Thursday, June 10, 2010

DAY1SVR: Day 1 Convective Outlook

ACUS01 KWNS 101631
SWODY1
SPC AC 101629

DAY 1 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
1129 AM CDT THU JUN 10 2010

VALID 101630Z - 111200Z

...THERE IS A MDT RISK OF SVR TSTMS FROM NORTHEAST COLORADO AND
EXTREME SOUTHEAST WYOMING TO NORTHWEST KANSAS AND MUCH OF SOUTHWEST
NEBRASKA INCLUDING THE SOUTHERN PORTION OF THE NEBRASKA PANHANDLE...

...THERE IS A SLGT RISK OF SVR TSTMS SURROUNDING THE SLGT RISK AREA
FROM THE TX PANHANDLE NWD ACROSS THE CENTRAL PLAINS AND MID MISSOURI
RIVER VALLEY...

...CENTRAL HIGH PLAINS...
LATE MORNING SFC ANALYSIS REVEALS AT LEAST THREE LOW CENTERS ACROSS
THE CNTRL HIGH PLAINS EMBEDDED WITHIN LEE/SYNOPTIC-SCALE TROUGHING
FROM WRN SD TO ERN CO. OUTFLOW SURGE IN THE WAKE OF ERN NEB/WRN IA
MCS WAS EVIDENT IN RADAR AND SATELLITE IMAGERY AND EXTENDS ACROSS
NWRN KS TO SERN CO. LOW CLOUDS ARE PERSISTING TO THE NORTH OF THIS
OUTFLOW BOUNDARY...FROM NERN CO ACROSS MUCH OF SRN NEB ATTM. EXPECT
THE INFLUENCE OF THIS WIND SHIFT AND WEAK COLD POOL TO GRADUALLY
DIMINISH THROUGH THE AFTERNOON AS DIURNAL/DIABATIC PROCESSES AND
SYNOPTIC FORCING INCREASE IN DOMINANCE.

DIURNAL HEATING OF VERY MOIST AND CAPPED WARM SECTOR AIRMASS /SFC
DEWPOINTS 65-70F/ WILL CONTRIBUTE THE DEVELOPMENT OF STRONG TO
LOCALLY EXTREME INSTABILITY /MLCAPE TO 3000 J PER KG/ LATER THIS
AFTERNOON FROM WRN KS INTO SRN NEB. MEANWHILE...PERSISTENT HEIGHT
FALLS WITH APPROACH OF WRN U.S. SHORTWAVE TROUGH WILL AID LEE-SIDE
CYCLOGENESIS ACROSS ERN CO. AS LOW LEVEL FLOW RESPONDS TO THIS
DEVELOPMENT...AND RECOVERS IN THE WAKE OF DECAYING OUTFLOW SURGE
ACROSS NERN CO...EXPECT AN INCREASE IN MOISTURE TRANSPORT AND
UPSLOPE FLOW FROM NERN CO ACROSS SERN WY.

SYNOPTIC LIFT AND WEAKER INHIBITION ARE EXPECTED TO PROMOTE STRONG
TO ISOLD SEVERE STORM DEVELOPMENT ACROSS THE MOUNTAINS OF NRN CO AND
ERN WY BY 20-21Z. THIS ACTIVITY WILL OCCUR COINCIDENT WITH 40-50 KT
SW MID LVL FLOW AND EFFECTIVE SHEAR FAVORABLE FOR UPDRAFT
PERSISTENCE AND HAIL PRODUCTION. STORMS SHOULD QUICKLY EVOLVE INTO
SUPERCELLS THAT WILL THEN MOVE/DEVELOP EWD INTO INCREASINGLY
STRONG/MOIST LOW LVL ELY FLOW TO THE N OF CONSOLIDATING LEE-SIDE SFC
LOW.

THROUGH THE EVENING....THE CONTINUATION OF LARGE SCALE SUPPORT FOR
UPWARD MOTION AND SFC INTENSIFICATION OF LOW...DRYLINE AND WARM
FRONT...SHOULD RESULT IN ROBUST STORM DEVELOPMENT AND INCREASE IN
STORM COVERAGE FROM NERN CO INTO ADJACENT AREAS OF NEB/KS THROUGH
THE EVENING. STRENGTH OF CAPPING INVERSION/EML WITH SWD EXTENT
SUGGESTS EITHER A SHARP CUT-OFF TO SEVERE THREAT...OR MORE
ISOLD/DISCRETE STORMS SWD ALONG THE DRYLINE.

MUCH OF THIS ACTIVITY LIKELY WILL PRODUCE VERY LARGE HAIL GIVEN
MAGNITUDE OF INSTABILITY AND SHEAR FORECAST ACROSS THE AREA.
ENHANCED LOW LEVEL DIRECTIONAL SHEAR WILL EXIST NEAR AND NORTH OF
THE SURFACE LOW...AND ALONG THE WARM FRONT EXTENDING EWD ALONG/NEAR
THE NEB/KS BORDER. THIS IS AN AREA WHERE TORNADOES...POSSIBLY
STRONG...APPEAR LIKELY INTO THE LATE EVENING.

UPSCALE GROWTH OF CONVECTION IS LIKELY TO OCCUR LATE TONIGHT WITH AN
MCS OR TWO EVOLVING AND SPREADING EAST ACROSS THE PLAINS...SUSTAINED
BY 40-50KT LLJ. MAGNITUDE OF INSTABILITY FEEDING THIS ACTIVITY TO
THE NORTH OF THE CAPPING INVERSION SHOULD MAINTAIN A THREAT FOR HAIL
AND WIND DAMAGE EWD TO PARTS OF MN AND IA THROUGH EARLY FRIDAY.

..CARBIN/ROGERS.. 06/10/2010

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