Monday, April 23, 2007

DAY1SVR: Day 1 Convective Outlook

ACUS01 KWNS 231631
SWODY1
SPC AC 231629

DAY 1 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
1129 AM CDT MON APR 23 2007

VALID 231630Z - 241200Z

..THERE IS A MDT RISK OF SVR TSTMS OVER PARTS OF E CO...WRN KS AND
THE OK/TX PANHANDLES...

..THERE IS A SLGT RISK OF SVR TSTMS OVER REMAINING PARTS OF THE
CNTRL AND SRN PLNS...

..SYNOPSIS...
SRN GRT BASIN UPR LOW SHOULD CONTINUE SLOWLY E TOWARD THE FOUR
CORNERS REGION TODAY...REACHING N CNTRL NM EARLY TUESDAY AS HEIGHTS
SLIGHTLY REBOUND OVER THE SRN/CNTRL PLNS. SUBTROPICAL IMPULSE NOW
CROSSING THE GULF OF CA SHOULD ACCELERATE NEWD IN TIGHTENING
GRADIENT ON SIDE OF GRT BASIN LOW. IN THE EAST...SYSTEM THAT
CROSSED THE PLAINS OVER THE WEEKEND WILL CONTINUE TO BECOME ABSORBED
IN FAST NRN STREAM FLOW OVER THE LWR GRT LKS.

AT THE SFC...LEE LOW LIKELY TO DEEPEN OVER NE NM TODAY BEFORE
TURNING NE INTO SE CO EARLY TUESDAY. COLD FRONT AND PREFRONTAL
TROUGH ASSOCIATED WITH GRT LKS SYSTEM WILL SETTLE SLOWLY S INTO THE
OH VLY.

..CO FRONT RANGE AND ADJACENT HI PLNS...
PATTERN STILL APPEARS FAVORABLE FOR THE DEVELOPMENT OF DENVER
CYCLONE N OF THE PALMER DIVIDE TODAY. COMBINATION OF SFC HEATING
WITH STEEP LOW TO MID LEVEL LAPSE RATES AND ADVECTION OF MID 40S SFC
DEWPOINTS W TO THE FRONT RANGE WILL BOOST MLCAPE TO AROUND 1000
J/KG. COUPLED WITH UPSLOPE FLOW AND VEERING WIND PROFILES...SETUP
WILL SUPPORT SUSTAINED STORMS/SUPERCELLS BY MID TO LATE AFTERNOON
OVER N CNTRL/NE CO. ALONG WITH LARGE HAIL... ENHANCED LOW LEVEL
DIRECTIONAL SHEAR N OF THE DENVER CYCLONE MAY PROMOTE DEVELOPMENT OF
A FEW TORNADOES.

IN CONTRAST TO MOST ERN CO SVR WX SITUATIONS...CONDITIONS EXPECTED
TO BECOME FAVORABLE FOR MORE WIDESPREAD SVR ACTIVITY OVER THE CO
PLNS LATER THIS EVENING. INFLUX OF RICHER BOUNDARY LAYER MOISTURE
FROM KS /DEWPOINTS IN THE 50S/...COUPLED WITH STRENGTHENING
SHEAR/LARGE SCALE ASCENT IN EXIT REGION OF JET STREAK WITH GRT BASIN
TROUGH...EXPECTED TO SUPPORT INTENSIFICATION OF EXISTING STORMS
AND/OR DEVELOPMENT OF NEW ACTIVITY IN E CNTRL/NE CO. THESE STORMS
MAY EXTEND A THREAT FOR LARGE HAIL...HIGH WIND AND A COUPLE
TORNADOES INTO EARLY TUESDAY.

..CNTRL/SRN PLNS...
A CONDITIONAL THREAT FOR SUPERCELLS WILL EXIST THIS AFTERNOON AND
EARLY TONIGHT IN INCREASINGLY UNSTABLE ENVIRONMENT ALONG DRY LINE
FROM THE TX PANHANDLE NNW INTO SW KS AND PERHAPS FAR ERN CO. STORMS
MAY ALSO FORM BY SUNSET IN ZONE OF STRENGTHENING ASCENT ALONG
DEVELOPING WARM FRONT IN SW/S CNTRL KS. AMPLE SHEAR/CAPE
WILL BE PRESENT FOR SUPERCELLS...ESPECIALLY IN THE PANHANDLES REGION
WHERE ASCENT MAY BE ENHANCED BY APPROACH OF BAJA DISTURBANCE.
MOISTURE WILL BE QUITE RICH AND DEEP MIXING SHOULD BE LIMITED OVER
MUCH OF THE AREA BY HIGH CLOUDS. THUS...POTENTIAL WILL EXIST FOR
TORNADOES IN ADDITION TO LARGE HAIL.

..OH VLY/LWR GRT LKS...
DEEP...LARGELY UNIDIRECTIONAL WLY WIND FIELD /WITH 40-50 KT 0-6 KM
SHEAR/ ON SRN FRINGE OF EJECTING UPR TROUGH WILL BE FAVORABLE FOR
SVR STORMS IN WARM SECTOR OVER THE OH VLY/LWR GRT LKS TODAY. BUT
PLUME OF WARM MID LEVEL AIR AND MODEST LOW LEVEL MOISTURE
AVAILABILITY WILL STRONGLY LIMIT SFC-BASED INSTABILITY. CAPPING AND
LIMITED CONVERGENCE SHOULD PROHIBIT STORM DEVELOPMENT THROUGH MOST
OF THE DAY. CONVERGENCE WILL..HOWEVER...DEEPEN OVER THE REGION BY
EARLY EVENING AS COLD FRONT OVERTAKES PREFRONTAL TROUGH. THIS MAY
SUPPORT DEVELOPMENT OF A BAND OF STORMS FROM WRN NY/PA WSW INTO SRN
IND/IL. RELATIVELY STEEP LOW LEVEL LAPSE RATES AND MODERATE WIND
FIELD MAY YIELD STRONG WIND GUSTS/MARGINAL HAIL IN A FEW STORMS.

.CORFIDI/CROSBIE.. 04/23/2007

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