[MCD] SWOMCD

[Mesoscale Convective Discussions]

ACUS11 KWNS 131625
SWOMCD
SPC MCD 131625 
TXZ000-131830-

MESOSCALE DISCUSSION 0050
NWS STORM PREDICTION CENTER NORMAN OK
1025 AM CST SAT JAN 13 2007

AREAS AFFECTED...SOUTH-CENTRAL TX

CONCERNING...SEVERE POTENTIAL...WATCH UNLIKELY 

VALID 131625Z - 131830Z

STRONG TSTMS WITH HEAVY RAIN WILL CONTINUE TO SPREAD ACROSS PARTS OF
TX HILL COUNTRY THROUGH NOON. RAINFALL RATES AROUND 1 INCH PER HOUR
COMBINED WITH POTENTIAL FOR REPEAT/TRAINING CELLS WILL CONTINUE TO
RESULT IN LOCALIZED FLOODING PROBLEMS. ADDITIONALLY... STRONGER
CELLS IN THE WARM SECTOR AND/OR NEAR THE SURFACE FRONT COULD PRODUCE
DAMAGING WINDS OR A TORNADO BEFORE CROSSING OVER THE BOUNDARY AND
MOVING NORTH ATOP STABLE SURFACE-BASED AIR MASS.

VERY SHARP SURFACE COLD FRONT ALONG A LINE FROM 10 SE CLL TO 40 SE
AUS TO 45 N HDO CONTINUES TO MAKE VERY SLOW SWD PROGRESS ACROSS THE
TX HILL COUNTRY LATE THIS MORNING. MOISTURE-LADEN LOW LEVEL JET
EMANATING FROM THE LOWER RIO GRANDE VALLEY AND THE WRN GULF OF
MEXICO HAS BEEN INTERSECTING THE SHARP FRONTAL SURFACE AND
CONTRIBUTING TO AN ACTIVE ZONE HEAVY TSTMS FROM SAN ANTONIO AREA TO
NORTH OF AUSTIN THIS MORNING. RECENT RADAR DATA INDICATES THAT A FEW
DISCRETE CELLS HAVE EXHIBITED UPDRAFT ROTATION DURING AND AFTER THE
TRANSITION ACROSS THE COLD FRONT WHERE LOW INTENSE LOW LEVEL SHEAR
IS INDICATED IN OBJECTIVE ANALYSIS DATA AND PROFILER WINDS. IF
PERSISTENT CELLS DEVELOPING IN THE WARM SECTOR CAN REMAIN
DISCRETE...A BRIEF WIND GUST OR TORNADO CANNOT BE RULED OUT AS THIS
ACTIVITY INTERACTS WITH THE FRONTAL ZONE. HOWEVER...LARGE SCALE
UPPER SUPPORT FOR DEEPER VERTICAL MOTION ACROSS THE REGION DOES
APPEAR LIMITED AT THIS TIME AND A WATCH IS NOT CURRENTLY EXPECTED.

HEAVY RAIN AND LOCALIZED FLOODING POTENTIAL ARE LIKELY TO PERSIST
ALONG AND NORTH OF THE FRONT INTO THE AFTERNOON. FOR THE TIME
BEING...THE ZONE OF STRONGER STORMS APPEARS TO HAVE SHIFTED WEST OF
I35 AND THIS SHOULD PROVIDE SOME RELIEF TO THE SAN MARCOS/AUSTIN
AREAS AFTER VERY HEAVY RAIN THIS MORNING. HOWEVER... PW VALUES IN
EXCESS OF 1.5 INCHES...AND POTENTIAL FOR REPEAT CONVECTION GENERATED
NEAR SLOW-MOVING FRONT AND THEN MOVING NWD WITHIN MEAN DEEP-LAYER
SSWLY FLOW...WILL CONTINUE TO RESULT IN COPIOUS RAINFALL AMOUNTS IN
THE POST-FRONTAL REGION ALONG THE I35 CORRIDOR.

..CARBIN.. 01/13/2007

...PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT...

ATTN...WFO...HGX...FWD...EWX...

30559834 31019804 31659757 31719668 31489648 30059697
29659727 29069769 28809819 28749864 29009887 29309896
29659890 30209859 

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