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615
FXUS63 KMQT 081149
AFDMQT

Area Forecast Discussion
National Weather Service Marquette MI
749 AM EDT Sat Jun 8 2024

.KEY MESSAGES...

- A few stronger storms capable of small hail and gusty winds
  are possible this afternoon, mainly east-central.

- Light rain showers are expected on Sunday with breezy north
  winds gusting up to 20-30 mph, especially over the eastern
  U.P.

- High pressure brings a brief dry period for Sunday night
  through Tuesday.

- Periods of showers and storms are expected mid to late next week.

- Below normal temperatures are forecast through early next
  week, but a warming pattern will follow through next weekend.

&&

.SHORT TERM /TODAY/...
Issued at 500 AM EDT Sat Jun 8 2024

Current radar mosaic is beginning to light up a bit to the west as
rain showers enter the area with the next shortwave.  These rain
showers will continue their eastward propagation into central Upper
Michigan through the course of the morning and eventually the
eastern third of the forecast area by this afternoon.  By this
afternoon, a cold front combined with lake breezes could initiate
thunderstorm development across the central and east quadrants. With
limited instability, storms are not expected to reach severe levels.
 Nonetheless, some could become strong at times with pea-sized hail
and gusty winds with some SBCAPE values in the 500 to 1000 J/kg
range and bulk shear around 30-40 kts.  Meanwhile, temperatures
today will generally top off in the upper 60s/low 70s with west-
northwest winds of 10 to 15 mph by this afternoon.

&&

.LONG TERM /SUNDAY THROUGH FRIDAY/...
Issued at 527 AM EDT Sat Jun 8 2024

The extended forecast period begins tonight with an elongated trough
extending from Alberta to Quebec. This setup evolves into an omega
shape by the start of the work week with positively tilted ridge
over the Upper Mississippi Valley stuck between a trough over the
Lower Great Lakes and another trough over Saskatchewan. As this
pattern shifts east next week, the western trough passes over the UP
later in the day Tuesday into Tuesday night. Meanwhile another
trough over the Pacific Northwest is making landfall into British
Columbia. This far western trough propagates east along the Canadian
Prairie Provinces to the Upper Great Lakes for mid to late next
week, sending two shortwaves over the area.

Starting tonight, the oblong trough stretching across much of the
US/Canada border begins to separate. Isentropic ascent and PVA will
continue some light showers overnight, highest PoPs in the Keweenaw,
north central, and eastern Upper MI. A few isolated storms are
possible over south central before midnight, however no severe
weather is expected as instability drops off as daytime heating ends
and bulk shear diminishes below 30 kts per the 6/8 0Z HREF mean.
Lows are expected in the mid to upper 40s.

Chances for showers continue on Sunday as a cold front drops south
of the UP. Cool north flow behind the front looks to keep temps
below normal throughout the day in the 50s to mid 60s, warmest in
south central Upper MI. That said, those along the eastern Lake
Superior shores may never get out of the 40s all day. Northerly
upslope flow with an uptick in moisture noted in the model soundings
and PWATs increasing from around 0.7" to 0.9" will support mostly
cloudy skies and light rain showers through the day. As high
pressure begins to build in from the northwest, the UP dries out by
the evening. A ~40 kt LLJ passing over the eastern CWA will help
yield some breezy gusts up to 25-30 mph. Lows are forecast in the
40s, however upper 30s are possible in the interior east where drier
air intrudes faster and we are able to clear out sooner.

High pressure keeps the weather dry through Tuesday morning. Temps
warm up from the weekend into the 60s under sunny skies on Monday.
With increased mixing to around 900-800mb, higher mixing over the
interior west, min RHs are expected in the mid 20s to mid 30s (drier
away from the lakeshores and in the interior west). Gusts will be
stronger over the east where RHs are not as low; this does flirt
with borderline elevated wildfire conditions.

The next round of showers and storms moves in from the west on
Tuesday as a mid level trough moves east from Manitoba to Ontario.
The shortwave rotating around it will support a sfc low tracking
east along the international border from Manitoba to just north of
Lake Superior into Tuesday night. The cold front tracking east with
it will yield showers and possible storms into Tuesday night. While
bulk shear is expected ~40kts, little CAPE leaves severe potential
low (<10%). Shortwaves arriving mid to late next week leave
potential for additional shower and storms, however with the current
spread in timing among the guidance, opted to leave NBM PoPs as is
for now.

&&

.AVIATION /12Z TAFS THROUGH 12Z SUNDAY/...
-- Changed Discussion --
Issued at 748 AM EDT Sat Jun 8 2024

Despite rain showers overspreading the TAF sites from west to east
today, conditions will remain at VFR levels at all TAF sites.  Will
carry mention, though, of thunderstorms at SAW this afternoon from
18-21Z as a cold front combines with lake breezes.  Some of the
storms could become strong at times with small hail and gusty winds
and abrupt cig/vsby restrictions.
-- End Changed Discussion --

&&

.MARINE...
Issued at 527 AM EDT Sat Jun 8 2024

West winds are expected to remain at or below 20 kts through Sunday
morning. Winds increase to 20 to 25 kts, veering northwest, by
Sunday afternoon over the east half of the lake as a LLJ passes
overhead. There is a 40-60% chance for higher observing platforms
over the eastern 3rd of the lake to see gusts approach 30 kts on
Sunday. As high pressure builds in from the northwest into Monday,
winds fall back below the 20 kt threshold. The next potential for
winds to exceed 20 kts is Tuesday into Wednesday when a low pressure
system tracks north of Lake Superior, but chances of winds
exceeding 20 kts are low (<30%) given the stability over the lake.

&&

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

&&

$$

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