Forecast Discussions mentioning any of
"HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 01/01/25
Area Forecast Discussion
National Weather Service Green Bay WI
540 PM CST Tue Dec 31 2024
Updated aviation portion for 00Z TAF issuance
.KEY MESSAGES...
- Light snow and flurries are possible at times through tonight
that could bring a dusting of snow to the area. In general, no
significant snowfall is expected over the next week.
- Colder temperatures will arrive for the start of the New Year.
Sub zero wind chills are likely Thursday, Friday, Saturday and
Sunday nights across most of the region.
&&
.DISCUSSION...
Issued at 216 PM CST Tue Dec 31 2024
Short Term...Tonight and Wednesday
The latest RAP analysis and satellite/radar imagery show a dynamic
low pressure system moving across central Indiana and a cold
front moving across north-central to southwest Wisconsin early
this afternoon. This front has been mostly inactive so far today
due to a wedge of dry air in the mid-levels. A few flurries or
light snow showers have been observed over Vilas county, but
otherwise, light snow has remained over southern Wisconsin so far
today. As the cold front continues to move southeast, light snow
chances and impacts remain the main forecast concern.
The convective allowing models have backed off on light snow
chances this afternoon and evening despite modest mid-level
frontogenesis along the boundary. It appears the enhanced moisture
along the front trails just behind the better mid-level moisture,
thereby making deep saturation difficult to achieve. There may be
brief window between 5-9 pm where saturation increases above 5000
ft and the -10C isotherm when light snow is possible over the Fox
Valley and Lakeshore. Given the shallow nature of the saturation,
cannot see much more than a trace. This snowfall will largely
fall after the afternoon commute is over so this impacts will be
limited to a few slippery stretches at best.
After the front passes, cold advection continues with a scattered
lake effect snow showers near the U.P. border over far northern
Vilas county. Ample cloud cover exists upstream, so clearing
potential will likely be limited to the downslope areas of
northeast WI.
Temperatures will be colder on Wednesday with highs in the 20s.
Long Term...Wednesday Night Through Tuesday
The upper air pattern will become more amplified late this week
into early next week as a blocking ridge holds firm over Greenland
while ridging builds over northwest North America into the Arctic.
This looks to be a classic pattern for a cold air intrusion by the
middle of next week.
Temperatures: The biggest story over the next week will be the
gradually cooling temperatures that will make it feel more like
winter. 850mb temperatures will be trending colder from -15C on
Thu to -20C by Sat which will result in high temps mainly in then
teens on Sat. Temps moderate somewhat on Sun into Mon as a low
pressure system moves over the Ohio Valley, but then trend colder
again by next Tue.
Precipitation...Only low chances of snow are expected over the
next week. Lake effect parameters will be most favorable from
Thursday night to Friday night over the Vilas county snow belt,
but 850-700mb RH below 50% will limit accumulation potential.
The ensembles track a Rocky Mountain cyclone across the Ohio
Valley on Sunday into Monday that keep the highest chance of
greater than 1 inch of snow over central Illinois and Indiana.
Over northern Wisconsin, the probability of greater than 1 inch of
snow is only 10% which has decrease from about 25% 48 hours ago.
Only minor accumulations of light snow look possible early next
week.
&&
.AVIATION...for 00Z TAF Issuance
Issued at 540 PM CST Tue Dec 31 2024
MVFR ceilings and some snow flurries are expected across
the region through around noon New Year`s Day. Ceilings may rise
to VFR in the afternoon, especially east of a IMT to STE line.
&&
.GRB WATCHES/WARNINGS/ADVISORIES...
None.
&&
$$
DISCUSSION.....MPC/MPC
AVIATION.......RDM
Area Forecast Discussion
National Weather Service North Platte NE
519 PM CST Tue Dec 31 2024
.KEY MESSAGES...
- Ringing in the New Year with seasonal temperatures in the 30s
to low-40s on Wednesday. However, much colder air will usher
in below normal temperatures for the latter end of the week
and beyond.
- A quick moving system will bring light snow showers to
portions of the Panhandle and areas east of Highway 281
Wednesday night into Thursday morning with accumulations of 1"
or less expected.
- Large system poised to be at least nearby the local area this
weekend. Uncertainties on the strength and progression of
this system continue to result in low confidence on where and
how much snow is expected. Continue to monitor the forecast.
&&
.SYNOPSIS...
Issued at 201 PM CST Tue Dec 31 2024
Recent GOES-16 WV imagery and RAP 500-mb analysis showed a trough of
low pressure over southern portions of the Hudson Bay, extending
southwest into the Upper Midwest and northern Plains. A robust upper-
level shortwave was moving northeast across the Ohio River
Basin. Upper-level ridging was apparent over the west coast with
a weak PV anomaly ejecting east out of the Intermountain West.
All of these features combined has resulted in northwesterly
flow aloft across western and north central Nebraska. At the
surface, high pressure was building in across the region with 2
PM CT temperatures ranging from 24 degrees at Gordon to 34
degrees at North Platte. A stratus deck has been slow to burn
off from west to east with high level clouds moving in from the
west. Yesterday and last night`s system resulted in icy and snow
covered roadways over portions of north central Nebraska as
rain that occurred earlier in the day froze through the evening
and overnight. With the persistent cloud cover and temperatures
struggling to get above freezing for these areas, limited
melting has occurred. Looking at recent NDOT cameras, continue
to urge travelers to use caution across north and north central
Nebraska.
We are closing 2024 out with very mild conditions and zero
measurable snowfall for North Platte this 2024-2025 winter
season. Interestingly, as it stands now (not including today`s
CLI report), LBF has tied for the 4th warmest December on
record with an average temperature of 35 degrees.
&&
.SHORT TERM /THROUGH WEDNESDAY NIGHT/...
Issued at 201 PM CST Tue Dec 31 2024
Clouds will continue to clear out across north central Nebraska
overnight as temperatures fall into the low to mid teens. It
will be a pleasant day to ring in the New Year with temperatures
ranging from low to mid-30s over northwest and north central
Nebraska where snowfall recently occurred to the low-40s further
south. Skies will remain partly sunny with clouds increasing
from the west into the evening ahead of an approaching
disturbance. Surface low pressure will organize over central
Montana tonight with an attendant stationary front draping
southeast into the Nebraska Panhandle by Wednesday morning. As
the surface low advances southeast into the local area through
the day, mid-level warm air advection (WAA) and frontogenetical
forcing will increase behind the boundary western and north
central Nebraska. This will provide focus for flurries and light
snow showers to the Panhandle and areas generally east of
Highway 281. Short term model guidance continues to trend down
on snow accumulations for the previously mentioned areas.
Greatest potential for >0.5" resides along and east of Highway
281 and north of Highway 20, with the 12Z Tue run of NBM, LREF,
and HREF Probabilities of >1" Snowfall falling down to 20% or
less. Given this, light accumulations less then 1" are
anticipated with most locations only seeing a dusting at best.
Behind this quick hitting disturbance, surface high pressure
will begin to dig south out of Canada and Wednesday night
temperatures being comparable to tonight, generally in the low
to mid teens.
&&
.LONG TERM /THURSDAY THROUGH TUESDAY/...
Issued at 201 PM CST Tue Dec 31 2024
Despite remaining near normal for the start of January, Thursday
will mark the start of a trend towards much colder temperatures for
this weekend and next week. Daytime highs on Thursday will range
from the 20s across north central Nebraska to upper-30s across
southwest Nebraska. On Friday, upper-level ridging will attempt to
build in from the western US ahead of a deepening upper-level trough
over the cost of the Pacific Northwest. As this trough swings
southeast through the Four Corners into the southern Plains early
Sunday, surface low pressure will develop over northeast New Mexico,
becoming vertically staked in the process. This system will track
east-northeast into Oklahoma on Sunday, exiting into the Mid-
Mississippi Valley on Monday. A lot of questions remain in regards
to the evolution and strength of this system which will have impacts
on where and how much snow is expected. Model guidance continues to
highlight the heavier precipitation to occur further south and east
of the area. Fortunately, the cold temperatures will boost
confidence on if we do indeed see any precipitation with this
system, we can expect to see all snow. WPC`s Probabilistic WSSI
highlights the potential for winter weather impacts for areas along
and east of Highway 83 with a 20 to 30% probability for minor
impacts Saturday into Sunday. All this to say, light snow will be
the main story Saturday into Sunday but how much and precise
locations remains low confidence at this time. Those with travel
interests for this period should check future forecasts as the
details become more certain, especially if traveling south or east
into the Midwest. The colder airmass will certainly be felt this
weekend into next week with highs struggles to get out of the
10s and 20s with lows in the single digits.
&&
.AVIATION /00Z TAFS THROUGH 00Z WEDNESDAY/...
Issued at 515 PM CST Tue Dec 31 2024
Satellite imagery shows an expansive area of MVFR clouds from
central SD down through eastern NE with a rather sharp back
edge being obscured by higher clouds moving in from the west.
KVTN remains under the MVFR cloud deck and expect this will be
the case through the first couple of hours this valid period
with a transition to VFR by 06Z. However confidence in timing of
improvement is not high since guidance is struggling to resolve
the lower clouds so will amend as needed.
KLBF is outside the lower clouds with VFR higher clouds and
expect VFR will be the rule at KLBF through this valid period.
There may be some lower clouds moving in for a time before
daybreak but still expect VFR conditions so will not include any
TEMPO group for these conditions.
There is a hint at fog/stratus potential overnight/before
daybreak mainly across the sandhills but with no higher than a
10 percent chance for low clouds/fog at either KLBF of KVTN will
not mention in the TAF.
Winds will generally be light through Wednesday morning with
potential some low end gusts around 15kt Wednesday afternoon.
&&
.LBF WATCHES/WARNINGS/ADVISORIES...
None.
&&
$$
SYNOPSIS...Viken
SHORT TERM...Viken
LONG TERM...Viken
AVIATION...MBS
Area Forecast Discussion
National Weather Service Chicago/Romeoville, IL
556 PM CST Tue Dec 31 2024
.KEY MESSAGES...
- Chance of flurries or a few snow showers overnight into
Wednesday morning.
- Increasing potential for accumulating snow (probably an inch or
two) Thursday afternoon and evening, especially south of I-80.
- There`s another chance of snow Sunday/Monday, but confidence
in this threat is low.
&&
.DISCUSSION...
Issued at 134 PM CST Tue Dec 31 2024
Through Wednesday Night:
Light rain will slowly end from west to east later this
afternoon into the early evening. As it does, it may mix with
some wet snow, as it has been doing across the northwest cwa.
Not expecting any accumulation as temperatures remain above
freezing through at least early evening. The precipitation will
linger the longest across northwest IN and may not end there
until mid evening. There will then be a chance of flurries or
perhaps a few snow showers overnight into Wednesday morning. The
HRRR remains the most aggressive with snow showers and if its
solution were to materialize, then a few locations may see a
dusting of snow accumulation but currently do not have any
accumulation in the forecast.
Northwest winds will remain gusty tonight, into the 20-25 mph
range and perhaps back into the 30 mph range on Wednesday, then
diminish Wednesday evening. Low temps tonight will drop into
the low/mid 20s and may only recover into the upper 20s/lower
30s for highs Wednesday. Lows likely will drop into the upper
teens/lower 20s by Thursday morning. cms
Thursday through Tuesday:
A shortwave trough is still progged to break off the large upper
trough located off the west coast of Canada and shear quickly
east-southeastward across the Pacific Northwest tonight/Wed,
eventually reaching the mid-Mississippi Valley Thursday. Guidance
is in good agreement in this system remaining low amplitude and
quite progressive, though there has been a modest, but notable,
upward trend in model QPF associated with this feature as it moves
across IL Thursday afternoon and evening.
Forcing/omega is progged to be relatively muted and largely driven
by warm air advection as mid then low level flow backs in advance
of this feature leading to a subsequent strengthening of
isentropic ascent. GFS does hint at a weak transient
frontogenetical circulation developing, but as progged now, this
doesn`t look particularly strong or interesting. Time height
cross sections do show ascent through the prime dendritic growth
zone (DGZ), but the ascent in that layer is rather weak and
guidance show minimal, if any, supersaturation in the DGZ. So
unless guidance were to trend stronger with forcing in the DGZ,
snow type would likely be more needles/plates with snow:liquid
ratios (SLR) probably in the 10-15:1 range.
Given latest NBM/WPC QPF, those SLRs would support a band of an
inch or two of snow across IL Thursday afternoon and evening.
There`s still some spread in the track, but most favored area
still looks to be south of I-80, but some guidance is suggesting
some measurable snowfall as far north as the I-88/I-290 corridor.
Given the low amplitude nature of this wave, certainly plausible
that there could be some modest latitudinal adjustments in the
forecast track of this feature (and subsequent snow band) across
the region, so stay tuned.
Attention will then turn to the next trough forecast to move
across the country and potentially affecting our area during the
Sunday/Monday time frame. The 12z operational run of the GFS has
shifted farther south, more in line with the previous (and latest)
ECMWF runs, which would keep most of the accumulating snow south
of most of our CWA. There remain a number of ensemble members
from both the EPS and GEFS suite which do have a farther north
track, posing a greater risk of snow across most of our CWA. At
this distance, it is important not to focus too much on individual
model runs, but rather monitor longer term trends. Given the
uncertainties, made no adjustments to NBM grids, which still have
a snow chances across the area, favoring our southern CWA with the
highest chances. There will likely be additional adjustments in
the track and intensity of this system. The key takeaway at this
point is that it is too soon to say how much, if any, impact this
system will have on our CWA.
Seasonably cold (slightly below average) temperatures are
generally expected through the long range period. There continue
to be indications that there could be a more formidable push of
cold air during the 2nd week of January, just beyond the current 7
day period, so chances for a January thaw look dismal for the
foreseeable future.
Izzi
&&
.AVIATION /00Z TAFS THROUGH 06Z THURSDAY/...
Issued at 552 PM CST Tue Dec 31 2024
Ceilings are expected to gradually lift from lower MVFR to
higher MVFR levels through much of the period, with the
potential for clouds to SCT and/or reach VFR levels sometime
Wednesday afternoon or evening. NW winds gusting around 20 knots
early this evening will settle WNW overnight through Wednesday
with some gusts up to 25 knots during the daytime hours.
Precip has ended at the Chicago terminals early this evening
(except at GYY, where RA will end within an hour). A series of
weak mid-level waves extending from southeast Minnesota to
North Dakota will brush northern Illinois to the north overnight
through Wednesday afternoon. Existing stratus over the area
should be marginally deep for the generation of some flurries
with the first wave overnight to around sunrise. While some
upstream obs, including several moderate icing reports, indicate
that FZDZ may be occurring in far southeast Minnesota and
western Wisconsin, gradual cooling of the cloud layer over
northern Illinois should allow for snow overnight.
After sunrise Wednesday, cloud depths are expected to diminish
with time such that the chance of flurries appears low when the
final wave crosses the area during the afternoon.
Kluber
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...None.
IN...None.
LM...Small Craft Advisory until 9 PM CST Wednesday for the IL
nearshore waters.
Small Craft Advisory until 3 AM CST Thursday for the IN
nearshore waters.
&&
$$
Visit us at weather.gov/chicago
Area Forecast Discussion
National Weather Service Marquette MI
705 PM EST Tue Dec 31 2024
.KEY MESSAGES...
- Lake effect snow showers continue tonight through Wednesday in the
NW wind snow belts. Occasionally heavier snowfall rates up to an
inch per hour will be possible at times especially Wednesday
afternoon and evening (30-40% chance), which may lead to quick
reductions in visibility.
- A Winter Weather Advisory is in effect for Ontonagon, northern
Houghton, Alger, and Luce counties late tonight through Wednesday.
- Temperatures trend down this week with highs a little below normal
for Fri/Sat. Below normal temperatures anticipated for majority of
days next week.
- Accumulating lake effect snow will occur in the west to northwest
wind snow belts from New Year`s Day through this upcoming weekend,
leading to some areas of hazardous travel conditions at times.
- With the colder conditions next week, lake effect snow will
continue on most days, but there are no indications for any winter
storms to impact Upper MI.
- Northwest gales expected Friday and Saturday over central and
eastern Lake Superior.
&&
.SHORT TERM /THROUGH TONIGHT/...
Issued at 239 PM EST Tue Dec 31 2024
Water vapor imagery and RAP analyses show a well-defined midlevel
shortwave/surface low over the Lower Midwest, and weak ridging over
the UP ahead of another shortwave moving over MN. Cooler 850mb air
continues to filter into the UP this afternoon, with plenty of lower-
level lake clouds apparent on satellite. Some mid/upper level cloud
cover is also streaming over the area from the low pressure system
to our south. Radar, webcams, and surface observations show spotty
lake effect snow showers across the NW wind snow belts, though
temperatures in the lower 30s are marginal for anything really
sticking to the ground this afternoon. Expect mainly trace
accumulations in snow showers the rest of the afternoon.
Into tonight, the incoming shortwave will provide a reinforcing shot
of CAA, with temperatures aloft dropping to around -12 to -14C by
the pre-dawn hours of Wednesday. With Superior`s surface
temperatures around 4-6C, increasing moisture in the DGZ and a
slight increase in inversion heights per model soundings, we should
be able to see an increase in coverage of LES across the NW wind
snow belts. SLRs should also increase into the mid/upper teens, with
a couple inches of fluffier accumulations by morning across the snow
belts of the western and eastern UP. With a few more inches of snow
possible throughout the day Wednesday, and a potential for heavier
snowfall rates up to 1in/hr at times, a Winter Weather Advisory will
go into effect for Ontonogan, northern Houghton, Alger, and Luce
counties.
&&
.LONG TERM /WEDNESDAY THROUGH TUESDAY/...
Issued at 345 PM EST Tue Dec 31 2024
The overall weather pattern will be dictated by the consequences of
500mb prolonged troughing over the eastern CONUS supported by
persistent ridging over northeast Canada to southern Greenland. With
cooler and cooler air flowing into the Upper Great Lakes, a
northwesterly-flow LES regime sets up, and while 500mb shortwaves
pivoting around the primary trough over the Ontario/Quebec line will
provide occasional synoptic boosts to the LES, the tracks of large-
scale synoptic low pressure systems will be well to the south of the
UP. A brief interruption to this pattern is possible early next week
as ridging moves over the Upper Great Lakes Monday, but ensemble
support for anomalous troughing over the Appalachians by the middle
of next week is good, bringing some potential for even cooler air to
move over the region. However, run-to-run and intra-ensemble
consistency in the details of cool air is poor, so be wary of
any sources that post maps of single deterministic model runs
showing brutal cold air over the UP.
On New Year`s Day, NW LES bands will be ongoing. While deep
saturated layers are present along with supportive lake-850mb
deltaTs (around -13 C at 850mb to 5 C on the surface of the
lake), inversion heights remain fairly shallow, with soundings
showing only about 3-5kft inversion heights. With little change
in the pattern, the previous forecast of 1-3 to isolated 4 inch
snow accumulations remains for New Year`s Day except over Luce
County, where some localized convergence could elevate snow
totals, with the HREF showing up to 30% chances of snow rates
exceeding 2"/6hr.
Through the remainder of the week, 850mb temperatures will continue
to fall, reaching near -20 C by Friday in some spots. Generally 1 to
4 inch per 12hr snowfall rates are expected, though some higher snow
rates will be seen where localized convergence can be realized. As
the prevailing 925mb wind direction is still highly confident to be
within 30 degrees of 315 (>90% by Friday), long fetch into the
eastern portions of the CWA will support higher amounts in eastern
Alger and Luce counties, though advisory level snowfall is also
expected in typical NW wind snow spots along the western UP shores
of Lake Superior. The SLR might get a bit tricky as conventionally,
cold advection to the extent of what`s expected to end this week
typically plunges the entire convective layer into the DGZ, but
soundings show that the best saturation layer might actually be
above the DGZ, complicating the forecast somewhat. Also, continued
shallow inversion heights will cap the ceiling of snow totals below
winter storm criteria.
Uncertainty grows in the forecast next week as deterministic and
ensembles struggle to agree on the magnitude and timing of ridging
to the west moving over the Upper Great Lakes. From there, multiple
pulses of shortwave troughs plunge southeast from the Canadian
Prairie, ushering in cooler than normal temperatures, though the
LREF only shows about 5% chances of temperatures of 0 or below for
the KSAW area by next Thursday with only around 20% chances for the
rest of the interior west for that period. Looking beyond then,
despite the calls for apocalyptic cold making the rounds on social
media, the probability for more than 1 degree F of anomalous
cold air is only around 50% approaching mid-January per the
Euro ensemble, with probabilities of -10 F or colder only 10% at
any time by the middle of the month in the interior west. With
record low temperatures for this time of year around the -20
mark, it would take a dramatic shift in the models to reflect
record cold potential. However, a Cold Weather Advisory cannot
be entirely ruled out, with the LREF showing chances of wind
chills of -25 or below of around 10% by the 9th.
&&
.AVIATION /00Z TAFS THROUGH 00Z THURSDAY/...
Issued at 705 PM EST Tue Dec 31 2024
Widespread MVFR conditions with periods of IFR at times will prevail
for the duration of the TAF period at all sites. Persistent lake
clouds and lake effect snow showers will hinder improvement. The
exception will be SAW where VFR will be possible by tomorrow
afternoon.
&&
.MARINE...
Issued at 345 PM EST Tue Dec 31 2024
Northwesterly winds will prevail through the first weekend of 2025,
gradually building from sub-20 kt gusts currently to 20-25 kt
overnight tonight, up to 30 kt Thursday night, and then 50-80%
chances of low-end gales by midday Friday. Gale potential continues
through Saturday, with winds falling to near 25 knots for Sunday
before falling to 20-25 kt as winds go more northerly to kick off
next week. Throughout this week, waves build to 3-5 feet by
Wednesday morning, 4-7 feet by Thursday morning, gradually building
to 6-12 feet by Saturday morning (highest near Grand Marais, MI).
Waves then gradually fall below 4 feet by Monday afternoon. Freezing
spray is expected, especially with the gales, with heavy freezing
spray possible in the north-central portions of the lake Friday
night and Saturday morning.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
Upper Michigan...
Winter Weather Advisory from 1 AM to 7 PM EST Wednesday for
MIZ002-003-006-007.
Lake Superior...
None.
Lake Michigan...
None.
&&
$$
SHORT TERM...LC
LONG TERM...GS
AVIATION...TDUD
MARINE...GS
Area Forecast Discussion
National Weather Service Omaha/Valley NE
532 PM CST Tue Dec 31 2024
.KEY MESSAGES...
- A fast-moving storm system will bring upwards of 2-2.5 inches
of snow to parts of the region late Wednesday night through
Thursday morning. Roads could become slippery for the Thursday
morning commute.
- Additional snowfall is possible beginning Saturday and
continuing into Monday morning. There is still considerable
uncertainty with this system, particularly with how far
north/south it will track.
- Confidence is high in temperatures trending significantly
colder from Friday into early next week. Wind chills on Monday
and Tuesday mornings may drop into the -15 to -20 degree
range, especially in northeast Nebraska and west-central Iowa.
&&
.DISCUSSION...
Issued at 306 PM CST Tue Dec 31 2024
Tonight and Wednesday...
A vorticity lobe presently extending from northwest MN into
eastern Dakotas will pivot southeast through the area tonight.
Ahead of that disturbance, latest HRRR output indicates weak
simulated-reflectivity swaths spreading southeast through far
eastern NE and western IA tonight within the zone of associated
height falls/forcing for ascent. Proximity forecast soundings
indicate a small amount of positive buoyancy at the top of the
boundary layer, suggestive of some snow shower potential. For
now, the forecast will indicate flurries for tonight in those
areas as the potential for measurable precipitation appears to
be less than 20%.
On Wednesday, a surface ridge will build through the mid MO
Valley with decreasing clouds and slightly warmer temperatures
with highs in the 30s.
Wednesday night and Thursday...
The 12z models remain on track in progressing a low-amplitude
shortwave trough through the region in tandem with a surface low
and cold front. Latest projections indicate snowfall onset by
12 AM Thursday in northeast NE with that precipitation shield
expanding southeast across much of the area through the pre-dawn
hours, prior to ending from west-to-east during the day on
Thursday. There`s a fairly robust frontogenesis signal near and
to the north of the surface low track, where a corridor of
higher snowfall rates is possible. This forecast update will
indicate slightly higher snow totals of 2-2.5" in that zone from
Hartington southeast through Harlan, IA with amounts decreasing
with southwestward extent. The snowfall will occur during the
Thursday morning commute for many, and slippery roads could
extend that travel time.
Highs on Thursday are expected to range from the mid 20s near
the SD border to the mid 30s across the southern part of our
area.
Friday through Monday...
The primary feature of interest this period is a prominent
shortwave trough, which is forecast to emerge from the Rockies
into the central and southern Plains Saturday night into Sunday.
The models have come into better agreement in the track and
timing of the midlevel system. However, there is still
considerable ensemble spread in the track of the associated
surface low. A more northern low track would result in greater
accumulating snowfall potential for our area, whereas a more
southern track would result in less.
Current indications are that warm-advection-related snow could
develop across portions of northeast NE on Saturday (20% PoPs)
with increasing snow chances areawide Saturday night into Sunday
night. Peak PoPs of 50-70% on Sunday are largely dependent on
the northern fringe of the deformation precipitation shield
(located to the north of the surface low) overlapping our area.
Given the uncertainties in where the deformation axis will
setup, confidence in snowfall amounts for our area remains low.
What we are confident in is much colder temperatures beginning
Friday and continuing through at least early next week. An
initial surge of colder air is expected on Friday when highs
will range from the teens near the SD border to around 30 along
the KS border. Temperatures subsequently trend colder through
the weekend into early next week as an Arctic air mass is drawn
into the region by the above-mentioned surface low passing to
our south. Coldest highs of 11 to 18 are forecast on Monday
with minimum wind chills approaching -15 to -20 on Monday and
Tuesday mornings.
&&
.AVIATION /00Z TAFS THROUGH 00Z THURSDAY/...
Issued at 530 PM CST Tue Dec 31 2024
Overcast MVFR ceilings across the entire area are forecast to
slowly lift through the evening hours and should reach VFR
category before midnight. By daybreak, skies should be mostly
clear. Light westerly winds will become southwesterly over the
next 24 hours.
&&
.OAX WATCHES/WARNINGS/ADVISORIES...
NE...None.
IA...None.
&&
$$
DISCUSSION...Mead
AVIATION...Nicolaisen
Area Forecast Discussion
National Weather Service Tulsa OK
700 PM CST Tue Dec 31 2024
...New UPDATE...
.KEY MESSAGES...
Updated at 200 PM CST Tue Dec 31 2024
- Near normal temps through the rest of the week
- Reinforcing cold front moves through Thursday night into Friday
keeping temperatures near to slightly below normal into the weekend
- Weekend storm system brings low to medium (20-60%) rain chances
late Saturday night into Sunday. Potential for wintry precipitation
Sunday night as system departs. Uncertainty remains high with this
system.
- Much colder air spills into area early next week.
&&
.UPDATE...
Issued at 700 PM CST Tue Dec 31 2024
Stubborn low cloudiness looks to persist for a good portion of the
night before starting to scatter toward morning, but confidence in
this scenario is lower than usual. CONSShort, essentially a blend
of short-term models, and the HRRR are handling the low clouds
better than the traditional model blend. Updated low temp forecast
using CONSShort forecast, resulting in a slight upward adjustment.
Lacy
&&
.SHORT TERM...
(Through Tonight)
Issued at 200 PM CST Tue Dec 31 2024
Northerly winds will gradually calm this afternoon and evening
across the region as surface high pressure settles over the area
tonight. This will allow for temperatures to drop into the 20s for
most locations north of I-40 tonight, with low 30s expected south
of I-40. So, bundle up if heading out to celebrate the new year
this evening. Cloud cover will likely linger across portions of
northwest Arkansas this evening and overnight, but an otherwise
uneventful night is in store to ring in 2025.
Bowlan
&&
.LONG TERM...
(Wednesday through Tuesday)
Issued at 200 PM CST Tue Dec 31 2024
Mostly benign conditions with near normal temperatures are
expected through the rest of the work week as surface ridging
remains in the area through Thursday. Another cold front is due to
move through Thursday night into Friday, reinforcing the cooler
airmass in place and keeping temperatures near to slightly below
normal into the weekend.
Attention for this forecast will mainly focus on the system set to
affect the area this weekend. Guidance seems to be settling in a
bit more on potential impacts to our area, but much uncertainty
still remains as often does with winter systems in the region.
There seems to be a pretty good consensus on the upper air
pattern, with a compact shortwave trough ejecting out of the
Southern Rockies on Saturday and moving across the Plains during
the day Sunday. Where the uncertainty exists is in the various
solutions for the surface pattern. The ejecting trough will
trigger surface cyclogenesis over the High Plains during the day
Saturday. The track of this surface low will be the key player in
what type of weather we see across eastern Oklahoma and northwest
Arkansas on Sunday.
In response to the deepening cyclone, southerly surface winds
should increase during the day Saturday and act to bring a warm
front back north through eastern Oklahoma Saturday afternoon. Most
guidance is consistent in this, though the GFS/GEFS keeps the
warm front south of the area Saturday with a much more southerly
track for the surface low across northern Texas, keeping highs in
the 30s throughout the day. This forecast will continue to lean
toward the bulk of the guidance with the warm front coming north
and highs climbing into the upper 40s to mid 50s across the
region Saturday into Sunday. Precipitation chances will then
increase Saturday night into Sunday as the mid level wave moves
out into the Plains. Leaning toward a more northerly track in the
surface low would mean this precipitation would be all liquid with
the whole forecast area within the warm sector south of the warm
front. At least some limited instability will be present in the
warm sector Sunday morning and afternoon and a time for
thunderstorms will be possible for the area. Depending on the
timing of the cold front, some of these storms could be strong to
severe as shear increases with the approaching shortwave. Current
timing would see better severe chances mostly east and south of
the area, but a slower front into Sunday afternoon could allow
enough destabilization that a few strong to severe storms would be
possible ahead of the front. The cold front will usher in a much
colder polar airmass in its wake and wintry precipitation will be
possible as the system departs. Model profiles mostly show a quick
transition to snow with some freezing rain for a time Sunday
night. Again, there is still a lot of uncertainty in track and
timing with some solutions possibly having much more winter
impacts. Continue to check back for updates as we monitor the
trends and guidance come into better agreement.
Much colder air will linger into next week as Canadian high
pressure remains planted over the region.
Bowlan
&&
.AVIATION...
(00Z TAFS)
Issued at 512 PM CST Tue Dec 31 2024
Widespread low clouds persist through a large portion of eastern
OK and northwest AR this evening. Ceilings across OK and at KFSM
should remain just above 3 KFT, but may occasionally dip below at
NE OK sites before clouds begin to scatter later this evening.
Clouds expected to be much slower to move out of NW AR, likely
maintaining MVFR ceilings into early Wednesday morning at least.
All areas will see light winds and a few mid/high clouds for the
majority of Wednesday.
&&
.PRELIMINARY POINT TEMPS/POPS...
TUL 30 46 31 52 / 0 0 0 0
FSM 32 50 32 54 / 0 0 0 0
MLC 30 49 32 55 / 0 0 0 0
BVO 26 45 27 52 / 0 0 0 0
FYV 28 46 29 52 / 0 0 0 0
BYV 28 43 31 49 / 0 0 0 0
MKO 30 46 31 52 / 0 0 0 0
MIO 28 43 30 48 / 0 0 0 10
F10 29 46 31 54 / 0 0 0 0
HHW 33 50 33 55 / 0 0 0 0
&&
.TSA WATCHES/WARNINGS/ADVISORIES...
OK...None.
AR...None.
&&
$$
SHORT TERM...04
LONG TERM....04
AVIATION...14