Sunday, August 3, 2008

MESO: Mesoscale Discussion 2019

ACUS11 KWNS 040138
SWOMCD
SPC MCD 040138
WIZ000-MNZ000-IAZ000-SDZ000-040345-

MESOSCALE DISCUSSION 2019
NWS STORM PREDICTION CENTER NORMAN OK
0838 PM CDT SUN AUG 03 2008

AREAS AFFECTED...PORTIONS ERN MN...NWRN IA.

CONCERNING...SEVERE POTENTIAL...WATCH POSSIBLE

VALID 040138Z - 040345Z

CONDITIONAL POTENTIAL REMAINS FOR RAPID/DEEP CONVECTIVE DEVELOPMENT
OVER THIS REGION. EMPHASIS WITH TIME WILL SHIFT N OF SFC WARM FRONT
OUTLINED BELOW...WITH SFC-BASED INITIATION BECOMING LESS PROBABLE
AFTER 03Z. DAMAGING WIND AND HAIL ARE LIKELY FROM ANY TSTMS THAT DO
DEVELOP...WHICH MAY BECOME SUPERCELLULAR GIVEN FAVORABILITY OF
KINEMATIC PROFILES. TORNADO POTENTIAL WOULD BE RELATIVELY MAXIMIZED
NEAR WARM FRONT AND BEFORE ABOUT 04Z...GIVEN MORE STABLE SFC AIR
MASS EXPECTED FARTHER N AND WITH TIME THIS EVENING.

SFC MESOANALYSIS SHOWS QUASISTATIONARY LOW JUST E FSD NEAR SWRN
CORNER MN...WITH COLD FRONT SWWD ACROSS LINCOLN/CLAY COUNTIES SD
INTO CENTRAL NEB...AND OCCLUDED FRONT COLLOCATED WITH INVERTED
TROUGH MOVING EWD OVER W-CENTRAL MN. LOW IS FCST TO BEGIN MOVING
EWD ALONG IA/MN BORDER DURING NEXT 2-3 HOURS...WITH COLD FRONT
DRIFTING SEWD INTO MORE OF SWRN MN AND NWRN IA. WARM FRONT --
INITIALLY ANALYZED EWD TO NEAR FRM THEN SEWD PAST MCW -- SHOULD
DRIFT NWD. MODIFIED SOUNDINGS SUGGEST INFLOW PARCELS AT OR VERY
NEARLY SFC BASED WILL REMAIN PRESENT WITHIN 50-60 NM N OF WARM FRONT
THROUGH EARLY EVENING...GIVEN VERY RICH BOUNDARY LAYER THETAE
EVIDENT IN FRONTAL ZONE. ASSOCIATED STRONG MOISTURE EXTENDS ABOVE
FRONTAL SFC ACROSS SRN MN IN SUPPORT OF POTENTIAL FOR ELEVATED SVR
DEVELOPMENT LATER THIS EVENING AS WELL. SFC DEW POINTS UPPER
70S/LOW 80S F...BENEATH STEEP MIDLEVEL LAPSE RATES OF EML...YIELD
MLCAPES 5000-6000 J/KG. FAVORABLE KINEMATIC ENVIRONMENT IS
CHARACTERIZED BY 40-50 KT EFFECTIVE SHEAR...WITH ENLARGED LOW LEVEL
HODOGRAPHS ALONG AND JUST N OF WARM FRONT. WHILE SUFFICIENT
CONVERGENCE ALONG WARM FRONT TO BREAK CAP REMAINS UNCERTAIN AT THIS
HOUR..EXPLOSIVE INTENSIFICATION TO SVR LEVELS IS LIKELY WITH ANY
SFC-BASED TSTMS THAT CAN FORM IN WARM FRONTAL ZONE OR ALONG COLD
FRONT.

OTHERWISE...STG BUOYANCY AND SHEAR ALSO WILL EXIST FOR ELEVATED
PARCELS ACROSS SRN MN INTO WRN WI N OF FRONT. LAST VIS IMAGERY
INDICATES INCREASING COVERAGE/DEPTH OF CONVECTIVE CLOUD ELEMENTS
FROM AROUND RWF EWD TOWARD WRN PORTIONS MSP AREA...POSSIBLY
REPRESENTING ZONE OF ENHANCED LIFT ATOP WARM FRONTAL SFC THAT MAY BE
STRENGTHENED FURTHER AS 35-40 KT LLJ EXPANDS/SHIFTS OVER
S-CENTRAL/SERN MN AND WRN WI.

..EDWARDS.. 08/04/2008

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

ATTN...WFO...ARX...MPX...DMX...FSD...

42529661 43289608 44399552 45109491 45549366 45459212
44749120 44069096 43559172 43089322 42499489

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