552
FXUS63 KAPX 222012
AFDAPX

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

.KEY MESSAGES...

- Rain continues into tonight; cooler Monday

- Rain chances return Tuesday into Wednesday

- Dry weather, above average temperatures expected into this
  weekend

&&

.SHORT TERM /THROUGH MONDAY/...
Issued at 410 PM EDT Sun Sep 22 2024

PATTERN SYNOPSIS/FORECAST:

General surface troughing has been tracking east today...reaching
Drummond Island southward generally toward Saginaw Bay. Surface
low/wave along the boundary well to our south over SW Lower MI.
Rainfall generally more stratiform south of a line from PZQ to CAD
to FFX where right entrance region jet dynamics are playing a bigger
part in broader synoptic forcing. Some embedded heavier bands of
precip where some mesoscale enhancement, most likely in the form of
deformation as NW flow behind the boundary diverges a bit as it
reaches the boundary (broadly northerly surface flow, though, in
the wake of the low), and/or potentially some gravity waves and/or
fgen. Rainfall is a bit more convective from FKS toward ANJ/DRM
along/ahead of the 850mb trough; additionally...better PVA with the
primary PV anomaly located up here...and some better rainfall rates
at times (ANJ has picked up a little over six-tenths in the last few
hours with some of these convective showers). Some clearing noted to
our northwest in the wake of the 850mb trough, though some diurnal
and/or lake streamer clouds noted per visible satellite, as temps
aloft cool into the single digits.

Expecting surface trough as well as 850mb trough to exit stage right
through the night, likely to our east by morning. Showers and storms
to continue to depart early this evening with things quieting down
tonight weather-wise. Some potential for waterspouts over the waters
as we cool off aloft. Good shot of north flow induced small craft
advisory criteria through tonight, especially for Lake Michigan and
Whitefish Bay; less confidence attm in reaching this for Presque
Isle zone, but have left the small craft up for now. Also think some
fog could develop overnight if we decouple enough, given the added
moisture from today`s rainfall (guidance soundings suggest
decoupling will take place, though not sure winds will totally die
off overnight); otherwise could be some annoying low stratus around.
High pressure settles in in the wake of this for Monday...with temps
a bit on the cool side due to prevailing northerly flow, though
could be a little warmer than normal if it ends up sunny enough.
Will have to keep an eye on winds/waves for Monday as well, as there
is some potential for slight northeasterly flow to generate small-
craft-advisory conditions for areas south of Thunder Bay in
particular on Monday...though it appears marginal attm whether or
not it will be able to get into our nearshore zones.

&&

.LONG TERM /MONDAY NIGHT THROUGH SUNDAY/...
Issued at 410 PM EDT Sun Sep 22 2024

Pattern Synopsis:

Southern stream troughing will continue to lift across the
Mississippi Valley and over the Ohio Valley/southern Great Lakes on
Tuesday. Meanwhile, the pattern upstream looks to amplify greatly
heading into the middle of the week with northern stream troughing
digging sharply down the Great Plains towards the Gulf Coast and
expansive ridging encompassing most of the western CONUS. Said
troughing is expected to get cut off from the main flow, pivoting
over the southern Mississippi Valley through the remainder of the
week as aforementioned ridging folds northern over the Great Lakes.
To further complicate the pattern, a potential tropical cyclone may
make landfall across the Gulf Coast later this week, likely aiding
to build ridging across much of the country to its north through the
end of the period.

Forecast Details:

Rain chances return Tuesday into Wednesday -- After a break from
showers Monday night, rain chances will return to parts of northern
Michigan on Tuesday as a weak cyclone looks to trek across the
southern Great Lakes. Uncertainty in strength and track will impact
how far north and west rain chances extend across the area,
especially Tuesday afternoon into Wednesday morning. Current
confidence is that the best chances for rain will come along and
southeast of a line from Manistee to Alpena, with lesser chances
extending northwest of here. With model guidance differing in track
and strength of precip, belief is to lean on a weaker/drier solution
for two reasons: potential precip working against recent extended
period of dry conditions, and relatively weak forcing potentially
resulting in a solution that is further southeast with the track of
the system. Latest trends in model guidance will be monitored
closely.

Dry weather, above average temps -- After rain chances depart on
Wednesday, another extended period of rain-free weather may be in
store for the area for the second half of the week and through this
upcoming weekend. If ridging materializes as expected, high pressure
would build across the region and keep dry weather in place through
the extended forecast. With little forcing, no significant frontal
passages, and therefore no substantial airmass change, daytime highs
in the 70s with overnight lows upper 40s and 50s could stay in place
across northern Michigan through the period and beyond. These
temperatures would be around 5-10 degrees warmer than average for
the end of September.

&&

.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 LHZ347-348.
     Small Craft Advisory until 11 AM EDT Monday for LMZ323-342-
     344>346.
     Small Craft Advisory until 7 AM EDT Monday for LSZ321-322.

&&

$$

SHORT TERM...FEF
LONG TERM...DJC
AVIATION...FEF