028 
FXUS63 KAPX 191737
AFDAPX

Area Forecast Discussion
National Weather Service Gaylord MI
137 PM EDT Tue Oct 19 2021

.UPDATE...
Issued at 1059 AM EDT Tue Oct 19 2021

Not a whole lot to update with high pressure to our south keeping
the region mostly sunny and unseasonably warm today. Southwest 
winds will pick up some and should average between 10 and 15 mph 
with gusts to near 20 mph this afternoon. Highs of well into the 
60s to the low 70s.

&&

.NEAR TERM...(Today through Tonight)
Issued at 351 AM EDT Tue Oct 19 2021

...Very Mild Mid-October Day...

High Impact Weather Potential: None. 

Pattern Synopsis/Forecast: 

Sharp mid level ridge in the process of building into the area early 
this morning. Per the usual, surface reflection running just a bit 
ahead of its mid level parent, with high pressure extending from the 
southeast states north into northern Michigan and eastern Lake 
Superior. Attendant deep layer subsidence regime and dry atmospheric 
column has resulted in a mostly clear and somewhat chilly 
night...with current readings dropping into the 40s, and even a few 
of our typical colder locations falling into the 30s (still at least 
a few degrees above normal however).

Mid level ridge expected to remain centered across the area today 
and tonight...although heights will slowly lower tonight as 
troughing digs across Ontario. Weak cold front tied to this latter 
feature will make slow southeast progress, likely pushing across 
eastern upper Michigan later tonight.

Primary Forecast Concerns/Challenges:

Main focus centered on temperature trends (or more precisely...just 
how warm to go today). 

Details:

Mid level ridge and attendant subsidence regime/dry atmosphere will 
result in mostly sunny skies today. Bigger story will be 
temperatures, with increasing southwest winds on north side of 
slowly retreating surface high advecting an unseasonably warm 
airmass into the Great Lakes. Dry low level environment and 
sun-filled skies easily support mixing to at least H9 level...where 
temperatures will be in the lower teens Celsius. This supports highs 
well up into the upper 60s and lower 70s...with those warmest 
readings expected across northeast lower Michigan where downslope 
influences will be maximized. For a comparison, normal high 
temperatures for today's date are in the lower to middle 50s. 
However, highs today will fall well short of any records, which are 
mostly in the upper 70s to near 80 for a climate locations.

Weak cold front slowly works southeast out of northern Lake Superior 
tonight, likely reaching vicinity Tip of the Mitt counties by 
sunrise Wednesday. All deep layer forcing is well removed to the 
north, and atmosphere only partially moistens ahead of the front. 
Both of these support dry conditions prevailing, although will 
likely see some increasing clouds...particularly across the north. 
Again, bigger story will be the continuation of well above normal 
temperatures...with those increasing clouds and maintenance of pre-
frontal southwest winds likely keeping at least portions of northern 
lower Michigan from dropping out of the 50s.

&&

.SHORT TERM...(Wednesday through Thursday night)
Issued at 351 AM EDT Tue Oct 19 2021

High Impact Weather Potential: Minimal attm...

Pattern Synopsis/Forecast:

Wednesday morning...complex upper level pattern will still be in 
place...with troughing to the west, north, and east of us. Ridging 
will continue to fade southeastward as the upstream trough over the 
northern Plains progresses in our direction with time...allowing an 
anomalously moist airmass to flood into the region yet again on 
southwesterly flow through the column. Meanwhile...strong troughing 
to our north will continue to dive southward and perpetuate a 
zonally-oriented surface boundary across our northwoods...keeping us 
in the focus for precipitation through much of the short term. That 
Plains shortwave should move through during the day Thursday...and 
as it passes through...will look for cold advection (generally 
associated with the upper low to our north as it begins to pivot 
down our way a bit) to bring a much cooler airmass into the region. 
Falling temps aloft Thursday night may even support lake effect 
shower development in some locations.

Primary Forecast Concerns: Rain/thunder potential Wednesday into 
Thursday...lake effect Thursday night....

Surface cold front extending from near Hudson Bay on the 
Manitoba/Ontario border as of 3z/19 southwestward into the northern 
Plains will become a focal point going into the short term portion 
of the forecast...as it looks to drape into the Straits area by 
Wednesday morning or so. As this front continues to slowly sink 
southward through the day, reinforced by cold advection to its north 
thanks to a 100+ kt upper-level jet max and surface high 
pressure...will look for it to stall out in the presence of 
southwesterly flow and warm, moist advection both at the surface and 
aloft ahead of the system in the Plains. The Plains low looks to 
progress eastward, more or less along this boundary, through 
Wednesday night and into Thursday...allowing the boundary to stall 
out in the vicinity of Northern Lower until such a time as the winds 
begin to turn more northwesterly again on the backside of the 
surface low and cold advection is allowed to proceed into the region 
unfettered...which looks to happen through the day Thursday into 
Thursday night. 

North of this zonally-oriented boundary on Wednesday...it should be 
cooler, though potentially with some mid-low clouds overhead (makes 
sense given some mid-low level moisture in place behind the same 
boundary at 0z/19 across the western Canadian Prairies) while areas 
south of the boundary will be in the warm sector of this system and 
should remain at least somewhat above normal for this time of year. 
With that anomalously moist atmosphere advecting in through the day 
(pwats again surging into the ~1" range, which is near the high end 
of climo for this time of year)...will look for top-down saturation 
to progress through the day...resulting in precipitation beginning 
towards the middle of the day at the earliest...though can't 
entirely rule out some stray stuff moving in during the morning 
hours. Better chances for rain, however, should arrive later in the 
afternoon/evening and so on as better synoptic forcing moves into 
the area with the approach of that shortwave aloft from the Plains. 

Suspect this will be more of a stratiform rain environment, given 
the lack of instability (save for some marginally steeper lapse 
rates aloft as the air aloft begins to cool with the approach of the 
upper level troughing)... though some guidance would like to bring 
in a few hundred joules of MUCape in the form of elevated 
instability, thanks to a stable layer in the mid-levels (beneath the 
aforementioned steeper lapse rates) given that warm advection ahead 
of the surface low/shortwave aloft. Will look for the best rain 
chances to be along and north of the front, where warm and moist air 
would be rising up over the cooler air near the surface.

The overall idea of stratiform precip with potential for a rumble of 
two should continue to be the case through the night Wednesday into 
Thursday, until the surface low passes by at some point Thursday 
afternoon. Wrap-around moisture behind the low...in combination with 
850mb temps falling below zero over sufficiently warm lake 
waters...should allow things to switch over to a more showery, lake-
effect regime Thursday into Thursday night...though some heavier 
stratiform precip may be possible right behind the low itself 
Thursday afternoon. Will have to keep an eye on this.

Despite cooler and drier air funneling into the region Thursday 
night, thanks to a reinforcing cold front associated with the trough 
to our north...with the lake as a source of moisture and 
instability...will be looking for that lake effect potential to 
start to pick up through the night. Thursday into Thursday night may 
be the first taste of real cold that we've seen thus far this 
season...with breezy conditions behind the departing and deepening 
surface low only adding to the chilly punch.

.LONG TERM...(Friday through Monday)
Issued at 351 AM EDT Tue Oct 19 2021

High Impact Weather Potential: Minimal attm...

Pattern Synopsis/Forecast: 

A decent amount of uncertainty is in place for the coming weekend 
and beyond...as there is a lot of model spread (and intra-model 
spread) in the handling of an anomalously strong trough over the 
eastern Pacific (which should be fed by a strong East Asian jet, 
stretching from Japan all the way to the West Coast of North 
America). It appears that between that trough, our trough, and the 
anomalous ridge that is progged to develop across Northern 
Canada...an omega block type pattern is ahead for the weekend. This 
should keep us on the cooler side of things for the most part, 
thanks to the downstream troughing side of the block hanging out 
over us. Various niblets passing through the flow would act to 
enhance any lake effect chances that occur (an idea with some merit, 
given the cool air aloft over the region and potential for over-lake 
instability)...though there is still some uncertainty in these 
little niblet-y details. Model solutions quickly diverge going into 
Saturday/Saturday night, in just how the pattern shifts (or doesn't) 
going forward. Even so...if everything lines up correctly (niblets 
pass through the region late in the day into the overnight, allowing 
for precipitation to take place during the colder nighttime 
period)...wouldn't be shocked to see the white stuff start to fall 
in some areas...though attm...suspect we'd be hard pressed to 
accumulate much at all, with the soil still warm (soil temps this 
evening at the office were in the low 50s 2" below the surface).

&&

.AVIATION...(For the 18Z TAFS through 18Z Wednesday afternoon)
Issued at 134 PM EDT Tue Oct 19 2021

High pressure will move slowly off to our east through tonight. A
weak, moisture starved cold front will then drop down from the
north Wednesday morning. Low pressure is expected to bring 
showers just beyond the taf period late Wednesday into Wednesday 
night. VFR cigs/vsbys through the period. Southwest winds of 5 to 
10 knots through tonight shifting into the west behind the front 
Wednesday morning. 

&&

.MARINE...
Issued at 351 AM EDT Tue Oct 19 2021

Southwest winds will be on the increase today as surface high 
pressure slowly retreats to our southeast. Increasingly stable over-
water conditions within an unseasonably warm airmass will likely 
negate small craft advisory conditions from developing. Weak cold 
front slowly drops southeast across Lake Superior and eastern upper 
Michigan later tonight, swinging the winds around to northwest as it 
passes. Otherwise, sub-advisory level southwest winds will continue. 
Front essentially stalls/washes out across lower Michigan on 
Wednesday...resulting in mostly light winds.

Dry weather is expected today and tonight, with increasing rain 
chances Wednesday and Wednesday night as low pressure pushes toward 
the region.


&&

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

$$

UPDATE...AS
NEAR TERM...MB
SHORT TERM...FEF
LONG TERM...FEF
AVIATION...AS
MARINE...MB