SPC MD 1513



MD 1513 CONCERNING SEVERE POTENTIAL…WATCH POSSIBLE FOR NORTHEAST IOWA…SOUTHEAST MINNESOTA AND SOUTHWEST WISCONSIN

MD 1513 Image

Mesoscale Discussion 1513
NWS Storm Prediction Center Norman OK
1043 PM CDT Wed Jul 17 2019

Areas affected...northeast Iowa...southeast Minnesota and southwest
Wisconsin

Concerning...Severe potential...Watch possible 

Valid 180343Z - 180545Z

Probability of Watch Issuance...40 percent

SUMMARY...Elevated storms expected to increase in coverage and
intensity into the early morning from northeast IA into southeast MN
and southwest WI. Large hail appears to be the main threat, but
locally strong wind gusts are also possible. It remains uncertain if
severe threat will become sufficient for a WW, but trends will
continue to be monitored.

DISCUSSION...Late this evening, a reservoir of strong instability is
in place over the central Plains from NE to western IA. A
southwesterly low-level jet has strengthened to 40 kt resulting in
low-level theta-e advection and northeast destabilization with time
is expected across southern MN into western WI. A few elevated
showers are already initiating in the evolving warm advection regime
along the instability gradient across north central and northeast
IA, and additional development is likely farther northeast. The
thermodynamic environment with steep (7.5-8 C/km) mid level lapse
rates and 2500-3000 J/kg MUCAPE will promote a risk for large hail,
and 30-40 kt effective bulk shear may support some mid-level updraft
rotation in a few storms. The best hail threat will probably be
within a couple hours of initiation while storms are still discrete,
but activity might eventually congeal into a small cluster.

..Dial/Thompson.. 07/18/2019

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

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

LAT...LON   42189252 43039346 43869475 44659413 44669229 43899097
            42469106 42189252 

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