[MCD] SWOMCD

[Mesoscale Convective Discussions]

ACUS11 KWNS 311813
SWOMCD
SPC MCD 311812 
MNZ000-SDZ000-NDZ000-312015-

MESOSCALE DISCUSSION 1684
NWS STORM PREDICTION CENTER NORMAN OK
0112 PM CDT MON JUL 31 2006

AREAS AFFECTED...PARTS OF CNTRL/ERN DAKOTAS INTO NRN MN

CONCERNING...SEVERE THUNDERSTORM POTENTIAL...HEAVY RAINFALL 

VALID 311812Z - 312015Z

HEAVY RAIN IS EXPECTED TO BECOME AN INCREASING THREAT WITH
DEVELOPING LINE OF STORMS THIS AFTERNOON.  POTENTIAL FOR INCREASING
SEVERE POTENTIAL WILL BE MONITORED.

PROGRESSIVE UPSTREAM SHORT WAVE TROUGHS ARE CONTRIBUTING TO THE
DEVELOPMENT AND EASTWARD PROGRESSION OF A ZONE OF LARGE-SCALE ASCENT
ACROSS THE NORTHERN PLAINS.  THIS CURRENTLY APPEARS TO BE
CONCENTRATED IN A POST FRONTAL BAND FROM NORTH CENTRAL SOUTH DAKOTA
INTO NORTH CENTRAL MINNESOTA...WHERE INCREASE IN CONVECTIVE
DEVELOPMENT IS ONGOING.  THOUGH LOW-LEVEL POST FRONTAL ENVIRONMENT
IS SUBSTANTIALLY COOLER...AIR MASS IS VERY MOIST WITH INFLUX OF
SUBTROPICAL MID-LEVEL MOISTURE CONTRIBUTING TO PRECIPITABLE WATER
CONTENT IN EXCESS OF 2 INCHES. MOST UNSTABLE CAPE OF 1500-3000 J/KG
WILL BE SUPPORTIVE OF VIGOROUS UPDRAFTS CAPABLE OF PRODUCING LOCALLY
VERY HEAVY RAIN...WHICH COULD BECOME EXCESSIVE LATER THIS AFTERNOON
AS SLOW MOVING LINE OF STORMS GRADUALLY EVOLVES.  THIS COULD IMPACT
AREAS FROM BEMIDJI/THIEF RIVER FALLS SOUTHWARD THROUGH
FARGO/ABERDEEN...PERHAPS CHAMBERLAIN SD BY 21-22Z.

DAMAGING WIND POTENTIAL IS UNCERTAIN...BUT PRECIPITATION LOADING AND
LOWER LEVEL EVAPORATIVE COOLING MAY BECOME SUFFICIENT TO SUPPORT
POTENTIAL FOR GUSTY WINDS NEAR STRONG CELLS.  AS ACTIVITY
CONSOLIDATES...GUST FRONT ON LEADING EDGE OF OUTFLOW COULD
STRENGTHEN AS IT ADVANCES TOWARD MORE STRONGLY HEATED BOUNDARY LAYER
ACROSS EASTERN SOUTH DAKOTA/WESTERN MINNESOTA.

..KERR.. 07/31/2006

...PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT...

ATTN...WFO...DLH...FGF...FSD...ABR...BIS...

44689920 45819863 47549695 48489489 47989322 47229390
46889452 46049650 45539695 45159738 44269845 43609945
44179934 

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