Area Forecast Discussion Issued by NWS Marquette, MI
000
FXUS63 KMQT 190526
AFDMQT
Area Forecast Discussion
National Weather Service Marquette MI
126 AM EDT Tue Mar 19 2024
.KEY MESSAGES...
- A quick burst of light snow passes across the U.P. tonight.
We could see a dusting near the state-line and along Lake
Michigan up to a fluffy inch in the Keweenaw and possibly the
north central.
- Lake-effect snow starts up again over the area Tuesday,
possibly continuing into Thursday.
- Blustery winds return Tuesday into Wednesday.
- Northwest high-end gales and heavy freezing spray expected
Tuesday night and Wednesday across central and eastern Lake
Superior.
- Another shot for snow comes Thursday night/Friday.
&&
.SHORT TERM /THROUGH TONIGHT/...
Issued at 241 PM EDT Mon Mar 18 2024
Radar and satellite imagery show the lake-effect snowfall ending
across Upper Michigan this afternoon, with ridging building in from
the west already bringing partly cloudy skies to Ironwood as of 2 PM
EDT. As this occurs, we could see some additional clearing over the
western U.P. this afternoon, which may raise temperatures a little
bit more than what I forecasted this morning. Nevertheless, with
another shortwave quickly digging down from northern Manitoba this
afternoon to Lake Superior Tuesday morning, expect to see some light
snow showers quickly move across the U.P. tonight. There could be
some moderate snow showers at times, particularly over the west and
north central (see the 12z HREF mean hourly snowfall rates for
reference). Therefore, we could see another dusting from the
Wisconsin border to the Lake Michigan shoreline to a fluffy inch
over the Keweenaw and maybe north central before 8 AM EDT Tuesday.
With temperatures getting into the low to mid 20s tonight and with
winds being lighter than what we`ve seen the previous couple of
days, we could see roads become slick in spots again for the morning
commute Tuesday. Therefore, be a little extra cautious Tuesday
morning, and watch out for some slick spots. As the cold air
advection behind the shortwave begins to work its way into the west
late tonight/early Tuesday morning, we could see some lake-effect
snow start up again over the northwest snow belts (see the 12z
NAMNest) (20% chance).
&&
.LONG TERM /TUESDAY THROUGH MONDAY/...
Issued at 329 PM EDT Mon Mar 18 2024
Not much has changed in the past 24 hours with respect how guidance
is projecting the eventual evolution of the pattern across North
America. Through the midweek period, the main setup will involve a
broad ridge/trough pattern from west to east across the continent,
positioning the forecast area in northwest flow. This will prove
favorable for another clipper system diving out of Canada, opening
the door for snow chances, more winter like temperatures, and gusty
winds. Toward the end of the week and weekend, the broad trough over
the eastern third of North American will lift and longitudinally
stretch across Canada. At the same time, eastward progressing deep
trough will push into the west coast. There appears to be a slowing
trend in the west coast troughing, which appears to be a factor into
a potential storm early next week. Overall though, confidence in the
latter half of this forecast period is low, but is increasing in
regards to a a quick hitting system Thursday night/Friday.
Light snow continues Tuesday courtesy of a passing clipper system,
gradually changing over to lake effect snow as the associated cold
front moves through during the afternoon. The bulk of the cold air
isn`t expected to surge in until Tuesday evening as a secondary
shortwave presses in. This will enable 850mb temps to plummet to
near -20C by Wednesday morning. As the surface low pulls away into
southern Ontario/eastern Quebec, stout high pressure will press
southeast out of the Canadian Prairies setting up persistent NW flow
over the Great Lakes. Together, all of this will kick off another
lake effect snow episode and blustery winds Tuesday night and
Wednesday. Model soundings show lift co-located with the DGZ and
inversion heights upwards of 7k feet. But they also include an
inverted V signature below the cloud base, indicative of a dry near
surface layer that will need to be overcome for significant snow
accumulations. Models vary on the impact this could have on the
snow. Ensembles show a 60-90% chance a widespread 1-2 inches of snow
across the NW wind snow belts by Wednesday afternoon, and while
higher embedded amounts would be expected where we can see some
terrain enhancement as well as throughout the eastern UP courtesy of
the longer fetch off of Superior, exact amounts remain uncertain.
This will bear monitoring, as we could be flirting with advisory
amounts out there. Expect snow showers to linger across the east
into early Thursday, but end Wednesday afternoon or evening in the
west. The resulting strong pressure gradient between the low and
high and cold air advection will provide an ideal environment for
blustery winds. Daytime heating during the day Wednesday will enable
more widespread blustery conditions. Right now, 30-40 mph northwest
winds are expected near the lakeshores, with 25-35 mph possible
elsewhere. The strong winds may also support some beach
erosion/lakeshore flooding concerns for Alger and Luce counties
during the day Wednesday.
As this system pulls away later Wednesday night, a closed low will
drop into Hudson Bay while a weak middle stream shortwave presses
due east across the north-central Plains and a southern stream into
the Deep South. On Friday, a slug of isentropic ascent tied to a
weak warm front associated with the middle shortwave will stretch
eastward into the Upper Midwest. This could touch off some light
snow across the area, though our best chances will be across the
southern UP.
This weekend, guidance suggests a deep and potent shortwave will
begin organizing and lift out of the Rockies. As expected this far
out, there`s considerable spread among the ensemble systems on its
track and where the warm/cold air will be; but given the spread in
possibilities, its recommended that anyone with travel plans Sunday
into early next week keep tabs on the forecast.
&&
.AVIATION /06Z TAFS THROUGH 06Z WEDNESDAY/...
Issued at 125 AM EDT Tue Mar 19 2024
Light snow associated with a disturbance has already spread across
most of the w and c portions of Upper MI. In its wake, expect VFR to
prevail overnight at IWD/CMX/SAW. During today, MVFR cigs should
develop at all terminals soon after sunrise. While those cigs are
expected to lift to just above 3000ft in the aftn, MVFR cigs may
hold on thru the day. Sct -shsn will begin to develop across the
area during the day under cyclonic flow. Vis may drop to briefly to
MVFR at times. As incoming air mass becomes increasingly colder
tonight, lake effect shsn will become more widespread with greater
fluctuations in vis btwn IFR and VFR possible. NW winds will be
gusty to 25-35kt today into tonight at all terminals, strongest at
CMX.
&&
.MARINE...
Issued at 329 PM EDT Mon Mar 18 2024
Winds gradually backing more to the W and eventually SW fall back
largely to around 20 knots across the lake this evening, but will
increase to around 20 to 30 knots across the western half of Lake
Superior into the early hours of Tuesday. Another system moving
through the region Tuesday through Wednesday then will bring another
punch of colder air and tighter pressure gradient, with the threat
for gales across the east half increasing Tuesday night into
Wednesday. Internal probabilistic guidance shows around a 30-50%
chance for gales beginning by Tuesday evening, then a 50-80% chance
for high end gales beginning Tuesday night. There is a low chance
(<25%) for storm force winds as well. Given this level of
confidence, a Gale Warning is in effect for much of Lake Superior
Tuesday evening through Wednesday evening. Additionally, the
combination of cold air and strong winds, an environment favorable
for heavy freezing spray development is likely (>75%). Winds
decrease Wednesday night, coming in at or below 20 knots the rest of
the week before increasing to around 20 to 25 knots Saturday.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
Upper Michigan...
None.
Lake Superior...
Small Craft Advisory until 8 PM EDT /7 PM CDT/ this evening
for LSZ240>242.
Gale Warning from 8 PM EDT /7 PM CDT/ this evening to 11 AM
EDT /10 AM CDT/ Wednesday for LSZ240>242-263.
Small Craft Advisory until 2 PM EDT this afternoon for LSZ243-
244.
Gale Warning from 2 PM this afternoon to 11 PM EDT Wednesday
for LSZ243>251-264>267.
Small Craft Advisory from 11 AM this morning to 2 PM EDT this
afternoon for LSZ245>251.
Small Craft Advisory until 2 AM EDT early this morning for
LSZ250-251.
Lake Michigan...
Small Craft Advisory from 11 PM this evening to 8 PM EDT
Wednesday for LMZ221-248-250.
&&
$$
SHORT TERM...TAP
LONG TERM...LC
AVIATION...Rolfson
MARINE...LC