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afdapx

Area forecast discussion
National Weather Service Gaylord Michigan
101 PM EDT Tue Oct 22 2019

Update...
issued at 1009 am EDT Tue Oct 22 2019

Vertically stacked low pressure currently centered over Western
Lake Superior continues to make its presence known across northern
Michigan. After dry slotting overnight and even a good amount of
clear skies across the region, clouds and showers continue to
become more numerous this morning, especially west of I-75. Expect
this trend to continue, although with another round of
increasingly gusty southwesterly winds through much of the
remainder of the day.

Adjustments this morning include relatively minor spatial and
temporal tweaks of ongoing headlines, along with pops and winds
through the remainder of the daylight hours.

&&

Near term...(today through tonight)
issued at 331 am EDT Tue Oct 22 2019

..windy and showery...

High impact weather potential: Lakeshore flooding/beach erosion
concerns continue through Wednesday, mainly on Lake Michigan.

Pattern synopsis and forecast:

A vertically stacked low pressure is situated over northern
Wisconsin with broad cyclonic flow across the Midwest and Great
Lakes region. This system will continue its northward progression
into Ontario through Wednesday. Continued gusty winds will pose
the greatest impact in terms of more Lakeshore flooding and beach
erosion concerns on Lake Michigan. Cold air advection will usher
in cooler air today across northern Michigan as the low pressure
continues its northward progression into Ontario. 800 mb temps falling
to around -2c by this evening/overnight, leading to increased lake
induced instability, which combined with deeper moisture rotating
through the back side of the system should be plenty of support to
produce additional showers through much of the remainder of the
day into tonight and possibly into Wednesday morning (most
numerous will be downwind of Lake Michigan/Superior in west-
southwest flow). Continued showers downwind of the lakes early
Wednesday should gradually give way to drier conditions as weak
warm air advection slowly takes over. High temperatures will range
from the upper 40s to low 50s area-wide, although with
cloudy/rainy/windy conditions, will likely feel several degrees
cooler than that, while overnight temperatures will drop into the
upper 30s to low 40s.

&&

Short term...(wednesday through thursday)
issued at 331 am EDT Tue Oct 22 2019

..winds diminish Wednesday lake effect precipitation through
Thursday...

High impact weather potential...do we get scattered slick spots
Thursday night/Friday morning? Very low chance.

Pattern synopsis/forecast...current storm system by Wednesday
morning (12z/wed) has moved to just west of James Bay. The system,
itself, has begun the filling process as the low has become
vertically stacked. However, there are sfc and upper level troughs
that are rotating around the low that help to "funnel" energy over
the upper Great Lakes region through the next 48 hours. Model agree
with the overall precipitation pattern the rain or rain/snow is
mainly over Upper Michigan (especially east upper) through the day on
Wednesday with lake effect rain over north lower. Wednesday evening, a
decent amount of energy (a jet streak (70+kts) at 500 mb) rotates
into the base of the 500 mb trough and begins to help sharpen the
trough with the sfc trough also beginning to sharpen the baroclinic
zone near the sfc. This begins to enhance the le precipitation as
the jet streak moves east. Thursday morning, while the upper level
system is beginning to lift out, the sfc trough and 850 mb
temperatures (around-5c) continues to produce le precipitation
(probably rain or rain/snow mix in the highlands) until the mid and
lower level moisture begins to dry out, and the sfc and 850 mb ridge
axis moves through the region. This would seem to limit or stop the
le precipitation, but am unsure about this some of the models are
showing that some precipitation is possible into Friday morning.

Primary forecast concerns...at this point, the winds are the main
concern for Wednesday morning, but as the system moves to the east,
the gradient relaxes and we should see the winds diminish by the
afternoon. On the Great Lakes, it would seem that we should have
fallen to small craft criteria.

After that the main concern is the chance for the le precipitation
to hang on. Some of the markers are there, namely the ridge axis in
the 1000-850 mb flow. Moisture is around 40 to 50% in the 850-700 mb
layer, and the Delta T is around 18 to 19c. So with the moisture on
the edge, and the ridge axis isn't very sharp (it looks somewhat
flat), the Delta T may be the deciding factor. The amount of
precipitation would be light with the lack of moisture. However, the
next concern is do we get some icy conditions on back roads with
the light, wet precipitation and low temperatures around 30f? Sfc
soil temperatures are in the upper 40s. So think that the likelihood
is low, but not zero.

Long term...(thursday night through monday)
issued at 331 am EDT Tue Oct 22 2019

High impact weather potential...minimal.

Extended (friday through monday)...the dry air continues to move
into the region and the high takes over and the precipitation looks
to cease by Friday evening and things remain dry through Sunday
morning. Sunday afternoon, the European model (ecmwf) has a sfc low that moves right
over the forecast area, by Sunday evening. While the GFS has a weak
cold front/shortwave trough move through. If the European model (ecmwf) is right we
will get a decent storm on Sunday. Another shortwave looks to rotate
into the region on Monday night. We'll see. Not particularly
enthused by the European model (ecmwf) idea. However, the models are hinting at
pattern change as the 6-10 day and 8-14 day outlooks have been
showing the last couple of days.

&&

Aviation...(for the 18z tafs through 18z Wednesday afternoon)
issued at 101 PM EDT Tue Oct 22 2019

Stacked low pressure currently centered across Western Lake Superior
will continue to shift northward through the day before accelerating
toward and eventually northeast of Hudson Bay tonight into
Wednesday. Gusty south-southwesterly winds will continue through
much of the taf period, before finally relaxing Wednesday evening.
MVFR ceilings will be common today, especially at pln, mbl and tvc as
occasional showers continue across the region.

&&

Marine...
issued at 331 am EDT Tue Oct 22 2019

Gale force wind gusts will continue to impact the lakes through
tonight before winds/waves begin to subside during the overnight
hours and into Wednesday.



&&

Apx watches/warnings/advisories...
Michigan...Lakeshore flood advisory until 8 am EDT Wednesday for miz020-098.
Lakeshore Flood Warning until 8 am EDT Wednesday for miz025-031.
Lakeshore flood advisory until 5 am EDT Wednesday for miz088-095-
096.
Lakeshore flood advisory until 8 am EDT Wednesday for miz016.
LH...Gale Warning until 5 am EDT Wednesday for lhz348-349.
Small Craft Advisory until 5 am EDT Wednesday for lhz345>347.
Lm...Lakeshore Flood Warning until 8 am EDT Wednesday for lmz346.
Gale Warning until 5 am EDT Wednesday for lmz323-341-342-344>346.
Ls...Gale Warning until 7 PM EDT this evening for lsz321-322.
&&

$$

Update...mg
near term...tl

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