SWODY1
SPC AC 091933
DAY 1 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
0233 PM CDT THU OCT 09 2008
VALID 092000Z - 101200Z
...THERE IS A SLGT RISK OF SVR TSTMS LATE THIS AFTN ACROSS PARTS OF
SRN SC...SRN GA AND NRN/CNTRL FL....
...SOUTHEAST STATES...
THE CLOSED MID-LEVEL CIRCULATION CENTER HAS REDEVELOPED EAST
SOUTHEASTWARD INTO SOUTHWESTERN GEORGIA...IN RESPONSE TO THE
PROGRESSION OF AN IMPULSE AROUND ITS SOUTHERN/EASTERN PERIPHERY.
HOWEVER...CUT-OFF FROM THE STRONGER WESTERLIES...EASTWARD MOTION MAY
SLOW UNTIL PERHAPS PICKING UP A BIT THIS EVENING OR LATER TONIGHT AS
AN UPSTREAM RIDGE BEGINS TO BUILD IN ADVANCE OF AN AMPLIFYING TROUGH
ACROSS THE WESTERN STATES.
SLOWING OF THE LEADING EDGE OF STRONGER COOLING AHEAD OF THE
MID-LEVEL COLD CORE MAY HAVE CONTRIBUTED TO WEAKENING OF AN INITIAL
BROKEN BAND OF STORMS NOW SPREADING ACROSS PARTS OF SOUTH
CAROLINA/GEORGIA COASTAL AREAS INTO NORTHERN FLORIDA. BUT...NEW
DEVELOPMENT/INTENSIFICATION HAS BEEN ONGOING IN A LOW-LEVEL
CONFLUENCE ZONE AHEAD OF THIS ACTIVITY ACROSS THE NORTHERN
PENINSULA. AIDED BY MIXED LAYER CAPE OF 1000-2000 J/KG...IN THE
PRESENCE OF FAVORABLE DEEP LAYER SHEAR BENEATH 40+ KT WESTERLY 500
MB FLOW...VIGOROUS STORMS CAPABLE OF PRODUCING LARGE HAIL/LOCALIZED
DOWNBURSTS MAY CONTINUE ACROSS THE REMAINDER OF NORTHERN/CENTRAL
FLORIDA THIS AFTERNOON. LOW-LEVEL SHEAR IS RATHER WEAK...BUT
POTENTIAL FOR AN ISOLATED/BRIEF TORNADO COULD BECOME ENHANCED AS
STORMS INTERACT WITH THE SEA-BREEZE NEAR NORTHERN/CENTRAL FLORIDA
ATLANTIC COASTAL AREAS.
FARTHER NORTH...THERMODYNAMIC PROFILES MAY REMAIN FAVORABLE FOR
LARGE HAIL IN LINGERING STORMS IN CLOSER PROXIMITY TO THE
CIRCULATION CENTER ACROSS SOUTHERN GEORGIA THROUGH THE REMAINDER OF
THE AFTERNOON.
TO THE SOUTH...WEAKER CONVECTIVE INSTABILITY BENEATH A WARMER AND
MORE MOIST MID-LEVEL ENVIRONMENT...COUPLED WITH WEAKER DEEP LAYER
SHEAR...IS EXPECTED TO RESULT IN MORE LIMITED SEVERE POTENTIAL WITH
STORMS DEVELOPING ACROSS THE SOUTHERN PENINSULA.
...PARTS OF THE NORTH CENTRAL ROCKIES INTO THE NORTHERN PLAINS...
MOISTENING AND ASCENT IN AN ELEVATED WARM ADVECTION REGIME IS WELL
UNDERWAY NEAR THE CREST OF THE UPPER RIDGE BUILDING THROUGH THE
NORTHERN PLAINS. AS A MID/UPPER JET STRENGTHENS DOWNSTREAM OF THE
AMPLIFYING UPSTREAM TROUGH AXIS...STEEPENING ISENTROPIC LIFT BENEATH
INCREASINGLY DIVERGENT UPPER FLOW IS EXPECTED TO CONTRIBUTE TO
SUFFICIENT DESTABILIZATION FOR SCATTERED THUNDERSTORMS...MAINLY
AFTER 10/03Z...FROM PARTS OF NORTHEAST WYOMING THROUGH SOUTH DAKOTA.
...SOUTHERN PLATEAU INTO WEST TEXAS...
HIGHEST PROBABILITIES FOR THUNDERSTORMS STILL APPEAR LIKELY TO
REMAIN CONFINED TO THE MEXICAN PLATEAU...BUT MOISTURE RETURN AND
HEATING MAY CONTRIBUTE TO SUFFICIENT INSTABILITY FOR AFTERNOON/
EARLY EVENING STORMS ACROSS THE HIGHER TERRAIN NEAR THE
INTERNATIONAL BORDER AREA.
...PACIFIC NORTHWEST...
LOW-LEVEL ONSHORE FLOW IS WEAK...BUT MOISTENING IS ONGOING BENEATH A
MID-LEVEL THERMAL TROUGH WITH A 500 MB COLD CORE AT OR BELOW -30C.
THIS MAY CONTRIBUTE TO SUFFICIENT INSTABILITY FOR SCATTERED STORMS
ALONG COASTAL AREAS INTO THE WESTERN SLOPES OF THE CASCADES LATE
THIS AFTERNOON AND EVENING...PERHAPS ENHANCED BY FORCING ASSOCIATED
WITH A DIGGING IMPULSE WITHIN THE AMPLIFYING UPPER TROUGH.
..KERR.. 10/09/2008
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-
To unsubscribe from WX-STORM send e-mail to LISTSERV@LISTSERV.ILLINOIS.EDU with
"unsub wx-storm" in the body of your message. For more information write cnovy@cox.net.
No comments:
Post a Comment