Area Forecast Discussion
Issued by NWS Green Bay, WI

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000
FXUS63 KGRB 260015
AFDGRB

Area Forecast Discussion
National Weather Service Green Bay WI
615 PM CST Fri Nov 25 2016

Updated aviation portion for 00Z TAF issuance

.SHORT TERM...Tonight and Saturday
Issued at 235 PM CST Fri Nov 25 2016

A mid level trough was helping to produce light precipitation
today as it made its way across Wisconsin. The precipitation
should end in most locations by evening, but there could still be
a few light snow showers or flurries in north central Wisconsin
tonight in moist cyclonic flow.

12Z soundings from GRB and sites to the west showed plenty of low
level moisture trapped below an inversion. The back edge of the
low clouds, that was in northeast Montana on Wednesday, was
finally reaching central Minnesota early this afternoon. Also, it
is difficult to get rid of low clouds in November in this region,
so would expect the clouds to stick around throughout the night
and at least into Saturday morning. Do not think it will clear out
a lot during the afternoon but have decreasing clouds in the sky
grids. Confidence level still on the low side.

Have warmer temperatures in the forecast overnight due to the
clouds, generally a mix of some of the warmest guidance and the
previous forecast. Edged temperatures down a little for Saturday,
also due to clouds.

.LONG TERM...Saturday Night Through Friday
Issued at 235 PM CST Fri Nov 25 2016

High pressure will keep the last half of the weekend dry as
temperatures on Sunday warm back above normal as the
aforementioned high moves off to the east. While this high is
moving east, a strong slow moving low pressure system will develop
over the central plains. NWP models have come into better
agreement this run in progressing the low north-northeast over the
red river valley by Monday. This will bring a swath of light to
moderate rain from southwest to northeast Sunday night and Monday.
Given the copious moisture and isentropic lift across the western
Great Lakes from this system, therefore will continue the fairly
high POPs across the forecast area. The initial surge of moisture
from this system will be warm, with all rain expected during the
first part of next week.

Although the models start to diverge on Tuesday, they are still
close to maintain fairly high POPs into Monday night when an
occluded front sweeps through the western Great Lakes and another
swath of light to moderate rain tracks through the region. Cold
air filtering in behind the occluded front may cause snow to mix
in at times across the northern cwa late Monday night and into
Tuesday. However the dominant weather type is expected to be rain
with little to no snow accumulation during this period.

Behind the occluded front, precipitation chances will continue as
the surface low lingers across the western Great Lakes and
shortwaves rotate around the cut off upper level low situated over
the northwestern Great Lakes. A cooler atmosphere will mean more
snow will be in the forecast, however moisture will be at a
premium which should keep snowfall totals muted. A cold front will
push through the western Great Lakes Thursday night, which will
cause the main mid level low to push east and end precipitation
chances by next Friday. Although this portion of the forecast will
be cooler, temperatures will still be around normal for this time
of year.
&&

.AVIATION...for 00Z TAF Issuance
Issued at 615 PM CST Fri Nov 25 2016

Mainly mvfr conditions tonight into Saturday morning. Areas of
IFR cigs with patchy MVFR vsbys due to fog may develop overnight
across mainly North Central Wisconsin. A ridge of high pressure
building into the area later Saturday may attempt to improve
conditions to a higher end MVFR or lower end VFR conditions
Saturday afternoon.
&&

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

$$

SHORT TERM.....MG
LONG TERM......Kurimski
AVIATION.......TDH



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