196
FXUS63 KMQT 171901
AFDMQT

Area Forecast Discussion
National Weather Service Marquette MI
301 PM EDT Wed Jul 17 2024

.KEY MESSAGES...

- Light scattered lake-effect rain showers end from west to east
this afternoon.

-Dry weather Thursday and Friday.

-Best chances for rain (up to 40%) in the interior west on Saturday.
Impacts should be minimal.

&&

.SHORT TERM /THROUGH TONIGHT/...
Issued at 244 PM EDT Wed Jul 17 2024

Scattered light lake-effect rain showers continue across Upper
Michigan this afternoon as cold air advection has brought 850mb
temps as low as 5C over Lake Superior, where water temperatures of
20+C are currently being seen. As high pressure continues to build
in from the west the rest of today through tonight, expect the lake-
effect cloud cover and rain showers to dissipate from west to east
this afternoon, eventually ending late this afternoon over the east.
Due to the lake-effect cloud cover across the area today and the
cold air that`s dropped down from Canada, temperatures have
struggled to get into the 60s across the north central and west,
making the area feel like it`s more of a September day today.
Meanwhile, the south central and east have comfortably reached the
60s, with the Menominee airport having just reached 70 recently.

Moving into the overnight period, expect clear skies. Given the
antecedent cooler air over us tonight and the clear skies, we could
see temperatures plummet into the low 40s over the interior west
late. In addition, we could see some patchy fog develop late tonight
too, but confidence is fairly low (20-30%) given that dry air is
moving into the area and CAM soundings don`t show temperatures
reaching the dewpoints during the overnight period. Nevertheless,
given the lake-effect rainfall today, some patches of fog could
develop.

&&

.LONG TERM /THURSDAY THROUGH TUESDAY/...
Issued at 259 PM EDT Wed Jul 17 2024

The pattern aloft is fairly stagnant over much of the CONUS as a
large ridge over the Four Corners region will not progress much
through the forecast period, paired with broad troughing over
the US Southeast. To the north in Canada, anomalous 500mb
ridging extending north from the Four Corners right will cause
height anomalies to 20+ dam by Sunday. Despite the ridge causing
prevailing northwesterly flow aloft which typically brings
cooler air to the UP, the upstream anomalous heat associated
with that ridge will counter the usually cooler pattern,
resulting in mainly seasonal temperatures over the UP through
this forecast period. A deep trough passing through the eastern
Hudson Bay and Quebec will perturb the flow pattern enough to
cause some weak shortwaves that in junction with diurnal
heating, will cause some periodic low (15-35%) chances of
showers and isolated thunder in the interior west particularly
later in the forecast period.

Thursday and Friday will be dry as a 1022 mb high pressure slides
south of the region. Highs will continue a warming trend, with highs
in the 70s Thursday and low 80s Friday.

The next credible chances of precipitation reenter the forecast
Saturday as a weakening surface trough passes through the area in
response to a trough aloft passing through Quebec and the eastern
Hudson Bay area. Given how weak the synoptic forcing is, the showers
that do form will need a boost from diurnal heating, thus the
highest PoPs are in the interior west. With 00Z LREF mean SBCAPE
values around 400 J/kg, some thunder is possible especially along
the MI/WI state line but nothing severe is expected. Ensemble
solutions that keep the track of the surface trough a bit slower are
present enough to keep some slight (15-20%) diurnal PoPs right along
the state line for Sunday afternoon, but otherwise it should be a
pleasant Sunday with highs around 80. Ensembles diverge into next
week, but ensemble mean 500mb plots do show the ridge over the
Canadian Plains retreating somewhat and northwesterly flow
dominating over the UP, which should support weak clipper shortwaves
bringing periodic, low-impact rain chances for next week.

&&

.AVIATION /18Z TAFS THROUGH 18Z THURSDAY/...
Issued at 253 PM EDT Wed Jul 17 2024

TAFs look to improve to VFR over the next few hours as the lake-
effect cloud deck gives way to high pressure ridging to our west.
The northwest to northerly gusty winds this afternoon will slowly
die down as the high pressure builds in. Expect fairly light winds
and calm/SKC conditions across the TAF sites tonight through
Thursday morning. That being said, there is a small (20% or less)
chance of some patchy fog moving over the TAF sites tonight due to
the temperatures plummeting to the dewpoint.

&&

.MARINE...
Issued at 259 PM EDT Wed Jul 17 2024

Northwest winds of 20-25 knots will diminish tonight across eastern
Lake Superior as a trough axis departs from the lake. After that,
the remainder of the forecast will have sub-20 kt wind gusts with
the exception of Friday afternoon, where the region of Lake Superior
between the Keweenaw Peninsula and Isle Royale will see
southwesterly wind gusts of 20-25 knots due to a disturbance in
Canada tightening the pressure gradient. Once wave heights fall
below 4 feet tonight, expect waves to remain below 4 feet through
the forecast period.

&&

.MQT WATCHES/WARNINGS/ADVISORIES...
Upper Michigan...
  Beach Hazards Statement until 11 PM EDT this evening for
     MIZ005-006.

Lake Superior...
None.
Lake Michigan...
None.

&&

$$

SHORT TERM...TAP
LONG TERM...GS
AVIATION...TAP
MARINE...GS