Mesoscale Discussion 1887

Issued

Sep 5, 2012, 1:14 AM CDT (06:14 UTC)

Expired

Sep 5, 2012, 2:45 AM CDT

In force

91 min

Issued by

the Storm Prediction Center

The La Crosse radar (KARX), 154 km from the middle of the area, began a volume at 06:14 UTC, the scan nearest the moment this went out.

Open the radar archive at this moment

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428 
ACUS11 KWNS 050615
SWOMCD
SPC MCD 050614
WIZ000-ILZ000-IAZ000-MNZ000-050745-

MESOSCALE DISCUSSION 1887
NWS STORM PREDICTION CENTER NORMAN OK
0114 AM CDT WED SEP 05 2012

AREAS AFFECTED...SERN MN...SRN WI...NRN IA

CONCERNING...SEVERE THUNDERSTORM WATCH 617...618...

VALID 050614Z - 050745Z

THE SEVERE WEATHER THREAT FOR SEVERE THUNDERSTORM WATCH
617...618...CONTINUES.

SUMMARY...RISK FOR DAMAGING WIND GUSTS CONTINUES...BUT MAY BEGIN TO
DIMINISH WITH THE LEAD STORM CLUSTER NOW SPREADING ACROSS THE UPPER
MISSISSIPPI VALLEY INTO SOUTHERN WISCONSIN WITHIN THE NEXT COUPLE OF
HOURS.

DISCUSSION...INTENSE CONVECTION CONTINUES ALONG THE LEADING EDGE OF
THE SIGNIFICANT EASTWARD PROPAGATING SURFACE COLD POOL...AND WITHIN
A ZONE OF LOW-LEVEL WARM ADVECTION DOWNSTREAM...ALONG THE STALLED
WESTERN FLANK OF THE COLD POOL ASSOCIATED WITH THE DISSIPATING STORM
CLUSTER NOW SOUTH OF LAKE MICHIGAN.  THROUGH 07-08Z...AIDED BY
FORCING ASSOCIATED WITH A SUPPORTING MID-LEVEL JET STREAK...ACTIVITY
APPEARS LIKELY TO CONTINUE EASTWARD ACROSS THE UPPER MISSISSIPPI
VALLEY INTO SOUTHERN WISCONSIN...WHERE THE LOW-LEVEL ENVIRONMENT HAS
BEEN COOLED AND STABILIZED BY PRIOR CONVECTION.  AS THIS OCCURS...
DAMAGING WIND POTENTIAL SEEMS MORE LIMITED...AND THREAT SHOULD
DIMINISH FURTHER AS INFLOW OF MORE STABLE AIR WEAKENS CONVECTION.

MODELS DO INDICATE THAT A MODERATE LOW-LEVEL JET WILL PERSIST TO THE
WEST OF THIS ACTIVITY THROUGH THE NIGHT...WHERE INFLOW AND LIFT OF
MOIST AND MODERATELY UNSTABLE AIR MAY MAINTAIN VIGOROUS CONVECTIVE
DEVELOPMENT ABOVE THE TRAILING SURFACE COLD POOL... ACROSS PARTS OF
NORTH CENTRAL INTO EASTERN IOWA.  HEAVY RAINFALL ...FREQUENT
LIGHTNING AND LOCALLY STRONG SURFACE GUSTS MAY NOT BE OUT OF THE
QUESTION WITH THIS ACTIVITY.

..KERR.. 09/05/2012

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

ATTN...WFO...GRB...LOT...MKX...DVN...ARX...MPX...DMX...FSD...
OAX...

LAT...LON   44259191 44278994 43628920 42668883 41318995 41209118
            41309300 41489480 41769574 42439574 43069467 43949382
            44259191

Mesoscale Discussions in Iowa, 2012Mesoscale Discussions in Wisconsin, 2012Mesoscale Discussions in Minnesota, 2012Every mesoscale discussion in 2012

The product and its follow-ups from the Iowa Environmental Mesonet's archive of National Weather Service and Storm Prediction Center text; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.