Severe Thunderstorm Warning 121, NWS Austin/San Antonio, TX

SOUTH CENTRAL TEXAS FORECAST DISCUSSION...UPDATE
NATIONAL WEATHER SERVICE AUSTIN/SAN ANTONIO TX
835 PM CST SUN DEC 22 2002

SPC STILL HAS OUR CWFA IN THE SLIGHT RISK AREA FOR OVERNIGHT.  AREA
RADARS ALREADY SHOWING SHOWERS DEVELOPING IN THE WARM ADVECTION ZONE
FROM CORPUS CHRISTI NORTHWARD TO SAN ANTONIO AND BURNET.

LATEST MSAS ANALYSIS PLACED THE WARM FRONT ALONG THE TEXAS COAST
FROM GALVESTON TO CORPUS CHRISTI THEN INLAND TO SOUTH OF LAREDO.  AS
THE STRONG UPPER LOW CURRENTLY LOCATED OVER NORTHWEST MEXICO EJECTS
EASTWARD THE UVV WILL INCREASE NORTH OF THE WARM FRONT.  THIS WILL
RESULT IN ELEVATED CONVECTION ACROSS THE CWFA.  THIS CONVECTION WILL
HAVE THE POTENTIAL TO PRODUCE LARGE DAMAGING HAIL.

AS THE WARM FRONT MOVES NORTHWARD DURING THE EARLY MORNING HOURS
DEEP SURFACE BASED CONVECTION MAY DEVELOP SOUTH OF THE FRONTAL
BOUNDARY.  THERE IS THE POTENTIAL FOR ISOLATED TORNADOES WITH THIS
CONVECTION.  THIS MAY OCCUR ALONG THE MIDDLE AND UPPER TEXAS COAST
WITH SOME OF STORMS ALONG THE MIDDLE TEXAS COAST MOVING NORTHWARD
AFFECTING THE EXTREME EASTERN COUNTIES OF THE CWFA.

TIMING...THE ELEVATED CONVECTION IS EXPECTED TO BEGIN AFTER 09Z
(3AM) WITH DEEP CONVECTION POSSIBLE FOR THE EXTREME EASTERN COUNTIES
BY 12Z (6AM).

NO CHANGES TO CURRENT FCST.

13/04

...PREVIOUS DISCUSSION...
SEVERE WEATHER SCENARIO COMING TOGETHER FOR LATE TONIGHT AND
MONDAY.  INCREASING MOISTURE, MASSIVE DESTABILIZATION, WET BULB ZERO
HEIGHT LOWERING.  AS PER SPC DISCUSSION, WILL HAVE DAMAGE MAINLY
FROM HAIL IN SOUTH CENTRAL TEXAS.  CLOUDINESS ERODES TUESDAY IN TIME
FOR A MILD CHRISTMAS DAY.  BUT ANOTHER SERIES OF UPPER LOWS WILL
MOVE THROUGH THE NORTHERN HALF OF TEXAS BRINING A FEW BRIEF SNOW
FLURRIES AND SLEET WEDNESDAY NIGHT AND THURSDAY TO ALL BUT THE
EXTREME SOUTHWEST COUNTIES.  TEMPS WILL BE ON THE MILD SIDE  TONIGHT
AND MONDAY WITH THE WARM SECTOR MOVING INLAND BEFORE COLD AIR
ADVECTION STARTS LATER MONDAY AFTERNOON AND EVENING. FROM THERE
TEMPS GET COLDER WITH NIGHTTIME LOWS FREEZING IN THE HILL COUNTRY
AND NORTH OF I-1O EAST. DAYTIME HIGHS REMAIN BELOW NORMAL FROM
PASSING CLOUDS.  A DRIER NORTHWEST FLOW KICKS IN THURSDAY NIGHT
ALLOWING DAYTIME HIGHS TO RETURN TO NEAR NORMAL FRIDAY AND
SATURDAY.
STILL COLD AT NIGHT.

PRELIM NUMBERS...
AUS 52 63 41 52 30  6744
DRT 54 68 44 53 32  6543
SAT 57 69 43 53 33  6744

.EWX...NONE.

06/19/DC

TXZ171>173-183>194-202>209-217>225-228-231200-

HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE AUSTIN/SAN ANTONIO TX
548 AM CST SUN DEC 22 2002

THIS HAZARDOUS WEATHER OUTLOOK IS FOR SOUTH CENTRAL TEXAS.

.DAY ONE...TODAY AND TONIGHT
THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS LATE TONIGHT
INTO MONDAY AS AN UPPER LEVEL STORM SYSTEM MOVES THROUGH TEXAS. THESE
THUNDERSTORMS WILL BE CAPABLE OF PRODUCING LARGE HAIL...DAMAGING
WINDS AND TORNADOES. THE SLIGHT RISK AREA IS MAINLY OVER THE EASTERN
TWO-THIRDS OF SOUTH CENTRAL TEXAS OR GENERALLY ALONG AND EAST OF A
JUNCTION TO JOURDANTON LINE.

.DAYS TWO THROUGH SEVEN...
THERE REMAINS A CHANCE OF SEVERE THUNDERSTORMS MONDAY AS AN UPPER
LEVEL STORM SYSTEM MOVES THROUGH THE AREA.  THESE THUNDERSTORMS WILL
BE CAPABLE OF PRODUCING LARGE HAIL...DAMAGING WINDS AND TORNADOES.
OTHERWISE NO HAZARDOUS WEATHER IS EXPECTED THROUGH THE PERIOD.

.SPOTTER INFORMATION STATEMENT...
SPOTTER ACTIVATION MAY BE NEEDED LATE TONIGHT OR MONDAY.