Quantitative Precipitation Forecast
Issued by NWS

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FOUS30 KWBC 281412
QPFERD

EXCESSIVE RAINFALL DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
1011 AM EDT THU AUG 28 2014

...VALID 15Z THU AUG 28 2014 - 12Z FRI AUG 29 2014...
...REFERENCE AWIPS GRAPHIC UNDER...DAY 1 EXCESSIVE RAINFALL...


SLIGHT RISK OF RAINFALL EXCEEDING FFG TO THE RIGHT OF A LINE FROM
10 NW OVS 30 E TNU CNC 20 WNW STJ 25 NE MHK 20 N MHK 40 N MHK
25 W FNB 10 W RDK 15 W CAV OWA 20 W LUM 20 NNE RCX EGV 10 NW OVS.


1400 UTC UPDATE

UPPER MS VALLEY

THE PREVIOUS EXCESSIVE RAINFALL POTENTIAL OUTLOOK ACROSS PORTIONS
OF THE CENTRAL PLAINS INTO THE UPPER MS VALLEY HAS BEEN NARROWED
TO REFLECT THE CURRENT EVOLUTION TO THE ORGANIZED CONVECTION
ASSOCIATED WITH THE NORTHEASTWARD MOVING MCV.  WITH THE CURRENT
WEAKENING TREND TO THE CONVECTION---AS PER WARMING CLOUD TOPS ON
LATEST SATELLITE IMAGERY---THE EXCESSIVE RAINFALL THREAT IS
DIMINISHING.  THIS AND INCREASED PROGRESSION OF THE MCV HAS
ALLOWED FOR THE WESTERN PORTION OF THE THREAT REGION TO BE TRIMMED
EASTWARD AND THE MODERATE RISK AREA TO BE TAKEN OUT.  THERE STILL
IS POTENTIAL FOR TRAINING OF CELLS IN A SOUTHWEST TO NORTHEASTERLY
DIRECTION ON THE SOUTHEAST SIDE OF THIS MCV IN THE MOIST SOUTH
SOUTHWEST TO SOUTHWESTERLY LOW LEVEL FLOW FROM FAR NORTHEAST
KS---ACROSS FAR NORTHWEST MO AND INTO CENTRAL IA AND EVENTUALLY
FARTHER TO THE NORTHEAST INTO SOUTHEAST MN AND NORTH CENTRAL WI.
IN AREAS OF TRAINING---ISOLATED 1-2" RAINFALL AMOUNTS IN AN HOUR
POSSIBLE.

TX GULF COAST INTO THE SOUTHWEST LA GULF COAST

VERY HEAVY TO ISOLATED EXCESSIVE RAINFALL AMOUNTS POSSIBLE ALONG
THE UPPER TX GULF COAST INTO THE SOUTHWEST LA COAT.  SURFACE
ANALYSIS THIS MORNING SHOWS A WEAK LOW OFF THE SOUTH TX
COAST--WITH A INVERTED TROF EXTENDING NORTHWARD ALONG THE TX GULF
COAST.  CONVECTION HAS ENHANCED IN THE LOW LEVEL SOUTHEASTERLY
FLOW CONVERGING INTO THIS COASTAL TROF.  NOT A LOT OF CONFIDENCE
IN HOW ANY INDIVIDUAL RAIN BANDS IN THIS SOUTHEAST FLOW WILL
EVOLVE---BUT WHERE THEY DO SET UP FROM THE CENTRAL TO UPPER TX
COAST INTO COASTAL SOUTHWEST LA---PRECIPITATION TOTALS OF 1-3" IN
AN HOUR OR TWO POSSIBLE.

ORAVEC


PREVIOUS DISCUSSION

ONGOING CONVECTION EARLY THU MORNING FROM THE WESTERN HIGH PLAINS
TO THE LEE OF THE CENTRAL ROCKIES EAST NORTHEASTWARD INTO THE
CENTRAL PLAINS WILL CONTINUE TO SPREAD NORTH AND EAST THROUGHOUT
THE DAY AND EVENTUALLY REACH PARTS OF THE WESTERN GREAT LAKES BY
THU NIGHT/EARLY FRIDAY MORNING.  THE PCPN WILL BE ASSOCIATED WITH
THE EAST NORTHEASTWARD PUSH OF THE GREAT BASIN CLOSED LOW AND
HEIGHT FALLS AHEAD OF THIS CLOSED LOW.  LOW LEVEL INFLOW INTO THE
INITIALLY WEST TO EAST ORIENTED FRONTAL BOUNDARY ACROSS THESE
AREAS---AND ENHANCED UVVS FROM UPPER DIFFLUENCE AHEAD OF THE
AFOREMENTIONED HEIGHT FALLS---WILL SUPPORT ADDITIONAL ORGANIZED
CONVECTION IN THE AXIS OF ABOVE AVERAGE PW VALUES---2-2.5 STANDARD
DEVIATIONS ABOVE THE MEAN FORECAST TO PERSIST ALONG AND NORTH OF
THIS FRONT.  HEAVY TO LOCALLY EXCESSIVE PRECIPITATION TOTALS ARE
POSSIBLE...WITH THE BEST RISK OF EXCESSIVE RAINFALL OCCURRING OVER
PARTS OF EASTERN NEBRASKA INTO SOUTHWEST IA THROUGH MUCH OF THE
MORNING SINCE THE STRONGEST MID/UPPER LEVEL
DIFFLUENCE/DIVERGENCE...BEST LOW LEVEL JET AND MOISTURE TRANSPORT
WILL BE LOCATED IN A REGION WHERE FLASH FLOOD GUIDANCE VALUES WERE
LOW FROM RECENT RAINS.  THE SLIGHT AND MDT RISK AREAS MAINTAINED A
FAIR DEGREE OF CONTINUITY FROM THE PREVIOUS OUTLOOK.

FOR FURTHER DETAILS REGARDING ANY ACTIVE MESOSCALE PRECIPITATION
DISCUSSIONS (MPD) WITHIN THE EXCESSIVE RAINFALL OUTLOOK AREA...
PLEASE REFER TO THE LINK FROM THE WPC HOME PAGE ABOVE THE TOP NEWS
OF THE DAY... OR GO DIRECTLY TO THE MPD PAGE:
WWW.WPC.NCEP.NOAA.GOV/METWATCH/METWATCH_MPD.PHP.

BANN

$$





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