MESO: Mesoscale Discussion 2086

ACUS11 KWNS 230612
SWOMCD
SPC MCD 230612
MOZ000-ARZ000-230845-

MESOSCALE DISCUSSION 2086
NWS STORM PREDICTION CENTER NORMAN OK
0112 AM CDT TUE OCT 23 2012

AREAS AFFECTED...PORTIONS W-CENTRAL/SWRN MO.

CONCERNING...SEVERE POTENTIAL...WATCH UNLIKELY

VALID 230612Z - 230845Z

PROBABILITY OF WATCH ISSUANCE...5 PERCENT

SUMMARY...CLUSTER OF TSTMS MAY OFFER THREAT FOR DAMAGING GUSTS
THROUGH ABOUT 08Z...ALONG WITH CONDITIONAL/BRIEF TORNADO RISK.
THREAT APPEARS TOO LOW AND CONFINED IN TIME/SPACE FOR WW.

DISCUSSION...SFC MESOANALYSIS SHOWS WEAK/RESIDUAL/QUASISTATIONARY
FRONTAL ZONE FROM W-CENTRAL MO SSWWD ACROSS NERN AND S-CENTRAL OK.
THIS FRONT SHOULD CONTINUE TO WEAKEN THROUGH REMAINDER OVERNIGHT
HOURS...BUT WILL DEMARCATE WRN PORTION OF NARROW MOIST PLUME...AXIS
OF WHICH PRECEDES FRONT BY ABOUT 50 NM. BOUNDARY-LAYER THETAE
DECREASES SUBSTANTIALLY WITH EWD EXTENT THROUGH OZARKS...I.E. SFC
DEW POINTS UPPER 60S F NEAR MOIST AXIS TO MID 50S IN FLP/UNO AREAS.
TSTMS OVER DISCUSSION AREA HAVE DEVELOPED AS STRONGEST DEEP-LAYER
ASCENT -- ASSOCIATED WITH MID-UPPER LEVEL SHORTWAVE TROUGH NOW
CROSSING WRN MO -- JUXTAPOSES WITH MOIST AXIS...OPTIMIZING BUOYANCY
THAT NONETHELESS IS MRGL. MODIFIED FCST SOUNDINGS SUGGEST SOME
WEAKENING OF STABLE LAYER BETWEEN 700-850 MB THAT CHARACTERIZED
REGIONAL 00Z RAOBS...PERMITTING EFFECTIVELY SFC-BASED PARCELS NEAR
MOIST AXIS...PRIMARILY OVER SWRN MO. ABOVE THAT...MLCAPE UP TO 500
J/KG AND MUCAPE 500-1000 J/KG ARE EVIDENT...ALONG WITH LLJ-ENHANCED
EFFECTIVE SRH OF 200-400 J/KG. RELATIVELY WEAK MIDLEVEL
WINDS...HOWEVER...LIMIT DEEP SHEAR...WITH EFFECTIVE SHEAR MAGNITUDES
ONLY 20-30 KT OVER MOST OF THIS AREA.

GIVEN THESE MIXED SIGNALS...NET EFFECT SHOULD BE CONTINUATION OF
MESSY AND MOSTLY MULTICELLULAR/CLUSTERED STORM MODES...BUT WITH
POTENTIAL FOR BRIEF/EMBEDDED MESOCYCLONE DEVELOPMENT. AS PLUME OF
STRONGEST LARGE-SCALE ASCENT SHIFTS NE OF RICHEST NEAR-SFC
MOISTURE...CONVECTION WILL SHIFT EWD AND NEWD ACROSS CENTRAL/SRN MO
AND BECOME MORE ELEVATED IN NATURE.

..EDWARDS/HART.. 10/23/2012

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

ATTN...WFO...LZK...SGF...EAX...TSA...

LAT...LON 36499419 38089381 38869355 38819314 38209291 37379275
36529277 36269338 36229382 36359410 36499419

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