md 0442 concerning severe potential

..watch likely for scntrl wi...nrn il


mesoscale discussion 0442
nws storm prediction center norman ok
0140 pm cdt mon apr 25 2016

areas affected...scntrl wi...nrn il

concerning...severe potential...watch likely 

valid 251840z - 252045z

probability of watch issuance...80 percent

summary...a severe threat appears likely to develop across scntrl wi
and nrn il this afternoon with severe storms increasing into the
early evening. large hail and wind damage are expected to be the
main threats although a brief tornado can not be ruled out. ww
issuance will likely be needed across the region.

discussion...latest sfc analysis shows a 1000 mb low over se mn with
a corridor of low-level moisture extending from ne mo into nw il and
srn wi. a stationary frontal boundary is located from near the sfc
low extending sewd across scntrl wi. sfc dewpoints along and south
of the boundary range from 55 to 60 f and sfc temps have risen into
the upper 70s and lower 80s f. this is contributing to mlcape
estimated by mesoscale analysis to be 500 to 1000 j/kg across nw il
with less instability across scntrl wi. instability should continue
to increase over the next few hours as low-level convergence becomes
enhanced along the boundary in scntrl wi. this should result in
scattered thunderstorm initiation over the next hour or so with
cells developing sswwd into nw il this afternoon.

the latest wsr-88d vwps in scntrl wi and nw il suggest moderate
deep-layer shear is in place with 0-6 km shear estimated near 40 kt.
this will support severe storm development with rotating cells
likely. supercells with large hail will be most likely in nw il on
the nern edge of a plume of steep mid-level lapse rates. hailstones
of greater than 2 inches in diameter will be possible. as cells
increase in coverage and congeal late this afternoon...a line of
storms is forecast to develop and move ewd to lake michigan by early
this evening. a 700 mb jet currently in ne ia will help with linear
organization and possibly bowing structures. any bowing line segment
should have potential for damaging wind gusts with a brief tornado
also possible.

..broyles/corfidi.. 04/25/2016

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

attn...wfo...iwx...grb...lot...mkx...dvn...arx...

lat...lon 41388834 41438965 41889019 42609002 43498983 43748976
44068948 44248889 44248810 43978709 42918627 41728675
41388834