Small Craft Advisory 77, NWS Gaylord, MI

347 
WHUS73 KAPX 180334
MWWAPX

URGENT - MARINE WEATHER MESSAGE
NATIONAL WEATHER SERVICE GAYLORD MI
1134 PM EDT SUN SEP 17 2017

LSZ321-180900-
/O.CON.KAPX.SC.Y.0077.000000T0000Z-170918T0900Z/
WHITEFISH BAY (U.S. PORTION)/WHITEFISH POINT TO POINT IROQUOIS MI-
1134 PM EDT SUN SEP 17 2017

...SMALL CRAFT ADVISORY REMAINS IN EFFECT UNTIL 5 AM EDT MONDAY...

A SMALL CRAFT ADVISORY REMAINS IN EFFECT UNTIL 5 AM EDT MONDAY. 

* PLEASE SEE THE LATEST MARINE FORECASTS FOR MORE DETAILED 
  INFORMATION. 

PRECAUTIONARY/PREPAREDNESS ACTIONS 

INEXPERIENCED MARINERS...ESPECIALLY THOSE OPERATING SMALLER
VESSELS SHOULD AVOID NAVIGATING IN THESE CONDITIONS.

$$

670 
WHUS73 KAPX 180757
MWWAPX

URGENT - MARINE WEATHER MESSAGE
NATIONAL WEATHER SERVICE GAYLORD MI
357 AM EDT MON SEP 18 2017

LSZ321-180900-
/O.CAN.KAPX.SC.Y.0077.000000T0000Z-170918T0900Z/
WHITEFISH BAY (U.S. PORTION)/WHITEFISH POINT TO POINT IROQUOIS MI-
357 AM EDT MON SEP 18 2017

...SMALL CRAFT ADVISORY IS CANCELLED...

THE NATIONAL WEATHER SERVICE IN GAYLORD HAS CANCELLED THE SMALL
CRAFT ADVISORY. 

$$

Area Forecast Discussion
National Weather Service Gaylord MI
314 PM EDT Sun Sep 17 2017

.NEAR TERM...(Tonight through Monday)
Issued at 257 PM EDT Sun Sep 17 2017

...Showers end this evening...

High impact weather potential...A few rumbles of thunder through
early this evening.

Pattern synopsis/forecast...Cold front continues to work its way
east across the area this afternoon. Broken band of showers tied to
this passing front, with just enough instability to kick off a few
non-severe thunderstorms (latest SPC meso-anaylsis shows upwards of
500 or so J/KG of mean layer cape across portions of northern lower
Michigan). Descent clearing taking shape just to our west as weak
high pressure builds through Minnesota and into Western Wisconsin.

Above surface features expected to remain fairly transient through
the near term, with overhead cold front clearing the area fairly
quickly early this evening, allowing that upstream high to build
overhead later tonight and through the day Monday.

Timing the end of the shower threat this evening and
cloud/temperature trends through Monday are the primary forecast
concerns.

Details: Band of showers expected to exit stage right rather quickly
this evening. Still looking at a few rumbles of thunder as lingering
instability is utilized. Not expecting anything severe, but could be
looking at brief gusty winds through precip core loading and
attendant wet microbursts. Rest of the overnight looks dry as high
pressure steadily builds into the area. Core of deepest post-frontal
low level moisture pivots to our north, but may be just enough
moisture to drum up some strato-cu. Temperatures expected to tank
quite nicely where skies remain clear (into the 40s by morning),
likely allowing a bit of fog to develop in those low lying and
sheltered areas.

Although a bit cooler, expected highs in the upper 60s to lower 70s
on Monday are still near or a bit above long term normals. Only a
few cu and late day increasing high clouds are expected in an
otherwise sun-filled day.

&&

.SHORT TERM...(Monday night through Wednesday)
Issued at 257 PM EDT Sun Sep 17 2017

...Small chances of showers at times...

High Impact Weather Potential...Slight chance of thunderstorms for
parts of northern MI Wednesday afternoon.

Pattern Synopsis/Forecast...A weak shortwave will ripple across the
Upper Great Lakes region Monday night into Tuesday. Deepening
cyclonic flow over the Pacific Northwest will then lead to an
amplifying upper ridge over the Great Lakes heading into midweek.
Warm air advection will strengthen over northern Michigan on
Wednesday as southerly return flow increases ahead of an approaching
cold front. Highs Tuesday will reach the low 70s for most, climbing
through the 70s on Wednesday with some spots reaching the low 80s.

Primary Forecast Concerns...Shower chances for Monday night into
Tuesday and again on Wednesday.

Models seem to be trending towards less shower activity across
northern MI Monday night into Tuesday, largely due to limited
moisture and weak forcing associated with the passing shortwave. The
GFS and NAM both have PWATs dropping below 1 inch Tuesday morning,
keeping the better moisture downstate. They also never really have
the atmospheric column reaching full saturation, as evidenced by
forecast soundings keeping somewhat of a dry layer just above the
surface. So this forecast has lowered PoPs a bit for Monday night
into Tuesday, focusing them more south of M-32. Would not be
surprised if later forecasts continue trending towards a drier
solution.

Southerly return flow developing on Wednesday will draw increasing
moisture into northern Michigan. The question becomes whether we see
any showers or storms develop in response to the isentropic lift
that gets going over eastern Upper and northwest Lower. This would
be right on the periphery of the upper ridge, so this many days out
there is low confidence in whether showers will actually materialize
over parts of northern MI. Will keep low end PoPs going for now,
however.

&&

.LONG TERM...(Wednesday night through Sunday)
Issued at 257 PM EDT Sun Sep 17 2017

Well above normal temperatures will be the story through the
extended period as strong ridging builds across the eastern CONUS.
Still looks like we could make a run at record highs in some
locations. The blocky downstream pattern is certainly helping this
ridging build, so an earlier than progged break in the block could
allow the troughing over the western CONUS to move in earlier than
currently expected, and bring temperatures closer to normal. But
current indications are for well above normal temperatures to
persist at least through the weekend.

&&

.AVIATION...(For the 18Z TAFS through 18Z Monday afternoon)
Issued at 125 PM EDT Sun Sep 17 2017

Cold front will cross west to east across the area this afternoon
and early evening. Showers, and perhaps a few thunderstorms, will
develop along this front, with the greatest coverage expected
along and east of Interstate 75. May see brief periods of MVFR
cigs as these showers pass overhead. Band of MVFR cigs expected to
develop in the post-frontal environment for a few hours this
evening, with cigs likely lifting and scattering out through the
overnight. More high clouds expected Monday morning. Southwest
winds expected to become northwest to north after the cold front
passes.

&&

.MARINE...
Issued at 257 PM EDT Sun Sep 17 2017

A cold front passing the area this afternoon and early
evening will quickly veer the winds around to north and northeast.
Winds will be a touch gusty at times tonight, and with the long
fetch, may produce borderline small craft advisory criteria waves on
Whitefish Bay. Northeast to east winds expected to continue into
Monday night. A few showers and thunderstorm are expected into this
evening, particularly across Lake Huron. Brief gusty winds may
accompany any thunderstorms.

&&

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

NEAR TERM...MB
SHORT TERM...MK
LONG TERM...AM
AVIATION...MB
MARINE...MB

Hazardous Weather Outlook
National Weather Service Gaylord MI
305 PM EDT Sun Sep 17 2017

LHZ345>349-LMZ323-341-342-344>346-LSZ321-322-MIZ008-015>036-041-
042-181200-
Straits of Mackinac within 5 nm of Mackinac Bridge including
Mackinac Island-St Ignace to False Detour Channel-
5NM East of Mackinac Bridge to Presque Isle Light MI including
Bois Blanc Island-
Presque Isle Light to Sturgeon Pt MI Including Thunder Bay
National Marine Sanctuary-Sturgeon Pt to Alabaster MI-
Grand Traverse Bay south of a line Grand Traverse Light to
Norwood MI-Seul Choix Point to 5NM West of Mackinac Bridge-
Norwood MI to 5NM West of Mackinac Bridge including Little
Traverse Bay-Sleeping Bear Point to Grand Traverse Light MI-
Point Betsie to Sleeping Bear Point MI-
Manistee to Point Betsie MI-
Whitefish Bay (U.S. Portion)/Whitefish Point to Point Iroquois MI-
St. Marys River Point Iroquois to E. Potagannissing Bay-Chippewa-
Mackinac-Emmet-Cheboygan-Presque Isle-Charlevoix-Leelanau-Antrim-
Otsego-Montmorency-Alpena-Benzie-Grand Traverse-Kalkaska-Crawford-
Oscoda-Alcona-Manistee-Wexford-Missaukee-Roscommon-Ogemaw-Iosco-
Gladwin-Arenac-
305 PM EDT Sun Sep 17 2017

This hazardous weather outlook is for northern Lower Michigan...
eastern Upper Michigan...and adjacent nearshore waters of Lake
Michigan...Lake Huron and Lake Superior.

.DAY ONE...Rest of this afternoon and tonight.

A few thunderstorms are expected through early this evening,
especially across north central and northeast lower Michigan.
Severe storms are not expected, though locally heavy rain is
possible.

.DAYS TWO THROUGH SEVEN...Monday through Saturday.

There is a slight chance of thunderstorms Wednesday afternoon
through Wednesday night.

.SPOTTER INFORMATION STATEMENT...

Spotter activation is not anticipated.

&&

For more information visit http://weather.gov/gaylord.

msb