360
FXUS63 KAPX 012300
AFDAPX

Area Forecast Discussion
National Weather Service Gaylord MI
700 PM EDT Mon Jul 1 2024

.KEY MESSAGES...

- Scattered showers Tuesday, a few breezes as well.

- Potential for more widespread showers and thunder (including
  heavy rainfall) Tuesday night into Wednesday.

- Trending dry for the Independence Day holiday (Thursday).

- Additional rain chances Friday into Saturday.

&&

.SHORT TERM /THROUGH TUESDAY/...
Issued at 235 PM EDT Mon Jul 1 2024

Pattern Synopsis and Forecast:

High pressure tonight will begin to slide to the east, moving to the
east into Tuesday due to troughing advecting eastward across central
Canada. High pressure will remain across portions of the CONUS east
and southeast, with southwest flow aloft increasing across northern
Michigan through the day. Energy aloft begins to slip into the
region riding this southwest flow within a warm air advection regime
and top down moistening. Best moisture and precip chances will be
into the overnight hours Tuesday but showery activity likely during
the day. Pressure gradient tightens and low level winds increase as
well.

Primary Forecast Concerns:

High pressure influence remains tonight, but begins to slide to the
east. Relatively cool night anticipated, but overall seasonable as
winds shift to the south and clouds begin to filter into northern
Michigan.

Warm air advection on Tuesday with an increase in moisture and
clouds. Additionally, southwest, increasing flow aloft spills over
the region. Another scenario with drier low to mid levels and thus
top down moistening during the day. As a result, precipitation
(reaching the ground) is anticipated to be light and spotty early,
but then increase in coverage as the atmospheric column saturates.
Pressure gradient will increase and thus mildly breezy conditions
expected as well, gusts occasionally up to 20 to 25 mph. Not a ton
of precipitation through the evening on Tuesday, upper end
probabilities via HREF & NBM 75th-90th%ile suggest ~0.1-0.25" of an
inch by the evening hours focusing, seems reasonable for spots west
of I-75. Better chances are expected shortly thereafter into Tuesday
night, read on for more information.

&&

.LONG TERM /TUESDAY NIGHT THROUGH MONDAY/...
Issued at 235 PM EDT Mon Jul 1 2024

Pattern Synopsis / Forecast:

Corridor of speedy 500mb flow between troughing over central Canada
and a ridge axis over New England will contribute a handful of
subtle vort maxes advecting into the upper Great Lakes Tuesday night
into Wednesday. Ample low level jet response (SW flow 45-55kts at
850mb) will draw deeper moisture plume into the Great Lakes ahead of
an approaching cold frontal boundary being forced eastward by the
troughing regime digging into the region and lowering 500mb height.
Result will be a period of showers and thunder Tuesday night into
early Wednesday as forcing becomes good enough to sustain persistent
rising motion overhead. This front will largely clear the area
through the day Wednesday, though with some diurnal heating and
lingering forcing owing to proximity to the surface low in northern
Ontario, could see a returning shower or rumble of thunder across
the eastern Yoop Wednesday afternoon. Post-frontal period of drier
weather expected on Thursday for the big holiday before another
trough digs into the northern Plains and drums up another moisture
response, just in time for the end of the week and into the
beginning of the upcoming holiday weekend.

Primary Forecast Concerns:

Tuesday night / Wednesday morning rain: Not much change overall in
the thinking, though some specifics are becoming a bit more clear.
While heavy rain is on the table, it`s beginning to look like it
will happen in brief bouts as opposed to repeated downpours. This
will be courtesy of potential shower / storm development across the
WI/IA/IL/MO vicinity basically intercepting the flow of the deepest
moisture, thus leaving us in the position to receive what can only
be described as the "convective leftovers" of much of this activity.
Still thinking a stripe of more enhanced rainfall can occur where
the 850mb forcing is best, driving a narrow corridor of elevated
instability... and just south of there, rainfall totals tail off
quite considerably, while areas north of this corridor see more
stratiform rainfall with perhaps a rumble of thunder. Latest
probabilistic guidance continues to paint the highest probabilities
of >1.00" of rainfall generally north and west of an HTL-APN line,
so not much change in where this localized max rainfall happens
since the previous cycle. Will probably need to fine tune this in
the next couple forecast cycles... there is some guidance that tries
painting this as basically the only rainfall Tuesday night, so it
could be one of those setups where some locales (especially south of
this focused corridor) see 0.10" or less of rainfall by the time
everything is all said and done by Wednesday evening. Continuing the
theme of the last several forecast cycles, flooding does not appear
to be of concern considering that this will be a bit of a drawn out
event, but given the high moisture volume throughout the atmosphere,
downpours will certainly be possible in any storms.

Wed. PM in the eastern Yoop: Some indications that low level
moisture will be a touch slow to erode from the atmospheric profile.
Given the passing of the cold frontal boundary and some diurnal
heating magic, wouldn`t be surprising to see some afternoon showers
/ thunder blossoming for our friends north of the Big Bridge when
coupled with lake breeze convergence. This activity is expected to
be scattered in coverage, so by no means a guarantee for rain, but
certainly can`t be ignored.

Independence Day: The big holiday itself will be dry as the cold
frontal boundary suppresses the deeper moisture (and thus, showers
too) to our south. Expecting highs to top out in the upper 70s to
mid 80s across the board. Should get through much of the evening on
the drier side, but as low pressure dips into Minnesota,
aforementioned frontal boundary will begin to lift back northward.
If any spot is going to see a chance of showers Thursday evening, it
will probably be areas closer to / south of M-55, though even for
these locales, chances are rather low.

Next weekend unsettled-ness: Aforementioned low pressure center will
continue to move a warm front through the region for the beginning
of the upcoming weekend. This system does appear to be an annoyingly
slow mover considering the high-activity weekend that revolves
around the holiday. Unfortunately, this will result in the return of
showers and perhaps some thunder Friday through Sunday... though at
this juncture, one positive is that it does not look like a steady
rain / washout... more of hit and miss showers. Will have to keep an
eye on this with time.

&&

.AVIATION /00Z TAFS THROUGH 00Z WEDNESDAY/...
Issued at 700 PM EDT Mon Jul 1 2024

High pressure will continue to gradually slide east away from
Michigan tonight...as low pressure developing to the lee of the
Rockies enters the Western Great Lakes region on Tuesday. Dry wx
will persist tonight into Tuesday morning...with only increasing
and thickening cirrus expected well in advance of the upstream
low. Chances of showers will increase Tuesday afternoon and
night as that system moves into Wisconsin and Michigan.
Prevailing conditions will remain VFR despite increasing clouds
and chances of showers. Light SE surface winds will strengthen
to 10 to 20 kts with some higher gusts on Tuesday.

&&

.APX WATCHES/WARNINGS/ADVISORIES...
MI...None.
MARINE...None.

&&

$$

SHORT TERM...JLD
LONG TERM...HAD
AVIATION...MLR