Area Forecast Discussion
Issued by NWS Gaylord, MI

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FXUS63 KAPX 211020
AFDAPX

Area Forecast Discussion
National Weather Service Gaylord MI
620 AM EDT Sun Apr 21 2019

.NEAR TERM...(Today and Tonight)
(Issued at 151 AM EDT Sun Apr 21 2019

High impact weather: Minimal.

Pattern synopsis and forecast:

Early this morning, weak low pressure and a frontal boundary is
crossing upper Michigan/Lake Superior, with warm and shallow moist
mid level advection spreading in across nrn Michigan. This has
resulted in a shallow, yet solid layer of clouds in the mid levels,
spreading mostly cloudy/cloudy skies over most of nrn Michigan.
There was general upper level ridging over the region, but upstream
in the Central Plains and western conus, a shortwave troughing was
ejecting more subtle shortwaves out over the Plains and Upper
Mississippi valley. This was running north of the same frontal zone
that extends back to another low pressure in NE/KS/SD. Forcing
anywhere in the region wasn`t impressive, but there was a LLJ/WAA
and hints of upper divergence along a steep lapse rate gradient
north of the frontal zone. This was producing some showers from ND
into nrn MN.

The frontal zone is expected to drop into areas in and around the
Straits region and stall out through tonight. The aforementioned
forcing and lapse rate gradient work their way eastward through the
day, with some more identifiable shortwave energy/DPVA arriving late
this afternoon and tonight, along and north of this front. This will
result in increasing chances of seeing showers for far nrn lower and
eastern upper, mainly tonight. Further south, the air mass will be
drier with less forcing, and no showers are expected. Fcst soundings
suggest that the layer of clouds in the mid levels thickens a bit
through the day and night, but there does appear to be periods where
it thins enough for the sun to come out at times south of the
frontal zone. Temperatures will be warmest there, with readings in
the 60s, and maybe a few lower 70s. Far nrn lower/far NE lower and
eastern upper will be in the better cloud shield, and also with an
expected lake breeze coming off cold Lake Huron, will result in
highs in the mid and upper 50s. It may turn out colder at the NE
lower coast. Lows tonight will be in the 40s.

&&

.SHORT TERM...(Monday through Tuesday)
Issued at 151 AM EDT Sun Apr 21 2019

High Impact Weather Potential...minimal.

Pattern Synopsis/Forecast...The warm front remains stalled over
Upper Michigan. The models are in agreement that E Upper should
remain in the lighter amounts, with C and W Upper getting the
heavier amounts. Will discuss this more in the concerns section. The
sfc low continues to move NE into N Lower and rain begins to spread
across Lower Michigan during the evening and overnight. Tuesday
morning, the rain will come to an end through the morning, as the
cold front sweeps through. Winds looks like they increase and get
gusty on the back side of the sfc low, and with the 500 mb jet
streak moving in with the dry air. Although, by the evening, the
gradient relaxes and the winds diminish as the sfc high moves into
the Upper Great Lakes.

Primary Forecast Concerns...It looks like the models are "wiggling"
the warm front and jet streak a bit, which allows for the
possibility of rain or heavy rain in E Upper during the day.
However, with the GFS/ECMWF/SREF pretty much on the same page, it
looks like the likelihood is small, and the heavier rain remains
west, and that the rain won`t enter N Lower until late evening. By
that time, the main shortwave looks to have moves NE of ANJ and the
chances of heavy rain is lower. Rain may be possible on Monday,
although the deterministic GFS and ECMWF are a little lower on the
possibility than the SREF and the GEFS.

.LONG TERM...(Tuesday night through Saturday)
Issued at 151 AM EDT Sun Apr 21 2019

High Impact Weather Potential...minimal.

Extended (Wednesday through Saturday)...The western 500 mb trough
digs into the Desert SW while the eastern low has departed the
CONUS. This allows the jet stream to sink south a bit, and allow for
some drier air to settle into the Upper Great Lakes through Thursday
morning. Thursday, the scattered showers are back as a 500 mb jet
streak noses into the Upper Great Lakes. By Friday, things dry out.
Saturday, another 500 mb shortwave begins to move into the Upper
Great Lakes as it moves out of the 500 mb ridge in the Rockies.
Which flattens the ridge out by Sunday morning and potentially back
to the pattern we have today.

&&

.AVIATION...(For the 12Z TAFS through 12Z Monday morning)
Issued at 603 AM EDT Sun Apr 21 2019

Weak low pressure is crossing upper Michigan, with warm and shallow
moist mid level advection continuing to spread a blanket of mid
level clouds over nrn Michigan. This low pressure will lay out a
frontal boundary over nrn Michigan today, and latest data suggests
that the OVC skies will last for several more hours, before some
breaks in the clouds will occur. Am expecting at least BKN mid
level clouds through the night as well, along with light winds.
There is only an outside chance of a sprinkle falling later today .
It`s all VFR however.

&&

.MARINE...
Issued at 151 AM EDT Sun Apr 21 2019

Weak low pressure and a frontal boundary will drop into the region
and stall out through Monday, before a stronger area of low pressure
Monday night. Attm, winds are expected to remain below advisory
criteria through the period, due to pretty strong overlake
stability, despite winds kicking up at times just above the surface.
There will be chances for showers across mainly Whitefish Bay and
the St. Mary`s starting tonight, with chances arriving in all
nearshore waters Monday night, and with a shot at thunderstorms.


&&

.APX WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LH...NONE.
LM...NONE.
LS...NONE.
&&

$$

NEAR TERM...SMD
SHORT TERM...JL
LONG TERM...JL
AVIATION...SMD
MARINE...SMD



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