Severe Thunderstorm Warning 137, NWS Houston/Galveston, TX

SOUTHEAST TEXAS FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE HOUSTON/GALVESTON TX
1028 AM CDT TUE AUG 22 2000

...UPDATED TO ADD CHANCE OF SEVERE FOR THIS AFTERNOON...
AFTER CHECKING SOME OF THE LATEST 12Z MODEL DATA AND CONSIDERING
CURRENT CONDITIONS...HAVE DECIDED TO GO AHEAD WITH SEVERE CHANCES.
WILL ALSO ADD THIS TO THE EVENING WORDING.

PREV DISC...
MAIN FORECAST CHALLENGE TODAY CONCERNS RAIN CHANCES.  FACTORS IN THIS
REGARD ARE THE UPPER LOW LOCATED JUST SOUTHWEST OF BROWNSVILLE AT
12Z...A WEAK SURFACE BOUNDARY ALONG THE UPPER TX COAST...AND AN
UNSTABLE AND MOIST ATMOSPHERE OVER SETX.  FOR THE LAST ITEM PW/S WERE
1.8 AT LCH AND 1.9 AT CRP...LI/S WERE -8 AT LCH AND -6 AT CRP...K-
INDICES WERE 23 AT LCH AND 36 AT CRP...AND CAPES WERE 4600 AT LCH AND
3400 AT CRP.  THE WATER VAPOR AND SOUNDINGS SHOWED SOME DRY AIR
FILTERING INTO THE AREA FROM THE NORTHEAST ACROSS LA AND SOME SHALLOW
LOW-LEVEL STABILITY ACROSS E TX.  FEEL THAT THERE MAY BE SOME ISOLATED
SEVERE CHANCES TOWARD THE EVENING TIME FRAME...BUT WILL HOLD OFF
MENTIONING THIS POSSIBILITY UNTIL THE 4 PM PACKAGE TO CONSIDER THE 12Z
MODEL DATA.  AT THE MOMENT ISOLATED SHOWERS AND THUNDERSTORMS WERE
OCCURRING OVER THE COASTAL WATERS AND IMMEDIATE COASTAL AREAS AS THE
CIRCULATION AROUND THE UPPER LOW HAS INTERACTED WITH THE SURFACE
TROUGH.  FEEL THAT AS THE DAY PROGRESSES A COMBINATION OF DAYTIME
HEATING AND THE SEABREEZE WILL HELP PRODUCE SCATTERED CONVECTION
ACROSS THE FORECAST AREA.  THE MOTION OF THE STORMS WILL LIKELY BE
NORTHWESTWARD AT FIRST...THEN TURN TOWARD THE WEST AS THE STORMS GET
STRONGER.  POPS FOR THE MOST PART LOOK GOOD...THOUGH WILL UP THE
CENTRAL A^REAS TO 30 PERCENT IN THE SECOND PERIOD TO MAINLY ACCOUNT FOR
THE EXPECTED COVERAGE DURING THE EARLY EVENING HOURS.

PL-40
41

.HGX...NONE.