Area Forecast Discussion
Issued by NWS Green Bay, WI

Home | Current Version | Previous Version | Text Only | Print | Product List | Glossary Off
Versions: 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50

000
FXUS63 KGRB 261734
AFDGRB

Area Forecast Discussion
National Weather Service Green Bay WI
1234 PM CDT MON SEP 26 2016

Updated aviation portion for 18Z 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 18Z TAF Issuance
Issued at 1234 PM CDT Mon Sep 26 2016

A strong system located just north of Lake Superior will continue
to bring gusty winds to northeast Wisconsin this afternoon. Gusts
to around 35 knots can be expected, especially over central and
east-central WI where better mixing to bring stronger winds down
to the surface. Otherwise, cigs are forecast to range from MVFR
north to VFR south this afternoon with light rain showers mainly
confined to northern WI.

The gusty winds are expected to diminish this evening as mixing
subsides upon sunset. MVFR cigs with scattered rain showers will
continue across the north, while cigs to remain VFR with only a
spotty shower or a few sprinkles in the south.

The nearly vertically stacked system is only forecast to sink
south into Upper Michigan on Tuesday. This should bring a repeat
of both clouds and precipitation to the region, although more
clouds and a better chance of seeing precipitation to reach
central and east-central WI. Winds are not expected to be as
strong on Tuesday with more clouds inhibiting mixing.
&&

.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.......Kallas
MARINE.........Kurimski


USA.gov is the U.S. government's official web portal to all federal, state and local government web resources and services.