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000
FXUS63 KMQT 262115
AFDMQT

Area Forecast Discussion
National Weather Service Marquette MI
515 PM EDT Fri Apr 26 2024

.KEY MESSAGES...

-Elevated fire weather conditions continue into this evening
 with minimum relative humidity around 20-30 percent over much
 of the area accompanied by gusty south to southeast winds to
 20-30 mph.
-Low pressure systems bring light to moderate rain tonight into
 Saturday.
-Marginal risk for a few strong thunderstorms capable of hail
 and gusty winds south-central and east Saturday afternoon and
 evening, but confidence is low.
-Active pattern continues, with multiple low pressure systems
 bring chances of precipitation virtually all of Saturday night
 through next Thursday night.
-The WPC has issued a Marginal Risk of Excessive Rainfall
 Sunday into Monday for around an inch of rainfall across the
 UP.

&&

.SHORT TERM /THROUGH SATURDAY/...
Issued at 432 PM EDT Fri Apr 26 2024

Visible satellite shows high clouds continuing to filter in ahead of
the next low pressure system currently centered over NE as noted on
RAP analysis and WV imagery. Lingering mid level ridging and the
departing high pressure to our east set up another day of above
normal temps in the 50s to low 60s. While some spots in the west
could warm an additional degree or two into the mid 60s with
downsloping flow, peak afternoon temps will occur within the next
hour. The mixing this afternoon has brought southwest gusts to 20-30
mph across the UP with RHs in around 20-25% over the west with 25-
40% over the east and in the Keweenaw. This will continue elevated
fire weather conditions into the early evening.

The 4/26 12z HREF has the sfc low around 992 mb over northeast NE at
0z Saturday, continuing northeast tonight toward northwest WI by 12z
Saturday as it weakens to around 1000mb. Isentropic ascent will
eventually support showers lifting northeast across the UP this
evening once the dry air is eroded. Better PVA arriving after 6z
Saturday with the mid level shortwave reinvigorates showers and
possibly weak elevated convection tonight. MUCAPE peaks around 250-
500 j/kg and bulk shear is around 30 kts as a LLJ lifts into the
area, so no severe weather is expected. Lows are expected in the 40s.

The sfc low continues to weaken on Saturday as it moves northeast
across Lake Superior to northeastern Ontario. Moisture surges north
from the Gulf of Mexico into the Upper Great lakes moisture, mid
level lapse rates approach 7 C/km, MLCAPE is around 300-600 j/kg
(the NAM is higher around 600-1200 j/kg), and bulk shear of 50-60
kts. This set up is more than adequate for organized updrafts and
stronger storms. That being said, there are a few problems regarding
storm development. Destabilization may be negated by a mid-level
capping inversion, especially with lingering showers and cloud
cover. Also, the consensus of CAMs show the stronger convection
developing along the cold front once the frontal boundary is already
southeast of the UP. Overall confidence in severe thunderstorms in
our CWA is low, but the best chances are located along Lake
Michigan. Highs are expected above normal in the 60s to low 70s, but
could get higher over the south central given more clearing during
the day. Gusty southwest winds to 20-30 mph are also expected in the
afternoon and evening.

&&

.LONG TERM /SUNDAY THROUGH FRIDAY/...
Issued at 407 PM EDT Fri Apr 26 2024

The active weather pattern of late shows no signs of stopping
through the next week. By Saturday night, a handful of 500mb troughs
of various lengths are expected over the CONUS, which of most note
to interests in Upper Michigan are a departing trough over Lake
Superior and the next upstream trough, an anomalously deep (-13 dam
per 12Z GEFS) trough over the Four Corners region. Lagging showers
from the departing system will keep low PoPs in the forecast
Saturday night before the western trough negatively tilts and races
northeast to the Upper Great Lakes basin for the end of the weekend
and the beginning of next week. Attention then turns westward again
as an anomalous trough races along the USA/Canada border through the
early week and has ramifications on the precipitation pattern for
the middle of next week and beyond.

Saturday night, the trough affecting the weather earlier in the day
will be lifting into northern Ontario, leading to height rises over
the Upper Peninsula. This will act against any ongoing lingering
showers, but enough remaining shortwave energy and orographic uplift
from the northerly flow will keep some slight chance PoPs (15-30%)
in the forecast. GEFS mean precip in that time period is only a
couple of hundredths, so any showers that linger will be light in
nature.

Sunday morning, ahead of a 500mb trough exiting the Rockies, a near-
1000mb low pressure will be over the Central Plains. Isentropic
upglide ahead of the lifting warm front will bring gradually
increasing PoPs throughout the day. The warm front of the low should
arrive around Sunday evening with the cold front passing Monday
evening as the low transits through the Upper Great Lakes at around
1005 mb. Following strong 850mb CAA in the morning, Sunday will be
the coldest day of the week, with gridded MOS guidance showing highs
only in the 40s and lower 50s. ECMWF EFI SoT between 0 and 1 by
Monday indicates the potential for an unusually high
precipitation total potential. The NAEFS climatology percentiles
for vapor transport, PWAT, and humidity are all in the
90-99.5th percentile range through late Monday, leaving the
ingredients for some higher QPF forecasts. Ensemble forecasts do
have a somewhat high spread, but the range of plausible
forecasts (80% probability) is between a half inch of rain and 2
inches of rain by Monday night, leading to the WPC issuing a
Marginal Risk of Excessive Rainfall. A few rumbles of thunder
are also possible, with the GEFS and Canadian ensemble showing
generally up to 700 J/kg of SBCAPE especially on Monday.

Ensemble spread increases significantly following the passage of the
system by Tuesday, but the general idea is that a trough passing
along the USA/Canada border will support a low pressure tracking
just north of Lake Superior which should support rain showers
roughly in the late Tuesday/early Wednesday timeframe. Another
system could pass in the Thursday timeframe, but NBM PoPs of only 15-
30% highlight the uncertainty in the timing and location of such a
system. Confidence is increasing that ridging will build over the
region for next weekend, giving at least some period of time for the
UP to dry out. Soils could be particularly soggy by then, as the
GEFS accumulated QPF by the end of next week ranges from 1 to 4
inches.

&&

.AVIATION /18Z TAFS THROUGH 18Z SATURDAY/...
Issued at 207 PM EDT Fri Apr 26 2024

VFR conditions will continue through early this evening at all
TAF sites accompanied by some gusty southeast winds to 20-30 kts.
An approaching low pressure system then spreads scattered showers
into the UP tonight. These showers will be accompanied by lower
cigs, with all sites lowering to MVFR around or shortly after
midnight EST. IWD and CMX look to fall to low MVFR possibly IFR late
tonight/Saturday morning. There is higher confidence of SAW falling
to IFR late, potentially LIFR Saturday morning. All sites then look
to improve into Saturday afternoon as the low pressure begins to
depart northeastward. A low-level jet moving over the area will also
result in LLWS developing at all terminals tonight, continuing into
Saturday morning; wind shear at SAW may continue at SAW into the
early afternoon.

&&

.MARINE...
Issued at 530 AM EDT Fri Apr 26 2024

Southeast winds gusting up to 25 mph are occurring early this
morning with the strongest winds across the east half of the lake.
Southeast winds increase up to 30 knots across the eastern lake
Friday afternoon. A few gale force gusts up to 35 knots are possible
near the tip of the Keweenaw and the international border through
Saturday morning. A low pressure tracks across Lake Superior on
Saturday resulting in a period of light and variable winds. Cold air
advection increases Saturday night resulting in northerly winds
gusting up to 30 kts across north-central portions of the lake.
Another low pressure approaches Lake Superior on Sunday causing
winds to back northeasterly and increase to gales across the far
western lake. Winds back easterly Sunday night as gales spread
across all but far eastern Lake Superior. A local office tool
indicates 60-90% chances for 40-45 kt gales across the far
western lake Sunday afternoon and evening with lower 25-50%
chances across the north-central lake. Gales are forecast to
subside on Monday as the low`s center lifts across Lake
Superior. Winds become west- southwesterly Monday night while
decreasing to 20 to 25 knots. Light winds less than 20 knots
prevail Tuesday then another system moving through Tuesday night
and Wednesday increases west winds to around 25 kts.

Thunderstorms are possible over portions of Lake Superior tonight
through Saturday evening then again Sunday evening through Monday
evening.

&&

.MQT WATCHES/WARNINGS/ADVISORIES...
Upper Michigan...
None.
Lake Superior...
  Gale Watch from Sunday morning through Monday morning for
     LSZ162.

  Gale Watch from Sunday evening through Monday afternoon for
     LSZ242>246-264>266.

  Small Craft Advisory until 6 PM EDT Saturday for LSZ244-245-
     249-250.

  Small Craft Advisory until 2 PM EDT Saturday for LSZ246.

  Small Craft Advisory until 8 AM EDT Saturday for LSZ248.

  Small Craft Advisory until 8 PM EDT Saturday for LSZ251.

  Gale Watch from Sunday afternoon through Monday afternoon for
     LSZ263.

Lake Michigan...
  Small Craft Advisory from 5 AM to 8 PM EDT Saturday for LMZ221.

  Small Craft Advisory from 7 AM Saturday to 5 AM EDT Sunday for
     LMZ248.

  Small Craft Advisory from 5 AM Saturday to 5 AM EDT Sunday for
     LMZ250.

&&

$$

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