467
FXUS63 KMQT 251723
AFDMQT

Area Forecast Discussion
National Weather Service Marquette MI
123 PM EDT Wed Jun 25 2025

.KEY MESSAGES...

- This evening through Friday, rain overspreads the UP. 24-hour
  rain amounts of 1+ inch are 60% likely with rainfall totals
  up to 2 inches possible (10-30% chance, highest near Iron
  Mountain). The WPC Outlook for Excessive Rainfall is a Slight
  Risk (category 2 of 4).

- After near-normal temperatures this week, a brief warmup into
  the 80s is expected this weekend, with showers and
  thunderstorms possible (around 50%).

&&

.SHORT TERM /THROUGH THURSDAY/...
Issued at 447 AM EDT Wed Jun 25 2025

GOES-East nighttime microphysics shows some high clouds streaming
over the UP with some low level clouds over the interior-W and N-
central. The lack of insulating cloud cover is thanks to the 1024mb
high pressure and zonal flow aloft noted on the RAP analysis over
the Upper Great Lakes and N Ontario. This has helped temps settle
into the mid 40s to mid 50s, but a few obs have dipped into the low
40s and Yellow Dog has lowered to 37! Further cooling is expected to
bring most into the 40s yet this morning as winds remain calm.

Dry weather then persists at least into the early afternoon as the
high pressure begins to weaken and a shortwave approaches from the
SW. Highs are expected near normal in the mid 60s to upper 70s. Lake
breezes are also expected this afternoon. Chances for -shra increase
in the late afternoon from the SW as isentropic ascent ahead of the
shortwave provides some preluding lift. QPF ahead of tonight should
remain below 0.1" as prior afternoon mixing dries the low levels and
better moisture remains well to the S.

The first round of shra progress over the UP this evening through
tonight as the shortwave moves overhead, a LLJ strengthens, and
better Gulf moisture arrives. The focus of the heavier QPF is over
the central and SE where the strongest isentropic ascent is located.
Model soundings show a deep and moist warm cloud layer up to 13kft
as well as PWATs approaching near 2" in the far S; widespread PWATs
will be between 1.4-1.7" during the peak of the round. The 6/28 0Z
HREF probabilities of at least 0.5" by sunrise on Thu are around 50-
75% over the central UP with 15-25% over the W and parts of the E.
Given that instability is lacking, tsra are not anticipated save for
possibly near Menominee (~15% chance). Fcst first round totals: a
few hundreths in the Keweenaw, widespread 0.25-0.5" with up to ~1.0"
in the S-Central. Lows tonight will be in the 50s. The first round
of shra dissipates over the E into Thu as the shortwave departs, but
this is replaced with round two as a stronger shortwave begins its
track over the W and eventually brings it`s sfc low with it. This
brings similar conditions favorable for widespread QPF, but
placement of heaviest QPF is still a bit uncertain yet into Fri. NBM
probabilities of at least 1.0" of QPF through 0Z Fri are between 35-
65% across the CWA, highest in the central UP. For 2.0" or more, the
NBM shows a area of ~10-30% over the central UP, highest near Iron
Mountain. Otherwise highs on Thu will be cooler in the upper 50s to
60s.

&&

.LONG TERM /THURSDAY NIGHT THROUGH TUESDAY/...
Issued at 447 AM EDT Wed Jun 25 2025

Flash flooding would be the main concern into Friday, though the WPC
outlook for Excessive Rainfall remains around 15 percent. With
forcing waning through the day Friday, precipitation intensity and
chances also wane from west to east, with weak high pressure leading
to a dry Friday night into Saturday morning.

Into the weekend, with both major synoptic longwave features over
the CONUS this past week having decayed, quasi-zonal flow will
persist over the CONUS through the weekend, with the weather being
highly susceptible to weaker impulse shortwaves. Given the spread of
paths of such shortwaves for forcing, uncertainty in potential for
organized convection this weekend is high (and thus, no severe
thunderstorm outlooks for the UP yet), but ingredients will likely
be present as a warmup to the 80s is expected. With the warmth comes
surface instability with LREF mean surface CAPE growing to around
1500 J/kg in the interior west by 00Z Sunday and around 2000 J/kg by
00Z Monday, both coincident with about 25 kt of bulk shear to
organize convection.

Given the weakly-forced pattern, it is no surprise that the global
deterministics and ensembles rapidly diverge in how the next pattern
establishes itself, however, the most likely pattern for next week
looks to be ridging over the Rockies to Plains with troughing over
eastern North America. This leads to persistent high pressure over
the UP interrupted by clipper shortwaves riding over the ridge
bringing periodic rain chances but otherwise better chances at
warmer than normal conditions, which the CPC outlooks align with.

&&

.AVIATION /18Z TAFS THROUGH 18Z THURSDAY/...
Issued at 123 PM EDT Wed Jun 25 2025

VFR conditions at all sites are expected today. A disturbance
bringing abundant low level moisture will bring long-duration -SHRA
and gradually descending ceilings throughout this TAF period, with
SAW most likely to see IFR at around 50 percent chances, then IWD at
around 30 percent, then CMX at around 20 percent. All 3 sites are 10-
20 percent likely to even see a brief period of LIFR ceilings. -TSRA
chances are negligible at CMX and IWD, with around 15 percent
chances in the 12Z-15Z timeframe at SAW, but confidence is too low
to include in the TAF at this time. Some lull in the -SHRA is
expected in the late morning to early afternoon hours of tomorrow
before resuming in full after 18Z. Expect winds out of the east and
southeast at 5-10 knots with some gusts to 15-20 kt.

&&

.MARINE...
Issued at 447 AM EDT Wed Jun 25 2025

High pressure ridging will keep winds light and variable into
tonight. On Thu, NE winds increase to ~20 kts across the W arm of
the lake, then winds backing to the NNW into early Fri may gust to
near 20kts mainly across the eastern half of the lake. Winds fall
back below 20 kts by Fri afternoon as they back W. Another round of
showers and storms will also be possible Thu into Fri. Winds stay
below 20kts through the weekend.

&&

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

&&

$$

SHORT TERM...Jablonski
LONG TERM...GS/Jablonski
AVIATION...GS
MARINE...Jablonski