SPC AC 240545
DAY 2 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
1245 AM CDT FRI JUL 24 2009
VALID 251200Z - 261200Z
...THERE IS A SLGT RISK OF SVR TSTMS ACROSS PARTS OF THE OH
VALLEY...
...OH VALLEY/MID-MS VALLEY/OZARKS ...
AN UPPER-LEVEL LOW IS FORECAST TO MOVE SEWD INTO THE GREAT LAKES
REGION SATURDAY. SOME THUNDERSTORM ACTIVITY SHOULD BE ONGOING
SATURDAY MORNING ASSOCIATED WITH A WELL-DEVELOPED LOW-LEVEL JET. SFC
HEATING...LOW-LEVEL CONVERGENCE AND STRONG LARGE-SCALE ASCENT
SOUTHEAST OF THE UPPER-LEVEL LOW SHOULD RESULT IN SCATTERED TO
NUMEROUS THUNDERSTORM DEVELOPMENT AROUND MIDDAY AHEAD A FAST-MOVING
COLD FRONT FROM OHIO SWWD ACROSS THE OH VALLEY. THE ACTIVITY IS
FORECAST TO DEVELOP IN THE EXIT REGION OF A WELL-DEFINED MID-LEVEL
JET WHICH SHOULD CREATE 35 TO 45 KT OF VERTICAL SHEAR EVIDENT ON
FORECAST SOUNDINGS. THIS COMBINED WITH MODERATE INSTABILITY AND 40
KT OF FLOW AT 850 MB SHOULD BE FAVORABLE FOR ISOLATED WIND DAMAGE.
COLD AIR ALOFT AND THE VERTICAL SHEAR MAY ALSO BE ENOUGH FOR HAIL
WITH THE STRONGER UPDRAFTS. ALTHOUGH LOW-LEVEL FLOW AND VERTICAL
SHEAR WEAKEN WSWWD ACROSS THE MID-MS VALLEY INTO THE OZARKS...ENOUGH
INSTABILITY IS FORECAST SATURDAY AFTERNOON FOR STRONG UPDRAFTS WITH
A MARGINAL SEVERE THREAT MAINLY NEAR PEAK HEATING.
...ECNTRL CO/SE WY...
AN UPPER-LEVEL RIDGE IS FORECAST TO BE IN PLACE ACROSS THE SRN
ROCKIES SATURDAY. NORTH OF THE RIDGE...SCATTERED THUNDERSTORMS
SHOULD DEVELOP IN THE HIGHER TERRAIN OF ECNTRL CO AND SE WY BY EARLY
AFTERNOON. FORECAST SOUNDINGS ALONG THIS CORRIDOR SATURDAY AFTERNOON
SHOW MODERATE VERTICAL SHEAR PROFILES MAINLY FROM SPEED SHEAR ABOVE
500 MB. THIS ALONG WITH STEEP MID-LEVEL LAPSE RATES MAY BE ENOUGH
FOR MARGINALLY SEVERE HAILSTORMS DURING THE LATE AFTERNOON.
...WRN MT...
AN UPPER-LEVEL LOW IS FORECAST TO MOVE NEWD ACROSS THE PACIFIC
NORTHWEST SATURDAY. AHEAD OF THE UPPER-LEVEL LOW...AN AXIS OF
INSTABILITY IS FORECAST TO BE LOCATED FROM NW WY EXTENDING NWWD
ACROSS WRN MT. VERTICAL SHEAR IS FORECAST TO INCREASE ACROSS THE
REGION AS THE UPPER-LEVEL LOW MOVES EWD. THIS COMBINED WITH STEEP
LAPSE RATES MAY BE ENOUGH FOR MARGINALLY SEVERE STORMS CAPABLE OF
STRONG WIND GUSTS AND HAIL.
..BROYLES.. 07/24/2009
CLICK TO GET WUUS02 PTSDY2 PRODUCT
NOTE: THE NEXT DAY 2 OUTLOOK IS SCHEDULED BY 1730Z
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