MESO: Mesoscale Discussion 1790

ACUS11 KWNS 042311
SWOMCD
SPC MCD 042310
MTZ000-050115-

MESOSCALE DISCUSSION 1790
NWS STORM PREDICTION CENTER NORMAN OK
0610 PM CDT SAT SEP 04 2010

AREAS AFFECTED...PORTIONS CENTRAL/ERN MT.

CONCERNING...SEVERE POTENTIAL...WATCH UNLIKELY

VALID 042310Z - 050115Z

WIDELY SCATTERED TSTMS ARE EXPECTED TO CONTINUE DEVELOPING FOR
ANOTHER 2-3 HOURS ON BOTH SIDES OF SFC FRONTAL ZONE OUTLINED BELOW.
MOST INTENSE CELLS MAY PRODUCE HAIL OR DAMAGING GUSTS...HOWEVER LACK
OF MORE ROBUST MOISTURE...CONVECTIVE ORGANIZATION AND COVERAGE
SHOULD PRECLUDE NEED FOR WW.

SFC MESOANALYSIS SHOWS LOW BETWEEN JDN-BIL...WITH OCCLUDED FRONT
NEWD BETWEEN GGW-OLF...AND COLD FRONT SWWD BETWEEN BTM-DLN. LOW IS
EXPECTED TO MIGRATE ESEWD ACROSS SERN MT...ROUGHLY ALONG WARM
FRONTAL ZONE THAT EXTENDS FROM LOW INTO BLACK HILLS REGION. CROSS
SECTIONS OF THERMODYNAMIC PROFILES E OF OCCLUDED FRONT AND N OF WARM
FRONT INDICATE DEEP/WELL-MIXED BOUNDARY LAYERS SUITABLE FOR
MAINTENANCE OF HAIL AND STG-SVR GUSTS TO SFC...BENEATH ABOUT 100-500
J/KG MLCAPE. THESE DATA ALSO INDICATE SOMEWHAT WEAKER LAPSE RATES
AND DRIER LOW-LEVEL AIR WITH EWD EXTENT...WHICH ALSO IS EVIDENT IN
RUC FCST SOUNDINGS AND SFC ANALYSIS. THIS RESULTS IN ABSENCE OF
MLCAPE OVER EXTREME ERN MT. ALTHOUGH AT LEAST MARGINALLY FAVORABLE
BUOYANCY WILL SHIFT EWD SOMEWHAT ACROSS ERN MT...ACTIVITY WILL ENTER
LESS FAVORABLE AIR MASS E OF LONGITUDE OF MLS. SOMEWHAT HIGHER
THETAE IS EVIDENT BEHIND COLD/OCCLUDED FRONT...WHERE RICHER
LOW-LEVEL MOISTURE OFFSETS CAA AND WEAKER DIABATIC HEATING TO YIELD
SOMEWHAT BROADER AREA OF 200-500 J/KG MLCAPE AWAY FROM CONVECTIVE
OUTFLOWS. ON BOTH SIDES OF FRONT...HOWEVER...COMBINATION OF
EXPANDING OUTFLOW COVERAGE WITH TIME...AND SFC DIABATIC
COOLING...WILL REDUCE POTENTIAL FOR SEVERE TSTMS THIS EVENING AFTER
ABOUT 03Z.

..EDWARDS.. 09/04/2010

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

ATTN...WFO...BYZ...GGW...TFX...

LAT...LON 46841127 47881077 48380903 48230546 47060489 46170567
45980891 46181089 46841127

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