National Weather Service - Area Forecast Discussion

000
FXUS63 KAPX 241839
AFDAPX

Area Forecast Discussion
National Weather Service Gaylord MI
239 PM EDT Sun Oct 24 2021

.NEAR TERM...(Through Tonight)
Issued at 238 PM EDT Sun Oct 24 2021

High Impact Weather Potential: None.

Pattern Synopsis/Forecast: Upper-level low pressure that`s aided to
bring periods of lake effect showers over the past several days
continues to slowly shift east across northern Ontario this
afternoon...expected to advance into western Quebec by Monday
morning. Attention quickly turns to our southwest as a negatively
tilted upper wave and attendant strengthening surface reflection
trek across the central plains into the mid-MS Valley by this
evening, and to near Chicago by Monday morning. Early effects of
that system will be felt this afternoon as our low-level wind field
is significantly disrupted with flow turning more northerly, and
eventually northeasterly this evening/overnight. Rain chances slowly
increase across far southern sections of the forecast area for the
overnight hours.

Primary Forecast Concerns: Rain potential and increasingly gusty
winds.

Any lingering isolated lake effect rain showers will continue to
diminish and come to an end later this afternoon/evening as the
primary focus revolves around the aforementioned system to our
southwest.

A warm front will advance across the Ohio Valley this afternoon into
tonight, tied to that system currently centered near the KS/NE/MO
border. Isentropic ascent and ample deep moisture should yield
significant precipitation north of the this boundary across IL, IN,
OH, and southern MI. The northern fringe of this precipitation will
try to press northward tonight, perhaps making it as far north as
the far southern reaches of the forecast area. However, increasingly
dry northeast flow out of Canada is expected to impede its northward
progress as it`ll certainly be a battle of moist air to the south
and dry air arriving from the north. As a result, expecting a sharp
cutoff in precipitation with northward extent across our CWA with
latest trends continuing to support a somewhat slower northward
progression. This supports chance PoPs arriving across southeastern
areas this evening and eventually toward the M-55 corridor
overnight. While the primary p-type will remain rain with up a tenth
of a inch of QPF or so by Monday morning, suppose a few flakes
mixing in initially isn`t out of the question, mainly west of I-75.

Otherwise, aforementioned increasing northeast winds will make it
feel even chillier than the progged lows tonight...ranging from as
cold as the mid 20s in eastern upper and through the 30s across
northern lower (warmest near Saginaw Bay and along the immediate
Great Lakes lakeshores).
&&

.SHORT TERM...(Monday through Wednesday)
Issued at 238 PM EDT Sun Oct 24 2021

...Showers for Northern Lower Monday...

High Impact Weather Potential...Minimal.

Pattern/Synopsis...Early in the new work week brings a shortwave
treking into the Ohio Valley, which phases a bit with residual
energy sinking through southern Ontario. This results in elongated
shortwave troughing through the lower Great Lakes through Tuesday.
After this shortwave ridging pushes over the upper Great Lakes for
midweek. Meanwhile longwave troughing shifts from the west coast
early in the week to the Plains by Wednesday...poised to bring us
our next round of precip late week.

Forecast/Details...On Monday a 1003mb surface low moves through the
Ohio Valley with a 1030mb high parked over nrn Ontario. This puts us
under a tight gradient with gusty northeast winds through Monday.
Great moisture will be riding up and over a warm front over srn
Michigan. PWAT`s get up to over an inch downstate with a tight
moisture gradient over the center of the state. This makes precip
chances a little tricky for nrn lower. The best chances remain near
Saginaw Bay, with chances decreasing the further north and west you
go. Overall chances decrease west to east with time as drier air
filters in and upper level support and better moisture shift east.
Ern Upper is expected to remain dry through the day. Winds will
remain strong with gusts between 25 and 30mph. Winds shift more out
of the north overnight and with overlake instabilty we`ll have at
least the potential for some lake effect showers along Whitefish Bay
and the Lake Michigan coast. The only caveats to this would be
meager synoptic moisture and BL winds possibly having a slight
easterly component lingering behind the system, which would push
showers offshore.

Heading into Tuesday and Wednesday things quiet down quite a bit as
upper level ridging pushes into the area and a surface ridge axis
(extending from the 1030mb Hudson Bay high) passes overhead. Tuesday
will still be on the chilly (but normal) side, then Wednesday warms
back up into the mid-upper 50`s as WAA increases ahead of the next
trough moving through the Plains.
&&

.LONG TERM...(Wednesday night through Sunday)
Issued at 238 PM EDT Sun Oct 24 2021

High Impact Weather Potential...Minimal

Pattern Synopsis/Forecast...The western troughing becomes a cutoff
low over the southern Plains midweek, and this sets us up for some
warm/moist advection into Thursday. Guidance has been pretty
consistent with the deep cutoff setting up shop through the Ohio
and/or Tennessee Vallie`s with an associated surface low moving
through the Ohio Valley through late week. This lends to rain
chances looking pretty good through this time period, unless the
convection to our south robs us of the necessary moisture for
widespread rain. Mild late week temperatures should give way to
temperatures falling back into the upper 40`s by the weekend
(climatologically normal for late Oct) but this is a bit uncertain.

&&

.AVIATION...(For the 18Z TAFS through 18Z Monday afternoon)
Issued at 124 PM EDT Sun Oct 24 2021

Low pressure currently centered near the KS/NE/MO border will slowly
lift to the east-northeast across the mid-MS Valley this afternoon
through Monday. Any lingering isolated lake effect showers will
diminish this afternoon as our low-level flow continues to be
disrupted with winds veering more northerly, and eventually
northeasterly later this afternoon into tonight. As a result, lower
CIGS expected to develop off Lake Huron tonight with the potential
for MVFR conditions at APN/PLN. Some rain is expected to expand
northward tonight, with MBL having the best rain chances late
tonight before chances slowly increase at the TVC/PLN/APN during the
day Monday.


&&

.MARINE...
Issued at 238 PM EDT Sun Oct 24 2021

Low pressure currently centered near the KS/NE/MO border will slowly
lift to the east-northeast tonight through Monday. Early day
westerly winds have begun to veer more northerly early this
afternoon, and will continue to become more northeasterly by this
evening into tonight. Increasing gusts will continue to support SCA
conditions on most waters tonight through at least Monday evening
with at least some potential for some gale force gusts on the
nearshore waters of Lake Huron during the day Monday.

&&

.APX WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LH...SMALL CRAFT ADVISORY from 11 PM this evening to 11 PM EDT Monday
     for LHZ345.
     GALE WARNING from 8 AM to 11 PM EDT Monday for LHZ348-349.
     SMALL CRAFT ADVISORY from 2 AM Monday to 2 AM EDT Tuesday for
     LHZ346-347.
LM...SMALL CRAFT ADVISORY from 11 PM this evening to 11 PM EDT Monday
     for LMZ323-341-342.
     SMALL CRAFT ADVISORY from 8 PM this evening to 11 PM EDT Monday
     for LMZ344>346.
LS...SMALL CRAFT ADVISORY from 2 AM to 11 PM EDT Monday for LSZ321-
     322.
&&

$$

NEAR TERM...MG
SHORT TERM...STJ
LONG TERM...STJ
AVIATION...MG
MARINE...MG

NWS APX Office Area Forecast Discussion