Severe Thunderstorm Warning 122, NWS Austin/San Antonio, TX

SOUTH CENTRAL TEXAS FORECAST DISCUSSION
NATIONAL WEATHER SERVICE AUSTIN/SAN ANTONIO TX
315 AM CST MON DEC 23 2002

ONE OF THE MORE SIGNIFICANT TORNADO/SEVERE WEATHER THREATS OF THE
YEAR FOR SOUTH CENTRAL TEXAS COMES TWO DAYS BEFORE CHRISTMAS. THE
WESTERN TWO-THIRDS OF SOUTH CENTRAL TEXAS CAN EXPECT A WET MORNING
WITH ISOLATED SEVERE STORMS TO CREATE A SHOPPING HAZARD. A MORE
OMINOUS THREAT EXISTS EAST OF THE I-35 CORRIDOR WHERE DAYTIME
HEATING WILL ENHANCE THE SEVERE WEATHER THREAT INTO A THEAT FOR
SUPERCELLS AND TORNADOES.

IF IT WERE NOT FOR THE MORNING STREAMER CELL SPEEDS OF AROUND 30
TO 35 MPH, WOULD BE CONCERNED OF A FLASH FLOOD THREAT. SOILS REMAIN
NEARLY SATURATED FROM PREVIOUS RAINS, BUT WITH PRECIPITABLE WATER
VALUES HOLDING BELOW 1.5 FOR THE MOST PART, EXPECT ONLY THREAT OF
SUSTAINED HEAVY RAINS TO BE IN THE PATHS OF ANY SUPERCELLS THAT
DEVELOP OVER THE SOUTHEASTERN COUNTIES LATER TODAY. WILL MENTION
LOCALLY HEAVY RAINFALL FOR THE EASTERN TWO-THIRDS WITH SEVERE
WORDING MENTIONED AREA-WIDE.

WITH 06Z SATELLITE TRENDS SHOWING A SLIGHT EASTWARD POSITION OF THE
UPPER LOW CENTER COMPARED TO FORECAST AND A PAIRED JET PATTERN
INDICATING DEEPENING OVER CENTRAL TEXAS FOR THE NEXT 12 HOURS, THE
QPF TRENDS WILL PROBABLY BE A BIT AHEAD OF THE ALREADY FASTER GFS.
RAINFALL INTENSITIES ARE STEADILY INCREASING IN RESPONSE TO THE LOW
LEVEL JET OVER THE CENTRAL COUNTIES.

WITH A NEAR SOLID AREA OF RAIN EXPECTED OVER THE CENTRAL PORTIONS
HALF OF THE FORECAST AREA BY AROUND DAYBREAK, WILL CALL FOR HIGH
POPS OF 80 TO 100 PERCENT OVER THE EASTERN TWO-THIRDS. HELICITIES
COULD APPROACH 500 M2S2 OVER THE SOUTHEASTERN COUNTIES TOWARD NOON
ACCORDING TO THE RUC WITH 1500 J/KG OR GREATER CAPES, THE THREAT
FOR SEVERE WEATHER AND TORNADOES NEEDS TO BE WORDED STRONGLY HERE.
FOR WESTERN SECTIONS, WILL KEEP POPS IN THE 50-60 PERCENT RANGE WITH
SEVERE WORDING THROUGH THE AFTERNOON. DAYTIME HEATING COULD TRIGGER
A FEW HAILSTORMS DESPITE A GOOD DRY PUNCH ENTERING WEST TX.

WITH THE FASTER SPEED, WILL PLAN ON LESS MOISTURE BEING AVAILABLE
WHEN THE BASE OF THE TROUGH LIFTS ACROSS THE FORECAST AREA TUESDAY.
WILL TRIM POPS TO A SLIGHT CHANCE NORTHEAST.

OTHERWISE A WARM AND DRY ZONAL PATTERN WILL RESUME AGAIN FOR THE
NEXT SEVERAL DAYS UNTIL THE GFS AND NOGAPS DEPICT ANOTHER VIGOROUS
STORM SYSTEM THREATENING THE SOUTHERN PLAINS EARLY NEXT WEEK. A WEAK
SHORTWAVE MOVES THROUGH MAINLY NORTH TEXAS THURSDAY, BUT THE AIR
SHOULD BE TOO DRY TO SUPPORT MEASURABLE RAINS OVER SOUTH CENTRAL
TEXAS.

PRELIMINARY NUMBERS...
AUS 066/041/052/030/057 +5200
DRT 071/043/056/034/061 52-00
SAT 071/042/057/035/059 +4-00

.EWX...NONE.

18/3/PM

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.