[MCD] SWOMCD

[MCD at goshenarc.org]

ACUS11 KWNS 191727
SWOMCD
SPC MCD 191726 
ILZ000-IAZ000-WIZ000-MNZ000-192000-

MESOSCALE DISCUSSION 1730
NWS STORM PREDICTION CENTER NORMAN OK
1226 PM CDT MON JUL 19 2004

AREAS AFFECTED...SERN MN...SWRN WI AND ERN/CNTRL IA

CONCERNING...SEVERE THUNDERSTORM POTENTIAL 

VALID 191726Z - 192000Z

SEVERE POTENTIAL WILL INCREASE ACROSS SERN MN AND ERN/CNTRL IA
THROUGH THE AFTERNOON. A WEATHER WATCH MAY BE NEEDED BY 21Z.

A CLUSTER OF BACKBUILDING ELEVATED TSTMS HAS BEEN MAINTAINED THROUGH
THE MORNING ACROSS WCNTRL WI ALONG THE NOSE OF A SWLY LOW LEVEL JET.
 CONVECTIVE DEBRIS WILL SUSTAIN A DIFFERENTIAL HEATING BOUNDARY
ALONG THE WI/MN BORDER/ MS RVR VLY INTO MID-AFTERNOON.

MESOANALYSIS DEPICTS A 1007 MB LOW VCNTY KMSP WITH A WEAK TROUGH
EXTENDING SWWD INTO NWRN IA.  WARM SECTOR BETWEEN THE TROUGH AND
BOUNDARY ALONG THE MS RVR WILL CONTINUE TO HEAT THIS AFTERNOON.  AIR
MASS WILL BE CAPPED THROUGH ABOUT 21Z...BUT RUC40 FORECAST SOUNDINGS
SUGGEST THAT A SURFACE PARCEL WITH 85/70 TEMPERATURE/DEW POINT
RESPECTIVELY WILL RESULT IN A CAP BREECH.  GIVEN LOCALIZED SURFACE
CONVERGENCE VCNTY THE BOUNDARIES/LOW...SURFACE BASED INITIATION WILL
REMAIN LIKELY OVER SERN MN BY 21Z.  UPSCALE DEVELOPMENT INTO ONE OR
MORE MCS/S WILL BE POSSIBLE LATER IN THE AFTERNOON/EVENING ACROSS
ERN/CNTRL IA.  

GIVEN MIDLEVEL LAPSE RATES IN EXCESS OF 7 DEGREES C/KM AND A MOIST
BOUNDARY LAYER...MLCAPES WILL RANGE FROM 2500-3500 J/KG AND WILL SET
THE STAGE FOR RAPID TSTM DEVELOPMENT.  SWLY LOW LEVEL FLOW BENEATH
MODEST NWLY FLOW ALOFT /40+ KTS/ WILL CREATE 0-6KM SHEAR OF BETTER
THAN 40 KTS AND WILL BE SUFFICIENT FOR SUPERCELLS.  THE PRIMARY
SEVERE THREATS WILL BE LARGE HAIL AND DAMAGING WINDS.  ISOLD VERY
LARGE HAIL /2-2.5 INCHES/ MAY OCCUR WITH THE STRONGER SUPERCELLS. 
ISOLD TORNADOES COULD ALSO OCCUR WITH THE MORE DISCRETE CELLS/EARLY
DEVELOPMENT...THOUGH THE LOW LEVEL FLOW WILL BE SOMEWHAT WEAK.

..RACY.. 07/19/2004

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

ATTN...WFO...DVN...ARX...MPX...DMX...

41329388 44679413 44919292 44159159 42569046 41779033
41319119 41349241 

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