Area Forecast Discussion
Issued by NWS Green Bay, WI

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FXUS63 KGRB 250751
AFDGRB

Area Forecast Discussion
National Weather Service Green Bay WI
251 AM CDT THU AUG 25 2016

Forecast discussion for routine morning forecast issuance

.SYNOPSIS...
Issued at 248 AM CDT Thu Aug 25 2016

A couple days of quiet weather, then rain returns for the
weekend.

On the large scale, ridges are located over the eastern Pacific
and over the southeastern United States, with a trough extending
from northeast of Hudson Bay to the intermountain West. The main
change during the period will be for the southern portion of the
trough to weaken, allowing for a fairly zonal band of westerlies
to set up across the northern CONUS and southern Canada by early
next week.

Temperatures will still be above normal today, briefly drop back
to near seasonal normals for Friday and Saturday, then return to
modestly above normal for the rest of the period. Though
confidence in estimating total precipitation is low, the most
likely result is AOB normal amounts simply because there seems to
be only one substantial opportunity for precipitation. That will
come with the system crossing the area this weekend.
&&

.SHORT TERM...Today...Tonight...and Friday
Issued at 248 AM CDT Thu Aug 25 2016

Convection firing with weak mid-level shortwave crossing the
region has remained south of the area thus far, and see no reason
to expect that to change. Will stick with dry forecast for today
into tonight. By late tonight, some precipitation with the tail of
a much stronger trough crossing southern Canada will be
approaching from the west. There is a chance it will graze the far
northern part of the forecast area early Friday, so kept the
slight chance of showers for that area that was in the previous
forecast.

After a relatively warm start and with quite a bit of sunshine
today, temperatures should again warm to above normal levels
despite some cold air advection. The low temperature forecast for
tonight is rather tricky. A surface ridge will be edging into the
area, so winds will drop off. With drier air in place by then,
stuck with low temps from the previous forecast despite the fact
they were lower than virtually all of the guidance products. The
north could drop off even more, but that`s not a given as clouds
ahead of Canadian shortwave will probably arrive at some point.
Some patchy fog is also possible, mainly in central Wisconsin.

.LONG TERM...Friday Night Through Wednesday
Issued at 248 AM CDT Thu Aug 25 2016

The main concern for this period will be thunderstorm chances
Friday night through the weekend. Except for the latest Canadian
model, the remainder of the models would support a faster arrival
of the rain Friday night. Have increased rain chances from 06z-12z
Saturday and later shifts may need to increase them even more.
Showers and thunderstorms are expected on Saturday as low pressure
moves across the region. Have gone with high end likely chances
for rain. At some point, categorical pops will be needed as system
moves across the region. Showers and a few thunderstorms will
linger into Saturday evening with only a few showers expected
early Sunday morning. The severe potential for Saturday is
somewhat muddled, thus continued the uncertainty wording in the
Hazardous Weather Outlook (HWO).

High pressure will dominate the weather pattern Sunday night and
Monday. Some difference in when the next chance of rain would
arrive next week. The new EC model would suggest a chance on
Tuesday. Will let later model runs close on a solution, thus no
major chances for early next week.
&&

.AVIATION...for 12Z TAF Issuance
Issued at 248 AM CDT Thu Aug 25 2016

Generally good flight conditions are expected as drier air moves
into the area. Patchy fog is possible tonight.
&&

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

$$

SYNOPSIS.......Skowronski
SHORT TERM.....Skowronski
LONG TERM......Eckberg
AVIATION.......Skowronski



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