WINTER WEATHER UPDATE: Extreme Cold and Potential Ice

WINTER WEATHER UPDATE:Extreme Cold and Potential Ice/Sleet February 14-16

www.weather.gov/rgv

Sunday, February 14 2021

NWSBrownsville

2:00 PM CT

Prepared by: Barry Goldsmith

WFO Brownsville/Rio Grande Valley

Disclaimer: The information contained within is time-sensitive. Do not use after 7 AM CST Monday.

2/14/2021 2:53 PM www.weather.gov/rgv

Brownsville/RGVWEATHER FORECAST OFFICE

Situation Overview: The “Skinny”

Bottom Lines:▪ Life-Threatening wind chill (“feels like”) temperature

expected Monday, worst between 6 and 9 AM.

▪ Hard and damaging freezes are also likely Monday and Tuesday mornings. Coldest “night/day/night” period since Dec. 1989

▪ A period of freezing rain (glaze ice) will turn over to ice pellets, perhaps ending with a few snow flurries, between this evening and just after daybreak Monday morning

▪ The ice may coat surfaces prior to the sleet (pellets)…coldest temperatures following end of precipitation may produce a dangerous “flash” freeze

▪ Through Tuesday, temperature will range from 25 to 35 degrees below average, possibly as much as 40 degrees below average Monday morning through Tuesday afternoon. Average is 75 by afternoon, 52-55 by daybreak.

▪ Much below average temperatures are now guaranteed through the end of next week (February 19) Forecast position of arctic high (US model, top) and “expected”

forecast and departure from average for minimum temps Feb. 15 morning.



Rio Grande Valley/Deep S. Texas OutlookLife-Threatening Wind Chills, a Hard Freeze, and Ice/Sleet

Sunday Night• Freezing/Frozen Precipitation (ice, then

sleet) Develops soon after sunset

ranchlands; mid to late evening Valley

• “Feels Like” temperatures falling to 10s-

20s˚ after midnight; 10-15 by sunrise.

Monday• Likelihood for Minor Icing and Sleet through Pre-

Dawn west, 8/9 AM near Coast. “Flash” Freeze

Possible

• “Feels Like” Temperatures droping to 8 to 18˚ from

dawn-9 AM. Could be as low as 5˚

• Actual temperatures falling to 21-28˚ by 7 AM but

could be as low as 18-25 by 8 AM; low-mid 30s after

noon Valley with at or just below 32˚F ranchlands

Tuesday Morning• Hard Freeze potential for many

through mid morning…17 to 25˚

• Even with lighter winds, “feels

like” temps 6 to 18˚ by 7/8 AM

• Slow recovery by afternoon (upper

30 to mid 40s)

Feb 13

Sunday Night TuesdayMondayFeb 14 Feb 15 Feb 16

Late Morning/

Aftn

Morning



• Tonight/Early Monday (Feb 14-15):

• Arctic “blast” surges in between 6-7 PM and 3 AM

• Rain beginning to freeze (ice up) as early as sunset N. Zapata east to N. Kenedy; light sleet (ice pellets) between midnight and daybreak

• Rain beginning to freeze (ice up) between 9 PM-midnight for the Rio Grande Valley – but sleet could also occur in theValley by 3 AM

• Temperatures crashing from 34 to 39 at 6 pm to between 22 and 27 between 6 AM and 9 AM Monday. Potential for upper teens

to mid 20s (all areas; coldest N. Zapata, Jim Hogg, Brooks, Kenedy, Willacy, N. Hidalgo)

• “Feels Like” Temperatures expected to be 8 to 18˚F, coldest near coast and across ranchlands. Could be as low as 5˚F

Harlingen-Bayview!

• Untreated roads will be very dangerous in this scenario for the Monday commute! A “flash freeze” could occur

immediately after precipitation ends and temperatures bottom out.

• Monday Afternoon (Feb. 15)

– Actual temperatures forecast to rise slowly and get above freezing by noon, but range from 29 to 35 by mid afternoon. Potential for

readings to remain below freezing Zapata through Kenedy

– “Feels like” temperatures only rising to 12 to 25˚F, coldest toward the coast

• Tuesday (Feb 16)

– Another hard freeze for all of the Rio Grande Valley/Deep S. Texas region; morning lows between 17 and 25˚F. If skies stay cloudy,

temperatures would be not as cold (20s) but still a hard freeze for most.

– A slow rise in temperatures, getting above freezing by noon

Forecast Situation – Deep FreezeSunday through Tuesday, Feb 14-16



• Dangerously cold for persons exposed to the elements without adequate

clothing or shelter. Critical danger for frostbite and death from 12 AM to Noon

Monday, and midnight to 9 AM Tuesday.

• High use of heating could stress the local and statewide power grid, with

potential neighborhood outages. Peak potential: 12 AM Monday through 12 PM

Tuesday.

• House fires could start from incorrect use of space heaters or other non-

traditional heat sources

• Potential for pipe bursts in residences and water main breaks in

communities due to extreme cold

• 12 AM Monday through 12 PM Monday: Potential for very dangerous

driving conditions on untreated roads due to the combination of light

freezing/frozen precipitation and temperatures in the 20s.

Potential Impacts – On LandFebruary 14 late evening - February 16th noon



• 12 AM Monday through 12 AM Tuesday - Over Laguna Madre and the Gulf:

Likelihood of a Gale event with strong winds over 40 knots and very

high and extremely rough seas – Beaufort Scale 8 – from 12 AM Monday

through 12 AM Tuesday (longest over the Gulf)

• 6 AM Monday through 9 AM Tuesday: Over Laguna Madre and Gulf: “Sea

Smoke” may form due to the very cold air overrunning the warm sea

surface, reducing visibility below 1 nautical mile. Freezing Spray possible along

Laguna Madre.

• Through the Period: Coastal waterways – Pelicans may become trapped

along Padre Boulevard especially Sunday night through Monday evening. Sea

turtle “stunning” is likely, peaking Monday through Wednesday

Potential Impacts – On WaterThrough Tuesday, February 16th

www.weather.gov/CorpusChristi

Corpus ChristiWEATHER FORECAST OFFICE

Winter Storm/Wind Chill Warning

• Best Prospect for more Precipitation: Jim Hogg-Kenedy

• **ANY** Glaze Ice at forecast temperatures (low to mid 20s) is dangerous!!

• Sleet is now expected in all areas,but glaze ice will likely coatuntreated surfaces underneath anysleet accumulation

• A Hard Freeze (27 or lower forseveral hours) Is Expected for al but the Barrier Island (Still a Freeze).

www.weather.gov/CorpusChristi

Corpus ChristiWEATHER FORECAST OFFICE

Ice/Sleet Accumulation Map

Best Timing Estimate: • RG Plains/Upper Valley – Starting

after sunset, ending by 2/3 AM• Brooks/Mid Valley: Starting 6-9

PM (Brooks); 9- Midnight (Hidalgo), ending 4-6 AM

• King Ranch/Lower Valley: Starting6-9 PM (Kenedy, possibly Willacy; 9-Midnight (elsewhere except near coast); ending 6-8 AM

All Areas: Brief period of Icing (Freezing Rain) followed by Ice Pellets (Sleet)



Wind Chill Forecast Maps

Could be lower than shown Harlingen-Brownsville to Laguna

Madre if winds stronger/temps lower. 8 to 12˚F possible by 8 AM.

Winds will be lighter (5-10 mph), but temperatures lower, hence

Similar wind chill readings to Monday. Highest in LowerValley/toward coast.



Safety Infographics – HypothermiaSunday, Feb 14 10 PM through Tuesday, February 16 Noon



Safety Infographics – HeatersThrough Tuesday, February 16th, and Beyond



Safety Infographics – DrivingFebruary 14-15 (10 PM to Noon)

These tips also apply for light

ice pellets (sleet)

We strongly urge everyone to remain

off the roads Monday, at least through

noon.



Safety Infographics – DressingThrough Sunday, February 14 and beyond

“Extreme Cold” –

Late Tonight Through

Tuesday Noon



Safety Infographics – Four P’sThrough Sunday, February 14 and beyond

Protect People! Check on the elderly/infirm and other

persons without heat,

and ensure they have a safe, warm place to be this

weekend. Check for open shelters in your community.

Protect Pets! Bring house pets indoors especially

This evening through Tuesday, when freezing

temperatures are most likely and they could be injured

or die. Ranchers…finalize livestock protection, too!

Protect Plants! Cover, or move indoors, new

vegetation or tender tropical plants

no later than sunset to be on the safe side.

Protect Pipes! Cover (insulate) outdoor or exposed

pipes not later than sunset.

Consider a slow drip of water overnight through Tuesday

noon.



Safety Infographics – Pelican WatchThrough Sunday, February 14 and beyond

Pelicans flying toward Bahia Grande, through Saturday and again Sunday night-Monday



Record Cold Forecast!February 16 Low (Minimum) Temperatures



Record Cold Forecast!February 16 Low (Minimum) Temperatures



▪ Prepare for a prolonged period of cold weather, with greatest danger potential from Sunday overnight through Tuesday noon (Feb 14-16)

▪ Duration of freezing (≤32˚F) Monday into early Tuesday could range from several hours to more than a day across ranch country, which would be the most since February 2-4, 2011’s ice storm event

▪ Duration and intensity of the cold will determine the extent of any agricultural and livestock damage, especially coming this late in the season

▪ We strongly urge getting at-risk people to heated locations by sunset, and all to remain off the roads Monday morning (at least): Empty roads are Safe roads!

Key Take-Aways

https://www.weather.gov/bro/2011event_earlyfebwinterstorm

www.weather.gov/rgv@NWSBrownsville

The Next Briefing:

2-3 PM CT Monday, February 15

Method: Email

Web: http://weather.gov/rgv

Phone: (956) 504-1432 x2

E-mail: [email protected]

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WINTER WEATHER UPDATE: Extreme Cold and Potential Ice