260
FXUS63 KAPX 040742
AFDAPX

Area Forecast Discussion
National Weather Service Gaylord MI
342 AM EDT Thu Jul 4 2024

.KEY MESSAGES...

- Shower/t-storm chances increase late tonight into Friday.
  Locally heavy rainfall Friday.

- Active weather at times next week.

&&

.SHORT TERM /THROUGH TONIGHT/...
Issued at 343 AM EDT Thu Jul 4 2024

Happy 4th of July.

Pattern/synopsis: Low pressure over Hudson Bay will move ne-
ward. There are multiple surface trofs moving thru the northern
lakes, but the departing low will leave behind w-e oriented
troffing over the central lakes. Part of this can already be
analyzed as a warm/stationary front from eastern SD to central
WI. Aloft, a digging shortwave is likely to close off as it
transits southern MN tonight.

Forecast: Isolated showers are being maintained along a surface
trof that extends from south of LDM to north of APN. These will
persist for a few more hours, as they move eastward. Otherwise,
there are patchy mid clouds over eastern upper and ne lower MI.
Early on, surface heating will be relatively uninterrupted, and
temps will climb quickly this morning. We remain muggy (surface
dew points 60-65f), and that heating will eventually result in a
cu field. A partly cloudy afternoon is expected. Temps are warm
enough aloft to keep most of northern MI with minimal Cape. But,
where lake breezes move inland, and where moisture pooling
occurs along them, we may realize up to 300j/kg of MlCape. The
areas of interest are the interior of eastern upper MI, and ne
lower MI from Rogers to Standish. Isolated showers here are
maybe possible, late this afternoon into this evening. The grids
will have POPs around 10 percent, but this is not enough to
include a mention of a shower.

Tonight: as the upper low crosses southern MN, a weak surface
wave should take shape just ahead of it. A warm front sharpens
to the east of this (especially aloft), over southern WI. The
low level jet in the area is weakish, but a very rich airmass is
in the warm sector. Beginning late today, deep convection
should continue to generated in parts of MN/IA, and eventually
WI. Moisture/forcing/instability are all better west of Lake MI
than east, and CAMs are disagreeing considerably as to how far
east precip will get. Have kept the evening dry, before shower/
t-storm chances increase overnight. Highest pops are after
4-5am, west of I-75 in both peninsulas. Respectable precip rates
are possible...but are much more likely to be realized on
Friday and beyond.

Max temps mid/upper 70s north, to upper 80s far se. Lows mid 50s
to mid 60s.

&&

.LONG TERM /FRIDAY THROUGH WEDNESDAY/...
Issued at 343 AM EDT Thu Jul 4 2024

Primary Forecast Concerns/Key Messages:

Midlevel split flow pattern for the first half of the long term
followed by broader troughing next week will continue chances
of showers and storms at times throughout the entirety of the
forecast period. Embedded shortwaves will produce the best
chance of widespread rainfall across the CWA this weekend and
early next week.

The first trough with relatively weak surface low pressure currently
over the northern planes will progress to the Upper Midwest by late
Thursday night. The second main round of showers will not arrive
until Tuesday as an additional trough moves across the upper Great
Lakes region.

Primary Forecast Concerns:

Showers and storms return this Friday. Locally heavy rainfall
remains possible: Latest ensembles show weaker forcing compared
to past model runs along with lower H8 winds. With more
potential atmospheric stability and less southerly moisture
feeding into the CWA, lower QPF can be expected. The disheveled
core of low pressure is expected to track across central
Michigan, delivering a general half inch or so of QPF, but
locally higher amounts can be expected as PWATs remain quite
juicy (well over an inch).

Longwave troughing will keep chances of active weather at times
next week: Aformentioned split flow followed by longwave
troughing across the northern half of north America will keep
active weather at times for the remainder of the forecast
period. Best chance of widespread rainfall is on Tuesday as
another shortwave drops from northern Hudson Bay to the Upper
Great Lakes. Longwave troughing after Tuesday will keep chances
of diurnal pop-up thunderstorms like a typical northern Michigan
summer.

&&

.AVIATION /06Z TAFS THROUGH 06Z FRIDAY/...
Issued at 1147 PM EDT Wed Jul 3 2024

VFR conditions look to persist across northern Michigan through the
issuance period. A few showers working across the eastern U.P. and
far northern lower will continue to diminish/depart east over the
next few hours. There is a low chance for localized patchy FG/BR
tonight, but confidence is not high enough to include in the TAFs
(primarily at MBL) at this time. Otherwise, west to northwest winds
around 5-10 kts are anticipated through tomorrow with lake breeze
formation likely to push inland from Lake Huron in the
afternoon.

&&

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

&&

$$

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