Forecast Discussions mentioning any of
"HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 10/30/24
Area Forecast Discussion
National Weather Service La Crosse WI
1001 PM CDT Tue Oct 29 2024
.KEY MESSAGES...
- Warm and windy conditions continue, with a Wind Advisory
remaining in effect for portions of northeast Iowa and
southwest Wisconsin through the evening.
- Showers and storms increase across the area Wednesday into Wednesday
night. Storms may bring periods of heavy rainfall and a few
storms could be strong to severe.
- Windy and cooler temperatures Thursday with diminishing
precipitation chances. Friday, lighter winds and high
temperatures in the 40s to middle 50s.
&&
.UPDATE...
Issued at 955 PM CDT Tue Oct 29 2024
Weather will be on the upswing over the next 24 hours as the
deep trough energy over the western CONUS ejects northeast right
over the area. The latest radar wind profiles are showing a
strong low-level wind field just above the surface with KARX 40
kts at 500m, 50 kts at 1500m. Just a very slight inversion near
the surface has allowed some decoupling with a thin boundary
layer so winds are generally 15G30 mph at most across the area.
This wind field remains overhead through the night and with very
mild low temperatures in the upper 60s for most, only a few
degrees of warming after sunrise will allow access toward the
40-45kt wind field Wednesday morning. We could see some gusts to
40 mph in the 8-11 am time frame.
Also of note is a bit of elevated instability in far southwest
WI and northern IL with some moisture advection, might see some
popcorn showers down there in the morning. Have not added a
rain chance there, but the RAP is generating a bit of light
rainfall. Confidence isnt very high, the latest HRRR runs have
some dots of echo, all south of the forecast area. Will monitor
this overnight.
Otherwise, current messaging still has the strong thunderstorm
chance in the afternoon south and east of La Crosse, similar to
the heaviest rain area. This is leaning into the CAM outputs and
HREF guidance versus the global ensembles that are non-
convective allowing. This seems all on track at this point.
Will have to keep a close watch on the convective instability
Wed afternoon, the shear profile is impressive
As the low shifts east on Thursday and cold air sweeps in, will
have to monitor forecasts to ensure snow isnt in play in our
most northwest counties in the deformation comma that is hanging
back to our northwest.
&&
.DISCUSSION...
Issued at 240 PM CDT Tue Oct 29 2024
Tonight - Wednesday: Warm/Windy & Heavy Rain/Storm Potential
A warm day today as expected, with the record high temperature
already (before 2 PM) tied at KLSE and within a degree or two of the
record at KRST. Winds have increased across the area and the Wind
Advisory remains in effect through the evening for portions of
northeast Iowa and southwest Wisconsin. A strong low level jet
develops tonight ahead of an approaching cold front. However, with
lower confidence in the degree of mixing through the overnight, have
opted to not continue the advisory into the overnight hours at this
time. Otherwise, temperatures overnight tonight are only forecast to
drop into the 60s.
An upper level trough will move eastward towards the southern High
Plains Wednesday. In addition, a wave of low pressure moving along a
front is forecast to move northeastward towards the region. The
current forecast suggests another warm and windy day ahead of
the front, with high temperatures still reaching into the 70s.
With a moist airmass in place and strong forcing, showers and
storms are expected to develop with the front during the day on
Wednesday. There is still some variability between hi-res model
guidance on exact timing of shower and storm development. Will
note some variability in model forecast soundings on the
strength of capping through the morning hours. Even so,
consensus suggests increasing coverage in showers and storms
into the late afternoon/evening. With PWATS nearing the MAX of
climatology, moderate to heavy rainfall continues to look
possible at times. This is reflected in the 29.12 HREF 24-hr QPF
ensemble PMM which shows a general 1 to 2" across the area,
with even some suggestion of a stripe of 2.5-3+" across portions
of northeast Iowa into southwest Wisconsin.
Although weak instability continues to be a limiting factor to
storms, the strong forcing/support and increased shear values
present in the warm sector may be enough to support some strong to
severe storms. With this high shear/low CAPE set-up, SPC has
maintained a Marginal Risk (level 1 out of 5) for severe storms
across portions of the area for Wednesday, with wind based threats
looking to be the more likely hazards.
Wednesday Night into Friday
Upper level trough/surface low quickly lifts northeast into southern
Ontario Canada Thursday/Thursday night. On backside of upper level
trough/surface low...pressure gradient tightens across the area
and winds will increase from the northwest during the day
Thursday. Have increased sustained wind speeds during the day
Thursday to 15 to 20 knots and gusts to 25 to 35 knots. Winds
could be higher...based on the tightening pressure gradient and
deepening low pressure over the Great Lakes Region.
In addition...subsidence behind the upper level trough/surface low
should diminish precipitation chances from west to east across the
forecast area Thursday afternoon/evening.
Cooler temperatures will advect into the forecast area Thursday
afternoon into Friday...as the latest 29.12z NAM/GFS suggest
925mb temperatures falling to zero to minus 2 degrees celsius by
00z Friday. Temperatures Thursday afternoon will slowly fall or
remain nearly steady in the 40s and highs Friday are expected
to be in the middle 40s to middle 50s.
Friday Night into Tuesday
Main forecast concerns Friday night through Tuesday are
precipitation chances through the forecast period. Upper level
trough digs over the southwestern United States and ridging
amplifies over the eastern United States. This allows southwesterly
flow aloft to develop over the central United States. Pieces of
energy embedded in the southwesterly flow aloft will move over the
Upper Midwest/Great Lakes Region Saturday into Tuesday. With each
piece of energy...latest ensembles/deterministic models suggest
ample moisture convergence and lift over the forecast area. Showers
or rain is expected to overspread the forecast area Saturday and
continue on and off through the forecast area. Temperatures through
the forecast period will remain slightly above to near normal...as
the latest NAEFS suggest standard anomalies to be around plus 1
degree celsius through much of the forecast period. Highs should
climb into the lower 50s to lower 60s.
&&
.AVIATION /00Z TAFS THROUGH 00Z THURSDAY/...
Issued at 646 PM CDT Tue Oct 29 2024
VFR ceilings seen across the forecast area from northeast Iowa,
southeast Minnesota, and western into central Wisconsin at
30.00Z TAF issuance. Have kept increased wind gusts through the
overnight hours even though confidence is low as sites west of
the Mississippi River have decreased with gusts near 20kts.
Precipitation chances move to the northeast through the early
morning hours initially in a narrow band from Iowa through
Minnesota into Wisconsin. Exact location of this initial band
remains in question given its narrow nature. Therefore, have
added the potential for showers initially at KRST at 30.12Z. If
anything, this may need to be delayed depending on strength of
initial saturation. Rain and thunder chances increase through
the early afternoon hours. Higher thunder chances remain just
east of Rochester and therefore haven`t added TAF inclusion
there at this time. May need to be added with 30.06Z TAF
issuance for a limited timeframe. Highest thunder potential
extends from northeast Iowa through central Wisconsin. Given
the location of higher confidence, have included thunder
potential at KLSE for 30.00Z TAF issuance.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
WI...None.
MN...None.
IA...None.
&&
$$
UPDATE...Baumgardt
DISCUSSION...DTJ/EMS
AVIATION...JAR
Area Forecast Discussion
National Weather Service Cheyenne WY
902 PM MDT Tue Oct 29 2024
.UPDATE...
Issued at 852 PM MDT Tue Oct 29 2024
Forecast over the next 12 hours looks good with storm system
lifting northeast across the area tonight. Snow has been pretty
steady from Rawlins northeast to around Douglas, with little or
no snow southeast of this line. Adjusted POP and QPF slightly
with lower snowfall totals below 6000 feet. Most of the snow
that has fallen in the lower elevations continues to melt with
temperatures hovering around freezing and a relatively warm
ground.
Did add areas of fog to Laramie County and southern Platte and
Goshen counties. Visibilities as low as one quarter mile are
possible. Low confidence on duration, however, since high res
models are struggling to initialize the fog at all. Expect
periods of fog through early Wednesday morning, but not
expecting it to be continuous.
&&
.KEY MESSAGES...
- Winter weather is ongoing across much of the area. Snow and
rain showers will continue overnight and into the day
Wednesday. Winter headlines have been issued for areas
expecting accumulating snow.
- Winter Weather Advisories and Winter Storm Warnings have been
issued through noon Wednesday.
&&
.SHORT TERM /THROUGH THURSDAY/...
Issued at 314 PM MDT Tue Oct 29 2024
Radar and observations from across the CWA show fairly
widespread precipitation across portions of southeast Wyoming
and western Nebraska. With the front slowly pushing its way
across the CWA with precipitation following behind it, some
areas have already transitioned from rain to snow. The earlier
transition time lead to the issuance of a Winter Weather
Advisory this morning for the Arlington and Elk Mountain area as
well as Shirley Basin. Webcams from those areas indicated that
snow was at least beginning to stick to grassy and elevated
surfaces. Roads will likely follow sometime in the afternoon as
precipitation continues and temperatures further cool. Also
moved up the start time of the Winter Storm Warning in Converse
County as snow was beginning to stick. Rain and snow will
continue overnight, although precipitation will become less
widespread as the overnight progresses.
Overall the forecast remains on track. Slight changes in some models
have lead to an increase in strength of the storm. The GFS does
develop a broad upper-level closed low over Wyoming Wednesday
evening. It also shows a better TROWAL than what previous runs were
showing. This does increase snowfall totals across portions of the
CWA where headlines are luckily already in effect. Hi-Res guidance
like the HRRR and NamNEST also show this increase in snowfall. Once
the surface low tracks a bit further into northeast Colorado, the
northern and western parts of the CWA will get into great wrap
around moisture. A prolonged period of northerly winds is expected
overnight. This northerly flow puts areas like the North Laramie
Range, Ferris/Seminoe/Shirley Mountains and the Pine Ridge in
upslope flow. These north facing slopes will do excellent in upslope
flow with orographic lift providing the mechanism for high snowfall
totals. Lower elevation areas north of these ranges will also
benefit from upslope flow increasing snowfall totals. Douglas, in
particular, has the potential to see 8+ inches of snow with this
storm! The aforementioned areas are in a Winter Storm Warning and
will see the highest totals with this system. Areas out west are in
Winter Weather Advisories. These areas will benefit from wrap around
moisture overnight, but won`t necessarily benefit from any strong
forcing. Totals in these areas will range from 2 to 6 inches. Areas
in Nebraska and along much of the Interstate 80 corridor will not
benefit from the ample moisture. Some showers will be possible this
evening, but much of the night will stay dry due to drier air aloft.
Lingering wrap around moisture on Wednesday and continued northerly
flow across much of the area will cause showers to persist
throughout the day. Showers will taper off from west to east, with
the last of the showers dissipating in the Nebraska panhandle
Wednesday evening. Some additional snowfall accumulations will be
possible on Wednesday, especially in areas of upslope flow and the
high terrain.
With high pressure building in western Wyoming post trough, and a
surface trough east of the Laramie Range, MSLP gradients west of the
Laramie Range will tighten Wednesday night. CAG-CPR 700 mb height
will also respond to elevated values around 40 meters. 700 mb winds
will max out around 50 kts with good subsidence. Given the current
variables, elevated to high winds will be possible. In-house
guidance is picking up on high wind potential for Arlington/ELk
Mountain, however did decide to hold off on issuing any high
wind products at this time. Would like to see some stronger
forcing for this event before issuing anything. Winds will
likely still be elevated late Wednesday night into Thursday
morning with gusts over 50 MPH possible. Strong gusts will also
be possible in the South Laramie Range and Bordeaux.
Aside from a breezy day, Thursday will be a quieter day after the
system is fully passed. Temperatures will warm up to about
average by late October standards. This means highs in the 40s
out west and low to mid 50s east of the Laramie Range. Those who
are out trick or treating on Halloween evening can expect
lighter winds but chillier temperatures in the 30s and 40s.
&&
.LONG TERM /THURSDAY NIGHT THROUGH TUESDAY/...
Issued at 314 PM MDT Tue Oct 29 2024
Mild weather will carry us through most of the weekend, but
attention then turns to a few potential storm systems moving through
the area next week.
A fairly active synoptic weather pattern will continue through the
long term forecast period, a significant change from nearly 2-months
straight of dominant ridging. We`ll be in between storm systems
through at least Saturday as today`s system clears out well to the
east. Another potent longwave trough will be slowly moving across
the NW CONUS Thursday through Saturday with a series of shortwaves
circling around it. On Friday, ridging will try to build back in
over the central and eastern CONUS, pushing temperatures back to
above normal values for this time of year. However, recent model
guidance has shifted slightly southward with a subtle vort-max
ejecting out of the longwave trough across Wyoming on Friday, which
will slightly delay the warm-up. As a result, brought forecast highs
down just a smidge for Friday, though highs should still be near to
about 5F above normal for the High Plains. The trough strengthening
on Saturday will also amplify the downstream ridge which should lead
to decent warm air advection over the area Saturday. While 700-mb
temperatures peak on Saturday ranging from 0 to +5C across the area
in the multi-model mean, increasing cloud cover and the lack of
downslope winds may prevent temperatures from getting quite as high
as those values aloft could support. Still, it looks perhaps a few
degrees warmer than Friday.
Model guidance is still divided in handling the next system Sunday
into early next week. The main discrepancy remains the treatment of
a secondary shortwave diving around the longwave trough over the
weekend, specifically how strong it will be and how far south it
drops. Possible scenarios range from a progressive open wave to a
potent closed low as far south as southern California, with most
somewhere in between. Cluster analysis reveals 3 main groupings into
which most ensembles fall. The first cluster, representing about 40%
of members, is the open wave solution. In this scenario, the cool
down occurs faster (on Sunday), and most of the area has a chance
for some light precipitation in the range of a trace up to 0.1 to
0.2 or so in the more favored areas. The second cluster, also
represented by about 40% of members, is the middle ground solution.
This one has a strong upper level low partially closing off over the
Great Basin or Four Corners area. While the cool down would occur
slightly later with this scenario, it would be the best chance for
appreciable precipitation. QPF means among these members range from
about 0.1 to 0.5" across the forecast area. The last scenario,
including about 20% of members, is the southernmost solution. In
this case, the closed low dives well to the south towards southern
California. The parent trough then moves through quickly as a short-
lived and mostly dry cold snap with fairly low chances for
appreciable precipitation across our area. The deterministic ECMWF
falls into that grouping also. With little insight into which
scenario will be favored at this time, the current official forecast
represents a blend of each.
&&
.AVIATION /00Z TAFS THROUGH 00Z THURSDAY/...
Issued at 549 PM MDT Tue Oct 29 2024
A trough aloft will move slowly across the region tonight and
move to the east of the area on Wednesday.
Wyoming TAFS...For Rawlins and Cheyenne, ceilings will be under
1000 feet until 16Z, with periods of snow and fog reducing
visibilities from 3/4 to 4 miles, then ceilings will improve to
3500 feet after 16Z.
For Laramie, ceilings will be near 6000 feet with occasional
visibilities near 3 miles in snow and fog from 09Z to 18Z, then
ceilings will lower to 1500 feet from 14Z to 18Z, and improve to
5000 feet after 18Z.
Nebraska TAFS...For Chadron and Alliance, ceilings will lower
under 1000 feet this evening with occasional visibilities from
3 to 5 miles in rain and fog, then ceilings will improve to
3500 feet after 16Z.
For Scottsbluff and Sidney, ceilings will lower to 3500 to
5000 feet this evening, then to 700 to 2000 feet after 04Z,
then improve to 3500 feet after 16Z. Winds will gust to 30 knots
until 04Z.
&&
.CYS WATCHES/WARNINGS/ADVISORIES...
WY...Winter Storm Warning until noon MDT Wednesday for WYZ101-103-
104.
Winter Weather Advisory until noon MDT Wednesday for WYZ102-
105-109-110-112-114.
NE...None.
&&
$$
UPDATE...TJT
SHORT TERM...SF
LONG TERM...MN
AVIATION...RUBIN
Area Forecast Discussion
National Weather Service Dodge City KS
555 PM CDT Tue Oct 29 2024
.KEY MESSAGES...
- Marginal Risk (Level 1/5) severe storms from roughly midnight
to 7 AM early Wednesday morning, generally east of Highway
283.
- Another round of more robust severe thunderstorm risk mainly
along and east of Highway 281 (Pratt-Medicine Lodge areas)
early to mid afternoon Wednesday.
- Wet pattern ahead for much of the southern and central Great
Plains from this weekend into early-mid next week which would
include multiple rounds of showers and thunderstorms in a
slow-evolving Southwest Low setup.
&&
.DISCUSSION...
Issued at 351 PM CDT Tue Oct 29 2024
This afternoon`s water vapor loop and RAP analysis revealed quite
the deep longwave trough across the western CONUS with a couple of
embedded shortwave disturbances of note. The first of which was
lifting northeast out of eastern Utah into southern Wyoming, leading
to a large area of precipitation from northern Colorado into Wyoming
and western South Dakota. There was another shortwave trough
rounding the base of the longwave trough, and this will take a track
across the CO-NM border into western KS late tonight through
Wednesday. As the second disturbance approaches early Wednesday, a
surface cold front will be pushing south early in the day. The front
will advance fairly slowly, and when mid tropospheric cooling (500-
700mb) encroaches on the lower tropospheric warm/moist sector ahead
of the low level front, showers and thunderstorms are expected to
expand in coverage. Interestingly, there is still quite a bit of
model uncertainty in terms of when the initial shower and
thunderstorm development will occur. Global spectral models like the
ECMWF and Canadian GEM show development as early as 03-06Z time
frame tonight up along I-70 from WaKeeney to Hays while high-
resolution CAMs lean toward a much later initial development around
12-15Z Wednesday.
Official forecast will call for mainly 20-30 POPs in the 06-12Z time
frame late tonight, generally east of U283. Any storms that can
become establishes in the 06-12Z time frame will work with
increasing CAPE as overall atmospheric destabilization increases
thanks to the aforementioned mid-level cooling. The latest SPC Day
One Marginal Risk (Level 1 of 5), which is valid through 12Z
Wednesday, looks good for our eastern counties for marginal hail (1"
in diameter) and an isolated high wind risk 60+ mph gust. These
early morning storms are likely to move northeast into central
Kansas along the frontal zone, but as we head deeper into the day,
especially after 18Z, renewed development of even more robust
surface-based convection appears fairly likely across far south
central Kansas counties of Pratt and/or Barber. The NAM12 model
continues to support this, but CAMs are a bit less robust in terms
of modeled composite reflectivity and Updraft Helicity tracks (later
and farther east into NWS ICT`s forecast area). The latest SPC Day
Two outlook pushed the western edge of the Slight Risk area (Level 2
of 5) and even the Marginal Risk (Level 1) just east of Pratt-Barber
County, so SPC seems to be favoring the latest HREF Updraft Helicity
fields (a loose proxy for areal coverage/severity of modeled deep
moist convection).
Regardless of whether our southeastern counties will be involved in
severe activity or not, pretty much all models show the severe
weather risk pushing well east into central Kansas and Oklahoma
after 23Z or so (6 PM CDT). High pressure will build in quick
Wednesday Night, encompassing western Kansas during the day Thursday
with much quieter weather, especially with respect to wind!
After Tonight/Wednesday`s storm moves on, the focus will turn to the
weekend and early next week as another deep trough/Pacific jet
streak dives south-southeast across the western CONUS. More global
models and associated ensemble members are showing an impressive
Southwest Low signal, which will lead to redevelopment of a large
warm/moist sector across the southern High Plains. There is a
tremendous rain signal across West Texas from this weekend into
early next week from the Grand Ensemble, with 29/12Z run total QPF
from early this weekend through next Wednesday 6 November in the 1
to 3" range focused on West Texas northeast across much of Oklahoma
into southeastern Kansas. QPF tapers off farther northwest into our
southwest Kansas region (1/2" to 2" across the southeastern two-
thirds of our DDC CWA. This will be a slow-evolving, longwave
pattern from the weekend into early-mid next week with subsynoptic
details that simply cannot be predicted this far in advance, but
there is certainly a probabilistic shift toward above to perhaps
well-above normal precipitation for a fair portion of our southwest
Kansas region from 2 November to about 6 November.
&&
.AVIATION /00Z TAFS THROUGH 00Z THURSDAY/...
Issued at 555 PM CDT Tue Oct 29 2024
VFR is expected through much of the period. The main exception to
this is at KHYS in the morning, where some MVFR cigs associated with
shra is possible. Otherwise, a strong LLJ will continue through the
first half of the overnight period. This will lead to LLWS across
the terminals. The LLJ should shift off to the east by early morning,
with winds decreasing a bit, although still strong from S 20-30 with
gusts to 40kt to S to SW 15-20 kt. A fropa is expected tomorrow during
the day with NW to N 15-25 kt winds in its wake.
&&
.DDC WATCHES/WARNINGS/ADVISORIES...
Red Flag Warning until 7 PM CDT /6 PM MDT/ this evening for
KSZ030-043>045-061>063-074>077-084>086.
High Wind Warning until 7 PM CDT /6 PM MDT/ this evening for
KSZ061-062-074-075-084-085.
&&
$$
DISCUSSION...Umscheid
AVIATION...Sugden
Area Forecast Discussion
National Weather Service Quad Cities IA IL
907 PM CDT Tue Oct 29 2024
...Updated for cancellation of Wind Advisory...
.KEY MESSAGES...
- Gusty winds the rest of tonight, but likely below advisory
criteria.
- Widespread showers and storms are expected Wednesday through
Thursday morning. There is a Marginal risk (level 1 of 5) for
severe storms Wednesday afternoon and evening.
- Seasonable temperatures and dry conditions late in the work
week, with an active weather pattern returning next week.
&&
.SHORT TERM /THROUGH TONIGHT/...
Issued at 212 PM CDT Tue Oct 29 2024
Tonight...strong WAA to continue with the winds decreasing just
below advisory levels after 10p, as the winds decouple. Clouds
will keep temperatures very warm overnight, with lows only
dropping into the upper 60s.
Active weather continues in the extended. A deep trough will move across
the northern Plains into the Midwest by 12z Thu. Another warm and
windy day is on tap for the area Wednesday, with the entire CWA
fully in the warm sector. Highs in the upper 70s/low 80s are
forecast, which is just shy of records for the day. A cold front
will track across Iowa through the daylight hours, with a wave of
low pressure moving along it. Strong moisture transport evident of
model PWs increasing to 1.5" (250% of normal) and upper level
dynamics support widespread showers and thunderstorms developing
along and behind the front. A dprog/dt of QPF reveals that the
highest totals over 1 inch has shifted west over the past 36
hours. Areas west of a line from Ottumwa to Dubuque now have the
highest probabilities of receiving 1" or more. Most areas are
progged to see 0.3" to 0.75" rainfall.
Taking a look at severe potential, SPC has maintained a Marginal
risk (level 1 of 5) for Wednesday for the entire forecast area.
This makes sense due to the strong winds aloft, and will be
mentioned in the hazardous weather outlook. The limiting factor
will be instability, with forecast soundings maintaining a tall
skinny CAPE profile. That said, it doesn`t take much instability
to develop strong to severe storms with strong dynamics. An
interesting note from the 00z HREF CAPE/Shear joint
probabilities prog shows 40-60% likelihood of 500 J/Kg and 30kts
of 0-6 km shear Wednesday afternoon just to our west. The HRRR
spreads the area of showers and thunderstorms across the area
Wednesday night, gradually diminishing after midnight as it
pushes into Illinois.
&&
.LONG TERM /WEDNESDAY THROUGH TUESDAY/...
Issued at 212 PM CDT Tue Oct 29 2024
Active weather continues in the extended.
Rains should end Thursday morning, possibly a few hours after 12Z in
Illinois. Thursday appears a dry, breezy, cooler day in the 50s.
Halloween evening should see decreasing winds, temperatures in the
mid 40s to near 50, and dry conditions for any Halloween activities.
Looking farther out, this weekend continues to appear wet as a
deep trough builds into the Southwest CONUS, with active,
moisture rich, southwest flow over the Midwest. A prolonged
period of rain and thunderstorms is forecast by nearly all
members of GEFS output, and strongly supported by the WPC
precipitation output. While the NBM spread in 72hr QPF values
ending 12z Tues remains high, most members show our CWA
receiving at least an inch of rain! An active start to the month
of November for sure and forecast rainfall if it verifies to
put a sizable dent in the ongoing drought!
&&
.AVIATION /00Z TAFS THROUGH 00Z WEDNESDAY/...
Issued at 615 PM CDT Tue Oct 29 2024
Winds will remain gusty at times tonight into Wednesday from a
southerly direction ahead of a slow approaching cold front.
Gusts of 25-35 kt are possible. If the gusts remain toward the
higher end of that range or even a little above then it could
reduce impacts of low level wind shear (LLWS). However, with
models showing a 50-55 kt wind increasing around 2kft agl
tonight with the LLJ we`ve kept the mention of LLWS in the TAFs.
Later tonight through midday Wednesday there is some signal for
potentially a few elevated higher based showers within a warm
advection regime. Confidence is too low on occurrence and
impacts at a TAF site to include any mention at this time.
However, the shower and storm chances look to really increase
just beyond the end of the TAF period (00-06z Thursday), as the
cold front moves in. Strong gusty winds and hail will be primary
threats with a few of the storms.
&&
.CLIMATE...
Issued at 323 AM CDT Tue Oct 29 2024
In addition to the record potential today and tomorrow, the
latest CPC 8-14 Day precipitation outlook depicts greater than
a 70% chance of near and/or above normal precipitation for the
Nov 5th-11th time period.
Record High Temperatures:
October 29:
KBRL: 85/1937
KCID: 84/1937
KDBQ: 85/1937
KMLI: 84/1937
Record High Minimum Temperatures:
October 29:
KBRL: 64/2004
KCID: 63/1946
KDBQ: 65/1946
KMLI: 68/1946
October 30:
KBRL: 62/1927
KCID: 61/1901
KDBQ: 62/1901
KMLI: 61/1927
&&
.DVN WATCHES/WARNINGS/ADVISORIES...
IA...None.
IL...None.
MO...None.
&&
$$
SHORT TERM...Gross/Haase
LONG TERM...Uttech/Haase
AVIATION...McClure
CLIMATE...Gross
Area Forecast Discussion
National Weather Service Kansas City/Pleasant Hill MO
618 PM CDT Tue Oct 29 2024
.KEY MESSAGES...
- Gusty winds 40-50 MPH continue through today and likely into the
overnight
- Showers and thunderstorms move through tomorrow afternoon and evening.
Some strong to severe storms with all hazards possible.
Damaging winds are the primary hazard, but hail and a couple
tornadoes are possible.
- Uncertainty of strong to severe storms remains as the high
shear relatively low CAPE environment adds uncertainty
ranging from several severe storms possible to none.
- Long term outlook appears more active and wet with a potential for
excessive cumulative rainfall over the coming days.
&&
.DISCUSSION...
Issued at 240 PM CDT Tue Oct 29 2024
A stout high to the east and a digging trough to the west is
creating compressing the pressure gradient across the central CONUS.
Solar heating mixes fast moving upper level winds down to the
surface resulting in wind gusts around 40-50 MPH across the region.
A Wind Advisory remains in effect through 7 AM Wednesday; however,
observations will tell if the lower level jet is able to decouple
during the overnight which may curtail gusts until sunrise where
gusts accelerate again around 30-40 MPH ahead of the arrival of a
cold front.
The cold front associated with this western trough pushes more
aggressively eastward tomorrow. This acts as a rather brute force
lifting mechanism to the conditionally unstable air. Warm air and
moisture advection this afternoon partially destabilizes with lapse
rates hanging around 7 C/km, meaning that any influx of
moisture or temperature could push stability one way or the
other. This makes the outlook over the next 36 hours somewhat
uncertain. Forecast guidance has been pretty consistent on a
high shear, relatively low CAPE environment with the front
being the primary driving force. This adds confidence in the
chances for precipitation; however, it also adds uncertainty on
the magnitude and severity of potential storms. While high shear
does help maintain thunderstorms that form, it may also be so
much that it shears them apart before they have a chance to
really organize. Depending on what side of stability the
environment lands on could really determine the magnitude of
storms. Again, confidence is high that we will see precipitation
tomorrow. It is just a matter of the strength of storms and
timing. The primary uncertainty of storm magnitude lies south of
the MO/IA border with higher chances for strong to severe
storms even further south across E and SE KS. Far eastern KS and
western MO remain a little more nebulous. Recent RAP analysis
has increased the available CAPE for the region around 1000-1500
J/kg which is more than enough for facilitate strong to severe
storms. Earlier most ensemble members where outputting CAPE
values around 500-1000 J/kg, which is still enough to get
isolated strong to severe storms.
Precipitation is expected to develop fairly quickly along the front
likely west of the CWA. This could open up the possibility of
multicell interactions where updrafts and anvil debris may
interfere with each other limiting the overall strength of
storms. That said the overall linear storm mode, CAPE and DCAPE
nearing 1000 J/kg, and the likelihood for some descending rear
inflow along the line points toward enhanced chances for severe
wind. Elevated bulk shear and helicity values present some
opportunity for tornadoes; however, hodographs, while somewhat
curved, are relatively stretched; so the potential looks low and
limited temporally. One inch hail also is possible with the
slight increase in CAPE. Overall, these high shear, marginal
CAPE scenarios present a significant challenge as minor
alterations in atmospheric variables can lead to potentially
expansive severe weather or none at all. Timing continues to
trend more slowly with storms entering the region mid afternoon
and remaining into the overnight.
Cooler conditions come behind the front for Halloween night. Highs
Thursday reside in the upper 50s with evening temperatures sinking
to the low 50s. Overnight lows dip back into the upper 30s. As
seemingly typical for this time of year, the temperature pattern
appears sinusoidal fluctuating between above and below normal.
The extended forecast looks much more active for the coming days
with multiple waves bringing opportunities for precipitation.
In fact, the concerns may shift from being too dry to getting
too wet too quickly with long range precipitation outlooks
trending above normal and PWAT values suggesting opportunities
for concentrated areas of heavy rainfall.
&&
.AVIATION /00Z TAFS THROUGH 00Z WEDNESDAY/...
Issued at 617 PM CDT Tue Oct 29 2024
VFR conditions prevail through the overnight hours with breezy
conditions persisting. Southerly wind gusts over 30 knots on
occasion will be possible tonight. There are subtle hints of
MVFR ceilings developing during the morning hours tomorrow,
though certainty is low at this time. Gusty conditions will
continue throughout the daylight hours, with bursts over 35
knots expected due to diurnal mixing. Ceilings are forecast to
lower tomorrow afternoon (20-21Z) with showers and storms
traversing the terminals from the west during said timeframe.
&&
.EAX WATCHES/WARNINGS/ADVISORIES...
MO...Wind Advisory until 7 AM CDT Wednesday for MOZ001>008-011>017-
020>025-028>032-037>039-043-044-053.
KS...Wind Advisory until 7 AM CDT Wednesday for KSZ025-057-060-
102>105.
&&
$$
DISCUSSION...Pesel
AVIATION...Hayes
Area Forecast Discussion
National Weather Service Green Bay WI
1050 PM CDT Tue Oct 29 2024
Updated aviation portion for 06Z TAF issuance
.KEY MESSAGES...
- Well above normal temperatures continue through Wednesday.
Besides several record highs already set this afternoon, record
highs will be possible again over many locations again on Wednesday.
- There is potential for heavy rainfall and thunderstorms from
Wednesday afternoon through Thursday morning. Localized urban
flooding will be possible, especially where storm drains are
clogged by fallen leaves. Isolated strong wind gusts will also
be possible with any thunderstorms or heavier showers.
- An extended period of hazardous boating conditions will continue through
Thursday evening.
&&
.DISCUSSION...
Issued at 251 PM CDT Tue Oct 29 2024
Short Term...Tonight and Wednesday
The latest RAP analysis and satellite/radar imagery show deep
southwest flow across the western Great Lakes ahead of a potent
trough centered over the intermountain west. At the surface, a
warm front is lifting north across central Wisconsin where
temperatures are in the middle and upper 70s south of the front,
but remain only in the lower 70s north of the front. Not too far
upstream, a cold front is draped from southwest Minnesota to far
northwest Wisconsin early this afternoon. Skies are mostly clear
south of the warm front, while partly to mostly cloudy conditions
exist along the cold front and north of the warm front. Focus in
this part of the forecast revolves around record temps and
shower/thunderstorm trends.
Tonight...While the warm front lifts north into the Upper
Peninsula, the cold front will remain nearly stationary as a wave
of low pressure travels along the boundary and into southern
Minnesota. Strong southerly flow of 40-50 kts will transport
increasing amounts of low level moisture northward across the
region. This moisture will boost elevated instability over the
course of the night. However, due to a large cap centered around
8000 ft, much of this instability exists well above the inversion,
and therefore, chances of thunderstorms look relatively low.
Furthermore, ample dry air exists in the mid-levels and
consequently, convective allowing models have backed off of precip
coverage tonight. Have therefore trended precip lower tonight.
In terms of temps, very mild temperatures are forecast. Record
high min temps range from the lower 50s to lower 60s on October
30. With lows forecast to range from the upper 50s to nearly upper
60s, most locations are expected to shatter their record high
mins.
Wednesday...The wave of low pressure will continue to track
northeast across northwest Wisconsin and the Upper Peninsula of
Michigan. This surface wave along with height falls aloft will
give the cold front a push to the east and arrive over north-
central Wisconsin by midday and central Wisconsin in the
afternoon. With arrival of the front, rain chances will increase
from northwest to southeast starting around midday in the north.
While not that impressive, instability of 300-500 j/kg will be
developing over northeast WI ahead of the front, but some capping
will likely hold back convection until late in the afternoon. If
thunderstorms develop, it will probably be close enough to peak
heating to where gusty winds to 40 mph and small hail will be
possible.
Temperatures ahead of the front will be most favorable for
record highs ie. the Fox Valley and lakeshore. Highs are forecast
to range from the middle 60s in the north to middle 70s over the
Fox Valley.
Long Term...Wednesday Night Through Tuesday
Main focus of the long term forecast revolves around a dynamic low
pressure system that is progged to cross the region Wednesday night
through Thursday. Periods of moderate to heavy rainfall along with
isolated thunderstorms are expected as this moves across the area.
Precipitation...WAA/f-gen driven rain is likely to be ongoing to
start the long-term period as a closed upper-low progresses
northeast across the northern Plains. Frontogenetic forcing is
expected to strengthen late Wednesday night into Thursday morning just
ahead of a slow moving cold front. Ample low and mid-level moisture
will advect into the area ahead of the aforementioned cold front
with PWATs forecast to reach 1.25-1.50", which would exceed the
daily climatological max. The strong forcing and ample moisture will
likely lead to efficient warm rain processes resulting in periods of
heavy rain through Thursday morning. Most long-range ensembles
members and deterministic models show the heavies band of rainfall
developing from the WI/MN/IA tri-point through northeast WI.
Rainfall should lighten up Thursday afternoon/evening as the
strongest forcing exits the region, but scattered showers may
persist as the cyclonic flow around the low lingers over the region.
NBM probs show an 80-90% chance for greater than 1" of rain through
Thursday evening for areas north and west of the Fox Valley, with a
40-60% chance in east-central WI. Locations in central and northeast
WI, where the heaviest rain is expected, have a 40-60% chance for
greater than 2". While most may welcome the rain given the on-going
drought conditions there is a chance for minor urban and street
flooding, especially if storm drains become clogged with fallen
leaves.
As 850 temps cool to -4 to -5C there is a chance for lingering showers
to become a rain/snow mix then all snow across far north-central WI
Thursday night into Friday morning. There also appears to be a brief
window overnight where winds turn to the northwest which may help to
induce some lake effect snow across northern Vilas County. Snowfall
amounts are still widely variable, however, there is a decent signal
(50-70% chance) that areas of north-central will see their first
measurable snowfall of the year.
Expect a return to dry weather for much of Friday and Saturday as a
brief period of high pressure sets in over the region. The next
chance for rain (40-60%) looks to come late Saturday into Sunday as
a WAA regime and surge of Gulf moisture move over the region. At
this point the risk for any thunderstorms during this time looks
low.
Winds...In addition to the rain, Thursday will be another breezy day
across the region. With a tightening pressure gradient due to the
passing surface low and winds just off the surface (2-3kft) around
35-40kts there will the potential for gusts to reach 25-35mph,
strongest in the Fox Valley. Expect winds to weaken by Friday with
calmer conditions expected for this weekend.
&&
.AVIATION...for 06Z TAF Issuance
Issued at 1050 PM CDT Tue Oct 29 2024
VFR conditions and gusty southerly winds continue over the area as
the region is well into the warm sector of an approaching low. A
mid-level deck around 5k ft continues to spread east ahead of an
approaching cold front. CIGs will lower to MVFR across north-
central Wisconsin Wednesday morning as showers develop across
central and north- central Wisconsin late Wednesday morning into
early Wednesday afternoon. Showers and a few thunderstorms will
then become ubiquitous Wednesday afternoon as the cold front
marches eastward through Wisconsin. Mainly showers and a few
thunderstorms will then be expected Wednesday night along the
front tracks through the area.
A prolonged period of LLWS is expected through mid-Wednesday
morning. The gusty winds aloft will then mix to the surface later
Wednesday morning.
&&
.MARINE...
Issued at 251 PM CDT Tue Oct 29 2024
Will extend the Small Craft Advisory through Wednesday night, but
it will likely need to be stretched out through Thursday evening.
Gusts to 25 to 30 kts will be possible through much of the
period, but stable conditions over the water should limit
potential for gale force gusts. Waves will build to 5-9 feet on
Lake Michigan and 3-6 feet on the bay.
There may be a brief lull in the in winds over Green Bay on
Wednesday night. But am reluctant to end small craft advisories
given a quick wind shift to the northeast is expected.
&&
.CLIMATE...
Issued at 251 PM CDT Tue Oct 29 2024
Unseasonably warm air will push into the region, bringing record
or near warmth through Wednesday (10/30). Several high and high
minimum temperature records may be reached. Here is a look at the
record and forecast highs for the GRB climate sites:
Green Bay
Date Record High Forecast High
------------------------------------------------------
10/30 75 (1901) 77*
On record, the latest 80 degree temperature during the
fall occurred on Oct 23, 1899 (81F).
Rhinelander
Date Record High Forecast High
------------------------------------------------------
10/30 79 (1950) 70
Wausau
Date Record High Forecast High
------------------------------------------------------
10/30 78 (1950) 73
On record, the latest 80 degree reading during the fall
occurred on Oct 27, 1927 (80F).
* Record high temperature forecasted.
&&
.GRB WATCHES/WARNINGS/ADVISORIES...
None.
&&
$$
DISCUSSION.....MPC/GK
AVIATION.......Kurimski
MARINE.........MPC
CLIMATE........MPC
Area Forecast Discussion
National Weather Service North Platte NE
624 PM CDT Tue Oct 29 2024
.KEY MESSAGES...
- The Red Flag Warning will continue across southwest Nebraska but
the forecast is supported by just a minority of model solns,
namely the GFS.
- The next significant weather system to affect wrn/ncntl Nebraska
is across the Gulf of AK this afternoon. It may affect the
region Saturday, Sunday and Monday but the forecast is very
uncertain. The ECM, GFS and GEM ensembles are all painting the
best rain chances south and east of wrn/ncntl Nebraska across
KS.
&&
.SHORT TERM /THROUGH WEDNESDAY NIGHT/...
Issued at 355 PM CDT Tue Oct 29 2024
992mb sfc low pressure across nern Colorado this afternoon will
fill and rapidly lift northeast through ncntl Nebraska this
evening with a cold front and strong cold air advection to follow.
The cold air advection will become neutral Wednesday with h850mb
temperatures hovering around 0C during the day and overnight into
Thursday morning. The temperature forecast Thursday morning gets a
mark- up across ncntl Nebraska where mid level cloud cover may
linger. Lows in the 20s are still on track across wrn Nebraska.
There is little change in the temperature forecast tonight and
Wednesday; the model consensus suggested lows in the 30s and highs
in the 40s.
The rain forecast uses the short term model plus the RAP, NAM and
GEMregional models. Given the lack of prominent synoptic scale focus
and forcing shown in the models, POPs are limited to 50 percent. The
upper level low across swrn WY this aftn will move slowly northeast
and be located across cntl SD by Wednesday evening, and cntl MN by
Thursday morning. The POP forecast is similar to the HREF which
suggests isolated showers across ncntl Nebraska tonight with a band
of more organized rain across nwrn Nebraska. Scattered showers
should move through wrn Nebraska during the day Wednesday as the
upper low and PV approaches the region. This rain would affect ncntl
Nebraska Wednesday evening with just isolated showers after midnight.
Snow chances across nwrn Nebraska are very slim. Snow levels this
afternoon across WY are around 5000ft and predicted to lower to
around 4500ft across nwrn Nebraska tonight. The forcing for rain is
very weak in the RAP model suggesting rain rates will be light and
more likely to be affected by boundary layer heating from the warm
ground. A rain or snow chance with lows just above freezing are in
place for this reason.
&&
.LONG TERM /THURSDAY THROUGH TUESDAY/...
Issued at 355 PM CDT Tue Oct 29 2024
The next significant weather system to affect wrn/ncntl Nebraska
is across the Gulf of AK this afternoon. It may affect the
region Saturday, Sunday and Monday but the forecast is very
uncertain. The ECM, GFS and GEM ensembles are all painting the
best rain chances south and east of wrn/ncntl Nebraska across KS
and the reason for this is the upper level support, a closed
low, will track south of Colorado and through the srn Plains for
the most part.
The approaching long wave trof in the models produces h850mb warm
air advection into Nebraska Saturday and Sunday with temperatures
rising to 10C - 15C at h850mb but the sfc temperature response is
very modest with highs projected in just the upper 50s to lower 60s.
There is a chance warmer temperatures will occur, especially since
the GFS and ECM show Nebraska wedged between belts of upper level
moisture across the Rockies and the srn Plains. Mostly clear or
partly cloudy skies may result and mild weather may result.
Otherwise, the models are in very good agreement tracking the
ongoing storm into the Great Lakes Thursday. Pacific-Canadian sfc
high pressure will build through the Great Plains in the storm`s
wake presenting cool weather across Nebraska Thursday and Friday.
&&
.AVIATION /00Z TAFS THROUGH 00Z THURSDAY/...
Issued at 620 PM CDT Tue Oct 29 2024
A cold front will continue tracking southeast across western and
north central Nebraska through this evening. Winds will be gusty
out of the north/northwest at 20 to 25 kts. Ceilings will begin
to lower across the Sandhills into northern Nebraska overnight
with widespread MVFR CIGs expected. These lowered CIGs will
spread from northwest to southeast across the area through
sunrise on Thursday, remaining in place through the remainder of
the period.
&&
.FIRE WEATHER...
Issued at 355 PM CDT Tue Oct 29 2024
Red Flag Warning swrn Nebraska This afternoon and early
this evening...
There is evidence on the KGLD radar wind profiler (VWP) that the
cold front which swept into swrn Nebraska this morning is very
shallow. South winds 30-40kts are depicted at the lowest gate of the
radar and if this is true, then there is a chance the warm front
accompanied by gusty winds will sweep into swrn Nebraska late this
afternoon.
The Red Flag Warning will continue but the forecast is supported by
just a minority of model solns, namely the GFS. The other models
maintain light east or southeast winds, cooler temperatures and
higher humidity. Critical fire weather conditions are not indicated.
&&
.LBF WATCHES/WARNINGS/ADVISORIES...
Red Flag Warning until 8 PM CDT /7 PM MDT/ this evening for
NEZ210-219.
&&
$$
SHORT TERM...CDC
LONG TERM...CDC
AVIATION...Viken
FIRE WEATHER...CDC
Area Forecast Discussion
National Weather Service Lake Charles LA
958 PM CDT Tue Oct 29 2024
...New UPDATE...
.UPDATE...
Issued at 952 PM CDT Tue Oct 29 2024
Area radar shows showers streaming out of the Gulf into SE TX
tonight, which the latest HRRR guidance has captured fairly well.
Guidance depicts light shower activity continuing to stream
inland through the next several hours, increasing in coverage
tomorrow morning. Therefore, went ahead and added small POPs into
the forecast for SE TX and far SW LA for the remainder of the
overnight period. Otherwise, the forecast is on track tonight,
with another warm and muggy one on tap.
17
&&
.SHORT TERM...
(Tonight through Thursday night)
Issued at 250 PM CDT Tue Oct 29 2024
A bit of a pressure gradient across the forecast area this
afternoon from a high pressure system over the Mid-Atlantic states
and a low east of the southern Rockies. This has allowed for some
breezy southeast winds bringing Gulf moisture to provide partly
cloudy skies and humid conditions.
Boundary layer winds will stay up tonight to preclude any
widespread fog with just low clouds and muggy conditions.
The upper level ridge across the southeast US will breakdown
somewhat and move off to the east. This will allow the tail end of
a short wave moving out of the northern Rockies across the
northern Plains over the next couple of days, help push a weak
cold front into the region, stalling just north of the forecast
area.
Plenty of Gulf moisture will be increasing across the forecast
area with a modest and deep southerly flow. PWAT values will be
over the 90th percentile of daily climo value of 1.75 inches by
Wednesday, then climb to around or above 2 inches and near moving
max values on Thursday.
Forecast area will begin to feel the lift from the approaching
system on Wednesday, with light streamer type showers moving in
during the early morning, then combining with daytime heating to
produce scattered showers and thunderstorms in the afternoon, with
the better probability for southeast Texas.
Unfortunately (or fortunately) Thursday being Halloween, looks
like the potential to be the wettest day in quite some time. The
copious amounts of Gulf moisture will collide with the frontal
convergence and favorable upper level conditions, to produce
widespread showers and thunderstorms by afternoon that will
gradually taper off in the evening hours.
The highly anomalous moisture values of PWAT over 2 inches and
mean layer relative humidity values over 80 percent, will bring
about high rainfall rates where convection can take advantage of
the pockets of high instability of CAPE values over 2000 j/kg.
There is also the potential for the mean flow to become parallel
to the surface boundary and the theta-e ridge that could also all
for some training of the storms. We have been very dry lately, so
for now WPC has the forecast area, mainly north of I-10, outlined
in a Marginal Risk (risk level 1 out of 4) or about a 5 percent
chance of seeing excessive rainfall. Again, with hydro levels low
and grounds dry, and flooding type issues would be of the urban
street type.
If we can get some breaks in the clouds and good heating and those
pockets of high instability develop, then convection can become
rather strong, although shear values look weak, and lapse rates
modest, so isolate strong wind gusts would be the main concern.
SPC in their Day 3 Outlook have a Marginal Risk (Risk level 1 out
of 5) or a 5 percent chance for severe weather just to the north
and northwest of the forecast area.
Rua
&&
.LONG TERM...
(Friday through next Monday)
Issued at 250 PM CDT Tue Oct 29 2024
The frontal system will stall north of the forecast area on
Friday, before getting pushed back to the north over the weekend.
Therefore, unseasonably warm and humid conditions look to continue
with some chances for shower activity, mainly with daytime heating
in the afternoon.
Rua
&&
.AVIATION...
(00Z TAFS)
Southeast winds around 12-16 kts with gusts 20-24 kts expected to
continue for the next couple of hours, only diminishing slightly
to around 7-10 kts later this evening and overnight, preventing
any fog formation. MVFR ceilings expected at AEX/BPT/LCH around
08z through roughly 15z Wednesday. Thereafter, southeast winds
12-16 kts with gusts 20-24 kts expected once again. Increased
moisture and lift will bring VCSH at BPT/LCH/AEX, with the highest
chances at BPT for afternoon TSRA with a PROB30 group from 18-24z.
08/DML
&&
.MARINE...
Issued at 250 PM CDT Tue Oct 29 2024
Southeast winds increasing this afternoon with building seas as
pressure gradient between high pressure over the Mid-Atlantic
states and low pressure east of southern Rockies tightens. Looks
like sustained winds just over 20 knots for the waters beyond 20
nm and seas over 7 feet into Wednesday will necessitate a Small
Craft Advisory.
Winds will decrease somewhat later on Wednesday into Thursday as
a surface frontal systems nears the coast and the gradient
weakens.
The frontal system will work with deep Gulf moisture to provide a
chance for showers as early as Wednesday morning, with chances
increasing on Thursday.
The frontal system will stall on Friday then move back to the
north. Therefore, a modest onshore flow will continue a long with
a chance for showers through the weekend.
Rua
&&
.PRELIMINARY POINT TEMPS/POPS...
AEX 67 87 68 81 / 0 20 30 80
LCH 71 85 72 81 / 10 40 30 80
LFT 70 87 73 84 / 0 20 10 70
BPT 72 84 72 83 / 30 60 40 80
&&
.LCH WATCHES/WARNINGS/ADVISORIES...
LA...None.
TX...None.
GM...Small Craft Advisory until 1 PM CDT Wednesday for GMZ470-472-475.
&&
$$
SHORT TERM...07
LONG TERM....07
AVIATION...08
Area Forecast Discussion
National Weather Service Twin Cities/Chanhassen MN
625 PM CDT Tue Oct 29 2024
.KEY MESSAGES...
- Near-record warmth across southeastern Minnesota/western
Wisconsin this afternoon. See the climate section below for
more details.
- Wednesday is trending drier for most locations, as the main
axis of showers and isolated thunderstorms has shifted
towards southeast Minnesota and northeast Iowa.
- "Boom-or-bust" snowfall setup Thursday morning across east
central Minnesota and western Wisconsin. Accumulating snow is
possible.
- Temperatures modify to more seasonal levels this weekend. The
continuation of an unsettled pattern will bring rain chances
this weekend and into next week.
&&
.DISCUSSION...
Issued at 240 PM CDT Tue Oct 29 2024
Satellite and surface observations reveal quite the spread in
weather conditions across the region early this afternoon. A frontal
boundary is draped from southwest to northeast across southern
Minnesota, with varying weather conditions on either side. Several
locations have already warmed into the 70s east of the front, with
the potential for record-setting highs this afternoon. The picture
is much different north and west of the boundary, as temperatures
have struggled to warm out of the 50s/60s due to a layer of stratus
overhead. The Upper Midwest is positioned within a baroclinic zone
between upper level troughing in the west and ridging over the Great
Lakes. An initial shortwave trough will eject to the northeast
across the northern Great Plains this evening, with associated
surface low pressure progged to move northeast along the thermal
gradient into southwestern Minnesota. Forcing tied to the shortwave
will combine with broad isentropic ascent, favorable moisture
return, and mid-level frontogenesis to produce a band of rain across
northern Minnesota overnight. While we cannot rule out showers along
and north of I-94, the latest thinking is that much of south central
Minnesota will run dry tonight. The focus then shifts to the south
across Iowa, where the eastward movement of the aforementioned
frontal boundary will combine with the nocturnal low-level jet to
produce rain and potentially isolated thunderstorms. RAP guidance
illustrates a plume of ~500 J/kg of CAPE extending from roughly
Albert Lea to Ladysmith around daybreak tomorrow. There has been a
notable eastward shift of the instability axis/LLJ position, such
that much of the focus for wet weather will be across southeastern
MN/western WI through Wednesday afternoon and our PoPs have trended
lower through the daytime hours west of this axis.
The longwave upper trough currently over the Rockies is forecast to
become negatively tilted by late Wednesday/early Thursday as it
moves across the Great Plains. Strong ascent in the exit region of
the jet will promote deepening of the surface low as it moves from
roughly central Iowa to the northeast towards LaCrosse/Madison WI.
This track puts central-southern Minnesota and western central
Wisconsin in a position northwest of the surface low. PoPs will
increase as a shield of precipitation lifts north ahead of the
surface low Wednesday evening into very early Thursday, however
guidance continues to advertise that its southeast Minnesota
and western Wisconsin that will receive the bulk of the precipitation.
In short, it looks like two rounds of rain, one tonight in northern
Minnesota and one through Wednesday/Wednesday night in southeastern
Minnesota and western Wisconsin. Rainfall amounts remain somewhat
in flux given less of a focus on convection than in previous
forecasts. The overnight shift referenced an inch spread in
rainfall amounts along a line from Albert Lea to Eau Claire and
that theme remains largely unchanged after analyzing the
25th-75th percentiles of the 12z HREF. It looks like it`s going
to come down to just how far south/east the surface low tracks.
A rather sharp cut-off is likely to the west across much of
south central Minnesota given the systems dry slot winning out.
Now onto the part of the forecast that features the greatest
uncertainty, while also causing the most amount of chatter online:
Potential Halloween Snow. Guidance is in relatively strong
agreement that the surface low will deepen as it moves from Iowa
into Wisconsin by Thursday morning. The degree of strengthening
is somewhat in flux and will have major implications on the
evolution of the forecast through the first part of Thursday.
South central Minnesota and western Wisconsin will be positioned
in a deformation zone to the northwest of the surface low. At
the very least, this positioning will introduce the best chance
for widespread QPF across much of the area as the system begins
its departure to the east. What is more uncertain is the
potential for a rain/snow mix, along with a band accumulating
snow. A glance at model soundings across eastern MN/western MN
around 12z Thursday reveal an environment characterized by deep
saturation and strong omega forcing through the column. Thermal
profiles above freezing at the beginning of the time period are
progged to dynamically cool below freezing around/shortly after
daybreak, given the ongoing cold air advection regime and strong
forcing. The degree by which the environment cools will be
largely dependent on the large scale cyclogenesis set to occur
across the Upper Midwest, and thus how much cold air can wrap
into the system. Should cyclogenesis occur, the sub-freezing
thermal profile will set the stage for a changeover to snow and
a potential quick "thump" of banded snow somewhere across far
eastern MN/western WI. On the flip side, large scale convection
in the warm sector may slow the cyclogenesis process, resulting
in an open upper wave and less efficient dynamic cooling. This
would mean less in the way of snow, let alone a transition to
wintry precipitation. For this reason, this forecast carries a
high degree of "boom-or-bust" potential. The eventual outcome
will likely be somewhere in between, with a brief period of
heavy snow on the table from the Thursday morning commute until
late morning. It`s tough to narrow down the location of the
band, even within 48 hours, given the myriad of solutions on the
table (particularly from north- central MN through southwest
WI). We`d encourage folks to refrain from subscribing to the
bullish output from any single model solution, given the
multitude of parameters that need to come together for heavy
snow to occur and low ratio nature of the snowfall. Should
efficient dynamic cooling occur, it`s within the realm of
possibilities that snow may be heavy enough to accumulate
Halloween morning -- but again, this will likely occur over a
narrow band with the majority of the area witnessing more of a
low-impact snow or perhaps just rain.
Northwest winds will remain gusty Thursday, behind the departing
surface low. Instantaneous gusts may reach 30-35 mph. The
northwesterly flow will keep temperatures below normal for Thursday,
with highs in the 40s. Thermal ridging will build across the Plains
this weekend, with warm advection set to increase locally. High
temperatures will modify back into the 50s/low 60s for the weekend.
Large scale troughing over the western CONUS will send several waves
towards the Upper Midwest this weekend and into early next week,
which will result in the return of scattered to potentially
widespread rain chances.
&&
.AVIATION /00Z TAFS THROUGH 00Z WEDNESDAY/...
Issued at 619 PM CDT Tue Oct 29 2024
Gradually lowering CIGS ahead of incoming -SHRA will be the
primary driver pushing us towards MVFR/IFR by end of period as
visibility generally should remain 5-6SM or higher through 00z
tomorrow. Winds will shift from approximately 180 to 300-330 as
a cold front moves through, with light showers gradually
spreading from west to east becoming more likely later in the
period. LLWS ahead of the front is expected across all sites
with a 5-7 hour duration as the front arrives and begins to move
through.
KMSP...Compared to the 18z TAF, mention of -SHRA has been
delayed as forecast soundings continue to indicate mostly dry
conditions through at least 22-00z, with the greater spread of
showers expected after 00z. MVFR/IFR will be driven by CIGS
rather than VIS as the initial onset of -SHRA should be fairly
light.
/OUTLOOK FOR KMSP/
THU...MVFR/IFR/-SHRA early. Wind NW 10-15G25kts.
FRI...VFR. Wind SE 5-10kts.
SAT...VFR. Wind S 10-15kts.
&&
.CLIMATE...
Issued at 324 AM CDT Tue Oct 29 2024
Record high temperatures were set in the Twin Cities (MSP) and
St Cloud (STC) yesterday. Record high max and min temperatures
will be possible today. Check the tables below for our climate
sites Twin Cities (MSP), St Cloud (STC), and Eau Claire (EAU).
Records listed below are the record highs.
Yesterday October 28
| Observed Max | Record Max |
----|----------------------------
MSP | 75 | 75 (1948) | Record Tied 2024
----|----------------------------
STC | 77 | 77 (2024) | New Record Set 2024
----|----------------------------
EAU | 72 | 74 (1896) |
Today October 29
| Forecast Max | Record Max | Forecast Min | Record Min |
----|--------------------------------------------------------
MSP | 80 | 78 (1922) | 60 | 56 (2004) |
----|--------------------------------------------------------
STC | 72 | 74 (1950) | 55 | 52 (1974) |
----|--------------------------------------------------------
EAU | 81 | 77 (1950) | 59 | 57 (2004) |
&&
.MPX WATCHES/WARNINGS/ADVISORIES...
MN...None.
WI...None.
&&
$$
DISCUSSION...Strus
AVIATION...TDH
CLIMATE...NDC
Area Forecast Discussion
National Weather Service Marquette MI
750 PM EDT Tue Oct 29 2024
.KEY MESSAGES...
- Temperatures stay well above normal through Wednesday before
returning to near normal behind a cold front. Some showers and
thunderstorms accompany this cold front.
- Breezy southwest winds are expected to gust to 20-30 mph on
Wednesday ahead of the cold front.
- A much needed 1 to 2 inches of rain is expected Wednesday
through Thursday between the passing cold front and a low
pressure system that lifts northeast over the area on
Thursday.
&&
.SHORT TERM /THROUGH TONIGHT/...
Issued at 340 PM EDT Tue Oct 29 2024
Water vapor imagery and RAP analysis show an amplified pattern
across the Lwr 48, featuring mid-level troffing over the Rockies and
ridging over the eastern U.S. A vigorous shortwave is noted within
the trof over ne UT. At the sfc, a slow moving cold front extends
from Hudson Bay across MN to CO. Ahead of the front, it is an
unseasonably warm late Oct day across Upper MI. Temps at 19z are in
the 60s F, but across much of central Upper MI where skies are
mostly sunny, temps have risen into the low/mid 70s F. Menominee is
the warm spot, reaching a toasty 79F so far.
An unusually warm night for late Oct is on the way as cold front
drifts e, only reaching the vcnty of the western shore of Upper MI
by 12z. Low-level jet of 40-45kt developing ne over the area tonight
will keep sfc winds stirring, and the air mass has an unusually high
moisture content with precipitable water running 250 to nearly 300
pct of normal (2.5 to 3.5 sigma) for this time of year. Both factors
will work to inhibit the temp fall tonight after an unseasonably
warm aftn. Expect min temps mostly in the upper 50s and lwr 60s F,
but would not be surprised at all to see temps in the mid/upper 60s
F at most locations for the majority of the night. Temps may
actually fall the most this evening and then rise a little as sfc
winds increase a bit. As low-level jet develops nne into the area,
isold/sct elevated shra/tsra are a possibility over the western
1/3rd or so of the fcst area. Fcst soundings indicate up to around
1000j/kg of CAPE for parcels lifted from around 5kft agl. There is
some CINH to overcome, so it`s uncertain if convection will fire.
With estimated effective deep layer shear for elevated convection at
around 30kt, some hail is a possibility if convection does in fact
fire and that convection is based from highest cape/deep layer shear
combo level.
&&
.LONG TERM /WEDNESDAY THROUGH TUESDAY/...
Issued at 335 PM EDT Tue Oct 29 2024
Upper air pattern consists of a 500 mb trough in the Rockies and a
ridge in the eastern U.S. 12z Wed. This trough moves out into the
northern and central plains 00z Thu with a negative tilt noted on
this. By 12z Thu, a closed 500 mb low forms in this negative tilted
trough over the upper Mississippi River Valley which then moves
through the upper Great Lakes on Thu and is then followed by
shortwave ridging on Fri. Rain starts to move in on Wednesday and
overspreads the area Wed afternoon before pushing to the south. A
resurgence of pcpn then moves back northward Wed night into Thu.
Could see 1 to 2 inches of rain between Wednesday and Thursday with
this system which would bring relief to the area for drought and
also fire weather. There will even be some snow in the higher
terrain late thu afternoon into the evening and could see up to an
inch of slushy accumulation in the grass across western Upper
Michigan higher terrain areas west of Ishpeming.
In the extended, the GFS and ECMWF show a deep and broad 500 mb
trough across the western U.S. 12z Sat with a ridge over the sern
U.S. This trough continues to amplify 12z Sun with the ridge
building into the eastern U.S. The trough moves into the Rockies 12z
Mon and into the plains 12z Tue. Temperatures continue to be above
normal for this forecast period. Another wet period starts on Sunday
into Tuesday for the area again.
&&
.AVIATION /00Z TAFS THROUGH 00Z THURSDAY/...
Issued at 743 PM EDT Tue Oct 29 2024
VFR will mostly prevail tonight across the terminals ahead of
slowly approaching low pres trough. That trof will progress
across Upper MI on Wed. A low-level jet developing ahead of the
trough may generate a few shra and possible tsra tonight across
western Upper MI. Potential of any of the terminals being
affected is low, but better chc is at CMX and IWD where VCSH
was included in fcst. The low-level jet will result in LLWS
developing at all terminals tonight into Wed morning. As the
trough arrives and passes IWD/CMX Wed morning, conditions will
fall thru MVFR to IFR with -shra becoming more likely. The
trough will reach SAW later in the afternoon as VFR conditions
lower to MVFR by 18Z and then IFR by 21Z in steady rain.
&&
.MARINE...
Issued at 335 PM EDT Tue Oct 29 2024
East to southeast winds stay below 20 kts across the lake into by
this evening. A cold front moves east across the the lake toward
the western shores of Upper MI late tonight. This backs winds north-
northeast behind the front, but south winds over the eastern third
of the lake increase to 15-25 kts ahead of the cold front late
tonight through Wednesday morning. North winds of 20-30 kts are
expected behind the cold front Wednesday. Winds stay 20-30 kts
Wednesday night, but they veer northeast as a deepening low pressure
lifts into the Upper Great Lakes. As this low pressure system lifts
northeast toward northern Ontario Thursday, the surface pressure
gradient tightens and colder air moves in over the warmer waters.
This will cause a northeast gale event of 35 knots across most of
the lake Thursday and issued a gale watch for this. Gales of 35
knots over the east half continue into Thursday night before high
pressure returns, diminishing winds to 20 kt or less across the lake
by Friday morning with the wind staying in that range into Friday
night. South winds increase to 15 to 25 knots on Saturday.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
Upper Michigan...
None.
Lake Superior...
Gale Watch from Thursday morning through Thursday evening for
LSZ243-244-264.
Gale Watch from Thursday afternoon through Thursday evening
for LSZ245-265-266.
Gale Watch from Thursday morning through Thursday afternoon
for LSZ263.
Lake Michigan...
None.
&&
$$
SHORT TERM...Rolfson
LONG TERM...07
AVIATION...Voss
MARINE...07