Area Forecast Discussion
Issued by NWS Green Bay, WI

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929
FXUS63 KGRB 261105
AFDGRB

Area Forecast Discussion
National Weather Service Green Bay WI
605 AM CDT Wed Jul 26 2017

Updated aviation portion for 12Z TAF issuance

.SHORT TERM...Today...Tonight...and Thursday
Issued at 331 AM CDT Wed Jul 26 2017

Questions were numerous at the start of the shift, namely the
severe weather potential given the cloud cover over the western
Great Lakes region. Those questions seem to be answered just a few
hours later with showers and thunderstorms developing ahead of a
cold front slowly tracking through the area. With activity already
firing this morning and cloud cover expected to be abundant the
severe weather potential today appears to be minimal as it is
unlikely that enough instability will be able to build for strong
to severe storms this afternoon, which is in line with the
current SPC day 1 convective outlook. It appears showers and
thunderstorms will be possible at times throughout the day as the
cold front sinks south, with the best severe potential off to the
south where some clearing can be realized. The abundant cloud
cover will limit high temperatures to around 80 this afternoon.

Rain chances will diminish from north to south tonight as the cold
front sinks south and drier air advects in from the north. The
quicker arrival of the front across the north will mean lows will
drop into the upper 50s across the north, with lower to middle 60s
across east-central Wisconsin given a later fropa and lingering
cloud cover.

Thursday poses an interesting forecast during the afternoon hours
as a vigorous shortwave is slated to move through the western
Great Lakes region. Despite the lift, model soundings show a mid
level warm layer which would be a limiting factor in the
development of afternoon showers and thunderstorms. Given the
shortwave tracking through the region will at least go with a
slight chance for precipitation during the afternoon hours with
activity expected to be isolated at best given the unfavorable
soundings. Behind the cold front highs on Thursday are expected to
range from the upper 70s across the north, with around 80 expected
across central and east-central Wisconsin.

.LONG TERM...Thursday Night Through Tuesday
Issued at 331 AM CDT Wed Jul 26 2017

An upper level disturbance will drop southeast into the western
Great Lakes region on Thursday and then exit the area Thursday
night. Otherwise, a ridge across the western United States will
dominate the weather pattern with the western Great Lakes region
in a west northwest flow. The heat is expected to stay to the west
with high temperatures through much of the period at or a few
degrees above normal.

An upper level disturbance will bring a chance of showers and
thunderstorms early Thursday evening. The next chance of rain
would be on Sunday and Monday, but there is a lot of uncertainty
if this would occur. A few cool nights are in store across the
north Thursday night and again Friday night with the typical
cold spots could drop into the upper 40s. Made some adjustments
each day to reflect our typical warm spots during the day and
our typical cold spots at night.

Eckberg.
&&

.AVIATION...for 12Z TAF Issuance
Issued at 605 AM CDT Wed Jul 26 2017

A cold front will continue pushing through the cwa today. Upstream
observations and model data suggest several rounds of showers and
thunderstorms are expected today as this front slowly sinks south.
Conditions are likely to drift between VFR and MVFR as the front
moves through, with IFR cigs possible at times with heavy rain.
the rain is expected to exit from north to south later this
afternoon and this evening, with VFR cigs expected by tonight.
&&

.GRB WATCHES/WARNINGS/ADVISORIES...
Beach Hazards Statement through this evening for WIZ022-040-050.
&&

$$

SHORT TERM.....Kurimski
LONG TERM......Eckberg
AVIATION.......Kurimski



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