SWODY3
SPC AC 050730
DAY 3 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
0230 AM CDT WED OCT 05 2011
VALID 071200Z - 081200Z
...THERE IS A SLGT RISK OF SVR TSTMS FROM SERN SD TO THE TX
PANHANDLE...
...SYNOPSIS...
THE ELONGATED UPPER-LEVEL TROUGH OVER THE WRN CONUS WILL EVOLVE INTO
TWO DISTINCT SHORT WAVE TROUGHS ON FRI. THE MORE VIGOROUS IMPULSE
WILL MOVE N/NEWD ACROSS THE NRN PLAINS INTO S-CNTRL CANADA...WHILE
THE SECONDARY IMPULSE SHOULD SLOWLY SHIFT EWD ACROSS THE
SOUTHWEST/FOUR CORNERS. PRIMARY SURFACE CYCLONE ALONG THE MT/DAKOTAS
BORDER ON FRI MORNING WILL TRACK N/NEWD INTO MANITOBA BY EVENING.
ATTENDANT COLD FRONT WILL PUSH EWD ACROSS THE DAKOTAS INTO WRN
MN...WHILE TRAILING PORTION BECOMES QUASI-STATIONARY ACROSS THE
CNTRL PLAINS INTO WRN TX.
...CNTRL PLAINS TO WRN TX...
A CONTINUED FETCH OF STRONG SLY LOW-LEVEL FLOW WILL FURTHER INCREASE
BOUNDARY LAYER MOISTURE RELATIVE TO D2 AND SHOULD LEAD TO 50S TO
LOWER 60S SURFACE DEW POINTS BECOMING ESTABLISHED AHEAD OF A PACIFIC
COLD FRONT THAT IS EXPECTED TO STALL FROM SERN SD INTO THE TX
PANHANDLE ON FRI AFTERNOON. IN CONJUNCTION WITH DIURNAL
HEATING...THIS SHOULD LEAD TO MODEST INSTABILITY WITH MLCAPE LARGELY
RANGING FROM 500 TO 1500 J/KG. CONVERGENCE ALONG THE FRONT SHOULD
SUPPORT AT LEAST SCATTERED TSTMS FORMING IN THE LATE AFTERNOON. WITH
50-65 KT SWLYS AT 500 MB OVERSPREADING THE FRONTAL AXIS...DEEP-LAYER
SHEAR WILL BE FAVORABLE FOR INITIAL SUPERCELLS. HOWEVER...WITH MEAN
FLOW LARGELY PARALLEL TO THE INITIATING BOUNDARY...TSTMS COULD
QUICKLY GROW UPSCALE INTO CLUSTERS PRIMARILY PRODUCING ISOLATED
SEVERE HAIL/WIND.
TSTM COVERAGE SHOULD INCREASE DURING THE EVENING/OVERNIGHT ACROSS
PARTS OF WRN/CNTRL KS INTO WRN TX AS THE LLJ NOCTURNALLY
STRENGTHENS...AND THE FOUR CORNERS SHORT WAVE TROUGH GRADUALLY
APPROACHES. THIS MAY RESULT IN A MARGINAL SEVERE THREAT LINGERING
INTO FRI NIGHT.
...RED RIVER VALLEY OF ND/MN...
AS THE VIGOROUS SHORT WAVE TROUGH SHIFTS NEWD ACROSS THE WRN
DAKOTAS...AN ATTENDANT BELT OF INTENSE 700-500 MB S/SWLYS SHOULD
BECOME CENTERED OVER THE ERN DAKOTAS INTO WRN MN. THIS WILL RESULT
IN VERY FAVORABLE DEEP-LAYER SHEAR PROFILES ON FRI AFTERNOON AHEAD
OF AN APPROACHING COLD FRONT. NEVERTHELESS...CONSENSUS OF GUIDANCE
SUGGESTS MID-LEVEL LAPSE RATES WILL REMAIN POOR AND WITH RELATIVELY
MEAGER BOUNDARY LAYER MOISTURE...MAY ONLY RESULT IN MINIMAL
INSTABILITY FOR DEEP CONVECTION. GIVEN THIS...WILL HOLD OFF ON A
SLIGHT RISK DELINEATION ATTM.
..GRAMS/KERR.. 10/05/2011
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