Very Cold Air Arriving Wednesday Night. Wintery Precipitation Possible Thursday Morning - LCRA Very Cold Air Arriving Wednesday Night. Wintery Precipitation Possible Thursday Morning - LCRA


Widespread rain showers and isolated thunderstorms spread east across the Hill Country, Central Texas, and coastal regions late Sunday night into Monday morning in advance of a trough of low pressure moving out of West Texas. As of midday Monday, LCRA’s Hydromet showed totals have generally been in the range of a third to a half inch across the Hill Country, between a half inch and two inches across Central Texas, and between a half inch and 1 inch across the middle Texas coast. Today’s rain is being generated by a trough of low pressure in the upper atmosphere that is slowly tracking east-southeast over Central Texas.

High-resolution forecasts call for the rain to end across the Hill Country early this afternoon. To the east, additional waves of rain showers and thunderstorms do look to continue across Central Texas and the middle Texas coast throughout the afternoon. The rain should taper off from west to east late this afternoon into the evening. Some of this afternoon’s rain may be locally heavy, producing quite a bit of rain in a short period of time. This rain could quickly fill culverts, cause ponding on roads, and possibly close some low-water crossings. The National Weather Service has posted a Flood Watch for the I-35 corridor between Georgetown and San Marcos and areas east through late this evening. There will be a potential for additional totals of 1-2 across parts of Central Texas. Across the middle Texas coast, widespread totals of 2-4 inches are forecast, along with isolated heavier totals.

Dry weather is forecast tonight through Tuesday night as the upper trough exits the region. Clouds Tuesday morning will give way to sunshine and warm temperatures in the afternoon. Expect a high temperature close to 70 degrees. Lows Wednesday morning will be in the low and mid-50s.

Arctic Air Invasion

Monday morning’s forecast data continues to indicate arctic air will spill south into Texas late Wednesday into Thursday morning. This is shaping up to be the coldest air we have seen so far this winter. But unlike previous arctic out breaks this winter, this one is expected to be accompanied by precipitation on the front end. A large trough of low pressure sinking southeast out of the southern Plains and the Desert Southwest on Wednesday is expected to cause the development of widespread rain showers and isolated thunderstorms across the region Wednesday afternoon through Wednesday night. Rain totals of 0.25-0.5 inches are forecast. Temperatures will be mild Wednesday, with readings reaching the 50s across the Hill Country, the 60s across Central Texas and the mid-70s across the coastal plains.

The arctic front is forecast to spread across the Hill Country Wednesday afternoon, the Central Texas region Wednesday evening and the coastal plains region around or just after midnight Wednesday night. Windy conditions and much colder air will spread in behind the cold front Wednesday night. Readings are forecast to fall below freezing across the Hill Country and most of Central Texas before sunrise Thursday and remain below freezing throughout the day. Brisk northerly winds are expected to produce wind chill values in the single digits across the Hill Country, and in the teens to low 20s elsewhere on Thursday.

Forecasts call for precipitation to continue across the region behind the cold front Wednesday night through about midday Thursday. With readings forecast to fall below freezing across the Hill Country and Central Texas regions after midnight, light rain is expected to transition to freezing rain and eventually freezing rain and sleet around sunrise Thursday. The threat for wintery precipitation is predicted to extend southeast to a line stretching roughly from Brenham, to La Grange, to New Braunfels. Snow is not expected across our area due to warmer temperatures in the middle atmosphere over the central part of the state. However, some light snow will be possible across the western and northern Hill Country regions as well as much of West Texas.

Light ice accumulations are expected across the Hill Country and the Austin/Interstate 35 corridor Thursday morning. Confidence is starting to increase there will be icing impacts throughout the Hill Country and on elevated surfaces throughout the Austin and I-35 corridor Thursday morning.

The precipitation is forecast to end from west to east Thursday afternoon as the overrunning pattern eases. Clouds should decrease and the sky become mostly sunny Friday. Sunny, dry, but cold weather is expected to continue through the weekend.

Very cold temperatures are forecast Thursday, Friday and the weekend. The coldest temperatures look to occur Friday and Saturday mornings,

where lows in the teens and 20s are forecast. Highs only in the 30s to low 40s are forecast Friday and 40s to low 50s Saturday.

Here is my latest thinking on temperatures for the upcoming period.

  • Lows Thursday morning upper teens to low 20s Hill Country, upper 20s to 30 degrees Austin area, mid 30s to low 40s elsewhere.
  • High temperatures Thursday upper 20s Hill Country, near 30 degrees in the Austin area, mid-30s Central Texas, and near 40 coastal region.
  • Low temperatures Friday and Saturday mornings mid and upper teens Hill Country, near 20-22 degrees Austin area, mid-20s coastal region.
  • High temperatures Friday mid and upper 30s and near 40 near the coast.
  • High temperatures Saturday in the low 40s.
  • Lows Sunday morning low 20s Hill Country, mid and upper 20s Central Texas area, with low 30s coastal region.
  • High temperatures Sunday in the low 50s.

Bob