Area Forecast Discussion
Issued by NWS Green Bay, WI

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FXUS63 KGRB 181643

Area Forecast Discussion
National Weather Service Green Bay WI
1143 AM CDT Sun Mar 18 2018

Updated aviation portion for 18Z TAF issuance

.SHORT TERM...Today...Tonight...and Monday
Issued at 250 AM CDT Sun Mar 18 2018

Surface analysis early this morning shows a ridge of high pressure
extending over minnesota into mid Mississippi valley region.
Meanwhile a low pressure system over Lake Superior will slide
east of the region today. This low pressure system will drag a
cold front over the area this afternoon and evening leading to
cooler temperatures for the start of the new work week along with
more clouds. Temperatures trends will be the primary issue during
this period.

With temperatures rising well above normal this afternoon, this
cold front will be likely be preceded with a back door pneumonia
type cold front dropping southward along the lakeshore today.
Temperatures along the bay and Lakeshore will turn sharply cooler
as winds turn northeast this afternoon.

Even though the cold front will sag into northern Wisconsin this
afternoon, a warm start today will still allow above normal temps
today before cooling late afternoon. Temperatures for Monday will
be about 15 degrees cooler than today/s high readings. Blustery
northeast winds will add to the chill.

.LONG TERM...Monday Night Through Saturday
Issued at 250 AM CDT Sun Mar 18 2018

Medium range models remain in good agreement tonite, and continue to
advertise a quiet pattern through much of the upcoming work week.
With the primary storm track expected to be south of the region,
Hudson Bay high pressure will likely lead to near or below normal
temperatures and below normal precipitation.  A general model blend
will continue to work for this forecast.

Monday night through Tuesday night...Mid and high clouds will be
increasing across the region ahead of various pieces of shortwave
energy moving across the northern Plains.  However, Hudson Bay high
pressure will be positioned over northern Ontario, and funneling dry
air below 700mb into eastern WI.  Therefore think most area will
remain dry, except for possibly the Lake Michigan shoreline where
instability may be just sufficient for a few flurries.  As the
shortwaves move across Wisconsin, progged soundings show that
saturation is looking more robust on Tuesday and Tuesday night.  As
a result, will have a slightly higher chance of flurries or light
snow, particularly over central and north-central WI, and also along
the Lake Michigan shoreline.  Under overcast conditions, temps to
fall back into the 30s.

Rest of the forecast...The shortwave energy will be slowly exiting
the region on Wednesday.  Weak convergent flow, however, will likely
keep broken to overcast conditions in place for much of Wednesday
and possibly into Wednesday night too.  But with mid-level moisture
peeling out, chances for light precipitation will be less than on
Tues/Tues night.  High pressure will return for Thursday, and think
should see more sunshine. Though it appears this sunshine could be
short-lived as models bring in the next chance of widespread precip
in the Fri-Sat period.

.AVIATION...for 18Z TAF Issuance
Issued at 1136 AM CDT Sun Mar 18 2018

VFR conditions will continue into this evening as mid and high
clouds move into the area. Later this evening into Monday morning,
MVFR CIGS are expected to develop behind a cold front. Some areas
of IFR conditions are across portions of north-central Wisconsin,
including KRHI. MVFR cigs will continue through much of Monday
morning and possibly into Monday afternoon before CIGS improve.

Otherwise, a backdoor cold front is expected to push southwestward
across the area late this afternoon or this evening. The front
should reach KGRB/KMTW/KATW between 21z and 23z, KRHI around 02z
and KAUW/KCWA around 03z. Not your typical Wisconsin cold front
as winds behind the front should turn to the northeast or east.
Gusty winds are expected in the 15 to 20 knot range, except at
KGRB/KATW where funneling down the bay of Green Bay and the Fox
River could push gusts over 20 knots at KGRB/KATW. Northeast winds
will stick around for the next few days.




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