SWODY3
SPC AC 240744
DAY 3 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
0244 AM CDT FRI APR 24 2009
VALID 261200Z - 271200Z
...THERE IS A SLGT RISK OF SVR TSTMS FROM PARTS OF THE SRN AND CNTRL
PLAINS INTO THE MID-UPPER MS VALLEY REGION...
...SYNOPSIS...
SIGNIFICANT MODEL DIFFERENCES ARE EVIDENT FOR SUNDAY REGARDING THE
DETAILS OF HOW THE UPPER TROUGH THAT WILL BOTTOM OUT NEAR THE FOUR
CORNERS EVOLVES AS IT MOVES INTO THE PLAINS. GFS AND ECMWF EJECT A
SIGNIFICANT SHORTWAVE TROUGH OUT OF BASE OF TROUGH NNEWD INTO THE
NRN PLAINS DURING THE DAY...LEAVING A WEAKER POSITIVE TILT TROUGH
FARTHER SOUTH THAT MOVES INTO THE CNTRL AND SRN PLAINS SUNDAY
EVENING AND OVERNIGHT. NAM SOLUTIONS EJECT THE INITIAL SHORTWAVE
MUCH FARTHER SOUTH ACROSS THE CNTRL AND SRN PLAINS SUNDAY AFTERNOON.
IN EITHER CASE...THE PRIMARY SEVERE THREAT IS EXPECTED ACROSS THE
CNTRL AND SRN PLAINS. HOWEVER...GFS AND ECMWF WOULD SUPPORT A SEVERE
THREAT FARTHER NORTH INTO THE UPPER MS VALLEY REGION.
AT THE SURFACE A WARM FRONT WILL LIKELY RETREAT NWD INTO THE UPPER
MS. DRYLINE WILL EXTEND N-S THROUGH W TX DURING THE AFTERNOON.
HOWEVER...THIS BOUNDARY WILL BE OVERTAKEN BY A PACIFIC FRONT SUNDAY
NIGHT. DETAILS REGARDING THE EVOLUTION OF SURFACE PATTERN DIFFER DUE
TO MODEL DIFFERENCES IN HANDLING EJECTING SHORTWAVE TROUGH.
...SRN AND CNTRL PLAINS...
ELEVATED STORMS WILL LIKELY BE ONGOING WITHIN ZONE OF ISENTROPIC
LIFT NORTH OF WARM FRONT OVER A PORTION OF THE CNTRL PLAINS. AN AXIS
OF RICHER LOW LEVEL MOISTURE WITH DEWPOINTS IN THE 60S WILL EXIST IN
WARM SECTOR SOUTH OF WARM FRONT AND EAST OF DRYLINE. PLUME OF STEEP
MID LEVEL LAPSE RATES WILL ADVECT EAST AND CONTRIBUTE TO AN AXIS OF
MODERATE INSTABILITY FROM WRN KS...WRN OK AND WRN TX AS LOW CLOUDS
MIX OUT AND THE BOUNDARY LAYER WARMS. THE WARM SECTOR WILL INITIALLY
BE CAPPED. HOWEVER...STORMS ARE EXPECTED TO DEVELOP ALONG CONVERGENT
DRYLINE AS IT MIXES EAST AND AS THE CAP WEAKENS BY LATE AFTERNOON.
BULK SHEAR OF 40-50 KT WILL SUPPORT SUPERCELLS AND 0-1 KM HODOGRAPH
SIZE WILL ALSO INCREASE AS THE LOW LEVEL JET STRENGTHENS DURING THE
EARLY EVENING. LARGE HAIL AND ISOLATED TORNADOES WILL BE THE INITIAL
PRIMARY THREATS. HOWEVER...STORMS MAY EVENTUALLY EVOLVE INTO ONE OR
MORE MCSS OVERNIGHT WITH THREAT TRANSITIONING TO ISOLATED DAMAGING
WIND AND HAIL.
...MID-UPPER MS VALLEY REGION...
EXTENT OF SEVERE THREAT IN THIS REGION IS MORE UNCERTAIN DUE TO
SIGNIFICANT MODEL DIFFERENCES. NEVERTHELESS...STORMS DEVELOPING
NORTH OF RETREATING WARM FRONT MAY POSE A THREAT FOR HAIL. AS THE
BOUNDARY LAYER WARMS AND DESTABILIZES...POTENTIAL FOR SURFACE BASED
STORMS MAY INCREASE DURING THE AFTERNOON. PRIMARY SEVERE THREATS IN
THIS REGION ARE EXPECTED TO BE ISOLATED DAMAGING WIND AND HAIL.
..DIAL.. 04/24/2009
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-
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