SPC AC 060555
DAY 2 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
1255 AM CDT SUN NOV 06 2011
VALID 071200Z - 081200Z
...THERE IS A SLGT RISK OF SVR TSTMS ACROSS THE SRN PLAINS...
...SRN AND CNTRL PLAINS...
A FAIRLY POTENT LOOKING UPPER-LEVEL TROUGH WILL MOVE ACROSS THE
DESERT SOUTHWEST MONDAY AS A 60 TO 75 KT MID-LEVEL JET EJECTS NEWD
INTO THE GREAT PLAINS. WELL TO THE EAST OF THE TROUGH...A SFC LOW
WILL DEVELOP ACROSS WEST TX DURING THE DAY AS LOW-LEVEL SLY FLOW
INCREASES ACROSS THE SRN PLAINS. STRONG MOISTURE ADVECTION WILL
BRING SFC DEWPOINTS INTO THE LOWER 60S F ACROSS NORTH TX INTO CNTRL
OK WHERE SCATTERED THUNDERSTORMS MAY BE ONGOING MONDAY MORNING INTO
THE AFTERNOON IN THE REGION OF STRONG WARM ADVECTION. THE CONVECTIVE
COVERAGE SHOULD BE GREATEST ALONG THE AXIS OF THE LOW-LEVEL JET FROM
THE TX HILL COUNTRY NWD ACROSS NW TX INTO WCNTRL OK. FURTHER TO THE
WEST OF THE MIDDAY STORMS ON THE WRN EDGE OF THE LOW-LEVEL JET...THE
MODELS FORECAST MODERATE DESTABILIZATION WITH SBCAPE VALUES POSSIBLY
REACHING THE 1000 TO 1500 J/K RANGE BY LATE AFTERNOON. DUE TO THE
INSTABILITY AND STRONG LARGE-SCALE ASCENT MOVING OUT INTO THE SRN
PLAINS...DISCRETE CELL INITIATION SHOULD TAKE PLACE DURING THE EARLY
AFTERNOON WITH A RAPID INCREASE IN CONVECTIVE COVERAGE. ALTHOUGH THE
MODELS ALL DEVELOP STORMS...THE GFS IS MUCH MORE AGGRESSIVE
CONCERNING CONVECTIVE COVERAGE AND THIS SOLUTION SEEMS REASONABLE.
AT THIS POINT...IT APPEARS A SQUALL-LINE WILL DEVELOP IN WRN OK AND
NW TX AND MOVE EWD INTO WCNTRL OK AND ACROSS NORTH TX SIMILAR TO THE
GFS SOLUTION.
FORECAST SOUNDINGS ACROSS WCNTRL OK AND NORTHWEST TX ON TUESDAY
GRADUALLY INCREASE DEEP LAYER SHEAR PROFILES AS THE EXIT REGION OF
THE MID-LEVEL JET MOVES OUT INTO THE SRN PLAINS. WITH 0-6 KM SHEAR
VALUES AS HIGH AS 50 KT COMBINED WITH SUBSTANTIAL VEERING WITH
HEIGHT FROM THE SFC TO 850 MB SHOULD EASILY SUPPORT AN ORGANIZED
SEVERE THREAT. THE MAIN QUESTION IS STORM MODE. THE CURRENT THINKING
IS THAT SUPERCELLS MAY DEVELOP EARLY IN THE EVENT WITH A FAIRLY
QUICK TRANSITION TO A LINEAR STRUCTURED MCS. THE EXCEPTION MAY BE ON
THE SRN END OF THE LINE FROM NORTHWEST SWD INTO WCNTRL TX WHERE MORE
DISCRETE CONVECTION MAY PERSIST INTO THE EARLY EVENING. THIS SHOULD
RESULT IN A LONGER-LIVED SUPERCELL THREAT FROM FAR SW OK SWD TO
AROUND SAN ANGELO WITH SEVERAL TORNADOES AND POSSIBLY LARGE HAIL
GREATER THAN 2 INCHES IN DIAMETER WHERE A HATCHED AREA FOR
SIGNIFICANT HAIL HAS BEEN ADDED. A STRONG TORNADO ALSO CAN NOT BE
RULED OUT. ALTHOUGH LARGE HAIL AND AN ISOLATED TORNADO THREAT MAY
ALSO EXIST FURTHER NORTH INTO CNTRL OK...THE MORE PREDOMINANT THREAT
COULD BECOME WIND DAMAGE AS A SQUALL-LINE MOVES EWD INTO ECNTRL OK
AND ACROSS NORTH TX DURING THE EARLY EVENING.
..BROYLES.. 11/06/2011
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