Sunday, September 28, 2008

DAY1SVR: Day 1 Convective Outlook

ACUS01 KWNS 281600
SWODY1
SPC AC 281557

DAY 1 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
1057 AM CDT SUN SEP 28 2008

VALID 281630Z - 291200Z

...THERE IS A SLGT RISK OF SVR TSTMS FOR A LARGE PORTION OF CENTRAL
AND EASTERN NE...

...NEBRASKA...
THE 12Z LBF SOUNDING DEPICTS THE PRESENCE OF CONSIDERABLE ELEVATED
INSTABILITY ALONG WITH STEEP MID LEVEL LAPSE RATES IN EXCESS OF
8C/KM. THIS ENVIRONMENT EVEN WITH THE CURRENT GENERALLY BENIGN
KINEMATICS IS SUPPORTING THIS MORNINGS VIGOROUS ELEVATED CONVECTION
NCENTRAL NE.

COLD FRONT AND LEE TROUGH ASSOCIATED WITH AMPLIFYING SK/MB IMPULSE
WILL REACH THE ERN DAKS/NW NEB BY LATE IN THE DAY. TSTMS SHOULD
FORM ALONG THE COLD FRONT IN ERN SD/SW MN...AND ALONG LEE TROUGH
ACROSS NRN AND CNTRL NEB...AS HEATING AND LOW LVL CONVERGENCE BREACH
FAIRLY STOUT EML CAP.

WITH SURFACE TEMPERATURES WARMING INTO THE MID 80S MLCAPES WILL
CLIMB TO AOA 2000 J/KG BY MID/LATE AFTERNOON. WHILE DEEP LAYER
SHEAR WILL REMAIN MARGINAL FOR SUPERCELLS...AROUND 30KT...THE
THERMODYNAMICS...COUPLED WITH VEERING SHEAR PROFILES SHOULD LEAD TO
DEVELOPMENT OF A FEW SEVERE STORMS BY LATE AFTERNOON. LARGE HAIL
WILL BE THE PRIMARY THREAT.

OVERALL SETUP SUGGESTS LIKELIHOOD FOR SCTD STRONG MULTICELL STORMS
...ALONG WITH A FEW BRIEF SUPERCELLS. CONTINUED STRENGTHENING OF
MEAN FLOW...DEVELOPING SWLY LLJ...AND ARRIVAL OF HEIGHT FALLS WITH
AMPLIFYING UPR TROUGH FURTHER SUGGEST THAT AN ISOLD/MARGINAL SVR
HAIL THREAT MAY PERSIST THROUGH LATE EVE AS STORMS CONSOLIDATE INTO
A CLUSTER THAT MOVES GENERALLY SE ACROSS ERN NEB/WRN IA.

..HALES/CROSBIE.. 09/28/2008

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