Forecast Discussions mentioning any of
"HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 12/31/23
Area Forecast Discussion
National Weather Service Denver/Boulder CO
733 PM MST Sat Dec 30 2023
.KEY MESSAGES...
- Scattered light snow showers across the central mountains on
Sunday, with minimal accumulation expected
- Active jet stream towards the end of the period, but do we get
the moisture and lift this far north?
&&
.UPDATE...
Issued at 732 PM MST Sat Dec 30 2023
Main concern for late tonight will be fog development over the far
nern plains. HRRR has been rather consistent in showing areas of
fog between 11z and 16z over Logan, Phillips and Sedgwick counties.
Could see visibility 1/4 mile or less in some places as well.
Otherwise, little change needed to previous fcst at this time.
&&
.SHORT TERM...(This evening through Sunday)
Issued at 117 PM MST Sat Dec 30 2023
Temperatures across the urban corridor have warmed nicely today,
with temperatures generally sitting in the mid 50s. Other than a
few patches of high cloud cover, most of the county warning area
is sitting with clear blue skies this afternoon.
We`ll have another mostly clear night tonight. With increasing
high cloud cover, temperatures should be warmer (but still in the
single digits/near zero) across the typical mountain valley cold
spots. Some patchy fog is also possible over far northeastern
Colorado late tonight into Sunday morning.
The mild, sunny weather will come to an end on Sunday, as a very
weak trough attempts to push into the region late tonight into
tomorrow. By tomorrow afternoon the trough is so poorly organized
that I feel generous even calling it a trough. Nonetheless, there
will be cooler temperatures and a modest increase in moisture
aloft, leading to gloomy but mostly dry forecast. Some light snow
showers are still possible in the high country, generally along
and south of I-70. Less than an inch of snow is forecast.
.LONG TERM...(Sunday night through Saturday)
Issued at 117 PM MST Sat Dec 30 2023
New Years Day - Friday...Just a quiet stretch of weather overall
with near average temperatures for early January. A few periods of
high country snow showers possible, 20-30% chances, Tuesday and then
Thursday into Friday, otherwise dry. Long range ensembles show the
southern jet stream getting more active towards the tail end of the
long term period with larger waves moving by to our south. Question
is can we drag these systems back towards the north?
&&
.AVIATION...(For the 00Z TAFS through 00Z Sunday evening)
Issued at 440 PM MST Sat Dec 30 2023
Only concern is possibility of fog in the 12z-15z time period on
Sun. HRRR has been trying to develop fog over southern Weld county
late tonight although it keeps it north of DIA. With large T-TD
spreads not very confident that this will occur but have included
a VCFG just in case. Otherwise VFR conditions thru the period.
Winds will become SSE by 02z and then more SW by 07z. By 12z they
may have a light WNW component and then shift to light north by
18z.
&&
.BOU WATCHES/WARNINGS/ADVISORIES...
None.
&&
$$
UPDATE...RPK
SHORT TERM...Hiris
LONG TERM...Heavener
AVIATION...RPK
Area Forecast Discussion
National Weather Service Billings MT
745 PM MST Sat Dec 30 2023
.UPDATE...
Satellite imagery shows a sharp ridge axis over east-central MT
with clear skies over our east and high clouds in the west. Temps
are already approaching forecast lows at some locations so have
made some adjustments to tonight`s min temps (per clear skies and
light winds). There is an area of stratus advecting westward thru
ND (close to Dickinson at 0230z), and recent HRRR runs have
suggested fog along our far eastern border beginning around 09z
tonight...and this seems reasonable. Have added patchy fog to
Baker-Ekalaka-Alzada from 09-18z. Otherwise it will be another
quiet weather night. JKL
&&
.DISCUSSION...
Tonight through Sunday Night...
An amplified upper ridge stretched from New Mexico northward into
southern Canada and was providing abundant sunshine across
Montana this afternoon. Surface high pressure was sliding
southeast into southern Saskatchewan and providing light winds.
These winds will turn east to southeast late this afternoon
(especially over eastern zones). These low level winds will turn
westerly by Sunday night as a surface trough swings through ahead
of a weak cold front for Monday. The upper ridge will get
flattened and pushed east into the Dakotas Sunday night as a
shortwave drives across Montana. This wave will come through dry
Sunday night as the strongest energy stays north. Winds may
briefly pick up from Nye to Big Timber to Livingston Sunday night,
but nothing significant, with possibly some gusts to 30 mph
there. Otherwise, temperatures will remain above seasonal with
highs on Sunday in the 40s and lows tonight and Sunday night in
the 20s (with teens east). TWH
Monday through Friday...
On Monday, a passing short wave to the north will push a cold
front across the region, bringing a 15-25% chance of
precipitation to the mountains and a 15% or less chance to lower
elevations. Then, ridging is expected to set up for Tuesday and
Wednesday, bringing dry conditions. Thursday, upper level split
flow will move over the region, bringing another low (15% or less)
chance of precip before weak ridging moves in Friday.
Currently, there is uncertainty between the models. The first
scenario has ridging continue into the weekend and keep
conditions dry. The second scenario is a Pacific trough
approaching and bringing cooler and wetter conditions and
increased precip chances as early as Friday evening. Due to this
uncertainty, there is currently a 20-30% chance of precip over the
western mountains and foothills Friday evening through overnight.
High temperatures over the east will be in the mid 30s to low 40s
and generally in the 40s for the rest of the region. Archer
&&
.AVIATION...
Expect VFR tonight and Sunday with clear skies or high clouds
along with light winds. Localized fog or stratus in far southeast
MT may produce MVFR or lower conditions near KBHK-K97M between
09-18z...but confidence remains low at this time. JKL
&&
.PRELIMINARY POINT TEMP/POPS...
Sun Mon Tue Wed Thu Fri Sat
-----------------------------------------------------------
BIL 024/044 029/046 025/044 024/041 025/044 025/045 028/045
00/B 01/B 10/B 00/B 01/B 01/U 11/B
LVM 030/048 028/043 023/043 023/043 024/043 025/044 027/040
00/B 01/U 00/U 00/B 01/U 01/B 22/S
HDN 018/043 023/046 020/044 018/042 019/044 019/045 022/047
00/B 01/B 10/B 00/B 01/B 11/U 11/B
MLS 015/040 021/041 022/039 018/036 020/038 018/040 021/041
00/U 01/B 10/B 00/B 00/B 00/U 11/B
4BQ 018/044 023/045 023/043 021/040 021/041 021/044 022/044
00/U 00/B 10/B 00/B 00/B 00/U 01/B
BHK 012/037 017/040 019/035 015/036 016/038 014/041 017/038
00/U 00/B 10/B 00/B 00/B 00/U 01/B
SHR 020/046 025/046 019/044 019/043 019/043 018/046 021/045
00/B 01/B 10/U 00/B 01/U 10/U 11/B
&&
.BYZ WATCHES/WARNINGS/ADVISORIES...
MT...None.
WY...None.
&&
$$
weather.gov/billings
Area Forecast Discussion
National Weather Service Goodland KS
238 PM MST Sat Dec 30 2023
.SHORT TERM...(This evening through Monday Night)
Issued at 145 PM MST Sat Dec 30 2023
At the beginning of the short term period, the latest RAP analysis
shows the CWA having a northwesterly flow aloft being underneath the
forward portion of an upper air ridge to the west on Saturday
afternoon. Current satellite imagery and surface observations report
dry conditions and mostly sunny skies across the CWA with snow still
seen on the ground generally from areas along and north of a line
from Cheyenne Wells, CO to Colby, KS. Going through the rest of
today, models have CWA taking a bit more of a west-northwesterly
flow aloft overnight with the ridge advancing close to the CWA in
the west. At the surface, the afternoon cold front expects to have
made it through the CWA by the evening hours with dry conditions
expected throughout the rest of the day. There also looks to be a
concern for some patchy fog along the CO border which may lower
visibilities a bit. Will monitor this going forward, but not
enough confidence in low enough visibilities for a fog highlight
at this time. Overnight lows for tonight look to be in the middle
teens to lower 20s.
On New Year`s Eve, forecast guidance forecasts the western ridge
continuing its influence on the upper air pattern over the CWA with
the axis of the ridge progressing to just west of the CWA by the
overnight hours. At the surface, models have a surface high moving
down from the Northern Plains throughout the day and into the CWA
by the overnight hours while dry conditions persist for another
day. Models are also showing the potential for some patchy fog
around midnight in the northeastern quadrant. Daytime high
temperatures for Sunday look to cool to between the lower 30s and
the lower 40s with overnight lows in the middle to upper teens.
For New Year`s Day, models depict the axis of upper air ridge moving
over the CWA by midday with an upper air low developing over the
southwestern CONUS late in the day. At the surface, the CWA expects
surface winds to shift to a southerly direction early in the day
with the aforementioned surface high moving southeast towards the
KS/MO/OK border area by the evening hours. Precipitation chances
expect to remain minimal on New Year`s Day for the CWA as a
result of this setup. Daytime high temperatures for the first day
of 2024 look to range between the upper 30s and upper 40s
followed by overnight lows in the lower 20s.
.LONG TERM...(Tuesday through Saturday)
Issued at 1219 PM MST Sat Dec 30 2023
Split upper level flow will present to start the extended period. A
surface high will nudge its way across eastern portions of the area
in response to a system across the upper Great Lakes. The main focus
for the period continue to be on a trough across the SW CONUS
towards the latter part of the first week of the new year. GFS and
ECMWF have flipped solutions from 24 hours ago with the ECMWF now
bringing the system south and the GFS further north, so will
continue to ride with ensemble guidance for this system. GEFS and
EPS both support at least light qpf mainly along and south of
Interstate 70. Light snow and rain/snow mix is currently favored.
GEFS ensemble members are bit more on board with snowfall
occurring which raises my confidence in this occurring. The one
change that GFS is showing compared to yesterday is that the
system is bit more organized rather as it turns into a closed low
across eastern Kansas than being an open wave vs what was seen
yesterday. A more organized system would favor accumulating snow.
Overall confidence in accumulating snow occurring across the
region is currently around 25- 30%) After the late week system,
weak ridging develops through next weekend before another trough,
potentially stronger moves towards the Plains.
Temperatures for the period, continue to remain forecasted near
normal with highs in the 40s and lows in the mid teens to low 20s.
The exception currently appears to be Friday as the system is moving
across the area where temperatures are forecasted in the 30s to
low 40s. Depending on the overall track of the system, this may be
to high as the more aggressive, better organized system with the
GFS show 850mb temperatures on the colder wraparound portion
around -2 to -4C which would would make it difficult for
temperatures to make it out of the 20s where precipitation would
be falling.
&&
.AVIATION...(For the 00Z TAFS through 00Z Sunday evening)
Issued at 224 PM MST Sat Dec 30 2023
KGLD...VFR conditions look to begin the 00Z TAF period with
variable winds around 6 kts. At 14Z, MVFR visibilities come to
KGLD with some fog developing around the CO border. Visibilities
look to improve back to VFR conditions by 16Z with fog lifting
going as the variable winds around 6 kts continue through the end
of the period.
KMCK...VFR conditions are also seen to start the 00Z TAF period
with variable winds around 6 kts. By 12Z, KMCK sees an overcast
cloud deck developing around 700 ft beginning IFR conditions for
the terminal. VFR conditions look to return to KMCK at 16Z as the
cloud cover looks to decrease a bit.
Will continue to monitor future model runs in case visibilities
look to worsen in the morning and amend TAFs if needed.
&&
.GLD WATCHES/WARNINGS/ADVISORIES...
KS...NONE.
CO...NONE.
NE...NONE.
&&
$$
SHORT TERM...076
LONG TERM...Trigg
AVIATION...076
Area Forecast Discussion
National Weather Service Grand Rapids MI
647 PM EST Sat Dec 30 2023
LATEST UPDATE...
Aviation
.SHORT TERM...(This evening through Sunday night)
Issued at 228 PM EST Sat Dec 30 2023
- Could see local impacts into New Years Eve
To start, drizzle will likely be developing tonight as a moist
southwest flow strengthens. The most favored region is near and
west of US-131 where temperatures are expected to remain just
above freezing. However inland and further north, there could be a
several hour period where if it did drizzle, temperatures may
support some of it to freeze. POPs are lowest in those areas so
confidence on impacts happening remain low. However we will need
to monitor trends through the evening. If the current clearing
north of a Muskegon to Grand Rapids line lingers into the evening,
temperatures could end up a few degrees colder and support an
increased potential for freezing drizzle and associated impacts.
The mid level low over northern MN and its associated surface wave
tracks through MI Sunday afternoon and evening. The moisture
deepens up through the DGZ later in the morning and persists into
the early evening. Overall the lift looks weak but the mid level
lapse rates do become steep. Thus any remaining drizzle/freezing
drizzle will transition into mainly snow showers. Looking at the
ensemble forecasts, the ECMWF backed off on the qpf and trended
several degrees higher, which would reduce the impact risk for
much of the CWA. The Canadian also trended slightly higher with
the temperatures Sunday into Sunday evening. Ensemble forecast max
temperatures support values mostly in the 35 to 37 degree range,
which reduces the daytime impact risk. It`s mainly early in the
day and during the evening hours, when temperatures may be around
freezing that we will have to monitor. Early the day, any qpf
should be limited given the shallow nature of the
moisture(unsaturated DGZ). Then during the evening, the event
will be winding down, so it`s unclear how much qpf we will see
then.
In summary, no headlines will be issued with this forecast. We
will generally feature only local areas with trace amounts of
freezing rain/drizzle. As for the snow, an inch or less is
favored.
.LONG TERM...(Monday through Saturday)
Issued at 228 PM EST Sat Dec 30 2023
-A Few Lake Effect Showers Monday Morning
Behind the departing surface low, 850 mb temperatures fall into
the -8C vicinity Sunday night into Monday morning. As a result, a
few lake effect snow showers are possible into Monday morning
near the lakeshore given the north-northwest flow pattern. Upper-
level ridging and the influence of a surface high south of the
state providing subsidence, as well, as the initiation of warm air
advection, end any lake effect by mid day. Dry weather then
prevails into Tuesday with breezy conditions Tuesday afternoon as
a 30-35 knot low level jet moves overhead. Both NBM 25th-75th
percentile ranges and ECMWF ensemble wind gust forecasts suggest
gusts in the vicinity of 30 mph is the favored scenario. Warm air
advection will support highs near 40 Tuesday.
-Lake Effect Show Showers Wednesday
The next chance of precipitation after Monday occurs Wednesday.
A cold front is forecast to move across lower Michigan Tuesday Night
into Wednesday morning. Behind this front 850 mb temperatures
fall to around -12C supporting a period of lake effect snow
showers. Given the progressive nature of the trough, and surface
ridging moving in by Wednesday night, any snow would be brief.
Combined with the currently shallow forecasted moisture profile,
as GFS forecast soundings keep moisture depth under 5000 ft, any
accumulation would be light. The favored location for any
accumulations is presently northwest flow lake effect belt areas
west of US131.
-Dry Weather Into the Weekend
Behind the lake effect, 500 mb heights rise as we transition into
zonal flow, and lower Michigan comes under the influence of
surface ridging. The sensible effect of this is going to be dry
weather for lower Michigan Thursday into Saturday. As 850 mb
temperatures warm back towards 0C, surface temperatures look to
warm to slightly above normal in the upper 30s.
&&
.AVIATION...(For the 00Z TAFS through 00Z Sunday evening)
Issued at 640 PM EST Sat Dec 30 2023
No significant changes from previous thinking. MVFR conditions at
the start of the period should turn IFR as ceilings lower. -DZ
remains a possibility overnight especially for MKG/GRR/AZO/BTL.
The 18z HRRR does show some pockets of drizzle developing in those
areas mainly after 03z. Expecting steadier showers mixed with snow
to move in mid morning and likely peak during the early to mid
afternoon hours. A changeover to all snow is possible during the
peak of the event but with marginal temperatures it is
questionable how impactful this will be, other than reductions to
visibility. IFR is expected to dominate most of this TAF period.
&&
.MARINE...
Issued at 228 PM EST Sat Dec 30 2023
As the low pressure system tracks east southeastward through the
zones we will see east winds backing to the north Sunday into
Sunday night. The combination of cold air advection and
strengthening winds will likely allow for hazardous conditions for
small craft to develop by Sunday evening. We will feature the
hazardous conditions developing in the nearshore forecast. We may
need headlines if the future forecasts continue to support this
scenario.
&&
.GRR WATCHES/WARNINGS/ADVISORIES...
MI...None.
LM...None.
&&
$$
SHORT TERM...MJS
LONG TERM...Thomas
AVIATION...Hoving
MARINE...MJS
Area Forecast Discussion
National Weather Service Chicago/Romeoville, IL
846 PM CST Sat Dec 30 2023
.UPDATE...
Issued at 846 PM CST Sat Dec 30 2023
Based on upstream trends and forecast soundings, have opted to
hit the freezing drizzle potential harder and hoist a winter
weather advisory for the entire CWA until noon Sunday for the
expected freezing drizzle. Through the evening there have been
multiple AWOS/ASOS reports suggesting freezing drizzle with MN DOT
website continuing to show numerous accidents due to FZDZ.
Forecasting FZDZ is VERY challenging and requires a rather narrow
spectrum of parameters, any of which falling outside of
acceptable range would dramatically lessen the FZDZ threat.
Having said that, forecast soundings across the CWA late tonight
into Sunday morning show deepening low level saturated layer
(translating to a thickening stratus deck). Satellite trends
support these trends noted in forecast soundings.
Episodic bursts of upward vertical motion within that stratus
deck and combined with 15-25kt of vertical wind shear within the
cloud bearing layer would suggest collision and coalescence
sufficient to continue to support FZDZ as the system spreads
southeast into our CWA tonight.
Forecast soundings suggest cloud top temps will vary between -10
and -15C late tonight into Sunday morning. At -12C, there`s about
a 70% chance of ice nuclei being present in a stratus deck of
continental origins like this one. When ice nuclei is present,
precip type would transition over to a very fine snow grain and
end the threat of ice accretion at the surface. Upstream cloud top
temps are between -12C and -15C, however there have been freezing
drizzle reports with cloud temps as warm as about -13.5C upstream.
All of this says that it isn`t terribly clear with what frequency
this deck will have ice nuclei present once it arrives. After
initially starting as FRDZ, it is possible that p-type could
oscillate between FZDZ and freezing snizzle (very fine light snow
or flurries mixed with FZDZ) Sunday morning.
Chances for ice accretion/FZDZ range from about 70% NW CWA to
about 40-50% across northwest IN. This is certainly lower
confidence than would typically warrant a winter wx advisory, but
given the greater risk for higher impacts with FRDZ, and upstream
conditions, felt the best course of action was a preemptive winter
wx advisory to provide a heads up, especially to DOTs.
Temps across most of the CWA should rise to or just above freezing
by noon Sunday, likely ending the freezing drizzle threat with
drizzle or snizzle (drizzle/snow mix) probably continuing into the
afternoon. Surface and upper trough axis is forecast to move
across the CWA early Sunday evening, which could lead to deeper
saturation/ascent and perhaps some most robust snow showers,
especially eastern CWA. Temps will be marginal, but could be close
enough to freezing to allow for some minor accums (1" or less),
mainly elevated/grassy surfaces. No changes made to that part of
the forecast, will punt that to the oncoming overnight shift to
access.
- Izzi
&&
.SHORT TERM...
Issued at 316 PM CST Sat Dec 30 2023
Through Sunday night...
Key messages:
* Periods of light snow, snow showers, and flurries are likely on
Sunday/New Year`s Eve. The best chances (50-70%) for minor snow
accumulations (dusting to an inch) are expected roughly along and
north of a Rochelle, IL to Rensselaer, IN line.
* Lake effect snow showers are expected to linger Sunday night into
Monday morning, primarily into portions of northwest Indiana where
a 50-70% chance for additional snow accumulations up to an inch or
two exists.
* There is about a 20% chance that a brief period of drizzle or
freezing drizzle occurs prior to the onset of snow tonight, with
the best chances for freezing drizzle being in interior northern
Illinois.
Some of this morning`s residual stratus continues to enshroud the
area this afternoon, holding down temperatures below 40 degrees in
areas that have not seen much of the Sun today. Meanwhile, looking
upstream into the Upper Mississippi River Valley, a considerably
more expansive blanket of post-frontal stratus has been making good
southeastward progress and will eventually reach our forecast area
as a surface low (analyzed in northern Wisconsin at press time)
continues its trek towards the Lower Peninsula of Michigan.
Overall, our going forecast remains on track, but one small change
with this forecast package was to add a slight chance mention of
drizzle/freezing drizzle tonight for a brief period right at the
onset of our mentionable PoPs. Forecast soundings indicate that
stratus depths will grow upwards as inversion heights rise in the
cold air advection regime behind tonight`s cold frontal passage,
reaching 3000-4000 ft depths before adequate quantities of ice
nuclei are introduced into the cloud deck. These forecast profiles
look quite similar to the 0-hour HRRR soundings from earlier HRRR
runs when freezing drizzle was ongoing in northeastern Minnesota and
northern Wisconsin earlier this morning, albeit in a location that
was much closer to the center of the surface low. Nevertheless,
would not be surprised to see some drizzle here at the onset of
precipitation tonight, so erring on the side of caution, have
introduced a slight chance mention of drizzle and/or freezing
drizzle to the forecast grids for a 1-3 hour period at most
locations in our forecast area. Surface temperatures are most likely
to be below freezing at the onset of precipitation in interior
northern Illinois, so that is where freezing drizzle would be
favored over drizzle, though surface temperatures will be close
enough to freezing across the CWA, so can`t truly rule out freezing
drizzle occurring anywhere with the exception of maybe the
locations within the footprint of the Chicago metro urban heat
island.
Once cloud tops reach the -10C level and heterogeneous nucleation
permits the production of snowflakes, snow should become the
dominant precipitation type and remain that way through the
remainder of the day on Sunday. Subpar moisture quality and
steepening mid-level lapse rates suggest that the snow should take
on a showery character at times, particularly across the
northeastern half of our CWA, which will be positioned closer to the
core of the large scale forcing for ascent. Locations in the
southwestern half of our CWA are less likely to get in on the more
robust snow showers, and may ultimately only see flurries over the
course of the day. On the whole though, snow accumulations should
remain minimal across our forecast area through sunset with the
limited moisture availability, generally poor snow quality, marginal
surface temperatures, and the expected limited residence time of any
more robust snow showers all playing a role in likely keeping snow
accumulations under an inch through the daytime hours.
Sunday night into Monday morning, lake effect parameters should
improve modestly as convergence over Lake Michigan enhances
(possibly in response to the development of a mesolow) and the
fetch over the lake lengthens as surface winds turn more northerly.
As a result, lake effect snow showers (possibly mixed with rain in
the immediate vicinity of the still relatively mild lake) are
expected to continue into the beginning of the new year, primarily
into portions of northwest Indiana, though slight fluctuations in
the prevailing wind directions over the lake could steer the lake
effect precipitation into portions of far eastern Illinois for a
time as well. While the aforementioned mild marine layer and
potential loss of cloud ice at times could result in rain or drizzle
taking a slice of the QPF pie away from snow, the residence times of
any lake shower bands could still end up being long enough to
produce up to an inch or two of snow accumulation in northwest
Indiana when all is said and done. This could lead to some slippery
travel for those returning home from New Year`s festivities, so be
mindful of this if you have any plans for the New Year.
Ogorek
&&
.LONG TERM...
Issued at 316 PM CST Sat Dec 30 2023
Monday through Saturday...
Key Messages:
* Chance (30-50%) for lake effect snow showers across parts of NW
Indiana Wednesday night/Thursday morning.
Any lingering lake effect precipitation across northwest Indiana
will come to an end through Monday morning as a subsidence
inversion builds downwards. With high pressure readily building
across the region, seems like we`ll manage to scour lingering
stratus out (away from the lake at least), netting a mostly
sunny/partly cloudy day with seasonable temperatures in the low to
mid 30s.
A pair of fast-moving shortwaves will traverse the region on
Tuesday and will additionally shuttle a cold front through our
forecast area through the evening. With little moisture to work
with, expecting this to by a dry frontal passage at this time.
Otherwise, looking at some southwesterly breezes developing
through Tuesday as mixing deepens into a relatively stout low-
level jet max. A robust subsidence inversion centered near 800 mb
looks like it`ll probably curtail deeper mixing pretty
effectively, however. Have capped gusts in the mid/upper 20 mph
range for the time being as a result.
Slightly deeper saturation into the base of the dendritic growth
zone on Wednesday may yield at least a small chance for some
flurries/light snow showers across northern Illinois although not
a strong enough signal to warrant PoPs or a weather mention at
this point. As colder air spills in from the north and northwest
through Wednesday night, expecting to see an increase in lake
effect snow showers focusing into parts of northwest Indiana. Lake
induced ELs look like they peak around 7 kft during this
timeframe, with 850-lake temp differentials around 15 C. This
could support a brief period of more organized/robust snow
showers, particularly into Porter County given winds from a 320 -
350 direction.
After a brief shot of cooler air on Thursday, southerly return
flow will yield slightly warmer conditions Friday and Saturday.
Carlaw
&&
.AVIATION...
For the 00Z TAFs...
550 PM...Forecast concerns include...
Freezing drizzle overnight.
Light snow/shower showers Sunday.
A period of possible moderate snow near the lake Sunday evening.
Gusty northerly winds Sunday afternoon/evening.
An area of freezing drizzle continues to expand across western WI,
southeast MN and northern IA early this evening. Much of the model
guidance suggests this will continue moving southeast into
northern IL overnight ahead of a cold front, eventually becoming
light snow or snow showers. Current forecast for RFD/DPA for a few
hours of freezing drizzle looks on track. This may need to be
expanded into ORD/MDW/GYY with later forecasts. Current
uncertainty is whether temperatures will drop below freezing in
the more urban area of ORD/MDW.
Light snow or snow showers will continue into Sunday morning with
perhaps a period of light snow Sunday afternoon. Vis/cigs during
this time will likely be on the edge of low mvfr and ifr.
Another frontal boundary will move across the area late Sunday
afternoon or early Sunday evening, shifting winds northerly with
gusts increasing into the lower 20 kt range. Its during this time
period where a band of possibly moderate snow may move across ORD/
MDW and GYY. There still remains uncertainty, but worthy of prob
mention from this distance for ifr cigs/vis and this may be too
optimistic if a band of moderate snow does indeed move across the
area.
A short break in the mvfr cigs is possible this evening, between
the current area of mvfr cigs and another area behind the front,
but mvfr cigs are expected through the period. Some patchy fog
will be possible this evening, especially if the clearing
persists. cms
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...Winter Weather Advisory...ILZ003-ILZ004-ILZ005-ILZ008-ILZ010-
ILZ011 until noon Sunday.
Winter Weather Advisory...ILZ006-ILZ012-ILZ013-ILZ019-ILZ020-
ILZ021-ILZ103-ILZ106-ILZ107...2 AM Sunday to noon Sunday.
Winter Weather Advisory...ILZ023-ILZ032-ILZ033-ILZ039-ILZ104-
ILZ105-ILZ108...4 AM Sunday to noon Sunday.
IN...Winter Weather Advisory...INZ001-INZ002-INZ010-INZ011-INZ019...4
AM Sunday to noon Sunday.
LM...Small Craft Advisory...IL and IN nearshore waters...6 PM Sunday
to 9 AM Monday.
&&
$$
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Area Forecast Discussion
National Weather Service Twin Cities/Chanhassen MN
909 PM CST Sat Dec 30 2023
.KEY MESSAGES...
- Quick round of wintry weather this afternoon through early
Sunday, with freezing drizzle and light snow. Accumulations
generally under one inch expected. Slick travel conditions may
develop.
- Record warmest December likely at all 3 climate sites, more
information in the climate section below.
&&
.UPDATE...
Issued at 905 PM CST Sat Dec 30 2023
Areawide freezing drizzle persisted long enough to deteriorate road
conditions ahead of the line of snow this evening, especially along
and east of the I-35 corridor. In collaboration with neighboring
offices, a Special Weather Statement and a Winter Weather Advisory
had been issued across central and eastern MN, as well as western
WI. The main concern was the areas of ice forming along roadways
leading to multiple accidents. As freezing drizzle transitions to
snow in central and eastern MN, we are seeing conditions improve and
return back on track to forecast. As this line pushes further south
and east, conditions are expected to improve across southern MN and
Western WI as well. Thus, the Winter Weather Advisory is scheduled
to expire at midnight unless there are any major changes to the
forecast.
&&
.DISCUSSION...
Issued at 140 PM CST Sat Dec 30 2023
Forecast appears to be on track early this afternoon, as an incoming
round of wintry weather will bring cosmetic snow to the region later
this evening. The only major amendment to the forecast was to
increase the mention of freezing drizzle areawide from this
afternoon through early evening. Ground observations across central
and northern Minnesota have reflected freezing drizzle as the
precipitation type, which is supported by a lack of ice/saturation
in the DGZ noted on RAP forecast soundings. Early afternoon regional
radar captures widespread echoes across northern Minnesota, which
are forecast follow a surface low to the southeast through tonight.
The arrival of precipitation will be supported by moderate omega
forcing, and as a result deeper saturation. Soundings depict a
saturated DGZ by this evening, which will support snowfall as the
dominate precipitation type for the remainder of the event. As far
as snowfall expectations, this remains as high PoP/low QPF scenario,
as Grand Ensemble/WPC QPF register a few hundredths of liquid
precipitation. Locations in eastern Minnesota and western Wisconsin
will have the best chance of totals up to 1", with amounts tapering
to the west of I-35. HREF guidance portrays a scattered, convective
nature to the snow showers, which could result in isolated instances
of slightly higher amounts (~1.5" or so), but confidence in this
potential is low. Slick travel will be the main concern through the
evening, as the combination of freezing drizzle and light snow may
become a challenge for travelers on untreated roads. Brief
reductions in visibility are also possible as the snow falls.
A few snowflakes may continue into early Sunday, but the forecast
will improve well before any New Year`s Eve celebration plans
commence. With that said, high temperatures will remain below
freezing for much of the region Sunday, so it is plausible that a
few slick spots may linger through the day.
Quiet weather will be the theme for a prolonged stretch of time to
open 2024. Mother Nature`s New Year`s resolution will not be the
arrival of colder air, at least not through the first week of
January. Temperatures will top out above normal, in the 30s, for
much of the upcoming work week. Overnight lows will also remain mild
(by January standards!) in the mid 20s. Upper-ridging will keep any
mention of precipitation chances out of the forecast through at
least mid-week. Guidance swings a few shortwaves through the region
later in the week, but confidence in any precipitation is low at
this time. Looking into the long term, extended global ensemble
guidance is trending more active and potentially colder into the
second week of January.
&&
.AVIATION /00Z TAFS THROUGH 00Z MONDAY/...
Issued at 538 PM CST Sat Dec 30 2023
The stratus cloud deck continues to straddle the MVFR/IFR line
through tonight. Areas of freezing drizzle should begin to
transition to entirely snow in the next hour or so for terminals
in eastern MN and western WI. Reduced visibilities down to 2SM
are possible at times, but should remain primarily MVFR given
that snowfall rates like to be light. Accumulations around an
inch are still expected for terminals. Winds will continue out
of the northwest, gusting up to 25 kts at times overnight.
Things look to improve by mid-morning for most, with snow ending
and cigs gradually rising throughout the day.
KMSP... MVFR stratus prevails as the snow system moves through
tonight. Light snow will continue to fall with reduced
visibilities, up to 2SM during the peak of the system. Half inch
to an inch of snowfall is still expected. The main impacts from
snow should end around 10-12z, but cigs will remain MVFR until
nighttime before beginning to scatter out.
/OUTLOOK FOR KMSP/
MON...VFR. Wind WSW 5-10 kts.
TUE...Chc MVFR cigs. Wind NW at 5-10 kts.
WED...Chc MVFR cigs. Wind NWN at 5-10 kts.
&&
.CLIMATE...
Issued at 250 AM CST Fri Dec 29 2023
A record warm December is increasingly likely. Below is a table
of the current average temperatures for the month (through
12/29) and the record warmest average temperature for the
month.
Current Record
Twin Cities 34.8 33.8 (1877)
St Cloud 32.5 28.6 (1913)
Eau Claire 33.6 31.1 (1931)
Unless temperatures are far colder than our current forecast,
all three sites will likely set their warmest December on
record.
&&
.MPX WATCHES/WARNINGS/ADVISORIES...
MN...Winter Weather Advisory until midnight CST tonight for MNZ045-
052-053-060>063-068>070-076>078-084-085-093.
WI...Winter Weather Advisory until midnight CST tonight for
WIZ014>016-023>028.
&&
$$
UPDATE...BED
DISCUSSION...Strus
AVIATION...BED
CLIMATE...NDC
Area Forecast Discussion
National Weather Service Topeka KS
547 PM CST Sat Dec 30 2023
.KEY MESSAGES...
- Near normal temperatures through the coming week
- Small (10-20%) precipitation chances around Friday
&&
.DISCUSSION...
Issued at 223 PM CST Sat Dec 30 2023
Mid- and high-level clouds becoming less prevalent in recent hours
as a weak upper wave exits to the southeast. A stronger wave moving
east to southeast over the western Great Lakes ushers a cold front
through the local area tonight. Stratus is fairly widespread behind
this front early this afternoon but there is considerable guidance
spread in how this cloud deck will behave as it approaches Kansas.
Expect at least some sunshine by late afternoon Sunday, but despite
the cloud discrepancies, high temperature spreads are rather small
but still 10-15 degrees cooler than today.
Temperatures modify a bit Monday into Tuesday with warming Tuesday
muted by another round of high cloud, this time from the southwest,
downstream of a southern branch upper wave. Another modified cold
front swings through late Tuesday and Tuesday night for cooler temps
again Wednesday into Thursday. The aforementioned wave treks south
of the area, keeping a dry forecast going.
Precipitation chances return by late Friday with decent model
agreement on the next southern branch wave taking a somewhat farther
north track across the central and southern Plains. Temperatures
should be cool enough to support wintry precip types as well as
rain.
&&
.AVIATION /00Z TAFS THROUGH 00Z MONDAY/...
Issued at 545 PM CST Sat Dec 30 2023
VFR conditions continue early, with the main challenge this
forecast period being the progression of stratus currently
stretching across IA into northeastern NE. While variations
still exist between models, there is enough to lean towards a
more pessimistic solution with MVFR stratus moving into
terminals overnight. The HRRR in particular appears to be
handling it best currently, so have leaned on this with the
going forecast. Models that do bring the stratus into the area
are rather persistent with it through the day Sunday, so will
also need to monitor longevity if it does indeed move in, but
for now have it scattering out in the afternoon as a middle
ground solution. Otherwise, expect winds to turn slightly to the
north behind a cold front.
&&
.TOP WATCHES/WARNINGS/ADVISORIES...
None.
&&
$$
DISCUSSION...Poage
AVIATION...Picha
Area Forecast Discussion
National Weather Service Tulsa OK
924 PM CST Sat Dec 30 2023
...New SHORT TERM...
.SHORT TERM...
(The rest of tonight)
Issued at 924 PM CST Sat Dec 30 2023
Mostly clear skies were common across Eastern Oklahoma and
Northwest Arkansas at mid evening. However...to the north and west
a couple of low pressure systems were approaching the region. This
will allow for high clouds to spread into the CWA from the west
overnight as an upper low moves into the Four Corners region. At
the same time...a low pressure system currently over the Upper
Midwest is expected to slide southeast toward the Great Lakes
region with the eastern periphery of the base of the trof
approaching the CWA early Sunday morning. This will aid in low
clouds nearing the northern portion of the CWA toward daybreak
Sunday.
Also associated with the low pressure system to the north is a
cold front currently positioned from Northern Kansas into
Wisconsin. A leading wind shift out of the west to northwest ahead
of the cold front was dropping southeast into Southeast Kansas and
Central Missouri. This wind shift is progged to reach Northeast
Oklahoma over the next few hours and into Southeast Oklahoma and
West Central Arkansas around 12z Sunday. The trailing cold front
is then progged to reach into Northeast Oklahoma late tonight and
into far Northwest Arkansas Sunday morning. Behind the frontal
passage...breezy northerly winds transporting a cooler airmass
will spread southeast into the CWA for early Sunday morning. A
lack of available moisture is expected to keep the frontal passage
dry tonight/Sunday.
Temperatures overnight have begun and will continue to cool ahead
of the increasing cloud cover and cold front. Forecast lows in
the upper 20s to mid 30s remain on track for much of the CWA
tonight...with mid 20s possible near the Kansas border behind the
cold front. Thus...for the evening update...have added minor
adjustments to hourly temp/dewpoint trends into the overnight
hours to account for the rate of cooling underneath the currently
clear skies. Also added a few tweaks to sky cover based on the
mentioned above. The rest of the forecast seems to be handling
well at this time.
&&
.LONG TERM...
(Sunday through Saturday)
Issued at 109 PM CST Sat Dec 30 2023
Sunday will prove to be a bit colder across northeast Oklahoma
and northwest Arkansas with temperatures just a few degrees colder
than today south of I-40 as the cold front exits the area to the
south.
Monday is expected to be a little on the chilly side as high pressure
builds in behind the departing cold front. Temperatures on Tuesday will
a closer to normal as the surface high shifts to the east of the area
allowing for a return of southerly winds across the area. The next chance
of precipitation continues to be Tuesday night as a mid-level shortwave
moves out of the Southwest and across Texas. The models have trended further
south with this feature, keeping the bulk of the precipitation south of the
Red River. Will keep the precipitation in the form of rain across southeast
Oklahoma and west-central Arkansas late Tuesday night for now. However, the
forecast will be refined as the event draws closer.
The next chance of precipitation arrives late in the week and into Saturday as
a more vigorous mid-level low is forecast to move out of the Rockies and into the
Plains.
&&
.AVIATION...
(00Z TAFS)
Issued at 551 PM CST Sat Dec 30 2023
Cold front will push into northeast Oklahoma late tonight, moving into
southeast Oklahoma/northwest Arkansas Sunday morning with northerly
winds developing. Main forecast concern will be the potential for
low clouds to spread south into NE OK/NW AR TAF sites behind front
during the day. Given some of the latest HRRR and NAM RH fields/point
soundings, went ahead and added IFR/MVFR ceilings at KBVO/KXNA/KROG.
Southern edge of lower cloud deck may briefly stall near KTUL/KFYV
Sunday afternoon and this will be re-evaluated with 00Z model data.
&&
.PRELIMINARY POINT TEMPS/POPS...
TUL 30 43 23 43 / 0 0 0 0
FSM 32 53 29 47 / 0 0 0 0
MLC 31 50 26 46 / 0 0 0 0
BVO 25 43 20 42 / 0 0 0 0
FYV 27 47 22 44 / 0 0 0 0
BYV 31 43 24 42 / 0 0 0 0
MKO 30 45 24 44 / 0 0 0 0
MIO 27 41 22 41 / 0 0 0 0
F10 31 45 25 44 / 0 0 0 0
HHW 32 56 31 49 / 0 0 0 0
&&
.TSA WATCHES/WARNINGS/ADVISORIES...
OK...None.
AR...None.
&&
$$
SHORT TERM...20
LONG TERM....10
AVIATION...12