Quantitative Precipitation Forecast
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000
FOUS30 KWBC 281438
QPFERD

EXCESSIVE RAINFALL DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
1038 AM EDT TUE MAR 28 2017

...VALID 15Z TUE MAR 28 2017 - 12Z WED MAR 29 2017...
...REFERENCE AWIPS GRAPHIC UNDER...DAY 1 EXCESSIVE RAINFALL...


MARGINAL RISK OF RAINFALL EXCEEDING FFG TO THE RIGHT OF A LINE FROM
20 NNE JSV 30 WNW DEQ 10 S SLR 15 WNW CRS 15 ESE ACT 10 WNW GTU
15 NNW T82 35 SE SJT 30 NNE SJT 45 NNE SWW 60 S CDS 30 SW CDS
30 E PVW 30 ENE PVW 15 NW PVW 40 WNW PVW 40 ENE CVN 40 W AMA
25 SSE DHT DHT 25 NE CAO 35 ESE TAD 15 SE TAD 35 S PUB PUB
25 E COS LIC 10 WNW ITR 55 ESE GLD 25 SSE HLC 25 NW SLN 30 W EMP
PPF 20 SW GMJ 20 NNE JSV.

SLIGHT RISK OF RAINFALL EXCEEDING FFG TO THE RIGHT OF A LINE FROM
30 SE MLC 20 WNW SLR 10 NNW HQZ 10 WSW AFW 10 W MWL 40 NNW 7F9
30 NE ABI 45 SSW F05 25 NE CDS 30 WSW CSM 15 NNE CSM 25 SE JWG
SWO TUL 10 W MKO 30 SE MLC.


1500 UTC UPDATE

THE ONLY CHANGE MADE TO THE PREVIOUS EXCESSIVE RAINFALL POTENTIAL
OUTLOOK WAS TO EXPAND THE MARGINAL RISK AREA WESTWARD INTO THE TX
PANHANDLE TO COVER THE DEVELOPING CONVECTION ACROSS THIS REGION.
ALL OF THE HI RES GUIDANCE---INCLUDING THE LATEST HRRR---ARE
SLOW---1 TO 2 HOURS---TO DEVELOP THIS ACTIVITY WHEN COMPARING
THEIR SIMULATED RADARS TO CURRENT RADAR.  THIS SEEMS TO BE A
TYPICAL ERROR WITH CONVECTIVE DEVELOPMENT SEEN IN THE HI RES
GUIDANCE.  ONCE CONVECTION DOES FORM IN THE HI RES
GUIDANCE---HOURLY PRECIP RATES OF .50-.75" ARE DEPICTED OVER THE
TX PANHANDLE.  THESE RATES SEEM REASONABLE GIVEN LATEST RADAR
ESTIMATES---ALBEIT THEY ARE OCCURRING 1 TO 2 HOURS EARLIER THAN
MODELS FORECAST.

ORAVEC

...S-CENTRAL PLAINS...

IT REMAINS THE CASE THAT STRONG JET ENERGY DIVING INTO THE
BACKSIDE OF THE FULL-LATITUDE TROUGH NOW MOVING THROUGH THE
INTERMOUNTAIN WEST WILL ALLOW THIS SYSTEM TO AMPLIFY CONSIDERABLY
AS IT REACHES THE ROCKIES...PARTICULARLY ACROSS THE 4 CORNERS AND
SOUTHERN ROCKIES WHERE THE MORE VIGOROUS SOUTHERN STREAM COMPONENT
WILL LEAD TO A DEEPENING CLOSED LOW THAT SUBSEQUENTLY TRACKS
STEADILY INTO THE S-CENTRAL HIGH PLAINS LATER DAY1. THE ENSUING
LEE-SIDE CYCLOGENESIS WILL LEAD TO AN ELONGATED STRIPE OF
MOD-HEAVY PCPN ASSOCIATED WITH THE WARM CONVEYOR BELT AND
EVOLVING/EXPANDING CCB/DEFORMATION AND DEEPENING TROWAL. LEAD
POTENT LLJ MOISTURE INFLOW UP THROUGH THE SRN PLAINS WITH SYSTEM
DEVELOPMENT SUGGESTS CONDITIONS FAVORABLE FOR AN EXCESSIVE
RAINFALL THREAT. CONVECTIVE DEVELOPMENT AND OVERALL TRANSLATION
REMAINS UNCERTAIN AND POTENTIALLY PROGRESSIVE WITH MESO COLD POOL
DEVELOPMENTS...BUT DEEPEST AND MOST ANOMALOUS MOISTURE (PWS UP TO
1.5") AND HEIGHT FALLS/INSTABILITY SEEMS TO COMBINE/FOCUS MOST
OVER S-CENTRAL OK AND NRN TX...ESPECIALLY WITH CELL MERGERS. WPC
PROGS HAVE TRENDED HEAVIEST QPF UPWARDS TO 3-5" LOCALLY
THERE...WITH MORE MODERATE TO HEAVY AMOUNTS WRAPPED UP ACROSS THE
CENTRAL PLAINS. THIS SCENARIO IS MORE SUPPORTED NOW BY WELL
CLUSTERED 00 UTC ARW/NMMB/WRF NSSL/NAM CONEST GUIDANCE AND FITS
WELL WITH THE CURRENT SPC SEVERE THREAT AREAS.

SCHICHTEL
$$





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