Area Forecast Discussion
Issued by NWS Green Bay, WI

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FXUS63 KGRB 180747
AFDGRB

Area Forecast Discussion
National Weather Service Green Bay WI
247 AM CDT Sat Mar 18 2017

Forecast discussion for routine morning forecast issuance

.SHORT TERM...Today...Tonight...and Sunday
Issued at 247 AM CDT Sat Mar 18 2017

A mid level PV anomaly, clearly visible on the mid and upper level
GOES-R water vapor imagery, will track through the western Great
Lakes early this morning. This will bring a mix of snow, light
rain and freezing drizzle to northeast Wisconsin until it tracks
east of the area in the next few hours. The line between liquid
and ice crystals appears to be a bit deeper moisture out to the
west where moisture rises above the -10 celsius line. This line is
expected to track east through the morning before the
precipitation ends. However given the limited moisture the impact
from this wintry mix is expected to be fairly minimal, therefore
no headlines are anticipated at this time. After the PV anomaly
tracks east and precipitation ends, Lake Effect precipitation will
continue through the morning hours before ending around noon as
winds become light and drier, warmer air advects in from the west
ending the Lake Effect component. Snowfall totals across north
central Wisconsin are expected to be fairly minimal, with a few
tenths of an inch possible this morning before ending.

Once this system tracks east a dry period will exist across the
western Great Lakes tonight into most of Sunday as a ridge of high
pressure tracks through the area. A weak PV anomaly could bring a
slight chance for rain across north central Wisconsin Sunday
afternoon. Given the limited moisture and fairly weak nature of
this feature POPs will be fairly small.

Temperatures this weekend will warm as highs Today are expected
to top out from the lower to middle 30s across the north, with
lower 40s across the south. The warming trend continues into
Sunday with highs in the middle to upper 40s as 50 degrees is
possible across portions of central Wisconsin.

.LONG TERM...Sunday Night Through Friday
Issued at 247 AM CDT Sat Mar 18 2017

Forecast concerns in this period revolve around precip chances
Sunday night into Monday, and also late in the week.  Have a
preference for the ecmwf based upon model/ensemble mean comparisons.

Sunday night through Monday night...A cold front will slide east
from Minnesota to eastern WI during Sunday night.  Ahead of the
front, low level moisture below 750mb continues to look more robust
than moisture above this level, but still looks to be sufficient for
precip chances.  Amounts should be light, however, due to this lack
of moisture, and also subsidence in the right front quad of a jet
streak. Will show the highest chances late in the evening and early
overnight across the east.  Behind the front, mid and high clouds
will linger through much of Monday, but dry low level air emanating
from a ridge of high pressure will arrive late Sunday night over
north-central WI and on Monday morning over eastern WI, thereby
ending precip chances.  Skies finally clear on Monday night with
strengthening cold advection and breezy northwest winds.

Rest of the forecast...Canadian high pressure will hang around the
region from Tuesday through Wednesday night.  Minor lake effect snow
showers could impact the snow belts of Vilas county for parts of
this time period, but the airmass will be quite dry, so not
expecting any significant accums.  The next chance of widespread
precip will occur Thursday through next Saturday with the passage of
a cyclone.  Some wintry precip appears possible on Thursday into
Friday morning with a chilly airmass in place.  Pending the track of
the low, a transition to rain appears likely at least over eastern
WI as warmer air arrives on Friday and Friday night.
&&

.AVIATION...for 06Z TAF Issuance
Issued at 1155 PM CDT Fri Mar 17 2017

Radar loop showed some showers moving across Wisconsin as
surfaces and 500mb lows were passing through far northern
Wisconsin/Upper Michigan. Ceilings were mainly IFR in the north
and MVFR (and scattered VFR) in central and east central
Wisconsin. Visibilities were VFR across central Wisconsin, except
in precipitation, and MVFR/IFR farther east and north. As a cold
front moves through the state and winds increase, visibilities
should increase as well. Expect plenty of MVFR and IFR ceilings
throughout the night before moisture becomes more shallow during
the day on Saturday and clouds start to break up. Lake effect snow
showers in the far north will result in MVFR conditions at times.
&&

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

$$

SHORT TERM.....Kurimski
LONG TERM......MPC
AVIATION.......MG



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