000
FOUS30 KWBC 201011
QPFERD

EXCESSIVE RAINFALL DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
610 AM EDT MON MAY 20 2013

...VALID 12Z MON MAY 20 2013 - 12Z TUE MAY 21 2013...
...REFERENCE AWIPS GRAPHIC UNDER...DAY 1 EXCESSIVE RAINFALL...


SLIGHT RISK OF RAINFALL EXCEEDING FFG TO THE RIGHT OF A LINE FROM
30 ENE BIL 55 SW MLS 35 SSW MLS 15 NE MLS 30 SE OLF 40 ENE CYEN
15 SSE CXWN 20 NE CWDV 30 S CYTJ P59 20 NW COQ 30 SSW JKJ
25 NW KBAC 15 NW K46D 35 SW KY19 35 S HEI 20 N CUT 15 W IKA
20 NW DHS 30 WSW PIN 15 NNE GEY 40 S BIL 30 ENE BIL.

SLIGHT RISK OF RAINFALL EXCEEDING FFG TO THE RIGHT OF A LINE FROM
20 W PNT 10 SSW TAZ 30 S UNO 30 SE FSM 10 E ADM 20 NNE DUC
15 NW PWA 15 NW PPF 25 WSW EOK 30 NW C75 20 W PNT.


...NORTHERN PLAINS INTO THE UPPER MISSISSIPPI VALLEY...

STILL SEE A THREAT FOR SOME FLOODING PROBLEMS OVER PORTIONS OF THE
NORTHERN PLAINS (INCLUDING THE HIGH PLAINS OF MT/WY) INTO NORTHERN
MINNESOTA...ESPECIALLY WHERE FLASH FLOOD GUIDANCE VALUES ARE QUITE
LOW IN ND AND SOUTH-CENTRAL MT (MOST NOTABLY OVER THE BURN SCAR
AREAS IN MT).  MOIST INFLOW WILL CONTINUE TO FUEL
DEFORMATION/DYNAMIC COOLING RAINS ON THE BACKSIDE OF THE FAIRLY
INTENSE AND SLOW MOVING CLOSED H5 LOW OVER THE NORTHERN HI PLAINS
AT THIS TIME.  THE REALLY HIGH PW`S WILL LIKELY REMAIN WELL TO THE
SOUTH AND EAST WITH THE EXPECTED CONVECTIVE DEVELOPMENT OVER THE
MIDWEST AND UPPER MS VALLEY....BUT LONG DURATION OF THE EVENT
COULD POSE THE BIGGER CONCERN.  EXPECT SOME 0.50-1.00 INCH
RAINFALL AMOUNTS IN A 3-6 HOUR PERIOD..BUT WITH SOME 1-2 INCH
TOTALS POSSIBLE THIS ENTIRE PERIOD.


...SOUTHERN PLAINS INTO THE LOWER AND MID MISSISSIPPI VALLEY...

THE EXCESSIVE RAINFALL RISK AREA (SLIGHT) SHIFTED A LITTLE FARTHER
TO THE EAST FROM THE PREVIOUS FCST PACKAGE.  MULTI-CELLULAR
CONVECTION OVERNIGHT SUN INTO EARLY MON WILL CONTINUE TO MOISTEN
THE SOILS SOMEWHAT OVER A FAIRLY LARGE SWATH AND LIKELY LEAD TO
LOWERING FFG LATER MON INTO MON NIGHT. BOTH THE GLOBAL AND HIGH
RES MODELS CLUSTER FAIRLY WELL WITH RESPECT TO THE ADVERTISEMENT
OF ANOTHER MCS MON NIGHT INTO EARLY TUE...WITH THE HIGHEST
AREAL-AVG DETERMINISTIC QPF AND ENSEMBLE PROBABILITIES OF AMOUNTS
EXCEEDING 3-5 INCHES ACROSS SE KANSAS...ERN OKLAHOMA...SW AND CEN
MISSOURI...AND NW ARKANSAS.  OVER THIS REGION...A VEERING (S-SW)
40-50 KT LLJ IS EXPECTED TO DEVELOP OVERNIGHT...AND IS EXPECTED TO
FEED OFF OF A MOISTURE-RICH AIRMASS (PW`S ~1.75" AND K INDICES IN
THE MID TO UPPER 30S) TO GENERATE A FAIRLY ROBUST AREA OF LLVL
MOISTURE TRANSPORT AND FLUX CONVERGENCE.  DYNAMICALLY...THE BROAD
AREA OF UPPER LEVEL AGEOS DIVERGENCE/DEEP LAYER QS CONVERGENCE
OVER THIS REGION WILL GET ENHANCED BY THE LEFT EXIT/RIGHT ENTRANCE
REGION OF THE SRN JET STREAK EMERGING OUT OF THE TROUGH BASE AND
THE NRN JET STREAK ACROSS THE UPPER MIDWEST RESPECTIVELY.
MEANWHILE...THE STRENGTHENING (AND VEERING) LLJ JET WILL LEAD TO
AN INCREASED SOUTHERLY PROPAGATION OVERNIGHT AND PSBL TRAINING
CELLS GIVEN A SLOWER...MORE SOUTHWESTWARD ORIENTED CORFIDI OR MBE
VECTOR.

HURLEY
$$