Area Forecast Discussion
Issued by NWS Marquette, MI

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FXUS63 KMQT 132004
AFDMQT

Area Forecast Discussion
National Weather Service Marquette MI
404 PM EDT Wed Mar 13 2024

.KEY MESSAGES...

- Dry weather and above normal temps expected through Friday night
- A weekend storm system brings light rain/snow mix on Saturday
  then ushers in below-normal temperatures and potential for
  several days of accumulating lake effect snow Saturday night -
  Tuesday.

&&

.SHORT TERM /THROUGH TONIGHT/...
Issued at 402 PM EDT Wed Mar 13 2024

A broad mid level ridge overhead and a sfc ridge building in from
the northwest are providing another unseasonably warm and dry day
for the U.P. GOES WV imagery shows some mid and high level clouds
currently passing eastward over the U.P. as well as some cumulus
developing along the lake breeze off Lake Superior in Marquette
County and the Lake Michigan lake breeze in Menominee/southern Delta
County; the Lake Superior lake breeze is also noted on radar data.
Mixing today is not quite as strong as yesterday with model
soundings only indicating mixing up to 2-3kft, but this still
brought down some lower dew point temps and lowered RHs into 20%
range over the interior west half of the U.P. with a few spots
dipping into the upper teens. Luckily, winds are staying lighter
than yesterday with gusts mainly staying below 15 mph so fire
weather concerns remain low. While some interior areas may see temps
climb an additional degree or two yet this afternoon, especially
near the WI/MI state line, we begin to cool off the rest of today.

The dry weather pattern with above normal temps continues tonight.
With high pressure to the north and east and a low pressure
approaching the region, light north to northeast winds set up
tonight and cloud cover continues to increase ahead of the low.
Temps are expected to settle into the upper 20s to low 30s.

&&

.LONG TERM /THURSDAY THROUGH TUESDAY/...
Issued at 350 AM EDT Wed Mar 13 2024

Strong ridging building along the W Coast with 500mb positive height
anomalies reaching near 340m will, in turn, force a deepening trough
over eastern N America, late week into the weekend. The trough will
reach its deepest point during the first half of next week, probably
Mon/Tue. As a result, temps will gradually trend downward beginning
today but should still remain above normal through the weekend. Next
week, expect blo normal temps for the early part of the week as
models and ensembles show a stronger clipper shortwave descending
into the base of the trough bringing a reinforcing shot of colder
air with it. As for pcpn, little, if any, pcpn is expected until
this weekend as air mass will be too dry for pcpn despite the
passage of shortwaves over or north of the area. Late week, the
building ridge over western N America will begin to force trough
amplification into eastern N America, and that should support at
least some chc of pcpn by this weekend. Thereafter, next week, the
western ridge/eastern trough pattern is suggestive of the potential
of periodic shortwaves dropping into eastern trough, leading to the
potential of light snow at times as well as some lake effect/lake
enhanced snow. We`re also well into the time of year now where the
development of cold upper level troughing overhead can support
diurnal snow showers developing across the area due to daytime
heating. So some of that will be possible as well.

Beginning Thursday into Friday, shortwave energy ejecting from a
developing closed low in the southwest U.S. will be forced northeast
by the shortwave leading the onset of the eastern trough
amplification. The deterministic ECMWF and EPS members support
keeping the shortwave and associated pcpn well south of the area on
Thu. The deterministic GFS and NAM show maybe south central and east
portions of the cwa getting into light mixed pcpn and some of
the GEFS members show this as well. The deterministic Canadian
now has trended south with the pcpn and only a few of the GEPS
members have pcpn reaching into south central and eastern
sections of the cwa. The last few days of the UKMET remain dry,
keeping pcpn well south. While it will be something to monitor
over the next few runs, most model guidance suggests the U.P.
should either stay mostly dry or maybe just the far south
central and east could see a light snow/rain mix on Thursday. An
elongated sfc ridge axis moving squarely over the U.P. on
Friday will continue the dry conditions. Look for highs both Thu
and Fri generally in the 40s, except for some mid to upper 30s
readings along Lake Superior.

Shortwave leading the trough amplification will then cross the Upper
Great Lakes over the weekend, bringing a rain/snow mix late Fri
night into Saturday transitioning to mostly all snow on Sunday. N to
NW flow LES will likely develop in the wake of the shortwave during
Sun into Mon time frame as ensemble median 850mb temps from the
EPS/GEFS/GEPS fall to around -15C by Mon. Ensemble probabilities are
not really suggestive of anything more than light, sub-advisory LES
accumulation for early next week. Models suggest LES should taper
off or end quickly from west to east during the day on Tuesday as
ridging/subsidence builds in from the west and 850 mb temps moderate
above -10C. Looks like it will continue dry into Wednesday with
continued moderating temps as broad mid-level ridging prevails
across the region.

&&

.AVIATION /18Z TAFS THROUGH 18Z THURSDAY/...
Issued at 201 PM EDT Wed Mar 13 2024

Under broad ridging aloft and sfc ridging building in from the
northwest, VFR conditions will prevail through most of the 18Z TAF
period. High clouds will build in from the west this afternoon, but
cigs will mainly stay above 150-200kft until tomorrow morning. A low
pressure system passing well to the south of the U.P. will help
increase low level moisture and provide some forcing for lower
clouds during the day Thursday, however confidence on exact timing
of MVFR cigs on Thursday is low at this time. The challenge this
afternoon will be the lake breeze impact at SAW. Mostly light and
variable winds are expected at all TAF sites through this evening
with northeast winds setting up tonight into Thursday.

&&

.MARINE...
Issued at 350 AM EDT Wed Mar 13 2024

A ridge of high pressure will prevail across Lake Superior keeping
winds 20 kt or less into Friday with the exception of maybe some 20-
25 kt northeast gusts in the far western arm of the lake on
Thursday. Looking ahead, southwesterly winds will increase Friday
night into Saturday ahead of a low pressure system with gusts of 20-
30 kt possible. Behind this system, strong northerly winds are
possible with cold advection resulting in unstable conditions over
the waters late Saturday night into early next week. Some model
ensembles suggest a 50-60 pct chance of low-end north-northwest
gales to 35 knots late Saturday night into Sunday over central
portions of the lake.

&&

.MQT WATCHES/WARNINGS/ADVISORIES...
Upper Michigan...
None.
Lake Superior...
None.
Lake Michigan...
None.

&&

$$

SHORT TERM...Jablonski
LONG TERM...Voss
AVIATION...Jablonski
MARINE...Voss


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