Severe Thunderstorm Warning 66, NWS Austin/San Antonio, TX

SOUTH CENTRAL TEXAS FORECAST DISCUSSION...UPDATE
NATIONAL WEATHER SERVICE AUSTIN/SAN ANTONIO TX
1055 AM CDT THU MAY 22 2003

12Z SOUNDINGS AT DRT AND CRP HAD PWATS OF 1.6 AND 1.8 INCHES THIS
MORNING INDICATING THE INCREASE IN MOISTURE ALOFT.  ISOLATED SHOWERS
AND THUNDERSTORMS WERE OCCURRING FROM DEL RIO SOUTHWARD TO LA PRYOR
AND CATARINA.  THIS CONVECTION IS IN RESPONSE TO A WEAK VORT MAX
MOVING SOUTHEAST ACROSS NORTHEAST MEXICO.  CURRENT CONVECTION SHOULD
CONTINUE TO MOVE SOUTHEASTWARD INTO THE CRP CWFA.  ONLY CHANGES TO
CURRENT FCST IS TO REMOVE FOG AND LIMIT TEMP RANGES IN THE ZONE
GROUPINGS TO TWO CATEGORIES.

.EWX...NONE.

13/01

...PREVIOUS DISCUSSION...
IFR CIGS AND PATCHY FOG OVER THE NERN 1/4 OF THE AREA EARLY THIS
MORNING...WHILE THUNDERSTORMS ARE SLOWLY MOVING ESE FROM THE MX
MOUNTAINS TOWARD WRN SECTIONS. THE MAIN FORECAST ISSUES ARE POPS IN
ALL PERIODS...AND TEMPS. THE 00Z NCEP MODELS ARE IN FAIR TO POOR
AGREEMENT...NOT SURPRISING WITH A PATTERN CHANGE UNDERWAY AND THE
NEW PATTERN UPSTREAM BLOCKING WITH NW FLOW OVER TX FOR THE WEEKEND
AND EARLY NEXT WEEK. OVERALL...PREFER THE SHORT RANGE GFS FOR
DETAILS...ESPECIALLY FOR TODAY. THE MEDIUM RANGE MODELS ARE ALSO IN
DISAGREEMENT WITH HANDLING RIPPLES IN THE NW FLOW. WILL BLEND ALL
GUIDANCE...BUT GENERALLY GO WITH TREND OF SLOWLY INCREASING FROM
EARLY TO THE MIDDLE OF NEXT WEEK.

THE 00Z GFS DOES AN EXCELLENT JOB IN IDENTIFYING THE WEAK SHORTWAVE
TROUGH S OF ELP AND THE ASSOCIATED JET STREAK OVER WCNTRL TX AS THE
FORCING FOR THE OVERNIGHT CONVECTION. THE MODEL TAKES THE UPPER
LEVEL FEATURES SSE...DRIVING THE RRQ OF THE JET ROUGHLY ALONG THE
RIO GRANDE THROUGH 18Z. WILL GO WITH THIS PATTERN AND PLACE 30 PCT
POPS OVER THE SWRN ZONES...OTHERWISE DRY FOR THE REST OF SCNTRL TX
TODAY.

THE REMAINDER OF THE FORECAST IS HANDLING POPS IN NW FLOW. IN
GENERAL...POPS RESULT FROM UPSTREAM CONVECTION (GENERALLY ALONG THE
DRY LINE) PROPAGATING ESE IN THE MEAN FLOW...FED BY THE LLJ. IT
WILL TAKE ANOTHER 48 HRS FOR A MOIST/UNSTABLE BOUNDARY LAYER TO
RETURN TO UPSTREAM LOCATIONS...THE LLJ TO STRENGTHEN...AND FOR SFC
HEATING TO OVERCOME THE CAP FOR CONVECTIVE INITIATION. HENCE...WILL
REMOVE POPS THROUGH SAT AFTERNOON AND REINTRODUCE SAT NIGHT.
ALSO...WILL WORK GRIDS AND TEXT TO FOCUS POPS IN THE 05-13Z PERIOD...
AND INCREASE FROM SUN-MON TO TUE-WED...ALTHOUGH STILL IN THE SLIGHT
CHANCE RANGE.

.EWX...NONE.

26/02

PRELIMS...
AUS 080/062 087/064 088 -00 (DRIZZLE THIS MORNING)
DRT 084/066 091/070 094 300
SAT 084/066 087/067 089 000

TXZ171>173-183>194-202>209-217>225-228-231100-

HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE AUSTIN/SAN ANTONIO TX
600 AM CDT THU MAY 22 2003

THIS HAZARDOUS WEATHER OUTLOOK IS FOR SOUTH CENTRAL TEXAS.

.DAY ONE...TODAY
NO HAZARDOUS WEATHER IS EXPECTED AT THIS TIME.

.DAYS TWO THROUGH SEVEN...FRIDAY THROUGH WEDNESDAY
EARLY MORNING THUNDERSTORMS MAY DEVELOP SUNDAY IN NORTHWEST FLOW
ALOFT.  DAMAGING WINDS AND LARGE HAIL ARE A POSSIBILITY IN SUCH
SITUATIONS.  WITH THE NORTHWEST FLOW PATTERN EXPECTED TO CONTINUE
THROUGH WEDNESDAY...FURTHER SEVERE WEATHER EVENTS IN THE FORM OF
DAMAGING WINDS AND LARGE HAIL MAY OCCUR DURING THE LATE NIGHT AND
EARLY MORNING HOURS.

.SPOTTER INFORMATION STATEMENT...
SPOTTER ACTIVATION IS NOT ANTICIPATED.