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Area forecast discussion 
National Weather Service Green Bay WI
637 PM CDT Tuesday Aug 4 2015

Updated aviation portion for 00z taf issuance

Short term...tonight and Wednesday
issued at 254 PM CDT Tuesday Aug 4 2015

Until Wednesday evening
quiet Summer weather expected...with the major forecast questions
being the evolution of current shower activity and temperatures...
particularly tonight's lows.

Morning/afternoon shower activity spurred by subtle shortwave
trough activity on the periphery of the upper low near James Bay
has been present again today. Compared to yesterday
is mostly contained to the Upper Peninsula...though some showers
have bled into Florence and Marinette counties. Given the lack of
southward spread...have trimmed back probability of precipitation to the border areas
through the early evening before bringing them to an end tonight.
Given trends over the past hour or so...this might even be a
conservative draw down. Though midlevel cyclonic flow will linger
a bit into tomorrow before some weak ridging works in...surface
high pressure and rising heights should clamp off potential for
any more showers tomorrow. Model guidance seems to have largely
given up on precipitation tomorrow as well.

Lingering cloudiness last night chopped off temperatures up north
before they could fall below 50 degrees...well above forecast.
Similar danger exists tonight...but it seems less of a hazard
tonight with the surface high expected in the area. As
such...largely left low forecast untouched...with only cosmetic
tweaks. Though it is not a strong signal...guidance does indicate
potential for some patchy fog tonight. Assuming clouds clear out
and temperatures fall as expected...that doesn't seem unreasonable in
north central Wisconsin.

Regardless of precipitation potential...meager instability at low levels
should allow for some fair weather clouds to develop yet again
tomorrow. Expectation would be to Blunt potential for highs
tomorrow...keeping them in a similar neighborhood as the past
couple of days for most of the area. Did tweak a couple of points
based on over/underperformance on highs today...but as with the
low forecast...changes are cosmetic.

Long term...Wednesday night through Tuesday
issued at 254 PM CDT Tuesday Aug 4 2015

The models are in better agreement today than yesterday. They now
agree that the majority of jet energy coming out of The Rockies
will stay far enough south of our area to keep dry weather in the
forecast Wednesday night and Thursday. There is also pretty good
agreement in bringing in showers and thunderstorms late Thursday
night and Friday as an upper trough moves from North Dakota to the
Great Lakes. Looks like Gulf moisture will not be available but
satellite picture show moisture coming in from the Pacific which
should be sufficient to bring some needed rains to the region.

West northwest upper flow Saturday and Sunday should allow for mainly
dry weather though the models do forecast measurable precipitation
at times. The better chance for rain looks to be late Saturday night
or early Sunday with a weak trough moving through. Temperatures should
be pretty close to normal for much of the rest of the week though
humidity levels will slowly increase.

Aviation...for 00z taf issuance
issued at 628 PM CDT Tuesday Aug 4 2015

Expect isolated showers to end around Door County before sunset...
followed by a gradual decrease in cloud cover as high pressure
arrives this evening. With partly cloudy skies and light winds
anticipated overnight...we should see some fog development.
The most significant fog (with possible LIFR vsbys) is expected in
the climatologically favored locations in north central and far
northeast Wisconsin...with patchy fog elsewhere. After the fog
dissipates early in the day...expect scattered-broken cumulus clouds to
develop during the heat of the day.


Grb watches/warnings/advisories...


Short term.....Luchs
long term......rdm

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