Houston-Galveston Severe Weather Threat Today
Posted: Wed Nov 26, 2003 7:10 am
SPC puts SE TX and LA in Slight Risk Area. Should not be anything like the previous event.......we hope.
SOUTHEAST TEXAS FORECAST DISCUSSION
NATIONAL WEATHER SERVICE HOUSTON/GALVESTON TX
350 AM CST WED NOV 26 2003
...SEVERE STORMS POSSIBLE THIS AFTERNOON AND EVENING...
LAST NIGHT WE HAD FREEZING TEMPERATURES AT MANY INLAND LOCATIONS.
TONIGHT TEMPS ARE ABOUT 30 DEGREES WARMER WITH ONSHORE FLOW AND A
BLANKET OF CLOUDS. SFC ANALYSIS SHOWS A WEAK BOUNDARY DEVELOPING
JUST OFF THE UPPER TX COAST (POSSIBLY A WARM FRONT). DEWPOINTS HAVE
CLIMBED INTO THE LOWER 60S OVER THE COASTAL COUNTIES.
MAIN FCST CONCERN IS RAIN CHANCES AND SEVERE WEATHER POTENTIAL
TODAY/TNGT. MODELS HAVE BEEN TRENDING SLOWER AND SOMEWHAT WETTER
OVER TIME...AND FOLLOWED ETA RUN WHICH GOES ALONG WITH TREND. MODELS
SHOW 35-40 KNOT LLJ RESULTING IN A TREMENDOUS INCREASE IN MOISTURE
WITH PWS REACHING 1.6-1.7 INCHES ACROSS CWA THIS AFTN. AS FIRST
DISTURBANCE APPROACHES...EXPECT SCATTERED TSRA TO INITIATE ACROSS SE
TX AROUND 21Z. TSRA WILL BECOME MORE NUMEROUS EARLY EVENING AS
SECOND DISTURBANCE NOW NEAR THE BAJA APPROACHES. WILL GO SCATTERED
POPS AREAWIDE THIS AFTN AND LIKELY POPS TONIGHT ERN HALF OF CWA.
THE SEVERE WEATHER THREAT IS MORE COMPLICATED. SHEAR PROFILE QUITE
FAVORABLE WITH HELICITIES INCREASING TO 180-230 M2/S2 AND
SIGNIFICANT DIRECTIONAL SHEAR FROM SFC TO 3000 FT. HOWEVER...THINK
THE ETA IS OVERDOING THE FCST INSTABILITY. IN ADDITION...00Z LCH/CRP
SOUNDINGS SHOWED VERY STRONG CAPPING IN PLACE. IF SFC TEMPS CAN MAKE
IT TO THE 75-78 DEGREE RANGE...THINK THIS WILL BE ENOUGH TO BREAK
CAP. THESE TEMPS COMBINED WITH SFC DEWPOINTS IN THE UPPER 60S WILL
GENERATE CAPES OF 1000-1500 J/KG MAINLY OVER THE SRN HALF OF THE
AREA. WILL MENTION SEVERE ALL ZONES THIS AFTN/EVENING BUT THINK BEST
THREAT WILL BE OVER THE ERN/SRN ZONES. SHEAR PROFILES FAVOR
SUPERCELLS WITH ISOLATED TORNADOES...WITH DAMAGING WINDS A SECONDARY
THREAT. WILL ALSO MENTION HEAVY RAINFALL ERN HALF GIVEN THE HIGH PWS
AND THIS BEING SUCH A BUSY TRAVEL PERIOD.
SOUTHEAST TEXAS FORECAST DISCUSSION
NATIONAL WEATHER SERVICE HOUSTON/GALVESTON TX
350 AM CST WED NOV 26 2003
...SEVERE STORMS POSSIBLE THIS AFTERNOON AND EVENING...
LAST NIGHT WE HAD FREEZING TEMPERATURES AT MANY INLAND LOCATIONS.
TONIGHT TEMPS ARE ABOUT 30 DEGREES WARMER WITH ONSHORE FLOW AND A
BLANKET OF CLOUDS. SFC ANALYSIS SHOWS A WEAK BOUNDARY DEVELOPING
JUST OFF THE UPPER TX COAST (POSSIBLY A WARM FRONT). DEWPOINTS HAVE
CLIMBED INTO THE LOWER 60S OVER THE COASTAL COUNTIES.
MAIN FCST CONCERN IS RAIN CHANCES AND SEVERE WEATHER POTENTIAL
TODAY/TNGT. MODELS HAVE BEEN TRENDING SLOWER AND SOMEWHAT WETTER
OVER TIME...AND FOLLOWED ETA RUN WHICH GOES ALONG WITH TREND. MODELS
SHOW 35-40 KNOT LLJ RESULTING IN A TREMENDOUS INCREASE IN MOISTURE
WITH PWS REACHING 1.6-1.7 INCHES ACROSS CWA THIS AFTN. AS FIRST
DISTURBANCE APPROACHES...EXPECT SCATTERED TSRA TO INITIATE ACROSS SE
TX AROUND 21Z. TSRA WILL BECOME MORE NUMEROUS EARLY EVENING AS
SECOND DISTURBANCE NOW NEAR THE BAJA APPROACHES. WILL GO SCATTERED
POPS AREAWIDE THIS AFTN AND LIKELY POPS TONIGHT ERN HALF OF CWA.
THE SEVERE WEATHER THREAT IS MORE COMPLICATED. SHEAR PROFILE QUITE
FAVORABLE WITH HELICITIES INCREASING TO 180-230 M2/S2 AND
SIGNIFICANT DIRECTIONAL SHEAR FROM SFC TO 3000 FT. HOWEVER...THINK
THE ETA IS OVERDOING THE FCST INSTABILITY. IN ADDITION...00Z LCH/CRP
SOUNDINGS SHOWED VERY STRONG CAPPING IN PLACE. IF SFC TEMPS CAN MAKE
IT TO THE 75-78 DEGREE RANGE...THINK THIS WILL BE ENOUGH TO BREAK
CAP. THESE TEMPS COMBINED WITH SFC DEWPOINTS IN THE UPPER 60S WILL
GENERATE CAPES OF 1000-1500 J/KG MAINLY OVER THE SRN HALF OF THE
AREA. WILL MENTION SEVERE ALL ZONES THIS AFTN/EVENING BUT THINK BEST
THREAT WILL BE OVER THE ERN/SRN ZONES. SHEAR PROFILES FAVOR
SUPERCELLS WITH ISOLATED TORNADOES...WITH DAMAGING WINDS A SECONDARY
THREAT. WILL ALSO MENTION HEAVY RAINFALL ERN HALF GIVEN THE HIGH PWS
AND THIS BEING SUCH A BUSY TRAVEL PERIOD.
