National Weather Service - Area Forecast Discussion

000
FXUS63 KAPX 140351
AFDAPX

Area Forecast Discussion
National Weather Service Gaylord MI
1151 PM EDT Sun Oct 13 2019

.UPDATE...
Issued at 940 PM EDT Sun Oct 13 2019

Dominant lake effect band poking into far northern lower MI, aided
by a 500mb trof axis sliding over northern Lake MI. Precip
coverage has been very slowly decreasing away from this band,
thanks to loss of diurnal `heating`. Precip is still mostly
liquid, but more intense returns away from the immediate Great
Lakes coastline are mixy.

1000-850mb winds will veer to the west by midnight as the upper
trof passes, and eventually go wnw by daybreak. This will
cause better banding to be displaced southward with time. Ongoing
activity should be something of a peak as far as precip intensity,
as post-wave subsidence and drying will go to work on ongoing
activity. This will have a larger impact after 2-3am. Have
extended higher pops a little longer into the night.

Meanwhile, those veering winds will bring Superior banding into nw
Chippewa Co. The immediate lakeshore up by Whitefish Pt should be
mixy enough for limited accums, but am a little concerned that
light accums will occur between Paradise and Eckerman. Will allow
for a slushy inch or so there.

In far northern lower, the going half-inch or so possible in some
hillier interior locales looks reasonable.

&&

.NEAR TERM...(Through Tonight)
Issued at 341 PM EDT Sun Oct 13 2019

...Lake induced rain showers along with a little snow...

High Impact Weather Potential: Lakeshore flooding concerns and
potential for isolated waterspouts.

Pattern Synopsis/Forecast: Afternoon analysis reveals deep
occluded low just north of Lake Superior. Associated cold front
appears to be just east of northern Lower Michigan at this
juncture with the heart of the coldest air (neg 6 to neg 7C H8
air over Wisconsin this morning) spreading into the region.
Corridor of f-gen induced precip along the SE edge of the upper
low stretches from central Lower Michigan up through central Lake
Huron but has been weakening over the last several hours.
Widespread lake induced showers continue over northern Lake
Michigan into the U.P. and a good chunk of northern Lower
Michigan, augmented by "heating of the day."

Showers are mainly of the liquid variety at this point, although
some snow/graupel continues to fall in the heavier showers
particularly through the higher terrain areas.

Primary Forecast Concerns: Precip type remains the biggest
challenge along with possible light snow accumulations.

Tonight: Deep stacked low will very slowly rotate eastward across
south-central/southeast Ontario through tonight and right into
Monday, while coldest air overspreads the region. With gradually
weakening synoptic scale forcing, ongoing band of f-gen induced
precip over the SE part of the forecast area falls apart through
early evening. But lake induced showers will continue through tonight
into Monday while low level mean flow veers from southwest to
west. And with loss of heating, bulk of shower activity will
likely become more concentrated up through the more typical SW-W
flow lake effect areas (i.e. parts of eastern upper Mi as well as NW
Lower Mi north of M-72). Also, with loss of heating and the
incoming coldest air, snow will become the more prominent precip
type particularly through the inland higher terrain areas. Some
light snow accumulations (~half an inch) seems warranted through
those areas.

Lakeshore flooding: Winds today have not been as impressive as I
thought they might, although some lakeshore areas are reporting
occasional gusts of 20 to 30 mph. Will leave the lakeshore flood
advisory as-is...set to expire at 11 pm as winds diminish tonight.

&&

.SHORT TERM...(Monday through Wednesday)
Issued at 341 PM EDT Sun Oct 13 2019

High impact weather potential: Minimal.

Pattern synopsis and forecast:

A deep upper level low over Lake Superior will continue it`s trek,
very slowly, towards the northeast. With delta ts of ~20C, mostly
cloudy skies and light rain/snow showers will continue through
Monday night for portions of northwest lower and eastern upper. As
this upper level low continues it`s northeastward trek towards James
Bay, rain will diminish south to north through Monday night as drier
air fills in behind the departing low. Tuesday will see some
precipitation free weather throughout the first half of the day
until chances increase later in the day ahead of a developing
surface low pressure system over the western Great Lakes. WAA precip
will begin during the afternoon hours Tuesday ahead of the
approaching cold front associated with the aforementioned low
pressure system to the west. As the center of this low treks
eastward through northern Michigan Tuesday night, thunderstorms will
be possible. As this system departs to the east, wrap around
moisture with northwest winds will usher in cooler 850mb
temperatures and more precipitation chances. With delta ts of around
16-18C there will be lake effect/enhanced precipitation over
portions of northwest lower, eastern upper, and along the coast of
Presque Isle County through Wednesday. Daytime temperatures will be
in the mid 40s to low 50s, while lows will drop into the low 30s
Monday morning and warmer Tuesday morning...only dropping into the
upper 30s to low 40s (with warmer temperatures near the Great Lakes
coastlines).

.LONG TERM...(Wednesday night through Sunday)
Issued at 341 PM EDT Sun Oct 13 2019

High Impact Weather Potential: Minimal

A progressive pattern persists across the CONUS as combinations of
long wave troughs and upper level disturbances trek through the
Great Lakes region throughout the period. This will bring at least
rain chances to the forecast area, and possibly some light snow
during nighttime hours at times. Will not definitely be
precipitating all the time, but will be moist, and mostly cloudy
conditions throughout the period. Highs will remain to be below
normal...only in the mid 40s to low 50s and begin to warm a bit
Friday...reaching into the mid 50s and then to near 60 by Sunday.

&&

.AVIATION...(For the 06Z TAFS through 06Z Monday night)
Issued at 1151 PM EDT Sun Oct 13 2019

Conditions generally improving.

Slowly weakening low pressure is well north of Superior. Cold air
in the region has contributed lake effect rain/snow showers and
associated low clouds. Coverage of lake effect precip and clouds
will diminish with time, as the coldest air moves downstream and
somewhat drier air works in. Lake effect rain/snow showers will
linger longest at PLN, into Monday morning. A mix of MVFR to VFR
cigs will become all VFR on Monday.

Current sw winds will veer west, and will remain gusty at times.

&&

.MARINE...
Issued at 341 PM EDT Sun Oct 13 2019

Gustier SW winds will slowly diminish some tonight while veering
westerly on Monday. But small craft advisory winds and/or waves
are likely through Monday morning. Waterspouts are also a good
possibility tonight particularly on northern Lake Michigan, the
straits and northern Lake Huron.


&&

.APX WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LH...SMALL CRAFT ADVISORY until 11 AM EDT Monday for LHZ345>349.
LM...SMALL CRAFT ADVISORY until 11 AM EDT Monday for LMZ323-341-342-
     344>346.
LS...SMALL CRAFT ADVISORY until 11 AM EDT Monday for LSZ321.
&&

$$

UPDATE...JZ
NEAR TERM...BA
SHORT TERM...TL
LONG TERM...TL
AVIATION...JZ
MARINE...BA

NWS APX Office Area Forecast Discussion