Quantitative Precipitation Forecast
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FOUS30 KWBC 170111
QPFERD

EXCESSIVE RAINFALL DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
910 PM EDT THU APR 16 2015

...VALID 03Z FRI APR 17 2015 - 00Z SAT APR 18 2015...
...REFERENCE AWIPS GRAPHIC UNDER...DAY 1 EXCESSIVE RAINFALL...


SLIGHT RISK OF RAINFALL EXCEEDING FFG TO THE RIGHT OF A LINE FROM
20 SSW MGM 30 N DHN 10 NW BGE 10 S MAI 25 SSE NPA 35 NNE CYD
GSM 15 NE KBBF 25 NW ALI 25 NNW COT HDO 15 WSW 62H 35 E UTS
15 SSE AEX 40 WNW PIB 45 ESE NMM 20 SSW MGM.


...GULF COAST STATES...

THREAT OF PSBL EXCESSIVE RAINS REMAINS ACRS A LARGE PORTION OF THE
GULF COAST REGION AS VERY RICH ARIMAS WITH PWS FROM BETWEEN 1.75
AND 2 INCHES ACRS THE CNTL/WRN GULF IS TAPPED BY INCREASINGLY
DIFFLUENT JET STRUCTURE DVLPG EWD FROM THE SRN PLAINS WITH VERY
ENERGETIC SUBTROP JET ACRS NRN MEX.  RADAR AT 00Z  SHOWED
EXTENSIVE AREA OF CNTVN ACRS EAST TEX INTO SRN LA AND PARTS OF MS.
  ONE PARTICULARLY STG BAND OF STORMS WITH SLOW MOVING CONVECTION
WAS ANCHORED ALONG WRN PORTION OF OUTFLOW BNDRY FROM WEAK BUBBLE
HIGH OVER SRN LA WHICH MAY BE MAINTAINED THRU THE EARLY EVENING
HOURS AS MOIST 85H S/SELY 85H FLOW INTERSECTS THIS AREA. MODELS DO
SHOW A WEAKENING OF THE JET OVERNIGHT...BUT AT LEAST SOME
SEMBLANCE OF UPR DIFFLUENCE REMAINS WHICH ALONG WITH BROAD LOW
LEVEL WAA COULD HELP MAINTAIN CNVTV HEAVY RAIN THREAT NEAR THE UPR
TX AND LA COASTS.

ADDITIONAL STORMS MAY ORGANIZE BACK WEST WITH TIME AS A LARGE
UPPER TROUGH LEANS INTO TEXAS. DIFLUENT MID LEVELS WILL COMBINE
WITH AN INCREASING AXIS OF MOISTURE/INSTABILITY TO PRODUCE GREATER
COVERAGE AND ORGANIZATION OF THUNDERSTORMS PRODUCING HEAVY RAIN
OVER THE TEXAS HILL COUNTRY TO THE UPPER TX COAST LATE TONIGHT AND
ESPECIALLY ON FRIDAY. PRECIPITABLE WATER VALUES WILL BE SOMEWHAT
ANOMALOUS...AND HEAVY RAIN RATES ARE EXPECTED...BUT OF GREATER
CONCERN WOULD BE THE POTENTIAL FOR REPEATED ROUNDS OF CONVECTION
SHOULD THE AXIS OF DEEPER MOISTURE...ORIENTED GENERALLY WEST TO
EAST...BECOME REINFORCED BY THUNDERSTORM OUTFLOWS...PRODUCING A
STRONGER LOW LEVEL FOCUS FOR REDEVELOPMENT AHEAD OF THE SLOW
MOVING UPPER TROUGH.

SRN NEBRASKSA SWD INTO WRN OK...

SOME INCREASING CONCERN FOR SOME SHORT TERM TRAINING OF DVLPG N/S
CONVECTIVE LINES ACRS THIS REGION OVERNIGHT INTO FRI IN ADVANCE OF
DEEP UPR LOW OVER THE CNTL ROCKIES. LOW LEVELS HAVE BECOME
INCREASINGLY MOIST INTO INVERTED TROF AXIS FROM WRN OK INTO SRN KS
WITH SFC DPS INTO THE MID 60S.  WHILE THE DEEPER MSTR REMAINS
FARTHER EAST...THE SUSTAINED SELY LOW LEVEL FLOW SHOULD MAINTAIN
GOOD CONVERGENCE AND LOW LEVEL MSTR INTO THE BNDRY.  MODEST CAPE
OF 1500 J/KG WAS INDICATED ACRS CNTL OK WHICH SHOULD CONTINUE TO
FUEL STG TSTMS..UNDER DIFFLUENT FLOW ALOFT.  COULD SEE SOME LOCAL
RAINFALL RATES HERE OF 2+ INCHES IN A FEW HOURS WITH ISOLD HEAVIER
AMOUNTS WHERE STGR CELL TRAINING OCCURS. WHILE MOST FFG VALUES ARE
RELATIVELY HIGH HERE...COULD NOT RULE OUT ISOLD RUNOFF PROBLEMS
DVLPG.

BURKE/SULLIVAN
$$




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