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[Printable]
025
ACUS01 KWNS 011253
SWODY1
SPC AC 011252

DAY 1 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
0752 AM CDT MON SEP 01 2014

VALID 011300Z - 021200Z

...THERE IS A SLGT RISK OF SVR TSTMS THIS AFTERNOON INTO TONIGHT
FROM LOWER MI TO THE NE OK/SE KS BORDER REGION...

...SUMMARY...
A FEW SEVERE STORMS WITH DAMAGING WINDS AND LARGE HAIL ARE EXPECTED
LATER TODAY FROM PARTS OF ILLINOIS INTO LOWER MICHIGAN.  A SOMEWHAT
LONGER-DURATION SEVERE STORM THREAT IS EXPECTED THIS AFTERNOON INTO
TONIGHT FROM THE KANSAS/OKLAHOMA BORDER REGION INTO SOUTHERN
MISSOURI...WHERE A COUPLE TORNADOES WILL ALSO BE POSSIBLE.
OTHERWISE...ISOLATED STORMS WITH STRONG WINDS ARE POSSIBLE ACROSS
THE CENTRAL HIGH PLAINS THIS AFTERNOON.

...SE KS/NE OK BORDER TO LOWER MI TODAY INTO TONIGHT...
A LEAD SHORTWAVE TROUGH OVER THE UPPER MS VALLEY THIS MORNING WILL
MOVE NEWD OVER UPPER MI BY THIS AFTERNOON...WHILE AN UPSTREAM WAVE
OVER ID/WY PROGRESSES EWD TO THE CENTRAL HIGH PLAINS THIS AFTERNOON
AND THE MID MS VALLEY BY SUNRISE TUESDAY.  AT THE SURFACE...AN
ASSOCIATED COLD FRONT WILL MOVE EWD ACROSS IA/WI TODAY TO WRN LOWER
MI AND NW IL BY THIS EVENING...WHILE THE SW EXTENT OF THE FRONT WILL
BECOME QUASI-STATIONARY NEAR THE KS/OK BORDER.

OUTFLOW FROM OVERNIGHT CONVECTION HAS PROGRESSED WELL AHEAD OF THE
SURFACE COLD FRONT...AND THE POTENTIAL FOR ADDITIONAL SEVERE STORM
DEVELOPMENT TODAY FROM NRN MO TO SE WI APPEARS TO BE DIMINISHING AS
A RESULT OF THE STABILIZING INFLUENCE OF THIS OUTFLOW...AS WELL AS
EARLY DAY PASSAGE OF THE LEAD SHORTWAVE TROUGH.  FARTHER E...A
BROKEN BAND OF PRE-FRONTAL CONVECTION WILL BE POSSIBLE THIS
AFTERNOON FROM NRN INDIANA INTO LOWER MI.  HERE...A FEW DAMAGING
GUSTS WILL BE POSSIBLE AS BOUNDARY LAYER DEWPOINTS NEAR 70 F AND
DAYTIME HEATING CONTRIBUTE TO MLCAPE AROUND 2000 J/KG...IN AN
ENVIRONMENT WITH SOME ENHANCEMENT TO DEEP-LAYER VERTICAL SHEAR WITH
THE LEAD SHORTWAVE TROUGH.

THE MORE FOCUSED SEVERE WEATHER THREAT AREA WILL BE FARTHER S FROM
THE OK/KS BORDER INTO SRN MO...ALONG THE RESIDUAL OUTFLOW BOUNDARY
FROM THE ONGOING STORMS IN MO/KS.  CONTINUED MOISTURE INFLUX INTO
THE BOUNDARY FROM THE S...IN CONJUNCTION WITH STRONG DAYTIME
HEATING...WILL MAINTAIN MLCAPE OF 2500-3000 J/KG ALONG THE SRN
FRINGE OF THE STRONGER WLYS...AND THE NRN FRINGE OF THE WARMER
ELEVATED MIXED LAYER/CAP.  DESTABILIZATION IN THE WARM SECTOR AND
CONTINUED WAA/ASCENT OVER THE REMNANT OUTFLOW/EFFECTIVE FRONT WILL
SUPPORT ADDITIONAL THUNDERSTORM DEVELOPMENT FROM N CENTRAL/NE OK AND
SE KS INTO SRN MO THIS AFTERNOON INTO TONIGHT.  THE MODERATE-STRONG
BUOYANCY AND EFFECTIVE BULK SHEAR OF 30-40 KT WILL SUPPORT A WSW-ENE
ORIENTED BAND OF STORMS WITH SOME EMBEDDED SUPERCELLS CAPABLE OF
PRODUCING LARGE HAIL/DAMAGING WINDS.  LOW-LEVEL SHEAR AND MOISTURE
WILL BE SUFFICIENT FOR SOME TORNADO RISK WITH STORMS ON THE
IMMEDIATE COOL SIDE OF THE BOUNDARY...AS SWD MOTION OF THE BOUNDARY
ENDS AND THE OUTFLOW AIR MASS MODIFIES BY THIS AFTERNOON.

...CENTRAL HIGH PLAINS THIS AFTERNOON..
HIGH-BASED AND LOW-TOPPED CONVECTION IS EXPECTED THIS AFTERNOON FROM
ERN WY INTO THE NEB PANHANDLE IN ADVANCE OF THE SPEED MAX MOVING EWD
FROM ID/WY.  BUOYANCY WILL BE LIMITED BY POOR LOW-LEVEL
MOISTURE....BUT SUFFICIENT DEEP-LAYER SHEAR FOR SUPERCELLS SUGGESTS
ORGANIZED STORMS WITH SOME RISK FOR STRONG OUTFLOW WINDS.

..THOMPSON/MOSIER.. 09/01/2014





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