223
FXUS63 KMQT 020719
AFDMQT

Area Forecast Discussion
National Weather Service Marquette MI
319 AM EDT Sun Jun 2 2024

.KEY MESSAGES...

- Patchy fog expands until sunrise and will become locally
  dense. Fog will burn off within a couple of hours after
  sunrise. Marine fog on portions of Lake Superior may be an
  issue through the day.
- Isolated afternoon showers possible interior eastern Upper MI
  due to converging lake breezes.
- Frequent opportunities for showers and thunderstorms over the
  next 7 days, with a break expected today and possibly
  Tuesday.
- Above normal temperatures through the first half of the week,
  then turning cooler for the last half and next weekend.

&&

.SHORT TERM /THROUGH TONIGHT/...
Issued at 318 AM EDT Sun Jun 2 2024

Water vapor imagery and RAP analysis show a deep mid-level low
centered over northern Manitoba. To the s of this feature, flow is
zonally oriented along the U.S./Canada border from the Pacific NW to
Lake Superior. Upstream, the next shortwaves of interest are over
the northern Rockies. Shortwave that was over far northern ND 24hrs
ago has lifted ne and is nearing James Bay. This wave has helped to
drive a drier air mass aloft into Upper MI. At the sfc, a weak high
pres ridge is over the Upper Mississippi Valley. Weak pres gradient
over the fcst area is leading to light/calm wind at many locations
early this morning. Where skies are clearing and where rainfall
occurred yesterday and last evening, the light wind is allowing
radiation fog to develop. So far, coverage is limited. Current
temps range thru the 50s F.

Expect fog to expand thru sunrise as areas of lingering cloudiness
clear out. The fog will likely become locally dense. As we are just
under 3 weeks from the summer solstice, fog should quickly burn off
within a couple of hrs of sunrise as insolation rapidly increases,
leaving behind sunny skies. Aforementioned sfc high pres ridge will
shift to the western Great Lakes today, allowing lake breeze
circulations to rule the day. Over the eastern fcst area, the
converging lake breezes from Lake MI and Lake Superior raise the
prospect for a few -shra to develop. Models suggest at least a few
hundred j/kg of MLCAPE developing, but as is often the case, the NAM
is greatest. The NAMnest has upwards of 1000j/kg of MLCAPE and will
be discounted. Based on fcst soundings, it appears there will be cap
to sfc based convection somewhere in the 10-15kft range, so cloud
depth should be sufficient for isold -shra development, but not
thunder unless the outlier higher MLCAPE solution occurs. Fcst for
the aftn will reflect schc pops, around 20pct, centered across
southern Luce County where signal from models is most consistent,
but isold -shra could occur as far w as northern Delta/adjacent
Alger counties. To the w, building mixed layer will tap drier air,
driving dwpts down to the upper 30s/lwr 40s F interior w half. With
aftn temps in the 75-80F range, RH will tumble toward 25pct. Winds
will be very light in that area today, not much more than around
5mph, limiting fire wx concerns.

&&

.LONG TERM /SUNDAY THROUGH SATURDAY/...
Issued at 431 PM EDT Sat Jun 1 2024

Expect dry conditions to return to the U.P. early Sunday morning as
the cold front currently tracking across the western UP exits into
Ontario. Weak sfc ridging returns to the area for Sunday with light
winds and abundant sunshine allowing temps to warm to around 80F
amidst deep mixing to around 6-7 kft across the interior west. Even
though there isn`t an extremely dry layer to mix into, min RH values
dipping below 30% seem likely but light winds and recent rainfall
preclude a greater fire risk. Warm temps and light winds also
instigate lake breezes that should converge across the eastern UP.
Lingering low level moisture may be sufficient for converging lake
breezes to initiate a few showers, with around 30% of HREF
members highlighting a small area around Newberry with lower
chances around 10% across the remainder of the eastern UP. The
NAMnest was one of the models that developed a shower around
Newberry and soundings indicate equilibrium levels around 10 kft
and initially deep inverted-v profiles that may evaporate most
of the precipitation. All that`s to say any rain that occurs
will be tough to measure.

Moving into Sunday night, expect mostly clear skies early before
decaying convection across the Northern Plains sends clouds our way
late. There`s also a chance for a few rain showers or perhaps a
thunderstorm across the far west, but latest model guidance
continues to be trend toward a slower onset of showers. In addition,
the model consensus shows little -if any- CAPE to work with,
probably due to cloud cover and southeast flow off the cold waters
of the lower Great Lakes. The better chance for showers and
thunderstorms is Monday afternoon/evening during peak heating if the
slower cold front is still across our area. Bulk shear values around
20-25 knots could result in a few stronger pulsey storms, but
thunderstorm chances are closely linked with frontal timing.

A drier air mass follows the cool front for Tuesday, but pwat values
stay above normal with due southerly flow extending all the way to
the western Gulf of Mexico. By Tuesday afternoon, a negatively tiled
shortwave or perhaps closed low develops across the Northern Plains
or Canadian Prairies with an associated ~990 mb surface low west of
Lake Winnipeg. As with the previous system, timing the frontal
boundary will be important for any associated thunderstorm chances
and there doesn`t appear to be a model trend at this time. However,
the most likely outcome appears to be strong to severe thunderstorms
develop to our west across the Northern Plains on Tuesday with the
decaying remnants moving into our area Tuesday night. EFI guidance
is hinting at potential for seasonably unusual CAPE and QPF Tuesday
into Wednesday across the west while NAEFS is highlighting pwats
>90th percentile implying heavy rain may be a prescient hazard.

Once the cold front passes through, the vertically-stacked low sits
over northern Ontario and brings cold air advection across our area.
As this occurs, expect additional weak shortwaves rotating around
the parent low to move across the Upper Great Lakes, bringing
additional rain shower chances to finish out the work week. Think
CAA and loss of Gulf of Mexico moisture limit thunder chances, but a
few rumbles can`t be ruled out around peak heating. CAA also results
in temperatures trending below normal late next week with highs in
the 60s and lows in the 40s.

&&

.AVIATION /06Z TAFS THROUGH 06Z MONDAY/...
Issued at 136 AM EDT Sun Jun 2 2024

Main impact this TAF period will be flight restrictions due to fog
formation.  VFR conditions will initially prevail early in TAF
period, but expect an abrupt deterioriation sometime in the
07-09Z time frame as fog forms with light winds. Model guidance
is pinpointing CMX for LIFR (possible VLIFR). But, will also
carry tempos for MVFR/IFR at IWD and SAW as well through at
least 12Z. Look for a return to VFR in the 12-14Z time frame.

&&

.MARINE...
Issued at 431 PM EDT Sat Jun 1 2024

Light winds of 20 knots or less continue across Lake Superior
through the weekend. Winds become southeasterly Sunday night
and increase to 20-25 kts by Monday morning ahead of a cold
front slowly tracking east across the lake on Monday. A
southerly low level jet accompanies this period of stronger
winds and stable conditions across the lake indicate potential
for stronger winds at higher elevation platforms. Behind the
front, expect a return to light winds Tuesday before the next
chance for stronger winds arrives with another cold front
Tuesday night into Wednesday. Southeasterly gusts ahead of the
front and southwesterly behind the front are forecast to gust to
around 20 kts, but cold air advection may reduce stability and
allow for better mixing and stronger winds behind the front.

Thunderstorms are possible across the south central and eastern
portions of Lake Superior this afternoon and evening as a weak cold
front moves through. Thunderstorm chances return from Monday morning
through early Tuesday morning as the second cold front tracks across
the lake. Additional thunder chances return late on Tuesday and
continue through Wednesday as yet another cold front pushes through
from west to east across the lake. No severe weather is expected
from thunderstorms at this time.

&&

.MQT WATCHES/WARNINGS/ADVISORIES...
Upper Michigan...
None.
Lake Superior...
  Dense Fog Advisory until 8 AM EDT /7 AM CDT/ this morning for
     LSZ162-263-264.

Lake Michigan...
None.

&&

$$

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