MESO: Nws Weather Prediction Center College Park Md

AWUS01 KWNH 140302
FFGMPD
TXZ000-140700-

MESOSCALE PRECIPITATION DISCUSSION 0279
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
1101 PM EDT SUN OCT 13 2013

AREAS AFFECTED...CENTRAL TX

CONCERNING...HEAVY RAINFALL...FLASH FLOODING POSSIBLE

VALID 140300Z - 140700Z

SUMMARY...A SLOW-MOVING MCS WILL BE ADVANCING GRADUALLY INTO AREAS
ALREADY IMPACTED BY HEAVY RAINS EARLIER IN THE DAY...WHICH MAY
PRODUCE SOME ADDITIONAL FLASH FLOOD CONCERNS AT LEAST LOCALLY.

DISCUSSION...A DYNAMICALLY FORCED COLD-TOPPED MCS INVOF A STALLED
OUT FRONTAL ZONE IS MOVING SLOWLY EASTWARD OUT OF WEST-CENTRAL TX.
THE LATEST IR/WV IMAGERY SHOWS VERY DIV FLOW ALOFT ASSOCD WITH H25
RRQ JET DYNAMICS AND RELATED OUTFLOW FROM T.S. OCTAVE IN THE E PAC
SOUTH OF MEXICO. RATHER DEEP MOISTURE IS IN PLACE TOO GIVEN A
COMBINATION OF SELY LOW LEVEL FLOW OFF THE GULF OF MEXICO...AND
SWLY MID/UPR LEVEL FLOW EMANATING FROM THE E PAC WITH T.S. OCTAVE
AND CROSSING MAINLAND MEXICO INTO THE SOUTHERN PLAINS.

THE THERMODYNAMIC ENVIRONMENT ACROSS THIS REGION HOWEVER IS NOT
PARTICULARLY FAVORABLE WITH MUCAPE VALUES AT BEST BETWEEN 250 TO
500 J/KG INVOF THIS ACTIVITY AND EVEN DOWNSTREAM ACROSS THE TX
HILL COUNTRY. THE PERSISTENT MCS FARTHER SOUTHEAST ADJACENT THE
RIO GRANDE RIVER IS HELPING TO SIGNIFICANTLY INTERCEPT AT LEAST
THE STRONGER LOW LEVEL MOISTURE/INSTABILITY TRANSPORT INTO CNTRL
TX. WHILE QUESTIONS INVOLVING THE THERMODYNAMIC ENVIRONMENT WILL
PERSIST IN THE SHORT-TERM...THE FORCED CONVECTIVE ENVIRONMENT
SHOULD TEND TO PERSIST. IT SHOULD BE NOTED THAT THE GLOBAL MODELS
INCLUDING THE 12Z ECMWF AND 18Z GFS FAVOR AN INCREASE IN THE SELY
LOW LEVEL JET OVER THE REGION OVERNIGHT WHICH WILL AT LEAST
ATTEMPT TO PROVIDE STRONGER THERMODYNAMICS FOR SUSTAINABLE
CONVECTION. SO THIS WILL BE MONITORED.

SINCE THIS MCS WILL BE APPROACHING AREAS HIT HARD EARLIER IN THE
DAY WITH HEAVY RAINFALL...THERE WILL AT LEAST BE SOME ADDITIONAL
SHORT-TERM CONCERNS FOR FLASH FLOODING.

ORRISON

...PLEASE SEE WWW.WPC.NCEP.NOAA.GOV FOR GRAPHIC PRODUCT...

ATTN...WFO...FWD...SJT...MAF...

ATTN...RFC...WGRFC...

LAT...LON 31180232 31740155 32200088 32159992 31949914 31469881
30879902 30499968 30420066 30630192 31180232

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