MESOSCALE PRECIPITATION DISCUSSION 0481
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
947 PM EDT SUN SEP 06 2015
 
AREAS AFFECTED...SOUTHEAST MN...WI 
 
CONCERNING...HEAVY RAINFALL...FLASH FLOODING LIKELY 
 
VALID 070145Z - 070645Z
 
SUMMARY...INCREASING THREAT FOR TRAINING CONVECTION OVER THE NEXT
FEW HOURS AS CELL REGENERATION OCCURS. ANOMALOUS MOISTURE OVER THE
REGION WILL FAVOR INTENSE RAINFALL RATES. FLASH FLOODING IS
EXPECTED LOCALLY.

DISCUSSION...CELL-REGENERATION IS OCCURRING IN EARNEST OVER
PORTIONS OF SOUTHEAST MN AND ESPECIALLY INTO WESTERN WI AS AN
APPROACHING COLD FRONT INTERACTS WITH A VERY MOIST AND MODERATELY
UNSTABLE AIRMASS. THE CONVECTION ACROSS THIS REGION IS
REGENERATING WITH A FAIRLY DIFFLUENT FLOW REGIME ALOFT WHICH IS
BEING AIDED BY THE EJECTION OF HEIGHT FALLS/TROUGHING ACROSS THE
NORTHERN PLAINS AND TOWARD THE UPPER MS VALLEY.

IN COORDINATION WITH NESDIS/SAB...THE INSTABILITY TRENDS HAVE
STEADILY RECOVERED THIS EVENING IN THE WAKE OF EARLIER
CONVECTION...AND GIVEN THE LATEST CONVECTIVE TRENDS...THERE WILL
BE THE POTENTIAL FOR HEAVY RAINS FALLING OVER AREAS THAT HAVE SEEN
LOCALLY A COUPLE OF INCHES OF RAIN EARLY IN THE DAY.

IN FACT...THE 23Z AND 00Z HRRR RUNS SUGGEST A LIKELIHOOD OF W/E
CELL-TRAINING OVER THE NEXT SEVERAL HOURS...WITH THE POTENTIAL FOR
ADDITIONAL RAINFALL AMOUNTS LOCALLY EXCEEDING 5 INCHES THROUGH
06Z. THIS IS BELIEVABLE CONSIDERING PWATS AS PER LATEST
GPS-DERIVED THAT ARE BETWEEN 2.0 AND 2.2 INCHES. THIS IS HIGHLY
ANOMALOUS FOR EARLY SEPTEMBER...AND GIVEN THE INTENSE DEEPER
CONVECTIVE CORES THAT HAVE ALREADY REGENERATED...RAINFALL RATES
WILL BE VERY HIGH AND MAY EXCEED 2.5 INCHES/HR. FLASH FLOODING IS
LIKELY AT LEAST LOCALLY...AND ESPECIALLY ACROSS PORTIONS OF
WESTERN AND CENTRAL WI WHERE CONVECTION IS ALREADY BEGINNING TO
TRAIN AND ALSO WHERE EARLIER RAINS OCCURRED.

PLEASE CONSULT THE LATEST NESDIS/SAB SPENES MESSAGE FOR ADDITIONAL
INFORMATION.

ORRISON

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

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

LAT...LON   46549058 46278944 45938855 45398794 44788775 
            44268783 43688854 42939003 42229117 42929119 
            43469169 43569237 43539278 43349354 43729309 
            44039289 44569243 45099224 45879223 46389160