MESOSCALE PRECIPITATION DISCUSSION 0407
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
902 PM EDT WED JUN 28 2017

AREAS AFFECTED......NORTHERN MO...

CONCERNING...HEAVY RAINFALL

VALID 290100Z - 290600Z

SUMMARY...A CLUSTER OF SHOWERS AND THUNDERSTORMS ACROSS SOUTHERN
IA AND NORTHERN MO ARE EXPECTED TO PERSIST THROUGH THIS EVENING. 2
TO 4 INCHES OF RAIN IS EXPECTED WITH ISOLATED HIGHER TOTALS
LIKELY.

DISCUSSION...A BAND OF SHOWERS/STORMS HAVE FORMED NEAR THE NOSE OF
AN 850 MB LOW LEVEL JET OF 40-50 KT.  THE ACTIVITY IS EXPECTED TO
CONTINUE MOVING EAST ACROSS SOUTHERN IA AND NORTHERN MO IN TANDEM
WITH THE LOW LEVEL JET AND POOL OF HIGHER SURFACE DEWPOINTS IN THE
UPPER 60S TO LOWER 70S F.  THE 23Z RAP INITIALIZED AVAILABLE
PRECIPITABLE WATER NEAR 1.8-1.9 INCHES AND FORECASTS OCCASIONAL
MAXIMA TO 2 INCHES.

THE HIGH AVAILABLE MOISTURE...CONTINUING INFLOW...AND MIXED LAYER
CAPES IN NORTHERN MO TO 3000 J/KG FAVOR REDEVELOPMENT OF
SHOWERS/STORM ALONG THE OUTFLOW BOUNDARY.

PRECIPITABLE WATER VALUES ARE 1.75-2.0" IN THE 23Z RAP ANALYSIS.

EXPECTATIONS ARE FOR THE CONVECTION TO CONTINUE PROPAGATING
STEADILY EAST NEAR 20 KT WITH OCCASIONAL TRAINING OF BANDS
PROVIDING REPEAT ACTIVITY.  AREAS OF PROLONGED HEAVIER RAIN RATES
WILL LEAD TO LOCALIZED FLOODING OF LOW LYING AND POORLY DRAINED
AREAS. 

THE 20-22Z HIGH RES RAPID REFRESH RUNS HAVE BEEN INDICATING 2 TO 4
INCHES OF RAIN...AS WELL AS THE 12Z HIGH RES WRF NMMB. 
HOURLY RAIN RATES TO 2" AND LOCAL AMOUNTS TO 4" ARE POSSIBLE IN
SOUTHERN IA AND NORTHERN MO.

PETERSEN

ATTN...WFO...DMX...DVN...EAX...LSX...OAX...

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

LAT...LON   40729313 40389191 39779183 39739308 39809447
            40159517 40609494