Severe Storm Outlook Narrative (AC)
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000
ACUS11 KWNS 211405
SWOMCD
SPC MCD 211404
WIZ000-ILZ000-IAZ000-MNZ000-211530-

MESOSCALE DISCUSSION 1593
NWS STORM PREDICTION CENTER NORMAN OK
0904 AM CDT THU AUG 21 2014

AREAS AFFECTED...PARTS OF SERN MN/WI...NRN IL AND NRN IA

CONCERNING...SEVERE THUNDERSTORM WATCH 471...

VALID 211404Z - 211530Z

THE SEVERE WEATHER THREAT FOR SEVERE THUNDERSTORM WATCH 471
CONTINUES.

SUMMARY...THE SEVERE WIND/HAIL THREAT APPEARS TO BE DIMINISHING.
SUBSTANTIVE NEW DEVELOPMENT OR RE-INTENSIFICATION CURRENTLY APPEARS
UNLIKELY THROUGH AT LEAST EARLY AFTERNOON...AND THE REMAINING VALID
PORTION OF WW 471 MAY BE CANCELLED PRIOR TO THE 17Z SCHEDULED
EXPIRATION.

DISCUSSION...ALTHOUGH THE NOCTURNAL SOUTHERLY LOW-LEVEL JET
CONTINUES TO WEAKEN...LARGE-SCALE FORCING REMAINS SUFFICIENT TO
MAINTAIN CONVECTIVE DEVELOPMENT ACROSS THE REGION.  ONE MID-LEVEL
SHORT WAVE IMPULSE AND ASSOCIATED CONVECTIVELY GENERATED OR ENHANCED
CYCLONIC CIRCULATION ARE EXPECTED TO CONTINUE SHIFTING EAST OF THE
UPPER MISSISSIPPI VALLEY INTO THE UPPER GREAT LAKES REGION THROUGH
MID DAY...IN THE PRESENCE OF OTHERWISE GENERALLY RISING MID-LEVEL
HEIGHTS.  A TRAILING MID-LEVEL CYCLONIC VORTICITY CENTER APPEARS
LIKELY TO CONTINUE SHIFTING EAST NORTHEAST OF THE MID MISSOURI
VALLEY...AND COULD CONTRIBUTE TO THE MAINTENANCE OF CONVECTIVE
DEVELOPMENT ALONG AN EFFECTIVE WARM FRONTAL ZONE NEAR OR JUST SOUTH
OF THE MINNESOTA BORDER.  HOWEVER...ONGOING THUNDERSTORM ACTIVITY
APPEARS GENERALLY ROOTED WITH FORCING ABOVE THE BOUNDARY
LAYER...WITH LITTLE EVIDENCE OF A SIGNIFICANT SURFACE COLD
POOL...AND THIS SEEMS LIKELY TO REMAIN THE CASE THROUGH AT LEAST
EARLY AFTERNOON.

..KERR.. 08/21/2014

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

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

LAT...LON   45558979 43998771 42738785 41668919 41629103 41759255
            41949386 42519446 43719377 43909181 44139031 45449170
            45558979




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