Forecast Discussions mentioning any of
"HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 01/16/23
Area Forecast Discussion
National Weather Service Binghamton NY
713 PM EST Sun Jan 15 2023
.SYNOPSIS...
High pressure moving in with clearing skies this afternoon and
tonight. An active pattern will continue this week with a weak
system coming in on Tuesday, bringing a wintry mix and rain and
another system expected Thursday into Friday.
&&
.NEAR TERM /THROUGH MONDAY NIGHT/...
645 PM Update
Low stratus clouds are holding tough across much of Central NY,
and have even expanded a bit further south right into the
Southern Tier since sunset. The overall flow is very light with
high pressure starting to move in from the west. Therefore,
these clouds are expected to remain nearly stationary (perhaps
drifting west) through much of the overnight period. Also added
in some patchy freezing fog overnight into early Monday morning,
as the consshort guidance was indicating some visibility
reduction, and dew point depressions are already low. The GOES-
east meso sector 1 minute Nighttime microphysics satellite loop
is already showing signs of fog or very low stratus clouds out
there, and is also indicating some interesting features downwind
of the Cortland/Onondaga County ski resorts once again...but we
are not seeing any snow being reported at this time. Overnight
lows will be tricky and impacted by how long and exactly where
this cloud cover remains in place. Right now, did not make
significant changes to the forecast overnight low...still going
for mainly 10s across the area, and perhaps some single digits
for northern Oneida county and/or the northern Catskills.
315 PM Update...
High pressure continues to build into the region with clearing
skies. However, with the northerly flow, cloudy conditions will
continue across the Finger Lakes Region and portions of Central
NY into tonight. Low temperatures tonight will again be
dependent on where the the clouds have cleared. Radiational
cooling will produce single digit readings across Northern
Oneida County and possibly some of the sheltered valleys in the
Catskills as well. Most of the area will see low in the teens
tonight but with the Finger Lakes continuing to have cloud
cover, temperatures will remain a few degrees warmer overnight.
High pressure continues on Monday with mostly sunny skies and
warmer temperatures expected. Highs will be in the mid 30s to
low 40s across the area. Our next system will start to push in
from the west early Tuesday morning, however at this time it
appears that precipitation will remain west of the region until
after the near term period.
&&
.SHORT TERM /TUESDAY THROUGH WEDNESDAY NIGHT/...
245 PM Update:
A weak low pressure system will move through the Great Lakes
Region on Tuesday. Dry air at the onset will likely keep most of
the precipitation from starting until the late morning/early
afternoon, and even that is expected to be light. A light wintry
mix of freezing rain and snow will be possible, before most
areas change to rain during the afternoon. Light ice
accumulations are possible, but the chances are that this will
be rather isolated. High temperatures are expected to be in the
mid 30s to mid 40s.
Tuesday night into Wednesday, a westerly flow will develop on
the backside of this system, allowing for some light lake
enhanced rain and snow showers. Temperatures will remain rather
mild with lows in the 30s and highs in the mid 30s to mid 40s.
By Wednesday night, any remaining lake effect rain and snow
showers end, with a brief dry period before the next system
moves in.
&&
.LONG TERM /THURSDAY THROUGH SUNDAY/...
245 PM Update:
Another system will move through the Great Lakes Region Thursday
into Friday, which will bring another brief wintry mix, changing
to rain, and then changing to lake effect snow showers as it
departs on Friday. Then by Saturday, high pressure moves into
the region, allowing for mainly dry weather. Another system may
bring a round of precipitation Sunday or Monday. With plenty of
uncertainty this far out, continued to stick with the National
Blend of Models for temperatures and PoPs for the weekend.
Temperatures in the long term looks to be seasonably mild with
highs in the 30s and 40s and lows in the 20s and 30s.
&&
.AVIATION /00Z MONDAY THROUGH FRIDAY/...
Challenging forecast overnight as low cloud cover expanded back
into ELM and BGM. This is much further than any guidance or
model indicated, but the same guidance (including 1km
experimental HRRR nest) show the more limited cloud cover more
or less staying put through dawn. So while ELM and BGM are on
the fringes of the low ceilings, it is likely here to stay.
SYR is more tricky, as the back edge of the low cloud cover is
just onshore south of Oneida Lake. Models show low level winds
veering slightly to the NE, which may push the clearing into SYR
in a few hours, as reflected in the TAFs.
Ceilings will be in the fuel alt range for most sites, gradually
dropping into IFR territory through the night (ITH and BGM are
already there). Some patchy (freezing) fog may develop at SYR
after they clear out and winds diminish. ITH and BGM could see
light freezing fog/mist if ceilings can settle a little lower.
AVP looks to stay VFR through the night.
All sites should return to VFR between 13Z and 15Z Monday,
holding through the day.
Outlook...
Monday Night...VFR.
Tuesday through Friday...Restrictions possible with wintry mix
early Tuesday, changing to rain showers and continuing into
Wednesday. Another system will bring more rain and restrictions
on Thursday and Friday.
&&
.BGM WATCHES/WARNINGS/ADVISORIES...
PA...None.
NY...None.
&&
$$
SYNOPSIS...MPK
NEAR TERM...MPK/MJM
SHORT TERM...BJG
LONG TERM...BJG
AVIATION...MPK/MPH
Area Forecast Discussion
National Weather Service Burlington VT
935 PM EST Sun Jan 15 2023
.SYNOPSIS...
A chilly night is anticipated across the North Country with some
intervals of clouds and mainly light winds. On Monday, clouds will
thicken across central and eastern Vermont with some light snow
possible toward the Northeast Kingdom. Only very minor accumulations
are expected. The next weak system impacts the region for mid week
with a light wintry mix of precipitation, before a stronger system
arrives late week with temperatures trending back above normal
again.
&&
.NEAR TERM /THROUGH MONDAY NIGHT/...
As of 932 PM EST Sunday...Main changes with this update was to
adjust temperatures down a bit across northern NY. Skies remain
clear across much of the area this evening, and locations have
dropped into the single digits across much of northern NY, with
a couple spots already below zero. Many locations in VT are also
trending a bit colder than previously anticipated, as high
clouds are eroding as they stream westward and encounter dry air
and ridging. Can see some thicker clouds starting to approach
the CT River Valley at this hour, and these should help limit
additional cooling as we head toward early Monday morning. Other
than the temperatures, the rest of the forecast remains on track
and no other changes were needed.
Previous discussion...Water vapor indicates a rather complex
mid/upper lvl pattern acrs the ne conus with strong s/w ridge axis
centered over the eastern Great Lakes, while deepening closed
cyclonic ocean storm is advecting mid lvl moisture back toward
eastern VT. Plenty of minor details to the fcst over the next 12 o
24 hours, but overall impacts look to be minimal attm. Mainly
cloud/temp fcst challenge tonight, followed by cloud/precip and temp
focus for Monday. Have noted trends in the 12z guidance was to push
slightly higher qpf back into eastern/NEK of VT on Monday, but still
not completely sold on this scenario, given our crnt pw values are
0.10", which is very dry even for mid Jan. This dry air, at least
aloft should help produce mostly clear skies tonight and allow temps
to drop quickly as sharp and shallow llvl thermal inversion
develops. Lows range from -5F colder parts of the western dacks/slv
to mid teens/lower 20s eastern VT and summits. Have continued with
previous fcst idea of showing sharp contrast btwn deeper/protected
valleys and higher summits. Developing cloud canopy wl keep eastern
VT warmer overnight. RAP sounding data suggestion low clouds acrs
the CPV and parts of the SLV should finally dissipate btwn 21z-03z
this evening. Have noted the potential for freezing fog at MSS again
as temps fall way below cross over values and mainly light ne winds,
so have placed in fcst btwn 08z-12z for SLV. Also, have noted
pressure gradient increases btwn sub-990mb low pres over western
Atlantic and 1030mb high pres overnight tonight into Monday, with
925mb to 850mb winds of 35 to 45 knots, supporting better mixing
acrs the summits.
The question for Monday wl moisture be able to overcome very dry
atmosphere and produce some light snow, possibly mixed with
sleet/freezing rain acrs our eastern VT zns, including the NEK.
Trends in the 12z guidance has been to take deep closed cyclonic
circulation and retrograde enhanced 850 to 500mb rh back into VT.
However, this wl be backing into strong ridging aloft with deep dry
layer in place, resulting in precip falling apart as it pushes
toward our eastern cwa. Have bumped pops into the chc range from
roughly 15z to 21z on Monday with some minor snow accumulation of a
dusting to 0.3 possible. Thermal profiles continue to be challenging
as some warmer air is rotating into the region on northeast flow,
but also a pocket of cooler 925mb temps remain over our central fa,
while 850mb temps approach 0C over the southern SLV by 21z Monday.
Have temps mainly in the mid 20s eastern VT to upper 20s/mid 30s
elsewhere.
Monday night complex mid/upper lvl pattern prevails as strong ridge
is squeezed from approaching Great Lakes system and slow moving
ocean storm to our east. Lobes of mid lvl moisture continue to
rotate back toward our eastern cwa, but still questions on potential
for precip. For now have mainly a dry fcst with seasonably cool
temps.
&&
.SHORT TERM /TUESDAY THROUGH WEDNESDAY/...
As of 349 PM EST Sunday...A nuisance-level precipitation event will
occur during this period. Expect widespread but short-lived light
mixed precipitation followed by rain/snow showers late Tuesday into
Wednesday. A weakening low pressure system and broad upper level
trough will drift across our region, and the upper level divergence
along with some weak frontogenesis will help moisten an initially
very dry atmosphere. The thermal profiles that will determine
precipitation type are rather challenging, with a lot of variability
as to how much warming occurs aloft out ahead of the low pressure
system. The latest GFS is rather cold compared to the equivalent
period from the NAM12, and expect it is too cold; as such, have
preferred to show some freezing rain chances. Most model guidance
suggests a relatively deep melting layer, with a small/shallow
refreeze layer; precipitation would tend to fall as freezing rain
given the low level inversion that will maintain fairly cold surface
temperatures, especially with regards to wet bulb temperatures.
Currently show light ice accumulations of less than a tenth of an
inch possible over much of the Adirondacks and southern St. Lawrence
Valley through Wednesday morning, and over some of the higher
terrain in Vermont, although eastward progress of the precipitation
makes amounts more questionable as one goes north and east. During
the daytime precipitation will become more of a scattered rain and
snow shower regime as the upper level trough passes overhead and we
see weak cold air advection. Low level temperatures will be warm
enough, rising into the 35 to 40 range, for mainly rain showers in
the deeper valleys, with mainly wet snow showers elsewhere. As flow
becomes more northwesterly during the afternoon, a minor upslope
snow event will occur in with accumulations mainly 2" or less.
&&
.LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/...
As of 349 PM EST Sunday...Quiet weather to start the period through
midday Thursday, then precipitation chances quickly ramp up from
southwest to northeast Thursday afternoon with another low pressure
system moving into our region from the southwest. A range of
possible outcomes still on the table with the latest data despite
fairly good clustering of storm tracks. While there is a high
probability (>75%) of widespread snow areawide by Thursday night,
with the initial low tracking to our west and lack of a strong area
of high pressure to our north, many ensemble members show a
changeover to mixed precipitation or rain somewhere in northern New
York and Vermont. As such, have indicated snow with a chance of rain
for most locations, especially south, where probability of rain is
greater. The sooner a secondary low pressure area develops and
strengthens in the vicinity of coastal southern New England, the
more likely an all snow event is in the cards for all locations. A
lack of upstream blocking will make this a fairly short duration
event with steady precipitation departing Friday morning. The main
factor in determining if snowfall amounts will be on the light side
(roughly 2-4") versus a moderate event (roughly 5-10") is the
amplification of the upper level trough. Model solutions with a more
amplified trough produces stronger thermal gradients and
precipitation rates are briefly heavy, while a flatter pattern keeps
low pressure from deepening with weak frontogenetic forcing leading
to lighter precipitation. There is a bit higher probability of the
former scenario, but not overwhelmingly so - however, at least some
widespread snow accumulation looks highly likely even with some
mixed precipitation chances. General troughiness across the
Northeast US remains behind this storm, so snow shower chances
linger through the weekend. High temperatures look near seasonable
through much of the period, although average temperatures should be
above normal given prevalence of cloud cover.
&&
.AVIATION /03Z MONDAY THROUGH FRIDAY/...
Through 00Z Tuesday...VFR to prevail at all terminals through at
least 12z Monday; KMSS is the exception where expect freezing
fog to develop again late tonight/early Monday; visibility
reduced to 2SM and ceilings to 200 ft at times 09z-12z.
Otherwise, high clouds slowly increase from the east, lowering
to MVFR at KEFK and KMPV after 15z Monday. Surface winds will
remain out of the north at 5-15 kt, but expect winds to
increase to 35-45 kt between 2000 and 4000 feet overnight, while
low levels decouple resulting in areas of wind shear and
turbulence, especially central/eastern sites. Precipitation may
make it as far west as KEFK, but have kept mention restricted
to VCSH after 12z given uncertainty.
Outlook...
Monday Night: VFR. NO SIG WX.
Tuesday: VFR. Slight chance FZRA.
Tuesday Night: Mainly VFR, with local IFR possible. Chance SN,
Chance FZRA.
Wednesday: MVFR. Chance SHSN, Chance SHRA, Chance FZRA.
Wednesday Night: Mainly MVFR, with local IFR possible. NO SIG WX.
Thursday: Mainly VFR, with local MVFR possible. Chance SN.
Thursday Night: MVFR/IFR conditions possible. Definite SN, Slight
chance RA.
Friday: Mainly MVFR, with local IFR possible. Chance RA, Chance
SN, Chance SHSN, Slight chance SHRA.
&&
.BTV WATCHES/WARNINGS/ADVISORIES...
VT...None.
NY...None.
&&
$$
SYNOPSIS...Taber
NEAR TERM...Hastings/Taber
SHORT TERM...Kutikoff
LONG TERM...Kutikoff
AVIATION...Hastings/Taber
Area Forecast Discussion
National Weather Service Chicago/Romeoville, IL
820 PM CST Sun Jan 15 2023
.UPDATE...
Issued at 820 PM CST Sun Jan 15 2023
A couple of minor tweaks to the forecast this evening.
First, overcast skies and gusty winds have caused temps to level
off and even creep up a degree in spots this evening. Warm air
advection only forecast to strengthen overnight, so have adjusted
temps up just a bit tonight, generally expecting near steady
temperatures through the night.
Also, slow onset of pops just a bit late tonight. Monday morning
still looks quite wet, but does look like steady rain should think
out to more scattered showers and probably drizzly tomorrow
afternoon. The 00Z HRRR continues to show a tongue of very weak
instability nosing into our western CWA later tomorrow afternoon.
This axis of instability, already quite weak (a couple hundred
j/kg of MUCAPE), should weaken further as it progresses east
across the CWA and eventually gets pinched off my mid evening.
Delayed the start of slight chance thunder until 21Z over western
CWA, then spreading east.
Rest of the forecast on track.
- Izzi
&&
.SHORT TERM...
Issued at 126 PM CST Sun Jan 15 2023
Through Monday night...
Forecast concerns include thunderstorm chances Monday afternoon/
evening, winds through Monday afternoon and rain start time
tonight/Monday morning.
Low pressure will move northeast from the central Plains tonight
to the northern Great Lakes by Tuesday morning. Rain is expected
to develop late tonight and continue through Monday afternoon
across the local area. There may be some showers or sprinkles
after midnight tonight, mainly across the northwest half or so of
the cwa. This activity appears like it would be fairly light and
have a slow increase through chance pops during this time period.
The steadier rain is expected closer to daybreak across the west
and perhaps not until mid morning across the Chicago metro area
with a 4-6 hour period of at least light rain, perhaps steady rain
expected. Showers and perhaps some drizzle will continue through
the afternoon and into Monday evening.
Warmer air begins to spread across the area Monday afternoon and
its possible the highs for the day will be reached Monday evening,
perhaps upper 40s for most of the area, with lower 50s possible
south. There will be a narrow ribbon of weak instability that
moves across the area during this time period and its possible
that a few thunderstorms may develop. Confidence is fairly low and
coverage may end up isolated but slight chance thunder mention
still warranted for the entire area, with perhaps a better chance
across the western cwa. Severe potential looks very low and
perhaps west of our area if it were to occur, but trends will
still need to be monitored.
South/southeast winds currently gusting into the 30 mph range will
likely continue into this evening, with a gradual decrease
possible overnight, though gusts are likely to prevail for much of
tonight. Southerly winds will remain gusty on Monday, possibly
into the 30 mph range again but there remains some uncertainty,
especially into the afternoon.
There is also some potential for at least patchy fog on Monday,
especially across northern and northwest IL. The stronger winds
noted above adds uncertainty to any possible fog. Its possible
the rain or possible rain/drizzle combo may by itself lower
visibilities without actual fog developing but added patchy fog
across northwest IL for Monday afternoon. cms
&&
.LONG TERM...
Issued at 144 PM CST Sun Jan 15 2023
Tuesday through Sunday...
At the start of the long term period on Tuesday morning, we`ll be
on the cyclonic shear side of a robust quasi-zonal jet streak as a
series of vort maxes pivot around the base of a broad upper low
across the Great Lakes. It looks like we`ll retain just enough
saturation, combined with persistent DCVA from incoming
perturbations, to hold onto a chance for continued precipitation,
at least through Tuesday morning. Deeper saturation will have been
shunted well east of the area, with profiles looking like they`ll
be more supportive of drizzle or light rain although it may be
just cold enough on Tuesday morning for some snow mixing in.
Otherwise, breezy west to northwest winds will develop as a modest
region of CAA sweeps through. Looks pretty quiet Tuesday night
into Wednesday.
Primary attention during the long term forecast is on the
Wednesday evening - Thursday time period as a robust storm system
ejects across the Plains and across the Great Lakes region. While
there`s still a good deal to work out on the smaller-scale (i.e.
lots of potential complications owing to double/triple-barreled
nature of the surface low reflection, widespread convection across
the ArkLaMiss, etc.) we`re starting to see better multi- model
consensus on the general 850 low tracks which have taken a
northward and warmer jog across the entire guidance suite.
With significant upper divergence within a coupled jet structure
arcing across central Plains Tuesday night, rapid lee side
cyclogenesis is forecast to occur across the Oklahoma/Texas
Panhandle region on Wednesday morning. This will result in a
fairly intense initial surface low which will slingshot a warmer
airmass northward across our region through the day with 850 mb
temperatures headed above 0 C almost area-wide during the
afternoon. While additional wobbles in the synoptic scale features
are likely at this range, the latest multi-model consensus 850 mb
low track now seems to be focusing along something like a Kansas
City to Chicago line along this tightening baroclinic zone. This
type of track would tend to focus the heaviest snow threat across
far northern/northwest Illinois and into Wisconsin. Additionally,
the upper pattern seems to be favoring a general neutral tilt with
things gradually deamplifying with eastward extent. As a result,
noting that most model guidance is now blasting the system dryslot
northbound through pretty much our entire area by as early as
late Wednesday night.
While there`s obviously plenty of time for things to change (and
we`ve seen plenty of southeast shifts with low tracks this
season), seems to be a meaningful trend today with entirety of the
guidance suite shifting in tandem (UKMET included). This includes
a faster onset of initial precipitation, possibly as early as
Wednesday afternoon across central Illinois, spreading north
across the region through the evening. Instability upstairs is
quite impressive initially, but if latest guidance pans out,
deeper saturation will be ephemeral as no system pivot/negative
tilt arrives in time to halt its poleward advance. As a result,
there`s a maybe 6 hour period where instability, deeper
saturation through the DGZ, and strong ascent overlap across
immediately north and west of the 850 mb low track (far northern
Illinois). Could very well envision a brief period of convective
snowfall rates in this scenario, but this would end abruptly with
p-type transitioning to drizzle/snizzle by Thursday morning with
a mainly rain to drizzle event south of I-80. As it stands right
now, the main area of concern we have for winter-related travel
impacts is roughly along and north I-88 into Thursday morning.
The core of the upper low transits overhead into Thursday
afternoon, and with steep mid-level lapse rates floating around,
could see things transition to snow and rain showers. Lack of more
potent CAA suggests temperatures may remain at or above freezing
during this period.
Beyond this system, a colder (though not exceptionally cold for
late January) and active pattern looks to continue heading into
late January per solid ensemble consistency out in the medium-long
range.
Carlaw
&&
.AVIATION...
For the 00Z TAFs...
VFR conditions tonight will give way to lowering CIGS Monday
morning after rain begins. As rain continued during the morning,
look for CIGS expected to build to IFR by late morning or early
afternoon. Rain is likely to taper off to drizzle during the
afternoon with light fog and IFR conditions likely and some
potential for LIFR CIGS during the afternoon and early evening.
Could see some ISOLD to WDLY SCT SHRA during the evening in
advance of a cold front.
Gusty southeast winds expected into the evening. Frequency of
gustiness could wane this evening, which if gusts cease could
result in a threat of LLWS as winds a couple thousand feet off the
deck increase to around 50kt from the southwest this evening.
South-southeast winds around 15kt expected Monday, with
considerable uncertainty regarding potential for gusts. Maintained
gusts in the TAFs, but with lowering CIGS and more stable
conditions the frequency of gusts could be rather sparse Monday.
- Izzi
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...None.
IN...None.
LM...Small Craft Advisory...nearshore waters until 6 PM Monday.
&&
$$
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Area Forecast Discussion
National Weather Service Marquette MI
536 PM EST Sun Jan 15 2023
.SHORT TERM...(Through Tonight)
Issued at 319 PM EST SUN JAN 15 2023
Water vapor this afternoon reveals a shortwave moving into northern
Ontario on the back edge of the exiting upper ridge, with RAP
analyses indicating a 40 to 50kt low level jet draped over the UP
and Lake Superior. Mid to upper level clouds continue to sweep
through the area as this shortwave moves northeastward, but the back
edge of this area of clouds is already working into the southwestern
UP with a brief window of clearing for the late afternoon and
evening. As we are past peak heating, this should not have much of
an impact on temperatures. That said, temperatures have been coming
in slightly warmer than previously expected even under these cloudy
skies, with most spots topping out in the mid and upper 30s. In the
interior-western portions of the UP, we may still only peak in the
lower to mid 30s.
Otherwise, windy conditions continue today into the first half of
the night with the tight pressure gradient in place slackening
slightly overnight. Winds over most of the UP continue to gust to
around 20 to 30mph. Some higher gusts around 35 to 40mph have been
observed at Munising and Grand Marais, with the downsloping areas
along the Superior shoreline from Marquette to Grand Marais seeing
the highest potential for stronger gusts to 40 to 45mph until winds
start to slowly fall back later this evening.
The ridge continues to shift eastward out of the area overnight. A
tightening Colorado Low is already apparent on water vapor imagery,
and this should start to head into the area by the early hours of
Monday. Clouds increase again through the night, but precipitation
will largely hold off until Monday morning with simulated
reflectivity largely delaying the onset until after sunrise. If we
can get any precipitation before 12Z, it will be quite light.
Soundings remain fairly dry aloft, so precipitation may start off
more as a mix of light snow/flurries and freezing drizzle before
changing more over to rain/snow/freezing rain after 12Z. Some patchy
icing would not be out of the question, but otherwise very little by
way of snow or ice accumulations is expected. Otherwise, expect lows
generally in the upper 20s the lower 30s, with the chillies spots in
the interior west.
.LONG TERM...(Monday through Sunday)
Issued at 353 PM EST SUN JAN 15 2023
With respect to the large scale pattern evolution thru the end of
Jan, the last 24hrs of medium range guidance show no significant
changes from the guidance viewed yesterday. There are some important
trends noted with regard to low pres tracking to the Great Lakes
later this week. More on that later. For the first 14 days of Jan,
avg temps across Upper MI are running 8 to 12F degrees above normal,
and temps this week will likely maintain these anomalous values. The
"warm" pattern has been a result of a series of shortwaves
progressing across the N Pacific and then downstream across N
America. This has resulted in significant pcpn occurring across CA
and has forced Pacific air masses e across the U.S. In addition, the
lack of any sustained ridging across western N America/just offshore
has prevented any buildup and expansion of Arctic air to the n in
Canada. The pattern across N America this week will feature more of
the same, but the beginnings of a pattern change are evident late
week, something medium range guidance has been hinting at for about
a week now. Mid-level ridging will begin to develop vcnty of the W
Coast late this week. This in turn will force troffing to develop
downstream across central N America next week, leading to a trend to
colder weather for Upper MI. ECMWF/CMC/GFS ensembles continue to
suggest the western ridging/positive height anomaly will then
retrograde toward the Aleutians by the end of the month, which would
in turn pull the central N America trof axis w toward the western
U.S., but with a positive tilt to Hudson Bay. Overall, this should
support at least a period of blo normal temps heading toward the end
of this month and into early Feb. There may be an opportunity to get
a surge of bitter cold arctic air into the Great Lakes, probably at
the end of next week/early the following week, depending on how
amplified the western ridge initially becomes before retrograding.
Then, with the pattern retrograding, the coldest air should tend to
settle toward western Canada/the northern Rockies and Northern
Plains, but Upper MI should remain under somewhat blo normal temps.
As for pcpn this week, 2 waves impacting CA will go on to produce
low pres systems that will track to the Great Lakes/Ohio Valley
region. The first will track farthest n, affecting Upper MI Mon/Tue
with a mix of ptypes. The second will take a track farther s,
reaching the Great Lakes/Ohio Valley Thu, but ECMWF and its
ensembles have made a notable northward trend over the last 24hrs.
Ptype will be snow with the second wave, and given the ECMWF trends,
there is now a growing potential that a mdt snowfall, maybe
significant, will be in the offing for at least portions of Upper
MI. At the end of the week, the beginnings of the pattern change
will send a northern stream shortwave to the Upper Great Lakes,
providing a chc of -sn.
Beginning Mon/Tue, shortwave that moved across CA last night/early
today will quickly move to the Central Plains by early Mon morning,
then to the western Great Lakes by Tue morning. At the sfc, low pres
will track from se CO to northern Lake MI, but with the mid-level
wave not particularly well-defined or strengthening, it won`t become
a classic hvy pcpn producing winter storm. With the "warmth" already
over the area, a mix of ptypes are expected. Initially, evaporative
cooling may cool the column sufficiently for some snow to mix with
rain Mon morning, and with sfc temps around freezing in many areas,
especially high terrain nw half, fzra will be an issue as well. WAA
will then win out during the day, supporting just rain as ptype, but
column could remain just cold enough for some snow nw half, and sfc
temps might also hold around freezing over high terrain to keep some
fzra in the picture. The CMC does keep the column sufficiently cold
for mostly just snow on Mon, but it is an outlier among all the
model guidance and will be disregarded. Based on where fzra/icing
will probably cause at least some travel issues Mon morning, opted
to issue a winter wx advy for Dickinson/Marquette w to southern
Houghton/Ontonagon/Gogebic counties. A transition to snow from nw to
se will occur later Mon night into Tue as heights fall/column cools.
FZRA may also occur during the transition, but that seems less
likely given the column cooling scenario. Given the mix of ptypes
and lack of really organized/focused forcing throughout, significant
pcpn with this system is not expected. In the end, there may be a
few inches of dense/wet snow accumulation across portions of the
fcst area, mainly w to n central. Ice accumulation from fzra should
be minor Mon morning. While the system pcpn exits on Tue, low-level
northerly cyclonic flow and 850mb temps down to around -7C should
support some light lake enhanced/upslope snow into Tue night.
Sfc high pres will then ridge s into the area on Wed. While it
should be a dry day, it will be another day of low clouds as has
been so common in recent weeks. There is a slight potential that
there could be some upslope -fzdz in the high terrain favored by n
winds on Wed given the shallow saturated/near saturated look of fcst
soundings.
The next shortwave arriving in CA on Mon will reach the Central
Plains on Wed, then the Great Lakes on Thu. ECMWF and its ensembles
have made a solid northward trend, beginning with the 18z run
yesterday. The 06z/12z runs suggest a low track now from se CO to IL
to northern Lwr MI as opposed to se Lwr MI/far southern Ontario.
Probabilities of accumulating snowfall have followed suit with
potential axis of greatest snowfall now running from northern IA to
the northern Lake MI shore, including an extension into n central
Upper MI. While the CMC/GFS and accompanying ensembles are still
farther s, there are some slight northward trends noted on the 12z
runs. The 4 run ECMWF trends at this time range are important to
consider, and so this fcst issuance will trend solidly in that
direction. While confidence is still low, a headline snow event is a
decent possibility across at least the se half of Upper MI Thu,
including n central Upper MI due to cyclonic ne upslope flow during
the synoptic forcing. While there isn`t much caa as the system
departs, cyclonic low-level northerly flow backing nw and marginally
low enough 850mb temps should support some LES off of Lake Superior
Thu night into maybe Fri morning.
There is some model agreement for a northern stream shortwave to
approach over the weekend, providing a chc of -sn at that time. In
addition, one last wave moving onshore over the W Coast midweek will
drop to the Southern Rockies/Plains this weekend. Should some
interaction with any of the northern stream waves occur late
weekend/early next week, a third low pres would lift toward the
Great Lakes. Right now, it appears unlikely that the low would
affect Upper MI if some interaction does occur.
&&
.AVIATION...(For the 00Z TAFS through 00Z Monday evening)
Issued at 536 PM EST SUN JAN 15 2023
VFR prevails into Mon morning. Ceilings gradually lower ahead of
chances for precipitation into early Monday. Wintry precipitation,
possibly starting as freezing rain or a mix of snow and freezing
rain, moves into IWD by 12Z and to CMX and SAW around 13-15Z, then a
change mainly over to rain is expected during the late morning
hours. Ceilings lower to MVFR into Monday morning, with all sites
falling to IFR/LIFR by Mon afternoon.
&&
.MARINE...(For the 4 PM Lake Superior forecast issuance)
Issued at 353 PM EST SUN JAN 15 2023
Tight pres gradient btwn a low pres trof to the w and sfc high pres
ridge from Quebec to the Upper Ohio Valley will result in southerly
gales to 35-40kt this evening across much of the e half of Lake
Superior, particularly in the middle portion of the e half from
Granite Island to Grand Marais northward. Stannard Rock had a few
gusts to 40-45kt earlier today, and there may yet be a few gusts
just above 40kt this evening at the highest obs platform. Across
western Lake Superior, expect southerly winds gusting up to 20-25kt
tonight. During Mon, winds across Lake Superior will back se to e.
While gusts will generally be under 20kt w, expect gusts of 20-30kt
e. During Mon night, expect winds of 15-25kt, but there may be
higher gusts to around 30kt around Whitefish Pt. As low pres tracks
ene across northern Lake MI/northern Lwr MI Mon night/Tue, winds
will back northerly for Tue/Tue night and increase with gusts to 25-
30kt across much of the lake. Winds will fall back to around 20kt on
Wed, then increase on Thu from the ne as low pres tracks ne to the
Great Lakes. Gusts to 25-30kt are expected at that time.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
Upper Michigan...
Winter Weather Advisory from 7 AM to 1 PM EST Monday for MIZ002-
004-005-009>011-084.
Lake Superior...
Gale Warning until 1 AM EST Monday for LSZ249-250-266.
Lake Michigan...
None.
&&
$$
SHORT TERM...LC
LONG TERM...Rolfson
AVIATION...07
MARINE...Rolfson
Area Forecast Discussion
National Weather Service Pocatello ID
810 PM MST Sun Jan 15 2023
.UPDATE...The back edge of the snow moved northeast as anticipated
this afternoon, but has since nearly stalled. Snow continues north
and east of a line from Mud Lake to Blackfoot to Soda Springs to
Preston. Allowed the Winter Weather Advisory to drop from zones just
south of Pocatello to Malad. Kept the Bear River Range and Bear
Lake area going through the rest of the evening as transportation
web cams still show snow ongoing with potential travel difficulties.
HRRR is still bullish on the snow band dissipating by midnight,
but latest NAM holds on to an area of snow from near Palisades all
the way north to the MT line. This area of snow should linger for
the remainder of the night. DMH
&&
.PREV DISCUSSION... /issued 209 PM MST Sun Jan 15 2023/
SHORT TERM...Tonight through Monday night.
A diffuse upper level trof is moving slowly through eastern Idaho
with an associated cold front which has moved through the state.
Widespread light snow had been falling throughout today in the
Snake River Plain and southern and eastern mountains. Generally 1
to 3 inches has fallen today with temperatures very near freezing
on either side of it so have had only minor travel impacts but
could see some freezing on roads especially after sunset. Winter
weather advisories remain in effect for the southern and eastern
mountains with the Upper Snake Highlands in effect through tonight
and the southern and southeast mountains expiring either at 5 PM
or 8 PM tonight. An additional 2 to 5 inches of snow are possible
in the Upper Snake Highlands tonight and Monday with 1 to 3 in the
southeast highlands and an inch or less in the Snake River Plain.
Will be colder overnight tonight with lows in the teens and 20s
with some single digits in the STanley area and highs Monday.
Highs Monday ranging from the mid 20s mountains to mid 30s
valleys. Expect snow to end in the Island Park area late Monday
with snow from the next upper low maybe moving into the extreme
southern highlands along the Utah border late Monday night.
GK
LONG TERM...TUESDAY THROUGH NEXT SUNDAY...
An active wx pattern continues this week into next weekend, with
fairly steady temps (perhaps cooling slightly with time) running 5-
10 degrees shy of mid-Jan norms. Our next system impacts the region
in the Wed night-Thu night period, with temps supporting all snow.
The ECMWF continues to bring this shortwave (closing off into a mid-
level low) right across SE Idaho with attendant higher accums, while
the GFS/Canadian close that low off further south/west and thus are
much drier, so some uncertainty continues. The latest NBM, with QPF
adjusted by WPC, has trended a touch drier, with accumulations of a
dusting to 3 inches across the region. After a break Fri/Sat,
another system arrives Sat night/Sun with another chance of at least
light widespread snow. At this juncture, aside from the usual travel
slick spots, neither systems looks to be stunningly impactful. 01
AVIATION...
TAFs continue to be quite a challenge, as they often are during
winter mixed precip systems. The best chance for continued LIFR cigs
is over the next few hours at KPIH and KIDA as mixed rain/snow
continues to slowly trend ENE. Should see cigs/vsbys come up
starting this eve as precip pulls away. We`ll also see winds tick up
this afternoon into tonight as well, although nothing gusting higher
than 25kts. Later tonight into Mon AM, SOME guidance including the
NBM and MOS are leaning into fog/low stratus issues, while some
other guidance including the HRRR is less pessimistic at the
immediate terminals. Given recent widespread precip which should
keep the sfc quite moist, we`re leaning into the fog/stratus
scenario for now, but we note confidence is quite low (and if the
winds stay up, this tends to not support much in the way of fog).
Further west, KBYI and KSUN are most likely to continue trending
back into VFR from this point forward with precip done...most models
are not developing fog at KBYI (gusting winds this eve though), and
the normal diurnal NW downvalley flow at KSUN should help keep
things drier. Further east, the period of greatest impacts is just
getting started at KDIJ, with long-duration IFR cigs/vsbys likely
arriving by 03z/8pm this eve if not earlier (the trend that
direction has already begun in sfc obs as precip spreads in). Will
continue to monitor trends/timing and amend as needed. 01
&&
.PIH WATCHES/WARNINGS/ADVISORIES...
Winter Weather Advisory until 11 PM MST this evening for IDZ060-
061.
Winter Weather Advisory until 5 AM MST Monday for IDZ064-066.
&&
$$
Area Forecast Discussion
National Weather Service Las Vegas NV
700 PM PST Sun Jan 15 2023
.SYNOPSIS...The next system will move into the area tonight and
Monday bringing another round of heavy mountain snow and wide
spread valley rain to the area. Dry, cooler weather is expected
for the remainder of the week, however a system dropping in from
the north on Thursday could result in light showers across parts
of the area.
&&
.UPDATE...Starting to see some light showers develop across the
western Mojave Desert ahead of next shortwave coming into
California. HRRR indicates showers will continue to develop and
spread east-northeast into southern Nevada and northwest Arizona
late this evening through Monday morning. HRRR suggests lines of
showers and isolated thunderstorms developing under more unstable
air mass tomorrow afternoon into the evening. Most of the QPF is
expected to fall in the next 24-30 hours with lighter wrap around
precipitation lingering in parts of southern Nevada and northwest
Arizona into Tuesday. Expecting some stronger winds to develop
within the Mojave Desert tomorrow. Winds back off some tomorrow
night only to increase and shift from the west-northwest with the
cold frontal passage. Not committed to any wind headlines yet but
will take a close look as I work through the upcoming forecast
for tonight. See no adjustments needed at this time.
&&
.PREV DISCUSSION...159 PM PST Sun Jan 15 2023
.DISCUSSION...Tonight through Tuesday.
The next storm to bring impacts to our area begins tonight with
heavy snow getting underway after 10 pm this evening in the
Sierra and after 4 am Monday elsewhere. Multiple areas are under
Winter Storm Warnings for expected heavy snowfall overnight into
Monday. Upgraded the Winter Weather Advisory in effect for Mohave
County to a Winter Storm Warning primarily based on precipitation
amounts forecast for the Northwest Plateau. Lesser amounts are
expected across central Mohave County including the Hualapai
Mountains where 3-6 inches are expected on Hualapai Road with
higher amounts at Hualapai peak. This system is expected to bring
widespread valley rain to the area as well - generally ranging
from a few hundreths up to 1.50 inches. For the Las Vegas area,
current forecast amounts range from 0.10-0.50 inches with locally
higher amounts on the far west side.
The other concern with this system is gusty wind conditions across
the deserts. Borderline advisory level winds are forecast for the
Western Mojave Desert and the Morongo Basin area Monday afternoon.
No headlines yet but they could be needed at some point.
Showers linger across parts of the area Monday night and even into
Tuesday before dry conditions set in on Wednesday and continue
through the weekend. High pressure building off the coast will
essentially cutoff any AR moisture from reaching the coastal
states for an extended period of time. The position of the high
however will open the door for colder systems dropping into the
area from the north which is the case for late Wednesday night
and Thursday. Precipitation chances with that system are forecast
to increase but amounts will generally be light. There is also
some uncertainty tied that this system regarding whether it will
be an drier, inside slider as depicted by the EC ensemble
solutions or the slightly wetter GEFS/GEPS solutions.
Beyond Thursday, dry weather is forecast Friday through the
weekend. Temperatures are expected to bottom out Thursday and
Friday around 10 degrees below normal before rebounding slightly
over the weekend but still remaining well below normal.
&&
.AVIATION...For Harry Reid...South to southwest winds gusting to 25
kts at times will continue through the late afternoon before
decreasing overnight. VFR conditions are expected through this
afternoon, but CIGs will lower once again overnight, falling to 3 to
5 kft by 2 AM as scattered showers move into the terminal area. The
threat of showers will continue through Monday afternoon before
ending in the evening. While not included in the latest TAF
package, CIGs may fall below 3 kft tomorrow morning and afternoon in
heavier precipitation. An isolated thundershower is also possible
tomorrow afternoon, most likely between 10 AM and 4 PM.
For the rest of southern Nevada, northwest Arizona and southeast
California...South to southwest winds are expected at regional TAF
sites into this evening as the area remains between two storm
systems. VFR conditions are expected through the afternoon, but
CIGs will lower overnight as the next system approaches. Most sites
will see CIGs fall to 3 to 5 kft by tomorrow morning as rain and
snow showers spread across the area, although CIGs lower than 3 kft
will be possible in areas of heavier precipitation. A few isolated
thundershowers are also possible Monday afternoon, mainly across
southern Nevada and northwest Arizona.
&&
.SPOTTER INFORMATION STATEMENT...Spotters are encouraged to report
any significant weather or impacts according to standard operating
procedures.
&&
$$
UPDATE...Pierce
DISCUSSION...Salmen
AVIATION...Planz
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