SPC AC 051941
DAY 1 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
0241 PM CDT THU OCT 05 2006
VALID 052000Z - 061200Z
...THERE IS A SLGT RISK OF SVR TSTMS LATE THIS AFTN ACROSS PARTS OF
THE GREAT BASIN/NRN INTERMOUNTAIN REGION....
...INTERMOUNTAIN WEST...
THE MOST SIGNIFICANT SHORT WAVE IMPULSE ASSOCIATED WITH THE WESTERN
U.S. UPPER TROUGH STILL APPEARS TO BE DIGGING AROUND THE
SOUTHWESTERN PERIPHERY OF A CLOSED LOW NEAR THE CENTRAL CALIFORNIA
COAST. HOWEVER...DEEP LAYER SOUTHERLY FLOW AHEAD OF LARGE SCALE
TROUGH AXIS CONTINUES TO TRANSPORT MOISTURE NORTHWARD FROM THE LOWER
LATITUDE EASTERN PACIFIC...TOWARD THE SOUTHERN PLATEAU/GREAT BASIN.
INCREASING MOISTURE/OROGRAPHY AND FURTHER SURFACE HEATING IS
EXPECTED TO CONTRIBUTE TO SUBSTANTIAL CONVECTIVE DEVELOPMENT LATE
THIS AFTERNOON FROM PARTS OF ARIZONA INTO SOUTHERN/EASTERN PORTIONS
OF THE GREAT BASIN. ENHANCED BY FAVORABLE DEEP LAYER SHEAR BENEATH
40-50 KT SOUTHWESTERLY MID-LEVEL FLOW..A LOCALIZED SEVERE THREAT
WILL EXIST IN STRONGER CELLS...WITH RELATIVELY WEAK DESTABILIZATION
THE PRIMARY LIMITING FACTOR TO CONVECTIVE POTENTIAL.
IT APPEARS THAT THE BEST POTENTIAL FOR SEVERE STORMS MAY BE FROM
PARTS OF NORTHEAST NEVADA/EXTREME NORTHWEST UTAH INTO SOUTHWESTERN
IDAHO...WHERE LOW-LEVEL MOISTURE TRANSPORT IS FOCUSED BENEATH
NORTHEASTERN FRINGE OF MID-LEVEL DRY SLOT. THOUGH MID-LEVEL FORCING
FOR UPWARD VERTICAL MOTION IS UNCERTAIN...DIFLUENCE ALOFT MAY
ENHANCE STORM DEVELOPMENT. AND...WITH MIXED LAYER CAPE POSSIBLY AS
HIGH AS 500-1000 J/KG...HODOGRAPHS ARE SUFFICIENT FOR ISOLATED
SUPERCELLS THROUGH EARLY EVENING.
...TENNESSEE VALLEY INTO MID ATLANTIC STATES...
MOIST AIR MASS ALONG STALLED FRONTAL ZONE HAS HEATED AND BECOME WEAK
TO LOCALLY MODERATELY UNSTABLE...SUPPORTIVE OF CONVECTIVE
DEVELOPMENT. FAVORABLE OROGRAPHY ALONG THE SOUTHERN/CENTRAL
APPALACHIANS IS SUPPORTING ADDITIONAL ACTIVITY...WHICH LIKELY WILL
INCREASE FURTHER LATE THIS AFTERNOON. WELL TO THE SOUTHEAST OF A
SHORT WAVE TROUGH DIGGING ACROSS THE GREAT LAKES REGION...FLOW
FIELDS/SHEAR ARE WEAK...BUT UNSATURATED THERMODYNAMIC PROFILES COULD
CONTRIBUTE TO ISOLATED DOWNBURSTS IN STRONGER STORMS THROUGH EARLY
EVENING. SCATTERED STORMS MAY PERSIST ALONG FRONT AS IT PRESSES
SOUTHEAST OF THE CENTRAL/SOUTHERN APPALACHIANS LATER TONIGHT...WITH
CONTINUED SOUTHEASTWARD PROGRESSION OF UPSTREAM TROUGH.
..KERR.. 10/05/2006
CLICK TO GET WUUS01 PTSDY1 PRODUCT
NOTE: THE NEXT DAY 1 OUTLOOK IS SCHEDULED BY 0100Z
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