Monday, July 28, 2008

Slight risk of severe storms on Tuesday


Techincal forecast discussion from the Storm Prediction Center. Looks like I will be tracking storms (when not cleaning around here). :-) -ERIC
  ...UPPER MS VALLEY INTO THE WRN GREAT LAKES...
NOCTURNAL STRONG/SEVERE STORMS MOVING EWD/SEWD OVER THE NRN PLAINS
MAY PERSIST INTO PARTS OF WRN IA/SRN MN AREA AT THE START OF THE
PERIOD. THESE STORMS MAY WEAKEN DURING THE MORNING AS THE NOCTURNAL
LOW LEVEL JET VEERS AND WEAKENS. HOWEVER...THE AIR MASS AHEAD OF
THIS ACTIVITY IS EXPECTED TO UNDERGO SUBSTANTIAL DESTABILIZATION
DURING THE DAY AS DEW POINTS INCREASE IN THE WARM SECTOR AND
ELEVATED MIXED LAYER AND ATTENDANT STEEP MID LEVEL LAPSE RATES
SPREADS EWD FROM SRN MN AND IA INTO NRN IL/WI/LOWER MI. THIS WILL
RESULT IN MLCAPE VALUES OF 2000-3000 J/KG DURING THE AFTERNOON AND
EVENING ACROSS PARTS OF SERN MN/ERN IA INTO WI AND NRN IL.

THUNDERSTORMS ARE EXPECTED TO INCREASE DURING THE AFTERNOON
ALONG/AHEAD OF THE COLD FRONT MOVING ACROSS THE UPPER MS VALLEY IN
RESPONSE TO DYNAMIC FORCING IN ADVANCE OF THE SHORT WAVE TROUGH. IN
ADDITION...IF MORNING STORMS CAN PERSIST INTO THE EARLY AFTERNOON
THE LIKELIHOOD OF INTENSIFICATION IS LIKELY AS THEY MOVE INTO AN
INCREASINGLY UNSTABLE ENVIRONMENT. WINDS ALOFT AND RESULTANT
VERTICAL SHEAR /35-45 KT IN THE LOWEST 6 KM/ WILL BE MOST FAVORABLE
ACROSS THE NRN PARTS OF THE OUTLOOK AREA...HOWEVER SHEAR IS EXPECTED
TO BE SUFFICIENTLY STRONG TO ENHANCE STORM ORGANIZATION AS FAR SOUTH
AS SERN IA AND NRN IL. STRONGER STORMS WILL HAVE POTENTIAL TO
PRODUCE LARGE HAIL AND DAMAGING WINDS AS THEY MOVE EWD/ESEWD THROUGH
THE EVENING HOURS.

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