432
FXUS63 KAPX 211912
AFDAPX

Area Forecast Discussion
National Weather Service Gaylord MI
312 PM EDT Wed Aug 21 2019

.NEAR TERM...(Through Tonight)
Issued at 238 PM EDT Wed Aug 21 2019

...Much cooler and drier air moving in...

High Impact Weather...None is expected.

Primary Forecast Concerns...Thunder chances.

The surface cold front continues to slowly trudge across northern
lower Michigan at this hour. A few showers developed along/just
ahead of this front across portions of northern lower earlier this
afternoon, even a thunderstorm near Oscoda. Just a few remaining blips
on radar across northeast lower which could linger over the next
couple of hours. Otherwise, drier air should put any remaining
showers to bed later this afternoon with waning instability and
lack of heating diminishing the cumulus field as well. A moisture
starved short wave then moves through late tonight with little to
no affect on the region with the exception of advecting in even
drier/cooler air. Lows tonight ranging from the cool mid 40s to
lower 50s.

&&

.SHORT TERM...(Thursday through Saturday)
Issued at 238 PM EDT Wed Aug 21 2019

High Impact Weather: Minimal

A trough will continue to move across the northeast CONUS/Quebec as
a jet max rounds its axis while an amplified ridge trails,
stretching from the northern Great Plains up into Hudson Bay. A
surface cyclone is expected to continue its progression NE across
Quebec and deepen slightly as it maintains healthy placement
underneath upper-level divergence before becoming mostly vertically
stacked and getting choked off from favorable temperature and
vorticity advection. As this cyclone progresses, an attendant cold
front sweeps across much of New England into the Mississippi Valley
during the forecast period. Strong surface high pressure builds
underneath subsidence at the upper-level ridge/trough inflection
point in Ontario.

Amplified flow provided between the aforementioned surface features
behind the cold front will spread cooler, dryer air southward into
the forecast area heading into the weekend. This continued CAA will
bring a taste of fall to many, keeping high temps in the upper-
60s/low-70s across northern Michigan Thursday and Friday. Low temps
those nights will also be chilly, dropping into the lower-40s and
perhaps upper-30s locally with weak surface winds and clear skies
expected overnight. As for precip, a very small chance exists
Thursday across NW lower Mi. Mostly NW flow in the low to mid-levels
will come across Lakes Superior and Michigan with potential marginal
instability as suggested by model forecast soundings. Specifically,
850mb temps near 5C overtop of lake temps near 20C creates delta Ts
of about 15C, allowing for parcels lifted from the lake surface to
contain non-zero CAPE. This could be enough to spark a few showers
across the area. Otherwise, partly cloudy skies are expected
Thursday and Friday before clearing up on Saturday. The cooler,
dryer airmass in place with subsidence overhead should inhibit rain
chances from Thursday night into the weekend.

&&

.LONG TERM...(Saturday night through Wednesday)
Issued at 238 PM EDT Wed Aug 21 2019

High Impact Weather: Rain/storm chances early next week

An amplified ridge is expected to be centered from the Great Lakes
up to James Bay at the start of the forecast period as surface high
pressure encompasses much of the eastern CONUS and Canada. A
trough approaches from the west along the international border
with a cyclone expected to form/deepen in south-central Canada as
a result of favorable upper-level support and potential transport
of warm, moist are poleward. The evolution/timing of this feature
is the main focus for the long term forecast. Model guidance
hints at a cold front passage in association with this cyclone
early next week. While this system does provide the next main
chance for rain and possibly a few thunderstorms, considerable
uncertainty still exists in regards to favorable shear,
instability, and timing to comment on specific thunder/severe
chances. Regardless, temperatures are expected to warm back up
into the upper-70s and low-80s, which would be slightly above
average for this time of year across northern Michigan.

&&

.AVIATION...(For the 18Z TAFS through 18Z Thursday afternoon)
Issued at 138 PM EDT Wed Aug 21 2019

A surface cold front is currently moving across northern lower
Michigan. Drier air will sweep in behind this front later this
afternoon and remain across the area for a few days. Perhaps an
isolated shower in the meantime but nothing significant is
expected. Cigs will be largely vfr, although an mvfr cig may slip
in at times due to over lake instability. Northwest winds will be
a bit gusty at times, especially during the afternoon hours.


&&

.MARINE...
Issued at 238 PM EDT Wed Aug 21 2019

Winds will continue to gradually pick up from the northwest this
afternoon...and will be gusty especially on Whitefish Bay/St.
Mary`s River and northern Lake Huron nearshore zones where Small
Craft Advisories are in effect for later today and tonight.
Somewhat gusty winds Thursday afternoon with gusts to between 15
and 20 knots but no headlines will be issued just yet.

&&

.APX WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LH...SMALL CRAFT ADVISORY until 8 AM EDT Thursday for LHZ346>348.
LM...NONE.
LS...SMALL CRAFT ADVISORY until 8 AM EDT Thursday for LSZ321-322.
&&

$$

NEAR TERM...AS
SHORT TERM...MR/DJC
LONG TERM...MR/DJC
AVIATION...AJS
MARINE...AS

NWS APX Office Area Forecast Discussion