Saturday, November 10, 2012

DAY1SVR: Day 1 Convective Outlook

ACUS01 KWNS 101632
SWODY1
SPC AC 101630

DAY 1 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
1030 AM CST SAT NOV 10 2012

VALID 101630Z - 111200Z

...THERE IS A SLGT RISK OF SVR TSTMS FROM THE UPPER MS VALLEY INTO
THE CENTRAL/SRN PLAINS...

...UPPER MS VALLEY INTO CENTRAL/SRN PLAINS...
VIGOROUS FULL LATITUDE UPPER TROUGH OVER THE WRN STATES WILL MOVE
EWD THROUGH TONIGHT REACHING THE NRN HIGH PLAINS INTO THE
CENTRAL/SRN ROCKIES BY 11/12Z. AT THE SURFACE...A COMPLEX PATTERN
CURRENTLY EXISTS WITH A LOW OVER SERN SD...WITH A WARM FRONT
EXTENDING EWD FROM THE LOW AND A FRONT ARCING SWD/WWD ACROSS ERN
NEB/NRN KS INTO THE PRIMARY LOW OVER NRN CO. THE SD LOW IS FORECAST
TO MOVE SLOWLY NWD AND WEAKEN AS THE WARM FRONT LIFTS NWD...WHILE
THE CO LOW MOVES ENEWD INTO CENTRAL NEB BY EVENING...THEN
ACCELERATES NEWD ACROSS THE UPPER MS VALLEY TONIGHT. THE FRONT OVER
ERN NEB SHOULD DISSIPATE NWD AS THE PRIMARY COLD FRONT MOVES EWD TO
A LINE FROM NERN MN/CENTRAL IA/CENTRAL OK AND SWRN TX BY THE END OF
THE PERIOD.

12Z REGIONAL RAOBS AND SATELLITE DATA INDICATE MODEST MOISTURE OVER
THE CENTRAL/SRN PLAINS WITH TPW VALUES APPROACHING 1.0 INCH.
SURFACE DEW POINTS OF 55-60F ARE ALSO COMMON IN THE LOW LEVEL MOIST
AXIS...AND THESE ARE UNLIKELY TO INCREASE SUBSTANTIALLY THIS
AFTERNOON. VISIBLE IMAGERY SHOWS CONSIDERABLE CLOUD FREE AREAS IN
THE WARM SECTOR FROM OK INTO SRN NEB AND IA AND THIS WILL ENHANCE
DIABATIC HEATING AND DESTABILIZATION THIS AFTERNOON. STEEP LOW/MID
LEVEL LAPSE RATES WILL COMBINE WITH CURRENT MOISTURE AND HEATING
RESULTING IN AN AXIS OF MLCAPE NEAR 1000 J/KG FROM WRN OK INTO SERN
NEB...HOWEVER...A CAPPING INVERSION WILL LIKELY INHIBIT CONVECTION
INITIATION EAST OF THE DRY LINE/COLD FRONT UNTIL LATE THIS AFTERNOON
AND EVENING. BY THEN MODEL CONSENSUS INDICATES THAT FORCING FOR
ASCENT WILL BE SUFFICIENT TO WEAKEN THE CAP WITH DISCRETE STORMS
DEVELOPING FROM EXTREME WRN OK ACROSS CENTRAL KS INTO SOUTH
CENTRAL/SERN NEB. STRONG LOW LEVEL AND DEEP LAYER SHEAR WILL
PROMOTE DEVELOPMENT OF INITIAL SUPERCELL STRUCTURES WITH A THREAT
FOR LARGE HAIL...DAMAGING WINDS...AND A FEW TORNADOES. STORMS ARE
EXPECTED TO MOVE RAPIDLY NEWD THROUGH THE EVENING HOURS WITH
CONTINUED SEVERE POTENTIAL...WITH SOME CONVECTION-ALLOWING MODELS
INDICATING SUPERCELL AND BOW ECHO STORM ACTIVITY. WITH
TIME...STORMS ARE EXPECTED TO TRANSITION TO LINEAR SEGMENTS WITH
SEVERE WINDS BECOMING THE PRIMARY THREAT DURING THE NIGHT.

..WEISS/MOSIER.. 11/10/2012

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