775
FXUS63 KAPX 072300
AFDAPX

Area Forecast Discussion
National Weather Service Gaylord MI
700 PM EDT Sun Jul 7 2024

.KEY MESSAGES...

- Scattered showers and thunderstorms Monday and Tuesday

- Uncertainty, in regards to rain, midweek.

&&

.SHORT TERM /THROUGH MONDAY/...
Issued at 246 PM EDT Sun Jul 7 2024

Pattern Synopsis and Forecast:
Upper level troughing currently resides over the northern
plains, stretching down to the central plains. Cooler air near
the surface is making its way southward over the Dakotas this
afternoon, with the cold front moving over MN/IA. This results
in SW winds aloft over MI, carrying the warm sector north.
Satellite depicts storms forming along a weak boundary ahead of
the front over SE WI, north of Chicago. This weak boundary will
move up towards northern lower tonight, being carried by SW
winds through the column ahead of the approaching trough.
Chances for showers will spread out over northern lower tonight
into early Monday morning with embedded thunder possible. Winds
turn mostly south to southwest Monday morning skies remain
mostly cloudy. Isolated to scattered showers and storms will be
seen Monday midday through the evening hours.


Primary Forecast Concerns:
Soupy air will move into the region tonight ahead of an
approaching upper trough. Surface dew points rise into the mid
to high 60s with PW values around 1.5" by Monday morning.
Soundings show much of the moisture being below 500mb.
Instability is limited to around 1000 j/kg (MU & SB), and
trailing off in the HGZ. Convective T is in the high 70s low 80s
around the CWA, which we will likely reach in most places
especially if the sun can poke through. Surface winds remain
weaker as the front remains to the west. This results in 0-1km
shear around 10 to 15kts, with ~ 30kts of 0-6km which sets up an
environment capable of producing storms that can become
organized, but limited shear exists for rotation near the
surface. This all supports a scenario of scattered showers and
storms Monday afternoon with a few being capable of producing
torrential rainfall and damaging winds. Small hail could also be
seen (and maybe a quarter could sneak by) with freezing levels
around 10 - 11 kft. HREF guidance shows chances for LCL heights
to drop to 1000ft (or even slightly below), which when paired
with the possibilities of locally enhanced wind shear a tornado
can`t be ruled out but chances remain low. Recent rains have
left most places with saturated soils, leading to flashy
responses of water with torrential rainfall. Sandy and saturated
soils leave trees more vulnerable to downburst winds from
thunderstorms. Storms Monday afternoon have the potential to
produce these winds and heavy rain, which could lead to trees
down and urban and small stream flooding. Make sure you stay up
to date with the latest forecasts and warnings.

&&

.LONG TERM /MONDAY NIGHT THROUGH SUNDAY/...
Issued at 246 PM EDT Sun Jul 7 2024

Pattern Synopsis and Forecast:

Very blocky, slow moving/evolving upper pattern across the CONUS-
portions of North America this upcoming week. Large ridge across
West Coast into western Canada (hence all the heat across CA-PAcNW),
and ridging across eastern seaboard as well to an extent. Weak
trough across the center of the county will eventually capture
Beryl, or the remnants, mid week and slowly move northeast/wash out
into the prevailing flow aloft. Where this happens, and subsequent
sfc low actually tracks will be all the difference and is uncertain
at this time. Heights are expected to rise thereafter in the
extended range next weekend resulting in warming temperatures.

Primary Forecast Concerns:

Troughing/lowering heights will be hanging around Monday night, thus
scattered showers and lingering thunderstorms likely early in the
evening. Temperatures warm aloft/lapse rates (whatever the antonym
of steepen here that flows well with the sentence), thus instability
will be weaker on Tuesday compared to Monday. In addition, source of
lift aloft largely weakens. Instability mainly remains confined to
eastern shores near Lake Huron and vicinity-southeast of there, thus
POPs reflect this in the forecast, with isolated to scattered
afternoon general thunderstorms. Weak, skinny instability and modest
shear will limit any appreciable severe threat.

Attention turns to tropical remnants, and really just the low
pressure and associated moisture, on Wednesday into Thursday. As
kind of expected, uncertainty remains in regards to impacts from
this feature, if any at all. Latest deterministic guidance seems to
shove the low pressure largely to the east of the region as an upper
trough "captures" this feature to the east of N MI. Ensembles show a
wide range of solutions from little to no impact, to lots of rain
(current GEFS 12Z guidance has a noticeable shift southeast).
Perhaps joining the dark side a little bit here, ECMWF AI model
bring this feature right up into MI, GFS AI farther southeast.
Furthermore, the ICON model, which has handled this feature as Beryl
exceptionally well to this point, skirts southeastern portions of
northern lower Michigan at this time. All this to say, the exact
interaction of the upper trough and the sfc feature will be key and
thus we remain in monitoring phase at this point. Based on some
shallow intuition here, think the most likely outcome will be the
south and eastern portions of the area to have the best chance for
seeing any appreciable rains Wednesday-Thursday, but confidence in
any outcome is very low at this time.

&&

.AVIATION /00Z TAFS THROUGH 00Z TUESDAY/...
Issued at 700 PM EDT Sun Jul 7 2024

Low level moisture and instability will gradually increase late
tonight thru Monday night in advance of an approaching cold
front. Chances of showers and thunderstorms will increase very
late tonight thru Monday night. Prevailing conditions will
remain VFR but will occasionally drop to MVFR/possibly IFR
within heavier showers/storms. SE winds under 10 kts tonight
into Monday morning will shift to the S/SW Monday afternoon.

&&

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

&&

$$

SHORT TERM...ELD
LONG TERM...JLD
AVIATION...MLR