SWODY1
SPC AC 270557
DAY 1 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
1157 PM CST FRI DEC 26 2008
VALID 271200Z - 281200Z
...THERE IS A SLGT RISK OF SVR TSTMS ACROSS PARTS OF THE SRN
PLAINS...OZARK PLATEAU AND LOWER TO MID-MS VALLEY...
...SRN PLAINS/OZARK PLATEAU/LOWER TO MID-MS VALLEY...
A WELL-DEVELOPED UPPER-LEVEL TROUGH LOCATED ACROSS THE FOUR CORNERS
REGION WILL MOVE EWD ACROSS THE ROCKIES AND INTO THE GREAT PLAINS
TODAY. AHEAD OF THE SYSTEM...THE CENTER OF A BROAD 50 TO 65 KT
LOW-LEVEL JET WILL MOVE NNEWD ACROSS THE OZARK PLATEAU AROUND MIDDAY
AND INTO THE LOWER OH VALLEY BY LATE THIS AFTERNOON. WEST OF THE
LOW-LEVEL JET...MODEL FORECASTS ARE IN AGREEMENT WITH A
WELL-ORGANIZED SQUALL-LINE ONGOING AT 12Z THIS MORNING WITH THE LINE
ADVANCING EWD ACROSS WRN MO...ERN OK AND NE TX THIS MORNING. THE
SQUALL-LINE SHOULD REACH ERN MO...ERN AR AND WRN LA BY LATE THIS
AFTERNOON AND MAY WEAKEN SOME AS THE LOW-LEVEL JET MOVES NNEWD AWAY
FROM THE REGION.
FORECAST SOUNDINGS ACROSS THE SRN PLAINS AND OZARK PLATEAU SHOW VERY
STRONG VERTICAL SHEAR PROFILES AT 12Z TO 15Z WITH 0-6 KM SHEAR
VALUES GENERALLY RANGING FROM AROUND 50 KT OVER EAST TX AND LA TO
ABOVE 80 KT OVER SE KS AND PARTS OF WRN MO. ALTHOUGH THE MODELS SHOW
MLCAPE VALUES GENERALLY BELOW 750 J/KG...THE STRONG VERTICAL SHEAR
COMBINED WITH ENHANCED LARGE-SCALE ASCENT ASSOCIATED WITH THE
APPROACHING UPPER-LEVEL TROUGH...LIFT ALONG THE WRN EDGE OF THE
LOW-LEVEL JET AND STRONG LOW-LEVEL CONVERGENCE SHOULD SUPPORT A
SEVERE LINEAR MCS THIS MORNING. FORECAST SOUNDINGS ALSO SHOW 50-60
KT OF FLOW AT 1 KM ACROSS THE CNTRL PART OF THE SLIGHT RISK AREA
SUGGESTING A MORE WIDESPREAD WIND DAMAGE THREAT MAY EXIST AS THE
SQUALL-LINE ADVANCES EWD ACROSS THE OZARK PLATEAU. A FEW TORNADOES
MAY OCCUR IN THE LINE ITSELF OR WITH ISOLATED SUPERCELLS THAT
DEVELOP AHEAD OF THE LINE. FURTHER NNE ACROSS THE MID-MS
VALLEY...FORECAST SOUNDINGS SUGGEST THE STORMS WILL LIKELY BE
SLIGHTLY ELEVATED SUGGESTING THE WIND DAMAGE THREAT SHOULD NOT BE AS
WIDESPREAD FROM CNTRL MO EWD ACROSS SRN IL.
THE SQUALL-LINE WILL ALSO AFFECT AREAS SOUTH ACROSS SRN AR...EAST TX
AND WRN LA. ALTHOUGH INSTABILITY MAY BE A BIT STRONGER THAN AREAS TO
THE NORTH...FORECAST SOUNDINGS ACROSS THE REGION SUGGEST LOW-LEVEL
FLOW WILL WEAKEN WITH TIME LATE THIS MORNING INTO THE EARLY
AFTERNOON. THIS SUGGESTS...THE WIND DAMAGE THREAT SHOULD GRADUALLY
BECOME MORE ISOLATED AS THE LINE ADVANCES INTO THE LOWER MS VALLEY
THIS AFTERNOON. ALTHOUGH THE SQUALL-LINE SHOULD CONTINUE EWD ACROSS
MS AND WRN TN THIS EVENING INTO THE OVERNIGHT PERIOD...WEAK
INSTABILITY AND DECREASING LOW-LEVEL FLOW SHOULD KEEP ANY SEVERE
THREAT MARGINAL.
..BROYLES.. 12/27/2008
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-
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