Area Forecast Discussion
Issued by NWS Green Bay, WI

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FXUS63 KGRB 251705
AFDGRB

Area Forecast Discussion
National Weather Service Green Bay WI
1205 PM CDT MON JUL 25 2016

Updated aviation portion for 18Z TAF issuance

.SYNOPSIS...
Issued at 318 AM CDT Mon Jul 25 2016

Not as humid today, but still quite warm. More humid again with
some showers and thunderstorms mid-week.

Low amplitude band of westerlies along the U.S./Canadian border
will sag south into the eastern U.S. the next several days in
response to upper anticyclone within the subtropical ridge
consolidating back over the Desert Southwest. The result will be
west-northwesterly upper flow over the forecast area. The pattern
is likely to become somewhat progressive late in the period.

Still quite warm today, but with humidities considerably lower
than yesterday. Very warm and more humid mid-week...then
temperatures and humidities will drop back down to more typical
late-July levels for the end of the week and upcoming weekend.
Most locations will get some precipitation, but amounts are tough
to gauge, and will depend heavily on the track of shortwave
heading into the eastern CONUS upper trough mid-week.
&&

.SHORT TERM...Today...Tonight...and Tuesday
Issued at 318 AM CDT Mon Jul 25 2016

Quieter weather today and tonight as weak high pressure crosses
the area. Light winds tonight may allow for some patchy fog to
form, so added that to the grids for the late night hours.

Moisture will increase again Tuesday as the return flow on the
back side of the high spreads across the area. The best moisture
transport will be across the north. Interestingly enough, the
majority of the models actually generated the most precipitation
over northeast Wisconsin, possibly due to additional storms
developing in the convergence zone of the double lake breeze off
Lakes Michigan and Superior. Increased PoPs a bit across the
north, but held onto dry forecast south of Highway 29.

Temperatures were based on a blend of top performing guidance
products, with some adjustment for local effects.

.LONG TERM...Tuesday Night Through Sunday
Issued at 318 AM CDT Mon Jul 25 2016

A transition from rather flat upper level flow to a slightly more
amplified pattern, with a trough over the Great Lakes/Ohio
Valley, occurs during the long term forecast period. As a result
of this, and the presence of a frontal boundary in the region,
there are plenty of chances for showers and thunderstorms during
the latter half of the work week. The trough should start to make
its way eastward late in the week, so it looks like drier weather
is in store for the weekend. High temperatures should be within a
few degrees of normal Wednesday through Sunday.

Models were not the most consistent with the onset of rain,
showing some noticeable differences in their QPF fields Tuesday
night, but it looks like the chance for showers and storms will
be greatest from Wednesday through Thursday with the approaching
upper level short wave and surface cold front.
&&

.AVIATION...for 18Z TAF Issuance
Issued at 1204 PM CDT Mon Jul 25 2016

VFR conditions are expected for the next 24 hours as a weak area
of high pressure slides across southern sections of the Great
Lakes. Expect the current cu field in the 4-5K ft range to prevail
until around 00z Tue with mostly clear skies and light winds for
tonight. Some patchy fog could develop late tonight which would
lower vsbys into the MVFR range. As the high pressure starts to
pull farther to the east on Tuesday a return flow will bring
warmer, more humid conditions back to northeast WI with late
morning cu field developing once again. A cold front is forecast
to sag south into Lake Superior Tuesday afternoon and will bring a
chance of showers and thunderstorms to the RHI TAF site.
&&

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

$$

SYNOPSIS.......Skowronski
SHORT TERM.....Skowronski
LONG TERM......MG
AVIATION.......AK



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