786
FXUS63 KAPX 030747
AFDAPX

Area Forecast Discussion
National Weather Service Gaylord MI
347 AM EDT Wed Jul 3 2024

.KEY MESSAGES...

- A few thunderstorms producing locally heavy rain at times
  tonight.

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

- Heavy rain and possible stronger storms return for the weekend.

&&

.SHORT TERM /THROUGH TONIGHT/...
Issued at 347 AM EDT Wed Jul 3 2024

Pattern/synopsis: Low pressure in far nw Ontario, extends a
cold front sse-ward across western upper MI and eastern WI.
Trailing boundaries are found in ne MN and nw MN. One of those
crosses into upper MI late today.

Forecast: Well-defined MCV pushed an MCS across northern MI in
the late evening and early overnight hours. Trailing band of
associated convection is over ne lower MI. Continued warm/moist
advection is supporting additional showers pushing into western
areas, but this activity is lacking instability. Expect that to
comprise the final area of precip (for now). The back edge will
clear nw lower MI early this morning, and central and eastern
areas (including eastern upper MI) by noon. Partial clearing
follows by 2-3 hours.

However, cool/dry advection is weak at low levels, and surface
dew points will be maintained in the low-mid 60s today. Mid-
level drying and weak capping should be enough to keep a lid on
things in northern lower MI. But stronger sub-850mb convergence
will be found in the UP, along with cooler temps aloft. Spotty
convection is likely to develop by late afternoon down the
length of upper MI. MlCape values will push 500j/kg, with 0-6km
bulk shear of 40-50kt. Instability is the main limiting factor
for stronger convection, and am thinking severe storms are
unlikely over land. But perhaps a Special Marine Warning or two
is possible in the waters around eastern upper MI late this
afternoon into this evening.

How far s and e will a rain threat get this evening? CAMs are
generally inclined to kick off additional convection in nw/n
central lower MI, after dark. This might be ambitious, given
fading instability with time. But did mention a slight chance of
a shower late this evening in parts of northern lower MI (north
of an MBL-APN line). Otherwise partly cloudy to mostly clear
skies, and some patchy fog overnight.

Max temps today mid 70s to mid 80s. Lows tonight upper 50s to
mid 60s.

&&

.LONG TERM /THURSDAY THROUGH TUESDAY/...
Issued at 347 AM EDT Wed Jul 3 2024

Primary Forecast Concerns/Key Messages:

Split flow midlevel pattern spanning across North America will
continue active weather at times for the entirety of the long
term forecast period. Northern branch flow over the Canadian
Provinces will push midlevel shortwaves into the Great Lakes
region this weekend and early next week resulting in a cool and
(relatively) wet stretch of weather for the first week in July.

The first shortwave will progress into the Upper Midwest as early as
Thursday evening, developing surface low pressure along with
attached frontal boundaries. Showers and storms will persist Friday
into mainly Saturday before another upstream trough lowers into the
region next Tuesday. Large scale low pressure over Canada will
deepen by midweek next week and transition the northern CONUS to
a longwave troughing pattern through the remainder of the
forecast period.

Primary Forecast Concerns:

Dry conditions expected at the start of the long term
(Thursday/Independence Day). Conditions quickly return to a
wetter pattern this weekend: Current upstream shortwave ridging
will continue into the first day of the long term. Luckily for
everyone planning on enjoying the holiday, Independence Day
looks to remain dry, but upstream aformentioned troughing will
build cloud cover Thursday evening before returning showers and
storms as early as Friday morning. Biggest impact from this
event will be most locations seeing decent rainfall amounts from
the efficient transport of Gulf moisture into the Great Lakes
region. Most locations can expect a general half inch or so of
QPF, but locations near Lake Michigan can see higher amounts as
PWATs are expected to climb up to near climatological max. WPC
placed Northern Michigan under a marginal risk of excessive
rainfall, but the risk of flooding here will remain small.

Showers and storms are expected to continue at times next
week...Aformentioned continued midlevel pattern of troughing
next week will continue a quasi-active weather pattern to the
Great Lakes region next week. Best chance of rainfall will be on
Tuesday and Thursday as weak surface level low pressure
continues scatted showers at times for the remainder of the long
term.

&&

.AVIATION /06Z TAFS THROUGH 06Z THURSDAY/...
Issued at 1156 PM EDT Tue Jul 2 2024

Rain and embedded rumbles of thunder continue to spread across
northern Michigan as associated CIGs will lower tonight, and are
expected to drop to MVFR across most of the area shortly after 06Z.
IFR CIGs are also anticipated for many areas late tonight into
Wednesday morning. Brief drops to MVFR VSBYs will be possible within
heavier rainfall. Strong winds just off the surface lead to the
inclusion of LLWS across all northern lower Michigan TAF sites into
Wednesday morning. Cloud cover will clear from west to east as rain
chances depart Wednesday morning, leaving VFR conditions in place
from late morning/early afternoon Wednesday through the end of the
issuance period.

&&

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

&&

$$

SHORT TERM...JZ
LONG TERM...SJC
AVIATION...DJC