Area Forecast Discussion
Issued by NWS Green Bay, WI

Home | Current Version | Previous Version | Graphics & Text | 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

FXUS63 KGRB 142332

Area Forecast Discussion
National Weather Service Green Bay WI
632 PM CDT Wed Mar 14 2018

Updated aviation portion for 00Z TAF issuance

.SHORT TERM...Tonight and Thursday
Issued at 230 PM CDT Wed Mar 14 2018

Passage of a cold front tonight will bring cooler weather regime
to the region and send temperatures down to at or a little below
normal for the end of the work week. The main forecast challenge
will be on temperatures as moisture availability is limited ahead
of the cold front.

The 19z MSAS surface analysis indicated one area of low pressure
located over west-central Upper MI with a weak surface trough
extended southwest through eastern WI to southwest WI. Another
area of low pressure was situated over eastern Ontario with a cold
front stretched west-southwest to just north of MN. Current
visible satellite imagery showed that mid clouds had exited WI,
leaving sunny skies over the area. However, a band of low clouds
associated with the cold front was making a push south.

Mostly clear conditions to continue this evening until the cold
front moves through the region. The combination of CAA and north-
northwest winds will bring the cooler air mass into northeast WI
starting tonight and persist for the next couple of days. The
main impact from the cold front will be an increase in clouds and
potential for lake effect snow showers for far northern WI (mainly
Vilas County). Any accumulations would be limited by some ice
still over Lake Superior and a rather narrow DGZ layer. For now,
have accumulations over the Vilas County snowbelt at 1/2" of less.
The rest of northeast WI will remain dry tonight under partly to
mostly cloudy skies. Min temperatures to range from the middle
teens north, lower to middle 20s east-central WI.

Any lake effect snow showers will gradually come to an end on
Thursday as high pressure begins to build south from western
Ontario and inversion heights drop to around 3K feet. As the drier
air starts to overspread the region, expect any cumulus that tries
to form in the morning to dissipate, leaving mostly sunny skies
for the afternoon. 8H temperatures are still cold (-12 to -6C in
the afternoon), thus only expect max temperatures to reach the
middle 20s to around 30 degrees north, upper 20s to lower 30s near
Lake MI and middle to upper 30s south.

.LONG TERM...Thursday Night Through Wednesday
Issued at 230 PM CDT Wed Mar 14 2018

Expect little or no significant weather from Thursday night into
the middle of next week.

The 12Z model runs showed a mid level ridge moving east across the
Plains while getting squeezed between two major troughs before
reaching the western Great Lakes on Friday. The NAM, GFS and ECMWF
all had a closed 500 mb anticyclone developing to our northwest,
helping to keep the next mid level short wave and surface system
far enough to the south to prevent any precipitation from reaching
the forecast area. Another surface system is forecast to pass
south of Wisconsin early next week. There is a slight chance for
light rain or light snow in southern Manitowoc County Monday
afternoon into Monday evening as it passes. Models had enough
differences by then to lower confidence considerably.

Above normal high temperatures are expected for the weekend under
surface high pressure. Highs should be a bit below normal for the
rest of the period.

.AVIATION...for 00Z TAF Issuance
Issued at 632 PM CDT Wed Mar 14 2018

Skies will start out clear over most of the area this evening, but
clouds with bases between 3500 and 4500 feet will arrive from the
north later tonight. MVFR ceilings are possible mostly north of a
line from Rhinelander to Green Bay for several hours late tonight
and early Thursday. Should be VFR by Thursday afternoon with good
flying weather continuing through the end of the week in most of
northern Wisconsin.




SHORT TERM.....Kallas
AVIATION.......RDM is the U.S. government's official web portal to all federal, state and local government web resources and services.