Daily General Weather Discussion Thread #11

HOUSTON:

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE HOUSTON/GALVESTON TX
335 PM CDT THU JUN 12 2014

...SLIGHT RISK OF SEVERE STORMS TONIGHT...

.DISCUSSION...
THIS FORECAST UPDATE FOCUSED MAINLY ON THE POTENTIAL FOR SEVERE
WEATHER TONIGHT INTO FRIDAY MORNING. LATEST VIS SATELLITE AND SFC
OBS SHOW OUTFLOW BOUNDARY FROM BASICALLY JASPER TX TO STEPHENVILLE
TX THIS AFTERNOON. STORMS STARTING TO DEVELOP JUST NORTH OF THE
BOUNDARY OVER TX SHOULD BE ABLE TO TAP STRONG INSTABILITY TO
ITSELF AS OUTFLOW BOUNDARY DISSIPATES. SPC RAP MESO ANALYSIS SHOWS
QUITE A BIT OF INSTABILITY OVER THE SEVERE WEATHER RISK AREA.
WATER VAPOR IMAGERY SHOWS DRY SLOT AND SHORTWAVE TROUGH AXIS ALSO
PUSHING OVER THE REGION. ALSO MAY SEE AN AREA OF ENHANCED JET
STREAM WINDS OVER THIS REGION AS WELL. THIS SHOULD FURTHER HELP
SUPPORT CONVECTIVE INITIATION THE NEXT SEVERAL HRS. OVERALL THE
ENVIRONMENT LOOKS FAVORABLE FOR ORGANIZED CONVECTION THIS EVENING
AND TONIGHT ACROSS MUCH OF TX.

MESO MODELS OF HRRR/WRF-ARW/NMM AND WRF RUN BY TX TECH ALL SHOW A
LINE OF STORMS MOVING INTO SE TX AROUND 01-04Z THIS EVENING. THE
12Z NAM ALSO HINTS AT THIS WITH THE OTHER SYNOPTIC MODELS SHOWING
HIGH QPF OVER C TX INTO SE TX INDICATIVE OF CONVECTION. GIVEN ALL
THIS AGREEMENT ADDED 70 POPS TO THE FORECAST WITH MENTION OF
SEVERE STORMS FOR TONIGHT. LIKE TIMING OF REACHING NORTHERN THIRD
OF THE FORECAST AREA FROM 00Z-04Z AND THEN HOUSTON AREA AROUND
03Z-07Z. DEPENDING ON HOW CONVECTION EVOLVES...SQUALL LINE COULD
BE SLOWER IF IT TAKES MORE TIME TO DEVELOP. INSTABILITY AND SHEAR
PARAMETERS SUPPORT BOWING SEGMENTS WITH THE SQUALL LINE. WRF-ARW
REALLY SHOWS THIS STRUCTURE WELL AT 03Z TONIGHT. THINK DAMAGING
WIND/HAIL THREAT WILL BE MAIN CONCERN. SHOULD BOW ECHOES
FORM...HIGHER CHANCE FOR WIND DAMAGE AND POWER OUTAGES ACROSS THE
AREA. MODELS DO SHOW SQUALL LINE WEAKENING AS IT MOVES INTO THE
HOUSTON AREA SO IMPACTS MAY BE LESS FARTHER SOUTH THAN BRAZOS
VALLEY INTO EAST TEXAS. STILL LOW CHANCES OF THE LINE MAKING IT TO
THE COAST BUT WILL LARGELY DEPEND ON STRENGTH OF COLD POOL AND CAP
WEAKENING. AS SUCH HAVE TAPERED OFF POPS FOR TONIGHT CLOSER TO THE
COAST SOUTH OF I-10.

FRIDAY MAY STILL HAVE SOME CHANCES OF THUNDERSTORMS. MAIN
SHORTWAVE TROUGH AXIS WILL FINALLY ROTATE THROUGH WITH A BACK
DOOR FRONT APPROACHING THE AREA. GFS/NAM/ECMWF HINT AT SOME
DEVELOPMENT ALONG THIS BOUNDARY WITH PASSING TROUGH AXIS. KEPT
SOME 30 POPS IN THE FORECAST BUT OVERNIGHT SQUALL LINE COULD HAVE
REALLY WORKED OVER THE BOUNDARY LAYER AND DOUBT THERE WILL BE MUCH
RECOVERY. GFS DOES HINT AT PRECIP WATER VALUES AROUND 1.8-2.0
INCHES SO WITH TEMPS IN THE UPPER 80S TO LOW 90S TOMORROW...COULD
SEE STORMS DEVELOP AGAIN ALONG THE BOUNDARY. SEVERE THREAT LOOKS
LOW BUT AGAIN COULD SEE A WIND THREAT WITH BRIEF HEAVY RAINFALL.

REST OF THE FORECAST LOOKS ON TRACK WHEN LOOKING AT GFS/ECMWF DATA
FOR THE EXTENDED. RAIN CHANCES LOOK MINIMAL SAT BUT COULD GET SOME
ISO ACTIVITY SUN/MON. REST OF THE WEEK WILL BE QUESTIONABLE AS TO
THE STRENGTH OF THE RIDGE AND ANY LINGERING DEEP MOISTURE. SUPPOSE
THAT SEA BREEZE COULD DEVELOP TO SUPPORT A STORM OR TWO BUT TOO
FAR OUT TO PINPOINT MESOSCALE FORECAST DETAILS.

Looking northwest on WV, it does look like some more energy is beginning to dig southeast across north TX, OK, and KS. Any thoughts on how this might play out with any additional thunderstorms threatening southern Louisiana and Mississippi?

That outflow has some pretty gusty winds with it. I'd say 30-40 mph.