SPC MD 2049


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Mesoscale Discussion 2049
NWS Storm Prediction Center Norman OK
0503 PM CDT Tue Oct 01 2019

Areas affected...southern Wisconsin...northwestern Illinois...and
eastern Iowa

Concerning...Severe potential...Watch possible 

Valid 012203Z - 020000Z

Probability of Watch Issuance...60 percent

SUMMARY...Convective trends are being monitored for a potential WW
issuance across the region in the 1-2 hours.

DISCUSSION...Convection is gradually increasing/deepening across
southwestern Wisconsin and vicinity via latest radar mosaic and
satellite imagery.  Additionally, upstream storms have exhibited
supercellular characteristics across southwestern Iowa and are
moving northeastward toward the discussion area at a mean storm
motion of 235/35.  The airmass across the discussion area is
moderately unstable, with modest (7 deg C/km) mid-level lapse rates
and low to mid 70s F dewpoints supporting 1000-2000 J/kg MUCAPE. 
Deep shear is sufficient for storm organization, though low-level
shear is modest as evidenced by weak low-level wind fields in point
forecast soundings and minimal veering with height based on VAD data
and 18Z RAOB at DVN.  

Over time, observations and CAMs all suggest that storms will
increase in coverage from west to east across the discussion area,
with the environment supporting a risk for damaging wind gusts and
hail.  Additionally, as long as storms 1) maintain a cellular mode 
2) interact with a subtle west-to-east frontal/differential heating
zone across southern Wisconsin, and 3) persist long enough for
low-level flow to increase through the early evening, a few cells
may acquire updraft rotation and pose a tornado risk.  This risk may
be modulated by nocturnal boundary layer cooling, however.  Latest
thinking is that a Severe Thunderstorm Watch may be needed to cover
the attendant threats.  Convective trends will continue to be

..Cook/Guyer.. 10/01/2019

...Please see www.spc.noaa.gov for graphic product...


LAT...LON   43119231 43539183 43809099 43898992 43838890 43258821
            42418831 41738859 41278964 41089079 41049174 41379210
            42089221 42699231 42889235 43119231 

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