[MCD] SWOMCD

[MCD at goshenarc.org]

ACUS11 KWNS 012023
SWOMCD
SPC MCD 012020 
IAZ000-012215-

MESOSCALE DISCUSSION 2155
NWS STORM PREDICTION CENTER NORMAN OK
0320 PM CDT WED SEP 01 2004

AREAS AFFECTED...PARTS OF CNTRL/ERN IA

CONCERNING...CONVECTIVE TRENDS 

VALID 012020Z - 012215Z

POTENTIAL FOR CONVECTIVE DEVELOPMENT APPEARS TO BE INCREASING...
WITH PERHAPS ISOLATED/BRIEF SEVERE THREAT.

STRONG SURFACE HEATING...FOCUSED ALONG LOW-LEVEL THERMAL RIDGE AXIS
EXTENDING OUT OF THE NORTHERN PLAINS...AND EVAPOTRANSPIRATION HAVE
CONTRIBUTED TO CONSIDERABLE DESTABILIZATION OF BOUNDARY LAYER ACROSS
MUCH OF IOWA AND ADJACENT AREAS OF THE UPPER MISSISSIPPI VALLEY. 
THIS IS SOUTH OF WEAK FRONTAL ZONE ACROSS SOUTH CENTRAL MINNESOTA/
NORTH CENTRAL WISCONSIN...WHERE LOW-LEVEL FOCUS FOR CONVECTIVE
DEVELOPMENT IS UNCERTAIN.

HOWEVER...LATEST OBJECTIVE ANALYSIS INDICATES SUBSTANTIAL WEAKENING
OF CONVECTIVE INHIBITION IS ONGOING ACROSS IOWA.  THIS IS PERHAPS
AIDED BY MID-LEVEL FORCING FOR UPWARD VERTICAL MOTION ASSOCIATED
WITH ONE OF A SERIES OF WEAK WAVES EVIDENT IN LATEST WATER VAPOR
IMAGERY.  ADDITIONAL HEATING LATE THIS AFTERNOON IS EXPECTED TO
SUPPORT INITIATION OF AT LEAST ISOLATED CONVECTIVE DEVELOPMENT BY
22-23Z...MAINLY EAST OF THE DES MOINES AREA...WHERE MEAN MIXED LAYER
CAPE IS ON THE ORDER OF 2000 J/KG.  WEAK FLOW FIELDS/SHEAR PROFILES
WILL LIMIT OVERALL SEVERE THREAT...BUT THERMODYNAMIC ENVIRONMENT
APPEARS SUPPORTIVE OF MARGINALLY SEVERE HAIL...POSSIBLY GUSTY
WINDS...IN MOST VIGOROUS CONVECTION.

..KERR.. 09/01/2004

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

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

43109356 42609177 41879103 41009146 40869307 41449421
42789478 

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