Quantitative Precipitation Forecast
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FOUS30 KWBC 282233
QPFERD

EXCESSIVE RAINFALL DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
632 PM EDT THU APR 28 2016

...VALID 01Z FRI APR 29 2016 - 12Z FRI APR 29 2016...
...REFERENCE AWIPS GRAPHIC UNDER...DAY 1 EXCESSIVE RAINFALL...


SLIGHT RISK OF RAINFALL EXCEEDING FFG TO THE RIGHT OF A LINE FROM
CTZ 20 ENE HBI 15 N TDF 10 S FKN 10 SSW MQI 40 W HSE 15 NNE OAJ
CTZ.

SLIGHT RISK OF RAINFALL EXCEEDING FFG TO THE RIGHT OF A LINE FROM
25 NE PKB 15 SSW 2G4 15 SW W99 10 W ROA HLX 10 E VJI 25 NW 6V3
10 E JKL 35 NNW JKL 45 SE ILN 25 NE PKB.

SLIGHT RISK OF RAINFALL EXCEEDING FFG TO THE RIGHT OF A LINE FROM
20 S SHV TRL 25 S DUC 15 SSE F05 60 S CDS 40 E PVW 40 SE AMA
10 W PPA 20 ENE HHF 30 SW JWG 15 E OUN 15 E RKR 10 NNE M89
15 NE ELD 30 S ELD 20 S SHV.


...SOUTHERN PLAINS...

A SLIGHT RISK REMAINS IN THE VICINITY OF THE WEST TO EAST ORIENTED
FRONTAL BOUNDARY FORECAST TO DRIFT NORTHWARD INTO THE THE RED
RIVER VALLEY AND ARKLATEX TONIGHT. RICH MOISTURE IS POISED TO MAKE
A QUICK RETURN INTO THIS AREA AS HEIGHT FALLS PULL OUT OF THE
ROCKIES...AND LOW LEVEL FLOW VEERS TO SOUTHERLY WHILE ACCELERATING
TO 25-40 KNOTS BY MORNING. AT 22Z WE NUDGED OR EXPANDED THE RISK
AREA NORTHWARD INTO MORE OF EASTERN OK AND SOUTHWEST AR...GIVEN
THE SIGNAL IN THE 12Z HI-RES GUIDANCE. IT ALSO APPEARS THAT THIS
PORTION OF THE EVENT WILL BE DOMINATED BY WARM ADVECTION...WHICH
DOES TEND TO ALLOW FOR MORE OF A NORTHWARD DRIFT...WITHOUT ANY
FOCUSED DEEP ASCENT CAPABLE OF CAUSING UPSCALE GROWTH AND AN
ANCHORING COLD POOL UNTIL PERHAPS NEAR OR BEYOND 12Z AND THE END
OF THIS OUTLOOK PERIOD.

FARTHER WEST...A SEPARATE MAXIMUM OF RAINFALL IS EXPECTED OVER THE
EASTERN TEXAS PANHANDLE...WHERE STRONGER UPPER DIFLUENCE OVERLAPS
WITH THE INSTABILITY GRADIENT AT THE WESTERN END OF THE LIFTING
SURFACE BOUNDARY. MODELS SUCH AS THE NSSL WRF AND GEM REGIONAL
SHOWED A PRONOUNCED MAXIMUM HERE...WITH STRONGLY BACKED LOW LEVEL
INFLOW AND INCREASINGLY DEEP MOISTURE LATER TONIGHT. A FLASH FLOOD
RISK MAY BECOME EVIDENT...ESPECIALLY AT THE SOUTHERN FLANK OF WHAT
COULD BE A SMALL MCS GIVEN THE INCREASING DEEP LAYER LIFT IN A
REGION OF SUFFICIENT AND IMPROVING INSTABILITY. THE RISK OF HEAVY
RAIN IS RELATIVELY LESS ACROSS PARTS OF WESTERN NORTH TEXAS AND
SOUTHWEST OKLAHOMA AROUND SPS-LAW...BUT WE DID CONNECT THE SLIGHT
RISK ACROSS THIS AREA. THERE IS AT LEAST SOME POTENTIAL FOR
PROPAGATION INTO THE INFLOW TO DISPLACE A RAINFALL MAXIMUM FARTHER
SOUTHEAST OUT OF THE PANHANDLE WITH TIME...AND THE MENTIONED AREA
SPS-LAW HAS SEEN RAINFALL THAT IS SEVERAL INCHES ABOVE AVERAGE
OVER THE PAST TWO WEEKS...MARKING THE AREA WITH WET ANTECEDENT
CONDITIONS.


...NORTHEAST NC...

STRONG CONVECTION WAS PLENTIFUL ACROSS SOUTHWEST VA AND WESTERN NC
EARLY THIS EVENING. SCATTERED TO NUMEROUS CELLS WILL ROLL THROUGH
AN AREA THAT RECEIVED HEAVY RAINFALL WITHIN THE PAST 24 HOURS.
FLASH FLOOD GUIDANCE VALUES ARE RELATIVELY LOWER...WITH 2 INCHES
IN AN HOUR OR 2.5 INCHES IN 3 HOURS ESTIMATED TO CAUSE BANKFUL
CONDITIONS. A FEW CELL MERGERS AND GROWTH OF SMALL SCALE OUTFLOWS
MAY LOCALLY BOOST RAINFALL AMOUNTS ABOVE FFG...BUT GENERALLY THE
DEEP WESTERLY FLOW IN PLACE SHOULD ENSURE FORWARD
PROGRESSION...AND WITH MANY OF THE STORMS REMAINING DISCRETE...THE
FLASH FLOOD RISK SHOULD REMAIN ISOLATED.


...UPPER OH VALLEY INTO THE CENTRAL APPALACHIANS...

FFG VALUES REMAIN LOW ACROSS THE UPPER OH VALLEY INTO THE CENTRAL
APPALACHIANS. WARM ADVECTION AND STRONG WESTERLY FLOW JUST NORTH
OF THE UPPER JET AXIS WILL SUPPORT ORGANIZED THUNDERSTORMS INTO
THE EARLY EVENING HOURS. REGIONAL RADARS ESTIMATED HOURLY RAIN
RATES EXCEEDING ONE INCH BENEATH THE STRONGER CORES AT 22Z. SUCH
RATES WILL LIKELY EXCEED THE VERY REACHABLE FFG VALUES IN THIS
AREA...ESPECIALLY WEST VIRGINIA...AND MAY CAUSE FLASH FLOODING IN
THE MOST SUSCEPTIBLE LOCATIONS. OVERALL...EXPECT A DECREASING
TREND BY 00-02Z WITH NOT ONLY THE LOSS OF HEATING...BUT THE UPPER
JET AXIS LIFTING NORTHWARD ONTO THE COOL SIDE OF THE INSTABILITY
GRADIENT.

BURKE
$$




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