040
FXUS63 KMQT 130915
AFDMQT

Area Forecast Discussion
National Weather Service Marquette MI
515 AM EDT Thu Jun 13 2024

.KEY MESSAGES...

- Gusty northwest winds are expected today along with additional
  chances for isolated showers and thunderstorms. There is a
  marginal risk (category 1/5) of severe weather for most of the
  UP, with the main threats being large hail in excess of an
  inch and damaging winds in excess of 60 mph.

- Dry Friday and early Saturday before the return of showers and
  thunderstorms later in the weekend.

- Warmer than normal temperatures frequent the forecast, with
  some areas approaching 90 for highs by next week.

&&

.SHORT TERM /THROUGH THIS AFTERNOON/...
Issued at 514 AM EDT Thu Jun 13 2024

RAP analysis shows a mid level trough over southern Manitoba with a
weak low pressure trough at 1004 mb extending over Lake Superior and
into the UP. A cold front drapes from western lake superior
northeast into northern Ontario. Showers and lingering thunderstorms
have almost made their way out of the UP, but dry weather is
expected within the next hour as PVA diminishes and this sfc low
pressure trough slowly moves east this morning.

This dry period is only expected to be brief as mid level trough
rotates east through northern Ontario, sending a stream of vorticity
south across the UP today. As the sfc low pressure trough progresses
east toward Quebec, it deepens and brings the cold front eastward
across the UP through early this afternoon. CAMs do not have the
greatest agreement on the timing of shower and storm activity today,
but there does seem to be a consensus on two periods. The first one
being a round progressing east across the UP with the cold front.
The second period would be more PVA forced in the later part of the
afternoon. The marginal risk for much of the UP seems appropriate
for today as neither of these rounds is a home run. Bulk shear of
~50 kts will be sufficient for storms throughout the day, but the
best instability (6/13 0z HREF mean SBCAPE to around 1000 J/kg) is
expected in the earlier part of the afternoon ahead of mid level
lapse rates increasing to near 7C/km. That said, some isolated
stronger to severe storms are possible. If any severe storms are
able to develop (5% chance), the main threats will be hail and winds.

CAA and drier air behind the cold front will allow for some good
mixing resulting in some gusty northwest winds. While the 6/13 0z
HREF indicates only a 40-60% chance of wind gusts exceeding 30 mph,
model soundings do indicate the potential for isolated gusts as high
as 40 to even 50 mph. These gusts are not expected to be
consistently high enough for an advisory, but it will still be a
gusty day. Highs for the most part are expected in the 70s with the
south central UP being warmer in the low to mid 80s. The other
exception to highs in the 70s would be those near Lake Superior
which may only see highs in the 60s.

&&

.LONG TERM /THURSDAY THROUGH WEDNESDAY/...
Issued at 335 PM EDT Wed Jun 12 2024

The active weather pattern across the CONUS continues through the
long-term forecast. The main features of note at 500mb are a trough
passing over Lake Superior Thursday and a deep cutoff low off the
coast of the Baja California, which will be the cause of active
weather over the weekend. Despite high pressure keeping a day of ,
the overall weather pattern through the long term is wetter than
normal and warmer than normal, with some of the hottest temperatures
of the year thus far forecast for Monday.

Thursday, the aforementioned trough will pass over the area. 850mb
cold advection and dry air behind the trough will allow for 20-30kt
winds to mix down to the surface. EFI shift of tails has backed off
somewhat but the Euro ensemble still calls for the potential of
gusts up to 35 mph. These gusts will almost certainly (90+%) not be
consistently high enough for an advisory but it will still be a
gusty day. CAMs call for some diurnal showers supported by post-
tropa clearing allowing for some radiational heating, but only
isolated thunderstorms are expected. Highs look to be in the 70s for
the most part except for the southern reaches of the UP reaching
into the 80s and some of the near-Lake Superior communities only
seeing highs in the 60s.

Once showers move out of the UP entirely Thursday evening, dry
weather will be over the UP through at least Saturday morning as
ridging aloft builds in and supports a near-1020mb high pressure
over the Upper Great Lakes. Friday will be a slightly cooler day
with highs only in the 60s to low 70s, but highs recover to the mid
70s for Saturday. RHs look to fall into the 40s and 30s, but with
very light winds, weather should be benign to end the work week and
begin the weekend.

Meanwhile, the deep cutoff low over the Pacific will deamplify and
shift northeast through the Rockies. The GEFS shows a low pressure
will develop in the Canadian Prairie, with the GEFS suggesting a
central pressure potentially below 990mb and perhaps into the 970s
mb over Manitoba by Sunday afternoon. With high pressure shifting to
the east, predominantly southerly low level flow will allow Gulf
moisture to surge north, as shown in the NAEFS vapor transport being
at the 90th percentile of climatology along with PWATs of near 1.5
inches. As the weakening trough approaches the Upper Great Lakes and
the cold front of the Canadian Low approaches, multiple lifting
mechanisms for showers and thunderstorms will be present, with PoPs
spreading west to east beginning Saturday PM. As the pattern is
complex, details on the strength and timing of storms is tough to
narrow down, so look for future forecast packages to gain clarity
there, but with the available moisture to work with, ensembles do
show about a 15% chance of daily precip totals to exceed an inch by
Sunday. This is a little lower than the last 24 hours of guidance,
but still enough to maintain some concern about weekend outdoor
plans that would be ruined by a downpour.

The gradual warmup continues into next week, with high 80s in the
forecast for Monday, with widespread low to mid 90s in the 75th
percentile of the NBM. PoPs remain in the rest of the long term
forecast as ensembles show a continued chaotic pattern through mid-
June. The general pattern looks to support ridging over the eastern
CONUS with a persistent surface high off the East Coast, which
should help create southerly to southwesterly flow to advect further
Gulf moisture north. As a result, the CPC outlooks the 8-14 day
period as being more likely to be warmer than normal and wetter than
normal.

&&

.AVIATION /06Z TAFS THROUGH 06Z FRIDAY/...
Issued at 115 AM EDT Thu Jun 13 2024

Lingering showers and thunderstorms near KSAW will continue pressing
east after issuance, but expect improving conditions soon
afterwards. In the wake of tonight`s storms, low level moisture will
support MVFR ceilings at KCMX and potentially some fog. After the
sun rises, expect improving ceilings to VFR at all sites and daytime
mixing to support gusty conditions. Current forecast is for 25-30kt
westerlies, but some guidance suggests mixing could support upwards
of 40kts in some areas by afternoon Thursday.

&&

.MARINE...
Issued at 324 AM EDT Thu Jun 13 2024

Southwesterly winds will become west-northwesterly and increase
behind a cold front later this morning with gusts of 20 to 25 knots.
By Friday, winds will return to less than 20 knots with the return
of high pressure where they will stay until early Sunday morning. At
that point, the next cold front will bring southerly winds of 20 to
25 knots along with 4 to 5 foot waves along the US/Canada border on
Lake Superior.  In addition, thunderstorm chances will return to the
forecast, but it is too early to determine severity.

&&

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

&&

$$

SHORT TERM...Jablonski
LONG TERM...GS
AVIATION...JTP
MARINE...TDUD