Area Forecast Discussion
Issued by NWS Green Bay, WI

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106
FXUS63 KGRB 261059
AFDGRB

Area Forecast Discussion
National Weather Service Green Bay WI
559 AM CDT MON SEP 26 2016

Updated aviation portion for 12Z TAF issuance

.SHORT TERM...Today...Tonight...and Tuesday
Issued at 318 AM CDT Mon Sep 26 2016

Surface analysis shows an occluded front has cleared the cwa early
this morning. Temperatures behind this front will be noticeably
cooler, as 850 mb temperatures plummet to the low single digits
above zero. This will cause temperatures to fall a good 5 to 10
degrees below normal, giving the area its first real taste of
fall.

The low associated with this front will remain situated over the
northwestern Great Lakes for the next few days, causing a very
tight pressure gradient across the western Great Lakes. Surface
winds are expected to gust to 25 to 35 mph at times, which could
make driving high profile vehicles difficult on north-south
roadways.

Along with the surface low remaining over the region, the mid
level low will also meander around the northwestern Great Lakes
during this period as it becomes closed off. This will bring a
continued chance for showers today and Tuesday as several
shortwaves tracking around this large low move through the cwa
under cyclonic flow. The best chances for showers will be across
north-central Wisconsin, which will be closer to the mid level
low and be in the most favorable area for dynamics to take
advantage of the lingering moisture across the region.

.LONG TERM...Tuesday Night Through Sunday
Issued at 318 AM CDT Mon Sep 26 2016

The upper low across the western Great Lakes will be the main
concern early in the period, then possibly again over the weekend.
Upper low will be swinging southward across the area Tuesday
night, then south of the forecast area on Wednesday. Showers will
linger into Wednesday. The chances for showers will come to an end
from north to south as drier air works into the region.

High pressure builds into the region Wednesday night through
Friday. Like last night, the models diverge on what will happen
over the weekend. The ECMWF model shifts the low north and west
and would bring precipitation into the area as early as Friday and
continues over the weekend. With position of the upper low, think
precipitation would not move back into the area until Friday night
at the earliest. The other models continue a dry forecast. Did add
a small chance of showers Saturday and Saturday night to account
for the ECMWF scenario. Confidence is low on the ECMWF solution
at the moment. Below normal temperatures are expected at the
beginning of the period. Temperatures should then return to or
above normal by the weekend.
&&

.AVIATION...for 12Z TAF Issuance
Issued at 558 AM CDT Mon Sep 26 2016

Gusty winds are expected during the TAF period in the wake of a
strong cold front exiting the region. Gusts of 25 to 30 knots are
likely, mainly in the late morning and afternoon. In addition,
wrap-around showers will continue to work their way into north-
central and far northeast WI this morning, and remain over the
northwoods region through this evening. Farther south, the showers
are expected to be more isolated. MVFR conditions should prevail
over north central and far northeast WI through most of the TAF
period. VFR conditions are anticipated over most of eastern WI.
&&

.MARINE...
Issued at 318 AM CDT Mon Sep 26 2016

Gusty west winds are expected Today into Tuesday behind a
departing cold front. Gale force gusts are possible at times
this afternoon and tonight across the coastal waters of northern
Door County. Winds should begin to decrease later Tuesday
afternoon and Tuesday night. In addition, cold air aloft will
create conditions favorable for waterspouts later Tuesday night
into Wednesday.
&&

.GRB WATCHES/WARNINGS/ADVISORIES...
NONE.
&&

$$

SHORT TERM.....Kurimski
LONG TERM......Eckberg
AVIATION.......Kurimski
MARINE.........Kurimski



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