Area Forecast Discussion
Issued by NWS Green Bay, WI

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FXUS63 KGRB 201021

Area Forecast Discussion
National Weather Service Green Bay WI
521 AM CDT FRI MAY 20 2016

Updated aviation portion for 12Z TAF issuance

.SHORT TERM...Today...Tonight...and Saturday
Issued at 304 AM CDT Fri May 20 2016

A weak upper low pressure trough will slowly drift over the Mid and
Upper Midwest and western Great Lakes Region today into Saturday.
Main energy and precipitation with this system to be focused over
the Mid Mississippi region. Dry surface to 850 high pressure ridge
remains settled over the area today and into the weekend for the
continued dry weather.

Some return moisture on the backside of the surface high may work
into the western two thirds of the state to produce a period of
diurnal cu this afternoon. A period of high base sct-bkn cu
expected. The GFS run continues to produce some light
precipitation in the return flow over Northwest Wisconsin
today...with a band of 0.10 across far Northern Wisconsin into
much of Upper Michigan. Some merit to this band of precipitation
due to weak convergence setting up along a weak boundary across
the Northern Great Lakes region. Total total values near 50 this
afternoon at IWD along with some small cape, but the dry air mass
has been too dominate lately.

This weak boundary drops south over the area late tonight into
early saturday in response to a stronger ridge developing to the
west this weekend. likely result of the front will be a wind shift
to the north or northwest but continued dry Saturday.

.LONG TERM...Saturday Night Through Thursday
Issued at 304 AM CDT Fri May 20 2016

Above normal temperatures are expected to prevail through the
early part of next week. Fire danger is a concern with conditions
remaining dry through at least Sunday night. Showers and
thunderstorms are possible in central and north central Wisconsin
on Monday, mainly during the afternoon, in increasingly unstable
air ahead of an upstream mid level short wave and an approaching
surface front. Rain chances expand across the entire area Monday

The front will move into Wisconsin on Tuesday and a surface low
is forecast to entire the state on Wednesday, continuing to move
northeast through Thursday. A series of short waves in the mid
level flow will combine with the surface features to keep a chance
for showers and storms across the area through Thursday.

Temperatures should be slightly below normal by Thursday with the
rain and arrival of the front.

.AVIATION...for 12Z TAF Issuance
Issued at 521 AM CDT Fri May 20 2016

VFR conditions to continue today and tonight. Diurnal cu in the
6K-8Kft range expected to develop late this morning into the
afternoon then dissipating this evening. A weak front dropping
southward overnight will turns winds northwest...but still winds
will be on the lighter side.

Issued at 304 AM CDT Fri May 20 2016

Winds overall are expected to remain less than 10 kts today into
this weekend. A weak front will drop over the marine waters
tonight shifting winds from light south to north 5 to 10 kts.

Issued at 304 AM CDT Fri May 20 2016

Mixing and dry boundary level conditions will continue to produce
afternoon relative humidity levels in the lower to mid 20s across
much of the area today into this weekend. Lowest humidity levels
expected over sand regions and over far Northeast Wisconsin. A
weak front will drop south over the area late tonight into early
Saturday. The front is expected to be dry with only a wind shift
to the north or northwest marking the passage.



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