SWODY2
SPC AC 260600
DAY 2 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
1200 AM CST FRI DEC 26 2008
VALID 271200Z - 281200Z
...THERE IS A SLGT RISK OF SVR TSTMS FROM THE LOWER OH VALLEY REGION
SSWWD INTO NERN TX/NRN LA/NRN AND WRN MS...
...SYNOPSIS...
A LARGE MID-LEVEL TROUGH WILL MOVE SLOWLY EWD ACROSS THE CENTRAL
THIRD OF THE CONUS THIS PERIOD...WHILE AN EMBEDDED
SHORTER-WAVELENGTH TROUGH MOVES QUICKLY NEWD FROM NM TO THE UPPER MS
VALLEY/UPPER GREAT LAKES REGION BY 28/12Z.
AT THE SURFACE...A FRONT SHOULD STRETCH FROM THE UPPER MS VALLEY
SSWWD INTO ERN OK/CENTRAL TX AT THE START OF THE PERIOD. A FRONTAL
WAVE IS PROGGED TO BEGIN DEEPENING OVER MO AROUND MIDDAY...AND THEN
SHOULD SHIFT NNEWD ALONG THE FRONT TO THE UPPER GREAT LAKES REGION
LATE. THE TRAILING FRONT IS EXPECTED TO SURGE EWD AS THE LOW
DEEPENS NEWD ALONG THE BOUNDARY...CROSSING THE MS/TN/OH VALLEYS AND
APPROACHING THE WRN APPALACHIANS THROUGH THE END OF THE PERIOD.
...LOWER OH/LOWER AND MID MS VALLEYS WWD TO ERN PARTS OF OK/TX...
SHOWERS AND THUNDERSTORMS ONGOING AT THE START OF THE PERIOD ALONG
THE FRONT FROM MO SSWWD ACROSS ERN OK INTO TX WILL PROGRESS EWD
THROUGH THE MORNING...ALONG WITH ACCOMPANYING SEVERE POTENTIAL.
LITTLE DESTABILIZATION IS FORECAST DURING THE DAY DESPITE THE MOIST
PRE-FRONTAL BOUNDARY LAYER IN PLACE ACROSS THE S CENTRAL CONUS...AS
VERY WEAK LAPSE RATES WILL SUPPORT GENERALLY LESS THAN 500 J/KG
MIXED-LAYER CAPE.
NONETHELESS...WITH FLOW VEERING WEAKLY FROM SLY TO SSWLY WHILE
STRENGTHENING QUICKLY WITH HEIGHT THROUGH THE LOWER
TROPOSPHERE...SHEAR WILL BE MORE THAN SUFFICIENT FOR UPDRAFT
ORGANIZATION/ROTATION. GIVEN THE LACK OF INSTABILITY...AND
LINGERING WARM AIR IN THE LOWER TROPOSPHERE WHICH WILL LIKELY
REQUIRE CONSIDERABLE ASCENT TO ERODE...IT APPEARS THAT MOST OF DEEP
CONVECTION WILL BE CONFINED TO THE FRONTAL ZONE -- AND THUS A
PRIMARILY LINEAR STORM MODE IS ANTICIPATED. SHEAR WILL CERTAINLY BE
SUFFICIENT FOR EMBEDDED ROTATION AND/OR BOWING SEGMENTS WITHIN THE
LARGER-SCALE LINE...AND THUS LOCALLY-ENHANCED AREAS OF SEVERE THREAT
WILL LIKELY EXIST. AGAIN HOWEVER...THE OVERALL THREAT SHOULD REMAIN
CONSTRAINED TO SOME EXTENT BY THE GENERAL LACK OF FAVORABLE
INSTABILITY. ATTM...WILL INTRODUCE A 30% SEVERE PROBABILITY ACROSS
AR/SERN MO AND VICINITY -- WITHIN THE LARGER SLIGHT RISK AREA...AS
THIS REGION SHOULD EXPERIENCE THE GREATEST POTENTIAL FOR DAMAGING
WINDS AND ISOLATED TORNADOES THROUGH THE AFTERNOON.
A FRONTAL SQUALL LINE SHOULD CONTINUE THROUGH THE OVERNIGHT
HOURS...AS THE BOUNDARY SURGES E OF THE MS VALLEY. HOWEVER...EXPECT
THE SEVERE THREAT TO STEADILY WANE OVERNIGHT...AS WEAKER INSTABILITY
SUGGESTS A SLOW DECREASE IN CONVECTIVE INTENSITY.
..GOSS.. 12/26/2008
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-
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