982
FXUS63 KAPX 162335
AFDAPX

Area Forecast Discussion
National Weather Service Gaylord MI
735 PM EDT Sun Jun 16 2024

.KEY MESSAGES...

- Chances for additional showers and thunderstorms tonight.

- High heat and humidity Monday through much of the work week.

- Periodic chances of showers and storms this week.

&&

.SHORT TERM /THROUGH MONDAY/...
Issued at 256 PM EDT Sun Jun 16 2024

Pattern Synopsis/Pattern Forecast:

Warm, moist advection continues across the Great Lakes early this
afternoon, driven by maturing southwest flow between expanding
southeast Conus centered subtropical ridging and broad troughing
digging into the Intermountain West. Subtle shortwave troughs racing
northeast within this deep layer southwest flow kicking off pockets
of showers and thunderstorms across the western Great Lakes.

Subtropical ridge/heat dome will continue to expand with time
through early this week, delivering a shot of true summertime heat
into the Great Lakes region.

Primary Forecast Concerns/Challenges:

Initial focus centers on shower/storm potential, especially through
tonight. Attention quicky turns to one of heat Monday.

Details:

Just one downright tricky (and thus low confidence) forecast with
regards to convection tonight. Plume of enhanced lapse rates and
attendant corridor of elevated instability set to fold across at
least the north half of the area tonight, with a well defined
mesoscale convective driven vorticity lobe expected to pass across
southern Michigan. Moisture profiles only become more impressive
with time, with precipitable water values expected to exceed 1.5
inches. Per the northern Michigan usual, uncertainty centers on a
trigger mechanism to utilize this convective potential.
Unfortunately, that is where all the unanswered questions remain.
Definitely not seeing any large scale forcing mechanisms to utilize
this potential...with best low/mid level convergence on nose of low
level jet looking to remain off to our northeast, best mid/upper
level jet support remaining off to our west/northwest, and forcing
from that MCV remaining off to our south. As previously mentioned,
suppose sustained moisture advection north of the partially modified
outflow boundary from current shower activity may be that trigger.
Again, where exactly that boundary locks in place and just how much
activity forms along and north of it remains a source of high
uncertainty. If convection does indeed materialize, moisture rich
profiles definitely supports some rather high intensity rainfall
rates, with any training of convection supporting some locally heavy
rainfall totals. Not completely out of the question for an isolated
severe storm, although lack of more defined wind fields through the
vertical argues otherwise.

Focus for Monday quickly becomes one of heat. Access to traditional
heat reserved for the south is fully realized, with thermal profiles
continuing to support widespread highs nearing/exceeding 90 degrees
across much of northern lower Michigan...with just slightly cooler
readings north of the big bridge and near those big bodies of water.
While not terrible excessive, low level moisture profiles support
dewpoints remaining in the 60s...only adding to how warm it will
feel. Still have some concern with convective debris clouds, along
with the potential for additional moist convection to fire during
the afternoon...especially across northeast lower Michigan (where
mixed layer cape in excess of 1k J/kg and enhanced low level
convergence will reside). Still expecting it to be unpleasantly warm
for most, and perhaps dangerously so for those working outdoors or
those with no access to home cooling.

&&

.LONG TERM /MONDAY NIGHT THROUGH SUNDAY/...
Issued at 256 PM EDT Sun Jun 16 2024

Pattern Synopsis/Pattern Forecast: Strong upper level high pressure
will be centered along the eastern seaboard over the next several
days. Northern stream troughing will attempt to knock down heights
across the western Great Lakes later in the week into next weekend.

Details:

Strong upper level ridging will be centered along the east coast
over the next several days. This ridge will extend westward into the
Great Lakes for a majority of the period. This will result in hot
and humid conditions through much of the work week. Heat indexes
will approach heat advisory criteria at times (100 degrees/3 hours),
especially across our southern counties. The area could see
occasional "cooling" thunderstorms develop either in the form of
convective systems possibly moving around the periphery of the ridge
or daytime heating/lake breeze induced. Whether or not this occurs
will be difficult to ascertain this far in advance unfortunately so
pops will stay in the chance category. As we head deeper into the
work week, northern stream energy will attempt to knock down the
ridge but guidance varies on the extent/timing of this possibility.
Highs of well into the 80s to the mid 90s (mainly south) are likely
through mid-week with highs of at least the upper 70s to upper 80s
likely later in the week. Perhaps more noticeable cooling will
arrive for next weekend.

&&

.AVIATION /00Z TAFS THROUGH 00Z TUESDAY/...
Issued at 735 PM EDT Sun Jun 16 2024

Warmer and more humid air will continue to press northward into
northern MI. Ongoing showers will dwindle over ne lower MI this
evening. Another round of SHRA and perhaps TSRA will advance
across upper MI later tonight, with precip possible at CIU
overnight. Mostly VFR otherwise.

S to sw winds overspread the area tonight and Monday. LLWS part
of tonight PLN/TVC/MBL.

&&

.APX WATCHES/WARNINGS/ADVISORIES...
MI...Air Quality Alert from midnight tonight to midnight EDT Monday
     night for MIZ020-025-026-031.
MARINE...Small Craft Advisory until 2 AM EDT Monday for LHZ346-348-349.
     Small Craft Advisory until 2 AM EDT Monday for LMZ344>346.
     Small Craft Advisory until 10 PM EDT this evening for LMZ323-
     341-342.

&&

$$

SHORT TERM...MSB
LONG TERM...AJS
AVIATION...JZ