Strong storm system digging into the SW US will bring highly active weather to TX Monday and Tuesday.
Risks are severe weather including damaging winds and tornadoes and heavy rainfall.
Upper level storm system and deepening upper level trough over the Rockies will eject into the plains Monday and Tuesday. Strong pressure falls over NW TX late today will force surface low pressure which will rapidly deepen as it moves NE toward KS on Monday into Tuesday. A strong cold front will blast SE across TX late Monday into Tuesday with a significant temperature gradient across the state by Tuesday morning. This system features fairly impressive dynamics and wind energy aloft and this will likely translate into a severe weather outbreak over portions of TX Monday afternoon through the day on Tuesday.
Monday:
Dry low level air mass in place will begin to undergo moistening tonight as coastal warm front begins to work northward. High resolution guidance is slow in advancing this boundary northward on Monday and keeps dewpoints in the upper 50’s and lower 60’s. The pace of northward movement will likely become a function of how much shower and thunderstorm development occurs along and north of the boundary. Models are not overly aggressive with development on Monday, but factors will be coming together including an increasing warm advection pattern coupled with weak disturbances moving across the area in the flow aloft from the SW. Severe parameters look week on Monday with only modest low level wind shear in place. Think there could be some strong storms, but severe weather looks less likely.
Monday night:
Strong low level jet will be in place with increasing wind fields aloft as the core of a 120kt upper level jet streak moves into C TX. Upper winds become increasingly diffluent (spreading apart) which will enhance the lift over the area. New development in some of the latest model runs is a slight veering of the low level wind field to the SSW which may advect a mid level capping inversion NE into portions of SE TX. This could help to prevent warm sector storm development on Monday night, but it is uncertain exactly how far NE this capping may extend into the area and if the increasing lift approaching from the west could erode any capping. With increasing wind profiles severe thunderstorms would be possible if they were to develop within the warm sector.
Tuesday:
Highly moist and moderately unstable air mass will be in place by Tuesday morning. Strong cold front will be located along I-35 by early morning (600am) and progress eastward into SE TX throughout the day. Expect a strong squall line of thunderstorms to exist along this front with severe weather likely. Air mass over SE TX will warm into the mid 70’s to low 80’s resulting in building instability ahead of the front with CAPE of 1000-1500 J/kg. Low level wind fields certainly show a significant degree of turning with helicity values of 200-400 m^2/s^2 over SE TX. Strong wind energy both near the surface and aloft will support a damaging wind threat with any of the storms. Linear forcing along the cold front will likely maintain the squall line across the region with wind damage the main threat with the line. May see a few discrete cells develop ahead of the main line and these storms could become tornadic with all the low level turning in place. May also see weak short lived tornadoes along the main squall line. Expect the cold front to reach our western counties in the 800am-1000am time frame and into the central counties (metro Houston) between 1000am and 300pm and then exit our eastern counties between 200pm and 600pm.
High moisture levels will accompany this storm system with PWS rising to near 2.0 inches by early Tuesday morning. Excessive rainfall will be likely with the strongest storms with rainfall rates of 2-3 inches per hour. Overall fast forward progression of the cold front and thunderstorms should help to negate a significant flash flood threat however urban ponding on roadways will be possible as the storms move across the region. Still concerned for a period of possible cell training of thunderstorms early Tuesday morning ahead of the main squall line which could add up rainfall totals, but this threat is conditional on actual develop over the warm sector which becomes a function of the mid level capping intensity. Widespread rainfall amounts of 1-2 inches are likely with isolated amounts of 3-5 inches. The heaviest rainfall will likely be NE of a line from College Station to Conroe to Liberty.
Coldest air of the fall season will usher into the region behind the Tuesday afternoon frontal passage. Temperatures will fall from the 70’s into the 60’s and may be even the 50’s post front. Lows Wednesday morning will likely fall into the 40’s over much of the region. High pressure builds into the region Wednesday-Saturday with cool morning lows in the 50’s and highs in the 70’s.
Next storm system looks like another potential big weather maker for the week of Thanksgiving as it takes a similar low latitude route and entrains a good chunk of cold air. This time period is still out there in the longer range…but it looks cold and potentially wet for much of Thanksgiving week.
SPC Severe Weather Outlook for Tuesday:
