SPC AC 080558
DAY 2 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
1258 AM CDT MON JUN 08 2009
VALID 091200Z - 101200Z
...THERE IS A SLGT RISK OF SVR TSTMS ACROSS A LARGE PORTION OF THE
CNTRL/SRN PLNS TO THE MID-SOUTH...
...THERE IS A SLGT RISK OF SVR TSTMS ACROSS THE MID-ATLC REGION...
...SYNOPSIS...
THE MID-LVL SHORTWAVE TROUGH CURRENTLY MOVING ACROSS THE CNTRL PLNS
IS EXPECTED TO PHASE WITH THE NRN STREAM AND TRANSLATE ACROSS THE
CNTRL APLCNS...GRTLKS AND NY STATE ON TUESDAY. UPSTREAM...RESIDENT
UPR TROUGH RESTRENGTHENING OFF THE CA CST WILL BEGIN TO BODILY EJECT
NEWD TOWARD THE DESERT SW/GRT BASIN TUESDAY AFTN...THEN INTO THE SRN
ROCKIES BY 12Z WED. WEAK IMPULSES WILL LIKELY PRECEDE THIS WAVE
ACROSS THE CNTRL/SRN PLNS. IN THE LWR LVLS...A CDFNT ASSOCD WITH
THE ERN STATES TROUGH WILL CONTINUE TO SETTLE SEWD INTO NY AND THE
CNTRL APLCNS. TAIL-END OF THE FRONT WILL STALL OVER THE
MID-SOUTH...SRN OZARK PLATEAU AND SRN PLNS BEFORE RETURNING NWD
AGAIN AS A WRMFNT TUESDAY EVE.
...CNTRL PLNS TO MID-SOUTH...
A SEASONABLY STRONG CDFNT CURRENTLY MOVG SWD THRU THE PLNS SHOULD
HAVE NO DIFFICULTY MOVING INTO THE MID-SOUTH AND OK BY EARLY
TUESDAY. RELIED HEAVILY ON THE 00Z NAM THIS FCST CYCLE WITH
ANTICIPATION THAT IT HAS A BETTER HANDLE ON FRONTAL PLACEMENT.
RAPIDLY DEVELOPING RETURN FLOW WILL PROBABLY RESULT IN ELEVATED
CONVECTION LATE TONIGHT THROUGH MOST OF TUESDAY MORNING FROM
SRN/CNTRL KS SEWD INTO ERN OK...SRN MO AND AR. THIS WILL LIKELY
REINFORCE THE FRONT...LENDING INCREASED CONFIDENCE THAT THE FRONT
WILL NOT RETURN AS QUICKLY NWD AS THE GFS/ECMWF MODELS SUGGEST.
CAP SHOULD REBUILD ACROSS THE WARM SECTOR WHERE SFC DEW POINTS WILL
BE IN THE MID-UPR 60S...RESULTING IN A POTENTIALLY VERY UNSTABLE AIR
MASS FROM PARTS OF SWRN/SCNTRL KS INTO CNTRL/ERN OK BY LATE AFTN.
WEAK SELY UPSLOPE FLOW...SUSTAINED FRONTAL CONVERGENCE/MOIST INFLOW
WILL LIKELY BE IMPETUS FOR BREACHING THE CAP WITH SCTD SFC-BASED
TSTMS DEVELOPING ALONG THE NE PERIPHERY OF STRONGER HEATING FROM
SWRN/SCNTRL KS INTO NRN/CNTRL OK BY LATE AFTN. WLY H5 FLOW AOA 40
KTS ATOP SELY LLVL FLOW WILL CREATE SUFFICIENT SHEAR FOR SUPERCELLS
WITH LARGE HAIL...DMGG WINDS AND POSSIBLY TORNADOES.
A STG SSWLY LLJ IS PROGD TO DEVELOP TUESDAY NIGHT...RESULTING IN AN
EXTENSIVE ZONE OF WARM/MOIST ADVECTION NE OF THE FRONT. THIS SHOULD
SUPPORT SEVERAL NOCTURNAL TSTM CLUSTERS...EVOLVING FROM BOTH HIGH
PLNS STORMS IN SWRN NEB/NWRN KS/ERN CO AND FROM ACTIVITY ACROSS
CNTRL/ERN KS AND MO. SOME STORMS MAY CONTAIN LARGE HAIL...WITH
PERHAPS A DMGG WIND THREAT ALONG SRN EDGES OF THE MCS/S. SVR
THREATS MAY CONTINUE DOWNSTREAM...REACHING THE MID-SOUTH BY EARLY
WEDNESDAY.
LATER OTLKS WILL NEED TO ADDRESS THE POTENTIAL FOR HIGHER SVR
PROBABILITIES...ONCE FRONTAL PLACEMENT IS BETTER RESOLVED.
...MID-ATLC REGION...
INCREASING WAA/MOIST ADVECTION AND WEAK DCVA WILL LIKELY DRIVE
CONSIDERABLE SHWRS/TSTMS EARLY TUESDAY OVER ERN PA...NJ NWD INTO NY.
WARM SECTOR SHOULD HAVE NO PROBLEM SPREADING NWD AS FAR N AS SERN
PA/DE IN WAKE OF EARLY DAY PCPN. VERY MOIST BOUNDARY LAYER AND
STRONG HEATING ALONG/E OF THE LEE TROUGH SHOULD CONTRIBUTE TO
MLCAPES 2000+ J/KG WITH MINIMAL CINH. TSTMS WILL LIKELY DEVELOP
EAST OF THE BLUE RIDGE AND EVOLVE INTO MULTI-CELL CLUSTERS/LINES
WITH DMGG WINDS AND HAIL AS THEY MOVE TOWARD THE CST BY LATE AFTN.
SLGT RISK COULD BE EXPANDED N IN LATER OTLKS...ONCE QUESTIONS
REVOLVING AROUND EARLY DAY CLDS/PCPN AND THEIR POTENTIAL EFFECTS ON
DESTABILIZATION ARE BETTER UNDERSTOOD.
...WRN NY STATE SWWD TO THE MID-OH VLY...
AIR MASS DESTABILIZATION WILL HINGE ON HOW RAPIDLY WAA DERIVED
PCPN/CLOUDS CAN DEPART AWAY FROM THE CDFNT TUESDAY AFTN.
EXPECTATION IS THAT MODEST BUOYANCY WILL DEVELOP WITH WDLY SCTD
TSTMS FORMING BY EARLY AFTN. ISOLD STORMS MAY CONTAIN HIGH
WINDS/HAIL.
..RACY.. 06/08/2009
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