[MCD] SWOMCD

Mon Jul 17 17:11:13 UTC 2006

ACUS11 KWNS 171710
SWOMCD
SPC MCD 171709 
MIZ000-WIZ000-ILZ000-IAZ000-MNZ000-171915-

MESOSCALE DISCUSSION 1536
NWS STORM PREDICTION CENTER NORMAN OK
1209 PM CDT MON JUL 17 2006

AREAS AFFECTED...NERN IA...SERN MN...EXTREME NRN IL...CNTRL AND SRN
WI THROUGH ERN UPPER MI AND NRN LOWER MI

CONCERNING...SEVERE THUNDERSTORM POTENTIAL 

VALID 171709Z - 171915Z

SURFACE BASED THUNDERSTORMS ARE EXPECTED TO DEVELOP BY 20Z OVER WRN
PARTS OF THE UPPER GREAT LAKES AREA. SUPERCELLS AND BOW ECHOES WITH
VERY LARGE HAIL AND DAMAGING WIND WILL BE THE PRIMARY THREATS. ONE
OR MORE WWS MAY BE NEEDED BY 19Z.

A COLD FRONT EXTENDS FROM THE CNTRL UPPER PENINSULA OF MI SWWD
THROUGH N CNTRL WI...SERN MN AND INTO NRN IA. THIS BOUNDARY WILL
MOVE SEWD TODAY AS AN UPPER TROUGH ADVANCES EWD THROUGH SRN CANADA
AND THE GREAT LAKES. OTHER BOUNDARIES ASSOCIATED WITH OUTFLOW FROM
ONGOING ELEVATED STORMS EXTEND FROM NERN IA INTO SRN WI. A STRONG
ELEVATED MIXED LAYER HAS ADVECTED EWD OVER RICH LOW LEVEL MOISTURE
RESULTING IN STRONG INSTABILITY IN THE PRE-FRONTAL WARM SECTOR. AS
TEMPERATURES CLIMB INTO THE UPPER 80S AND LOWER 90S...MLCAPE WILL
APPROACH 4000 J/KG. THE SWLY LOW LEVEL JET WILL SHIFT ENEWD AWAY
FROM THE WARM SECTOR IN ASSOCIATION WITH A STRONGER SHORTWAVE TROUGH
OVER SRN ONTARIO. THE WEAKENING LOW LEVEL FLOW WILL RESULT IN WEAKER
FRONTAL CONVERGENCE...AND MAY DELAY SURFACE BASED INITIATION ANOTHER
FEW HOURS UNTIL BOUNDARY LAYER HEATING AND MIXING FURTHER WEAKENS
THE CAP. UNIDIRECTIONAL WSWLY WIND PROFILES WITH 30-40 KT MID LEVEL
FLOW WILL PERSIST ALONG SRN PERIPHERY OF UPPER TROUGH IN VICINITY OF
THE FRONT. THIS WILL SUPPORT 0-6 KM SHEAR OF 30 TO 35
KT...SUFFICIENT FOR SUPERCELL STORM STRUCTURES ESPECIALLY GIVEN THE
STRONG MAGNITUDE OF INSTABILITY. SOME STORMS MAY ALSO EVOLVE INTO
BOWING SEGMENTS.

..DIAL.. 07/17/2006

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

ATTN...WFO...APX...GRR...MQT...GRB...MKX...DVN...ARX...MPX...DMX...

43309372 43909266 44459122 45218994 45898797 46528713
46608493 46098406 45238381 44388603 42628846 42199256 

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