Area Forecast Discussion
Issued by NWS Green Bay, WI

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FXUS63 KGRB 210326
AFDGRB

Area Forecast Discussion
National Weather Service Green Bay WI
1026 PM CDT Tue Jun 20 2017

Updated aviation portion for 06Z TAF issuance

.SHORT TERM...Tonight and Wednesday
Issued at 252 PM CDT Tue Jun 20 2017

Scattered showers and isolated thunderstorms will come to an end
late this afternoon or early this evening. Some of the showers and
storms could still produce some gusty winds to 35 mph, brief heavy
rain and small hail. Clouds should be on the decrease later this
evening with mostly clear skies expected overnight into Wednesday
morning. Some patchy fog is possible late tonight across much of
the area.

Any fog should burn off by 8 or 9 am. Clouds will be on the
increase by late morning as fair weather cumulus clouds should
develop and continue through the afternoon. By late afternoon,
low level jet is expected to crank up across Iowa and pointed
towards the area. Models differ with the onset of convection.
Most of the models have showers and storms arriving after 7 pm
Wednesday, except the ECMWF. Have added a small chance (20%)
across our southwest counties after 5 pm on Wednesday to account
for the quicker ECMWF model.

.LONG TERM...Wednesday Night Through Tuesday
Issued at 252 PM CDT Tue Jun 20 2017

Showers and thunderstorms will spread over the area Wednesday
night with a developing low level jet to 40 knots working into the
region. Deep layer shear develops as the upper jets slides over
the area. Much of the area is in a Marginal risk threat, with the
slight risk area just to the southwest within the area of greater
instability.  Trend of the progs is to slow down the cold front
Late Wednesday night into Thursday night as the upper flow
becomes more west to east. The greatest threat of strong storms
Thursday will be over the southern portion of the state near the
greatest instability and frontal location, but close to parts of
central and east central Wisconsin.

Progs drop the front further south on Friday but some progs do drop
a northern stream trough into northern Wisconsin for a chance
of a diurnal type convection.

Otherwise the pattern this upcoming weekend and early next week
indicates more chances of rain as an upper trough settles over
the Great Lakes region, with again mainly afternoon instability
type of convection with MU cape values peaking in the afternoons.
&&

.AVIATION...for 06Z TAF Issuance
Issued at 1024 PM CDT Tue Jun 20 2017

The guidance products really aren`t showing much fog, but
considering the amount of water from recent rains, will maintain a
mention of patchy fog overnight. Generally good flight conditions
are expected Wednesday once any fog dissipates. The next
significant aviation forecast issue will be the timing/coverage/
intensity of convection Wednesday evening--and the LLWS potential.
&&

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

$$

SHORT TERM.....Eckberg
LONG TERM......TDH
AVIATION.......Skowronski



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