371
FXUS63 KAPX 172302
AFDAPX

Area Forecast Discussion
National Weather Service Gaylord MI
702 PM EDT Tue Jun 17 2025

.KEY MESSAGES...

- Heavy rain and severe weather threat both on the table for
  Wednesday into Wednesday evening.

- Periodic shower/storm chances and a warming trend expected
  into next week.

&&

.SHORT TERM /THROUGH WEDNESDAY NIGHT/...
Issued at 230 PM EDT Tue Jun 17 2025

Pattern Synopsis/Forecast:

Zonal mid and upper level flow found across the northern Lake early
this afternoon, with embedded rather weak shortwave racing east
across eastern Lake Superior. Low pressure tied to this wave itself
working east into eastern Ontario, with its attendant cold front
slicing across northeast lower Michigan.

Cold front will quickly clear the area later this afternoon, looking
to eventually stall out across central/southern Michigan tonight and
Wednesday morning. Baroclinic response will intensity along this
front tonight into Wednesday as shortwave trough rotates out of the
central Plains. This will help drive low pressure across lower
Michigan later Wednesday/Wednesday night...setting the stage for
potentially rather active weather across the Northwoods.

Primary Forecast Concerns:

Shower/storm evolution Wednesday and Wednesday night...to include
heavy rain and severe potential.

Details:

As mentioned, front expected to clear the area this afternoon, with
weak high pressure to follow resulting in a dry overnight. Could see
some fog develop later tonight, especially in those areas that
received some rain today.

Interesting and rather challenging situation unfolding for Wednesday
as strong surge of elevated warm and moist advection quickly spread
across the region. Impressive moisture advection (precipitable water
values up and over 1.50 inches) and what looks to be elevated
frontogenetical response...both within favorable mid and upper level
support, should drive an expanding area of showers and embedded
thunderstorms northeast into at least sections of lower Michigan.
Expecting some impressive and efficient rain makers given impressive
deep moisture through the vertical and juxtaposition of deep lift.
Those high rain rates sets up the potential for significant rain
totals...likely up and over an inch...especially where cell training
occurs. Although latest Weather Prediction Center Day 2 Outlook has
all of our area in a marginal risk for excessive rain Wednesday into
Wednesday evening, juxtaposition of deepest moisture convergence and
expected fgen response suggests areas south of M-72 (perhaps even
south of M-55) stand the best risk for significant rain totals.

Per the northern Michigan usual, severe threat highly dependent on
northward propagation of moisture rich warm sector. Definitely two
distinct "scenarios" with regards to this northward extent...with
some guidance featuring more shortwave phasing and an attendant
deeper and more north passage to the surface low response. This in
turn drives the warm sector into at least southern sections of our
area, setting us up for more surface rooted instability and a more
veered low level environment...both within a increasingly deeply
sheared vertical column. Above definitely supports a severe weather
concern, supporting all modes of severe weather...including a
tornado potential. However, the less aggressive solutions feature a
much less aggressive northward push to the warm sector as weaker low
pressure passes across central/southern Michigan...keeping the vast
majority of severe concerns to our south. This latter scenario is
definitely more favored given time of year and lack of a better
thermal gradient to drive deep surface low development. Latest Storm
Prediction Center Day 2 convective outlook kinda taking the middle
ground...keeping marginal wording for severe weather across most of
northern lower Michigan...with slight risk wording just clipping
Gladwin County. Definitely something to monitor as we head into
Wednesday.

&&

.LONG TERM /THURSDAY THROUGH TUESDAY/...
Issued at 230 PM EDT Tue Jun 17 2025

Pattern Synopsis/Forecast:

Main feature of interest for the extended period is fairly well
agreed upon expansion of subtropical ridging/heat dome across the
eastern Conus this weekend into early next week. Conceptually,
expected placement of this ridge should not only allow some true
summer heat to expand north into northern Michigan, but should put
the northern Lakes within favorable zone for ridge running
convective complexes.

Primary Forecast Concerns:

Temperature trends and additional shower/storm concerns.

Details:

Low confidence forecast through the extended, especially centering
on shower/storm chances. While Wednesday system will have exited
stage right by Thursday morning, lingering baroclinic axis and
additional energy along leading edge of expanding mid level ridge
could drive additional shower and thunderstorm chances at times
Thursday on through the weekend. Definitely do not feel this whole
period with be a washout by any means, with shower and thunderstorm
concerns likely relegated to short time windows as waves pass across
the region. Given moisture and expected instability gradient, will
need to monitor for additional heavy rain and severe storm concerns.
Trends continue to support expanding heat into the region early next
week, with pattern recognition supporting highs well up into the 80s
and 90s Sunday through Tuesday. Low level moisture should also be
fairly abundant, making it feel even more uncomfortable and even
perhaps pushing us into heat advisory criteria. Will again need to
watch for storm complexes to ride the ridge ridge/trough interface
into the northern Lakes, although that threat may pivot north out of
our area for a time as heat dome further expands into the region.

&&

.AVIATION /00Z TAFS THROUGH 00Z WEDNESDAY/...
Issued at 701 PM EDT Tue Jun 17 2025

VFR conditions are expected at northern Michigan TAF sites through
the majority of the issuance period. Patchy BR/FG may be possible
tonight across parts of the area that saw rain/storms earlier today,
which brings the potential for lowered VSBYs at APN. However,
current confidence is not high enough to include explicit mention in
the APN TAF at this time. Weak/calm winds are in store tonight,
increasing to 5-10 kts out of the east-southeast on Wednesday. Rain
chances will increase from southwest to northeast on Wednesday,
especially after 16Z. Steadiest rainfall across northern lower
Michigan is currently expected after the end of the issuance period
(00Z Thursday). Drops to MVFR conditions will be possible, but not
currently anticipated. Embedded thunderstorms will also be possible,
most notably at MBL and TVC, but confidence is currently too
low to include in the TAF at this time.

&&

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

&&

$$

SHORT TERM...MSB
LONG TERM...MSB
AVIATION...DJC