MESO: Mesoscale Discussion 1660

ACUS11 KWNS 242003
SWOMCD
SPC MCD 242003
NEZ000-COZ000-WYZ000-242130-

MESOSCALE DISCUSSION 1660
NWS STORM PREDICTION CENTER NORMAN OK
0303 PM CDT FRI JUL 24 2009

AREAS AFFECTED...SERN WY...PORTIONS OF WRN NEB AND THE
PANHANDLE...EXTREME NERN CO

CONCERNING...SEVERE POTENTIAL...WATCH UNLIKELY

VALID 242003Z - 242130Z

ISOLATED SEVERE THUNDERSTORMS ARE POSSIBLE THIS AFTERNOON/EVENING
OVER FAR SERN WY AND PORTIONS OF WRN NEB AND THE PANHANDLE...AS WELL
AS EXTREME NERN CO. AT THIS TIME...A WW DOES NOT APPEAR NECESSARY.

RADAR IMAGERY INDICATES A BAND OF SHOWERS AND ISOLATED THUNDERSTORMS
ARE MOVING E THROUGH A SHORTWAVE RIDGE AXIS OVER CO AND WY.
MEANWHILE AT THE SURFACE...A COLD FRONT TRAILING WSW FROM A SURFACE
CYCLONE OVER THE GREAT LAKES REGION IS BEGINNING TO STALL OVER THE
CENTRAL HIGH PLAINS. AT 19Z...THIS FRONT WAS POSITIONED ROUGHLY FROM
50 W OF TOR IN SERN WY ESEWD TOWARD KOGA AND KLBF IN WRN NEB...WHERE
A NARROW ZONE OF CUMULUS IS BEGINNING TO TAKE SHAPE. STRONG SURFACE
HEATING IS OCCURRING ALONG THIS FRONTAL BOUNDARY...WHILE UPPER 60S
DEWPOINTS ALONG THE CENTRAL NEB PORTION OF THE FRONT TRANSITION TO
40S AND 50S OVER THE PANHANDLE...AND 30S OVER NERN CO. A PLUME OF
STEEP MID LEVEL LAPSE RATES OVERSPREADING THE REGION COMBINED WITH
PROGRESSIVELY DEEPER MOISTURE OVER NEB IS CONTRIBUTING TOWARD A
MODERATELY UNSTABLE ENVIRONMENT CENTERED ALONG THE FRONTAL BOUNDARY.

CURRENT THINKING IS THAT HIGH BASED SHOWERS/STORMS WITHIN THE DEEPLY
MIXED AIRMASS OVER SERN WY WILL MOVE ESE ALONG THE FRONTAL BOUNDARY
INTO WRN NEB AND THE PANHANDLE...AT WHICH POINT UPDRAFTS SHOULD
DEEPEN AND INTENSIFY. ELY LOW LEVEL FLOW ALONG AND N OF THE BOUNDARY
VEERS TO NWLY IN THE MID/UPPER LEVELS...WHICH WILL YIELD
SUFFICIENTLY STRONG VERTICAL WIND SHEAR PROFILES FOR SUPERCELLS.
THIS SHEAR...COMBINED WITH STEEP MID LEVEL LAPSE RATES AND
INCREASING CAPE WITH EWD EXTENT MAY PROMOTE AN ISOLATED LARGE
HAIL/DAMAGING WIND THREAT DURING THE AFTERNOON/EVENING. AT THIS
TIME...COVERAGE DOES NOT APPEAR TO BE GREAT ENOUGH TO WARRANT A WW.

..GARNER.. 07/24/2009

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

ATTN...WFO...LBF...GLD...BOU...CYS...

LAT...LON 40880065 40580077 40380236 40470360 40760476 41640525
42230494 42470413 42360294 41450100 40880065

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