Area Forecast Discussion Issued by NWS Marquette, MI
000
FXUS63 KMQT 131801
AFDMQT
Area Forecast Discussion
National Weather Service Marquette MI
201 PM EDT Wed Mar 13 2024
.KEY MESSAGES...
- Despite a gradual cooling trend, temps will remain above normal
through the end of the week.
- Little, if any, precipitation expected until this weekend.
- A significant pattern change will result in below normal
temperatures early next week, but then it appears temperatures
will moderate and rebound above normal again by the middle of next
week.
&&
.SHORT TERM /THROUGH TONIGHT/...
Issued at 306 AM EDT Wed Mar 13 2024
GOES-16 WV imagery shows a dry airmass behind a surface trough over
Georgian Bay at 06Z. METARS around the UP are reporting clear skies
and temperatures in the 30s, though a few RAWS sites are already in
the 20s. This will lead to a repeat of last night where each ESTF
update will likely push the morning low further and further down.
Despite primarily northerly and northwesterly flow, unseasonable
highs are still expected today, with bias-corrected guidance still
forecasting temperatures in the mid-60s from IMT to MNM with upper
40s to upper 50s elsewhere. The HREF is a bit of a mixed bag of
cloud solutions today, with a mix of mid to high level clouds being
forecast to varying degrees depending on the ensemble member. This
forecast package will split the middle at partly to mostly cloudy
skies today. Tds have been nudged downwards, though not to the
extent of yesterday. Still, the interior west could see RHs falling
into the 20s again, though confidence is lower as a cloudier day
could reduce radiational heating and make mixing less efficient.
Fire weather concerns should be limited based on wind gusts below 10
mph. Tonight, expect lows around freezing with more definitely cloud
cover ahead of a weak surface low passing well south of the UP. This
forecast package removed PoPs prior to 12Z as the HREF shows below
15% probability of any hourly QPF values exceeding 0.01 inches,
though various members of the HREF do show precipitation approaching
MNM around 12Z.
&&
.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...GS
LONG TERM...Voss
AVIATION...Jablonski
MARINE...Voss