mi discuss
Office: MQT
FXUS63 KMQT 121139
AFDMQT
Area Forecast Discussion
National Weather Service Marquette MI
739 AM EDT Sat Jul 12 2025
.KEY MESSAGES...
- A Marginal Risk (category 1 of 5) of severe thunderstorms is in
place for the UP today with damaging winds and hail possible (5-15%)
as a warm front lifts north and a cold front pushes east.
- A Marginal Risk (category 1 of 4) of excessive rainfall is in
place for the UP today as rainfall totals over an inch may be seen,
especially in the eastern UP (40-80% chance).
- Some hazy/smoky skies expected behind the cold front this evening
as wildfire smoke from Canada is pushed towards the UP.
- Next chances for thunderstorms look to be with a cold front in the
Tuesday/Wednesday timeframe.
&&
.SHORT TERM /THROUGH TONIGHT/...
Issued at 416 AM EDT Sat Jul 12 2025
KMQT radar returns are showing two primary areas of precipitation
this early morning: a thin line of showers over the western UP and a
broad shield of showers across much of the eastern 2/3 of the UP.
The latter precip looks to be forced isentropically ahead of a
lifting warm front while the former is along a stalled cold front.
Model soundings do show steep midlevel lapse rates in the western UP
supporting up to 1000 J/kg of MUCAPE, however, flow is largely very
weak with sub-15 kt flow up to 400 mb, so despite some 50+ dBZ
returns being shown, much of the shower activity is quite
disorganized and not moving particularly fast. Should stronger
showers continue to remain for the next few hours while not moving
much, some attention will need to be given to hydrologic concerns as
the Porcupine Mountains in particular saw nearly 2 inches of rain
yesterday. Rainfall rates with the pre-warm frontal precip are much
lighter with MRMS suggesting around 0.05"/hr rates. Neither area of
precipitation has produced lightning yet, though LightningCast has
occasionally lit up with some 10+% threats of lightning with the
western showers.
Throughout this morning, flow aloft perpendicular to the cold front
will increase, allowing for the front to progress from west to east.
Meanwhile, the eastern UP will see some robust 850mb frontogenesis
which will support more robust shower activity with some embedded
thunderstorms. Whether either forcing mechanism will have enough
shear and instability to force strong to severe thunderstorms is
uncertain with each of the CAMs showing different coverage and
intensities of storms in the morning hours, but generally severe
weather is not expected as despite the increase in flow, shear is
not expected to have increased enough to keep storms organized as
well as it being too early for proper surface-based destabilization
to occur. Most CAMs do show a lull period around noon today as the
warm frontal shield lifts out of the eastern UP and convection
settles down in the western UP. This afternoon, as diurnal heating
allows for SBCAPE to climb to near 1000+ J/kg, the HRRR and NAMNest
do show robust convection reforming along the cold front in the
central UP. Should that occur, a marginal severe threat could be
realized, though much of the other CAMs show much more reserved
showers redeveloping, perhaps owing to paltry 0-3km SRH values
in the sub-50 range keeping things disorganized. Some attention
will need to be paid to the flooding potential in the east today
as HREF LPMM plots show the potential for 1-3+ inches of rain
to accumulate if embedded stronger showers in the warm frontal
zone are followed by more robust convection in the afternoon,
though the terrain and geology of the eastern UP makes it not as
prone to flash flooding as the western UP, and given training
is not expected with the second round, flooding concerns remain
marginal, though non-zero.
Besides the rain/thunder, expect high temperatures in the 70s today.
Air quality will be worth watching in the wake of the cold front as
prevailing winds shift to put the UP downstream of the northwest
Ontario/Manitoba wildfires with the post-frontal subsidence
pushing some of the smoke into the lower layers of the
atmosphere. Of particular note is the RAP-Smoke and HRRR-Smoke
resolving 35+ ug/m3 of near-surface smoke concentration, which
if it were to occur would push the air quality to levels
generally unhealthy for sensitive groups. Low temperatures look
to cool to around the 60 degree mark tonight as precip exits to
the east by 05Z Sunday.
&&
.LONG TERM /SATURDAY NIGHT THROUGH FRIDAY/...
Issued at 326 PM EDT Fri Jul 11 2025
The extended period starts off with quiet and generally dry weather
Sunday into Monday with surface ridging behind the exiting cold
front. However, a weak midlevel shortwave moving through later
Sunday may bring an increase in cloud cover, and some spotty rain
showers are not totally out of the question. Temperatures come in
slightly warmer, peaking in the lower/mid 80s both days across most
of the UP.
By early Tuesday, split flow sets up over the CONUS with mainly
zonal flow over the northern tier and sprawling ridging to the
south. Guidance is in agreement on broader troughing dropping from
the northern Prairie provinces into Ontario, and another, tighter
wave moving through British Columbia. There is also general
agreement on either a broad surface low or trough developing either
over Ontario or the Great Lakes, dragging a cold front through the
UP and bringing our next chances for showers/storms Tuesday into
WEdnesday, though differences in timing and strength persist among
guidance. After another brief period of ridging behind the front
Wednesday, the aforementioned western shortwave moves towards the
Great Lakes late next week, with another round of PoPs on the way.
After next week's cold front, daytime highs look to climb only into
the upper 60s to near 70 Wednesday onwards. Overnight lows are
largely expected to be in the 50s and 60s, with potential for may
interior locations to cool into the low to mid 40s behind next
week's front.
&&
.AVIATION /12Z TAFS THROUGH 12Z SUNDAY/...
Issued at 739 AM EDT Sat Jul 12 2025
Deteriorating weather conditions across the UP today as a warm front
lifts across the SAW vicinity and east while a cold front around the
CMX and IWD vicinity is also initiating showers with some TSRA
embedded within. All 3 sites will see some low MVFR to IFR
conditions this morning into the early afternoon before the cold
front's arrival brings higher ceilings but higher chances of TS. All
sites will clear out tonight (save for some smoke from Canadian
wildfires) with VFR prevailing through to 12Z Sunday. In the
immediate wake of the cold front, expect winds to become
northwesterly to westerly at up to 10 kt (potentially higher at CMX)
before backing slightly to southwest overnight tonight.
&&
.MARINE...
Issued at 326 PM EDT Fri Jul 11 2025
Winds generally remain below 15kts through tonight into early
Saturday. However, winds turning over to the WSW increase to around
20kts across the western half of the lake late Saturday with a
passing cold front. Winds remain elevated through Sunday before
falling back below 15kts Monday, then increase to around 15kts out
of the southeast Tuesday. This will coincide with some disturbances
moving through the Great Lakes Region over the weekend. With these
disturbances, showers and thunderstorms will overspread the lake
from west to east late tonight through Saturday. Further out,
additional shower and thunderstorm chances will accompany a Clipper
system late Monday through Tuesday. Also of note, patchy fog could
result in reduced visibilities across far western portions of the
lake tonight if we can pick up on any precipitation.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
Upper Michigan...
None.
Lake Superior...
None.
Lake Michigan...
None.
&&
$$
SHORT TERM...GS
LONG TERM...LC
AVIATION...GS
MARINE...LC
Office: DTX
FXUS63 KDTX 121103
AFDDTX
Area Forecast Discussion
National Weather Service Detroit/Pontiac MI
703 AM EDT Sat Jul 12 2025
.KEY MESSAGES...
- Showers and thunderstorms return this afternoon, capable of
isolated severe gusts to 60 mph and torrential rainfall which could
produce localized flooding.
- The combination of heat and humidity today will lead to max heat
indices in the upper 90s for Metro Detroit, prior to the arrival of
thunderstorms.
- Mainly dry and more seasonable temperature-wise Sunday, then
warming back into the 90s midweek.
&&
.AVIATION...
Warm and humid air entrenched across the area governS aviation
conditions today and at least through this evening. Patchy MVFR fog
to start is short-lived as mid July daytime heating quickly ramps up
this morning. Full VFR then leads to another round of thunderstorms
expected to blossom and feed off the heat and humidity this
afternoon and evening. Weaker showers/storms could begin by late
morning toward MBS and then expand in coverage and intensity through
the afternoon eventually affecting all terminals by late afternoon.
Expect numerous overall coverage with clusters of severe intensity
bringing potential damaging wind in addition to IFR/MVFR restriction
in heavy rainfall. This activity occurs ahead of the primary cold
front which could bring a stray shower or storm late tonight
followed by a short period of MVFR ceiling leading up to sunrise
Sunday morning.
For DTW/D21 Convection... An afternoon time window for thunderstorms
remains on schedule. Earlier initiation is possible toward MBS and
the northern reaches of D21 while timing of more direct impacts at
DTW is still closer to 21Z.
THRESHOLD PROBABILITIES...
* Low for ceiling 5000 ft or less outside of thunderstorms today and
this evening. Moderate with the cold front late tonight.
* Moderate for thunderstorms this afternoon.
&&
.PREV DISCUSSION...
Issued at 356 AM EDT Sat Jul 12 2025
DISCUSSION...
Periodic convection with renewed potential for some severe
thunderstorms returns today as an active pattern holds firm over the
Great Lakes. Upstream convection exits into northern Lower through
the remaining morning hours while mid-level is underway over
Southeast Michigan. Thermodynamic profiles are still supportive of
an elevated mixed layer with over 500 J/kg of MUCAPE before deep-
layer southwest flow slides into the region. A shortwave trough with
a 50+ knot jet core at 500 mb ejects across western Lower today and
starts to phase with a more amplified trough tilting from neutral to
negative over the Upper Midwest.
Main corridor of CVA should largely reside west of the forecast area
as midday convection starts to initiate, likely between 16Z and 18Z.
This activity predominantly develops along the CAPE gradient, in the
vicinity of the western CWA border. Main plume of instability,
marked by MLCAPE of 1000-1500 J/kg, will quickly blossom and
overspread Southeast Michigan through the early afternoon hours.
Surface reflection from the parent wave takes a more north-
northeasterly track which slows the advance of its attendant cold
front. Wind progs indicate the more pronounced south-to-west wind
shift closer to 06Z (Sunday), thus the pre-frontal surface trough
axis will serve as the more important dynamic mechanism to amplify
convection. Perhaps more importantly, the majority of the latest NWP
suite supports surface-based free-convection with ELs above 35 kft
once surface dewpoints revisit the lower 70s and 2m temperatures
jump to near 90F within the expanding warm sector. Shear parameters
are not overwhelmingly impressive, but remain sufficient to help
organize some linear structures. Severe threat still mainly focused
on wind hazards (isolated gusts to 60 mph) and torrential rainfall.
For what it's worth, ML data has carried higher severe wind
probabilities with run-to-run consistency. Also of note, prior to
the onset of precipitation, the greater Metro Detroit area could see
heat indices approach 100F, but it will be marginal since mid-70F
dewpoints appear to be the exception rather than the norm.
The front makes gradual inroads into Ontario late tonight which
corresponds to a drying locally, from west to east. Subset of CAMs
indicate a secondary storm response along the actually cold frontal
slope, but intensity should be significantly lower if this
materializes.
Post-frontal airmass characterized as cooler and drier for Sunday,
although temperatures should run near climatological averages (mid
80s). Can't completely rule out a few showers for the extreme
southeast portion of the CWA with the slowed boundary. Longer
wavelength trough axis aloft then backs the temporarily zonal flow
aloft with little sensible fanfare. A rebound in geopotential
heights is in store for next week as synoptic-scale anticyclonic
gyre organizes over The Southeast. This promotes moderating thermal
profiles with negligible storm potential Monday and Tuesday. Zonal
jet centered over the 50th parallel delivers a weak wave extending
into southern Lower Michigan as soon as Wednesday that could spur
convective activity. Model divergence has emerged in the medium-
range solutions for the extent of thermal troughing over the state,
but NBM output exudes confidence with a cold FROPA by Friday.
MARINE...
Renewed chances for showers and thunderstorms today ahead of and
along a cold front, which brings chances for strong to severe
thunderstorm development capable of producing wind gusts aoa 35
knots. Winds veer toward the southwest then continue toward the west
after the passage of the front. Mainly dry conditions and light
winds expected in the wake of the front, and through early next
week.
HYDROLOGY...
Some heavy showers and storms are likely today as a hot and humid
airmass builds back into the region. The environment will support
pockets of heavy downpours with rainfall rates possibly exceeding 2
inches per hour. Localized flooding concerns exist for some areas
that experience clustering of cells. Flooding threat will largely be
for small streams, low-lying roadways, and otherwise poorly drained
areas. Activity should wane from west to east early tonight as drier
weather settles in for the rest of the weekend and early next week.
&&
.DTX WATCHES/WARNINGS/ADVISORIES...
MI...None.
Lake Huron...None.
Lake St Clair...None.
Michigan waters of Lake Erie...None.
&&
$$
AVIATION.....BT
DISCUSSION...KGK
MARINE.......AM/KGK
HYDROLOGY....KGK
You can obtain your latest National Weather Service forecasts online
at www.weather.gov/detroit.
Office: APX
FXUS63 KAPX 121121
AFDAPX
Area Forecast Discussion
National Weather Service Gaylord MI
721 AM EDT Sat Jul 12 2025
.KEY MESSAGES...
- Showers and thunderstorms move over northern MI this morning
and will last through this afternoon. A few of these will be
capable of producing severe wind gusts and hail as well as
heavy rain and frequent lightning. Low chances for a tornado
or two with storms. Chances for severe threats confined to NE
lower.
- Winds become west Saturday night as drier air moves in.
- Seasonal temperatures with periods of mostly sunny skies and
periods of shower chances next week.
&&
.SHORT TERM /THROUGH TONIGHT/...
Issued at 243 AM EDT Sat Jul 12 2025
Current satellite and radar show an MCS moving over
IL/MO/MI this morning. Scattered showers are starting to reach over
parts of NW lower. These storms will continue into northern lower
this morning, brining brief heavy rain and lightening. Gusty outflow
winds up to 45 mph could also be seen from these storms. 00Z KAPX
RAOB shows PWATs of 1.62", with sites up stream around a tenth to
two tenths higher - this moist airmass will continue today. Weaker,
quasi-zonal midlevel flow over the central plains allowed for a
short wave to form earlier today over IA/NE. The MCS last night
allowed for amplification of that wave, and in turn a 30 - 50 kt
SW/NE orientated low to mid level jet formed over IA/IL/WI. This can
be seen in the higher tilts of those offices radar, as guidance over
the last 4 hours has started to pick up on this amplification. In
turn, a surface low forecasted to move through MI today deepens by 4
mb within the last 2 RAP runs - building confidence that there will
be better forcing available for storms later today.
The shortwave will phase with an upper level trough that moves over
MN today. This will drag the surface low with it towards eastern
upper around mid day today, which in turn pulls a frontal boundary
across northern lower this morning and into the afternoon hours.
Guidance shows features still being a little too disorganized and
forcing not aligned yet during the mornings hours today. This
results in very low chances of storms capable of producing severe
hazards as they move over NW lower this morning.
As the surface low reaches eastern upper, the sfc front will be
extended down through NE lower towards Saginaw Bay. At the same
time, vertically stacked waves at 850 and 700mb will orient a veering
profile in low level winds over this area. Low level winds speeds
are 30 to 40 kts, producing around 30 kts of 0 - 3 km shear - which
is enough to organize storms. Surface temperatuers will be rising
into the 70s and low 80s by mid day (especially where pockets of sun
can reach the surface), resulting in SBCAPE of around 2000 j/kg. A
window for storms being capable of producing large hail (up to an
inch or two), damaging wind gusts (up to 60 mph winds), and - with
low LCL heights - a weak tornado will be seen from mid day to mid
afternoon today over northeast lower. Most storms that move over
northern MI today will have periods of heavy (or even torrential)
rainfall with them, which could lead to ponding of water in low
spots and urban areas.
A secondary boundary will move over eastern upper late this evening
and into tonight, continuing shower and thunderstorm chances. Most
places will see brief heavy rain and lightning, with a storm or two
being capable of severe wind gusts and small hail.
&&
.LONG TERM /SUNDAY THROUGH FRIDAY/...
Issued at 243 AM EDT Sat Jul 12 2025
Drier air settles in Sunday, leading to mostly sunny skies with
seasonal temperatures. A trailing cold front will move through
Monday, brining mostly clouds to northern MI. The next chance
for rain will arrive mid week, right as temperatures as starting
to warm into the upper 80s. Chances for showers will linger
through the remainder of the work week.
&&
.AVIATION /12Z TAFS THROUGH 12Z SUNDAY/...
Issued at 649 AM EDT Sat Jul 12 2025
SHRA/TSRA and instances of +TSRA continue to stream
northeastward in the vicinity of the lake michigan shoreline,
dropping VSBYs to 2SM at times. BR/FG will continue for a few
hours as well, especially APN. Later this morning, AOB14-16Z,
activity will shift east for the most part with the focus
shifting towards APN. Instances of MVFR CIGs will continue into
the early portions of the afternoon, eventually becoming VFR for
most. Winds shift to the southwest today, with gusts up to 20KTs
outside of thunderstorm activity.
&&
.APX WATCHES/WARNINGS/ADVISORIES...
MI...None.
MARINE...None.
&&
$$
SHORT TERM...ELD
LONG TERM...ELD
AVIATION...JLD
Office: GRR
FXUS63 KGRR 121115
AFDGRR
Area Forecast Discussion
National Weather Service Grand Rapids MI
715 AM EDT Sat Jul 12 2025
.KEY MESSAGES...
- Severe Weather chances this Afternoon
- Showers and Thunderstorms return mid-week
&&
.DISCUSSION...
Issued at 343 AM EDT Sat Jul 12 2025
- Severe Weather chances this Afternoon
Shortwave trough axis goes negative tilt as it swings through
today with conditional severe threat across the eastern zones this
afternoon. Main threat will be isolated downbursts with deep layer
shear once again a limiting factor for persistent, organized
convection, despite 1500-2000 J/kg CAPE across the area from LAN
to JXN. Severe threat winds down in the late afternoon and early
evening as storms shift east.
- Showers and Thunderstorms return mid-week
Zonal flow with weak sfc ridging brings fair weather for Sunday
through Tuesday then rain chances returns for mid-week with the
approach of a weak shortwave trough. Showers and storms become
more widespread on Thursday as a cold front moves through. Severe
weather threat also increases as forecast deep layer shear is
progged to be over 30 knots along with sufficient instability for
organized storms.
&&
.AVIATION /06Z TAFS THROUGH 06Z SUNDAY/...
Issued at 115 AM EDT Sat Jul 12 2025
VFR conditions to prevail this morning then showers and
thunderstorms are expected to flare up Saturday afternoon over
roughly the eastern half of Lower Michigan with some isolated IFR
conditions in heavy rain along with winds gusting over 30 knots
and small hall in stronger storms.
&&
.MARINE...
Issued at 343 AM EDT Sat Jul 12 2025
Scattered thunderstorms today could bring wind gusts over 30
knots otherwise winds should be below 25 knots through the weekend
and into early next week.
&&
.GRR WATCHES/WARNINGS/ADVISORIES...
MI...None.
MARINE...None.
&&
$$
DISCUSSION...Ostuno
AVIATION...Ostuno
MARINE...Ostuno
