Area Forecast Discussion
Issued by NWS Green Bay, WI

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FXUS63 KGRB 230823
AFDGRB

Area Forecast Discussion
National Weather Service Green Bay WI
323 AM CDT TUE AUG 23 2016

Forecast discussion for routine morning forecast issuance

.SYNOPSIS...
Issued at 321 AM CDT Tue Aug 23 2016

Warm and more humid today, then some rain tonight into Wednesday.

The large scale pattern will be anchored by near full latitude
ridging over the eastern Pacific, and flatter ridging over the
southeastern CONUS. In between, a positively tilted trough will be
positioned from Hudson Bay to the northern Rockies. The southern
portion of the trough will shift westward late in the period, as
the eastern Pacific ridge edges back to the west a bit.

Temperatures will be modestly above normal for the next few days,
drop back to near or a little below normal for the end of the
work week and the start of the upcoming weekend, then return to a
little above normal for early next week. Normal precipitation for
a week at this time of year is about 3/4 inch. Given that two major
shortwaves are expected to cross the area along with some smaller
scale features, the best estimate is that precipitation amounts
will end up near normal. But the convective nature of the
precipitation will likely result in considerable variability
across the area.
&&

.SHORT TERM...Today...Tonight...and Wednesday
Issued at 321 AM CDT Tue Aug 23 2016

The persistent cluster of convection over far northeast Wisconsin
appears to finally be exiting the area. The rather sharp shortwave
ridge that will cross the area today should promote subsidence, so
stuck with dry forecast.

A shortwave from the central Plains will approach the area this
evening. It should cross the area tonight, ahead of more
substantial trough translating east across southern Canada and the
northern CONUS. Pretty much each model offered a somewhat
different idea of how the precipitation with the shortwave will
evolve as it approaches and crosses the area. Overall, trended the
forecast toward the ECMWF. But was a little concerned that both
hi-res WRFs showed coverage becoming more scattered late tonight
and early Wednesday. For that reason, did not take PoPs beyond the
likely category since it is possible coverage may not be total as
the convection comes through the area. Tapered PoPs down more
quickly Wednesday than in previous forecasts. Although some
precipitation may linger, it would probably only be isolated or
scattered as there is likely to be some subsidence behind the
departing shortwave lingering across the area as the surface front
crosses the region.

.LONG TERM...Wednesday Night Through Monday
Issued at 321 AM CDT Tue Aug 23 2016

Model solutions still vary regarding the departure of the
upcoming system, so just kept some thunder in the southeast half
of the forecast area during the evening, and just a slight chance
for showers in east central Wisconsin the rest of the night.

Looks like there is better agreement on a period of dry weather
under surface high pressure from Thursday through Friday night
before timing differences return. The ECMWF looks to be the
fastest with QPF ahead of the next system, while the Canadian kept
the entire area dry on Saturday. Due to these timing differences the
initial model blend for Friday through Monday has been left
alone. This resulted in a chance for showers and storms in central
and north central Wisconsin on Saturday, and across the entire
area Saturday night through Monday.

In general, the dry days will be cooler (i.e. close to normal),
while the wet days reach highs several degrees above normal.
&&

.AVIATION...for 12Z TAF Issuance
Issued at 321 AM CDT Tue Aug 23 2016

Low-level wind shear will dissipate this morning as the flow
above the surface weakens. Otherwise, expect primarily good flight
conditions during the day, with the possible exception of some
gusty surface winds. Flight conditions will likely deteriorate
after midnight as precipitation spreads across the area.
&&

.GRB WATCHES/WARNINGS/ADVISORIES...
Beach Hazards Statement from 7 AM CDT this morning through
Wednesday evening FOR WIZ022-040-050.
&&

$$

SYNOPSIS.......Skowronski
SHORT TERM.....Skowronski
LONG TERM......MG
AVIATION.......Skowronski



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