SPC AC 230055
DAY 1 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
0755 PM CDT THU APR 22 2010
VALID 230100Z - 231200Z
...THERE IS A MDT RISK OF SVR TSTMS PORTIONS SWRN KS...ERN PANHANDLE
OF TX...NW TX...WRN OK...
...THERE IS A SLGT RISK OF SVR TSTMS ELSEWHERE IN ARC FROM SW TX
ACROSS WRN/CENTRAL OK TO NERN CO...AND SEWD ACROSS MUCH OF
WRN/CENTRAL/SRN KS....
...SYNOPSIS...
SPLIT-FLOW PATTERN ALOFT IS DOMINATED BY LARGE CYCLONIC GYRE
COVERING MUCH OF SWRN CONUS...INTERMOUNTAIN REGION AND NWRN MEX.
SEVERAL SMALLER-SCALE SHORTWAVE TROUGHS ARE ROTATING AROUND THIS
CYCLONE...INCLUDING PERTURBATION NOW EVIDENT OVER SERN AZ. LATTER
FEATURE SHOULD EJECT ACROSS NM OVERNIGHT...MOVING TO ERN CO BY 12Z
AND EVOLVING INTO DEEPEST OF TWO LOWS EMBEDDED IN 500 MB CYCLONE.
TRAILING LOW SHOULD REACH CENTRAL/SRN AZ BY END OF PERIOD.
23Z SFC MAP DEPICTED CYCLONE BETWEEN LHX-LIC...WHICH SHOULD DEEPEN
OVER SERN CO AND MOVE LITTLE THROUGH REMAINDER PERIOD. WARM FRONT
-- NOW EXTENDING ESEWD FROM LOW OVER SRN 1-2 TIERS OF KS COUNTIES --
IS EXPECTED TO LIFT NWD TO NEAR I-70 OVERNIGHT...LOCALLY MODULATED
BY CONVECTIVE/OUTFLOW PROCESSES. COLD FRONT ARCS SEWD FROM LOW
ACROSS TX PANHANDLE E OF AMA -- JUST BEHIND MAIN BAND OF CONVECTION
NOW PRESENT OVER ERN PANHANDLE -- THEN SSWWD NEAR LBB AND ACROSS
SERN NM. DRYLINE -- ANALYZED INITIALLY FROM FRONT NEAR LBB SSWWD
BETWEEN MAF-FST...WILL RETREAT NWWD BEFORE BEING OVERTAKEN FROM N-S
BY FRONT THROUGH REMAINDER PERIOD...AS FRONT PROCEEDS TO 12Z
POSITION NEAR DRT...MWL...CSM...GLD.
...CENTRAL/SRN HIGH PLAINS TO SW TX...CENTRAL OK...CENTRAL KS...
SCATTERED-NUMEROUS STG AND SVR TSTMS -- INCLUDING SEVERAL SUPERCELLS
PRODUCING VERY LARGE/DAMAGING HAIL AND INTERMITTENT TORNADOES -- ARE
PRESENT E OF COLD FRONT/DRYLINE AND NE OF SFC LOW FROM ERN CO TO TX
PANHANDLE...WITH ADDITIONAL DEVELOPMENT OCCURRING SWD TOWARD PERMIAN
BASIN. PRIMARY TORNADO/SIGNIFICANT-SEVERE HAIL RISK IS
ONGOING...REF SPC WWS 74-76 AND RELATED MESOSCALE DISCUSSIONS FOR
LATEST ON NEAR-TERM SVR SITUATION IN AND NEAR THOSE WWS.
AS CONVECTION INCREASES IN COVERAGE THROUGH REMAINDER EVENING FROM
WARM FRONT SWD TO AREA E OF DRYLINE IN W TX...FLOW ALOFT WILL BECOME
MORE MERIDIONAL IN ITS ENVIRONMENT...AS GEOMETRY OF KINEMATIC FIELDS
ALOFT ADJUSTS TO APCHG UPPER VORTEX. THIS ALREADY APPEARS TO BE
CONTRIBUTING TO LINEAR COALESCING OF EARLIER SUPERCELLS IN ERN TX
PANHANDLE...AND WILL SUPPORT MORE UPSCALE COVERAGE OF LINEAR
STRUCTURE TONIGHT. HOWEVER...DEEP-LAYER SHEAR WILL REMAIN QUITE
FAVORABLE FOR SVR...WITH 50-60 KT EFFECTIVE SHEAR MAGNITUDE OVER
BROAD AREA. HODOGRAPHS WILL BE ENLARGED BY STRENGTHENING LLJ FOR
PARCELS THAT WILL REMAIN SFC-BASED OR NEARLY SO FOR SEVERAL MORE
HOURS...DURING GRADUAL INCREASE IN MLCINH. EMBEDDED SUPERCELLS WILL
BE POSSIBLE...AS WELL AS DAMAGING LEWP/BOW ECHOES...ALONG WITH
DISCRETE STORMS AHEAD OF CONVECTIVE BAND AND NEAR ITS SRN END. LATE
THIS EVENING AND OVERNIGHT...OVERALL MAX HAIL SIZES SHOULD
LESSEN...BUT WITH DENSE PRODUCTION OF AT LEAST MRGL SVR HAIL STILL
POSSIBLE...ALONG WITH DAMAGING WIND AND A FEW TORNADOES.
..EDWARDS.. 04/23/2010
CLICK TO GET WUUS01 PTSDY1 PRODUCT
NOTE: THE NEXT DAY 1 OUTLOOK IS SCHEDULED BY 0600Z
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