SWODY1
SPC AC 161630
DAY 1 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
1130 AM CDT FRI MAR 16 2012
VALID 161630Z - 171200Z
...THERE IS A SLGT RISK OF SVR TSTMS THIS AFTERNOON THROUGH EARLY
TONIGHT FOR W TX INTO WRN OK...
...W TX INTO WRN OK THIS AFTERNOON INTO EARLY TONIGHT...
MORNING WATER VAPOR IMAGERY SHOWS A WEAK SRN STREAM TROUGH MOVING
ENEWD OVER FAR W TX AND SRN NM...AND THIS WAVE WILL PROVIDE WEAK
BACKGROUND ASCENT AND A MODEST INCREASE IN MID-UPPER SWLY FLOW OVER
THE DRYLINE AND WARM SECTOR THIS AFTERNOON/EVENING. THE DRYLINE IS
EXPECTED TO MIX EWD TO NEAR THE CAPROCK BY 21Z FROM THE E/SE
PANHANDLE TO THE SOUTH PLAINS...AND WILL EXTEND SWD INTO THE TRANS
PECOS REGION OF W TX. AS SURFACE TEMPERATURES WARM INTO THE LOW-MID
80S ALONG THE DRYLINE...CONVECTIVE INHIBITION WILL WEAKEN AND
THUNDERSTORM DEVELOPMENT WILL BECOME MORE PROBABLE BY 21-00Z. GIVEN
BOUNDARY LAYER DEWPOINTS NEAR 60 F TO THE E OF THE
DRYLINE...MIDLEVEL LAPSE RATES NEAR 8.5 C/KM...MLCAPE OF 2500-3000
J/KG...AND A MARGINAL SUPERCELL WIND PROFILE...LARGE HAIL CAN BE
EXPECTED WITH ANY SUSTAINED STORMS. THE TORNADO THREAT APPEARS TO
BE SOMEWHAT MARGINAL GIVEN RELATIVELY WEAK LOW-LEVEL SHEAR IN THE
WARM SECTOR /ESRH OF 50-100 M2 PER S2/. OTHERWISE...A FEW DAMAGING
GUSTS WILL ALSO BE POSSIBLE LATER THIS EVENING INTO EARLY TONIGHT AS
ONE OR TWO CLUSTERS OF STORMS EVOLVE FROM THE INITIAL DRYLINE
CONVECTION AND SPREAD EWD INTO THE MOIST WARM SECTOR ACROSS THE
LOWER PLAINS.
...TN VALLEY REGION THIS AFTERNOON...
A REMNANT MCV FROM OVERNIGHT CONVECTION WILL CONTINUE TO DRIFT
EWD/ESEWD OVER WRN KY...WHILE THE OUTFLOW BOUNDARY ASSOCIATED WITH
THE CONVECTIVE CLUSTER MOVES SLOWLY SWD/SEWD ACROSS MIDDLE TN AND
NRN MS/AL. ADDITIONAL STORM DEVELOPMENT IS EXPECTED THIS AFTERNOON
ALONG THIS OUTFLOW BOUNDARY IN A MODERATELY UNSTABLE ENVIRONMENT
WITH MLCAPE OF 1500-2000 J/KG. THE INSTABILITY WILL SUPPORT STRONG
UPDRAFTS AND SOME HAIL RISK...AS WELL AS ISOLATED DOWNBURSTS WITH
HEAVY PRECIPITATION LOADING. STILL...RELATIVELY WEAK VERTICAL SHEAR
WILL CONTINUE TO LIMIT THE RISK FOR PERSISTENT SEVERE STORMS.
...MID MS VALLEY THIS AFTERNOON...
LOW-LEVEL WAA ON THE NW SIDE OF THE LOWER OH VALLEY MCV AND WEAK
SURFACE COLD POOL WILL CONTINUE TO SUPPORT THUNDERSTORM DEVELOPMENT
THROUGH THE AFTERNOON IN A N-S BAND FROM W CENTRAL IL INTO ERN MO.
A COMBINATION OF MODERATE INSTABILITY FEEDING THIS CONVECTION FROM
THE SW AND WEAK VERTICAL SHEAR WILL AGAIN SUPPORT MAINLY PULSE-TYPE
STORMS CAPABLE OF PRODUCING ISOLATED LARGE HAIL/STRONG OUTFLOW
GUSTS. FARTHER N/NW INTO IA...THERE IS LITTLE TO FOCUS STORM
DEVELOPMENT THIS AFTERNOON...DESPITE A SIMILAR THERMODYNAMIC
ENVIRONMENT COMPARED TO MO. THUS...WILL NOT EXTEND THE LOW
HAIL/WIND PROBABILITIES INTO IA...THOUGH VERY ISOLATED STORMS COULD
POSE SUCH A RISK.
...ERN NC/SE VA THIS AFTERNOON/EVENING...
A REMNANT MCV IS MOVING SLOWLY SEWD FROM WV TO VA...WHILE SURFACE
HEATING AND BOUNDARY LAYER DEWPOINTS AOA 60 F WILL CONTRIBUTE TO
POTENTIALLY MODERATE INSTABILITY ALONG AND E OF A DIFFUSE LEE TROUGH
IN NC/VA. A FEW THUNDERSTORMS COULD DEVELOP LATER THIS
AFTERNOON/EVENING AS THE MCV APPROACHES THE SURFACE TROUGH AND AREA
OF STRONGER INSTABILITY...AND ISOLATED STRONG/DAMAGING OUTFLOW GUSTS
WILL BE POSSIBLE.
...UPPER MI OVERNIGHT...
LOW-LEVEL MOISTURE AND STEEP MIDLEVEL LAPSE RATES WILL OVERSPREAD
THE UPPER GREAT LAKES LATE TODAY THROUGH TONIGHT IN A LOW-LEVEL WAA
REGIME. MODERATE ELEVATED INSTABILITY WILL DEVELOP OVER UPPER MI
TONIGHT...BUT STORM DEVELOPMENT/COVERAGE IS IN QUESTION. WILL
MAINTAIN THE LOW HAIL PROBABILITIES FOR NOW...BUT THIS AREA WILL BE
RE-EVALUATED IN LATER UPDATES.
..THOMPSON/LEITMAN.. 03/16/2012
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-
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