DAY1SVR: Day 1 Convective Outlook

ACUS01 KWNS 191250
SWODY1
SPC AC 191248

DAY 1 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
0748 AM CDT SAT MAY 19 2012

VALID 191300Z - 201200Z

...THERE IS A SLGT RISK OF SVR TSTMS OVER PARTS OF THE CNTRL AND SRN
PLNS...

...SYNOPSIS...
TROUGH NOW EXTENDING FROM SK SWD TO THE SRN RCKYS EXPECTED TO MOVE
STEADILY E/NE THIS PERIOD AS RIDGE REMAINS IN PLACE FROM TX THROUGH
THE MID MS VLY TO THE LWR GRT LKS. ELSEWHERE...ELONGATED TROUGH
COMPLEX WILL PERSIST OVER GA AND THE CAROLINAS...WHILE MODERATE WLY
FLOW OVERSPREADS THE WEST.

SRN PORTION OF THE RCKYS TROUGH...MARKED BY SHORTWAVE IMPULSE NOW
OVER SRN CO...SHOULD MOVE NE INTO CNTRL KS/S CNTRL NEB THIS
EVE...AND INTO SW MN/NW IA BY 12Z SUN. THIS FEATURE SHOULD SERVE TO
ACCELERATE COLD FRONT NOW OVER THE CNTRL HI PLNS SSEWD...WITH THE
FRONT OVERTAKING LEE TROUGH/DRY LINE NOW EXTENDING SSW FROM WRN KS
INTO THE OK/TX PANHANDLES. AT THE SAME TIME...NE MOVEMENT OF CO
IMPULSE SHOULD IMPART A CORRESPONDING NEWD MOTION TO WRN KS SFC
WAVE...WITH THE WAVE REACHING SE NEB THIS EVE...AND SE MN EARLY SUN.

THE COLD FRONT/LEE TROUGH WILL BE THE FOCUS FOR STRONG TO SVR TSTM
DEVELOPMENT OVER PARTS OF THE CNTRL AND SRN PLNS LATER TODAY INTO
TNGT AS SFC HEATING AND LARGE SCALE ASCENT DESTABILIZE REGION.

...E TX PNHDL/WRN OK INTO ERN NEB/WRN IA TODAY/TNGT...
PERSISTENT LOW LVL SLY FLOW AHEAD OF COLD FRONT/LEE TROUGH WILL
CONTRIBUTE TO FURTHER MOISTENING OVER ERN PORTIONS OF THE SRN AND
CNTRL PLNS TODAY. HOWEVER...SFC DATA /ESPECIALLY CONTINUING
PRESENCE OF RIDGING OVER THE WRN GULF OF MEXICO/ AND BLENDED PW DATA
SUGGEST THAT MAGNITUDE OF MOISTURE RETURN WILL REMAIN MODEST. THIS
FACTOR WILL ONCE AGAIN LIMIT DEGREE OF DIURNAL DESTABILIZATION
ALONG/AHEAD OF FRONT. NEVERTHELESS...GIVEN BROAD/DEEP EML...AMPLE
SBCAPE /1500-2500 J PER KG/ LIKELY WILL DEVELOP TO SUPPORT AN
INCREASING RISK FOR SVR STORMS LATER TODAY OVER PARTS OF THE
CNTRL/SRN PLNS AND THE MID MO VLY.

BAND OF STORMS NOW PRESENT FROM NW IA SWD INTO NW MO/ERN KS MARKS
THE LEADING EDGE OF THE EML AND ASSOCIATED WAA. ALTHOUGH THEY MAY
YIELD A SPOT OR TWO OF HAIL...THE TSTMS SHOULD DIMINISH LATER THIS
MORNING AS ASSOCIATED LLJ WEAKENS AND BACKS. NEW STORMS...WITH A
GREATER SVR POTENTIAL...SHOULD FORM BY MID-LATE AFTN ALONG FRONT/LEE
TROUGH FROM S CNTRL NEB SWD INTO THE ERN TX PANHANDLE AS FORCING FOR
ASCENT WITH EJECTING UPR IMPULSE AND SFC HEATING OVERCOME EML CAP.

MODEST MOISTURE AVAILABILITY /MAX SFC DEWPOINTS AROUND 60 F/ WILL
LIMIT BUOYANCY. BUT 40+ KT SWLY 500 MB JET ASSOCIATED WITH
CO UPR IMPULSE AND CONTINUING PRESENCE OF 35 KT SLY LLJ WILL YIELD
AMPLE DEEP SHEAR FOR SUSTAINED STORMS/SUPERCELLS. A FEW OF THESE
MAY REMAIN DISCRETE FOR AN HOUR OR TWO LATE THIS AFTN/EARLY THIS
EVE...POSING A RISK FOR LARGE HAIL...LOCALLY DMGG WIND...AND PERHAPS
A COUPLE TORNADOES. THE STORMS SHOULD...HOWEVER...MORE GENERALLY
EVOLVE INTO A FAIRLY LENGTHY SQLN BY EVE. THIS ACTIVITY WILL POSE A
CONTINUED RISK FOR SVR HAIL AND COULD PRODUCE A BROADER SWATH OR TWO
OF DMGG WIND INTO TNGT AS THE COLD POOLS CONSOLIDATE/STRENGTHEN.
THE SVR THREAT SHOULD DIMINISH LATER TNGT AS THE BOUNDARY LAYER
COOLS AND UPR IMPULSE CONTINUES NEWD BEYOND NARROW AXIS OF MOISTURE
RETURN.

...SRN/CNTRL FL THIS AFTN...
CONTINUING PRESENCE OF MODERATE WLY HI-LVL JET...COOL MID LVL TEMPS
/AROUND MINUS 10 C AT 500 MB/...AND HI PW /AOA 1.50 INCHES/ MAY
SUPPORT ANOTHER ROUND OF STRONG TO SVR DIURNAL STORMS WITH LOCALLY
DMGG WIND/SVR HAIL OVER SRN AND PERHAPS S CNTRL FL. WITH THE
BACKGROUND LOW TO MID LVL FLOW ENELY TODAY /RELATIVE TO WLY
YESTERDAY/...SWRN PARTS OF THE PENINSULA MAY BE MOST FAVORED FOR
STORMS. WV IMAGERY SUGGESTS THAT DEVELOPMENT ALSO MAY BE ENHANCED
BY APPARENT LOW AMPLITUDE UPR IMPULSE APPROACHING THE SW FL CST.

...TN VLY/N GA AREA THIS AFTN...
WRN EXTENSION OF LONG-LIVED...CAROLINAS UPR TROUGH WILL MAINTAIN
CORRIDOR OF COOL MID LVL TEMPS /AOB MINUS 14 C AT 500 MB/ ATOP
STRONGLY-HEATED...RELATIVELY MOIST...VERY WEAKLY SHEARED ENVIRONMENT
OVER PARTS OF TN AND THE WRN SLOPES OF THE SRN APPALACHIANS. THIS
SETUP MAY YIELD SCTD DIURNAL PULSE STORMS WITH ISOLD WET MICROBURSTS
AND/OR SVR HAIL.

..CORFIDI/COHEN.. 05/19/2012

+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-
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.