MESO: Mesoscale Discussion 1267

ACUS11 KWNS 242047
SWOMCD
SPC MCD 242046
SDZ000-NDZ000-MTZ000-WYZ000-242315-

MESOSCALE DISCUSSION 1267
NWS STORM PREDICTION CENTER NORMAN OK
0346 PM CDT SUN JUN 24 2007

AREAS AFFECTED...S CNTRL AND SE MT...ERN WY...NW SD AND SW ND

CONCERNING...SEVERE POTENTIAL...WATCH LIKELY

VALID 242046Z - 242315Z

A FRONT HAS BECOME STATIONARY THIS AFTERNOON FROM EXTREME N CNTRL WY
ENE INTO CNTRL ND. N OF THE BOUNDARY...1-2 KM DEEP ENELY FLOW HAS
CARRIED VERY MOIST AIR /DEWPOINTS IN THE UPR 50S TO MID 60S F/ W
INTO THE HI PLNS OF SRN/ERN MT AND EXTREME NE WY. S OF THE
BOUNDARY...A DEEPLY MIXED ENVIRONMENT EXISTS ACROSS THE REMAINDER OF
ERN WY INTO FAR WRN SD...INVOF LEE TROUGH EXTENDING S THROUGH THE
BLACK HILLS. AT UPR LEVELS...SATELLITE AND VWP DATA SUGGEST
PRESENCE OF A WEAK IMPULSE NOW APPROACHING CNTRL PORTIONS OF MT AND
WY...EMBEDDED IN 30-40 KT SWLY MID LEVEL JET.

OBJECTIVE ANALYSES AND PRESENCE OF SCTD HIGH-BASED CONVECTION OVER
THE HIGHER TERRAIN OF NRN/ERN WY AND WRN SD SUGGEST THAT HEATING IS
RAPIDLY ERODING EXISTING CIN OVER REGION. CONTINUED HEATING AND
CONTINUED NE MOTION OF UPR IMPULSE SHOULD FURTHER REDUCE CIN. THIS
SHOULD HASTEN ROOTING OF THE HIGH-BASED CONVECTION INTO THE
INCREASINGLY UNSTABLE BOUNDARY LAYER ALONG AND N OF STATIONARY
FRONT.

GIVEN DEGREE OF SFC-BASED INSTABILITY EXPECTED ONCE CIN IS
ELIMINATED /AOA 2500 J PER KG/...AND 40-50 KT DEEP SWLY SHEAR...
EXPECT RAPID DEVELOPMENT OF SUPERCELLS. DISCRETE TO SEMI-DISCRETE
NATURE OF STORMS...RICH MOISTURE SUPPLY AND ENHANCED LOW-LEVEL
DIRECTIONAL SHEAR NEAR FRONT SUGGEST POSSIBILITY FOR TORNADOES...IN
ADDITION TO VERY LARGE HAIL/HIGH WIND...IN MT...FAR NRN WY...SW
ND...AND NW SD. FARTHER S...MORE WIDELY SCTD STORMS STRENGTHENING
IN DEEP-MIXED ENVIRONMENT COULD YIELD HIGH WIND AND HAIL.

.CORFIDI.. 06/24/2007

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

ATTN...WFO...ABR...BIS...UNR...BYZ...GGW...RIW...

44860255 44240401 44230638 44970757 45920827 46730666
47460371 47480134 45980131

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