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.