SPC AC 310753
DAY 2 CONVECTIVE OUTLOOK CORR 2
NWS STORM PREDICTION CENTER NORMAN OK
0253 AM CDT THU MAY 31 2007
VALID 011200Z - 021200Z
...THERE IS A SLGT RISK OF SVR TSTMS FROM PARTS OF THE SRN AND CNTRL
PLAINS INTO THE MID MS VALLEY REGION...
CORRECTED FOR GENERAL THUNDER GRAPHIC LINES
...SYNOPSIS...
UPPER LOW OVER THE NORTH CNTRL STATES WILL MOVE VERY SLOWLY EWD
FRIDAY. VORT MAX NOW ROTATING WWD INTO ERN MT ALONG NWRN PERIPHERY
OF UPPER LOW WILL DROP SWD THEN EWD INTO BASE OF THE UPPER LOW
REACHING THE CNTRL PLAINS BY FRIDAY. FRONTAL BOUNDARY WILL EXTEND
FROM THE UPPER MS VALLEY OR NRN PLAINS SWD THROUGH WRN KS AND SERN
CO EARLY FRIDAY. LEE TROUGH/DRYLINE WILL EXTEND FROM WRN TX NWD INTO
SWRN KS. MODELS SUGGEST SURFACE LOW WILL DEVELOP ALONG KS PORTION OF
FRONT AND LIFT NEWD INTO THE MID MS VALLEY DURING THE DAY IN
RESPONSE TO INCREASING ASCENT ATTENDING VORT MAX ROTATING THROUGH
BASE OF UPPER TROUGH. AS LOW LIFTS NE...TRAILING PORTIONS OF FRONT
WILL SHIFT SWD INTO THE SRN PLAINS DURING THE AFTERNOON.
UPPER TROUGH NOW MOVING INTO SRN CA IS FORECAST TO MOVE INTO WRN TX
DURING THE DAY.
UPPER LOW OVER THE NRN GULF WILL DRIFT EWD AND MAY APPROACH THE FL
PENINSULA BY LATE FRIDAY.
...ERN KS THROUGH MID MS VALLEY...
FORECAST IS SOMEWHAT COMPLICATED AND UNCERTAINTIES EXIST DUE TO
LIKELIHOOD OF ONGOING STORMS AT BEGINNING OF PERIOD. MCS MAY BE IN
PROGRESS OVER PARTS OF CNTRL OR ERN KS SWD INTO OK WITHIN
PRE-FRONTAL WARM SECTOR. AXIS OF 60S DEWPOINTS WILL LIKELY EXIST IN
WARM SECTOR...BUT DESTABILIZATION POTENTIAL WILL DEPEND ON EXTENT OF
CLOUDS WHICH WILL BE MOST WIDESPREAD IN VICINITY OF THE MCS. BELIEVE
BEST POTENTIAL FOR HEATING WILL BE FARTHER EAST TOWARD THE MID MS
VALLEY WITH MLCAPE FROM 1000 TO 1500 J/KG POSSIBLE. DESPITE
POTENTIAL THERMODYNAMIC LIMITING FACTORS...THE KINEMATIC ENVIRONMENT
SHOULD REMAIN SUFFICIENT FOR ORGANIZED STORM STRUCTURES. LOW LEVEL
JET WILL LIKELY SHIFT NEWD ALONG WITH SURFACE LOW THROUGH ERN KS AND
INTO THE MID MS VALLEY WITHIN ZONE OF ASCENT ATTENDING EWD ADVANCING
VORT MAX ROTATING THROUGH BASE OF UPPER TROUGH. LOW LEVEL HODOGRAPHS
AND DEEP LAYER SHEAR WILL SUPPORT POTENTIAL FOR SUPERCELLS WITH LOW
LEVEL MESOCYCLONES AS STORMS ADVANCE EAST AND THE ATMOSPHERE
DESTABILIZES. PRIMARY UNCERTAINTY AT THIS TIME WILL BE STORM MODE
GIVEN POTENTIAL FOR THE MCS TO CONTINUE EWD...BUT ADDITIONAL STORMS
MAY ALSO DEVELOP IN ADVANCE OF THIS FEATURE. LARGE HAIL...DAMAGING
WIND AND ISOLATED TORNADOES WILL BE THE PRIMARY THREATS.
...SRN PLAINS...
SOME POTENTIAL FOR ONGOING SEVERE WEATHER MAY PERSIST INTO EARLY
FRIDAY WITH ANY STORMS OR MCS ACROSS OK. HOWEVER...THE STRONGER
DEEPER LAYER FORCING AND STRONGER LOW LEVEL AND UPPER LEVEL WIND
FIELDS WILL LIKELY REMAIN N OF THIS REGION. SOME POTENTIAL WILL
EXIST FOR THE ATMOSPHERE DOWNSTREAM FROM THE MCS TO
DESTABILIZE...AND AT LEAST MODEST SLY LOW LEVEL INFLOW COULD SUSTAIN
THE MCS INTO THE AFTERNOON. DEPENDING ON HOW WIDESPREAD CLOUDS AND
STABILIZING EFFECTS FROM ONGOING CONVECTION ARE...SOME
DESTABILIZATION MAY ALSO OCCUR IN WAKE OF THIS FEATURE AND
ADDITIONAL STORMS MAY DEVELOP UPSTREAM ALONG THE FRONT AND SPREAD
SEWD THROUGH SRN KS AND INTO OK. THREAT IN THIS REGION APPEARS MORE
CONDITIONAL...BUT IF SUFFICIENT DESTABILIZATION CAN OCCUR THREAT
WILL EXIST FOR MAINLY ISOLATED DAMAGING WIND AND HAIL.
...SRN HIGH PLAINS OF ERN NM AND WRN TX...
PROXIMITY TO STEEPER LAPSE RATES AND POTENTIAL FOR STRONG SURFACE
HEATING WILL LIKELY RESULT IN MODERATE INSTABILITY IN PRE-FRONTAL
WARM SECTOR OVER WRN TX. SOME ELY UPSLOPE COMPONENT MAY DEVELOP IN
POST FRONTAL REGION AND ADVECT HIGHER DEWPOINTS WWD INTO PARTS OF
NERN NM DURING THE AFTERNOON. STORMS MAY DEVELOP ALONG THE SWD
ADVANCING FRONT OVER PARTS OF NWRN TX AND IN UPSLOPE REGION OF NM
AND SPREAD SEWD DURING THE AFTERNOON. MORE ISOLATED DEVELOPMENT WILL
BE POSSIBLE FARTHER S ACROSS WRN TX. UPPER FLOW WILL BE MUCH WEAKER
IN THIS REGION THAN FARTHER NE. AN EXCEPTION MAY BE OVER SWRN TX
WHERE A BELT OF STRONGER UPPER FLOW MAY ACCOMPANY THE SRN STREAM
SHORTWAVE TROUGH. DESPITE THE MODEST MID LEVEL FLOW...DIRECTIONAL
SHEAR MAY BECOME AT LEAST MARGINALLY SUFFICIENT FOR SUPERCELL
STRUCTURES. PRIMARY THREATS WILL BE ISOLATED DAMAGING WIND AND HAIL.
...FL...
DEPENDING ON HOW FAR EAST UPPER LOW OVER NRN GULF PROGRESSES...
HODOGRAPHS MAY BECOME INCREASINGLY SUPPORTIVE OF SUPERCELL
STRUCTURES. HOWEVER... THE WEAK MID LEVEL LAPSE RATES AND POTENTIAL
FOR WIDESPREAD CLOUDS WILL LIKELY LIMIT INSTABILITY IN THIS REGION.
WILL INTRODUCE 5% SEVERE PROBABILITIES AT THIS TIME...BUT CONTINUE
TO MONITOR FOR POSSIBLE HIGHER PROBABILITIES IN LATER OUTLOOKS.
..DIAL.. 05/31/2007
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