Quantitative Precipitation Forecast
Issued by NWS

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FOUS30 KWBC 261428
QPFERD

EXCESSIVE RAINFALL DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
928 AM EST SUN FEB 26 2017

...VALID 15Z SUN FEB 26 2017 - 12Z MON FEB 27 2017...
...REFERENCE AWIPS GRAPHIC UNDER...DAY 1 EXCESSIVE RAINFALL...



1500 UTC UPDATE

NO CHANGES TO THE PREVIOUS EXCESSIVE RAINFALL POTENTIAL OUTLOOK.

ORAVEC

...EASTERN TEXAS / NORTHWEST LOUISIANA / SOUTHERN ARKANSAS...

THE COLUMN WAS QUITE DRY OVER THE SOUTHERN U.S. AND THE GULF AS OF
EARLY SUNDAY MORNING PER SOUNDINGS AND WATER VAPOR IMAGERY.
STILL...INCREASING LOW LEVEL FLOW AND UNSEASONABLY WARM GULF
WATERS WILL CERTAINLY CONTRIBUTE TO NORTHWARD MOISTURE
TRANSPORT...AND AN INSTABILITY AXIS IS FORECAST TO GROW IN
MAGNITUDE ALONG THE I-35 CORRIDOR OF TEXAS SUNDAY AFTERNOON.
COVERAGE OF SHOWERS AND THUNDERSTORMS SHOULD INCREASE SUNDAY
EVENING AND OVERNIGHT WITHIN AN UPPER JET CIRCULATION OVER
EASTERN/SOUTHERN ARKANSAS...AND STRETCHING BACK INTO A REGION OF
MODERATE ISENTROPIC UPGLIDE OVER EAST TEXAS. INSTABILITY AND
PRECIPITATION INTENSITY SHOULD PROVE TO BE GREATEST WITH WESTWARD
EXTENT. THIS RAISES THE POSSIBILITY OF HEAVY RAIN RATES...BUT WE
ESTIMATE THAT THE PROBABILITY OF FLASH FLOODING AND/OR RAINFALL
EXCEEDING FLASH FLOOD GUIDANCE IS STILL A LITTLE LESS THAN
REQUIRED FOR INTRODUCTION OF A MARGINAL RISK CONTOUR.

PRECIPITABLE WATER RECOVERS ONLY TO AROUND 1.00 TO 1.20
INCHES...AND SHARP VEERING SUGGESTS MATURE ECHOES / LINE SEGMENTS
WILL PROPAGATE QUICKLY EASTWARD AT AN ANGLE TO THE MEAN STORM
MOTION FOR INDIVIDUAL CELLS...WHEN COMPARING CORFIDI VECTORS TO
THE 0-6 KM WIND. WHEN COMBINED WITH THE FACT THAT MOST CONVECTION
WILL BE AT LEAST SOMEWHAT ELEVATED...IT APPEARS TRAINING WILL NOT
BE ESPECIALLY FAVORED. THE HI-RES MODELS GENERALLY TRENDED WETTER
ON THE 00Z CYCLE...AND DO ADVERTISE LOCAL SWATHS OF HEAVIER
RAINFALL...BUT PLACEMENT HAS BEEN INCONSISTENT IN THE MODELS.
SYNOPTIC INFLUENCES WOULD SUGGEST IF THERE ARE ANY HEAVY RAIN
ISSUES THEY WILL OCCUR FROM NORTHEAST TX INTO NORTHWEST LA AND
SOUTHERN AR...WHERE FLASH FLOOD GUIDANCE VALUES ARE QUITE HIGH.

BURKE
$$





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