Forecast Discussions mentioning any of
"HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 12/01/24
AREA FORECAST DISCUSSION
National Weather Service Albany NY
933 PM EST Sat Nov 30 2024
.SYNOPSIS...
Lake effect snows continue in the western Adirondacks
through the weekend with several inches to multiple feet of snow
expected beneath the most persistent bands north of Route 28 and
west of Route 30. Elsewhere, cold and brisk but largely dry
conditions are expected through the weekend.
&&
.NEAR TERM /UNTIL 6 AM SUNDAY MORNING/...
Key Message:
- Lake-effect snow continues to impact the western Adirondacks.
Additional accumulations will be north and west of Routes 28
and 30 tonight.
.UPDATE...As of 930 PM EST...Few changes were needed with this
update as the forecast generally remains on track. Clouds have
decreased from the Capital District south and east courtesy of
southwest to westerly winds contributing to downsloping
throughout the Hudson Valley and mid-level moisture remaining
more confined to areas north. Made minor adjustments to
temperatures and sky cover to reflect latest obs, but all else
remains unchanged. Additional details can be found in the
previous discussion below.
.PREVIOUS DISCUSSION...
As of 359 PM EST...Cyclonic flow continues over the Northeast
as a mid and upper level trough is entrenched over eastern
Canada, the Great Lakes Region, Midwest and the Northeast. Lake
effect snow band continues to impact the western Adirondacks.
The Snow Depth change over the past 24 hours at the Old Forge
NYS Mesonet site is 13.0". The band is drifting northward into
tonight as the low-level flow backs slightly. The lake temp is
about 47F in Lake Ontario. Lake to H850/700 Delta T temps remain
18C/28C with moderate to extreme class instability based on
upstream model soundings east of Lake Ontario at KRME. The
inversion remains very high at 10 kft AGL. The low-level flow
backing to southwest/west will allow for the heaviest snow to
fall north of Stillwater Reservoir in the Wilderness tonight. An
additional 3-6" of snow may occur. South of the band snow
amounts will be very light.
Additional light snow showers and flurries may drift in from
lake Ontario moisture. We placed these snow showers and flurries
mainly west of the Capital Region. Any accums will be light.
Lows tonight will be chilly in the teens to lower 20s. Some
single digits are possible in the Catskills. It will be partly
to mostly cloudy in the moist cyclonic flow with cold advection
ongoing.
A Winter Storm Warning remains in effect in northern Herkimer
County for heavy lake-effect accumulations. A Winter Weather
Advisory remains in effect through 7 AM Monday in Hamilton
County for lesser additional accumulations.
&&
.SHORT TERM /6 AM SUNDAY MORNING THROUGH MONDAY NIGHT/...
Key Message:
- Lake-effect snows shift southward out of the west Adirondacks
into Monday.
Discussion:
The holiday weekend and December opens on a chilly note with
temps close to 10 degrees below normal. The 3-km HRRR and NAM
have the lake effect band start to drift southward off Lake
Ontario in the late morning. The flow becomes more westerly an
additional snowfall accumulations occur along and north of Old
Forge and Route 28. The band should persist into the afternoon
and then start to move southward at night. We kept the head
lines going until Monday morning. Most of the region will be
partly to mostly cloudy with cold and brisk conditions. Highs
will be in the 30-35F range in the valleys, southern Taconics
and northwest CT. Expect brisk west to northwest winds 5-15
mph.
The band is transitory and weakens in extension Sunday night, as
a short-wave moves through to disrupt the band. Additional snow
accumulations will range from 2 to 6 inches across northwest
Hamilton County with totals over multiple days 4-10". Northern
Herkimer County north of Old Forge will vary from 6" to 2 feet
for the event. Lows temps Sunday night will be in the teens.
Mon-Mon night...Will feature a lowering inversion and the low-
level flow being more northwesterly. Some multi-bands will form
over w-central NY and may shift into the western Mohawk Valley,
Schoharie Valley and the northern and eastern Catskills. Some
light snow accums of a a few tenths of an inch to a half an inch
will be possible. Otherwise it will be variable cloudy and cold
with highs close to the NBM values in the 20s to lower 30s over
the higher terrain and mid and upper 30s in the valleys. Cold
and mainly dry conditions Mon night with diminishing lake effect
southwest of the Capital Region with lows mainly in the teens to
lower 20s.
&&
.LONG TERM /TUESDAY THROUGH SATURDAY/...
Key Message:
- High confidence for below normal temperatures to continue with
additional chances for accumulating snowfall.
The mean mid and upper level trough will remain over southeast
Canada, the Great Lakes Region and Northeast to open the long term.
Low and mid level temp anomalies based on the latest NAEFS will be
-1 to -2 STDEVs below normal. Northwest flow persists with lake
effect snow showers and flurries persisting mainly west of the I-87
corridor. Depending on the trajectory, some light snow accums may
occur over the western Mohawk Valley, Schoharie Valley and northern
Catskills. It will remain chilly with temps close to 10 degrees
below normal with mid 20s to mid 30s for highs and some upper 30s in
the mid Hudson Valley. The mid level trough weakens Tue night into
Wed and the flow become zonal to southwesterly briefly. The lake
effect lifts northward and weakens potentially depositing some light
snow accums for the western Dacks. Ridging may briefly build in
from the south Tue night into early Wed with lows falling into the
teens. Clouds thicken and lower from west to east Wed pm for light
snow to occur ahead of a clipper low and its warm front. The
highest PoPs Tue pm continue to be from the Schoharie Valley and
Saratoga Region westward in the 40-70% range for light snow amounts.
Max temps will be similar to Tue.
Wed night into Thu looks to be the most impactful time for a
widespread light snow effect, but perhaps some moderate amounts for
the western Adirondacks and the western Mohawk Valley where some
south-southwest orographic flow enhancement may occur off the
southern Dacks. The isentropic lift increases, as the clipper
reaches southern Quebec. The closed H500 low remains near the
Quebec/southeast Ontario border. Cyclonic flow persists and PoPs
were raised to 60 to 90% across the forecast area based on the
latest NBM and guidance. The pcpn may diminish across parts of the
area south and east of the Capital Region in the late morning. A
strong cold front may move through during the afternoon with some
heavier snow showers or isolated squalls. Lows will be in the upper
teens to mid 20s over the forecast area. Highs Thu are projected in
the mid 20s to mid 30s over the hills and mtns...and mid 30s to
around 40F in the valley areas.
Thu night strong cold advection occurs over the forecast area. 850
hPa temp anomalies will be -1 to -2 STDEVs colder than normal. The
actual values may fall to -12C to -16C. Lake differential temps
look favorable for more lake effect snow Thu night into Fri. A
shift to multi-bands in northwest flow may occur by Friday. It will
be blustery and cold to close the week with max temps struggling to
get out of the teens and 20s. Wind Chills in the single digits to 10
degrees or so below zero will be possible over the Adirondack Park.
The winds may subside by Saturday, but temps will run 10-15 degrees
or so below normal for early Dec. A few snow showers or flurries
may linger over the western Adirondacks. The CPC Day 8 to 14 Temp
and Pcpn Outlook for eastern NY and western New England is
forecasting below normal temps and near normal pcpn for the 2nd week
of December.
&&
.AVIATION /03Z SUNDAY THROUGH THURSDAY/...
Through 00Z Monday...VFR conditions prevail at all terminals
this evening with variable cloud cover across eastern New York
and western New England. VFR conditions will prevail throughout
much of the 00z TAF cycle, with ceilings generally ranging
between 5-15 kft. However, some guidance hints that KGFL and
KPSF could develop MVFR ceilings for a brief time overnight
between 06-10z. Mentioned brief TEMPOs in these TAF groups to
account for the possibility. Otherwise, winds will prevail out
of the southwest to start before gradually backing more towards
the west by the end of the period. Sustained speeds will
generally fall below 10 kt.
Outlook...
Sunday Night Monday Night: No Operational Impact. NO SIG WX.
Tuesday: Low Operational Impact. Slight Chance of SHSN.
Tuesday Night: No Operational Impact. NO SIG WX.
Wednesday: Moderate Operational Impact. Chance of SN.
Wednesday Night: High Operational Impact. Likely SN.
Thursday: Moderate Operational Impact. Breezy. Chance of SHSN.
&&
.ALY WATCHES/WARNINGS/ADVISORIES...
CT...None.
NY...Winter Storm Warning until 7 AM EST Monday for NYZ032.
Winter Weather Advisory until 7 AM EST Monday for NYZ033.
MA...None.
VT...None.
&&
$$
SYNOPSIS...Wasula
NEAR TERM...Gant/Wasula
SHORT TERM...Wasula
LONG TERM...Wasula
AVIATION...Gant
Area Forecast Discussion
National Weather Service Binghamton NY
656 PM EST Sat Nov 30 2024
.SYNOPSIS...
Cold weather expected through the weekend into early next week
under as a upper level trough remains in place. Lake effect snow
will remain north of our region with mainly flurries at times
this afternoon through Sunday but the band shifts south Sunday
afternoon, impacting the NY Thruway corridor.
&&
.NEAR TERM /THROUGH MONDAY/...
650 PM Update:
Partly cloudy skies out there this evening with a few, isolated
light snow flurries on-going across Cortland, Cayuga, Onondaga
and Oneida counties. Temperatures have already fallen back into
the 20s and low 30s areawide. It will be quite cold tonight with
lows in the 10s to low 20s over the region. Another cold and
partly cloudy day (with a few isolated flurries) on tap for
Sunday; highs in the mid-20s to lower 30s expected. The lake
effect doesn`t shift south into Central NY until the Sunday
evening hours. Touched up PoPs, and increased details in the
PoPs/wx grids for when the lake effect snow band is expected to
shift south Sunday evening/night.
Was contemplating whether the current winter weather advisories
for S.Cayuaga and Onondaga should be extended in time through
at least Monday evening, as the 18z CMC regional model keeps
steady lake effect snow going through the day...however the HRRR
and 3km NAM dissipate or break up the lake effect snow bands at
differing times on Monday; so confidence remained low enough to
not extend advisories yet. Will wait and take a look at newer
guidance before making any decisions on this aspect of the
advisory...as uncertainty does remains a bit higher than usual
on when the lake effect will break up. So for now, the winter
weather advisory remains in place 10 PM Sunday through 10 AM
Monday morning for the two forecast zones noted above.
200 PM Update...
With the stratocumulus layer sitting right at the dendritic
growth zone, there has been widespread light flurries across the
region this morning into the afternoon. Forecast soundings show
that the DGZ will remain saturated into the evening so flurries
have been added into the grids through the afternoon. Some
flurries have been added in for tomorrow as well as many
forecast soundings show a return of the stratus layer at the DGZ
so there will be potential once again mainly north of the
Southern Tier. With a long wave trough set up overhead and
persistent NW flow under it, we will remain cold through the end
of the weekend with temperatures struggling to get above
freezing.
Lake effect snow is expected to stay north of the region and
mainly impact the northern Tug Hill through at least mid day
tomorrow before a shortwave moving in begins to turn the flow
more northwesterly. Forecast soundings late Sunday afternoon and
overnight are favorable for organized snow bands into Onondaga
and Cayuga counties. As of now, the forecasted environment is
not too favorable for deep inland extent of the snow bands so
the heaviest snow accumulations will be limited to the northern
western portion of Onondaga and central Cayuga counties.
&&
.SHORT TERM /MONDAY NIGHT THROUGH TUESDAY NIGHT/...
West to northwest winds look to continue into Monday. The flow
coming off of a warmer Lake Ontario should result in additional lake
effect snow showers. The most concentrated area of snow showers
given the wind direction should be focused into eastern Cayuga and
western Onondaga counties where a winter weather advisory has been
issued for. Even though the QPF looks light given a lack of forcing
higher snowfall ratios should be able to offset that some. Snowfall
totals of around 4 inches in spots look likely at this time with
lower totals further southeast. Some snow showers may advance
eastward into Steuben county as well from Lake Erie. These also look
to be fairly light Monday. While several degrees warmer, highs still
look to only get to around freezing.A break in the action should
occur Tuesday night with winds shifting to southwesterly ahead
of an approaching clipper system.
&&
.LONG TERM /WEDNESDAY THROUGH SATURDAY/...
Modeling and ensemble guidance still some differences in the
overall track of the clipper. The track looks to be north of
the region across New England Wednesday and Thursday. Still,
enough lift looks present for an area of light snow to develop
Wednesday afternoon and night ahead of a warm front. Might have
to watch the Froude number with this event to see if there are
any areas of enhancement or missed locations in terms of QPF.
Ground temperatures should finally be cold enough for
accumulations in valley locations as well. Another inch or two
of fluff could occur with possibilities expanding into more of
the region. If the track shifts slightly to the north less QPF
would be observed in NE PA and the southern Tier of NY.
Given the southerly flow, temperatures may warm a few degrees above
freezing as well in NE PA Wednesday. So brief mixes with rain can
not be ruled out in the Wyoming Valley. Temperatures still generally
20`s and 30`s given the cloud cover and general flow pattern.
While to early to get a pinpoint on exact details this far out this
looks like a favorable setup for snow squalls ahead of the main cold
front early Thursday. This should transition to another Lake
Effect event with west-northwest flow into Friday. Yet another
clipper may follow with additional snow showers and Lake Effect
snow showers on Saturday.
A fairly potent cold airmass looks to move in Thursday through
Saturday. This looks to knock temperatures back into the teens and
20`s. Model soundings show an increase in winds as well, so wind
chills near 0 at times is not out of the question.
&&
.AVIATION /00Z SUNDAY THROUGH THURSDAY/...
ITH and BGM should see ceilings dipping in and out of MVFR
conditions over the next couple hours as some lake clouds
continue to move across the region. VFR conditions expected for
all terminals through tonight and tomorrow. Ceilings at ITH and
BGM could fall into MVFR again tomorrow afternoon, but
confidence is not high enough at this time to include it in the
TAFs. Winds will remain blustery, gusting to 18-25 kts across
the region out of the WSW.
Outlook...
Sunday Night...Lake Ontario snow band will push south and should
bring restrictions to SYR and/or RME.
Monday and Tuesday...A shift to NW winds and a multi-lake
connection will increase the probability of lake effect snow
and associated restrictions at CNY terminals, possibly even
extending as far as AVP at times.
Wednesday into Thursday...A low pressure system moving through
Southern Canada may bring scattered snow showers with associated
restrictions.
&&
.BGM WATCHES/WARNINGS/ADVISORIES...
PA...None.
NY...Winter Weather Advisory from 10 PM Sunday to 10 AM EST Monday
for NYZ017-018.
&&
$$
SYNOPSIS...AJG
NEAR TERM...AJG/MJM
SHORT TERM...MWG
LONG TERM...MWG
AVIATION...JTC
Area Forecast Discussion
National Weather Service Des Moines IA
544 PM CST Sat Nov 30 2024
...Updated for the 00z Aviation Discussion...
.KEY MESSAGES...
- Flurries may fly over western into parts of central Iowa through
this evening.
- A 20 to 30% increase in light snow and flurry chances from previous
forecast for Sunday afternoon into Sunday night over
northwest into central Iowa. Chances are now 30 to 50% in
these areas. Accumulations under an inch currently forecast.
- Below normal temperatures much of the period.
&&
.DISCUSSION...
Issued at 150 PM CST Sat Nov 30 2024
The overall synoptic pattern features a broad trough over
eastern North America with a ridge over the West Coast of the
same continent. While this pattern will shift a little through
the week, Iowa will remain beneath largely northwesterly flow
keeping shortwave troughs passing overhead or nearby with
generally limited moisture for any significant QPF. Temperatures
will be below normal with the only day that may be around our
early December normals on Wednesday.
At present, the winter friendly Day Snow Fog RGB shows a large area
of stratus moving in from northeastern Nebraska and South Dakota
with surface observations reporting light snow or flurries beneath
these clouds in some areas. Forecast soundings show that much of the
saturation within these stratus clouds is near or resides within the
dendritic growth zone (DGZ). These snowflakes are overcoming very
dry subcloud layer air in the lowest 2000 to 3000 feet with recent
mPING reports over western Iowa north of SUX and near CBF showing
dewpoint depressions of 15F. Have maintained and slightly expanded
the flurry mention about a county north and east from previous
forecast through mid-evening. These clouds will depart, but latest
HREF continues to advertise a 20% chance or less that low stratus
will arrive from the north toward sunrise Sunday morning. These
clouds could make it as far south as a Grinnell to Ames to Fort
Dodge line. Further, these clouds may have enough moisture for
flurries given their moisture resides in the DGZ, but given the
chance of occurrence have not advertised that in the official
forecast.
The biggest change to the forecast is Sunday afternoon and evening
with the forecast now advertising light snow and flurries over much
of central Iowa. As the previous discussion noted and this morning`s
deterministic models showed, there remains a low QPF event in this
time frame. This light snow event is due to a stronger shortwave
trough that dives southeastward with favorable large scale ascent
from upper level jet streaks and low level QG convergence. While it
is model dependent, HRRR runs show a very deep layer (8000 feet) of
saturation within the DGZ with the NAM and GFS not quite as deep
(5000-6000 feet). This depth of saturation coupled with weak omega
should result in snow production. The initial National Blend of
Models had less than 15% chance PoPs, but given the thermodynamic
and kinematic fields at play, feel confident in the increase in
PoPs. While QPF will only be a few hundredths and resulting snowfall
is forecast to be under an inch, any untreated roadways may result
in slick roads, particularly as holiday travel winds down and work
week traffic picks up Monday morning.
Temperatures will remain below normal through the upcoming week
except for Wednesday. As high pressure slides into the Tennessee
River Valley, our surface flow becomes more southwesterly and our
upper level northwesterly flow becomes a bit more westerly. This
will allow for temperatures to peak in the upper 30s to low to
middle 40s on Wednesday - the warmest of the week! However, more
cold air arrives late this week behind a cold front. Large scale
precipitation chances are muted below 20% through the end of the
week in the cluster analysis and our official forecast shows a dry
forecast as well.
&&
.AVIATION /00Z TAFS THROUGH 00Z MONDAY/...
Issued at 544 PM CST Sat Nov 30 2024
Mid level clouds largely remain across portions of
west/southwest Iowa this evening, with any ongoing flurries or
light snow remaining west of KFOD and KDSM. This activity is
expected to diminish over the next few hours, with clouds moving
out for a brief period that will improve ceilings, before
another wave of cloud cover returns mainly after 18z Sunday from
northwest to southeast. Additional flurries/light snow become
possible near the end of the period Sunday and look to remain
through the evening. More details will be included in the next
issuance. Otherwise winds remain light out of the northwest.
&&
.DMX WATCHES/WARNINGS/ADVISORIES...
None.
&&
$$
DISCUSSION...Bury
AVIATION...Ansorge
Area Forecast Discussion...UPDATED
National Weather Service Hanford CA
651 PM PST Sat Nov 30 2024
.UPDATE...
Updated AIR QUALITY ISSUES section.
&&
.KEY MESSAGES...
1. Dry weather will prevail through next week with above
average temperatures.
2. Late night and morning fog will be possible every day
through next week in the San Joaquin Valley.
&&
.DISCUSSION...
The ridge over Interior Central California slowly shifts east
tomorrow as an upper level weakness develops over the Golden
State then hangs around through Wednesday and then shifts south
over Baja California Thursday into next weekend as another
ridge builds into the region.
The focus tonight and for the next several nights and mornings
will be fog concerns. The cloud cover has broken up over already
along the Highway 198 corridor and west side hills this
afternoon. The probabilistic guidance has low probability of the
fog and stratus hanging around the rest of the valley this
afternoon. The cloud cover is a factor in the the fog for the
overnight hours. LAMP probabilistic guidance along with NBM
aviation guidance have likely probabilities of low visibilities
and dense fog conditions mainly north of Fresno and south of
Hanford. The trend of clearing looking at the visible satellite
does support the Hanford south solution. Looking at high res
ensembles probabilities for the morning hours shows increased or
greater than 60 percent probability of dense fog along the
Highway 99 corridor. The HRRR highlights the northern areas and
the area south of Hanford. The solution for now is to wait to
see the extent of the clearing. Then issue the new DFA this
evening.
This plays out for the next couple of mornings. The upper level
disturbance brings a ever so slim chance for High Sierra snow
showers late Sunday and Monday. When looking at deterministic
model solutions there is mid to upper level upward motion in the
atmosphere however in the lowest 100 MB there is suppression
that could lead to more fog events through the week.
The average high is around 60 to 62 this week. Taking 61 as a
proxy for the average in the San Joaquin Valley the
probabilities of exceeding 61 range from 85 to near 100% at all
locations. Going up to 65 degrees the probability of exceedance
ranges from 35 to 65 percent. The alternate solution would be
stratus cloud cover that could keep temperatures down. This is
dependent on how much mixing is in the lowest levels along with
residual moisture.
Looking out through the CPC 8 to 14 day keeps the above normal
temperatures and below normal precipitation going.
&&
.AVIATION...
00Z TAF issuance:
IFR ST deck with IFR-MVFR VSBY continues at all terminals with
the exception of KVIS where the CIG has lifted. The
probabilistic guidance for 06Z-18Z with the NBM has a likely
probability of LIFR/IFR at all terminals. LAMP probabilities
show likely LIFR/IFR from 08Z thru 17Z at the terminals. Plan on
going IFR for now and allow the 06Z issuance handle the LIFR
probs for the early morning hours. The current cloud cover
provides just enough of a chance not to bring LIFR across the
board for the 06-10Z departures.
Elsewhere, VFR with scattered high cloudiness and light wind for
the Sierra and Kern County desert.
&&
.AIR QUALITY ISSUES...
On Sunday December 1 2024, Fireplace/Wood Stove Burning Status
is: No Burning Unless Registered in Fresno, Kern, Kings, Madera,
Merced, and Tulare Counties. Burning Discouraged in Kern (Greater
Frazier Park Area) and Sequoia National Park and Forest.
&&
.CERTAINTY...
The level of certainty for days 1 and 2 is medium.
The level of certainty for days 3 through 7 is medium.
Certainty levels include low...medium...and high. Please visit
www.weather.gov/hnx/certainty.html for additional information
and/or to provide feedback.
&&
.HNX WATCHES/WARNINGS/ADVISORIES...
None.
&&
$$
Operations...Proton
IDSS.........SM
weather.gov/hanford
Area Forecast Discussion
National Weather Service Marquette MI
530 PM EST Sat Nov 30 2024
.KEY MESSAGES...
- Long duration moderate to occasional heavy lake effect snow event
should be gradually winding down Sunday into Monday, although
locally moderate snow accumulation is still expected into east and
north central portions of the U.P. Winter storm warnings and
advisories remain in effect tonight into Sunday.
- Another Clipper system moving through the area late Tuesday into
Wednesday will bring widespread system snow late Tuesday into
Tuesday night with another uptick in lake effect snow behind it
Wednesday into Thursday for the nw-n Lake Superior snow belts.
- Temperatures remain below normal through early next week, then
will trend well below normal for late next week.
&&
.SHORT TERM /THROUGH TONIGHT/...
Issued at 258 PM EST Sat Nov 30 2024
Water vapor imagery and RAP analyses have midlevel troughing in
place over the Great Lakes, with a surface low south of James Bay.
Another embedded shortwave is seen moving through western Ontario
this afternoon, with chilly WNW flow out ahead of it keeping in lake
effect snow showers mainly in the westerly or WNW wind snow belts in
the western and eastern UP. Thus, much of the UP is currently seeing
a brief let-up in snowfall. The heaviest snowfall rates are
currently seen across the Keweenaw and in Alger and Luce counties,
generally around and east of Munising. HREF continues to point to
snowfall rates around a half inch/hr in those eastern zones, perhaps
higher at times, and webcams continue to show sporadic heavier bursts
of snowfall. So, would not be surprised by some areas picking up
another couple of inches through the afternoon and early evening.
Meanwhile, as winds remain gusty, particularly nearer to Lake
Superior, further reductions in visibility will be possible in snow
showers.
This evening, the aforementioned wave off to our north drops
through. Model soundings show inversion heights increasing once
again while winds veer more to the NW. This could spell a
reinvigoration in snowfall over the western UP while the bands in
the eastern UP drop more westward once again. A widespread 2-4in of
snow is expected across the NW wind snow belts in the western UP,
with some locally higher amounts around/in excess of 6in in the
higher terrain north of Ironwood northeast to around White Pine. To
the east, another widespread 3-7in is likely, with some of the
"lucky" (depending on your definition) spots picking up as much as 8-
10in by sunrise Sunday. Snow bands may extend farther inland in the
eastern UP with the long fetch off of Superior, even reaching as far
southward as Lake Michigan. So, lighter snow accumulations will be
possible across the US-2 corridor. However, with elevated winds
overnight closer to Lake Superior potentially leading to further
reductions in visibility, travel conditions would be most hazardous
across Hwy-28 in Alger and northern Schoolcraft counties, and
traveling from Munising to Grand Marais. Will opt to keep the
winter headlines in place despite the brief break in activity this
afternoon, in anticipation of this next wave. However, will likely
drop the advisory over southern Schoolcraft county as snowfall rates
and amounts look to be less impactful the rest of the weekend.
&&
.LONG TERM /SUNDAY THROUGH SATURDAY/...
Issued at 348 PM EST Sat Nov 30 2024
Surface-850 mb winds are expected to veer more northerly Sunday into
Monday in the wake of a weak shortwave/sfc trough passage late
tonight. This more northerly wind direction should allow Lake
Superior LES bands to push farther inland Sunday into Monday.
However, with surface ridging building in from north of the lake
generally light to moderate fluffy LES accumulation is expected
Sunday into Monday as 850 mb temps -11C to -12C yield lake-850 mb
delta-t values of 18-19C. The only exception will be the likelihood
of a locally heavy LES band setting up somewhere over western Alger,
where low-level convergence will be enhanced by land breezes and
fetch will be effectively lengthened by preconditioning off of Lake
Nipigon.
Late Mon night into Tuesday, winds back westerly in response to a
surface ridge moving across the area from the Plains. The backing
winds and associated subsidence from the ridge should further
taper LES off from west to east late Mon night into Tue.
Models show the next Clipper shortwave and associated low pres
system moving into the Upper Great Lakes late Tuesday into
Wednesday. Warm advection/isentropic ascent ahead of the system will
bring widespread light to possibly moderate system snow to the area
late Tuesday into Wednesday. Behind the Clipper system the coldest
air mass of the season thus far will be ushered into the region late
Wednesday into early Friday on the heels of N-NW winds as 850 mb
temps fall to -16C to perhaps as low as -20C. The cold airmass
combined with a cyclonic/convergent N-NW sfc-flow will support
moderate to heavy LES and considerable blowing and drifting of snow
with N-NW winds possibly gusting as high as 30-40 mph late Wednesday
into Thursday. Wind chills will also plummet to 0C or below late Wed
night into Thu night. Another round of winter storm warning
headlines seems like a pretty good bet as we get closer to the
event.
Models indicate ridging moving in on Friday which should taper off
LES from the west. Models then hint at another weak clipper moving
through which could bring light snow back into the area Fri night
into Saturday.
Below normal temps early in the week will trend well below normal
late week behind the stronger midweek Clipper system.
&&
.AVIATION /00Z TAFS THROUGH 00Z MONDAY/...
Issued at 529 PM EST Sat Nov 30 2024
Ongoing northwest wind lake effect snow event continues to result in
flight restrictions for all TAF sites. Most impacted will be IWD and
CMX, with MVFR predominant at IWD and IFR or worse restrictions at
CMX. Elsewhere, SAW will be MVFR with periods of IFR. As winds shift
more northerly into early Sunday, CMX may see an improvement to
MVFR. Gusts at CMX could reach 30 kts.
&&
.MARINE...
Issued at 348 PM EST Sat Nov 30 2024
High pressure to the west and a weakening low pressure over James
Bay through the rest of the weekend continues the gusty northwest
winds over Lake Superior. Expect northwest winds 20-30 kts
continuing through Sunday with gale force gusts to 35 knots over the
east half through tonight. With high pressure approaching the Great
Lakes for early next week, winds veer north Sunday night, falling
back to 15-25 kts. Winds gradually diminish through Monday, falling
below 20 kts across the lake by Monday evening. Winds back west for
Tuesday and southwest for Tuesday night as the high pressure moves
to the southwest. As a clipper low passes near Lake Superior,
northwest to north winds are re-invigorated behind the associated
cold front on Wednesday. Gales to 40 kts are becoming increasingly
likely late Wednesday into Thursday with the strongest winds
expected over the east half of the lake, where there is a 20-40%
chance of storm force gusts to 50 knots per EPS probability fields
during this time. Waves could reach 12 to 16 feet late Wed night
into Thursday, highest east half. In the wake of the low, northwest
winds gradually diminish to 20-30 kts Thursday night and 15-25 kts
for Friday.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
Upper Michigan...
Winter Weather Advisory until 7 AM EST /6 AM CST/ Sunday for
MIZ001>004-009-084.
Winter Storm Warning until 7 PM EST Sunday for MIZ006-007-085.
Lake Superior...
None.
Lake Michigan...
None.
&&
$$
SHORT TERM...LC
LONG TERM...Voss
AVIATION...07
MARINE...Voss