Area Forecast Discussion
Issued by NWS Gaylord, MI

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FXUS63 KAPX 241725

Area Forecast Discussion
National Weather Service Gaylord MI
125 PM EDT Mon Oct 24 2016

Issued at 951 AM EDT Mon Oct 24 2016

Low pressure has reached Eastern Quebec...while a large area of
strong high pressure continues to build into the heart of the US.
In between...brisk NW low level flow and CAA continue to generate
lake effect rain showers across the Great Lakes region. Greatest
coverage is of course across Upper Michigan and Western Lower
Michigan...with another band impacting the Lake Huron shoreline of
far NE Lower Michigan around Presque Isle. All precip appears to
be solely liquid with temps generally holding in the low to mid

Little will change as we head thru the afternoon as 850 mb temps
hold between -3C and -5C...producing more than sufficient over-
lake instability for continued lake effect rain shower production.
Make need to make some minor upward tweak to POPs and areal
coverage thereof...but otherwise the overall flavor of the
forecast will go largely unchanged. Temps will only warm a few
degrees today due to ongoing CAA and mostly cloudy skies. High
temps will be in the mid 40s north to lower 50s south.


.SHORT TERM...(Today and tonight)
Issued at 314 AM EDT Mon Oct 24 2016

High impact weather potential: none.

Low-level cold advection is underway, between deep low pressure over
eastern Quebec, and high pressure building into the northern plains
and upper MS valley. Lake effect rain showers are seen downwind
of Lakes Superior and MI. This overall pattern will not
fundamentally change today or tonight. Precip trends are the main

Today/tonight...the high will advance eastward with time, pushing
into far western Ontario/WI/IN by Tue morning. A nw low-level flow
today will veer nnw tonight. The close approach of the high will
eventually relax 1000-850mb winds tonight, though we will still hang
onto cyclonically curved flow here, thanks to lake-induced troffing.
850mb temps will settle in at -3 to -5c by daybreak, stay there
today, then lower further to -4 to -7c tonight. However, MBL area
will be on the edge of the 850mb thermal trof, and thus be a little
warmer. A reasonably vigorous 500mb shortwave will dive across the
region this morning, mainly early (colder cloud tops over Superior
are a reflection of this). Otherwise, there are no forcing
mechanisms of note into tonight.

Models are rather unenthusiastic about precip in this forecast area.
That appears unrealistic, given delta Ts in the upper teens, and an
airmass that is not prohibitively dry. This is similar to the
scenario we saw 2-4 days ago, where lake effect had upticks and
downturns, but took forever to actually go away.

Will maintain sct pops in nw lower thru the period. The focus today
will be between TVC and GLR, migrating back toward TVC tonight as
winds veer a bit. Sct pops also in order in western Chip/Mack today,
diminishing tonight as the fetch becomes less favorable. Some very
small pops will also work for the Rogers City/APN area. With cooler
air moving in, might be an outside chance for a few snowflakes to
mix in over high terrain locales (like we saw early Sat morning).
Would feel better about that possibility if lake effect precip was
focused more on the GLR area tonight, deeper into the cool air. Down
by TVC, not so much. Might also warrant a snowflake mention tonight
in far western Chip/Mack, though pops will be quite small.

Outside of lake effect regimes, skies will generally be partly
cloudy. Max temps today mid 40s to around 50f. Min temps tonight in
the low/mid 30s.

.LONG TERM...(Tuesday through Sunday)
Issued at 314 AM EDT Mon Oct 24 2016

Tuesday through Wednesday night...

High impact weather potential: Minimal.

Pattern synopsis/Expected evolution: Fairly progressive pattern
continues across the CONUS for the foreseeable future with ridging
centered over the Intermountain West, leaving northern Michigan in a
transition zone as upper-level trough axis sits over the eastern
seaboard. The next feature of note is a a wave that exits the
Intermountain West by the middle of next week with cyclogenesis
ongoing, impacting portions of northern Michigan by Wednesday-

Tuesday - Tuesday night: Surface high pressure settles overhead, in
theory keeping northern Michigan precip-free despite lingering H8
air bottoming out around -4 C. Will continue the inherited dry
forecast as it`s hard go against with such paltry moisture fields.
Partly cloudy skies will be the rule, most prevalent near Lake
Michigan/Superior early in the day with more sun prevailing for the
afternoon. Temperature trends Tuesday night remain a bit of a
challenge with higher level clouds perhaps spreading in across
southwestern locations as an area of low pressure approaches, but
will continue to trend toward a cooler solution away from the big
lakes...thus have bumped min temps down a couple degrees below
guidance in those areas.

Wednesday - Wednesday night: Fairly decent guidance agreement that
by 12z Wed., low pressure is centered over central Iowa with
isentropically driven precip just off to the southwest of the CWA.
Northern edge of the precip shield is expected to ever so slowly
shift north and east throughout the remainder of the day as the
system`s center tracks toward Chicago Wed. afternoon and eventually
into southern MI by Thu. morning. Cool enough air through the column
certainly could support a mix of rain and snow, despite surface
temps just above freezing, in the 33-35 degrees across portions of
northern Lower into eastern Upper Wednesday night. For both
geographic locations, would expect any mixed precip to be limited to
inland locations, away from the big lakes prior to low-mid level
temperatures warming above 0 C by early Thursday morning as the sun
rises and the system continues to shift east.

Extended (Thursday through Sunday)...

Low pressure continues to shift off to the east throughout the day
Thursday with scattered rain showers lingering across a portion of
the area through the afternoon hours. Could continue to see a few
snowflakes mix in across eastern Upper early Thursday morning before
transitioning to all liquid as an October diurnal cycle would render.
Several additional precip chances continue through the remainder of
the period, both of the lake effect and synoptic system varieties.


.AVIATION...(For the 18Z TAFS through 18Z Tuesday afternoon)
Issued at 125 PM EDT Mon Oct 24 2016

Scattered lake effect rain showers will continue to impact much of
Northern Lower Michigan into early evening...and will gradually
diminish in areal coverage during the rest of the night as high
pressure and drier air build into the region. Overall conditions
will remain VFR...although CIGS may briefly drop to MVFR within
heavier rain showers. N/NW winds will continue to gust to 15 to 25
kts this afternoon into early evening...diminishing to 10 kts or
less overnight.


Issued at 314 AM EDT Mon Oct 24 2016

Gusty nw/nnw winds continue today, between low pressure in
eastern Canada and high pressure in the northern plains. Winds
relax tonight, as the high moves closer. Advisories already issued
for all waters into early evening. After a relatively quiet
Tue/Tue night, stronger east to se winds may develop on Wed.


LH...SMALL CRAFT ADVISORY until 8 PM EDT this evening for LHZ345>349.

LM...SMALL CRAFT ADVISORY until 8 PM EDT this evening for LMZ323-341-

LS...SMALL CRAFT ADVISORY until 8 PM EDT this evening for LSZ321-322.



LONG TERM...Gillen
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