Area Forecast Discussion
Issued by NWS Gaylord, MI

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FXUS63 KAPX 210005

Area Forecast Discussion
National Weather Service Gaylord MI
805 PM EDT Thu Oct 20 2016

.SHORT TERM...(This evening and overnight)
Issued at 339 PM EDT Thu Oct 20 2016

...Lake induced clouds/showers tonight and Friday...

High Impact Weather Potential: Minimal outside of a few
waterspouts on Lake Michigan overnight into Friday.

Pattern Synopsis/Forecast: 18z surface analysis shows the upper
Great Lakes stuck in between high pressure spanning the central/
northern Plains...and incipient cyclogenesis over Kentucky/West
Virginia.  Northerly flow between these systems continues to funnel
cooler air into and across the warmer lakes...resulting in a
stratocumulus field across the Upper Peninsula...and layered cloud
decks across northern Lower Michigan with shallow stratocumulus
beneath a mid/high cloud deck along anticyclonic shear side of an
140kt jet axis cutting southwest-northeast across the forecast area.
Elongated rain band associated with developing Ohio Valley low
center and attendant frontal zone has remained south of the forecast
area today...while scattered lake induced showers have been drifting
in off Lake Superior and into central/eastern Upper Michigan.

Primary Forecast Concerns: Lake clouds/showers are expected to
persist...with flow becoming primarily from the north tonight best
focus for showers will likely be along/west of US-131 across
northwest Lower.  May also see some showers right along the US-23
corridor in northeast Lower...while current shower activity clipping
western portions of Mackinac county will probably turn away from the
eastern end of the U.P. overnight.  May see some thinning of the
cloud cover across far eastern Upper (along the St. Mary`s
river/Drummond Island) and interior northern Lower as high level
moisture pulls out.

.LONG TERM...(Friday night through Thursday)
Issued at 339 PM EDT Thu Oct 20 2016

Friday night through Sunday...

...A rather uneventful weather weekend expected...

High impact weather potential: None

Pattern synopsis and forecast:

Current rather progressive, somewhat zonal flavor to the larger
scale NOAM pattern set to slow down and become a bit more amplified
heading through this weekend...owning in large part to strong low
pressure set to develop over the northeast states into the Canadian
Maritimes. Although most active weather will remain well off to our
east tied to this system, backside caa will result in a seasonably
chilly start to the weekend. Airmass modification will be a quick
one (like it has been this fall), returning temperatures to near
seasonal levels by Sunday. Low amplitude and fast moving wave may
bring a late Sunday shower threat in what should otherwise should be
a mostly dry weekend.

Primary forecast concerns:

Cloud and temperature trends through Sunday. Addressing Friday
evening lingering light lake shower potential as well those later
Sunday shower concerns.


Only real issue Friday night through Saturday night is one of cloud
trends, although may still be dealing with some pesky very light lake
induced rain showers in favored north flow areas early Friday
evening. That cloud forecast, especially Friday night into Saturday,
remains one rather formidable challenge. Still plenty of enough cold
air in slowly veering lower level wind field to induce lake driven
strato-cu development right into the start of Saturday. Will trend
somewhat pessimistically in favored lake areas, waiting until later
Saturday morning to really begin to thin clouds out. Narrow surface
ridge axis pivots overhead later Saturday into Saturday night,
continuing the dry weather theme under partly cloudy skies. That
idea continues into at least the start of Sunday. Low amplitude and
fast moving wave mentioned earlier looks to arrive sometime later
Sunday. Still some lingering uncertainty on its exact timing, but
general consensus for its influence to be felt by later Sunday
afternoon across at least the northwest half of the area. Not much
forcing or moisture to be had, but definitely enough there to
warrant at least some shower mention.

For a change, high temperatures will remain a touch below normal
Saturday, when some areas will likely not get out of the upper 40s.
That comes to an end Sunday, when widespread highs back into the 50s


Extended (Sunday night through Thursday) issued at 300 PM EST THU
Oct 20 2016

The 500mb pattern shows a transient ridge in the central
conus...then flattening out to a "messy zonal" flow from mid week
on. A couple shortwave trough move through the flow to provide
period shots at precipitation. Outside of some possible brief lake
contributions on Monday...the first half of the extended looks
generally dry, with a more substantial front lifting over the lakes
late Wednesday through Thursday to be the next chance for
appreciable rainfall. Temperatures will be running real close to
seasonal norms...with overnight lows on the warm side of normal.



.AVIATION...(For the 00Z TAFS through 00Z Friday evening)
Issued at 744 PM EDT Thu Oct 20 2016

Air temperatures have gotten cold enough to activate the lakes.
Lake effect sprinkles/light rains have developed in northerly flow
regimes and will impact mainly TVC/APN/MBL. Skies will be BKN-
OVC over this time and prevailing low end VFR. Winds will be
generally 10kts or less with gusts under 20 knots tomorrow


Issued at 339 PM EDT Thu Oct 20 2016

Low end small craft advisory conditions along the Lake Huron
nearshore south of Thunder Bay tonight and through the day Friday.
Winds may also be gusty in these same nearshore zones on Saturday.
Isolated waterspouts possible after midnight tonight and through the
day on Friday along northwest Lower Lake Michigan nearshore zones.


LH...SMALL CRAFT ADVISORY until 5 PM EDT Friday for LHZ348-349.



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