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000
FXUS63 KMQT 262009
AFDMQT

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

.KEY MESSAGES...

-Elevated fire weather conditions continue this afternoon with
 minimum relative humidity around 20-30 percent over much of the
 area accompanied by gusty south to southeast winds to
 20-30mph.
-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 THIS AFTERNOON/...
Issued at 257 AM EDT Fri Apr 26 2024

Water vapor imagery and RAP analysis show mid-level troffing over
western N America with a vigorous shortwave over CO that is
supporting shra/tsra across the Plains, particularly over Nebraska.
Downstream, mid-level ridging is over the Mississippi Valley,
extending into northern Ontario. The associated sfc high pres is
well to the e over Quebec and the ne U.S. Closer to home, it`s
another quiet night across the fcst area under clear skies. With the
sfc high pres well to the e and low pres over western KS, s to se
winds are stirring, particularly across western and northern Upper
MI. As a result, current temps are higher than yesterday at this
time despite the clear skies and similarly dry column. Current temps
mostly range thru the 30s, but 40s are noted over the w, and some of
the traditional cold spots central and e are down into the mid/upper
20s F. The northern lights are currently showing up on our n facing
camera.

Low pres over western KS will lift to eastern Nebraska today. Pres
gradient btwn this low at around 990mb and high pres ridging at
around 1032mb over New England will support increasing s to se winds
today. High clouds will be on the increase, but that won`t stop
sufficient building of mixed layer to tap stronger winds. Fcst
soundings suggest gusts of 25-30mph will become common today. In
addition, there will still be drier air aloft to mix down since
moisture feed in response to the Plains low won`t reach the area yet
today. With temps reaching the upper 50s and lwr 60s F away from
marine influences and dwpts likely falling to as low as around 20F,
RH will bottom out in the 20-30 pct range. A few spots across the w
may slip blo 20 pct. Although temps are a little shy of the typical
criteria for elevated fire wx conditions, a couple of drying days,
especially yesterday, and the expected winds gusts and low RH
support issuing a Special Weather Statement highlighting the
elevated fire wx conditions today. Given the antecedent dry air over
the area, opted to hold off any shra mention over far western Upper
MI until 22z.

&&

.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 morning for
     LSZ243>246-264>266.

  Small Craft Advisory until 5 PM EDT Saturday for LSZ244-245.

  Small Craft Advisory until 2 PM EDT Saturday for LSZ246.

  Small Craft Advisory until 11 PM EDT this evening for LSZ248.

  Small Craft Advisory until 8 AM EDT Saturday for LSZ249-250.

  Small Craft Advisory until 6 PM EDT Saturday for LSZ251.

  Gale Watch from Sunday afternoon through Monday morning for
     LSZ263.

Lake Michigan...
None.

&&

$$

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