Friday, July 2, 2010

MESO: Mesoscale Discussion 1184

ACUS11 KWNS 021904
SWOMCD
SPC MCD 021903
MTZ000-022030-

MESOSCALE DISCUSSION 1184
NWS STORM PREDICTION CENTER NORMAN OK
0203 PM CDT FRI JUL 02 2010

AREAS AFFECTED...SWRN AND CENTRAL MT

CONCERNING...SEVERE POTENTIAL...WATCH LIKELY

VALID 021903Z - 022030Z

THREAT FOR LARGE HAIL AND DAMAGING WIND GUSTS IS EXPECTED TO
INCREASE ACROSS PORTIONS OF SWRN INTO CENTRAL MT DURING THE
AFTERNOON HOURS. A WW WILL LIKELY BE NEEDED.

UPPER IMPULSE OBSERVED IN WV IMAGERY IS RAPIDLY MOVING NEWD INTO
ALBERTA...WHILE SECOND DISTURBANCE IS DROPPING SEWD INTO ORE. THOUGH
STRONG LARGE SCALE ASCENT IS FORECAST TO EXIT NWD AWAY FROM MT WITH
THE ALBERTA SHORTWAVE...THERMALLY DIRECT CIRCULATION ASSOCIATED WITH
THIS FEATURE IS EXPECTED TO DRIVE LOW-LEVEL COLD FRONT SWD AND EWD
ACROSS CENTRAL MT INTO SRN AND ERN PORTIONS OF THE STATE BY 00Z.
MEANWHILE...WITH MOSTLY CLEAR SKIES IN PLACE ACROSS THE
AREA...SURFACE TEMPERATURES WILL CONTINUE TO WARM INTO THE 80S AHEAD
OF THE FRONT OVER ERN MT...WITH 60S AND 70S F NOTED OVER SWRN MT.
THIS HEATING WILL CONTRIBUTE TOWARD STRONG DESTABILIZATION OVER THE
HIGHER TERRAIN OF SWRN MT...WHERE CUMULUS FIELD IS BEGINNING TO
DEEPEN AT 1830Z PER VISIBLE SATELLITE IMAGERY.

GIVEN THIS ENVIRONMENT...THUNDERSTORM INITIATION WILL LIKELY OCCUR
OVER SWRN MT WITH FAVORABLE TERRAIN INDUCED CIRCULATIONS. STEEP
MID-LEVEL LAPSE RATES AND LOWEST 100 MB MEAN MIXING RATIO/S RANGING
FROM 8-11 G/KG WILL YIELD MLCAPE VALUES NEAR 500 J/KG BY MID
AFTERNOON. MID-LEVEL FLOW AROUND 40-50 KT WILL ALSO RESIDE NEAR THE
FRONTAL BOUNDARY...WHICH WILL CONTRIBUTE TOWARD EFFECTIVE BULK SHEAR
VALUES AOA 40 KT...FAVORABLE FOR ORGANIZED STORM DEVELOPMENT WITH A
THREAT FOR LARGE HAIL.

OVER NERN MT...STRONG CINH IS OBSERVED IN 18Z GGW RAOB...AND
POTENTIAL FOR ROBUST DESTABILIZATION IS IN QUESTION DUE TO MEAGER
LARGE SCALE ASCENT. AS A RESULT...STORM INITIATION WILL LIKELY BE
MORE GRADUAL THROUGH THE AFTERNOON GIVEN THE STRONGER CAP...WITH
DEVELOPMENT TAKING PLACE ALONG OR SLIGHTLY BEHIND THE SURGING COLD
FRONT. GIVEN DEEP LAYER FLOW/SHEAR MAINLY PARALLEL TO THE
FRONT...LONG STORM RESIDENCE TIMES ALONG THE BOUNDARY ARE
EXPECTED...SUGGESTING LINEAR ORGANIZATION TO THUNDERSTORMS WILL BE
PROBABLE. THE STEEP LAPSE RATE ENVIRONMENT AND STRONG DEEP SHEAR
WILL ALSO FAVOR LARGE HAIL WITH THE MORE ROBUST UPDRAFT CORES...IN
ADDITION TO A DAMAGING WIND THREAT WITH TIME.

..GARNER.. 07/02/2010

...PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT...

ATTN...WFO...BYZ...GGW...RIW...TFX...MSO...

LAT...LON 44921285 45371331 46371273 47171085 48270919 48190741
47420675 45910821 45051019 44921285

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