Scientific Forecaster Discussion

Return to Local Conditions & Forecast

Without Abbreviations
With Abbreviations

Area forecast discussion 
National Weather Service Green Bay WI
956 PM CDT Tuesday Oct 21 2014

Updated aviation portion for 06z taf issuance

Short term...tonight and Wednesday
issued at 255 PM CDT Tuesday Oct 21 2014

Cloud trends and temperatures are the main concerns during this
part of the forecast.

Surface high pressure will remain over most of the Great Lakes
region overnight as a middle level trough moves to central Wisconsin
by 12z Wednesday. Would expect mostly clear/partly cloudy
conditions across the forecast area overnight with light or calm
winds. Have patchy fog from about 09z to 12z since there was some in
Minnesota under the high late last night/early this morning. 12z
NAM MOS looked a bit too warm so either split the difference or
went with the colder 12z GFS MOS for overnight lows. Expect lows
in the middle 20s to around 30 for much of the area...but a little
warmer from the Fox Valley east to Lake Michigan.

The surface high and middle level trough will slowly make their way
to the east during the day on Wednesday. Looks like mainly high
clouds moving into the area during the day so there should still
be plenty of sunshine. Weak southeast surface flow will allow for
warmer temperatures than today at inland locations...highs near
the lake should be similar to highs today.

Long term...Wednesday night through Tuesday
issued at 255 PM CDT Tuesday Oct 21 2014

Precipitation trends Wednesday night through Thursday night...and temperatures
through the entire period...will be the main forecast concerns.

An upper level trough and associated moisture band (pwats of 1+ inch)
will bring showers to the region from late Wednesday night through Thursday evg.
Have sped up the timing a little to match the latest model concensus...
and increased probability of precipitation a bit on Thursday and Thursday evg.

West-northwest zonal flow will set up over the area from Friday through Sat night...
along with an accompanying warming trend. High temperatures should reach the
lower to middle 60s.

SW flow aloft will set up on Sunday as a broad upper trough moves across
The Rockies. Dry condiitons should prevail over c/NE WI...with mild
temperatures in the 60s continuing.

Low pressure is expected to track northwest of the region into Ontario on
Sunday night and Monday...with a weak front moving through WI. A
second surface low may develop along the slow moving boundary on Monday night
or Tuesday...as the sharpening upper trough approaches the western
Great Lakes. The GFS is most aggressive with this scenario...and
brings a deepening low through NE WI on Tuesday morning. Given
significant models differences during this period...have stayed
close to the preferred model blend for probability of precipitation...with only slight
chance/chance probability of precipitation warranted for now. Mild temperatures should continue
through Monday...though much cooler air is poised to arrive by
Tuesday.
&&

Aviation...for 06z taf issuance
issued at 955 PM CDT Tuesday Oct 21 2014

With the exception of patchy MVFR fog between 09z and 13z...VFR
conditions will prevail tonight into Wednesday.
&&

Grb watches/warnings/advisories...
none.
&&

$$

Short term.....Mg
long term......kieckbusch
aviation.......tdh

National Weather Service Glossary of Abbreviations