Area Forecast Discussion
Issued by NWS Milwaukee/Sullivan, WI
FXUS63 KMKX 200756
Area Forecast Discussion
National Weather Service Milwaukee/Sullivan WI
256 AM CDT THU OCT 20 2016
.TODAY AND TONIGHT...Forecast Confidence Is High.
Southern Wisconsin is in the entrance region of the 120 knot 250 mb
jet that increases to 145 knots over southeast canada. An Upper
level trough over Minnesota and the eastern central Plains digs as
it moves into Wisconsin tonight with the downstream jet moving off.
Some weak upper level divergence, especially southeast into the
early afternoon along with weak 700mb upward motion. As the 700mb
trough axis moves east downward motion dominates south central
this afternoon and southeast this evening. 700 mb RH decreases this
morning and is very dry by afternoon. Mid and low level cold
advection dominates. 850 mb temperatures drop to -5 northeast areas
late tonight. North northeast 850 mb winds become north northwest
and increase today.
North/northeast surface winds also become north along the lake and
northwest inland today. Wind speeds increase early this morning,
especially near the lake then diminish, especially inland this
Main concern is frost. Widespread frost with some freezing
temperatures south central, with lesser frost potential closer to
Lake Michigan where north winds will stay up.
Frost advisories will be in effect most areas.
.FRIDAY AND SATURDAY...Forecast Confidence...Medium
High pressure will bring mostly sunny to partly cloudy skies
Friday and Saturday. Highs temps will be below normal on Friday,
but will warm back up to around normal Saturday as southerly winds
develop on the back side of the high.
.SUNDAY THROUGH WEDNESDAY...Forecast Confidence...Medium
Low pressure is progged to move through Sunday. It still looks
like the best forcing will remain to the north of the surface low,
so expecting the dry weather to continue. High pressure will
follow the departing low for Monday.
Should see temps a few degrees above normal Sunday, falling back
to around normal or a couple degrees below normal Monday.
A stronger low will develop to the west on Tuesday, moving through
Tuesday night into Wednesday. This system should bring rain shower
chances both Tuesday and Wednesday. The models have backed off the
instability for southern Wisconsin, mainly keeping it west and
south of the forecast area as the low moves through. Dropped
thunder mention for now as a result.
Models are coming in quite a bit cooler for Tue/Wed, so trended
temps downward a bit. Did not lower too much for now though, as
much milder air will be just to the south and it will not take
much of a deviation to the north with the low to bring the milder
Some concern of MVFR ceilings moving into locations near Lake
Michigan through the morning with north to northeast winds
associated with the low moving up the Ohio River Valley. Otherwise
VFR conditions expected.
Small Craft Advisory for areas from North Point Lighthouse south
as North/northeast winds increase, with wave heights from
Milwaukee south expected to increase to advisory criteria by
daybreak. Latest wave model output indicates waves will diminish
to just below criteria late tonight.
WI...FROST ADVISORY from 1 AM to 8 AM CDT Friday for WIZ046-047-051-
LM...SMALL CRAFT ADVISORY until 3 AM CDT Friday for LMZ645-646.
SMALL CRAFT ADVISORY until 7 PM CDT this evening for LMZ643-644.
TODAY/TONIGHT AND AVIATION/MARINE...Hentz
Friday THROUGH Wednesday...DDV