960
FXUS63 KMQT 211938
AFDMQT

Area Forecast Discussion
National Weather Service Marquette MI
238 PM EST Fri Feb 21 2025

.KEY MESSAGES...

- Very low chances for precipitation this weekend (20% or less) with
  perhaps better chances for mixed precipitation Sunday night into
  Monday, although model uncertainty is great.

- Looking milder this weekend into the first half of next week with
  periods of above freezing temperatures likely. Models then trend to
  near or below normal for the end of next week (Thursday-Friday).

&&

.SHORT TERM /THROUGH TONIGHT/...
Issued at 237 PM EST Fri Feb 21 2025

Water vapor imagery and RAP analysis show nw flow into the Great
Lakes region this aftn. A well-defined shortwave embedded in this
flow is just n of the MN/ON border. WAA/isentropic ascent in
response to this feature strengthens with height and maximizes and
is strong at around 500mb which is roughly the base of the
widespread high cloudiness that has spread across Upper MI today.
Despite the vigorous nature of the shortwave and fairly strong
forcing per deep layer q-vectors, the lack of moisture at low-levels
is preventing any pcpn development. Only some mid-level cloudiness
around 7kft is noted in ne MN where deep layer forcing is currently
maximized. Temps this aftn have risen into the 20s F across the
board despite the fairly thick cloud high cloudiness.

Aforementioned upstream shortwave will begin weakening as it tracks
across Lake Superior/Upper MI this evening. Low-level air mass will
remain too dry to support any pcpn development. However, late in the
night, weak sfc trof moving over the lake and the resulting
convergence underneath 850mb temps of -10C might be sufficient for
-shsn to develop into Keweenaw County right along the convergence
zone. Only a 15-30pct chc of pcpn is warranted. With cloudiness
thinning out, a wide range of temps is possible tonight, dependent
on where winds fully decouple. Traditional interior cold spots that
normally decouple should see temps fall toward 5F above. Temps will
range up to 15F or so, mainly w to n central high terrain down to
Lake Superior as winds will remain stirring and may be gusty.

&&

.LONG TERM /SATURDAY THROUGH THURSDAY/...
Issued at 153 PM EST Fri Feb 21 2025

Upper air pattern consists of a shortwave in the desert sw, a
shortwave in the mid Mississippi Valley and one in New England 12z
Sat. Ridging builds into the western U.S. 12z Sun. A shortwave near
Lake Winnipeg 00z Mon passes north of the upper Great Lakes Mon
morning. Area gets sideswiped with some lake effect pcpn in west
wind lake effect snow showers across the far north and east on
Saturday into Saturday night and then Sunday looks dry. There is a
chance for some mixed light pcpn Sunday night with some freezing
rain, snow and rain possible.

In the extended, the GFS and ECMWF show a broad 500 mb ridge across
Mexico, a trough in the lower Great Lakes and another in the Pacific
NW 12z Tue. A shortwave will move into the upper Great Lakes 12z
Wed. By 12z Thu, a strong ridge is in the western U.S. Upper air
pattern amplifies 12z Fri with the strong ridge in the western U.S.
and a deep trough in the east. Temperatures go from above normal on
Tue and Wed to below normal Thu and near normal on Fri. More mixed
pcpn is possible Monday night and again for Wednesday.

&&

.AVIATION /18Z TAFS THROUGH 18Z SATURDAY/...
Issued at 1249 PM EST Fri Feb 21 2025

Low-levels will remain relatively dry thru Sat morning, allowing VFR
to prevail at IWD/SAW thru this fcst period. At CMX, sw winds will
veer a little tonight, resulting in sufficient overlake trajectory
for lake stratocu (MVFR cigs) to develop at some point overnight.
Increasing winds overtop stable sfc-based layer tonight will also
result in low-level wind profile approaching LLWS criteria at
IWD/SAW. Later fcsts will reassess that potential.

&&

.MARINE...
Issued at 153 PM EST Fri Feb 21 2025

Southwest gales to 35 knots are expected tonight across the west
half of Lake Superior and gale warning still looks good. West winds
of 20 to 30 knots are expected on Saturday before winds diminish
below 20 kt Saturday night into Sunday as a weak trough pushes in
from the north. Southerly winds increase slightly to 20-25 kt Sun
night ahead of the next approaching clipper system, highest over the
east half. After that though, winds generally remain 20 kt or less
Monday into Wednesday under weak high pressure.

&&

.MQT WATCHES/WARNINGS/ADVISORIES...
Upper Michigan...
None.
Lake Superior...
  Gale Warning from 7 PM this evening to 1 AM EST Saturday for
     LSZ263-264.

Lake Michigan...
None.

&&

$$

SHORT TERM...Rolfson
LONG TERM...07
AVIATION...Rolfson
MARINE...07