Lake effect precipitation is expected to largely remain to our
east through most of the day Tuesday as a northwesterly fetch
continues over Lake Michigan. This does look to change, however,
as the flow veers more northerly down the lake Tuesday night as a
large area of surface high pressure begins to build into the Upper
Midwest. This should thus favor the best chance for lake effect
precipitation over Lake and Porter counties in northwestern IN for
a period Tuesday night. The potential even exists for the flow to
veer more north-northeasterly for a period late Tuesday night
into Wednesday morning, which could push any lake effect
precipitation into parts of the Cook county. Lake induced
thermodyamics on the lake will be quite impressive into Tuesday
night, with 850 mb to lake surface delta T`s near 20C and lake
induced equilibrium heights up to 26,000 feet. This suggests that
not only will lake effect showers be favored, but also possible
thunderstorms. Forecast guidance is also suggesting that a land
breeze convergence zone will develop over southern Lake Michigan
late Tuesday night into Wednesday morning, which would help focus
the development of thunderstorms into the southern and
southwestern shores of the lake. This also looks to be a favorable
setup for waterspouts on the lake during this period!