MESO: Mesoscale Discussion 1931

ACUS11 KWNS 042248
SWOMCD
SPC MCD 042248
NDZ000-MTZ000-050115-

MESOSCALE DISCUSSION 1931
NWS STORM PREDICTION CENTER NORMAN OK
0548 PM CDT TUE SEP 04 2007

AREAS AFFECTED...PORTIONS NERN/E-CENTRAL MT...NWRN AND EXTREME
W-CENTRAL ND.

CONCERNING...SEVERE POTENTIAL...WATCH UNLIKELY

VALID 042248Z - 050115Z

WIDELY SCATTERED TSTMS HAVE DEVELOPED RAPIDLY ALONG SFC COLD FRONT
-- ANALYZED AT 2215Z FROM EXTREME NWRN DANIELS COUNTY MT SWWD TO
ABOUT 10 E JDN...THEN SWWD TO FRONTAL WAVE LOW INVOF BIL.
ADDITIONAL DEVELOPMENT IS POSSIBLE ALONG COLD FRONT AS IT MOVES
EWD/SEWD OVER DISCUSSION AREA. ISOLATED SVR GUSTS AND HAIL ARE
POSSIBLE.

WARM FRONT ALSO IS ANALYZED FROM NEAR I-94 IN ERN/CENTRAL ND NWWD
ACROSS NERN MT...NE OF WHICH SFC THETAE DIMINISHES CONSIDERABLY.
MODIFIED GGW RAOB AND FCST RUC SOUNDINGS OVER THIS REGION INDICATE
NARROW CORRIDOR OF FAVORABLE BUOYANCY AHEAD OF SFC COLD FRONT...ATOP
DEEP AND WELL-MIXED BOUNDARY LAYER CONDUCIVE FOR MAINTAINING STG-SVR
GUSTS AND LARGE HAIL. SFC TEMPS LOW-MID 90S...DEW POINTS 50S F AND
8.5-9 DEG C/KM LOW-MIDLEVEL LAPSE RATES SUPPORT MLCAPES 1500-2000
J/KG. KINEMATIC PROFILES ALSO WILL BE AT LEAST MRGLLY
FAVORABLE...WITH 30-40 KT EFFECTIVE BULK SHEAR. VEERING WITH HEIGHT
IN LOW LEVELS YIELDS WELL-CURVED HODOGRAPHS WITH 150-200 J/KG OF 0-3
KM SRH...SUPPORTING POTENTIAL FOR ROTATION IN RELATIVELY DISCRETE
CELLS. MAIN LIMITING FACTORS MAY BE CONSIDERABLE STRENGTHENING OF
SBCINH WITH EWD EXTENT...AND DIABATIC COOLING OF NEAR-SFC LAYER
EXPECTED AFTER ANOTHER 2-3 HOURS.

PROGS REASONABLY INDICATE 30-35 KT SELY/SSELY LLJ DEVELOPING AFTER
ABOUT 02Z ACROSS WRN SD WITH 850 MB DEW POINTS 10-12 DEG C.
ASSOCIATED MOISTURE/INSTABILITY AND STORM-RELATIVE INFLOW MAY
SUPPORT SOME HAIL POTENTIAL WITH TSTMS...EVEN AFTER INFLOW-LAYER
PARCELS BECOME ELEVATED FOR STORMS MOVING OVER/NE OF SFC WARM FRONT.

.EDWARDS.. 09/04/2007

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

ATTN...WFO...BIS...BYZ...GGW...

46760714 47650639 49010603 48990152 47420302 46680570

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