MESO: Mesoscale Discussion 0910

ACUS11 KWNS 282002
SWOMCD
SPC MCD 282002
SDZ000-WYZ000-282230-

MESOSCALE DISCUSSION 0910
NWS STORM PREDICTION CENTER NORMAN OK
0302 PM CDT MON MAY 28 2007

AREAS AFFECTED...NERN WY...WRN SD

CONCERNING...SEVERE POTENTIAL...WATCH POSSIBLE

VALID 282002Z - 282230Z

CLUSTER OF STRONG TSTMS DEVELOPING OVER CENTRAL WY ARE EXPECTED TO
INCREASE IN INTENSITY AS THE MOVE INTO NERN WY OVER THE NEXT SEVERAL
HOURS. ADDITIONAL ISOLATED SVR TSTMS MAY OCCUR OVER THE BLACK HILLS
BEFORE 21Z...WHILE EVENTUALLY MOVING INTO THE LOWER ELEVATIONS OF
WRN SD BY 23Z...WHERE CINH CONTINUES TO WEAKEN. A WW MAY BECOME
NECESSARY OVER THE AREA LATER THIS AFTERNOON.

LATEST SFC ANALYSIS PLACES A SFC LOW OVER CENTRAL WY NEAR RIW. PER
SAT/RADAR IMAGERY A CLUSTER OF TSTMS HAVE DEVELOPED OVER CENTRAL WY
JUST AHEAD OF THIS SFC LOW IN A REGION OF MODERATE HEIGHT FALLS
AHEAD OF AN UPPER TROUGH OVER THE GREAT BASIN. ATTM...THE
ENVIRONMENT INVOF OF THIS CONVECTION WAS DRY WITH DEWPTS IN THE 30S.
HOWEVER...50-100 MILES DOWNSTREAM OF THIS ACTIVITY...AN AXIS OF
HIGHER DEWPTS /READINGS NEAR 50 F/ EXTENDED SW-NE ACROSS NERN WY.
RECENT OBJECTIVE ANALYSIS SHOWS THAT AROUND 1000 J/KG OF MLCAPE AND
LESS THAN 25 J/KG OF MLCINH EXISTS OVER MOST OF NERN WY. ADEQUATE
DEEP LAYER SHEAR/FORCING WILL EXIST AS MODERATE MID LEVEL WINDS
OVERSPREAD NELY WINDS AT THE SFC. WITH THE MODERATE INSTABILITY
EXPECTED TO SLOWLY INCREASE...AT LEAST AN ISOLATED SVR THREAT IS
EXPECTED TO DEVELOP WITH THIS ACTIVITY. FURTHER EAST...MODERATE
UPSLOPE FLOW INTO THE BLACK HILLS BEHIND A COLD FRONT ALONG WITH
WEAKENING CINH /AS THERMAL GRADIENT LAGS THE MAIN WIND SHIFT/ WILL
CONTINUE TO SUPPORT TSTM DEVELOPMENT. SIMILAR TO NERN WY...THE
MAGNITUDE OF THE VERTICAL SHEAR ALONG WITH MODERATE INSTABILITY WILL
SUPPORT AT LEAST AN ISOLATED SVR WIND/HAIL THREAT WITH THESE THE
STRONGEST TSTMS. GREATER INHIBITION OVER WRN SD /AWAY FROM THE
HIGHER TERRAIN/ WILL LIKELY KEEP THE SVR THREAT RELATIVELY CLOSE TO
THE BLACK HILLS THROUGH 23Z.

.CROSBIE.. 05/28/2007

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

ATTN...WFO...ABR...UNR...CYS...RIW...

44450437 44080653 43500667 43130659 42750623 42900507
43340283 43600184 43840131 44960124 45190186 45200231
44850314

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