Area Forecast Discussion
Issued by NWS Green Bay, WI

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FXUS63 KGRB 131909

Area Forecast Discussion
National Weather Service Green Bay WI
209 PM CDT Sun Aug 13 2017

Forecast discussion for routine afternoon forecast issuance

.SHORT TERM...Tonight and Monday
Issued at 208 PM CDT Sun Aug 13 2017

The latest rap analysis and satellite/radar imagery show upper level
low pressure spinning over the eastern Dakotas and western Minnesota
early this afternoon.  Showers and storms continue to develop ahead
of the low, but remain mainly west of the MN/WI border.  Some decent
cu has popped over north-central WI, and could see an isolated
shower develop over Vilas County later this afternoon into early
this evening.  As low pressure moves closer to the region, precip
chances and trends are the main forecast concerns.

Tonight...The shortwave trough will slowly move east across the
northern Mississippi Valley.  With mid 50s dewpoints all the way
south into northern Missouri and central Illinois, moisture will
take some time to move into the region.  As a result, will see
increasing clouds above 8-9kft from west to east tonight, but precip
chances are likely to hold off until after 09z tonight across
central and north-central WI.  More clouds will call for warmer
lows, with temps ranging through the 50s.

Monday...The shortwave trough finally moves into the state and will
see the threat of precip increase from west to east through the day.
Slowed down the timing slightly from the previous forecast, as
indicated by the mesomodels.  Will see better mid-level moisture
transport and weak instability develop in the afternoon, so no
reason to downgrade the chance of thunder. Due to the slower arrival
time, will increase temps a degree or two over the east.

.LONG TERM...Monday Night Through Sunday
Issued at 208 PM CDT Sun Aug 13 2017

Low amplitude flow aloft should prevail across the northern CONUS
during this part of the forecast, with several shortwave trofs
moving through the region.

Monday`s precipitation will linger into the evening. Weak shortwave
ridging will dry things out until Wednesday when approaching shortwave
trof and associated surface system brings chance for showers/storms
to the area. ECMWF has been a bit weaker/faster than GFS with
system, resulting in less QPF/deep convection for NE Wisconsin.
Will continue blend of models until we get closer to mid-week.

Another mid level trough will bring chances for showers late in
the week.

Temperatures should generally be near or a bit above normal.

.AVIATION...for 18Z TAF Issuance
Issued at 1050 AM CDT Sun Aug 13 2017

Lingering dry air at low-levels will probably keep ceilings and
vsbys vfr over the period. But clouds will be on the increase as
a storm system moves in from the west tonight into Monday. Chance
of light rain will slowly ramp up from late tonight through the
end of the taf period.



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