983
FXUS63 KAPX 221746
AFDAPX

Area Forecast Discussion
National Weather Service Gaylord MI
146 PM EDT Sun Sep 22 2024

.KEY MESSAGES...

- Showers and some storms return today and tonight, with locally
  heavy rain in nw lower MI

- Cooler wx this upcoming work week

&&

.UPDATE...
Issued at 955 AM EDT Sun Sep 22 2024

SW 120+kt upper level jet just to our west/northwest...between
approaching trough axis stretching from Manitoba down into the
central Plains...and ridge axis still trying to hang on over the
Great Lakes. Greatest PVA focused to our north with a weak boundary
and some attendant scattered showers/storms this morning over the
central UP just behind the surface front, actually. Better jet-level
forcing, deep moisture (pwats approaching 2in), and fgen noted over
SW WI into central Lake MI where a plume of better rainfall has been
slowly moving northeastward over the last several hours, after some
intriguing backbuilding over southern WI per IR/WV imagery.
Relatively stagnant to mildly east-ish/variable winds over Northern
Michigan this morning with this low level moisture, combined with
weak synoptic subsidence over the EUP has led to annoying fog
persisting from parts of the Lake Huron coastline of NE Lower...up
into the EUP...but will expect some improvement in
visibilities/ceilings as the front moves in to start generating
showers/storms over the next few hours. Do expect the blob of better
rainfall to our southwest to continue to creep northeastward through
the remainder of the morning into this afternoon...as additional
rain showers continue to develop over northeast Lower. Suspect best
potential for heavier rains will hang on over northern Lower
compared to the EUP...though not impossible some better rainfall
rates could be found under any convective activity that tries to
slide through up there. Will watch for embedded thunder across
northern Lower as well.

&&

.SHORT TERM /THROUGH TONIGHT/...
Issued at 342 AM EDT Sun Sep 22 2024

Pattern/synopsis: Cold front slowly moving across western upper
MI and central WI. Convection is occurring ahead of the front,
mostly from ne WI and points s and w. The front crosses northern
MI this afternoon and early evening.

Forecast: Marine fog/stratus continues to cover parts of ne
lower and eastern upper MI, especially near Lk Huron. That seems
likely to last until this afternoon, when winds veer nw to n
behind the cold front.

Mid-high clouds cover much of northern lower MI (excepting the
ne lower MI coast), not so much eastern upper MI yet. As we move
thru the morning, the boundary is progged to sharpen, and
precip should gradually shift behind the front. That will slow
eventual precip onset, though some (mostly light) showers will
occur in nw lower and eastern upper MI. A band of more
substantial precip, supported by lifting moist and somewhat
unstable air, across the frontal boundary. Lapse rates are not
especially steep, and MuCape values are only around 200-300j/kg.
That will support thunder, but severe is not expected. But a
narrow axis of PWAT values exceeding 1.5" will contribute to
healthy rainfall rates at times. Have QPF today of 0.50-1.00"
across a good portion of nw lower MI. This won`t result in hydro
problems.

Precip continues eastward tonight, and by dawn only ne lower MI
has a chance of lingering showers. Northerly breezes kick in
behind the front late today and tonight, and much cooler temps
press in (aided by rain-cooled temps). QPF looks to be lower
tonight, as high as 0.50" near Saginaw Bay.

Max temps today range from mid-60s eastern upper MI, to near 80f
near Saginaw Bay. Lows tonight in the 40s to near 50f.

&&

.LONG TERM /MONDAY THROUGH SATURDAY/...
Issued at 342 AM EDT Sun Sep 22 2024

Pattern Synopsis and Forecast:

Current midlevel flow over the Great Lakes region continues active
weather at times as upstream troughing over Northern Minnesota
returns showers and storms to the CWA. Northern branch flow
currently over Canada will push southward, resulting in a cooler
air mass to settle into the region this week.

Aformentioned troughing currently overhead will be centered over
Southern Hudson Bay at the start of the long term. A secondary weak
trough riding along southern branch flow will moves through the
Midwest this Tuesday, continuing chances for an additional round of
showers as it passes the CWA. Conditions then turn drier for the
second half of the work week as upstream riding support surface high
pressure this Wednesday through the remainder of the long term.

Primary Forecast Concerns/Key Messages:

Showers linger this Monday and Tuesday. Cooler air settles into
Northern Michigan this week: No impactful weather is expected
through the entirety of the forecast period. Only active weather
will be from a few scattered showers this Tuesday as
aformentioned southern branch embedded troughing moves across
the CWA. Ensembles depict little if any measurable precipitation
am most forcing will be along the Ohio Valley. Most focus for
the long term period is a cool Canadian air mass returning
climatologically average temperatures this week. Highs will
remain in the upper 60s to low 70s starting this Monday through
the entire work week while overnight lows will remain around 50
degrees.

&&

.AVIATION /18Z TAFS THROUGH 18Z MONDAY/...
Issued at 146 PM EDT Sun Sep 22 2024

Front dragging through the region today; expecting southern end of
this to slow up near MBL this afternoon with winds holding easterly
for a bit longer there. Ultimately expecting all sites to transition
to NW and N winds this afternoon behind the front, though could
become light and variable at times esp overnight. Some LLWS around
2kft esp near CIU (explicitly mentioned in TAFs); wind shift aloft
from SW to NNW will lag behind surface wind shift by a few
hours...and expecting decoupling overnight to allow for lighter
surface winds. SHRA/RA expected at all sites through evening;
greater potential for TS for CIU/PLN though not impossible
elsewhere. Rain exits overnight, with potential for low stratus
and/or fog to develop...though a bit less confidence in fog
development if we stay mixed up into just a low stratus deck
overnight. Improvements expected for Monday morning.

&&

.APX WATCHES/WARNINGS/ADVISORIES...
MI...None.
MARINE...Small Craft Advisory from 8 PM this evening to 2 AM EDT Monday
     for LHZ346>348.
     Small Craft Advisory until 11 AM EDT Monday for LMZ344>346.
     Small Craft Advisory until 7 AM EDT Monday for LSZ321-322.

&&

$$

UPDATE...FEF
SHORT TERM...JZ
LONG TERM...SJC
AVIATION...FEF