388
FXUS63 KMQT 280729
AFDMQT

Area Forecast Discussion
National Weather Service Marquette MI
329 AM EDT Sun Apr 28 2024

.KEY MESSAGES...

- Much cooler today with showers lifting from south to north
  during the afternoon.
- Active pattern continues as 3-4 low pressure systems track
  across the region over the next week. Above normal
  temps/precip are expected including thunderstorm chances.

&&

.SHORT TERM /THROUGH THIS AFTERNOON/...
Issued at 328 AM EDT Sun Apr 28 2024

Water vapor imagery and RAP analysis show that the shortwave that
affected Upper MI yesterday is now e and ne of Lake Superior. The
next shortwave has lifted out of the southern Rockies and out over
the western Plains. This wave is supporting a long band of
convection from TX to eastern KS, then to northern IL/IN. Frontal
boundary associated with the former wave is supporting additional
convection across central Lwr MI with even a few -shra back to near
Menominee. Across Upper MI, sfc winds are in the process of veering
n to ne in response to sfc high pres building into northern Ontario
and low pres over s central KS. In this veering upslope flow, some
-dz has developed into portions of western and n central Upper MI.
This -dz may linger for another couple of hrs. Under cloudy skies,
temps at 07z mostly range thru the 40s F, but it`s still in the low
50s at Menominee, and upper 30s are becoming more common across the
w to n central.

Today will be a much cooler day than yesterday under ne winds btwn
high pres building over northern Ontario and low pres lifting to IA.
Many locations will have high temps 15-25F lwr than yesterday. Under
generally cloudy skies, expect high temps today around 40 to the mid
40s w to n central ranging up to the low/mid 50s e. As low pres
lifts to IA today, strengthening waa/isentropic ascent will spread
into the Upper Great Lakes along with a nice push of 850-700mb
moisture transport. In addition, sharpening 850mb warm front will
approach. End result will be an organizing area of shra that will
lift n out of WI into Upper MI this aftn. Consensus of recent
guidance suggests -shra should reach Menominee County early aftn and
then slowly/steadily lift n during the aftn, though there is
uncertainly in how far n pcpn will get before 00z. While no pcpn
will reach the Keweenaw thru 00z, there is uncertainty across the
rest of northern Upper MI. It`s possible areas from Ontonagon to
L`anse, Marquette and Munising/Grand Marais will remain dry thru 00z
as well, but there is sufficient support for at least a 20-50pct chc
mention in those areas 22-24z.

&&

.LONG TERM /SUNDAY THROUGH SATURDAY/...
Issued at 456 PM EDT Sat Apr 27 2024

The extended forecast period will be active with fairly good
agreement in the model guidance through Wednesday. Even though the
guidance begins to diverge into the latter part of next week, the
consensus on a wet and active pattern holds true.

Sunday will start off dry with a high pressure over northern Ontario
and the negatively tilted trough over NE and KS. During the day, the
trough lifts northeast toward the Upper Midwest and the associated
sfc low tracks from KS to IA. Weak WAA and isentropic ascent ahead
of the low will try to increase showers from the south, however the
drier northeast flow looks to slow this down and limit showers to
the south central in the afternoon. Showers overspread the UP Sunday
night as the trough moves into MN and the sfc low lifts north-
northeast bringing better forcing and a ~45kt LLJ over the UP. There
could be some rumbles of thunder in the south central Sunday night.
Some breezy east winds are expected to mix down from the LLJ with
gusts up to 35 mph, especially in the eastern UP and Keweenaw Sunday
night through Monday morning. The trough then pivots northeast over
the UP on Monday reinvigorating the showers and possibly providing
enough forcing for some weaker thunderstorms. That being said,
strong storms are not expected as instability is limited with spotty
MUCAPE around 200j/kg, the inversion in model soundings is fairly
strong, and mid level lapse rates are mostly below 6C/km. PWATs
highlight a surge of ample moisture off the Gulf of Mexico, bringing
up to 1" to the UP Monday morning, which is noted above the NAEFS
90th percentile for Sunday night into Monday. This should bring a
good soaking to the UP with 0.5" to 1.5" of rain by Monday night and
help alleviate fire weather concerns for the next few days.

Showers lift north out of the UP Monday night as the trough and sfc
low lift over Lake Superior, temporarily bringing dry weather back
to the UP for Tuesday and diminishing winds. WAA during the day
accompanied by clearing skies will bring above normal highs in the
50s near Lake Superior and in the far east with 60s elsewhere. The
dry weather is quickly replaced Tuesday evening as a shortwave races
across the Plains, passing over the Upper Great Lakes Tuesday night
into Wednesday morning. The sfc low associated with this shortwave
looks to pass northeast through MN into northern Ontario bringing a
round of showers Tuesday night into Wednesday. Instability again is
fairly low, so only a few rumbles of thunder are expected at this
time.

Dry weather looks to follow for Wednesday with some breezy west
winds behind the low pressure system`s cold front. Current NBM
probabilities of wind gusts exceeding 40 mph is around 15-30%, so
expected gusts are around 25-35mph. Uncertainty begins to grow in
the forecast for the rest of the week, but chances for precip
increase toward the end of the week as we track out the next low
pressure system or two to move through the Great Lakes.

&&

.AVIATION /06Z TAFS THROUGH 06Z MONDAY/...
Issued at 126 AM EDT Sun Apr 28 2024

Medium to high confidence in IFR at IWD with persistent
upsloping early in the northerly winds behind departing low
pressure system. Confidence is low, however, in MVFR conditions
continuing at CMX and SAW through this morning, so will carry a
mention of IFR. Anticipate much fluctuation through the morning
hours though overall with increasing confidence in MVFR
becoming predominant by early afternoon. Northeasterly winds
will increase this afternoon at IWD/SAW followed by CMX this
evening, gusts in excess of 30 kts possible.

&&

.MARINE...
Issued at 456 PM EDT Sat Apr 27 2024

A few west gale force gusts to 35 kt are possible for a brief period
late this afternoon into the evening across eastern Lake Superior as
the low pressure moves northeast into northern Ontario. Winds back
northeasterly late tonight into Sunday as the next system approaches
from the southwest. Northeast gales up to 40 kt are expected across
the far western lake Sunday afternoon with northeast becoming
easterly gales to 40 kts spreading across the entire lake Sunday
night. While a few gusts may exceed 40 kts Sunday night into Monday,
highest probabilities are on the low end (25-45%). The strongest
winds are expected in the far east as well as the north central
portion of the lake between the Keweenaw and Isle Royale where there
could be some channeling. Gales quickly diminish Monday afternoon as
the low pressure tracks across western Lake Superior Monday night.
The Gale Watch has been upgraded to a Gale Warning, now starting at
18z Sunday in the far west (3z Monday elsewhere) and ending at 21z
Monday.

During the gale event, waves will be highest from Duluth Harbor to
the Bayfield Peninsula, with significant wave heights up to 14 ft
possible Monday morning. Wave heights Monday morning around Isle
Royale will also be higher, up to 13 ft. Waves across the lake fall
below 8 ft Monday evening. There also is a slight chance for
thunderstorms on Monday.

Winds fall below 20 kts Monday night, mainly remaining below until
Wednesday morning.

&&

.MQT WATCHES/WARNINGS/ADVISORIES...
Upper Michigan...
None.
Lake Superior...
  Gale Warning from 2 PM EDT /1 PM CDT/ this afternoon to 5 PM
     EDT /4 PM CDT/ Monday for LSZ162.

  Small Craft Advisory until 8 PM EDT /7 PM CDT/ Monday for
     LSZ240-241.

  Small Craft Advisory until 7 PM EDT Monday for LSZ242.

  Small Craft Advisory until 11 PM EDT this evening for
     LSZ243>245.

  Gale Warning from 11 PM this evening to 5 PM EDT Monday for
     LSZ243>246-263>266.

  Small Craft Advisory from 7 AM this morning to 8 PM EDT Monday
     for LSZ247-248.

  Small Craft Advisory until 5 PM EDT Monday for LSZ249>251.

Lake Michigan...
  Small Craft Advisory until 5 AM EDT early this morning for
     LMZ248-250.

&&

$$

SHORT TERM...Rolfson
LONG TERM...Jablonski
AVIATION...TDUD
MARINE...Jablonski