Area Forecast Discussion
Issued by NWS Green Bay, WI

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FXUS63 KGRB 201943
AFDGRB

Area Forecast Discussion
National Weather Service Green Bay WI
243 PM CDT MON JUN 20 2016

Forecast discussion for routine afternoon forecast issuance

.SHORT TERM...Tonight and Tuesday
Issued at 242 PM CDT Mon Jun 20 2016

The latest RAP analysis and satellite/radar imagery show a cold
front sliding south across lower Michigan and northern Illinois.
Behind the front, winds shifted to the northwest and became gusty by
late this morning, with a few gusts reaching up to 30 kts. Though
some cu moved into north-central WI early this afternoon, dewpoints
have dropped rapidly into the 40s and 50s behind the front.  Looking
upstream, skies are mostly clear over the northern Plains thanks to
surface high pressure settling southward.  Forecast concerns revolve
around sky and temps trends.

Tonight...Todays cold front will settle over the Ohio Valley to mid-
Mississippi Valley by late tonight.  North of the front, the western
Great Lakes will be situated beneath northwest flow aloft, and under
the influence of weak surface high pressure centered over the
northern Plains.  As the pressure gradient slackens and mixing
ceases, should see winds and wind gusts diminish this evening. Clear
to mostly clear conditions should prevail until late, when a
shortwave moving into Lake Superior could push scattered clouds into
north-central WI.  Cooler temps ranging through the 50s.

Tuesday...Shortwave troughs will continue to swing across the
northern Great Lakes, and the higher res models show a weak surface
trough dropping south across northern and central WI from late
morning through the afternoon.  Should see some enhanced rather high-
based cu form along the trough, aided by steep low level lapse
rates.  Most higher res guidance is dry however, due to mid-level
capping at around 700mb.  So will keep a dry forecast.  Highs
ranging from the lower 70s north to near 80 south.

.LONG TERM...Tuesday Night Through Monday
Issued at 242 PM CDT Mon Jun 20 2016

The main fcst concerns will include two potentially significant
periods of rainfall; Wednesday into Wednesday night, and Saturday
into Saturday night.

Dry weather should persist through Tuesday night, but low pressure
approaching from the Northern Plains will lift a warm front to
near the WI/IL border Wednesday into Wednesday night. Developing
WAA/Isent lift, combined with a surge of moisture (PWATs 1.5+
inches) and elevated instability into at least central and east
central WI, will lead to increased pcpn chances. Have increased
pops from the previous fcst, especially during the afternoon and
evening.

The pcpn should taper off by Thursday morning as high pressure
builds into the western Great Lakes. The high will bring dry
conditions through at least Friday, along with seasonable
temperatures. Return flow may bring a chance of elevated tstms
Friday night, especially over our northwest counties.

A 35-45 kt LLJ will develop in advance of a cold front Saturday
afternoon and evening, resulting in another surge of significant
moisture and instability. Have increased pops to likely on
Saturday night, when the cold front moves through. Heavy rainfall
is possible. Most of the pcpn should come to an end as the front
exits east central WI early Sunday morning.
&&

.AVIATION...for 18Z TAF Issuance
Issued at 1154 AM CDT Mon Jun 20 2016

Gusty west winds up to 30 knots will veer slightly to
the northwest this afternoon.  Gusts will remain persistent through
early this evening before diminishing.  Then quiet weather for the
rest of the taf period.  Northwest winds will become gusty again
late Tuesday morning, but not quite as gusty as today.  There should
also be a little more in the way of clouds tomorrow, around 5-6 kft.
&&

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

$$

SHORT TERM.....MPC
LONG TERM......Kieckbusch
AVIATION.......MPC



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