SWODY2
SPC AC 171730
DAY 2 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
1230 PM CDT SAT MAR 17 2012
VALID 181200Z - 191200Z
...THERE IS A SLGT RISK OF SVR TSTMS ACROSS PARTS OF THE SRN AND
CENTRAL PLAINS...
...SYNOPSIS...
LARGE-SCALE RIDGING ALOFT...WITH SOME STRENGTHENING...WILL PREVAIL
ACROSS THE ERN HALF OF THE CONUS ON SUNDAY...AS A STRONG/EXPANSIVE
TROUGH AFFECTING MOST OF WRN NOAM WILL ADVANCE SLOWLY EWD ACROSS THE
GREAT BASIN AND INTERMOUNTAIN WEST. HEIGHT FALLS ASSOCIATED WITH
THIS SYSTEM WILL BEGIN OVERSPREADING THE PLAINS...SUPPORTING
EVENTUAL DEVELOPMENT OF STRONG/SEVERE CONVECTION E OF THE MOUNTAINS.
MEANWHILE...A WEAKER MIDLEVEL SHORTWAVE TROUGH/SPEED MAX EMBEDDED
WITHIN A SUBTROPICAL JET EMANATING FROM SW OF BAJA IS EXPECTED TO
TRACK NEWD FROM SW TX THROUGH OK/KS AND REACH THE UPPER MS VALLEY BY
LATE SUNDAY NIGHT/EARLY MONDAY MORNING.
AT THE SURFACE...A CONSOLIDATING/STRENGTHENING LOW SHOULD MOVE NEWD
REACHING WRN ND LATE. A TRAILING N-S COLD FRONT WILL MOVE INTO THE
HIGH PLAINS DURING THE SECOND HALF OF THE PERIOD...BUT THE PRIMARY
FOCUS FOR THE MORE ROBUST CONVECTIVE ACTIVITY WILL BE A DRYLINE
EXPECTED ACROSS THE CENTRAL/SRN HIGH PLAINS DURING THE AFTERNOON.
...CENTRAL AND SRN PLAINS...
MODELS CONTINUE TO SUGGEST AN AREA OF SHOWERS AND TSTMS SHOULD
DEVELOP SUNDAY AFTERNOON WELL E OF THE DRY LINE...FROM CENTRAL AND E
TX/OK/KS INTO MO/AR THROUGH THE EVENING...ATTENDANT TO ASCENT WITH
THE SUBTROPICAL SHORTWAVE TROUGH/50 KT SPEED MAX. DESPITE THE LACK
OF MIDLEVEL COOLING...FORECAST SOUNDINGS SUGGEST LOW LEVEL
MOISTENING AND SOME SURFACE HEATING WILL PROVE SUFFICIENT TO WEAKEN
A CAP OVER THE ERN PORTION OF THE SRN/CENTRAL PLAINS FOR TSTM
DEVELOPMENT. MARGINAL INSTABILITY /MLCAPE OF 500-1000 J PER KG/ AND
STRENGTHENING BULK SHEAR PER 50 KT MIDLEVEL JET SUGGEST AN ISOLATED
THREAT FOR STRONG TO SEVERE STORMS WILL BE POSSIBLE OVER CENTRAL/E
TX THROUGH OK TO CENTRAL/ERN KS. LOW SEVERE WEATHER PROBABILITIES
HAVE BEEN EXPANDED EWD SOME TO ACCOUNT FOR A GREATER AREAL COVERAGE
OF THIS LOW END SEVERE THREAT.
MEANWHILE...MODELS CONTINUE TO INDICATE A MORE POTENT SEVERE WEATHER
ENVIRONMENT SHOULD BE EVOLVING ACROSS THE CENTRAL AND SRN HIGH
PLAINS SUNDAY AFTERNOON...AS HEATING ALONG AND AHEAD OF THE DRYLINE
RESULTS IN MODERATE DESTABILIZATION. BY 18/21Z-19/00Z...THE DRY LINE
SHOULD EXTEND FROM CENTRAL NEB THROUGH THE ERN EXTENT OF THE TX
PANHANDLE TO SWRN TX /INVOF VAL VERDE COUNTY/. HEIGHT FALLS
SPREADING SLOWLY EWD ATOP THE DRYLINE WILL SUPPORT INCREASING
ASCENT FOCUSED ALONG THIS BOUNDARY RESULTING IN AFTERNOON STORM
DEVELOPMENT...POTENTIALLY BY 18/21Z...FROM W TX TO WRN KS. WITH
TIME...COVERAGE OF CONVECTION SHOULD INCREASE...PARTICULARLY THROUGH
THE EVENING AS GREATER HEIGHT FALLS/STRONGER ASCENT OVERSPREAD THE
SRN HIGH PLAINS AFTER DARK.
AS THE SYSTEM SHIFTS EWD...FLOW ALOFT WILL CONTINUE TO STRENGTHEN
AND BECOME INCREASINGLY MERIDIONAL WITH NWD EXTENT. S/SWLY FLOW AT
MID LEVELS FROM KS SWD ATOP SSELY BOUNDARY LAYER FLOW AHEAD OF THE
DRYLINE WILL RESULT IN A FAVORABLY-SHEARED ENVIRONMENT...SUPPORTIVE
OF RAPIDLY STRENGTHENING SUPERCELL STORMS. TORNADOES AND HAIL...SOME
VERY LARGE...WILL BE ATTENDANT TO THE INITIAL...MORE DISCRETE...
STORMS. THESE THREATS COMBINED WITH A CONTINUED SEVERE WEATHER
THREAT AS ACTIVITY EVOLVES AFTER DARK INTO A MORE LINEAR MODE
MAINTAINS A RELATIVELY NARROW CORRIDOR OF A HIGHER-END SLIGHT RISK.
..PETERS.. 03/17/2012
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-
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