Area Forecast Discussion
Issued by NWS Gaylord, MI

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FXUS63 KAPX 282013

Area Forecast Discussion
National Weather Service Gaylord MI
413 PM EDT Wed Jun 28 2017

.NEAR TERM...(Tonight through Thursday)
Issued at 413 PM EDT Wed Jun 28 2017

...Showers and some storms tonight...

High Impact Weather Potential...minimal. Marginal risk for severe
storms producing gusty winds tonight.

Pattern Synopsis/Forecast...Afternoon composite analysis reveals a
well defined short wave moving through northern Iowa and attendant
surface low tracking slowly across Minnesota. Warm front arcs
southeastward through Wisconsin and down through the Ohio
Valley...and trailing cold front stretches down through Nebraska.
Strong low level flow ahead of the low continues to draw sharp
Theta-E ridge axis through the Midwest and into the western Great
Lakes. Very leading edge of that gradient is making northeastward
progress through eastern upper and NW lower Michigan...evidenced
by our initial spotty showers. Meanwhile...subtle short wave
trough ahead of the main wave (with a couple embedded leftover
MCV`s) is making steady progress into the state...driving more
widespread showers into the region. Most (if not all) convection
is further back near/under the main short wave in SW Wisconsin
into Iowa...where clearing skies/heating and much better
instability can be found.

Primary Forecast Concerns...Severe weather threat and heavy rain

Categorical rainfall will spread east-northeastward across the CWA
over the next several hours. Thunderstorm threat initially looks
minimal. However...instability axis right in behind the main batch
of rain (where convection is currently expanding) will be nosing
up into the region later this evening and overnight...which will
lead to some thunderstorms as core of 50-60 knot low level jet
punches into the region. Plenty of flow aloft/bulk shear for
organized storms...although bad time of the day for severe. But...
still cannot rule out the marginal risk.

Heavy rain threat: Initial batch of rainfall is not impressive...
mainly under 0.3" in six hours from obs upstream. But line of
developing convection within the instability channel from northern
Iowa into south-central Wisconsin is impressive. If it can
continue to expand and nose into the region we could see some
heftier rainfall amounts later tonight. Current extrapolation
suggests that might be up through northern lower Michigan. But
will just have to see how things unfold.

Thursday...cold/occluded front swings through the region early
on with a dry punch kicking through the region. This will end
precip threat early although some showers may linger in eastern
upper through the day especially as deformation "wrap around" part
of the upper circulation slides through upper Michigan. Have to
also wonder if we see some afternoon showers bubble up across NE
lower Michigan provided we keep enough low level moisture around.


.SHORT TERM...(Thursday night through Saturday)
Issued at 413 PM EDT Wed Jun 28 2017

...Unsettled weather continues...

High impact weather potential...Severe weather possibility Friday

Pattern synopsis/forecast...Upper trough takes shape in the Plains
as energy dives south out of Canada. This slows down progression of
broad cold front. Wave moving up the front helps sfc low develop and
move into MI from the midwest. Once the low and front move
east...Great Lakes region is under the influence of upper trough
through the weekend.

Primary forecast concerns/challenges...Severe weather potential

Thunderstorms developing ahead of the cold front Friday will be
focused near the surface low. Southerly low level flow will bring in
deeper moisture and enhance shear mainly over Southern MI but could
also be as far N as our CWA. SPC day 3 outlook talking about
possibility of tornadoes due to highly shear environment. Latest
model trends are a bit farther S with the low and precipitation.

Cold front passes but upper trough still in place for Saturday.
Trough axis still to the west by afternoon. CAPE values peak around
500 J/kg so not a good severe day but enough instability for daytime
heating to help development of cu and scattered showers/tstorms.


.LONG TERM...(Saturday night through Wednesday)
Issued at 413 PM EDT Wed Jun 28 2017

A rather progressive pattern continues through the beginning of the
extended period...with chances of precipitation and a bit cooler
than normal temperatures. The beginning of the next work week will
see a break from the surface high pressure
builds into the Great Lakes region from Hudson Bay. Temperatures
will also begin moderating Monday with some places reaching into the
mid to upper 70s and then the low 80s by Wednesday. Nighttime
temperatures will drop into the low to mid 50s.


.AVIATION...(For the 18Z TAFS through 18Z Thursday afternoon)
Issued at 309 PM EDT Wed Jun 28 2017

VFR conditions linger across northern Michigan for the moment.
Initial line of showers is making progress through NW lower
Michigan and will cross the region over the next few hours. Brief
showers and some lowering of CIGS (VFR) can be expected. More
widespread rainfall is back across central/eastern Wisconsin along
and ahead of advancing short wave trough that will swing through
the region over the next several hours. More widespread rainfall
will spread into the region late this afternoon into this evening
and eventually bring MVFR cigs to the terminal sites as we go
through the evening...lingering into Thursday morning. Some
thunder is possible through the course of the night.

On Thursday...upstream low pressure system slips through Lake
Superior kicking cold/occluded front through northern Michigan
early on...followed by a dry punch of air sliding through northern
lower Michigan along the southern fringe of the low. This will
kick the batch of rain out of northern lower Michigan during the
morning hours with cigs improving to VFR heading into the
afternoon. Possible we might see some showers bubble up across NE
lower Michigan during the afternoon...if enough low level
moisture lingers.


Issued at 325 AM EDT Wed Jun 28 2017

Today through Thursday night...As an area of low pressure migrates
from the Northern Plains to the Upper Great Lakes tonight, the
gradient is expected to tighten up and produce small craft winds
and waves later this morning and into the night. Winds should
begin to diminish as the low moves north of the UP, and gradient
relaxes again. High pressure settles into the Upper Great Lakes
and the winds remain below small craft thresholds through Thursday


MI...BEACH HAZARDS STATEMENT through Thursday morning for MIZ020-025-
LH...SMALL CRAFT ADVISORY from 8 PM this evening to 8 AM EDT Thursday
     for LHZ346-347.
     SMALL CRAFT ADVISORY until 8 AM EDT Thursday for LHZ348-349.
LM...SMALL CRAFT ADVISORY until 8 AM EDT Thursday for LMZ323-341-342-
LS...SMALL CRAFT ADVISORY from 8 PM this evening to 8 AM EDT Thursday
     for LSZ322.
     SMALL CRAFT ADVISORY until 8 AM EDT Thursday for LSZ321.


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