Forecast Discussions mentioning any of "HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 09/05/24

Area Forecast Discussion

National Weather Service Aberdeen SD

 713 PM CDT Wed Sep 4 2024

.KEY MESSAGES...

- Cool dry Canada-sourced surface high pressure builds over the
  region through Thursday night, resulting in near to below
  normal temperatures, and perhaps a little bit of near surface
  smoke tonight into Thursday morning.

- Dry conditions with above average temperatures can be expected
  Sunday through at least Wednesday.

&&

.UPDATE...
Issued at 712 PM CDT Wed Sep 4 2024

Ongoing light showers continue over central SD, with little to
lightning will continue to track east. The current forecast looks
to be on track with smoke (or a mix of light rain and smoke)
reducing visibility at MBG and PIR to 5 miles.

&&

.SHORT TERM /THIS EVENING THROUGH THURSDAY NIGHT/...
Issued at 244 PM CDT Wed Sep 4 2024

At 2 PM CDT, skies are partly to mostly cloudy and there have been a
few WAA-forced elevated showers over parts of central and north
central South Dakota over the past several hours. The surface warm-
front/pre-frontal surface trof has made it all the way to the James
River valley and is attempting to overcome the Prairie Coteau.
Meanwhile, the cold front/CAA has made minimal progress southeast
into the CWA, stalled a bit until the better NVA/subsidence/forcing
for cold-fropa (still back over the Black Hills/nern Wyoming) moves
over the CWA. Temperatures within the "warm sector" and area east of
the warm front are warming through the upper 70s to mid 80s right
now. Behind this cold fropa over north central South Dakota,
temperatures are in the low to mid 70s. The RAP model has a small
ribbon of higher 850hpa dewpoints along this cold frontal boundary,
which is aiding in the development of ~500-1200J/kg CAPE. SPC
analysis shows deep layer shear on the order of 30 to 35 knots.

Will continue to see spotty WAA-forced showers moving northeast
across the region through early this evening. There could still be a
storm or two developing along this cold frontal boundary southeast
in the CWA this evening. Hi-res CAM output is highlighting a brief
period of northwest flow shower potential Thursday morning.
Otherwise, the forecast through Thursday night should be dry within
increasing influence of surface high pressure. Also worth noting,
upstream surface obs in western North Dakota back into Montana have
been reporting a reduced surface visibility (near surface wildfire
smoke), which the HRRR smoke model has been doing okay modeling. The
HRRR smoke model advects some of this smoke down into the CWA
tonight into Thursday morning. So, have introduced some patchy smoke
mention in the forecast for tonight.

The low level CAA event in progress will persist into the day on
Thursday as a 1030hpa surface high moves in. This will knock
925hpa/850hpa air temperature down to or slightly below climo normal
for early September (normal: ~77-83F). Thursday night lows will fall
below normal (normal: ~52-55F).

&&

.LONG TERM /FRIDAY THROUGH WEDNESDAY/...
Issued at 244 PM CDT Wed Sep 4 2024

Deterministic models show a trough moving southeast over eastern SD
on Friday. They also have mid-level moisture and CAA over northeast
SD through Friday afternoon, and with the forcing from the upper-
level trough moving over, the EMCWF has light rain showers
developing over eastern SD and western MN counties Friday morning
into the afternoon. Other models do not have precipitation
developing because their mid-levels are a bit drier, however, the
NBM displays single digit PoP values over the area during this time,
which is an increase from previous runs, showing that there is some
faint signal for precipitation to develop over the eastern side of
SD. Even if precipitation doesn`t develop, the CAA that is over
northeastern and central SD will be bringing cooler temperatures to
the surface. The NBM indicates that these temperatures will be about
7 degrees below average through Friday evening.

Once the trough moves southeast out of SD, the clusters and
deterministic models have northwest flow over SD as ridging develops
over the state. By Monday evening/Tuesday morning, the models have
moved a shortwave overtop of the ridge, changing the flow to be
westerly. This continues until the shortwave moves to the east and a
high pressure, with northwest flow, affects SD again. While the
upper-levels have, on average, a more northerly flow, the mid-level
are showing a more southwesterly flow over SD bringing in warm, dry
air. Without moisture, the models do not develop any precipitation
till the end of the forecast period. Additionally, the WAA over SD
will lead to a warming trend in temperatures at the surface with the
NBM generating temperatures 10 to 15 degrees above normal by
Wednesday.

&&

.AVIATION /00Z TAFS THROUGH 00Z THURSDAY/...
Issued at 712 PM CDT Wed Sep 4 2024

Terminals KABR,KATY,KPIR,KMBG

Expect smoke to continue to be a concern, with smoke or a mix of
smoke and light rain reducing visibility over central SD (MBG/PIR)
to 5 miles. A reduction of 5-6 miles will be common at all TAF
sites over the next 24 hours, getting to ATY after 05Z, after
winds switch out of the north. Otherwise, light rain will be
possible, mainly at PIR and ABR. Confidence is lower as to if
showers will continue to make it to ATY by around 04Z, so have not
included a precipitation mention there yet.

&&

.ABR WATCHES/WARNINGS/ADVISORIES...
SD...None.
MN...None.
&&

$$

UPDATE...KF
SHORT TERM...Dorn
LONG TERM...Vernon
AVIATION...KF




Area Forecast Discussion

National Weather Service Columbia SC

 1032 PM EDT Wed Sep 4 2024

.SYNOPSIS...
Weak low pressure in the Gulf of Mexico and along the Carolina
coast may spread showers into the area Friday into Saturday.
High pressure and a much drier air mass build in Sunday into
next week.

&&

.NEAR TERM /UNTIL 7 AM THURSDAY MORNING/...
Key Message(s):

- Isolated showers in the east Midlands this evening.

Low-level easterly flow is resulting in warm advection/shallow
moisture flux into the area. A few showers in the Coastal Plain
are moving into the east Midlands at 22z. The HRRR and RAP
suggest the showers will move west and weaken with time. Raised
pops in the east Midlands through the early evening.

Strong surface ridge centered over the Mid Atlantic will extend
into the region overnight. The pressure gradient remains
relatively tight. Expect some mixing in the boundary layer to
keep temps up a bit. Expect increasing strato-cumulus through
the overnight. Guidance temps consistent with temps warmer than
last night, mainly mid to upper 60s.

&&

.SHORT TERM /7 AM THURSDAY MORNING THROUGH FRIDAY NIGHT/...
Key Message(s):

- Increasing rain chances Friday night
- Continued cooler than normal temperatures

Thursday and Thursday night: Generally westerly 500mb flow
persists across our area on Thursday ahead of a strong upper
trough that will be digging into the upper Midwest and Great
Lakes region. Another upper weakness over the lower MS Valley
will gradually begin shifting eastward. At the surface, strong
high pressure also remains in place, centered just off the New
England coast ridging into the Carolinas. Expect another cool
and dry day across the region with atmospheric moisture near
normal with a PWAT gradient from around 1.4 inches north to 1.7
inches south. In the absence of much forcing and a stable
atmosphere in place due to easterly low level flow, expect most
of the area to remain rain free. Temperatures should remain
below normal with a combination of lower and mid/high clouds
limiting solar insolation with highs expected in the upper 70s
to lower 80s. Overnight lows Thursday night should be in the
60s.

Friday and Friday night: Rain chances increase on Friday into
Friday night as the upper weakness over the MS Valley phases
with the digging upper trough that moves over the Great Lakes
into the Ohio Valley region. 500mb flow backs more southwesterly
Friday with increasing moisture across the region as PWATs rise
to around 120 to 140 percent of normal Friday night (supported
by ensemble PWATs at the 99th percentile) with increasing large
scale ascent. This should result in rain developing by Friday
afternoon moving into the CSRA and expanding northeastward
across the forecast area Friday night. Short and long range
ensemble QPF has been increasing each of the past several model
runs increasing confidence in measurable rain, especially
across the CSRA and southeast Midlands. Will increase pops
further with this forecast but keep pops in the chance range
across the northern Midlands. Ensemble QPF indicates rainfall
amounts generally between a quarter and half inch with some
locally higher amounts up to an inch with a gradient from lower
amounts north to higher amounts southeast. Temperatures continue
to be well below normal with expected cloud cover and increased
chances of rain with highs in the upper 70s to lower 80s and
lows in the 60s.

&&

.LONG TERM /SATURDAY THROUGH WEDNESDAY/...
Key Message(s):

- Relatively benign weather after Saturday
- Dry conditions expected with near to below normal temperatures

Morning rain is expected Saturday morning, at least across the
eastern Midlands and lower CSRA, as a weak low develops along
the baroclinic zone off the coast and then lifts northeastward
through Saturday night. Expect decreasing pops through the day
from west to east and some possible late day clearing as drier
air begins to work into the region as the upper trough axis
swings through the region. A cold front will push through from
the northwest by Saturday night before stalling along the coast.
Temperatures on Saturday will be challenging depending on how
quickly rain moves out of the region and how much clearing
occurs but expect warmer highs to be in the western Midlands
where clearing should occur first.

The remainder of the extended period is expected to be dry with
GEFS/EPS showing a positively tilted upper trough extending
from New England down the east coast through the week and
anomalously strong surface high pressure building eastward from
the MS Valley into the Ohio Valley early next week. This should
bring a much drier air mass to the region with dewpoints
expected in the 50s much of the week and PWAT values around
50-60 percent of normal. Temperatures look to be below normal
with large diurnal trends given the dry air mass in place with
highs in the lower 80s and lows in the 50s to lower 60s.

&&

.AVIATION /03Z THURSDAY THROUGH MONDAY/...
VFR Conditions Likely to Continue for Much of the TAF
Period....

SCT to BKN low to mid level cloudiness continues to move across
the forecast area from the east this evening though all
terminals are reporting VFR conditions at this time. High-level
clouds are also moving in from the west so skies will likely be
BKN to OVC for much of the TAF period. Tranquil weather is
expected during the overnight hours though there is a low chance
for MVFR ceilings to develop towards daybreak, especially at
OGB. Thursday looks to be another dry day with periodically
gusty winds in the afternoon.

EXTENDED AVIATION OUTLOOK...Showers and thunderstorms become
more likely by Friday with associated vsby and cig restriction
likely.

&&

.CAE WATCHES/WARNINGS/ADVISORIES...
SC...None.
GA...None.

&&

$$




Area Forecast Discussion

National Weather Service Sioux Falls SD

 1019 PM CDT Wed Sep 4 2024

.KEY MESSAGES...

- Low chances (30% or less) for showers and storms this evening
  and tonight behind a cold front moving through the area.
  While unlikely, a stronger storm or two is possible in south
  central SD west of the James River after midnight.

- Roller coaster of temperatures continues, with cooler weather
  late this week and above average temperatures returning early
  to mid next week.

- Wildfire smoke aloft progresses south tonight through
  Thursday night, with surface smoke advecting in as well
  tonight and tomorrow. Those who are sensitive to the smoke
  should take precautions to limit exposure.

&&

.DISCUSSION...
Issued at 236 PM CDT Wed Sep 4 2024

REST OF TODAY AND TONIGHT: Cold front continues to slowly move east
across the area this afternoon and evening. Some concern that
today`s forecast high temperatures may be overdone for portions of
south central SD, but we seem to be mixing out well ahead of the
front with breezy southerly winds. We`ll continue to warm today into
the mid 80s to lower 90s, warmest across the southern James Valley
ahead of the cold front. Winds continue to gust to 30 mph through
the evening as well, shifting from southerly to northwesterly as the
cold front passes tonight into early Thursday.

Hi-res guidance continues to show isolated to scattered showers and
isolated storms this evening through the overnight hours into
Thursday morning, mainly focused behind the surface cold front near
the mid/upper level trough axis. As of 04.19z (2 PM CDT), convection
indeed remains focused across western NE/SD into central/eastern ND
with the trough axis/elevated front. Not expecting much - if any -
convection to develop along the surface front due to the capping in
place. Convection will also likely struggle into the late afternoon
just behind the front due to the cap as well, waiting for the better
forcing from the elevated front/trough axis. Although it can`t be
entirely ruled out, severe weather remains very unlikely for a few
reasons. Capping will limit convective development and parameters
are displaced from one another (with the best instability ahead of
the surface front and the better shear back toward the elevated
front). Any stronger storm could produce wind gusts to 60 mph and
hail to quarter size.

Will also be keeping an eye on any stronger development late in the
overnight toward daybreak Thursday, as there is an increase in the
LLJ. Not sure we`ll have enough moisture along the elevated front to
lead to more widespread activity than currently expected, but may be
something worth keeping an eye on. Otherwise, lows tonight fall into
upper 50s to mid 60s.

THURSDAY-THURSDAY NIGHT: Lingering showers and isolated storms are
possible through the day on Thursday behind the surface front and as
the mid/upper level trough swing through the north central Plains.
Precipitation may linger into the afternoon hours east of I-29,
although some hi-res guidance has isolated development area-wide
through the day. Confidence is low in that potential, so have
limited pops to the anticipated post frontal activity. Northwesterly
flow and CAA prevail, leading to a cooler day. Dropped highs a
couple of degrees from the previous forecast, due to lingering cloud
cover and wildfire smoke aloft. 04.12z guidance is a bit more
aggressive with the concentration of surface smoke, and looking at
surface observations in ND, it`s easy to see why with visibility at
or below 2 miles as of 04.18z. Although presently not expecting
visibility that low, have added in some mention of smoke to the
weather girds. Those who are sensitive to the smoke should keep
an eye on the forecast, and be prepared to take precautions/limit
time outdoors. Highs tomorrow in the 70s to near 80. Rainfall
amounts through Thursday are expected to remain light, with
deterministic guidance generally below a quarter of an inch.

Wildfire smoke aloft and at the surface push south of the area
Thursday night. Lows fall into the mid 40s to lower 50s with
clearing skies and light winds.

FRIDAY-SATURDAY: Trough axis deepens across MN into early Friday.
This places us in northwesterly flow and CAA into the first half of
the weekend, leading to below average temperatures. Additionally,
cyclonic flow on Friday afternoon could lead to some isolated
showers east of I-29. Model runs today show a bit more of an
unstable layer than what was noted yesterday; however, we`ll still
likely struggle with dry subcloud layer, so increased cloud cover
and virga may be the end result. Rainfall amounts on Friday would
be light, with ensemble guidance currently showing less than a
20% chance of measurable precipitation. Saturday looks dry with
the trough further off to the east. Highs in the upper 60s to
mid 70s with lows in the 40s to mid 50s. Winds during the
afternoon and evening hours may gust to around 20 mph, and expect
lots sunshine.

SUNDAY ONWARD: Ridging begins to build across the western CONUS into
the early part of next week, with northwesterly flow aloft in place
through Monday. Relatively warmer weather returns as southerly
surface flow develops into mid next week, with highs in the 80s to
near 90 possible once again. Models show a short wave moving across
the northern and central Plains early next week, but after that show
dramatically different synoptic patterns for the middle part of next
week. No changes to the NBM at this time, which keeps our forecast
warm and dry for this time frame.

&&

.AVIATION /06Z TAFS THROUGH 06Z FRIDAY/...
Issued at 1015 PM CDT Wed Sep 4 2024

A few scattered showers and thunderstorms will move northeast
through the Tri-State area into Thursday morning. Ceilings in
most areas will be VFR, but some patchy MVFR ceilings may be
possible near Highway 14.

A front ahead of this rain will move through NW Iowa into early
Thursday, turning winds to the north in the entire region.

Also behind this front will be a period of smoke that has
migrated to the surface over the past day. Some MVFR visibility
has been reported upstream, and HRRR smoke model projections
continue to push a narrow corridor of smoke through the region
during the day Thursday.

Otherwise, will need to watch a secondary area of high based
showers that could reach HIghway 14 and then Interstate 90 in
the afternoon. Confidence too low to include in this TAF
issuance.

&&

.FSD WATCHES/WARNINGS/ADVISORIES...
SD...None.
MN...None.
IA...None.
NE...None.

&&

$$

DISCUSSION...SG
AVIATION...Dux




Area Forecast Discussion...Updated

National Weather Service Lincoln IL

 906 PM CDT Wed Sep 4 2024

.KEY MESSAGES...

- Much of the next week will be dry across central IL. A few
  showers will accompany a cold frontal passage Thursday night.

- Thursday will be warm and humid, but a much colder airmass will
  begin to move in Friday and persist through the weekend.

&&

.UPDATE...
Issued at 855 PM CDT Wed Sep 4 2024

Forecast generally on track tonight into Thu morning and just a
few minor updates done like for sky conditions. Patches of cumulus
clouds have drifted northward and as far nw as a Petersburg to
Chenoa line while southeast IL has nearly clear skies as scattered
cumulus clouds dissipate at sundown. Weak southerly 15-20 kt 850
mb jet over IL has advected in deeper moisture into central IL
with PW values rising to 1-1.5 inches from I-72 south, highest in
southeast/southern IL. ILX PW value up to 0.91 inches at 00Z from
0.49 inch at 12Z Wed flight. Surface dewpoints range from around
60F from the IL river valley nw to the upper 60s and lower 70s
from Taylorville to Decatur to Terre Haute south. Forecast
challenge overnight is how much fog will develop with higher
dewpoints, light winds and mostly clear skies. The NAM and ARW
appear too aggressive with fog development and even dense fog,
while HRRR, GFS, FV3 and RAP13 show little if any fog development
late tonight/early Thu morning. With dry ground over CWA leaning
toward the HRRR fog forecast which is mainly along the river
valley like the lower IL river valley and in southeast IL. Lows in
the mid 60s from I-55 southeast and around 60F nw of the IL river
where dewpoints are 5-10 degrees lower than southeast IL.

Latest CAMS shows a cold front over central MN into southeast SD
and central Nebraska tracking se into nw IL by sunset Thursday.
Its scattered convection mostly behind/nw of the cold front, so
much of CWA should stay dry during the daytime hours Thursday and
very warm highs in the mid to upper 80s (Lawrenceville back near
90F) and dewpoints in the mid to upper 60s.

07

&&

.DISCUSSION...
Issued at 212 PM CDT Wed Sep 4 2024

High pressure off the New England coast was still ridging back
west through the southern Great Lakes and into northern IL. South
of the ridge axis, light southeast winds were beginning to advect
higher dewpoints north, reaching the low-mid 60s over southern IL
as far north as I-70. On the leading edge of this airmass, a few
showers and storms had formed over southern IL this morning in the
vicinity of a weak shortwave. As this region lifts northeast a few
showers could form (20% chance) south of I-70 through late
afternoon.

Tonight, light to calm winds, clear skies, and low dewpoint
depressions will make areas of fog a good possibility. HREF
guidance shows 20-40% probabilities of visibility reductions below
1 mile, with the highest probabilities west of I-55. Otherwise,
higher dewpoints will lead to warmer lows in the low/mid 60s.

Thursday, southwest winds increase up to 10-15 mph, advecting a
seasonably warm/moist airmass into the region ahead of a
southeastward moving cold front. With highs in the mid to upper
80s and upper 60s dewpoints, heat indices will peak in the lower
90s.

Guidance has continued to come into better agreement with a
faster cold frontal passage Thursday night and clearing the CWA
Friday morning. Due to unfavorable diurnal timing and much of the
lift going into saturation behind the front, PoPs and QPF have
continued to trend down, with around 20-30% coverage and under a
tenth of an inch of QPF. Due to the progressive nature of the
front, cold advection looks to begin in earnest on Friday when
north/northwest winds gust 15-25 mph. Should see a good gradient
in max temps from NW to SE as the colder airmass filters in from
the mid 702024s to lower 80s.

This weekend, upper level low pressure cuts off over the northern
Great Lakes and deepens causing deep layer amplified northwest
flow across our part of the Midwest. This results in a breezy and
cool weekend. Even though steep low level lapse rates will be in
place forecast soundings suggest the airmass will be too dry to
support showers.

Early next week upper ridging begins to expand east from the
Plains. This will bring gradually rising heights and warmer
temperatures. Global ensemble guidance is in good agreement that
a warm and dry pattern locks in through mid/late week.

25

&&

.AVIATION...  (For the 00z TAFs through 00z Thursday Evening)
Issued at 655 PM CDT Wed Sep 4 2024

VFR conditions are generally expected to prevail across the
central IL airports next 24 hours through 00Z/7 pm Thu, aside for
possible patchy fog with MVFR vsbys possible especially along
I-72 from 09-14Z. 1031 mb high pressure off New England coast and
ridging sw into IL/MO will still be ridging over the Ohio river
valley Thu afternoon, as a cold front entering the Dakotas this
evening tracks into nw IL by sunset Thu. Its isolated to scattered
convection to stay nw of the central IL airports through sunset
Thu, while scattered diurnal cumulus clouds with bases of 3.5-5
kft to occur early this evening along I-72 and redevelop across
the area by midday Thu. Light east to SE winds at 3-6 kts tonight
to veer SW and increase to 7-11 kts after 15Z Thu.

07

&&

.ILX WATCHES/WARNINGS/ADVISORIES...
None.

&&

$$




Area Forecast Discussion

National Weather Service Marquette MI

 732 PM EDT Wed Sep 4 2024

.KEY MESSAGES...

- High risk of rip currents continues into the evening for the
  Lake Michigan beaches of Schoolcraft County.

- Showers and a few embedded thunderstorms arrive in western
  Upper MI between 4 AM and 8 AM EDT Thursday.

- Rain chances return Thursday along a cold front with cool temperatures
  and lake effect rain chances following through the weekend.

&&

.SHORT TERM /THROUGH TONIGHT/...
Issued at 321 PM EDT Wed Sep 4 2024

Water vapor imagery and RAP analysis show the beginning of mid-level
trof amplification from central Canada into the n central U.S. in
response to a ridge building along the W Coast of N America. Low
amplitude ridging is over the Great Lakes, providing one more nice
early Sept aftn across Upper MI. Other than some high clouds over
western Upper MI, it`s been a sunny day. A layer of wildfire smoke
aloft, less dense than yesterday, is noted over the area. Temps
currently range thru the 70s F with dwpts again on the comfortable
side, mostly in the 50-55F range, though readings are around 60F
near Lake MI under southerly winds. Winds are gusting into the 20-
25mph ranges at times. These southerly winds up Lake MI and the
resulting wave action will result in dangerous swimming
conditions/high risk of rip currents thru this evening for the Lake
MI beaches of Schoolcraft County.

Amplifying mid-level trof to the w will send a cold front se,
reaching western Lake Superior late tonight/early Thu morning. As
usually verifies better, leaned toward the slower model solutions
for timing pcpn, and in this case, the vast majority of the 12z
deterministic models are well agreed on that timing. Hourly RAP/HRRR
runs since 12z also support the majority slower solution from the
12z models. So, fcst reflects shra mention reaching at IWD at 08z,
spreading e to about a Big Bay to Crystal Falls line at 12z. No
SBCAPE is avbl, but there is instability for non sfc-based parcels,
though diminishing with time. Not expecting much more than a few
rumbles of thunder embedded within what should be a largely solid
band of showers progressing into western Upper MI 08z-12z.
Temps will fall back to mostly the mid 50s to lwr 60s F tonight.

&&

.LONG TERM /THURSDAY THROUGH WEDNESDAY/...
Issued at 346 PM EDT Wed Sep 4 2024

The warming trend ends Thursday as a cold front moves across the
area from west to east throughout the day, bringing rain showers and
a few thunderstorms to Upper Michigan. While we do see bulk shear
increasing throughout the day, we actually see CAPE decreasing along
the cold front. Therefore, no severe weather is expected with any of
the convection. As for rainfall amounts, around 0.20 to 0.50 inches
is expected along the front; outside of some moderate to locally-
heavy rainfall in the strongest cells along the front, expect mostly
light rain. Expect breezy northerly winds to pick-up behind the
front Thursday into Thursday night as strong cold air advection
drops across our area. The breezy winds, in addition to the cloud
cover, could keep low temperatures from falling below 40 degrees in
the interior areas Thursday night. In addition, with the cold air
advection dropping the 850 mb temperatures to sub 4 C, expect lake-
effect rain showers to develop over the north wind belts during the
overnight hours. While the rainfall is expected to be light, some
spots may see up to several hundreths of an inch (less than a
tenth). With cold air advection expected to continue across the area
into Saturday, the lake-effect precipitation looks to continue too,
although high pressure ridging building to our north and west may
end the lake-effect rain showers by late Friday over the west half.
a closed low looks to form just east of Georgian Bay as high
pressure ridging builds to our north and west this weekend. As the
closed low spins near Georgian Bay this weekend, we could see one
more shortwave rotate around the parent low and bring some lake-
enhanced rain showers to the eastern half late Saturday through
Sunday. With the colder air associated with the cold front and later
the low pressure over us late this week through this weekend, expect
high and low temperatures well below average; expect highs Friday
and Saturday to be limited to the 50s, and lows Thursday through
Saturday nights in the 40s (possibly the 30s in the interior west).
In addition, should there be enough clearing, we may see some patchy
frost develop over the the cold spots of the interior west early
Saturday morning and again early Sunday morning.

As the low pulls away early next week, the lake-effect rainfall ends
with it. Once the lake-effect rainfall ends, expect a warming trend
and drier weather, with temperatures returning to near normal by
around next Monday. High pressure ridging over the Ohio Valley and
the Great Lakes basin should keep us precip-free to the end of next
week.

&&

.AVIATION /00Z TAFS THROUGH 00Z FRIDAY/...
Issued at 732 PM EDT Wed Sep 4 2024

Dry and VFR conditions this evening will deteriorate late
tonight/early Thursday morning as a cold front approaches from the
west, then moves through Upper Michigan Thursday. Ahead of the
front, low level wind shear should be expected at KIWD/KCMX.
Showers, perhaps mixed with some elevated thunderstorms initially at
KIWD, will move into western Upper Michigan late tonight/early
Thursday morning, then KSAW Thursday. Precip timing among recent
hourly models have slowed some and its possible timing may be
delayed further in future TAF issuances. Ceilings should fall to low
MVFR and IFR with the showers. Post frontal airmass will be cool,
with some lake effect rain showers before drying late in the TAF
period.

&&

.MARINE...
Issued at 346 PM EDT Wed Sep 4 2024

Southwest to southerly winds of 20 to 25 knots continue over the
western and eastern lake this afternoon and evening ahead of an
incoming cold front dropping down from northwestern Ontario tonight
through Thursday. Behind the cold front, expect the winds to veer
north to 20 to 30 knots. With strong cold air advection continuing
behind the front Thursday, expect the stronger northerly winds to
continue across the lake through Friday night. As high pressure
ridging builds north and west of the Upper Great Lakes this weekend,
a closed low forms east of Georgian Bay. As a shortwave rotates
around the parent low back towards us Saturday into Sunday, expect
the northerly 20 to 30 knot winds to become northwesterly over the
east half of Lake Superior Saturday evening into Sunday. As the
parent low leaves for northern Quebec and high pressure ridging
moves overhead, expect the winds to weaken to 20 knots or less and
to remain that way through next week as high pressure ridging
dominates the Great Lakes basin.

Some thunderstorms are possible along the cold front late tonight
through Thursday as the front passes over Lake Superior from the
northwest to southeast. While not expected, there is a small (5%)
chance that some severe hail and wind could be seen in the western
lake late tonight along the front. Therefore, vessels traveling
tonight need to be extra-vigilant and be weather-aware, as chaotic
seas from high winds and large, damaging hail could make an
appearance.

&&

.MQT WATCHES/WARNINGS/ADVISORIES...
Upper Michigan...
  Beach Hazards Statement until 9 PM EDT this evening for MIZ014.

Lake Superior...
None.
Lake Michigan...
None.

&&

$$

SHORT TERM...Rolfson
LONG TERM...TAP
AVIATION...JTP
MARINE...TAP




Area Forecast Discussion

National Weather Service Springfield MO

 655 PM CDT Wed Sep 4 2024

.KEY MESSAGES...

- Patchy fog will be present in some areas east of Highway 65
  late tonight into Thursday morning, especially in river
  valleys and low-lying areas.

- There is a 10-20% chance of showers and thunderstorms
  Thursday night into Friday with frontal passage. Most areas
  remain dry.

- Dry conditions and below average temperatures are expected for
  the weekend.

&&

.SHORT TERM /THROUGH THURSDAY/...
Issued at 230 PM CDT Wed Sep 4 2024

Several weak shortwaves are noted on current water vapor
imagery amid weak upper-level flow. The most potent shortwave is
currently progressing across the northern CONUS Rockies. A
second, more subtle, shortwave is moving across OK and into AR.
A plume of intense southwest CONUS dry air aloft--as noted by
our 12Z sounding and current water vapor imagery--is keeping
this shortwave from producing any precipitation in our area. At
the surface, broad high pressure is situated across the eastern
CONUS, creating clear skies, calm winds, and cooler air across
our region. As such, highs today are on track to reach the
mid-80s.


Patchy fog east of Highway 65 tonight into Thursday morning:

The clear skies, calm winds, and cooler air will be prime
conditions for fog development. The main uncertainty is moisture
availability. A gradient of moisture will be present across our
area. Out towards Joplin, dewpoints will be in the lower to
middle 50s while our towards West Plains, dewpoints will be in
the mid-60s. With lows dropping to around 60, the best chance
for patchy fog will be out in the eastern Ozarks, east of
Highway 65. HREF gives a 40-60% chance for fog in these areas.
Given crossover temps not being terribly impressive, and there
not being 100% agreement among models, fog likely will not be
very dense. The most dense areas will be in valleys and low-
lying areas, but mainly expect patchy areas of visibilities
below 3 miles, and below 1 mile in localized areas.


Low chance and low confidence for showers Thursday afternoon:

Weak SSE`ly winds will allow for some modest moisture return
ahead of the approaching front. Highs will reach the middle to
upper 80s with dewpoints in the mid-60s. Latest RAP runs suggest
the potential for a narrow corridor of 250-750 J/kg MLCAPE,
generally along a line from Branson to Rolla. This may be enough
for a few isolated showers within this region. However, copious
amounts of dry air aloft and weak forcing should keep anything
from developing. Therefore, PoPs are below 15% at this time, but
if confidence increases, don`t be surprised to see some low
15-20% PoPs for this area Thursday afternoon.

&&

.LONG TERM /THURSDAY NIGHT THROUGH WEDNESDAY/...
Issued at 230 PM CDT Wed Sep 4 2024

10-20% chance for showers and thunderstorms Thursday night:

A big ol` bowling ball mid- and upper-level low will drop into
the Great Lakes region from central Canada Thursday into Friday.
Along with the trough/low, a strong cold front will dive south
through the region. With such a strong passage, lift will be
abundant, and showers and thunderstorms will certainly be
possible. However, chances are low (10-20%) as upper-level flow
will be weaker across our region, and surface deformation flow
will also be situated across the region. Additionally, moisture
will be rather sparse, and strong capping could inhibit
widespread precipitation. Nevertheless, some isolated to
scattered showers and thunderstorms will be possible as the
front moves through late Thursday night through the day Friday
(10-20% chance). With weaker flow aloft and marginal
instability, no severe weather is expected with any storms.


Dry conditions and below average temperatures for the weekend:

The upper-level low will stall over the NE for the latter half
of the weak. With the edges of it setting up over our region,
and the cold front dropping well south of our area, a nice shot
of cooler than normal air will take hold through the weekend.
Highs Friday will be in the upper 70s to middle 80s and drop
into the 70s for the weekend with temperatures below 70 toward
central Missouri. Lows Thursday night will be in the middle 60s
and drop to the 50s over the weekend with areas in the eastern
Ozarks seeing temperatures as low as the middle 40s. This is
much cooler than average temperatures for early September with
the Extreme Forecast Index at 0.84 for the eastern Ozarks.
Indeed, the forecast low for Vichy is 47 F Saturday night and
the record low is 45 F. Given some likely bias correction in the
NBM, forecast lows could trend lower. Current probs to break
this record are at ~20%.

Into early next week, the upper-level low will exit the CONUS
and ridging will once again build into the area from the west.
This will allow temperatures to slowly warm back up into the 80s
as highs Monday and Tuesday with lows in the 50s. Given strong
surface high pressure still within the region, and no shortwaves
forecast to move through, chances for precipitation are very low
throughout the long term period.

In the extended range (8-14 days; mid-September) the CPC has a
40-50% chance for below normal precipitation. With the ridge
expected to continue to slowly shift eastward, warm temperatures
should continue to build into the region during this timeframe,
giving us a 60-70% chance for above normal temperatures.

&&

.AVIATION /00Z TAFS THROUGH 00Z FRIDAY/...
Issued at 634 PM CDT Wed Sep 4 2024

The weather pattern will favor light and variable winds clear
skies and VFR flight conditions tonight and through much of the
day Thursday for KSGF and KJLN. Some cumulus may spread into
the region Thursday afternoon though conditions should remain
VFR.

With overnight temperatures cooling to near the dew point
temperatures in the vicinity of the KBBG terminal, patchy fog
may develop. Limited coverage and expected impacts are expected
with a period of MVFR visibilities around sunrise. Otherwise no
impacts are expected.

&&

.SGF WATCHES/WARNINGS/ADVISORIES...
KS...None.
MO...None.

&&

$$

SHORT TERM...Price
LONG TERM...Price
AVIATION...Hatch




Area Forecast Discussion

National Weather Service Shreveport LA

 Issued by National Weather Service Fort Worth TX
1004 PM CDT Wed Sep 4 2024

...New UPDATE, AVIATION...

.UPDATE...
Issued at 958 PM CDT Wed Sep 4 2024

Current forecast remains in decent shape with an area of light to
moderate showers currently spreading across northwest Louisiana
late this evening. Scattered showers will continue through the
overnight and into Thursday, especially south of I-20.

&&

.SHORT TERM...
(This evening through Thursday Night)
Issued at 210 PM CDT Wed Sep 4 2024

2pm temps are quite varied from 79 at several NE TX sites, and
mostly a range of 80s for AR/LA with 90 at Monroe the hot spot
about to be cooled off. The tropical surge with the easterly wave
continues to elevate dew points through lower and some mid 70s
from Natchitoches to Monroe. This gradient is sporting most of the
TCU developing convection so far with thunder knocking on the
door over in Richland Parish. Passing middeck showers continue for
now over our I-30 corridor with low to mid 60 dew points there.

The HRRR shows much of that diminishing with remaining heating,
while the band approaching is reinforced with a push spiraling in
from Houston to Alexandria in the coming peak of heating as the
upper level weakness resides over the TX/LA coastal region. Much
of this activity is brought to us by the upper low and the old
stationary frontal boundary along I-10 with SW flow aloft pulling
anvils eastward. Heating then in the Parishes will continue to
fortify the convection piling into our I-49 corridor this evening.
Coverage and intensity will fade with sunset, but the HRRR
continues with light QPF over AR/LA into the overnight.

The cool front is on approach dropping out of the Dakotas right
now will arrive early in our long term. Otherwise little change
over the next day or two with muggy warm 80s for highs on Thursday
and lows again tomorrow night hanging in the lower 70s for an
average, but some upper 60s in our far N Counties in OK/AR. The
SPC continues a general risk for us with WPC looking at 1 to 2
inches mainly in LA along and S of I-20. Our coverage of showers
and thunderstorms will keep high chances going in the soup with
less amounts in NE TX, even ahead of the front. /24/

&&

.LONG TERM...
(Friday through next Tuesday)
Issued at 210 PM CDT Wed Sep 4 2024

The afore mentioned cold front will bring a taste of fall with
drier dew points spreading southward during Friday afternoon on NE
winds 5 to 10 increasing to 10-20 into late evening and all day
Saturday. So we are still looking at medium range progs keeping
mid to upper 80s for highs in the long term, but our lows will
make the greatest strides toward the first fall feel. The front
may scour up a few more showers or an isolated thunderstorm across
our I-30 corridor late day with most of this still lingering
coverage over S AR, LA and deep E TX. NE TX will see continued
drought building with only trace to tenth of an inch amounts at
best because the easterlies wave just become stationary along
I-49, keeping the richer pwats out of the Lone Star State. Once
the high pressure spreads in on the gusty NE winds, we will all be
done with rain again for a good while as the high sets up shop
over the NE U.S. and maintains a hold on Four-State area. /24/

&&

.AVIATION...

Issued at 958 PM CDT Wed Sep 4 2024

VFR generally prevails across the region but widespread low cigs
will eventually spread northward into much the region. Ongoing
showers will spread northwest across Louisiana and East Texas
through the overnight and continue for much of the day on
Thursday.

&&

.SHV WATCHES/WARNINGS/ADVISORIES...
AR...None.
LA...None.
OK...None.
TX...None.
&&

$$

SHORT TERM...99
LONG TERM....99
AVIATION...99




Area Forecast Discussion

National Weather Service Salt Lake City UT

 315 PM MDT Wed Sep 4 2024

.SYNOPSIS...A weak, dry cold front will continue to cross the area
ushering in higher concentrations of smoke for northern Utah.
Smoke concentrations will gradually decrease by Thursday. A
warming and drying trend is expected through the weekend, with a
gradual increase from south to north in coverage of high elevation
thunderstorms.

&&

.SHORT TERM (Through 12Z/6AM Friday)...As of early Wednesday
afternoon, a positively-tiled trough axis was located over
Wyoming extending southwestward into NE Utah, while a ridge of
high pressure was building across Southern California. In the wake
of the trough, deep-layer NW flow had allowed for smoke from
Idaho wildfires to infiltrate northern Utah and SW Wyoming, and
both the concentration and timing was more robust than what was
indicated by the HRRR smoke model, as a few air quality sensors
jumped into the `unhealthy` category. This model suggests smoke
will gradually slide westward overnight, with the highest
concentrations sliding largely west of I-15. HRRR smoke model
advertises further smoke dispersion on Thursday, with
concentrations forecast to become light. Given how much
concentrations overachieved today, confidence has dwindled
somewhat as to whether smoke will diminish as much as advertised
on Thursday.

Just enough moisture, instability and wind shear remains to
support isolated showers and thunderstorms across the far eastern
reaches of the Uintas through sunset, with a strong thunderstorm
possible until then. With ingredients to support organized
convection quickly dwindling, the window for organized convection
here is closing quickly.

Development of modest easterly pressure and thermal gradient
overnight will lead to some enhanced easterly canyon winds from
the typical locations across the Cache, and across the Northern
Wasatch Front and Wasatch Front from Tremonton to Parleys canyon.
HREF max gusts are shown in the 35-45 mph range for the most wind
prone locations such as Park Lane in Farmington, with the
strongest gusts forecast between midnight and 9AM Thursday
morning. This may help to locally diminish smoke concentrations
somewhat. Otherwise, a ridge of high pressure builds across the
region into at least the weekend, bringing a return to summerlike
temperatures to the region.

.LONG TERM (After 12Z Friday), Issued 343 AM MDT...
An upper-level ridge will be situated overhead at the start of
the long-term period on Friday morning, resulting in at least one
more day of sunny skies. As this ridge shifts slightly eastward
heading into the weekend, moisture will begin to filter in from
the south. Model guidance has trended later in terms of timing of
this moisture surge, with only isolated showers and thunderstorms
possible Saturday afternoon across higher terrain of southern
Utah. Precipitation chances will expand across much of Utah and
southwest Wyoming on Sunday. PWATs will remain elevated through
Monday, though dry low levels will likely promote more of a dry
microburst threat rather than flash flooding.

As mid-level flow shifts ever so slightly to southwesterly on
Tuesday, drier air is likely to filter back into the area,
limiting precipitation chances to higher terrain, particularly
across northern areas. By mid-week, uncertainty in the forecast
increases along with the development of a northeastern Pacific
trough. There is still plenty of uncertainty with timing and
amplitude of this system, though deterministic models suggest the
trough comes ashore sometime in the second half of the work week
in some shape or form.

&&

.AVIATION...KSLC...Drier conditions settling in behind departing
system, but deep layer wind direction now supporting advection of
smoke across much of the region. Anticipate modest periodic VIS
reductions to around 4SM to 6SM accordingly through the day, with
guidance suggesting decreasing concentrations of smoke overnight
into Thursday. Otherwise, anticipate low level winds to follow a
fairly typical diurnal directional pattern.

.REST OF UTAH AND SOUTHWEST WYOMING...Quieter and drier conditions
across much of the region as system departs, but deep layer winds
now helping to advect smoke across many northern terminals. Through
the day, anticipate potential periods of VIS reductions to around
4SM to 6SM or so accordingly. Model guidance then suggests smoke
concentrations should begin to decrease overnight into Thursday.
Winds at area terminals are largely anticipated to follow a fairly
diurnally typical directional pattern. One noted exception is the
potential for marginally enhanced easterly canyon winds overnight at
any terminal near enough to prone areas near northern Utah`s high
terrain.

&&

.FIRE WEATHER...Northwesterly flow behind a departing trough has
allowed for smoke from Idaho wildfires to drift into northern
Utah, with moderate smoke concentrations observed at times early
Wednesday afternoon. This smoke will linger into Thursday, but
will begin to thin out. Meanwhile, a ridge of high pressure will
gradually begin to build into the Great Basin on Thursday,
lingering into at least early next week. This will bring a gradual
warming and drying trend to the region, with summerlike
temperatures returning this weekend and persisting into early next
week as temperatures climb to 5F to 15F above normal for early
September. We do see some potential for a weak trough to skirt
through Nevada on Sunday, bringing some locally breezy winds to NW
Utah Sunday afternoon, however it appears winds will remain below
critical fire weather thresholds. As we get into early next week,
a strong area of low pressure will move into the western United
States, strengthening southwest winds across our region, and
allowing for some moisture to return. While an isolated shower or
thunderstorm will be possible across southern Utah high terrain as
early as Saturday, more widespread high-based activity is
expected to hold off until Sunday. At least isolated showers and
thunderstorms may linger into early next week, although
thunderstorm coverage and intensity into next week is highly
uncertain at this time.

There is quite a bit of uncertainty with regards to how this
trough evolves, with two scenarios unfolding by the middle of next
week. One scenario is brings a strong low near the area, with
an associated strong cold front moving through Utah sometime by
the middle of next week, while another scenario suggests a grazing
trough to our north with an associated weak front with little to
no cooling. We`ll continue to monitor these trends as certainty
increases as to which direction the forecast will take next week.

&&

.SLC WATCHES/WARNINGS/ADVISORIES...
UT...None.
WY...None.

&&

$$

ADeSmet/Warthen/Cunningham

For more information from NOAA`s National Weather Service visit...
http://weather.gov/saltlakecity