SPC AC 301955
DAY 1 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
0155 PM CST THU NOV 30 2006
VALID 302000Z - 011200Z
...THERE IS A SLGT RISK OF SVR TSTMS ACROSS PORTIONS OF THE LWR MS
VLY INTO THE MID-SOUTH AND LWR OH VLY...
...LWR MS AND TN VLYS...
19Z SFC ANALYSIS PLACES 1007 MB LOW VCNTY KHOT WITH A COLD FRONT SWD
INTO NWRN LA AND ANOTHER FRONT NEWD INTO THE KMEM VCNTY TO THE OH
VLY.
THE LOW SHOULD BEGIN TO INTENSIFY RAPIDLY THIS AFTN AS THE PRIMARY
UPPER LOW APPROACHES WRN OK...WITH A TRACK NEWD TO KMEM BY 06Z AND
INTO WRN IND BY 12Z. THE COLD FRONT SHOULD CONTINUE SWEEPING EWD
THROUGH THE LWR MS VLY WHILE THE FRONT IN THE OH VLY RETREATS NWWD.
DEVELOPMENT OF A LOW-TOPPED QUASI-LINEAR CONVECTIVE SYSTEM (QLCS)
APPEARS IMMINENT VCNTY THE COLD FRONT FROM CNTRL AR SWD INTO NRN LA
EARLY THIS AFTN. AHEAD OF THE FRONT...18Z RAOBS AND SELECTED ACARS
SOUNDINGS SUGGEST THAT LAPSE RATES ARE MARGINAL GIVEN THE WARM LAYER
ALOFT. BUT...VSBL SATL SHOWS MODEST INSOLATION OCCURRING THROUGH
THE LWR MS VLY INTO THE MID-SOUTH. THIS WILL TEND TO DESTABILIZE
THE BOUNDARY LAYER AND LESSEN THE INHIBITION SUFFICIENTLY TO SUPPORT
MLCAPES TO AROUND 500 J/KG. THUS...COMBINATION OF STRONG LARGE
SCALE ASCENT AND MARGINAL BUOYANCY WILL LIKELY CONTRIBUTE TO
INCREASING INTENSITY TO THE QLCS LATE AFTN INTO THE EVE FROM
SERN/ECNTRL AR AND NERN LA NEWD INTO THE MID-SOUTH AND LWR OH VLY.
PRE-FRONTAL LOW-LEVEL SHEAR PROFILES ARE NOT PARTICULARLY STRONG
PRIMARILY DUE TO THE LACK OF DIRECTIONAL SHEAR ABOVE THE SFC. THIS
MAY CHANGE DURING THE NEXT SEVERAL HOURS...ESPECIALLY VCNTY THE SFC
LOW TRACK. THUS...IT APPEARS THAT DAMAGING WINDS WILL BE THE
PRIMARY SEVERE THREAT...THOUGH ISOLD TORNADOES WILL REMAIN
POSSIBLE...MAINLY ACROSS ECNTRL/SERN AR INTO NWRN MS AND WRN TN.
THE INCREASING MID-LEVEL FLOW /100+ KTS AT H5/ WILL ENHANCE THE
VERTICAL SHEAR...AND IF A SUFFICIENTLY STRONG UPDRAFT CAN
EVOLVE...EMBEDDED SUPERCELL STRUCTURES WILL BE POSSIBLE. MORE
LIKELY SCENARIO WILL BE FOR BOW ECHO/LEWPS ALONG THE QLCS THAT
PRODUCE CORRIDORS OF DAMAGING WINDS.
..RACY.. 11/30/2006
CLICK TO GET WUUS01 PTSDY1 PRODUCT
NOTE: THE NEXT DAY 1 OUTLOOK IS SCHEDULED BY 0100Z
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