Sunday, September 28, 2008

MESO: Mesoscale Discussion 2296

ACUS11 KWNS 282035
SWOMCD
SPC MCD 282034
MNZ000-SDZ000-NDZ000-NEZ000-282230-

MESOSCALE DISCUSSION 2296
NWS STORM PREDICTION CENTER NORMAN OK
0334 PM CDT SUN SEP 28 2008

AREAS AFFECTED...PORTIONS NRN NEB...SERN ND...CENTRAL/ERN
SD...W-CENTRAL/SWRN MN.

CONCERNING...SEVERE POTENTIAL...WATCH POSSIBLE

VALID 282034Z - 282230Z

AIR MASS IS DESTABILIZING ENOUGH ACROSS THIS REGION TO SUPPORT
SFC-BASED TSTMS...WITH LARGE HAIL BEING PRIMARY THREAT...AND
DAMAGING GUSTS ALSO POSSIBLE. PREDOMINANT STORM MODE SHOULD BE
MULTICELLULAR...ALTHOUGH BRIEF SUPERCELL STRUCTURES MAY FORM WITH
ACCORDINGLY ENHANCED HAIL POTENTIAL.

20Z SFC MESOANALYSIS INDICATES PRIMARY COLD FRONT FROM SERN ND SWWD
ACROSS EDMUNDS AND JACKSON COUNTIES SD AND OVER NEB PANHANDLE. THIS
FRONT IS FCST TO CONTINUE MOVING SEWD 20-25 KT ACROSS SD/NEB...AND
MORE SLOWLY ESEWD INTO WRN MN...THROUGH LATE EVENING...CATCHING UP
WITH WEAKER/LEADING COLD FRONT THAT IS ANALYZED FROM WEAK SFC LOW
NEAR ICR...SWWD ACROSS NEB SANDHILLS. WARM FRONT EXTENDS SE-NW
ACROSS ERN AND NRN NEB. QUASISTATIONARY OUTFLOW BOUNDARY FROM
MORNING ACTIVITY OVERLIES WARM FRONT AND IS ANALYZED IN ARC FROM
NEAR OFK WWD ACROSS GARFIELD COUNTY NEB THEN NWD ACROSS HOLT COUNTY.
20Z VIS IMAGERY INDICATES DEEP CONVECTIVE INITIATION ALONG SFC COLD
FRONT WHERE IT CROSSES LAKE OAHE IN N-CENTRAL SD...ROUGHLY 30 NNW
PIR. ADDITIONAL DEVELOPMENT IS EVIDENT OVER EXTREME SERN ND/NERN SD
AHEAD OF MAIN FRONT AND NE OF WARM FRONT. THESE TSTMS MAY REMAIN
ELEVATED BUT STILL POSE HAIL RISK MOVING EWD OVER MN.

MODIFIED RUC FCST SOUNDINGS SUGGEST SBCINH IS WEAKER FARTHER S
ACROSS S-CENTRAL SD INTO CHERRY COUNTY NEB...ALONG LEADING COLD
FRONT WHERE VIS IMAGERY ALSO INDICATES ENHANCED CU FIELD. INITIALLY
WIDELY SCATTERED TO ISOLATED CONVECTION SHOULD FILL INTO BKN/SW-NE
ALIGNED BAND DURING NEXT FEW HOURS AND MOVE SEWD OVER SRN/ERN
SD...SWRN MN AND N-CENTRAL NEB. 30-35 KT EFFECTIVE SHEAR MAGNITUDES
ARE EXPECTED OVER MOST OF AREA. HOWEVER...0-3 KM SRH VALUES ARE
ENHANCED TO 150-200 J/KG ALONG AND N OF OUTFLOW BOUNDARY AS COMPUTED
FROM LATEST NLG PROFILER WINDS...INDICATING ANY TSTMS THAT INTERACT
WITH THAT BOUNDARY WOULD HAVE GREATEST PROBABILITY OF SUPERCELL
DEVELOPMENT.

..EDWARDS.. 09/28/2008

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

ATTN...WFO...MPX...FGF...FSD...OAX...ABR...GID...LBF...UNR...

44700036 45699870 46219660 46099499 44759523 42909838
42129830 41949742 41309851 41770120 42300095 43640009

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