DAY1SVR: Day 1 Convective Outlook

ACUS01 KWNS 091632
SWODY1
SPC AC 091630

DAY 1 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
1030 AM CST SAT MAR 09 2013

VALID 091630Z - 101200Z

...THERE IS A SLGT RISK OF SVR TSTMS PORTIONS TX/OK/WESTERN AR...

...THERE IS A SLGT RISK OF SVR TSTMS PORTIONS CENTRAL/SRN NEB AND
EXTREME NRN KS...

...SYNOPSIS...
PRIMARY UPPER-AIR FEATURE FOR THIS PERIOD WILL BE
ELONGATED/CONTORTED REGIME OF TROUGHING FROM CENTRAL CANADA ACROSS
CENTRAL/SERN CONUS. WITHIN THAT...MID-UPPER LEVEL CYCLONE IS
CENTERED INITIALLY OVER 4-CORNERS AREA. THIS FEATURE IS EXPECTED TO
SHIFT EWD TO ENEWD ACROSS CO/NM BORDER AREA TODAY...REACHING SRN KS
BY END OF PERIOD. POSITIVELY TILTED TROUGH WILL TRAIL SWWD ACROSS
SRN HIGH PLAINS TO SONORAN DESERT.

AT SFC...15Z CHART DEPICTED PRIMARY LOW STILL ANCHORED INVOF SRN
PORTIONS KS/CO BORDER...SECONDARY LOW OVER CENTRAL NEB...AND COLD
FRONT CONNECTING THEM. PAC COLD FRONT ARCHED SEWD FROM MAIN LOW
ACROSS ERN PORTIONS TX PANHANDLE...THEN SSWWD OVER W TX TO BIG
BEND/NWRN COAHUILA REGION. BY 00Z...MAIN LOW SHOULD EJECT NEWD
ACROSS SWRN/W-CENTRAL KS...REACHING RSL AREA...WITH FRONT OVER WRN
OK AND NW/W-CENTRAL TX. BY 12Z...EXPECT LOW INVOF EXTREME E-CENTRAL
KS...AND COLD FRONT OVER WRN AR...NE TX...AND DEEP S TX.

PRIMARY UPDATE TO FCST IS TO BOOST PROBABILITIES OVER CENTRAL-PLAINS
AREA AS DESCRIBED BELOW.

...KS/NEB...
VIS IMAGERY ALREADY INDICATES MERIDIONAL CORRIDOR OF CLEARING
ASSOCIATED WITH SWATH OF MID-UPPER DRYING EVIDENT IN MOISTURE
CHANNEL IMAGERY FROM TX PANHANDLE ACROSS WRN KS TO PORTIONS
SWRN/S-CENTRAL NEB. FCST SOUNDINGS SUGGEST TEMPS ONLY NEAR 60 F
WILL BE NEEDED TO ATTAIN SFC-BASED EFFECTIVE INFLOW PARCELS...AMIDST
FAVORABLE DEEP-LAYER WIND PROFILES AND LOW-LEVEL SHEAR REGIME FCST
NEAR SECONDARY SFC LOW/TRIPLE POINT. CONTINUED MOIST ADVECTION AND
INSOLATION AHEAD OF COLD FRONT SHOULD RESULT IN NARROW PLUME OF
MLCAPE 500-1000 J/KG OVER THIS REGION BY MID-AFTN. LOW LEVEL
SRH/VORTICITY SHOULD REMAIN MAXIMIZED IN SMALL AREA OF S-CENTRAL NEB
AND PERHAPS EXTREME N-CENTRAL KS...SUPPORTING POTENTIAL FOR SMALL
SUPERCELLS AND RISK OF A FEW BRIEF TORNADOES. STG-ISOLATED SVR
GUSTS AND OCNL HAIL NEAR SVR LEVELS ALSO IS POSSIBLE.

...TX/OK/WESTERN AR...
NO SUBSTANTIAL ADJUSTMENTS ARE WARRANTED TO EITHER REASONING OR
SPATIAL AREAS FROM PREV OUTLOOK. BAND OF TSTMS IS EXPECTED TO
DEVELOP INVOF PROGRESSIVE PAC FRONT THIS AFTN AND MOVE INTO
INCREASINGLY MOIST LOW-LEVEL AIR MASS. SFC DEW POINTS UPPER 50S TO
LOW-60S F WILL OFFSET WEAK LAPSE RATES ALOFT JUST ENOUGH TO
CONTRIBUTE TO 500-1000 J/KG MLCAPE...AMIDST 45-55 KT EFFECTIVE SHEAR
MAGNITUDES. MOST FAVORABLE JUXTAPOSITION OF CAPE/SHEAR PARAMETER
SPACE FOR SUPERCELLS STILL APPEARS TO BE LATE AFTN/EVENING OVER
PORTIONS OF SRN OK AND N TX...RELATIVELY MAXIMIZING PROBABILITIES
FOR HAIL/TORNADOES IN THAT AREA.

..EDWARDS/GARNER.. 03/09/2013

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