MESO: Mesoscale Discussion 1720

ACUS11 KWNS 190342
SWOMCD
SPC MCD 190341
MIZ000-WIZ000-MNZ000-190545-

MESOSCALE DISCUSSION 1720
NWS STORM PREDICTION CENTER NORMAN OK
1041 PM CDT WED AUG 18 2010

AREAS AFFECTED...WI MI

CONCERNING...SEVERE POTENTIAL...WATCH UNLIKELY

VALID 190341Z - 190545Z

TSTMS MAY BECOME MORE NUMEROUS ACROSS PORTIONS OF NRN WI AND
ADJACENT AREAS OF THE UPPER PENINSULA OF MI OVER THE NEXT FEW HOURS
WITH SOME STORMS POSSIBLY CONTAINING HAIL AND STRONG WINDS. THE AREA
OF CONCERN WILL CONTINUE TO BE MONITORED BUT LATEST INDICATIONS
SUGGEST THAT SEVERE WEATHER POTENTIAL AND STORM COVERAGE WILL NOT
REQUIRE A WATCH.

WITH THE ONSET OF NIGHTTIME AND THE GRADUAL STRENGTHENING OF THE LOW
LEVEL JET...LIFT ACROSS THE QUASI-STATIONARY FRONT SITUATED ACROSS
NCNTRL WI WAS INCREASING. DEEPER ASCENT AND CONTINUED
DESTABILIZATION ABOVE THE STABLE BOUNDARY LAYER WILL LIKELY BE
ENHANCED BY A SUBTLE AND LOW AMPLITUDE MID LEVEL DISTURBANCE
SPREADING SEWD ACROSS MN ATTM. AIR PARCEL TRAJECTORIES BEING LIFTED
ACROSS THE FRONT ORIGINATE WITHIN VERY MOIST/UNSTABLE AND CAPPED
WARM SECTOR AIRMASS SAMPLED BY EARLIER SOUNDINGS AT MPX AND ABR.
GIVEN STEEP MID LEVEL LAPSE RATES AND STRONG EFFECTIVE SHEAR ON THE
ORDER OF 50KT...STORMS WILL HAVE SOME TENDENCY TO PERSIST AND
POSSIBLY GROW UPSCALE ALONG AND NORTH OF THE FRONT OVER THE NEXT FEW
HOURS.

THIS SCENARIO IS SUPPORTED BY LATEST SHORT-TERM NUMERICAL GUIDANCE
INCLUDING THE WRF-HRRR AND LATEST WRF-NMM. ALTHOUGH...THESE MODELS
ALSO SUGGEST THAT STORMS WILL LIKELY REMAIN SOMEWHAT DECOUPLED FROM
THE MORE UNSTABLE BOUNDARY LAYER TO THE SOUTH AND WILL MOVE QUICKLY
AWAY FROM THIS SOURCE REGION OF GREATER INSTABILITY THROUGH THE
NIGHT. THUS...WHILE SOME HAIL/WIND POTENTIAL MAY DEVELOP AND STORMS
SHOULD INCREASE IN COVERAGE FROM WI ACROSS THE U.P. OF MI...THE
OVERALL SEVERE WEATHER POTENTIAL FROM THIS ACTIVITY WILL LIKELY
REMAIN QUITE ISOLATED.

..CARBIN.. 08/19/2010

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

ATTN...WFO...MQT...GRB...DLH...ARX...MPX...

LAT...LON 46318679 45528722 45088790 45308988 45559138 45619231
46109251 46539225 46729149 46919066 46978901 46708749
46318679

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