000
FXUS63 KAPX 081414
AFDAPX

Area Forecast Discussion
National Weather Service Gaylord MI
1014 AM EDT Mon Aug 8 2022

.UPDATE...
Issued at 1014 AM EDT Mon Aug 8 2022

Pockets of heavy rainfall continue to move across portions of
northern Michigan this morning. A couple of reports so far this
morning of around 2 inches of rain in Leelanau County. Would
expect similar totals along the M-32 corridor with the batch of
heaviest shower and embedded storm activity over the next couple
of hours. Progressive nature of this rainfall should keep flooding
from getting too out of hand, but some low-lying and roadway
ponding certainly not out of the question.

Moving forward, latest trends suggest the bulk of this rainfall
moves east by early-mid afternoon with lingering low clouds and
some patchy drizzle left over.

&&

.NEAR TERM...(Today and tonight)
Issued at 113 AM EDT Mon Aug 8 2022

...More showers, especially this morning...

High Impact Weather Potential: Minimal. Will need to be on the
lookout for some locally heavy rain at times. A few non-severe
thunderstorms possible as well.

Pattern Synopsis/Forecast:

Cold front responsible for yesterdays showers now just off to the
south of our forecast area...stretching west to east across central
Lower Michigan. Weak low pressure developing on the western extent
of this front back across Iowa, made to so by sharp shortwave trough
rotating across Minnesota. Nice area of showers and embedded
thunderstorms firing out ahead of this wave as deep moisture
interacts with increased forcing for ascent. Not nearly as active
yet across our area, with noted mid level drying (nicely displayed
on our local 00z sounding) having largely ended the shower threat.
Still plenty of lower level moisture across northern lower Michigan,
producing a dense low overcast, areas of fog and mist, and even some
drizzle. A bit more aggressive drying to the north of the big
bridge, with even some clear skies for a bit this past evening.

All eyes focused on that incoming fast moving wave. Expect this wave
to race east across our area today (albeit dampening in the
process). Deep layer response ahead of this wave will help drive
that central lower Michigan front back north quickly this morning as
weak low pressure rides up along it. Mid level dry tongue will
quickly depart in the process, with a return of deep layer
saturation across northern Michigan. Combine this with that passing
low and increasing vertical ascent via right entrance region upper
jet dynamics, and the stage is set for another round of rain and
embedded thunderstorms today.

Primary Forecast Concerns/Challenges:

Main focus and shower and thunderstorm evolution today. Heavy rain
potential will also need to be addressed.

Details:

Expect showers to expand quickly back into the area this morning as
deep layer forcing increases, with rain steadily ending from west to
east through the afternoon as low pressure departs off to our east.
Should be a fairly widespread area of rain given said forcing
working on a moisture rich environment. Little doubt some briefly
heavier rainfall rates will be realized given precipitable water
values surging back up to, and even a bit over, 2 inches and
respectable warm cloud depths (makes for some efficient rain
processes...like we saw yesterday). Cape is very limited, but gotta
believe there will be at least a few embedded thunderstorms given
amount of forcing. Easily would expect at least inch per hour
rainfall rates, especially with any of those embedded storms.
However, as already evident by upstream radars, this area of rain
will be on the move, significantly limiting the overall duration of
any heavy rain. Thus, just not seeing any widespread significant
impacts with this rain. Something to of course monitor, as any
longer duration of heavier rains than currently anticipated may
result in some more significant impacts.

Simple extrapolation supports rains having exited stage right by
late this afternoon and early evening. Suppose we might see a bit of
post-frontal drizzle this evening as low level moisture takes a bit
longer to depart. Aggressive drying does kick in during the
overnight, with skies clearing from the northwest. Definitely a
cooler and much less humid night, with widespread lows in the lower
and middle 50s.

&&

.SHORT TERM...(Tuesday through Wednesday)
Issued at 242 AM EDT Mon Aug 8 2022

High Impact Weather Potential: Minimal attm...

Pattern Synopsis/Forecast:

Broad anticyclonic flow across the central CONUS has become less
broad over the last 24 hours, focusing itself more over the Midwest
as of 02z/08...with continued southwesterly flow aloft from the
Desert Southwest up into the Upper Great Lakes along the backside of
this shallowly-positively-tilted upper level ridge. Subsidence along
the downstream side of this ridge is less noted attm...and do still
note a little vorticity maximum still slowly meandering eastward
into the Mid-MS Valley south of the ridge. Watching a potent little
shortwave trek across the Northern Plains/International Border
attm...with some shear vorticity stretching across southern Canada
north of this feature, stretching eastward to the troughing that
passed by to our north Saturday night, along which a 100-120+kt
upper level jet is noted to our north through Ontario, stretching
back to the cold pool aloft associated with our potent shortwave
across the Dakotas/MN as it crashes into the warm air mass over us
attm. Additional, weaker bits of vorticity slipping down from the
Canadian Rockies behind this as well, with ridging rebounding across
the western US as a cutoff low swirls just off the coast of
California; a bit of weak surface troughing noted across
Saskatchewan with some of these features. Air mass along our
boundary beneath the ridge remains overly moist...with pwats in the
2+ inch range (0z/08 sounding at APX...1.90 inches, GRB...2.12
inches), which remains at or above the high end of climo as WSW-ENE
axis of anomalous moisture lingers along the boundary over us;
surface dewpoints in the 60s and 70s along and south of this
boundary. (Ew.) Mainly just drizzly showery activity over northern
MI attm beneath broad signals of ascent in water vapor
imagery...with some convective activity developing to our west in
IA/MN as of 2z related largely to incoming shortwave trough.
Boundary over our area sank south a smidgen through the day, still
largely bifurcating the fingers from the remainder of the Mitten as
of 0z/08; with signals of a surface response to incoming shortwave
trough aloft...as kink in the thermal gradient/boundary across
western IA becomes more noteworthy with time. Boundary continues
southwestward through the Central Plains from there, weaving its way
back northward along the Lee of the Rockies in Colorado/Wyoming
along the thermal gradient there.

Looking ahead...shortwave slips through the region today, driving
some surface response along the boundary into northern Michigan
before departing the region through the day. Still looking at
signals for energy to slide down out of central Canada tonight into
Tuesday, with high pressure settling into our region ahead of it.
Bulk of the energy and surface response with this feature looks to
remain to our north attm...but does appear a BCZ will slip in with
this later Wednesday into Wednesday night, so will keep an eye on
this. Meanwhile...upstream...cutoff low spinning off the West Coast
attm will eventually make its way toward the coast going into the
middle of the week...helping amplify the upper level pattern across
the CONUS yet again.

Primary Forecast Concerns: Dry conditions Tuesday...return of
rain/storm chances Wednesday-Wednesday Night...

Relatively light winds anticipated Tuesday, generally from the
north, with lake breeze development during the afternoon as we heat
up...most notable across NE Lower. Things should remain pretty light
Wednesday...but more west to southwesterly ahead of the incoming
front, potentially a little gustier at times (upwards of 15-20kts)
right in advance of the front as winds aloft pick up a bit and
diurnal heating allows for better downward momentum transport.

As shortwave and surface boundary depart the area tonight...looks as
though a bit of troughing aloft will remain...in combination with
some signals for lingering boundary layer moisture...so I have some
suspicions that we could see a little diurnal cu develop during the
afternoon. Overall, though, the air mass appears much drier than the
current over-saturated sponge sitting over the Great Lakes...perhaps
actually a little on the anomalously dry side, which should be a
relief as far as humidity goes...and may be a concern with regard to
fire danger (strictly from a meteorological criteria standpoint;
weekend/early-week rainfall notwithstanding) as it wouldn`t be out
of the question for afternoon highs to get into the low 80s. Not
sure how hard we will want to message this to the public (will
certainly pass on to fire partners), but will ultimately depend on
the amount of rain we get.

Wednesday could be a little interesting, with some guidance
suggesting the shortwave diving into the backside of the trough and
its surface reflection could drive some convection during the
afternoon/evening hours as it drops southward with time. Already
seeing some signals for forcing/tightening of the thermal gradient
with this boundary on strengthening northerly flow behind this
feature...with some increase in moisture as it drops
through...though will have to contend with the antecedent dry air
mass over the region from Tuesday. With the cooling air aloft
associated with this shortwave, am not surprised to see signals of
steeper mid-level lapse rates with this feature in some guidance, so
will have to keep an eye on this. Attm...looks like the bulk of the
strongest winds aloft Wednesday will be behind the feature, but it
will still bear watching as we go forward. Will look for at least
some chance at rain and thunder (given potential for elevated
instability, with the steeper lapse rates). More details to come as
they become clearer in the next couple days...as guidance is still a
little waffly on things attm.

.LONG TERM...(Wednesday night through Sunday)
Issued at 242 AM EDT Mon Aug 8 2022

High Impact Weather Potential: Minimal attm...

Pattern Synopsis/Forecast:

As we go into Thursday and bowling ball of upper level energy moves
into the Pac NW, our own troughing energy will be settling into the
Great Lakes/eastern US/Canada, leading to cooler conditions for the
other side of Hump Day, with largely northerly flow as Canadian high
pressure attempts to settle into the region behind some niblets of
energy dropping through the flow, as upstream pattern amplifies.
Ridging looks to set up across the center of the country, poking up
into the central Canadian Prairies for a time toward the end of the
week, with signals for the West Coast low to try to make its way
over the ridge this weekend. Things become more unclear going into
the weekend, but do see some signals for northern stream energy to
attempt to slip into the troughing somehow this weekend...which may
be something to keep an eye on. Suspect things will overall be
pretty decent for the bulk of the period, though...and likely pretty
dry for the end of the week, given some signals for an anomalously
dry air mass to drop in (which makes total sense, given this will be
coming down from central Canada). So will let consensus guidance
prevail for now...

&&

.AVIATION...(For the 12Z TAFS through 12Z Tuesday morning)
Issued at 616 AM EDT Mon Aug 8 2022

IFR conditions to remain rather persistent today as weak low
pressure slides across northern Michigan. Band of showers with
embedded thunderstorms will slide rapidly east across the taf
locations this morning, with showers ending from west to east this
afternoon. Some of the rain could be heavy, lowering visibilities
at times. Slow improvement in the low cloud deck expected tonight,
with skies finally attempting to scatter out toward Tuesday
morning.


&&

.MARINE...
Issued at 242 AM EDT Mon Aug 8 2022

North/northeast winds become quite gusty behind quickly departing
low pressure today. Expect small craft advisory conditions on at
least some of our Lake Michigan nearshore waters. Winds gradually
subside tonight, with light and lake breeze dominated winds
returning for Tuesday. Widespread showers develop this morning,
ending from west to east this afternoon. Dry weather returns
tonight, with trends supporting mostly dry weather continuing
through the remainder of the week.


&&

.APX WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LH...NONE.
LM...SMALL CRAFT ADVISORY until 8 PM EDT this evening for LMZ323-342-
     344>346.
LS...NONE.
&&

$$

UPDATE...MJG
NEAR TERM...MSB
SHORT TERM...FEF
LONG TERM...FEF
AVIATION...MSB
MARINE...MSB

NWS APX Office Area Forecast Discussion