191
FXUS63 KAPX 231926
AFDAPX

Area Forecast Discussion
National Weather Service Gaylord MI
326 PM EDT Sun Jun 23 2024

.KEY MESSAGES...

- Lingering shower chances into tonight.

- Dry start to the work week.

- Heavy rain/storm threat Monday night into Tuesday...

- Unusually chilly lows Wednesday night?

&&

.SHORT TERM /THROUGH MONDAY/...
Issued at 324 PM EDT Sun Jun 23 2024

Mid/upper level troughing continues to deepen across the northern
Great Lakes early this afternoon, made to do so by embedded
shortwaves rotating southeast around retrograding upper level ridge
building into the Desert Southwest. Lead wave, responsible for
yesterday`s significant rains and isolated severe weather, has
exited stage right as another rather robust wave digs southeast
across Lake Superior. Combination of lingering low level moisture,
diurnal trends, and cyclonic flow within overhead troughing has
kicked off a a few showers and areas of drizzle/sprinkles across
portions of the Northwoods this morning and afternoon. A bit of a
cool one for early summer, with most areas only in the upper 60s to
middle 70s.

Lake Superior wave will continue to dig southeast, cutting across
the northeast half of the area into early this evening. Building
mid/upper level heights to follow, with expanding upper level ridge
into the western Great Lakes on Monday. Attendant surface high will
build directly across our area through the day Monday.


Primary Forecast Concerns/Challenges:

Addressing lingering shower concerns into this evening. Temperature
and cloud trends through Monday.

Details:

Still expecting a few showers and perhaps a rumble or two of thunder
into this evening, especially focused across eastern upper and
northeast lower Michigan where forcing from passing wave and limited
instability/low level convergence will be maximized. Any
precipitation amounts should remain light, and nothing severe
expected. Clearing skies overnight leads into a sun-filled and
downright pleasant looking Monday...courtesy of that high pressure
mentioned above. Moderating airmass and that sunshine will help
temperatures to rebound to more normal levels, with afternoon
readings ranging from the middle 70s to lower 80s.

&&

.LONG TERM /MONDAY NIGHT THROUGH SUNDAY/...
Issued at 324 PM EDT Sun Jun 23 2024

PATTERN SYNOPSIS/FORECAST:

Progressive pattern across North America...with troughing over the
western US now, shortwave ridge over the central Canadian Prairies,
and trough over the Upper Great Lakes...with a shortwave trough to
our northwest spinning down toward Lake Superior, and another to our
northeast. Latter feature (also the one that moved over our area
yesterday/last night) has attendant anomalous 850mb low, with 996mb
surface reflection over central Ontario. Cooler, and somewhat drier,
air flooding into the Upper Great Lakes in its wake...with cold
front stretching from the aforementioned low down by Detroit and all
the way into northern Oklahoma. From here, it begins to take a
northward turn up the lee of the Rockies/High Plains as a
warm/stationary front associated with western troughing and
attendant Alberta clipper over western Canada.

Progressive pattern looks to continue through the next week...with
current troughing to give way to ridging for Monday...followed
quickly by upstream Clipper system Monday night into
Tuesday...bringing some warm advection convection to the
region...which could wreak havoc with the current temperature
forecast. A second shortwave trough slips in behind this Tuesday
night into Wednesday morning, persisting the idea of cooler and
likely drier air again...for a potentially chilly night Wednesday
night. Flow then becomes northwest/westerly aloft for a time...as
the next system develops to our west for Friday. Some signals for a
potentially anomalous surface low to develop over the central US
Friday/Saturday, which could bring some activity (and perhaps
warmth) back to our area to wrap up the workweek. Attm...a fair bit
of timing/placement differences to detangle...but general idea of a
system moving through during the Friday/Saturday timeframe certainly
looks appealing attm, particularly noting some potential for better
dynamics with this feature...though too far out to determine details
attm.

Primary Forecast Concerns:

Heavy rain/storm threat Monday night into Tuesday...Setup Monday
night appears quite favorable for one of those warm advection MCSs
that has a tendency to lead to heavy rain. Potential for a decent
cap to swing over the Upper Midwest/Upper MS Valley Monday
afternoon, which, with increasing return flow, suggests advection of
moist and weakly stable air into the vicinity of a NW-SE oriented
warm front. Question is, will this setup end up far enough northeast
to impact our area...or will the bulk of the activity end up
scraping us and settling into SW Lower MI? Quite a bit of
uncertainty attm in where this will focus the heavier rains...but
some signals (and just a general pattern recognition through
pessimistic eyes) for this to remain to our southwest, potentially
scraping parts of NW Lower. Even so, still close enough to our area
that it can`t be overlooked...particularly noting that some parts of
our area have seen as much as 3-5 inches of rain in the last 7 days
(the bulk of which has fallen in the last 48-72hrs).
Additionally...think there is potential for enough deep-layer shear
to have some concerns for storm organization, which bears watching
for severe storm concerns, in addition to the heavy rain threat.
Unclear attm how long this threat will linger into Tuesday,
particularly with respect to redevelopment...given that the 700mb
cap may slide into our region during the afternoon, such that what
instability aloft should develop may be difficult to achieve. If by
some chance we were to achieve it...then things could get much more
active Tuesday afternoon with potential for elevated storms/hail,
though this remains rather uncertain attm.

Wednesday appears quite cool behind this system...with highs over
parts of the area only reaching into the mid 60s as high pressure
settles in from the northwest going into Wednesday night. Assuming a
typical diurnal temperature swing (20-25 degrees)...would expect
lows Wednesday night, particularly over the interior higher terrain,
to drop into the lower 40s. Not impossible some localized spots
could get colder than this...though the amount of low-level moisture
that will likely still be present from the recent rainfall
(particularly pending rain Monday night into Tuesday) could prevent
lows from bottoming out as far as they otherwise could. Will keep an
eye on this going forward.

&&

.AVIATION /18Z TAFS THROUGH 18Z MONDAY/...
Issued at 1257 PM EDT Sun Jun 23 2024

Looking at periods of MVFR cigs into this evening, especially
at KAPN and KCIU...where a few light showers may also occur.
Gradual clearing trend expected tonight, with mostly sunny skies
Monday morning. Will need to watch for some patchy fog tonight,
particularly at KMBL. Gusty northwest winds go light and
variable tonight.

&&

.APX WATCHES/WARNINGS/ADVISORIES...
MI...None.
MARINE...Small Craft Advisory until 11 PM EDT this evening for
     LHZ347>349.

&&

$$

SHORT TERM...MSB
LONG TERM...FEF
AVIATION...MSB