Area Forecast Discussion
Issued by NWS Gaylord, MI

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000
FXUS63 KAPX 260348
AFDAPX

Area Forecast Discussion
National Weather Service Gaylord MI
1148 PM EDT Sun Sep 25 2016

.UPDATE...
Issued at 938 PM EDT Sun Sep 25 2016

Band of showers making inroads into northern MI. Not a lot of
associated thunder, but there has been an occasional strike or
two, most recently near Ludington. Precip is happening along and
just ahead of a surface cold front (now advancing into western
Lake MI), supported by strong 500mb height falls and 200-300j/kg
of mucape.

Precip band was initially quite narrow. However, near- and post-
frontal showers have become prevalent over eastern WI in the past
1-2 hours. This is in line with the going forecast, which
maintains fairly high pops for much of the night, with diminishing
trend occurring w to e after 06z/2am.

Some fine-tuning adjustments made to precip onset, but otherwise
forecast changes to this point are minor.

&&

.SHORT TERM...(This evening and overnight)
Issued at 348 PM EDT Sun Sep 25 2016

High impact weather potential: A few thunderstorms possible
tonight. No severe weather. Waterspout potential increasing Monday.

Pattern synopsis and forecast:

Upper level ridging is exiting east, making way for a negatively
tilted upper trough and associated low pressure in Ontario. A couple
of bands of showers and a few storms continues to slowly make their
way toward nrn Michigan from Wisconsin, the first band heading into
Green Bay. These showers/storms are within a corridor of deeper
moisture, ahead of a cold front stretched out across the upper
Mississippi valley. Forcing was on the increase, due mainly to upper
divergence and strong dpva. Behind this frontal precipitation, an
area of deeper moisture was wrapped in low level cyclonic flow and
an 850mb air mass with temperatures of 6-8C.

The deeper moisture/cold front continues to make progress into nrn
Michigan tonight, dragging the showers and possible few storms
across the entire area. Most folks will see some rain, as showers
are expected to fill in more with time as forcing is expected to
increase further. The frontal showers are likely to be exiting the
eastern CWA shortly after daybreak, and a lull in the action is
anticipated as the air mass dries out. Temperatures will already be
cold enough for the lakes to be activated, but the drier air mass
will likely just result in isolated/scattered light rain showers. It
will not be until later Monday afternoon when the deeper wrap around
moisture arrives that more numerous showers will develop. May be
looking at a chance for waterspouts then, but low level winds are
kinda strong and there is no foreseeable sfc trough axis that is
a more favorable setup.

Low temperatures tonight in the mid to upper 50s, with highs
tomorrow in the coldest air mass of the season only in the upper
50s to lower 60s. Gusty conditions and the showers will make it feel
rather raw outside.

.LONG TERM...(Monday through Sunday)
Issued at 348 PM EDT Sun Sep 25 2016

...Cool and breezy into midweek with numerous showers...

High Impact Weather Potential: Marine headlines the main issue with
widespread Small Craft conditions through Tuesday evening. Isolated
waterspouts possible as well.  Numerous showers/some thunder
possible through Tuesday evening along with some frozen (ice
pellets) precipitation in heavier showers.

Pattern Synopsis/Forecast: Splitting full-latitude short wave trough
crossing the plains and heading into the midwest this afternoon will
close off and spin over the Great Lakes through midweek.  System
will dig into the Ohio/Tennessee valleys Thursday.  Deep layer
cyclonic flow will bring unsettled weather to Michigan Tuesday into
Wednesday...though as upper level support begins to shift south with
time surface pattern will weaken.

Primary Forecast Concerns: Instability showers off Lakes Superior
and Michigan should be fairly ubiquitous Monday night and Tuesday
with low single digit 850mb temperatures overlying water
temperatures of 17-18C on Lake Superior and around 21C on Lake
Michigan.  Deep layer moisture wrapping around the parent
circulation centered over the Lake Superior vicinity will aid in
precipitation coverage...as will a diurnal heating component during
the day Tuesday.  Instability/cloud depths will likely be enough to
support a few lightning strikes...and possibly some graupel/ice
pellet showers as well.

Things will begin to shift south Tuesday night...as the deep
circulation begins to unwind a bit and the center of it will drop
into the Lower Peninsula.  Winds becoming more easterly on the north
side of the circulation will end lake effect showers for eastern
Upper.  Showers will probably linger across much of northern Lower
Wednesday...but a better chance for a drying trend across eastern
Upper.

Gusty winds will continue Monday night/Tuesday especially along the
northwest Lower Michigan shoreline and around Whitefish Point with
wind gusts in excess of 30mph.  High temperatures Tuesday will be
mainly in the 50s...maybe a bit warmer Wednesday especially where
some sun can break out during the afternoon.

JPB

Sunny and seasonably warm temperatures will highlight the extended
period as high pressure settles overhead. Consensus blends have
added slight rain chances across northern lower for Saturday, as
some guidance is showing a slight retrograde of the cutoff low that
brought early week rain showers. This gives it a bit of a northward
path before fully lifting off, bringing it`s influence once again
into northern Michigan. Certainly not high confidence in that
solution, but will leave it in for now. Temperature trends continue
to look above normal through the extended.

ALM

&&

.AVIATION...(For the 06Z TAFS through 06Z Monday night)
Issued at 1143 PM EDT Sun Sep 25 2016

Cigs decreasing to MVFR to IFR levels overnight into Monday
morning.

Cold front will advance east from eastern WI tonight. Showers/few
TSRA will occur, diminishing from w to e very late. After a
relative lull Monday morning, rain coverage will increase again
in nw lower MI in the afternoon as cooler air moves in and lake
effect develops. Cigs will lower overnight, with MVFR to IFR
conditions developing. Improvement to marginal MVFR/VFR conditions
by afternoon.

Se to s surface winds tonight, a bit gusty at times. LLWS ending
overnight. Winds will veer sw to w and become rather gusty on
Monday.

&&

.MARINE...
Issued at 348 PM EDT Sun Sep 25 2016

S/SE winds ramp up tonight ahead of an advancing cold front and
showers, especially across Whitefish Point where some low end gales
are expected. The cold front crosses by daybreak with cold advection
resulting in lake effect rain showers and renewed gusty conditions
out of the SW through Tuesday. All areas will be in advisory level
winds Monday, and also into Tuesday for many nearshore waters.
Chances for waterspouts develop Monday, but the better chance will
be Monday night into Tuesday with the passage of a sfc trough.


&&

.APX WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LH...SMALL CRAFT ADVISORY until 6 PM EDT Tuesday for LHZ345>349.

LM...SMALL CRAFT ADVISORY until 6 PM EDT Tuesday for LMZ323-341-342-
     344>346.

LS...SMALL CRAFT ADVISORY until 6 PM EDT Tuesday for LSZ322.

     GALE WARNING until 5 AM EDT Monday for LSZ321.

&&

$$

UPDATE...JZ
SHORT TERM...Dickson
LONG TERM...JPB/Mayhew
AVIATION...JZ
MARINE...Dickson



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