Area Forecast Discussion
Issued by NWS Gaylord, MI

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FXUS63 KAPX 152300

Area Forecast Discussion
National Weather Service Gaylord MI
700 PM EDT Thu Mar 15 2018

.NEAR TERM...(Tonight through Friday)
Issued at 306 PM EDT Thu Mar 15 2018

...Snow showers winding down...

High Impact Weather Potential...Minimal. Lake snow showers
tonight...sunshine returns on Friday.

Pattern Synopsis/Forecast...Afternoon composite analysis reveals
deep troughing from the the Great Lakes into New England...downstream
from sharp ridging across the central CONUS. Surface low pressure
is over New England with yesterday`s cold front down through the
Ohio Valley...and Canadian high pressure just into NW Ontario. NNW
flow cold advection has been ongoing through the day with
temperatures remaining flat or even falling slightly through the

With colder air spreading into the region...lake effect/lake
enhanced snow showers have been ongoing through the day. Had a nice
flare-up of snow showers late morning into the afternoon that was
a little disconcerting...possibly tied to arrival of a secondary
cold front/push of colder air and weak-ish short wave forcing.
Regardless...had to beef up PoPs over a large part of the CWA and
add some light accumulations. Snow shower intensity has largely
diminished since although snow shower coverage remains widespread
due to the daytime heating component.

Support for lake effect diminishes over the 12 hours or so as
cyclonic flow eases/high pressure and drier air nose down from
Ontario. So...I still plan on having slowly diminishing PoPs
through tonight with some light accumulations in the typical NNW
flow lake effect areas. Sunshine should return on Friday as high
pressure/dry air take control. Still could be some lake cloudiness
around in the morning that should mix out through the day. Expect
highs tomorrow only in the middle 20s to lower 30s which is 5 to
10 degrees below normal for mid March.


.SHORT TERM...(Friday night through Sunday)
Issued at 306 PM EDT Thu Mar 15 2018

...Looking Dry through Sunday...

High Impact Weather Potential...None.

Pattern Synopsis/Forecast...High pressure continues to build into
the region Friday night, with the dry air in the mid and upper
levels (850mb and 700-500 mb layer) over the Upper Great Lakes. With
the main 500 mb flow just north and east of the region, and the 500
mb ridge to the west, we sit in a fast NNW jet flow that keeps the
weather quiet through Sunday.

Primary Forecast concerns...As mentioned with the fast flow and the
position of the jet, there are some shortwave trough at 500 mb that
move through the region with the dry air. One in particular moves
through Saturday night into Sunday morning spinning up a weak
clipper low. The GFS/ECMWF/NAM/SREF solutions have nothing in the
forecast area, but just northeast of Lake Superior and part of
Ontario, the models do produce some snow showers. So will have to
keep an eye on this, if the models have underdone the strength of
the wave and the sfc low, or misplaced the baroclinic zone
associated with the low, and we get into the WAA snow that the
models depict, just outside our area.

.LONG TERM...(Sunday night through Thursday)
Issued at 306 PM EDT Thu Mar 15 2018

Not a whole lot of change from yesterday`s thinking. Right now,
things look to remain mostly quiet through the extended. Continuing
to watch a storm system expected to develop early in the week and
pass through the Ohio Valley. While guidance continues to keep the
main system progged well to our south, signals are starting to show
development of a secondary low, on the northern fringe of the Ohio
Valley low, as a northern stream wave digs through the region. This
is generating some QPF in portions of the CWA, though just how much
of the CWA varies greatly. European guidance is quite a bit further
north with this secondary development, and wanting to bring precip
to a greater portion of the CWA. I`m a bit leary of this, as the
Euro can sometimes be a little slow with these waves in the
extended, and some of the strength of this secondary low looks to be
due to interaction with the surface low in the Ohio Valley. If that
low pushes through faster, the interaction with the northern wave
would be reduced, and displaced further south. This is the general
idea North American guidance is picking up on right now. At this
juncture, I favor the North American guidance, and think the Euro
will speed up with the initial storm system, and the secondary
development will also remain to our south. The consensus blend has
introduced some low chance PoPs for mid-week, which seems reasonable
for now given the uncertainties mentioned.


.AVIATION...(For the 00Z TAFS through 00Z Friday evening)
Issued at 700 PM EDT Thu Mar 15 2018

Lingering light lake effect snow showers will steadily diminish in
areal coverage and intensity tonight...and should come to an end
by Friday morning as high pressure and dry low level air build
into the region. Conditions will occasionally drop to MVFR/IFR
within some snow showers this evening. Gusty NW winds of 15 to 25
kts will diminish to 10 to 15 kts on Friday.




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