Area Forecast Discussion
Issued by NWS Gaylord, MI

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718
FXUS63 KAPX 220801
AFDAPX

Area Forecast Discussion
National Weather Service Gaylord MI
401 AM EDT Wed Mar 22 2017

.NEAR TERM...(Today and tonight)
Issued at 359 AM EDT Wed Mar 22 2017

High impact weather potential: None.

Pattern synopsis and forecast:

Upper level troughing and yesterday`s powerful cold front have
shifted well east of nrn Michigan, while strong sfc high pressure
continues to track SE from far western Ontario. 850mb temperatures
of -14C to -16C in still brisk (but weakening) and veering northerly
flow were creating lake effect clouds and scattered flurries. Most
of this activity was in NW lower, especially the higher terrain. In
some of the lower elevations, doubt these flurries seen on radar are
even making it to the ground, as the low level air mass continues to
significantly dry. The entire atmosphere was dry, proven on latest
satellite imagery showing clear skies all around the Great Lakes,
outside of the lake effect.

The core of deep dry air will remain over nrn Michigan today and
tonight, while the strong sfc high pressure settles in this evening,
then pushes SE through the night. Lake effect clouds will persist
into just past daybreak, while any remnant flurries are likely to
fade sooner as the strong subsidence/lowering inversion from the
advancing high pressure squashes through the shallow overlake mixed
layer. This will result in very sunny skies for all areas later this
morning or by early afternoon. The pressure gradient continues to
loosen up by daybreak too, and gusty conditions will vanish. By
evening when the high is over nrn Michigan, calm winds develop and
decoupling will be fast with rapid cooling. With highs in the upper
20s to lower half of the 30s, and only some invading high level
clouds later tonight, can see a big diurnal swing, especially the
low lying areas despite weak WAA just above the sfc overnight. This
is especially true for the low lying/typically colder locales where
reading can dip into the single digits. Elsewhere, low teens
expected. Already lowered to these numbers from guidance which is
likely not cold enough.

&&

.SHORT TERM...(Thursday through Friday night)
Issued at 359 AM EDT Wed Mar 22 2017

...Quiet weather Thursday mixed precipitation Thursday night...

High Impact Weather Potential...The sfc min RH will be at or below
25% on Thursday. While temperatures and winds won`t be out of
criteria, there could be some minor impacts for fire weather
purposes.

There is still an icing potential Thursday night in the interior
portion of N Lower and in E Upper, but it is vary uncertain.

Pattern Synopsis/Forecast...Thursday, High pressure slowly moves out
of  the Upper Great Lakes and produces dry weather. Thursday night,
the precipitation is expected to move into the region. The models
are in good agreement about the formation of precipitation on the
warm front, the thermal fields for Thursday night into Friday morning
still remain a bit uncertain. Looking at the model soundings, the
boundary layer temperatures are right around freezing, and while
there may be a brief dip in the sfc temperatures with the onset of
the precipitation with the strong WAA going on, it seems that the
temperatures should pop back up from the WAA. So will expect a
wintry mix of precipitation, with some light icing as we go into
Friday morning. Friday the temperatures warm and we get all rain as
the warm front continues to produce rain. Friday night again a
wintry mix is possible as the cooler drier air begins to push south.

Primary Forecast Concerns...The thermal profile will be the main
concern, as this could go either way, but feeling from a
meteorological stand point, with the southerly wind, that this ends
up being mainly a rain event with short period of ice at the onset
of precipitation.

&&

.LONG TERM...(Saturday through Tuesday)
Issued at 359 AM EDT Wed Mar 22 2017

High Impact Weather Potential...Icing potential Friday through
Sunday in the interior portion of N Lower and in E Upper.

Extended (Saturday through Tuesday)...Saturday, the warm air moves
north again and the mixes change to rain again. The GFS and ECMWF do
have some icing in the model soundings again Saturday night into
Sunday. So will have some FZRA in the forecast, or a the vary least
will mention it here and in the HWOAPX and related graphics. Sunday,
the rain moves through the region with the 500 mb low that moves
through downstate. Monday, both model have low chance precipitation
with the system in the Mid-Mississippi Valley. Tuesday, the models
have two solutions, the GFS with a 500 mb low that swing over
Michigan and bring rain or rain/snow to the region and the ECMWF
with a 500 mb ridge and dry air. will have some low chance pops in
for Tuesday and clear things out Tuesday night.

&&

.AVIATION...(For the 06Z TAFS through 06Z Wednesday night)
Issued at 1106 PM EDT Tue Mar 21 2017

Large area of Canadian high pressure is centered over southern
Manitoba producing cold northerly flow across the Great Lakes.
Narrow corridor of lake cloud cover light snow showers/flurries
stretches from NW lower Michigan back up into eastern Lake
Superior. This batch of lake cloud cover and light snow showers
will shift westward toward the Lake Michigan shoreline overnight
as low level mean winds veer more north/northeasterly. So, light
snow showers and BKN-OVC VFR cloud cover will remain a possibility
at TVC/MBL for the next several hours. Clouds/snow showers may
ultimately push offshore toward Wednesday morning. PLN/APN will
remain solid VFR although SCT-BKN clouds will impact PLN early on.

On Wednesday, high pressure/dry air/strong subsidence build over
the state. This will lead to lots of sunshine/VFR conditions along
with much weaker surface winds.


&&

.MARINE...
Issued at 359 AM EDT Wed Mar 22 2017

Current gusty northerly winds will weaken through daybreak, with
light winds expected this evening while strong sfc high pressure
will be overhead. This high slides east overnight into Thursday with
light southerly flow developing. These southerly winds will increase
Thursday night, but mainly just above the water sfc due to
increasing stability. While data does not suggest any critical
thresholds being met, gotta believe that advisory level winds will
at least be possible, especially the NW lower nearshore waters with
added coastal convergence.

&&

.APX WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LH...SMALL CRAFT ADVISORY until 6 AM EDT early this morning for
     LHZ345>349.
LM...SMALL CRAFT ADVISORY until 6 AM EDT early this morning for
     LMZ323-341-342-344>346.
LS...SMALL CRAFT ADVISORY until 6 AM EDT early this morning for
     LSZ321-322.
&&

$$

NEAR TERM...SMD
SHORT TERM...JSL
LONG TERM...JSL
AVIATION...TBA
MARINE...SMD



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