Area Forecast Discussion
Issued by NWS Green Bay, WI

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FXUS63 KGRB 190341

Area Forecast Discussion
National Weather Service Green Bay WI
1041 PM CDT Sat Mar 18 2017

Updated aviation portion for 06Z TAF issuance

.SHORT TERM...Tonight and Sunday
Issued at 219 PM CDT Sat Mar 18 2017

Low clouds lingered across the region this afternoon. Temperatures
ranged the upper 20s across the far north to the lower 40s across
east-central Wisconsin. For the remainder of the afternoon into
this evening, most of the low clouds should dissipate around
sunset or shortly after. Later tonight, mid and high clouds will
move into the area later tonight into Sunday morning.

On Sunday, increasing south winds are expected ahead of a cold
front. Most of the rain should hold off until evening. However,
the gfs model was more aggressive with scattered showers during
the afternoon across the north. Have spread small chances of rain
eastward to account for this scenario. Models do indicate
moderately steep mid level lapse rates around 7.5 c/km, thus could
not rule out an isolated thunderstorm Sunday afternoon. Will let
midnight shift decide to add thunder to the forecast.

.LONG TERM...Sunday Night Through Saturday
Issued at 219 PM CDT Sat Mar 18 2017

Forecast concerns in this period revolve around precip chances
Sunday night into early Monday with better chance late in the

Early in period...A cold front will slide east from MN to eastern
WI Sunday night. Ahead of the front, low level moisture
sufficient for scattered showers. Steep lapse rates may be enough
for isolated thunder, but better chances south.

Skies clear Monday night with strengthening cold advection post
frontal passage.

Mid week...Canadian high pressure will hang around the region
from Tuesday through Wednesday night. Temps on Wednesday AM quite
cold with Canadian high centered over Lake Superior. Minor lake
effect snow showers could impact the snow belt of Vilas County
for parts of this time period, but the airmass will be quite dry,
so not expecting any accumulation.

Later in the week...The next chance of widespread precip will
occur late Thursday through next Saturday with strong shortwave
trof and associated low pressure system. Significant differences
in 18/12Z ECMWF (slower and much farther south) and GFS (faster
and north). Canadian model is closer to the ECMWF. Plenty of time
to work out details. Regardless, gulf moisture should be
plentiful. Some wintry precip expected Thursday night into Friday
morning with initially cold air mass in place, but transition to
rain/mix likely across most of the forecast area.

.AVIATION...for 06Z TAF Issuance
Issued at 1033 PM CDT Sat Mar 18 2017

Stratocumulus clouds have broken up in spots, but were still
holding tough in other locations. The general trend has been to
linger low clouds longer than the models suggest, so will keep
some MVFR and local IFR (at RHI) ceilings for several more hours
before scattering them out. Increasing high clouds will arrive
later tonight and Sunday morning. South winds will pick up Sunday
afternoon, with gusts to 15 to 20 kts expected.

A strong low-level jet will take aim on north central WI late
tomorrow afternoon, and may cause scattered showers to develop.
The chance of showers will continue through the evening as a cold
front arrives. There could even be a few rumbles of thunder across
parts of central and east central WI, but confidence is not high
enough to include in the TAFs.

Some borderline LLWS is expected at the TAF sites, especially
Sunday evening.



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