A large area of rain showers and thunderstorms is forecast to develop across West Texas this evening and spread across the Hill Country and Central Texas regions tonight into Tuesday morning. This large area of rain is forecast to move over the middle Texas coast throughout the day on Tuesday.
Midday observations showed a cloudy sky covering the Hill Country and Central Texas regions as Gulf moisture was spreading to the north in advance of a Pacific storm system. Today's temperature will be slightly cooler due to the clouds and a weak cold front which pushed south across the area on Sunday. Early this afternoon, the front was lifting back to the north as a warm front, stretching from near Houston to Bastrop, San Antonio and Eagle Pass. With the front moving north, it will allow very moist air mass to spread north from the Gulf tonight into Tuesday. This afternoon, a few spotty light rain showers will be possible across the region, but most locations will stay dry. High temperatures will range from near 60 degrees across the northern Hill Country to the low and mid-70s across Central Texas to around 78-80 degrees near the coast.
A large area of low pressure in the upper atmosphere is currently centered just south of Arizona, over northwestern Mexico. The low is forecast to move east-northeast across northern Mexico tonight, tracking across western and northwestern Texas on Tuesday and finally exiting to the middle Mississippi Valley region late Tuesday. This evening, rain showers and scattered thunderstorms are forecast to increase in areal coverage across West Texas and the western Hill Country as the atmosphere becomes increasingly moist and unstable in advance of the low pressure system. By about midnight, this area of rain and thunderstorms is forecast to slowly organize into large north-south oriented complex of rain showers and thunderstorms. This complex of rain and storms is expected to spread east across the Hill Country overnight, reaching the Interstate 35 corridor by about daybreak Tuesday, and the coastal plains region around late morning.
Today's forecast data indicates some of the thunderstorms tonight and Tuesday could approach severe levels, producing large hail, damaging downburst winds and even a couple of isolated tornadoes. The Storm Prediction Center has placed the Hill Country and the I-35 corridor under a Marginal Risk for severe thunderstorms through 6 am Tuesday. A marginal risk means the forecasters feel isolated severe thunderstorms will be possible. The marginal risk for severe thunderstorms will continue across the Austin/Interstate 35 corridor Tuesday morning. But for areas east of I-35, the threat for severe storms will be greater, due to increased instability. The Storm Prediction Center has placed all of Southeast Texas, including Fayette, Colorado, Wharton and Matagorda Counties under an Enhanced Risk for severe thunderstorms throughout the day on Tuesday. An enhanced risk means the forecasters feel numerous severe thunderstorms will be possible, producing large hail, damaging winds and isolated tornadoes.
Moderate to occasionally heavy rain is forecast with the thunderstorm complex as it slowly spreads to the east Monday night through Tuesday. While widespread flash flooding is not anticipated, the rain will cause rises on area creeks and streams and may lead to some street flooding in the more urban areas. The National Weather Service's latest rainfall forecast, for the period 6 pm Monday through 6 pm Tuesday, calls for widespread totals of 1-2 inches, with isolated totals to near 3 inches possible.NWS rainfall forecast for the period from 6 pm Monday through 6 pm Tuesday:
The rain and thunderstorms look to taper off across the Hill Country Tuesday morning. The rain should end from west to east across Central Texas and the middle Texas coast Tuesday afternoon. A Canadian cold front is forecast to spread south across the region in the wake of the rain complex Monday night into Tuesday, causing breezy and cooler conditions. High temperatures Tuesday are forecast to be in the low 50s across the Hill Country, in the mid and upper 50s across Central Texas and the low 70s across the coastal plains. Expect a northwesterly breeze at 10-15 mph. Mostly cloudy, dry and cool weather is forecast Tuesday night. Low temperatures Wednesday morning are forecast to be near 38-40 degrees across the Hill Country, the low 40s across Central Texas and the mid to upper 40s across the coastal plains.
Mostly sunny and dry weather is expected across the region Wednesday through Saturday as a weak ridge of high pressure develops across Texas the southern Plains states. High temperatures look to be near 58-62 degrees Wednesday, in the low and mid-60s on Thursday and in the low 70s Friday. Readings are forecast to warm to around 78-80 degrees on Saturday. Low temperatures Thursday and Friday mornings will range from the mid and upper 30s across the Hill Country to the low and mid-40s near the coast. Low temperatures Saturday morning will be in the 50s.
Medium-range forecast solutions indicate another area of low pressure from the Pacific will track east across northern Mexico next weekend, moving across Texas late Sunday into Monday. This system is forecast to bring an area of rain showers and thunderstorms to Central and South Texas next Sunday and Monday. As of now, rain amounts from this system are forecast to total around 1-1.5 inches.
Generally dry and mild weather conditions are forecast next Tuesday through Friday. High temperatures are forecast to be in the 70s, with low temperatures in the 40s and 50s.
Have a good week.