SWODY3
SPC AC 290729
DAY 3 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
0229 AM CDT TUE APR 29 2008
VALID 011200Z - 021200Z
...THERE IS A SLGT RISK OF SVR TSTMS ERN NEB/WRN IA SSWWD TO
PORTIONS N-CENTRAL/NE TX...
...SYNOPSIS...
BROAD MID/UPPER CYCLONE NOW OFFSHORE PACIFIC NW AND BC WILL SHIFT
ESEWD ACROSS PACIFIC NW AND OVER MUCH OF CENTRAL/NRN ROCKIES BY
1/12Z. LEAD SHORTWAVE TROUGH NOW OFFSHORE ORE SHOULD EJECT NWD
ACROSS MT DAY-2 AND REINFORCE/MERGE WITH CYCLONE CORE OVER SRN AB BY
START OF THIS PERIOD. MEANWHILE...VORTICITY LOBE -- NOW EVIDENT IN
MOISTURE CHANNEL IMAGERY OVER GULF OF AK...IS FCST TO REVOLVE SWD
THEN SEWD AROUND UPPER CYCLONE AND AMPLIFY CONSIDERABLY...REACHING
CENTRAL ROCKIES OR CENTRAL HIGH PLAINS BY 2/00Z. MODEL
INCONSISTENCIES DESCRIBED IN DAY-2 OUTLOOK WITH THIS SHORTWAVE
TROUGH...AND WITH LOCATION OF ASSOCIATED SFC CYCLONE ALONG COLD
FRONT...EXTEND INTO DAY-3 PERIOD...AND WILL AFFECT LOCATION/STRENGTH
OF GREATEST SVR POTENTIAL.
PRIND SFC LOW SHOULD LIFT NEWD ACROSS CENTRAL/N-CENTRAL KS EARLY IN
PERIOD AND BE LOCATED SOMEWHERE OVER ERN NEB BY 2/00Z...WITH COLD
FRONT TRAILING SWWD ACROSS S-CENTRAL/SERN KS...N-CENTRAL THROUGH
W-CENTRAL/SW OK AND TX PANHANDLE. DRYLINE SHOULD INTERSECT FRONT
INVOF N-CENTRAL OK AND EXTEND SSWWD ACROSS PARTS OF CENTRAL/SRN OK
AND N-CENTRAL/NW TX. COLD FRONT SHOULD OVERTAKE DRYLINE OVERNIGHT
AND MOVE EWD INTO MO...AND SEWD ACROSS ERN OK AND WRN/NRN TX.
...CENTRAL/SRN PLAINS...LOWER MO VALLEY...
SOMEWHAT TIGHTLY CLUSTERED SVR OUTBREAK IS POSSIBLE -- INCLUDING
SUPERCELLS WITH LARGE/DAMAGING HAIL AND POSSIBLY SIGNIFICANT
TORNADOES. ATTM...CONSENSUS OF SREF AND OPERATIONAL PROGS INDICATES
PORTIONS ERN KS...NERN OK...AND WRN MO MAY HAVE MAXIMUM OVERALL
POTENTIAL. HOWEVER...NON-TRIVIAL THREAT EXTENDS NWD TOWARD SERN
NEB/SRN IA/NRN MO AND SWD OVER ERN OK/NWRN AR. UNCERTAINTIES
PRECLUDING GREATER PROBABILITIES ATTM INVOLVE TRACK/INTENSITY OF SFC
LOW AND RELATED LOW LEVEL FORCING...NWD EXTENT OF MOST FAVORABLE
RETURN FLOW MOISTURE...AND CAPPING ALONG/AHEAD OF DRYLINE OVER ERN
OK AND RED RIVER REGION. AS SOME OF THESE MESOSCALE DETAILS BECOME
BETTER RESOLVED...CATEGORICAL RISK UPGRADE IS POSSIBLE FOR THIS FCST
PERIOD.
STRONGER DEEP-LAYER FORCING IS FCST TO LIFT NEWD ACROSS LOWER MO
VALLEY REGION DURING DAY...WITH EARLIER INITIATION OF STG-SVR TSTMS
LIKELY THAN FARTHER S WHERE SBCINH WILL BE STRONGER AND LOW LEVEL
CONVERGENCE SOMEWHAT WEAKER. NRN PORTION OUTLOOK INCLUDES
CONDITIONAL POTENTIAL OF RELATIVELY SMALL/LOW-TOPPED SUPERCELLS WITH
TORNADOES AND HAIL JUST NE-E OF SFC LOW. FARTHER S...LARGE
LOW-MIDLEVEL LAPSE RATES...STRONGER CAPPING...GREATER LOW LEVEL
MOISTURE AND STRONGER HEATING WILL CONTRIBUTE TO SOMEWHAT MAXIMIZED
POTENTIAL FOR DISCRETE....WIDELY SCATTERED TO ISOLATED DEVELOPMENT
OF SUPERCELLS WITH POTENTIAL FOR SIGNIFICANT SEVERE OVER ERN OK AND
SERN KS. DEVELOPMENT FARTHER S TOWARD N-CENTRAL TX BECOMES
PROGRESSIVELY MORE CONDITIONAL...ESPECIALLY BEFORE DARK. BAND OF
SVR TSTMS SHOULD EVOLVE BY AROUND 02/06Z FROM MO SWWD ACROSS ERN
OK/ERN AR AND PERHAPS NE TX...WITH THREAT EVOLVING MORE TOWARD
DAMAGING WIND...BUT WITH TORNADOES AND HAIL STILL POSSIBLE.
..EDWARDS.. 04/29/2008
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