Quantitative Precipitation Forecast
Issued by NWS

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FOUS30 KWBC 210652
QPFERD

EXCESSIVE RAINFALL DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
252 AM EDT MON JUL 21 2014

...VALID 06Z MON JUL 21 2014 - 12Z TUE JUL 22 2014...
...REFERENCE AWIPS GRAPHIC UNDER...DAY 1 EXCESSIVE RAINFALL...


SLIGHT RISK OF RAINFALL EXCEEDING FFG TO THE RIGHT OF A LINE FROM
15 N K7L2 15 SSE BIS BIS 20 N BIS 40 N BIS 25 SW K5H4
10 SSW K5H4 15 ESE K5H4 20 N K46D 30 SE DVL 25 WSW RDR
15 SSE GFK 15 ESE CKN 15 NNE FSE 25 N BJI 20 NW FOZ ORB
20 NW ELO 20 NE ELO 30 WNW CKC 15 ESE GNA 40 SE GNA 45 NNE IWD
30 NNE IWD 20 NNE IWD 25 NW IWD 25 SE TWM COQ BRD 15 WSW SAZ
20 ESE FFM 20 WSW FFM 25 E KGWR KGWR 10 WNW K2D5 45 SSW JMS
35 ENE K7L2 20 NE K7L2 15 N K7L2.


SIGNIFICANT CONVECTIVE/MCS DEVELOPMENT EXPECTED THRU THIS REGION
LATER MONDAY AFTERNOON AND NIGHT AS H5 S/WV ENERGY TURNING MORE
EASTWARD OUT OF THE GREAT BASIN/NORTHERN ROCKIES REACHES THE
NORTHERN PLAINS LATER THIS AFTERNOON AND CONTINUES THRU THE UPPER
MS VALLEY MONDAY NIGHT.  SURFACE LOW PRESSURE PULLING OUT OF THE
DAKOTAS INTO MN LATER MONDAY AFTERNOON INTO MONDAY NIGHT ALONG
WITH A COLD FRONT DROPPING SLOWLY SOUTHEASTWARD THRU THE REGION
SHOULD FOCUS THE CONVECTION..WITH AN INCREASING SOUTHWESTERLY LOW
LEVEL JET BRINGING HIGHER MOISTURE INTO THE SYSTEM AND WITH PWS
EVENTUALLY FORECAST TO POOL TO NEAR OR SLIGHTLY ABOVE 2 INCHES
VICINITY OF THE SURFACE BOUNDARY.  IN GENERAL..ALL OF THE MODEL
QPF GUIDANCE IS INDICATING A HEAVY TO VERY HEAVY RAINFALL
EVENT..ALTHOUGH THERE CONTINUE TO BE SOME MOSTLY LATITUDE
DIFFERENCES ON JUST WHERE THE HEAVIEST RAINS WILL OCCUR.  THE
UKMET..CANADIAN AND NAM MODELS WERE CONSIDERED NORTH AND WEST
OUTLIERS WITH THE HEAVIEST RAINFALL AXIS..WHILE THE GFS SEEMS TO
BE SUFFERING FROM FEEDBACK PROBLEMS AND WAS NOT STRONGLY
CONSIDERED.  THE SUITE OF HIRES QPF GUIDANCE..INCLUDING THE
ARW..NMMB AND NSSL WRF WERE THE PREFERRED SOLUTIONS WITH THE
HEAVIER RAINFALL AXIS A LITTLE FARTHER SOUTH AND EAST..WITH THE
OLD ECMWF HIRES ALSO IN THIS CAMP.  VERY HIGH MOISTURE AND INTENSE
RAINFALL RATES WILL SUPPORT SOME ISOLATED 1-2 INCH RAINFALL
AMOUNTS IN A COUPLE OF HOURS..WITH SOME 2-3+ INCH TOTALS THIS
ENTIRE PERIOD LIKELY WITHIN THE THREAT AREA..IN SPITE OF WHAT
SHOULD BE A GENERALLY FORWARD PROPAGATING SYSTEM.  THESE RAINFALL
RATES/AMOUNTS COULD CAUSE SOME ISOLATED FLOODING PROBLEMS WITHIN
THE THREAT AREA.

TERRY





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