SWODY2
SPC AC 090540
DAY 2 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
1240 AM CDT SAT OCT 09 2010
VALID 101200Z - 111200Z
...THERE IS A SLGT RISK OF SVR TSTMS FROM NWRN TX INTO WRN AND CNTRL
OK...
...SYNOPSIS...
UPPER LOW NOW MOVING INTO THE CNTRL AND NRN HIGH PLAINS WILL REMAIN
CUTOFF FROM THE FASTER POLAR WLYS WITH A REX BLOCK PATTERN BECOMING
ESTABLISHED OVER THE CNTRL STATES. SEVERAL VORTICITY MAXIMA WILL
ROTATE AROUND THE LOW CENTER...AND MODEL CONSENSUS IS THAT A STRONG
VORT MAX WILL DROP SSEWD THROUGH THE HIGH PLAINS INTO OK AND NWRN TX
SUNDAY AFTERNOON WITH GENERALLY SWD DRIFT OF UPPER LOW CENTER. THE
FRONT CURRENTLY ADVANCING SWD THROUGH THE CNTRL HIGH PLAINS WILL
EVENTUALLY STALL ACROSS THE TX PANHANDLE AND OK. ANOTHER FRONTAL
SURGE ACCOMPANYING THE VORT MAX DROPPING SWD ALONG THE WRN PERIPHERY
OF THE UPPER LOW CIRCULATION WILL REACH THE TX PANHANDLE AND OK
SUNDAY. FARTHER NORTH A QUASI-STATIONARY FRONT WILL STRETCH ACROSS
THE UPPER MS VALLEY...GREAT LAKES INTO THE OH VALLEY REGION.
...OK AND NRN TX...
LACK OF A STRONG LOW-LEVEL JET WILL LIMIT MOISTURE RETURN THROUGH
THE SRN PLAINS...BUT MODEST SLY BOUNDARY LAYER FLOW WILL RESULT IN
AN AXIS OF UPPER 40S TO NEAR 50 F DEWPOINTS RETURNING NWD INTO OK BY
SUNDAY. PLUME OF STEEP MID-LEVEL LAPSE RATES WILL DEVELOP OVER THE
WARM SECTOR WHICH ALONG WITH DIABATIC HEATING WILL CONTRIBUTE TO AN
AXIS OF 500-1000 J/KG MLCAPE FROM NWRN TX THROUGH WRN AND CNTRL OK.
A FEW ELEVATED STORMS WILL BE POSSIBLE WITHIN ZONE OF WEAK
ISENTROPIC LIFT NORTH OF STALLED BOUNDARY FROM NRN OK...TX PANHANDLE
INTO SRN KS SUNDAY MORNING. ACTIVITY COULD POSE A RISK FOR
MARGINALLY SEVERE HAIL. POTENTIAL FOR SURFACE BASED STORMS WILL
INCREASE FARTHER SOUTH WITHIN ZONE OF FORCING ACCOMPANYING THE SEWD
ADVANCING VORT MAX AND SECONDARY FRONTAL SURGE. THOUGH MOISTURE AND
INSTABILITY WILL BE SOMEWHAT LIMITED...STEEP LAPSE RATES WITH COLD
AIR ALOFT /-14 TO -15 C/ AT 500 MB ALONG WITH INCREASING 35-40 KT
VERTICAL SHEAR WILL PROMOTE A THREAT OF UPDRAFT ROTATION AND LARGE
HAIL. INVERTED-V BOUNDARY LAYERS INDICATE STORMS WILL LIKELY BECOME
OUTFLOW DOMINANT WITH A THREAT OF ISOLATED STRONG TO DAMAGING WIND
GUSTS THROUGH MID EVENING.
...CNTRL PLAINS THROUGH UPPER MS VALLEY...
COLD TEMPERATURES ALOFT IN VICINITY OF THE UPPER LOW AND DIABATIC
WARMING WILL ONCE AGAIN RESULT IN DESTABILIZATION DURING THE
DAY...BUT MLCAPE WILL LIKELY REMAIN SOMEWHAT MARGINAL DUE TO MODEST
LOW LEVEL MOISTURE. POTENTIAL WILL EXIST FOR A FEW THUNDERSTORMS TO
DEVELOP IN ASSOCIATION WITH IMPULSES ROTATING THROUGH UPPER LOW
CIRCULATION. THUNDERSTORMS WILL LIKELY BE MOST NUMEROUS IN VICINITY
OF SEWD ADVANCING FRONT FROM SD INTO PARTS OF NEB. THE STRONGER
STORMS COULD POSE A LOW END RISK OF ISOLATED STRONG WIND GUSTS AND
HAIL. EXPECTED MARGINAL INSTABILITY AND WEAK VERTICAL SHEAR WILL
LIKELY LIMIT POTENTIAL FOR A MORE ROBUST SEVERE THREAT.
...UPPER MS VALLEY...GREAT LAKES AND OH VALLEY...
COOL TEMPERATURES ALOFT...SURFACE DEWPOINTS IN THE 50S AND STEEP
LAPSE RATES WILL LIKELY CHARACTERIZE THE ATMOSPHERE IN VICINITY OF
NW-SE ORIENTED FRONT. AMPLIFICATION OF UPPER TROUGH CENTERED OVER
ERN CANADA WILL RESULT IN A BELT OF 30-35 KT DEEP LAYER FLOW FROM
THE GREAT LAKES SEWD INTO THE OH VALLEY REGION. WITH THE EXCEPTION
OF MODEST ISENTROPIC LIFT AND CONVERGENCE ALONG THE BAROCLINIC
ZONE...DEEPER FORCING FOR ASCENT WILL REMAIN WEAK AND AS A RESULT
COVERAGE OF STORMS WILL PROBABLY REMAIN SOMEWHAT LIMITED.
NEVERTHELESS...ANY STORMS THAT DO DEVELOP MAY POSE A RISK FOR
ISOLATED STRONG TO DAMAGING WIND GUSTS AND HAIL THROUGH EARLY
EVENING.
..DIAL.. 10/09/2010
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