Quantitative Precipitation Forecast
Issued by NWS

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FOUS30 KWBC 291855
QPFERD

EXCESSIVE RAINFALL DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
255 PM EDT FRI AUG 29 2014

...VALID 18Z FRI AUG 29 2014 - 00Z SUN AUG 31 2014...
...REFERENCE AWIPS GRAPHIC UNDER...DAY 1 EXCESSIVE RAINFALL...


SLIGHT RISK OF RAINFALL EXCEEDING FFG TO THE RIGHT OF A LINE FROM
20 ENE SUE 20 SSW SUE OSH 20 N PDC 25 WNW ALO 20 ENE EBS
10 SW AIO 20 SSW OFF 15 S LNK 30 SE JYR 10 SW JYR AUH GRI
25 SE ODX 20 E ODX BVN 25 WNW OFK 20 NW OFK 25 NNE OFK 15 W SUX
15 SE LRJ 15 S SPW MWM 15 ENE JYG 10 E OEO 10 WSW HYR
35 SSW CWCJ 20 NNE CYXZ 20 SSE CYXZ 35 NW ERY 30 NW P75 ESC
20 ENE SUE.


UPPER MS VALLEY INTO THE UPPER LAKES


AN ELONGATED SLIGHT RISK AREA WAS MAINTAINED THIS FORECAST PERIOD
AHEAD OF THE MID TO UPPER LEVEL TROF PUSHING EAST NORTHEASTWARD
OUT OF THE CENTRAL PLAINS INTO THE UPPER MS VALLEY/UPPER LAKES
REGION.  PW VALUES FORECAST TO REMAIN ABOVE AVERAGE---1.5 TO 2+
STANDARD DEVIATIONS ABOVE THE MEAN---AHEAD OF THESE HEIGHT FALLS.
 CONVECTION LIKELY TO REMAIN ACTIVE IN THIS HIGH PW AXIS AS WELL
DEFINED UPPER DIFFLUENCE AHEAD OF THE AFOREMENTIONED HEIGHT FALLS
ENHANCE UVVS ACROSS THESE REGIONS.  OVERALL THERE IS GOOD MODEL
CONSENSUS FOR HEAVY RAINS---ALTHOUGH THERE IS THE USUAL AMOUNT OF
LATITUDINAL DIFFERENCES WITH THE RESPECTIVE MODEL QPF AXES.  THE
IN HOUSE PSEUDO BIAS CORRECTED MEAN USED FOR THE AXIS--WITH
POTENTIAL FOR A PERIOD OF TRAINING OR SLOW MOVEMENT OF CELLS
ACROSS THESE AREAS.  ISOLATED SHORT TERM PRECIPITATION TOTALS OF
1-2"+ MAY RESULT IN ISOLATED RUNOFF ISSUES ACROSS THESE AREAS IN
AREAS OF SLOW MOVEMENT OR TRAINING OF CELLS.


TEXAS GULF COAST

AT LEAST TWO SLOW MOVING LOW TO MID LEVEL CIRCULATION OVER THE
WESTERN GULF OF MEXICO WILL KEEP CONVECTION ACTIVE ACROSS THIS
AREA THIS PERIOD.   THERE SEEMS TO BE GENERAL AGREEMENT THAT ONE
CENTER MAY BE LIFTED NORTHEASTWARD INTO THE LOWER MS VALLEY---ON
THE SOUTHEAST SIDE OF THE UPPER MS VALLEY TROF---WHILE THE
CIRCULATION OFF THE SOUTH TX COAST MOVES LITTLE.  WITH PW VALUES
1.5-2+ STANDARD DEVIATIONS ABOVE THE MEAN OVER THE WESTERN GULF IN
THE VICINITY OF THESE CIRCULATIONS---HEAVY PRECIPITATION POTENTIAL
WILL PERSIST.  THAT SAID---CONFIDENCE STILL IS NOT GREAT WITH QPF
DETAILS WITH BOTH SYSTEMS AS THERE ARE DIFFERENCES IN HOW QUICKLY
ONE VORT IS PICKED UP TO THE NORTHEAST AND DIFFERENCES WITH THE
CONVECTIVE DETAILS NEAR THE SLOW MOVING VORT OFF THE SOUTH TX
COAST---THAT  WILL LIKELY REMAIN POORLY DEPICTED IN THE MODELS.
VERY HEAVY RAINFALL AMOUNTS POSSIBLE WITH BOTH VORTS---WITH
POTENTIAL FOR ISOLATED VERY HEAVY TO EXCESSIVE RAINFALL AMOUNTS.
GIVEN THE HIGH FFG VALUES ACROSS THESE REGIONS---A RISK AREA WAS
NOT DEPICTED.  IN AREAS THAT CONVECTION DOES ENHANCE---VERY HEAVY
RAINFALL TOTALS POSSIBLE WITH ISOLATED 1-2"+ AMOUNTS IN AN HOUR OR
TWO AND ISOLATED TOTALS OF 3-5"+.


ORAVEC
$$





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