Quantitative Precipitation Forecast
Issued by NWS

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FOUS30 KWBC 020727
QPFERD

EXCESSIVE RAINFALL DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
227 AM EST TUE FEB 02 2016

...VALID 12Z TUE FEB 02 2016 - 12Z WED FEB 03 2016...
...REFERENCE AWIPS GRAPHIC UNDER...DAY 1 EXCESSIVE RAINFALL...


SLIGHT RISK OF RAINFALL EXCEEDING FFG TO THE RIGHT OF A LINE FROM
15 S HTS 25 ENE JKL 30 WNW LNP 25 ENE OQT 10 SSW TYS RHP 1A5
20 W MRN 15 ENE FQD GMU 25 SW CEU PDK 20 SSE ANB 20 WNW MGM
45 NNE BFM 25 WNW MOB 30 NNW GPT 25 WSW PIB 35 E JAN 50 NW NMM
45 ENE GWO 40 N TUP 45 SW HOP 20 NE CKV 10 SSW FTK 15 WNW CVG
15 NNW SGH 20 NNW 4I3 ZZV 10 N 3I2 15 S HTS.


...OH/TN VALLEYS...GULF COAST STATES...SOUTHERN APPALACHIANS...

IN THE WARM SECTOR EAST OF THE LOW TRACK ACROSS THE MIDWEST AND
AHEAD OF AN ATTENDANT COLD FRONT...AN INCREASINGLY STRONG AND
MOIST LOW LEVEL JET IS EXPECTED TO BECOME ESTABLISHED ACROSS THE
GULF COAST STATES AND SURGING WELL NORTH INTO THE MID MS/OH AND TN
VALLEYS FROM MIDDAY THROUGH THE AFTERNOON. STRONG WARM ADVECTION
AND INCREASINGLY FAVORABLE MOISTURE/INSTABILITY PROFILES WILL
ALLOW CONVECTION TO DEVELOP AND EXPAND IN COVERAGE ALONG AND JUST
AHEAD OF THE COLD FRONT THROUGH THE AFTERNOON HOURS...INITIALLY
FOCUSED ON PARTS OF THE LOWER/MID
MS VALLEY...BUT THEN BECOMING INCREASINGLY MORE ORGANIZED FARTHER
EAST BY LATER TODAY ACROSS THE OH/TN VALLEYS AND DOWN TO THE
CENTRL GULF COAST.

IN FACT...THE GFS AND ECMWF INDICATE THE LOW LEVEL JET INCREASING
TO 50 TO 60 KTS ACROSS THE OH/TN VALLEYS BY LATE THIS AFTERNOON
WITH A NOSE OF 1.5 INCH PWATS SURGING NORTH FROM THE GULF OF
MEXICO. GIVEN THE STRONG SHEAR PROFILES AND STRONG ASCENT IN THE
WARM SECTOR AHEAD OF THE MID LEVEL TROUGH/COLD FRONT...IT IS
EXPECTED THAT CONVECTION ACROSS THE OH/TN VALLEYS AND PARTS OF THE
GULF COAST STATES WILL BE HIGHLY ORGANIZED...AND WHILE THE
CONVECTIVE MODE WILL INITIALLY BE SEVERE IN NATURE...THE
CONVECTION SHOULD ESSENTIALLY MORPH INTO MULTIPLE ORGANIZED BANDS
LATER THIS AFTERNOON AND EVENING THROUGH CELL-MERGERS AND
BACKBUILDING CELLS...AND RESULTING IN POTENTIALLY A COUPLE OF QLCS
STRUCTURES. THERE ARE CONCERNS FOR VERY HEAVY RAINFALL WITHIN
THESE MORE ORGANIZED BANDS AND ESPECIALLY WITH THE LIKELIHOOD OF
CELL-MERGERS AND SOME TRAINING CELLS. THE HIRES GUIDANCE LED BY
THE WRF-ARW...WRF-NMMB AND NSSL-WRF ALL SHOW MULTIPLE LINEAR BANDS
OF ENHANCED RAINFALL SUGGESTING AN ELEVATED RISK OF TRAINING
CELLS. WPC WILL FAVOR THIS SCENARIO THROUGH THE AFTERNOON AND
EVENING HOURS. THIS WILL RESULT IN HEAVY RAINS OVER PARTS OF OH
AND TN VALLEY FALLING ON SATURATED GROUND GIVEN RECENT SNOW-MELT
AND WET ANTECEDENT CONDITIONS. RAINFALL AMOUNTS OF 1 TO 3 INCHES
WILL BE EXPECTED...WITH SOME ISOLATED HEAVIER AMOUNTS WHERE ANY
TRAINING OCCURS. THE THREAT TO THE GULF COAST STATES IS MORE TIED
INTO HIGHER PWATS GENERATING HEAVIER RAINFALL RATES...AND THE
THREAT TO THE SOUTHERN APPALACHIANS IS ASSOCIATED WITH ENHANCED
SOUTH/SOUTHWEST FLOW INTO THE HIGHER TERRAIN WHICH WILL ENHANCE
UPSLOPE SHOWER ACTIVITY. WILL BE CLOSELY MONITORING THE RISK OF
FLASH FLOODING LATER THIS AFTERNOON AND EVENING ACROSS ALL THESE
AREAS.

ORRISON
$$




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