Quantitative Precipitation Forecast
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000
FOUS30 KWBC 151402
QPFERD

EXCESSIVE RAINFALL DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
1002 AM EDT WED APR 15 2015

...VALID 15Z WED APR 15 2015 - 12Z THU APR 16 2015...
...REFERENCE AWIPS GRAPHIC UNDER...DAY 1 EXCESSIVE RAINFALL...


SLIGHT RISK OF RAINFALL EXCEEDING FFG TO THE RIGHT OF A LINE FROM
20 NE DNL MMT 30 W MYR 35 SE MYR 75 SSE MYR 95 SE CHS 80 SE HXD
30 E SSI 30 E AMG 15 NW VDI 30 S HQU 20 NE DNL.

SLIGHT RISK OF RAINFALL EXCEEDING FFG TO THE RIGHT OF A LINE FROM
10 NNW S58 20 SW P92 7R4 ARA 25 S BTR 10 NNE ASD 15 NNW GPT
35 WSW GZH 40 W OZR 20 SW OZR 30 E CEW 10 SSW CEW 25 S JKA
35 SSW KMIS 10 NNW S58.


...SC / GA / SAVANNAH VALLEY...

AN ORGANIZED CONVECTIVE EVENT IS LIKELY DURING THE AFTERNOON
HOURS...SQUEEZED BETWEEN A SINKING FRONTAL BOUNDARY...THE SEA
BREEZE...AND AN APPROACHING 700 MB TROUGH. MOISTURE IS
PLENTIFUL...WITH PW VALUES OF 1.5 TO 1.7 INCHES REPRESENTING ABOUT
2.5 STANDARD DEVIATIONS FROM CLIMATOLOGY. MODERATE INSTABILITY AND
DEEP LAYER WIND SHEAR OF 15-25 KNOTS SHOULD BE SUFFICIENT FOR
ORGANIZED MULTICELLS AND PERHAPS BRIEF SUPERCELL CHARACTER...WHICH
WOULD LEAD TO SOME TRAINING AND/OR SLOW DEVIANT MOTION. ALTHOUGH
THE RISK AREA FOR HEAVY RAINFALL IS LIMITED IN SIZE...THE MODELS
SHOW STRONG AGREEMENT HERE...NOTING CONSISTENCY IN CONSECUTIVE
HRRR RUNS AND A LOCAL MAXIMUM FROM OUR IN-HOUSE ENSEMBLE WHICH
TAKES INTO ACCOUNT THE GLOBAL MODELS AND SREF MEMBERS. FLASH FLOOD
GUIDANCE VALUES ARE HIGH...AND MAY BE DIFFICULT TO BREACH...BUT
GIVEN THE VERTICAL MOISTURE PROFILES AND OPPORTUNITY FOR FOCUS
ALONG BOUNDARIES...SOME ISOLATED LOCATIONS COULD SEE EXCESSIVE
RAINFALL AND FLASH FLOODING. THE RISK WILL LIKELY DIMINISH BY
EVENING WHEN INSTABILITY EITHER BECOMES CONSUMED OR DECREASES
OWING TO COOLING.


...CENTRAL GULF COAST INTO THE FL PANHANDLE...

PRECIPITABLE WATER VALUES ABOVE AVERAGE FOR THE TIME OF
YEAR...UPWARD OF TO 2 TO 2.5 STANDARD DEVIATIONS...ARE EXPECTED TO
PERSIST ALONG THE GULF COAST.  WHILE FORCING FOR ASCENT WILL NOT
BE AS ORGANIZED AS IN PREVIOUS DAYS...THERE IS A MODEL SIGNAL FOR
ADDITIONAL CONVECTION/HEAVY RAINS AS UPWARD VERTICAL VELOCITIES
ARE ENHANCED AHEAD OF AN UPPER DIFFLUENCE MAXIMUM ASSOCIATED WITH
A SHORTWAVE SKIRTING THE CENTRAL GULF COAST THIS AFTERNOON.  WITH
RECENT HEAVY RAINS HAVING LOWERED FFG VALUES THERE WILL CONTINUE
TO BE A RISK OF ADDITIONAL RUNOFF ISSUES WEDNESDAY FROM SHORT TERM
PRECIP TOTALS OF 1"+ ACROSS THE CENTRAL GULF COAST INTO THE FL
PANHANDLE REGION.

BURKE/ORAVEC
$$





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