Area Forecast Discussion
Issued by NWS Green Bay, WI

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759
FXUS63 KGRB 271914
AFDGRB

Area Forecast Discussion
National Weather Service Green Bay WI
214 PM CDT FRI MAY 27 2016

Forecast discussion for routine afternoon forecast issuance

.SHORT TERM...Tonight and Saturday
Issued at 213 PM CDT Fri May 27 2016

The latest rap analysis and satellite/radar imagery show a large
upper trough positioned over the Kansas/Colorado border.  Embedded
shortwaves in the southwest flow ahead of this upper trough continue
to move northeast over the central and northern Mississippi Valley,
and produce clusters of showers and storms.  Additional focus is
being provided by a surface trough/warm front that extends from
Minneapolis to Sheboygan.  Though coverage of showers/storms have
been isolated to scattered, expectations are for coverage to
increase later this afternoon as a shortwave from northeast Iowa
lifts across the state.  Precip trends and the possibility of severe
weather are the main forecast concerns.

Tonight...Convergence along the surface trough/warm front will lift
northward across central and northern Wisconsin this evening.  At
the same time, weak shortwave impulses will be sliding northward
over the state.  Appears like a good opportunity for rainfall at all
locations, but placed the highest chances generally over eastern
Wisconsin where low level convergence is maximized and pwats are the
highest. Once that surface trough clears the U.P border shortly
after 06z, precip chances look to subside some.  Any severe threat
is rather low due to meager instability, but locally heavy rainfall
is possible with pwats peaking between 1.75-2.00 inches.  Lows
mostly in the low to mid 60s.

Saturday...As the upper trough moves across the central plains,
southwest flow will continue aloft.  Models track another shortwave
across the region during the morning hours.  So after a possible
lull in the coverage of precip overnight, will increase precip
chances again during the AM hours.  Though chances of precip look
best across the north during the afternoon, daytime instability will
allow for chances occurring over central and east-central too.  A
few strong storms and locally heavy rainfall cannot be ruled out,
but severe weather is unlikely due to limited instability.  Highs
mainly in the mid to upper 70s. Some cooler locations are likely
where rainfall is most persistent.

.LONG TERM...Saturday Night Through Friday
Issued at 213 PM CDT Fri May 27 2016

Southwest upper flow aloft will continue into Sunday as a short
wave trough from the Northern Plains drifts over the Western Great
Lakes. Moist southerly flow will continue to support showers and
storms through Sunday until the trough departs to the east Sunday
evening. This trough will be associated with a cold front passing
over the state Sunday for a likely focus of convection.

Subtle upper height increases with weak ridging will build into
the area later Sunday night into most of Monday night for an
overall brief drier stretch of weather. This upper ridge was ahead
of a Pacific Northwest upper trough gradually working into the
Northern Plains. Will go with the drier trend for Monday at this
time...but some progs indicate weak low pressure lingers over far
northeast Wisconsin and Upper Michigan Monday for a possible
focus of afternoon convection.

Progs remain consistent with a return to more chances of rain
Tuesday into Thursday as the Northern Plains upper trough works
into the Western Great Lakes region. Warm more moist air will
return north again with pcpn chances spreading back northward.
Progs divert on the timing of a cold front passage mid week.
ECMWF a bit quicker with the front wednesday along with an dry
slot. The GFS delays the cold front more toward Thursday.
&&

.AVIATION...for 18Z TAF Issuance
Issued at 1148 AM CDT Fri May 27 2016

PERIODS OF SHOWERS AND SCT WILL LIFT NORTH INTO THE REGION AS A
WARM FRONT, CURRENTLY OVER SOUTHERN WISCONSIN, MOVES ACROSS THE
REGION. ONE CLUSTER OF STORMS WILL IMPACT GREEN BAY AND NORTHEAST
WISCONSIN EARLY THIS AFTERNOON, BUT ACCURATELY TIMING SUBSEQUENT
PERIODS OF SHOWERS WILL BE A REAL PROBLEM. EXPECT MAINLY VFR
CONDITIONS DURING THE DAY, WITH FLIGHT CONDITIONS GRADUALLY
DETERIORATING TO IFR AND PATCHY LIFR OVERNIGHT. CONFIDENCE IN THE
TIMING AND OCCURRENCE OF TSTMS WAS TOO LOW TO MENTION IN THE TAFS
RIGHT NOW.
&&

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

$$

SHORT TERM.....MPC
LONG TERM......TDH
AVIATION.......MPC



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