Area Forecast Discussion
Issued by NWS Green Bay, WI

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000
FXUS63 KGRB 142351
AFDGRB

Area Forecast Discussion
National Weather Service Green Bay WI
551 PM CST Tue Feb 14 2017

Updated aviation portion for 00Z TAF issuance

.SHORT TERM...Tonight and Wednesday
Issued at 235 PM CST Tue Feb 14 2017

The primary forecast challenges to be precipitation trends into
this evening accompanying a cold front and then amount of lake
effect snow showers across north-central WI tonight into Wednesday
morning.

The 20z MSAS surface analysis showed an area of low pressure over
southeast Ontario with a cold front extended southwest through
central WI into northern IA. High pressure stretched from central
Canada southward into the central Plains. The radar mosaic
indicated several bands of precipitation along and behind the cold
front with visibilities briefly getting knocked down to under 2
miles in heavier (albeit very brief) snow squalls.

Northeast WI to reside on the cold, cyclonic side of an exiting
shortwave trough tonight with a colder/blustery air mass taking
over for the overnight hours. The CAA, coupled with favorable
trajectories, should be able to produce some lake effect snow
showers/flurries over north-central WI tonight. Accumulations
appear to be minimal due to low inversion heights and delta-T
values only in the middle teens. Perhaps up to an inch of snow
possible over the Vilas County snowbelt with less than one-half
inch expected farther south and east. Min temperatures to range
from 10 to 15 above north-central, to the lower 20s east-central
WI.

The lake effect snow threat will continue through at least
Wednesday morning before the cyclonic flow weakens and winds begin
to back to the west-northwest, making trajectories become
marginal. Do not anticipate much more than a couple tenths of an
inch of accumulation over the Vilas County snowbelt. Otherwise,
the rest of northeast WI is expected to be dry, but mostly cloudy
as mid/high clouds overspread the region as some warmer air aloft
moves toward WI. Max temperatures will be noticeably colder than
previous days behind the departed cold front. Look for readings to
be closer to normal with lower to middle 20s north, mainly 25 to
30 degree range south.

.LONG TERM...Wednesday Night Through Tuesday
Issued at 235 PM CST Tue Feb 14 2017

Dry and mild weather weather expected through Sunday,
as a large upper ridge approaches from the Plains. Highs should
approach or exceed 50F in some areas Saturday, Sunday and Monday.

Dewpoints should stay below freezing through Saturday or Sunday,
so not expecting low clouds or fog until they do. This will also
slow snowmelt and river rises.

An upper trough lifting northeast from the northern Plains into
Canada and an approaching surface cold front will bring south
winds and Gulf moisture to the region Monday afternoon and night
along with a good chance of rain. The rain and high dewpoints will
likely produce fog and rapid melting of whatever snow is left on
the ground. This could cause rising rivers and ice jams in some
areas.
&&

.AVIATION...for 00Z TAF Issuance
Issued at 546 PM CST Tue Feb 14 2017

A cold front and upper level trough will be exit the southeast
part of the forecast area at the start of the TAF period, and
take any lingering snow showers with it. The exception will be in
north central WI, where lake effect snow showers will persist
into Wed morning. The remainder of the region is forecast to be
dry tonight into Wednesday. Mainly VFR conditions are expected,
however as the colder air sets up over WI, cloud bases may drop
into the MVFR range late tonight into Wednesday morning across
northern and central WI.
&&

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

$$

SHORT TERM.....Kallas
LONG TERM......RDM
AVIATION.......Kieckbusch



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