Area Forecast Discussion
Issued by NWS Green Bay, WI

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FXUS63 KGRB 201704

Area Forecast Discussion
National Weather Service Green Bay WI
1204 PM CDT THU OCT 20 2016

Updated aviation portion for 18Z TAF issuance

.SHORT TERM...Today...Tonight...and Friday
Issued at 338 AM CDT Thu Oct 20 2016

Cold advection and some cloud cover will produce cooler weather
today, with highs close to normal for this time of the year.
Temperatures aloft and wind direction are favorable for lake
effect clouds south of Lake Superior and near Lake Michigan and
the bay as well. In between there will be partly cloudy skies.

Lake effect clouds will continue across north central Wisconsin
tonight, and there may be some clouds near the lake Michigan
shore. There is a very slight chance of a sprinkle or snow flurry
in far north central Wisconsin but left out of forecast as winds
do not seem strong enough to bring lake effect precipitation that
far inland. Lows tonight should be pretty close to normal for this
time of the year.

Friday should be partly cloudy with temperatures near or just a
couple of degrees below normal.

.LONG TERM...Friday Night Through Wednesday
Issued at 338 AM CDT Thu Oct 20 2016

500MB pattern will continue with a west northwest flow across the
western Great Lakes into early next week, then a zonal pattern
will prevail by the latter half of next week.

Models continue to struggle with precipitation chances Sunday
into Sunday night across the north. Latest ECMWF is a little more
bullish with precipitation chances on the run tonight. Will hold
off for now and see if there is some continuity in the models with
respect to rain chances during the period. Otherwise, quiet
weather will prevail into early next week. Some timing differences
noted between the GFS/ECMWF models when rain arrive (Tue/Wed). GFS
is the quicker model while ECMWF would bring in rain late Tuesday
night and Wednesday. Also, the ECMWF has trended much further
south with the surface low track. If this trend holds true, the
risk for thunderstorms will be lower with main thunderstorm
activity to our south. Continued with slight chances for
thunderstorms at this point since there is plenty of time for
the models to shift the surface low track. Only made minor
adjustments to max/min temperatures to add detail with our
warm/cold bias sites depending on the time of day.

.AVIATION...for 18Z TAF Issuance
Issued at 1204 PM CDT Thu Oct 20 2016

High pressure will be building into the region through
the taf period.  However, cold north flow off Lake Superior will
continue to generate scattered to broken 2500-4000 ft cigs.  Ceilings
will continue to be lowest over north-central WI.



LONG TERM......Eckberg
AVIATION.......MPC is the U.S. government's official web portal to all federal, state and local government web resources and services.