414
FXUS63 KAPX 201415
AFDAPX

Area Forecast Discussion
National Weather Service Gaylord MI
1015 AM EDT Sat Jul 20 2024

.KEY MESSAGES...

- Isolated to scattered afternoon and evening thunderstorm
  chances today thru Tuesday, especially across eastern upper
  and northeast lower.

- Shower and thunderstorm chances increase as we head into mid-
  week.

&&

.UPDATE...
Issued at 1014 AM EDT Sat Jul 20 2024

Current forecast largely remains on track with no major changes. A
few storms have already initiated across northern Lake Superior in
the vicinity of a cold front slowly working south across the region.
Isolated to scattered showers and storms look to move into the
eastern U.P. by early afternoon, supported by 500-1,000 J/kg MLCAPE.
Chances will gradually make their way into northern lower by late
afternoon/evening and taper off into tonight. Severe storms are not
anticipated at this time.

&&

.SHORT TERM /THROUGH TONIGHT/...
Issued at 352 AM EDT Sat Jul 20 2024

Pattern/synopsis: High pressure extends e-w over the southern
Great Lakes. A cold front also extends e-w to our north, about
on the latitude of Thunder Bay ON. This front will continue to
drop south, reaching eastern upper MI by midday, and our
southern zones by mid-late evening.

Forecast: Not a lot of cloud cover early this morning, mainly
just a little cirrus in northern lower MI. There`s more in the
way of clouds to the north, over northern Lk Superior and
surrounding parts of Canada. This will push southward, and
clouds will increase in eastern upper MI this morning. The
primary band of enhanced moisture trails the surface front.
Instability is minimal presently, but with diurnal heating,
MlCape values will reach 500-700j/kg in eastern upper MI by
early afternoon. Forcing isn`t terribly impressive, but lake
breezes should be enough to get a few cells going. We will
start the morning dry, but by midday a small chance for precip
pops up in central/northern Chippewa Co. Pops get a bit higher
into the afternoon and early evening, as the moist band slowly
sags south across eastern upper MI and into far northern lower
MI. Shear is negligible, and instability is insufficient for a
svr threat on its own. But at least a few thunderstorms are
expected.

Tonight: surface instability will tend to wane as diurnal
heating is lost. Pops gradually decrease as the moist band makes
southward progress into northern lower MI, mainly north of M-72
thru 06Z. Overnight, surface-based instability is over, but an
elevated mixed layer persists, with relatively steep lapse rates
aloft. MuCape values overnight of 200-300j/kg are seen. Not out
of the question for a stray, random elevated shower late
overnight in northern lower MI. Meanwhile, eastern upper MI will
see decreasing clouds tonight.

Max temps today upper 70s to mid 80s. Lows tonight lower 50s to
lower 60s.

&&

.LONG TERM /SUNDAY THROUGH FRIDAY/...
Issued at 352 AM EDT Sat Jul 20 2024

No major changes to the ongoing forecast with guidance continuing to
hold the strong upper level ridge well southwest of the region while
keeping shallow troughing across the Great Lakes over the next
several days. Weak, slow moving embedded disturbances in combination
with the development of afternoon lake breezes could spark isolated
late day and early evening showers or storms through Tuesday. The
best chance of any convective activity looks like it will be across
eastern upper and northeast lower. Better shower and storm coverage
is then expected Wednesday into Thursday due to the combination of
somewhat increased low level moisture and perhaps a more defined
slow moving upper level wave. Very similar temperature pattern
expected over the next few days with highs mainly in the upper 70s
and low 80s (even a few mid 80s Tuesday) and lows in the upper 50s
and low 60s. Looking farther ahead, extended guidance is trending
toward the eventual northeast expansion of the upper level ridge.
This setup would allow for noticeably warmer and more humid
conditions to develop across the region next weekend.

&&

.AVIATION /12Z TAFS THROUGH 12Z SUNDAY/...
Issued at 641 AM EDT Sat Jul 20 2024

VFR.

A touch of early morning fog at MBL, but not as much as
yesterday, and do not expect it to last past 12Z in any case.
By midday into the afternoon and early evening, perhaps some
VCSH possible at CIU and then PLN, as a cold front drops in from
the north.

Light winds.

&&

.APX WATCHES/WARNINGS/ADVISORIES...
MI...None.
MARINE...None.

&&

$$

UPDATE...DJC
SHORT TERM...JZ
LONG TERM...AJS
AVIATION...JZ