarding Temperatures & Wind Chill Conditions...

Daytime high temperatures will average the 30s Thursday through Saturday, mainly the 20s on Sunday and Monday, and the 30s again by Tuesday and Wednesday. Nighttime/early morning low temperatures will average the lower 30s Thursday and Friday, the low to mid 20s Saturday and Sunday, and the teens on Monday and Tuesday.

Wind Chill values will average the 20s throughout most of the period, except for the single digits and teens from Sunday through Tuesday morning.

...Regarding Patchy, Light Wintry Precipitation on Thursday Morning & Friday Morning...

Patchy, light wintry precipitation is possible in Western parts of the local region (generally West of a line from Canyon Lake to Dripping Springs to Lakeway) mainly between 5am and 9am on Thursday morning, and in the same general area mainly between 4am and 8am on Friday morning. Within this part of the local region, patchy, light ice accumulation is possible especially on elevated, metallic and other colder types of surfaces.

...Regarding A More Significant Round of Wintry Precipitation from Late Sunday into Monday...

Wintry precipitation appears likely area-wide from late Sunday evening or Sunday night into Monday. The potential exists for both freezing drizzle/freezing rain and snow across much of the area during this time period, with potentially significant impacts in at least some parts of the area. We are continuing to monitor this aspect of the situation with more detailed updates to follow, likely beginning tomorrow.

Significant Cold Wave Likely Late Week into Next Week

We are closely monitoring a developing weather situation for the period Friday of this week through Wednesday of next week.  While changes to the forecast are still likely, we wanted to give you a heads-up so that you can prepare for the coming cold weather.

Expected impacts:

•A surge of arctic air is forecast to impact the local region beginning about Friday of this week and continuing through at least Wednesday morning of next week

•During this time period, temperatures will remain at or below freezing for extended periods of time with wind chill values mainly in the teens and 20s for extended periods of time

•Minimum early morning low temperatures will average 15-20 degrees across much of the area, centered on Sunday/Monday

•Daytime high temperatures will average the 30s on Friday/Saturday, the 20s on Sunday, and the lower to middle 30s on Monday/Tuesday

Some light, wintry precipitation is also possible at times from Sunday through Tuesday, but at this time it is too early to be precise with regard to potential impacts

Discussion:

A surge of bitterly cold, arctic air is forecast to impact the local region beginning about Friday of this week (2/12/21) and continuing through at least Wednesday morning of next week (2/17/21). While all details are not 100% certain, we wanted to provide as much notice as possible so that you can prepare accordingly for this event.

During the above mentiond time period, temperatures will remain at or below freezing for extended periods of time with wind chill values mainly in the teens and 20s for extended periods of time. Minimum early morning low temperatures will average 15-20 degrees across much of the area, centered on Sunday and Monday mornings. Daytime high temperatures will average the 30s on Friday/Saturday, the 20s on Sunday, and the lower to middle 30s on Monday and Tuesday.

In addition, several weak upper level weather disturbances are forecast to move across the region during the period Sunday through Tuesday, which will result in the potential for at least occasional, light wintry precipitation at times during that portion of the peirod. At this time it is too early to be precise with regard to potential impacts, but we will continue to monitor the situation closely.

The purpose of this alert is to provide advance notice that temperatures will be significantly colder and for a significant period of time during the above indicated period. We recommend that planning begin now to prepare for the upcoming cold weather, especially due to the relatively mild conditions that we've experienced for much of the winter to this date. We are still in the initial monitoring stages of this event, so expect additional changes to the forecast as we move through the coming days.

Additional Shower & T-Storm Activity Likely - Especially Tonight/Early Tuesday....

Expected impacts:

• Widely scattered showers and isolated thunderstorms are possible across the area today with coverage of around 30 percent likely at any given time
• Periods of showers and thunderstorms are likely from around Midnight or shortly after tonight through about 9am on Tuesday
• Scattered showers and thunderstorms are possible from 9am to 6pm on Tuesday
• Locally heavy rainfall is likely at times with thunderstorms, especially tonight into early Tuesday morning
• Additional rainfall of around 1 inch is likely with localized amounts of 1-2 inches possible in some parts of the area, which is likely to cause minor flooding of low lying and poor drainage areas at times during the period

Details:

...Today and This Evening...
Widely scattered showers and thunderstorms are possible. Coverage will likely average 30 percent throughout most of the period. Generally brief but locally heavy downpours of rain and lightning are possible with any isolated thunderstorms.

...Midnight Tonight thru 9am Tuesday...
Periods of showers and thunderstorms are likely from around Midnight or 1am tonight through about 8 or 9am Tuesday. Locally heavy rainfall can be expected at times during the period, and cloud to ground lightning can be expected with any thunderstorms. Mostly minor flooding of low water crossings and similar flood prone areas can be expected in at least some parts of the area in association with this activity.

There will also be a risk for gusty winds as the (expected) main band of thunderstorms initially approaches the area between Midnight tonight and 2am Tuesday. Present indications suggest the strongest winds will be to the immediate South of the local area, but we'll continue to monitor trends closely as the situation evolves.

...9am Tuesday to 6pm Tuesday...
Scattered showers and thunderstorms are possible during the daytime hours on Tuesday. Coverage will likely average 30 percent in the morning (after 9am) and then 40 percent during the afternoon hours. Generally brief but locally heavy downpours of rain and lightning are likely with any thunderstorms.

Total Rainfall for the Period:

Additional rainfall of around 1 inch is likely with localized amounts of 1-2 inches possible in some parts of the area, the majority of which will occur from Midnight tonight to 9am Tuesday.

Remainder of the Week:

A relative lull in precipitation (with mostly just spotty activity) is expected for Wednesday and Thursday, and then increasing chances of showers and thunderstorms are expected again toward Friday and into next weekend.

UPDATE on Shower/T-Storm Activity This Evening through Tonight (as well as beyond)....

Synopsis:

• Scattered showers and thunderstorms are possible across the area this evening, especially toward/after 8pm, with locally heavy downpours possible in the affected areas
• Periods of showers and thunderstorms are likely from around 10pm or shortly after this evening through about 6am on Monday, with locally heavy rainfall likely and strong, gusty winds possible initially
• Scattered showers and thunderstorms are possible during the daytime and evening hours on Monday
• Periods of showers and thunderstorms are likely from around 2-3am Tuesday through about 9am Tuesday, with locally heavy rainfall possible at times during the period
• Widespread rainfall of 1-2 inches is likely with localized amounts of 2-3 inches possible in some parts of the area, which may lead to at least minor flooding of low lying and poor drainage areas at times during the period

Details:
...Now through 10pm This Evening...
Scattered showers and thunderstorms are possible across the area this evening, especially toward/after 8pm, with locally heavy downpours possible in the affected areas. An isolated stronger thunderstorm could also produce gusty winds and/or hail in the affected portion(s) of the area, again, especially toward/after 8pm.

...10pm This Evening thru 6am Monday Morning...
Periods of showers and thunderstorms are likely. Locally heavy rainfall can be expected at times during the period, and cloud to ground lightning can be expected with any thunderstorms. As the initial main line of thunderstorms approaches a given location late this evening/early tonight (generally between 10pm and 1am), strong, gusty winds are possible in parts of the area.
Minor flooding of some of the typically more vulnerable low water crossings and similar flood prone areas is possible in at least some parts of the area, particularly near/adjacent to areas where downpours are more persistent.

...Daytime and Evening Hours on Monday...
Scattered showers and thunderstorms are possible during the daytime and evening hours on Monday. Coverage will likely average 40 percent throughout most of the period. Generally brief but locally heavy downpours of rain and lightning are likely with any thunderstorms.

...2am Tuesday through 9am Tuesday...
Periods of showers and thunderstorms are likely from around 2-3am Tuesday through about 9am Tuesday. Locally heavy rainfall can be expected at times during the period, and cloud to ground lightning can be expected with any thunderstorms. Mostly minor flooding of low water crossings and similar flood prone areas is possible in at least some parts of the area. This will be of greatest concern in areas that also receive heavy rainfall on Sunday night/Monday morning.

...9am Tuesday to 6pm Tuesday...
Scattered showers and thunderstorms are possible during the daytime and evening hours on Monday. Coverage will likely average 40 percent throughout most of the period. Generally brief but locally heavy downpours of rain and lightning are likely with any thunderstorms.

Total Rainfall for the Period:Widespread rainfall of 1-2 inches is likely with localized amounts of 2-3 inches possible in some parts of the area.

Remainder of the Week: Please be aware that periods of scattered shower and thunderstorm activity are expected again on Wednesday and especially on Thursday and Friday of this week. Depending upon how much rainfall is received beforehand, any additional heavy rainfall during the middle and latter portions of the week could further aggravate the low land flooding potential across the area, and this will need to continue to be monitored closely.

Periods of Showers & T-Storms to Bring Locally Heavy Rainfall Threat This Week

Synopsis/Key Points:

• Isolated to widely spaced showers and isolated thunderstorms are possible at times during the day today and into this evening
• Periods of showers and thunderstorms are likely from around or shortly after Midnight tonight through about 8am on Monday, with locally heavy rainfall possible at times during the period
• Scattered showers and thunderstorms are possible during the daytime and evening hours on Monday
• Periods of showers and thunderstorms are likely from around 2-3am Tuesday through about 9am Tuesday, with locally heavy rainfall possible at times during the period
• Widespread rainfall of 1-2 inches is likely with localized amounts of 2-3 inches possible in some parts of the area, which may lead to at least minor flooding of low lying and poor drainage areas at times during the period

Details by Time Period:

...Today and This Evening...
Isolated to widely spaced showers and isolated thunderstorms are possible at times during the day today and into this evening. Coverage of the activity will likely average 30 percent at any given time, possibly reaching 40 percent during peak afternoon heating. Generally brief but locally heavy downpours of rain and lightning are likely with any isolated thunderstorms.

...Midnight Tonight to 8am Monday Morning...
Periods of showers and thunderstorms are likely from around or shortly after Midnight tonight through about 8am on Monday. Locally heavy rainfall can be expected at times during the period, and cloud to ground lightning can be expected with any thunderstorms. Minor flooding of some of the typically more vulnerable low water crossings and similar flood prone areas is possible in at least some parts of the area, particularly near/adjacent to areas where downpours are more persistent.

...Daytime and Evening Hours on Monday...
Scattered showers and thunderstorms are possible during the daytime and evening hours on Monday. Coverage will likely average 40 percent throughout most of the period. Generally brief but locally heavy downpours of rain and lightning are likely with any thunderstorms.

...2am Tuesday through 9am Tuesday...
Periods of showers and thunderstorms are likely from around 2-3am Tuesday through about 9am Tuesday. Locally heavy rainfall can be expected at times during the period, and cloud to ground lightning can be expected with any thunderstorms. Mostly minor flooding of low water crossings and similar flood prone areas is possible in at least some parts of the area. This will be of greatest concern in areas that also receive heavy rainfall on Sunday night/Monday morning.

...9am Tuesday to 6pm Tuesday...
Scattered showers and thunderstorms are possible during the daytime and evening hours on Monday. Coverage will likely average 40 percent throughout most of the period. Generally brief but locally heavy downpours of rain and lightning are likely with any thunderstorms.

Total Rainfall for the Period:

Widespread rainfall of 1-2 inches is likely with localized amounts of 2-3 inches possible in some parts of the area.

Remainder of the Week:

Please be aware that periods of scattered shower and thunderstorm activity are expected again on Wednesday and especially on Thursday and Friday of this week. Depending upon how much rainfall is received beforehand, any additional heavy rainfall during the middle and latter portions of the week could further aggravate the low land flooding potential across the area, and this will need to continue to be monitored closely.

Strong to Severe Thunderstorms Possible Pre-Dawn Sunday

• Thunderstorms are expected to move West to East across the area from around 3am on Sunday morning through about 6am on Sunday morning
• Locally heavy downpours of rain and frequent lightning can be expected in association with all of this activity
• As the activity initially approaches a given location, strong to possibly damaging wind gusts are possible, and some spotty instances of hail are also possible in some parts of the area
• There is a non-zero chance of an isolated tornado in some parts of the area, but this will strongly depend on the structure of the activity as it approaches

...Timing and Likely Impacts...
Thunderstorms are expected to move West to East across the local area from around 3am on Sunday morning through about 6am on Sunday morning. Locally heavy downpours of rain and frequent lightning can be expected in association with most all of this activity.

...Possible Wind and Hail Impacts...
As the activity initially approaches a given location, strong to possibly damaging wind gusts may occur in at least some parts of the area. Spotty instances of hail are also possible in some parts of the area, but strong, gusty winds are likely to be the primary concern by the time the activity reaches the local area based on present indications.

...Concerning the Possibility of an Isolated Tornado...
When thunderstorm activity initially develops to our West tonight, it will be more isolated/cellular with respect to organization. During this phase, the activity will have the greatest potential to produce a tornado, out to our West over the Hill Country and toward the Big Bend region. As the activity moves Eastward, present indications suggest that it will congeal into more of a band or line, which will reduce the threat of a tornado. So, while a non-zero threat of an isolated tornado does exist locally during the pre-dawn hours of Sunday morning, if the activity congeals into a line or band prior to arrival as currently expected, it will mainly pose a threat of strong to possibly damaging wind gusts as it enters the local area.

...Primary Areas of Uncertainty...
Should the thunderstorm activity that forms to our West tonight not congeal into a line or band before reaching our area during the pre-dawn hours of Sunday morning, the threat of at least isolated tornado activity would increase across the local area. While not currently expected to become a trend overall, we will continue monitoring the situation closely.

...Exit of the Activity...
The thunderstorm activity is expected to shift East out of the area by around 6am or shortly afterward on Sunday morning.

We will continue monitoring the situation and issue updates and/or specific alerts/warnings as conditions warrant.

Majority of Rain with Tropical Disturbance will Remain East of the Metro...

Scattered showers and isolated thunderstorms will continue across the area today. It won't rain all of the time, nor is rain likely to be particularly widespread at any given time. Locally heavy downpours of rain are possible at times with any scattered heavier showers and/or any isolated thunderstorms.

As we've been forecasting throughout this event, we do not expect any significant and/or widespread flooding concerns across the local area with this event. If heavier showers happen to impact a particularly troublesome low water crossing across a specific portion of the area more than once in a short time period, localized/isolated issues may develop at that specific location. Otherwise, the type of activity we're expecting, along with the scattered coverage of that activity, suggest that any local impacts will likely be zero to minimal overall.

Please note that shower and thunderstorm activity will be more widespread, and heavier, further to the East of the local area today, over east-central and southeast Texas.

For the local area, scattered activity is expected to decrease in number after Sunset today, and then end during the pre-dawn hours of Thursday morning, in association with this fetch of tropical moisture anyway.

Scattered Showers & T-Storms Are Possible Tonight/Pre-Dawn Thursday

Scattered to numerous showers and scattered thunderstorms are possible after 10pm this evening (and more likely toward/after Midnight tonight) into the pre-dawn and early morning hours on Thursday.

Locally heavy downpours of rain and lightning are possible with any scattered thunderstorms tonight/pre-dawn Thursday.

While we cannot completely rule out an isolated stronger thunderstorm with strong, gusty winds and/or spotty hail during the overnight hours tonight and/or the pre-dawn hours of Thursday morning, widespread and/or organized severe weather appears unlikely for the local area at this time, as the activity will likely be undergoing a weakening trend due to the time of night.

The activity is expected to shift East/Southeast out of the area by around 6-7am on Thursday morning, based on present indications.

Scattered thunderstorms are possible across the area this afternoon...

...Synopsis...
An area of showers and thunderstorms currently over west-central and northwest Texas will continue moving Eastward and Northeastward throughout the day today. If we were to consider only the present location and movement of this activity, all of it would remain to the North of the local area, with no local impacts of any kind. However, a boundary associated with this activity will move East/Southeast into the local area between the hours of 12 Noon and 6pm this afternoon. The potential exists for at least scattered thunderstorm development in association with the passage of this boundary during the above mentioned time period.

...Local Forecast...
There are 3 possible scenarios that could unfold for the local area at this time, all of which would occur sometime (as indicated below) during the 12 Noon-6pm time frame:

1. With the majority of the energy associated with the parent storm system passing to the North of the local area, thunderstorms are unable to develop locally, and all of the thunderstorm activity remains to the North of the local area. Probability of occurrence: 30 percent.

2. Scattered thunderstorms develop across the area between 12 Noon and 6pm this afternoon. Probability of occurrence: 60 percent. Please note: this doesn't mean that 60 percent of the area will have thunderstorms, but rather, there's a 60 percent chance of scattered thunderstorms across the local area. Some locations may receive rain and/or a thunderstorm while others, possibly very nearby, do not. Based on present indications, under this scenario we would place the probability of a thunderstorm impacting any given location at about 40 percent.

3. A line of thunderstorms moves from West/Northwest to East/Southeast across the area between 12 Noon and 3pm, with scattered activity behind it through 6pm this afternoon. Probability of occurrence: 10 percent.

With the above in mind, we currently expect scattered showers and thunderstorms from around or shortly after 12 Noon through about 6pm this afternoon. Locally heavy downpours of rain and lightning can be expected with any scattered thunderstorms, and an isolated to scattered stronger thunderstorm may also produce strong, gusty winds and/or hail in the affected portion(s) of the area. Present indications suggest the activity will be more numerous, and heavier, to the immediate North of the local area during the period.

...Locally Heavy Rainfall...
Although widespread, heavy rainfall does not currently appear likely across the local area, any isolated to scattered concentrations of heavier downpours could result in minor, mostly localized flooding of low lying and poor drainage areas in the affected portion(s) of the region. The potential for more numerous issues will likely increase as you move further to the North of the local area.



We will continue monitoring the situation and issue updates and/or specific alerts/warnings as conditions warrant.

Details on the Blanco River in southern Hays County....

A Flood Warning continues for the Blanco River in Hays County.  Details by location are as follows:


...At Fischer...
Current stage: 12.3 ft
Flood stage: 17.0 ft

The river is expected to crest just above flood stage later this evening, then recede overnight, falling just below flood stage during the pre-dawn hours on Thursday.

Applicable flood guidance based on previous history (note that guidance for 1 level above the current forecast crest is provided for precautionary/preparedness purposes):

At 23 feet: Lowest homes are threatened. Water begins to cut off secondary roadways near the river.

At 17 feet: Roadways and low bridges along the river are flooded. Vehicles cannot pass. Livestock can be stranded.

At 12 feet: Overbank conditions may cut off livestock in low areas.



...At Wimberley...
Current stage: 8.7 ft
Flood stage: 13.0 ft

The river is expected to crest near 20 feet later this evening, then recede overnight into pre-dawn Thursday. The river is expected to drop just below flood stage near dawn on Thursday.

Applicable flood guidance based on previous history (note that guidance for 1 level above the current forecast crest is provided for precautionary/preparedness purposes):

At 21 feet: Water recreation is very dangerous above Blanco to the San Marcos River confluence, including John Knox Camp and Dudley Johnson Park at Five Mile Dam above San Marcos.  Secondary roads and bridges in the flood plain are very dangerous to motorists. Hydraulic jumps behind low dams are dangerous to canoeists and kayakers as they may become trapped.

At 17 feet: Water recreation in the Blanco river is dangerous from above Blanco to the San Marcos river confluence. Secondary roads and bridges in the flood plain are flooded and dangerous. Much of Dudley Johnson park at Five Mile Dam is flooded.

At 13 feet: Minor lowland flooding reaches secondary roads. Low bridges and crossings from the headwaters to the San Marcos River confluence near San Marcos flood and are dangerous. Property in low lying areas of the Blanco and San Marcos Rivers should be moved to higher ground. Swimming and tubing are life threatening due to turbulence. Hydraulic jumps behind low water dams can trap canoeists and kayakers between the dam and the hydraulic jump and can be life threatening.

At 10 feet: A fast moving rise down the Blanco River can make swimming and canoeing dangerous above Blanco to below San Marcos. Especially in areas where steep banks make getting out of the river dangerous. Low dams create hydraulic jumps which can trap canoeists and kayakers between the dam and the jump.

At 7 feet: Overbank conditions begin to threaten swimmers and tubers in recreation areas above Blanco to the San Marcos River confluence below San Marcos.

At 6 feet: Low lying areas and crossings of secondary roads flood near and below Blanco to below Wimberley including Farm to Market 178 just above Wimberley.



...At San Marcos...
Current stage: 10.32 ft
Flood stage: 18.0 ft

The river is expected to crest near 22.5 feet during the pre-dawn hours of Thursday morning, then recede during the daytime hours on Thursday, falling just below flood stage near 12 Noon.

Applicable flood guidance based on previous history (note that guidance for 1 level above the current forecast crest is provided for precautionary/preparedness purposes):

At 24 feet: Lowest homes are threatened. Water beings to cut off secondary roads near the river.

At 18 feet: Roadways and low bridges along the river are flooded. Vehicles cannot pass. Livestock can be stranded.

At 13 feet: Overbank conditions may cut off livestock and low bridges near the river.



***PLEASE NOTE: ALL of the above forecasts are based on current conditions and short term forecast information. Should additional heavy rainfall occur upstream earlier or in greater quantity than currently expected, the forecast levels and timing could change. We will continue to monitor the situation and issue additional updates as warranted.

Also, additional heavy rainfall later this week will result in additional and/or renewed flooding issues at times across the area through this coming weekend.  We will continue monitoring the situation and issue updates as conditions warrant.

Scattered Heavy Downpours Possible Beginning Today, Increasing Through the Week....

Expected impacts:

• Periods of showers and thunderstorms will produce locally heavy rainfall at times from this afternoon through midday Saturday
• With ground conditions already saturated and stream levels running high across the region, flooding will likely result at least at times during the Watch period
• Initially, the typical problem low water crossings and other typically flood prone areas will be the primary concern, with stream and river flooding then possible over time as we move through the period
• On average, rainfall of 4-6 inches is expected for much of the area mainly from this afternoon through midday Saturday
• Locally higher amounts are possible in spots depending upon exactly where the heaviest rainfall recurs during the period

Discussion:
Periods of showers and thunderstorms will produce locally heavy rainfall at times across the area from this afternoon through midday Saturday. With ground conditions already saturated and stream levels running high across the region, flooding will likely result at least at times during the period. Initially, the typical problem low water crossings and other typically flood prone areas will be the primary concern, with stream and river flooding then possible in parts of the area over time as we move through the period. Please see below for a general overview of our present thinking for each day during the period:

...Today...
Scattered showers are possible this morning, becoming more numerous at times this afternoon into early this evening. Scattered thunderstorms are likely this afternoon into early this evening. The activity is expected to decrease near Sunset.
Low Water Crossing Flood Risk: Low to Moderate (Not widespread, but localized depending upon specific locations of thunderstorms)
River/Stream Flood Risk: Low

...Wednesday...
Scattered to numerous showers and thunderstorms. The activity appears likely to be most numerous during the midday and afternoon hours.
Low Water Crossing Flood Risk: Moderate to High (mainly p.m.)
River/Stream Flood Risk: Low to Moderate (mainly later p.m.)

...Thursday...
Scattered to at times numerous showers and thunderstorms. The activity appears likely to be most numerous during the afternoon and evening hours.
Low Water Crossing Flood Risk: High
River/Stream Flood Risk: Moderate to High on a localized basis

...Friday...
Scattered to at times numerous showers and thunderstorms.
Low Water Crossing Flood Risk: High
River/Stream Flood Risk: Moderate to High on a localized basis

...Saturday...
Scattered to at times numerous showers and scattered thunderstorms. The activity appears likely to be most numerous during the pre-dawn and morning hours.
Low Water Crossing Flood Risk: High (especially a.m.)
River/Stream Flood Risk: Moderate to High on a localized basis

...Expected Rainfall Amounts...
In general, rainfall of 4-6 inches appears probable for most of the area on average throughout the period from this afternoon through midday Saturday. A few locations that receive particularly frequent bouts of heavier rain could see greater than 6 inches, while a few locations that don't receive as many heavy downpours could see less than 4 inches. It is also important to remember that ground conditions are already saturated going into this event, and stream/river levels are already running above normal levels across many parts of the area. Both of those factors indicate that it will take less rain than normal to cause flooding issues across the area.
We will continue monitoring the situation and issue updates as conditions warrant.

Periods of locally heavy rainfall may result in new/renewed flooding this week....

Expected impacts:

• Periods of showers and thunderstorms will produce locally heavy rainfall at several different times mainly from Tuesday afternoon through Saturday morning
• With ground conditions already saturated and stream levels running high across the region, flooding will likely result at least at times during the period
• Initially, the typical problem low water crossings and other typically flood prone areas will be the primary concern, with stream and river flooding then possible in parts of the area over time
• On average, rainfall of 4-6 inches is expected for much of the area from mainly Tuesday afternoon through early Saturday morning
• Locally higher (and in some cases, lower) amounts are possible in spots depending upon exactly where the heavier thunderstorms track throughout the period

Discussion:
Periods of showers and thunderstorms will produce locally heavy rainfall at several different times across the area from Tuesday afternoon through Saturday morning. With ground conditions already saturated and stream levels running high across the region, flooding will likely result at least at times during the period. Initially, the typical problem low water crossings and other typically flood prone areas will be the primary concern, with stream and river flooding then possible in parts of the area over time. Please see below for a general overview of our present thinking for each day during the period:

...Today...
There is a chance for an isolated or widely spaced shower or thunderstorm across some portions of the local area mainly this afternoon or early this evening. While any such activity is expected to be isolated in nature at this time, if locally heavy downpours with an isolated thunderstorm occur in just the wrong place, then some mostly minor flooding issues could result in the adjacent low lying areas. Present indications suggest activity is more likely to occur to the immediate South of the local area today, but we'll continue to monitor trends closely.

...Tuesday...
Scattered to at times numerous showers and scattered thunderstorms. The activity appears likely to be most numerous during the afternoon hours, from 12 Noon to 6pm.
Low Water Crossing Flood Risk: Moderate
River/Stream Flood Risk: Low

...Wednesday...
Scattered to numerous showers and thunderstorms. The activity appears likely to be most numerous during the midday and afternoon hours.
Low Water Crossing Flood Risk: High
River/Stream Flood Risk: Moderate

...Thursday...
Scattered to at times numerous showers and thunderstorms. The activity appears likely to be most numerous during the afternoon and evening hours.
Low Water Crossing Flood Risk: High
River/Stream Flood Risk: Moderate to High on a localized basis

...Friday...
Scattered to at times numerous showers and thunderstorms. The activity appears likely to be most numerous during the morning hours.
Low Water Crossing Flood Risk: High
River/Stream Flood Risk: Moderate to High on a localized basis

...Saturday...
Scattered to at times numerous showers and scattered thunderstorms. The activity appears likely to be most numerous during the pre-dawn and early morning hours.
Low Water Crossing Flood Risk: High (pre-dawn/early a.m.)
River/Stream Flood Risk: Moderate to High on a localized basis

...Expected Rainfall Amounts...
In general --to repeat-- in general, rainfall of 4-6 inches appears probable for most of the area on average throughout the period Tuesday (mainly afternoon) through Saturday morning. We emphasized the "in general" detail because of the fact that actual amounts will widely vary based on thunderstorm tracks throughout the period. A few locations that receive particularly frequent bouts of heavier rain could see greater than 6 inches, while a few locations that don't receive as many heavy downpours could see less than 4 inches. It is also important to remember that ground conditions are already saturated going into this event, and stream/river levels are already running above normal levels across many parts of the area. Both of those factors indicate it will take less rain than normal to cause flooding issues at least at times across the area.
We will continue monitoring the situation and issue specific updates, alerts and/or warnings as conditions warrant.

More potential for locally heavy rainfall beginning Tuesday and then each day thereafter this week...

...Synopsis...
We are continuing to closely monitor a developing weather situation for the period Monday afternoon into Tuesday. While some specific details (as to exact rainfall amounts, etc.) are yet to be worked out, it appears probable that locally heavy rainfall can be expected at times across at least some portions of the area mainly during the day on Tuesday, which could lead to flooding of low lying and poor drainage areas at times. This will be the first of several rain events to impact the area this week, each of which will carry a risk for locally heavy rainfall.

...Forecast...
There is a chance for an isolated or widely scattered shower or thunderstorm on Monday afternoon or Monday evening, but present indications suggest the majority of the area will remain dry during that time period. Showers and thunderstorms are likely to begin developing near dawn on Tuesday and then increase into much of the daytime hours, ending by around 6pm Tuesday. Locally heavy rainfall and lightning can be expected at times with thunderstorms, most numerous at times during the day on Tuesday.

...Flood Risk...
Due to recent heavy rainfall and saturated ground conditions, there will be a higher than normal risk of low land flooding throughout the period in the affected portions of the area, to include probable impacts at times on at least some low water crossings, etc. Present trends suggest that any issue on Monday afternoon or evening would be very isolated. The primary concern is expected to occur during the day on Tuesday especially by the afternoon transportation period, the extent to which will become more clear in later updates.

...A Note About the Remainder of This Week...
Please also be aware that additional periods of shower and thunderstorm activity are likely at various times from Wednesday through Saturday of this week. An elevated risk of low land flooding will continue throughout the week due to recent heavy rainfall, saturated grounds, and the probability of additional heavy rain at times in at least some portions of the local area each day (generally except for Monday).

We will continue monitoring the situation and issue updates as conditions warrant.