Flash Flood Guidance
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000
AWUS01 KWNH 312030
FFGMPD
WIZ000-MNZ000-IAZ000-010200-

MESOSCALE PRECIPITATION DISCUSSION 0277
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
429 PM EDT TUE MAY 31 2016

AREAS AFFECTED...SE MINNESOTA...N WISCONSIN...NE IOWA

CONCERNING...HEAVY RAINFALL...FLASH FLOODING POSSIBLE

VALID 312030Z - 010200Z

SUMMARY...INCREASING CONVECTIVE COVERAGE AND INTENSITY WITH
FAVORABLE FLOW FOR SHORT TERM TRAINING  MAY LEAD TO ISOLATED FLASH
FLOOD CONDITIONS.

DISCUSSION...MST IS POOLING ALONG BOTH FRONTAL BOUNDARIES THAT
MERGE NEAR EAU CLAIRE WI.  COLD FRONT CONVECTION HAS BEEN CYCLING
FOR SOME TIME BEING DRIVEN BY WEAK WESTERLY FLOW/SFC CONVERGENCE
INTERSECTING NEARLY UNIDIRECTIONAL SSWLY FLOW AHEAD OF THE
FRONT...WITH DEEP MST WITH TPW VALUES IN THE 1.3-1.4" RANGE AND
MLCAPE TO 1000 J/KG.  NOW THAT THE FRONT HAS PROGRESSED INTO SE
MN/WI THE LOW LEVEL INFLOW HAS BACKED TOWARD THE SE UNDER THE
INFLUENCE OF RETURN FLOW ALONG THE MERGING FRONTAL ZONE AS WELL AS
A OUTFLOW BOUNDARY FROM CONVECTION ACROSS CENT WI/N CENT IL.  AS
SUCH DEEPER MST FLUX WILL SUPPORT INCREASING UPDRAFT STRENGTH AND
RAINFALL EFFICIENCY.  IR TOPS HAVE COOLED TO BELOW -60C IN
RESPONSE TO THIS...ALLOWING RAIN RATES TO INCREASE TO 1.5-2"/HR
ALONG THE COLD FRONT.  MEAN CELL MOTIONS ARE GENERALLY ALONG THE
FRONT WITH APPROXIMATELY 5 KT OR LESS U-COMPONENT TO THE
PROPAGATION VECTORS...FURTHER REDUCING NORTHWARD INTO THE
CONVECTIVE LINE AND MORE ELEVATED CONVECTION IN THE TROWAL NORTH
OF THE TRIPLE POINT.

HI-RES CAMS HAVE BEEN CONSISTENT WITH PLACEMENT OF RAINFALL MAXIMA
OF 2-3" OVER THE NEXT 6HR MAINLY ACROSS NW WI...HOWEVER WITH
TRAINING ISOLATED HIGHER TOTALS ARE POSSIBLE THAT MAY LEAD TO
LOCALIZED FLASH FLOODING CONDITIONS.

GALLINA

...PLEASE SEE WWW.WPC.NCEP.NOAA.GOV FOR GRAPHIC PRODUCT...

ATTN...WFO...ARX...DLH...DMX...DVN...GRB...MKX...MPX...

ATTN...RFC...NCRFC...

LAT...LON   46419143 46189009 44778978 43248985 42769053
            42559232 43249286 44729216


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