Area Forecast Discussion
Issued by NWS Gaylord, MI

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FXUS63 KAPX 220710
AFDAPX

Area Forecast Discussion
National Weather Service Gaylord MI
310 AM EDT Mon May 22 2017

.NEAR TERM...(Today through Tonight)
Issued at 311 AM EDT Mon May 22 2017

...Cool-ish and damp-ish...

High impact weather potential...none.

Mature surface low continues to spiral away nw of Thunder Bay
Canada. Occluded front is now well downstream, and post-frontal sw
low-level flow is well established. We had been beneath the mid-
level dry slot, but that is also departing eastward, with expanding
clouds and cooling cloud tops here and upstream. Very light radar
returns, evidence of sprinkles but nothing more, are seen over far
northern Lake MI and surroundings. More vigorous showers are seen
upstream. Precip trends are the main concern.

Today...one prominent shortwave rotating around the closed low will
pivot ne-ward across northern MI this morning. Areas of showers
presently in northern WI are associated with this wave. Forcing will
be sharpest across eastern upper MI, which is also where the deepest
moisture lies (closest to the upper low). Morning pops will range
from likely in far nw lower and eastern upper MI, to negligible in
the se. For the afternoon, sct showers will continue to cycle
eastward in close proximity to the 500mb low. Northern lower will
see enough post-wave subsidence to see those showers end and partial
clearing result, especially south of M-32. Temps are still on the
cool side aloft, though, and some meager instability may result.
SbCape values are progged up to 200j/kg down in the TVC/CAD area. No
obvious triggers around (too much synoptic sw wind for lake
breezes), but a bit of a vort max is crossing central lower MI, and
our low-level is backing ahead of a better shortwave digging toward
Iowa/southern MN. Will hold off on any pops thru 00z (though will
break out some precip immediately thereafter).

Healthy max temp range, thanks to plenty of clouds north and
eventually some partial sunshine south. Highs from the low/mid 50s
eastern upper, to the mid 60s in the far se.

Tonight...weak surface low will spin up in Iowa, ahead of digging
shortwave from the larger upper low to our north. Backing low-level
flow ahead of the low result in some 850mb theta-e advection into
central lower MI. This is in an environment with MuCape values of
100-200j/kg. This all will result in sct showers transiting southern
sections of the forecast area, primarily near and south of M-72.
There will also still be sct showers hanging around eastern upper MI
in the 1st half of the night, due to the nearby upper low. The upper
low will more bodily lift out to the ne overnight, and pops will end
in eastern upper with partial clearing north of M-32. This will be
conducive to some patchy fog overnight in northern sections.

Min temps near 40f in eastern upper MI to mid/upper 40s in the south.

&&

.SHORT TERM...(Tuesday through Wednesday)
Issued at 311 AM EDT Mon May 22 2017

...Cool and showery conditions continue...

High impact weather potential: Slight chance of thunder Tuesday
afternoon, mainly south of M-32.

Pattern forecast: Longwave troughing is expected to encompass the
eastern half of the CONUS by midweek as ridging builds across the
West Coast into southwestern Canada. Main feature controlling our
weather will continue to be stationary closed low pressure aloft,
bringing occasional showery periods as several waves of energy dive
out of Canada and pinwheel around the parent low. At least a brief
reprieve from wet weather arrives toward the end of the work week as
high pressure settles in before additional rain chances arrive over
the Memorial Day weekend.

Primary forecast challenges/concerns: Shower chances throughout the
forecast period and slightly below normal temperatures.

A rather cool and damp pattern is expected throughout the forecast
period with several waves of showers expected to make their way from
south to north across northern Michigan. Neither Tuesday or
Wednesday are expected to be complete washouts as the timing of
shower chances revolves around several shortwaves rotating around
aforementioned cutoff low pressure aloft. As it stands right now, it
looks like the best chance for more widespread showers will be
Tuesday night; however, the pattern as a whole isn`t one where you`d
expect widespread precip over the entire area for an extended period
of time...so it`s likely that some will do "better" with respect to
rainfall amounts than others. Shower chances continue Wednesday, but
again is expected to be more so of a hit or miss type scenario
rather than widespread appreciable rainfall.

High temperatures a couple of degrees below normal on Tuesday
ranging from near 60s north of the bridge and through the 60s south.
Cooler temps Wednesday with widespread readings between the upper
50s to low 60s.

&&

.LONG TERM...(Wednesday night through Sunday)
Issued at 311 AM EDT Mon May 22 2017

High impact weather potential: Minimal.

Showers remain possible Wednesday night through at least the first
half of Thursday before high pressure settles atop the Great Lakes,
at least briefly. Uncertainty increases over the upcoming Memorial
Day weekend as ensemble guidance spreads significantly in terms of
rain potential. Worth monitoring as we get closer for periods of wet
weather to impact any kick off to summer outdoor activities, but at
the very least a return to normal temperatures looks to prevail.

&&

.AVIATION...(For the 06Z TAFS through 06Z Monday night)
Issued at 1118 PM EDT Sun May 21 2017

Low pressure was over western Lake Superior will lift into Ontario
Monday, while increasingly deeper low level moisture in colder
air, advects in across nrn Michigan. Skies will be cloudy for much
of the TAF period, with CIGS lowering into MVFR overnight and into
Monday morning. Moisture becomes deep enough late tonight and into
Monday morning ahead of a disturbance aloft to possibly bring some
light showers to mainly the NW lower airports. Skies will then
gradually turn VFR through Monday afternoon, with some partial
clearing and more gusty SW winds.

&&

.MARINE...
Issued at 311 AM EDT Mon May 22 2017

Somewhat gusty sw winds will continue today, as low pressure
remains just north of Superior. Advisory-level conditions are
expected on Lake MI and in the Straits. Lighter and more variable
winds are expected to develop tonight and persist into Tuesday
night.

&&

.APX WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LH...SMALL CRAFT ADVISORY until 8 PM EDT this evening for LHZ345.
LM...SMALL CRAFT ADVISORY until 8 PM EDT this evening for LMZ323-341-
     342-344>346.
LS...NONE.
&&

$$

NEAR TERM...JZ
SHORT TERM...MJG
LONG TERM...MJG
AVIATION...SMD
MARINE...JZ



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