Thursday, August 30, 2007

DAY2SVR: Nws Storm Prediction Center Norman Ok

ACUS02 KWNS 300533
SWODY2
SPC AC 300532

DAY 2 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
1232 AM CDT THU AUG 30 2007

VALID 311200Z - 011200Z

..NO SVR TSTM AREAS FORECAST...

..SYNOPSIS...
A STRONG SUBTROPICAL HIGH CENTER IS EXPECTED TO PERSIST ACROSS THE
SOUTHERN GREAT BASIN/SOUTHERN PLATEAU REGION THROUGH THIS FORECAST
PERIOD. HOWEVER...MODELS INDICATE THAT THE UPPER RIDGE AXIS NOW
BUILDING TO THE NORTH OF THE HIGH...INTO THE LEE OF THE CANADIAN
ROCKIES...WILL BEGIN TO FLATTEN AND SHIFT EASTWARD THROUGH THE
CANADIAN PRAIRIES ON FRIDAY. THIS IS FORECAST TO OCCUR AS THE FIRST
IN A SERIES OF SHORT WAVE IMPULSES...EMANATING FROM A BROAD
NORTHEASTERN PACIFIC TROUGH...PROGRESSES INLAND ACROSS BRITISH
COLUMBIA/PACIFIC NORTHWEST COASTAL AREAS. DOWNSTREAM...A POLAR
TROUGH APPEARS LIKELY TO CONTINUE EASTWARD ACROSS THE NORTHEAST
STATES/NORTH ATLANTIC COAST REGION. AND...AS THIS OCCURS...A
LOWER/MID TROPOSPHERIC CIRCULATION...WITHIN WEAK TROUGHING BETWEEN
SUBTROPICAL RIDGES...MAY BEGIN TO LIFT NORTHWARD...TO THE EAST OF
THE SOUTH ATLANTIC COAST. BUT...ANOTHER CIRCULATION IS PROGGED TO
DEVELOP WITHIN THIS REGIME...ACROSS EASTERN GULF COASTAL AREAS.

..PAC NW COAST STATES INTO NORTHERN INTERMOUNTAIN REGION...
MODELS INDICATE THAT 50-70 KT WEST SOUTHWESTERLY 500 MB FLOW WILL
PRECEDE THE SHORT WAVE IMPULSE. AND...THIS IS EXPECTED TO
CONTRIBUTE TO STRONG DEEP LAYER SHEAR SUFFICIENT FOR UPDRAFT
ROTATION...WITHIN PRE-FRONTAL ENVIRONMENT FROM EASTERN
OREGON/SOUTHEAST WASHINGTON INTO IDAHO...BY FRIDAY AFTERNOON. AS IS
TYPICALLY THE CASE ACROSS THIS REGION...UNCERTAINTY EXISTS
CONCERNING THE MAGNITUDE OF MOISTURE/DESTABILIZATION AVAILABLE FOR
MORE SIGNIFICANT CONVECTIVE POTENTIAL AT THIS EXTENDED TIME FRAME.
MOST GUIDANCE CURRENTLY INDICATES THAT CAPE WILL GENERALLY REMAIN AT
OR BELOW 500 J/KG. HOWEVER...POTENTIAL EXISTS FOR AT LEAST WIDELY
SCATTERED STRONG/SEVERE STORMS LATE FRIDAY AFTERNOON/EARLY FRIDAY
EVENING...POSSIBLY INCLUDING AN ISOLATED SUPERCELL OR TWO...WITH
ASSOCIATED ENHANCED SEVERE THREATS.

..EASTERN STATES...
THUNDERSTORMS WILL PROBABLY DEVELOP FRIDAY IN THE VICINITY OF THE
FRONTAL ZONE ASSOCIATED WITH THE UPPER POLAR TROUGH...FROM PARTS OF
SOUTHERN NEW ENGLAND AND THE NORTHERN MID ATLANTIC COAST STATES
THROUGH THE CENTRAL APPALACHIANS AND CUMBERLAND PLATEAU.
HOWEVER...THE MOST SIGNIFICANT CONVECTIVE DEVELOPMENT DURING THIS
PERIOD MAY BECOME FOCUSED NEAR THE MID-LEVEL CLOSED LOW OVER EASTERN
GULF COASTAL AREAS AND PARTS OF THE FLORIDA PENINSULA.

.KERR.. 08/30/2007

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