Forecast Discussions mentioning any of
"HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 01/20/25
Area Forecast Discussion
National Weather Service Binghamton NY
941 PM EST Sun Jan 19 2025
.SYNOPSIS...
Snow continues to fall east of I-81, and should remain across
the area into the early overnight hours. Arctic air mass moves
in behind the system with much colder temperatures settling in
tonight. Pattern will continue through the first half of the
week with overnight lows and wind chills falling below zero.
&&
.NEAR TERM /THROUGH MONDAY/...
930 PM Update...
The majority of the snow has left Luzerne and Lackawanna
counties so the Winter Storm Warning has been cancelled. The
Advisory remains in effect for Wyoming and Susquehanna counties
as snow showers have started to re-develop over the area so we
will keep the advisory up and re-evaluate later.
Snow will remain east of I-81 in NY for the next few hours
before finally lifting to the NE by midnight or so. Small
adjustments were made to PoPs, winds, and sky based on current
trends. The rest of the forecast remains on track.
550 PM Update...
A band of heavy snow is currently moving through Sullivan and
Pike counties, dropping snow at 2in per hour and causing most
of the roads in the area to become quickly snow covered. Dry and
cold air continues to keep the snow from reaching too far west
into CNY and the Southern Tier, as shown by dewpoint depressions
near Binghamton, Ithaca and Norwich are between 15 to 18
degrees. The forecast remains on track with the vast majority of
the snowfall expected to remain east of I-81, closer to the
Catskills. Minor updates were made to PoPs, winds and sky cover
based on radar trends and updated guidance.
330 PM Update...
Coastal low pressure system continues to move over the northeast
with snow showers mainly over Northeast PA and the Catskill
region of NY this afternoon. Best forcing continues to remain
east of the area with frontogenesis over the Poconos and
Catskills region. This allowed steadier snow to fall late
morning though the afternoon. Snow totals were shifted
eastwards this update as this system has struggled to reach the
Southern Tier portion of NY. A blend of HRRR and WPC was used
to scale back on the extent of QPF. A tight gradient is
expected in terms of totals, with at least an inch of snow
expected on the edge of this system. Snow showers will continue
through early evening. No changes were needed for Hazards, a
Winter Storm Warning and Winter Weather Advisory remains in
effect through 1 AM Monday morning. If system moves out sooner,
hazards may be lifted sooner.
As the low shifts eastwards, the arctic front moves in with
temperatures falling into the single digits. Winds will range 5-12
knots overnight allowing wind chills to fall below zero. With lake
temperatures ranging in the 40s and much cooler air racing over
the region, lake effect showers will develop tonight. DGZ
continues to be surfaced based, therefore not expecting much of
an inland extent with these showers. Showers overnight should
focus over the finger lakes region with only a few tenths of an
inch expected in terms of accumulation.
A cold start is expected Monday morning with temperatures in the
single digits along with breezy conditions continuing. Highs are
only expected to climb into the mid to upper teens with a few spots
in northeast PA in the low 20s. Wind chills are looking to stay at
or below 0 for most of the day. With a little bit of day time
heating with breaks of sun between lake effect clouds, the lake
effect off of both Ontartio and Erie will be able to extend farther
inland. Showers will initially focus over the northern portion of
our region before shifting into central NY by the afternoon.
Expecting light accumulations with up to a few tenths of an
inch.
&&
.SHORT TERM /MONDAY NIGHT THROUGH WEDNESDAY NIGHT/...
330 PM Update:
A very cold airmass will be in place Monday night with 850mb
temperatures around -23C. Skies will also be mostly clear for
the majority of the area, besides some lake effect clouds across
northern Oneida County. Low temperatures are expected to be
right around zero degrees, and a few degrees below zero in some
spots. In addition, with somewhat breezy conditions (wind gusts
up to 20-25 mph), wind chills will be in the -10s for most of
the area, with some isolated spots in the -20s. Cold Weather
Advisories will likely be needed at a later time, but after
coordinating with our neighboring WFOs to the east, opted to
hold off at least one more forecast cycle with winter weather
headlines ongoing through this evening. There will also be lake
effect snow showers for areas north of the NY Thruway corridor,
but with a southwesterly flow, not expecting snow to make it
south of there.
Same story for the daytime hours on Tuesday and Tuesday night
with very cold temperatures. Highs for parts of the area will
likely not even get out of the single digits. Even areas that do
get above single digit highs will only see temperatures top out
in the lower to mid teens. There will also still be some lake
effect snow showers for areas north of the NY Thruway, but
otherwise precipitation-free weather is expected with partly
sunny skies. Lows Tuesday night may actually be a bit colder
than Monday night (a few degrees below zero for most of the
area), but with lighter winds, wind chills will be very similar.
High pressure will be in control of the weather on Wednesday
with mostly sunny skies. However, with the arctic airmass still
in place, highs are again expected to only be in the single
digits to lower teens. Then one more night of subzero (or near
zero) temperatures is expected Wednesday night.
&&
.LONG TERM /THURSDAY THROUGH SUNDAY/...
330 PM Update:
A moderating trend in temperatures is expected to finally begin
on Thursday, but it will still remain cold with highs only in
the upper teens to mid 20s. This moderating trend in
temperatures will then continue through the remainder of the
week with highs in the 20s on Friday and Saturday, then
approaching (or even exceeding) the freezing mark on Sunday.
Otherwise, the weather pattern looks to be relatively quiet
during the long term period with a mainly zonal flow. Subtle
shortwaves may occasionally bring some snow showers to the area,
but timing of these shortwaves are very uncertain.
&&
.AVIATION /03Z MONDAY THROUGH FRIDAY/...
Mainly VFR at all NY TAF sites with winds generally 10 knots or
less. A few scattered snow showers will move through the region
after 09Z tonight gradually shifting northward from 12-16Z. Any
restrictions look fairly brief at this time. Highest coverage
of snow showers should be around KSYR and KRME after 16Z Monday.
Outlook...
Monday through Wednesday...Lake effect snow showers and
associated restrictions possible, especially for KSYR-KRME.
Thursday and Friday...Mainly VFR.
&&
.BGM WATCHES/WARNINGS/ADVISORIES...
PA...Winter Weather Advisory until 1 AM EST Monday for PAZ039-043.
Winter Storm Warning until 1 AM EST Monday for PAZ040-048-072.
NY...Winter Weather Advisory until 1 AM EST Monday for NYZ057.
Winter Storm Warning until 1 AM EST Monday for NYZ062.
&&
$$
SYNOPSIS...ES
NEAR TERM...ES/JTC
SHORT TERM...BJG
LONG TERM...BJG
AVIATION...AJG/BJG/MWG
Area Forecast Discussion
National Weather Service Goodland KS
415 PM MST Sun Jan 19 2025
.KEY MESSAGES...
- Extreme Cold Warning and Cold Weather Advisories are in place
tonight across most of the area as wind chills may fall as low
as 30 below especially across Yuma and Dundy counties.
- An early morning light powdery snowfall will come to an end
Monday followed by high temperatures struggling to get out of
the single digits for the entire area.
- Extreme Cold Watch remains for the entire area Monday night
and into Tuesday morning; potential coldest night of the
event.
- Near seasonable temperatures and conditions are forecast after
Tuesday.
&&
.SHORT TERM /THROUGH TUESDAY NIGHT/...
Issued at 129 PM MST Sun Jan 19 2025
The main portion of the surface high starting to move to the east
allowing for some westerly downsloping winds across the west to
develop. These winds however are not enough to overcome an air
mass ranging from -7 to -13 850mb temperatures and a snow pack
across eastern Colorado as highs look to top out today in the
mid teens to low 20s across the area.
Tonight, clouds are forecast to start increasing during the early
evening hours as a weak surface trough moves through the area; with
the passage of this trough another shot of much colder air spills
into the area tonight. Starting with the snow chances, overall the
snow chances don`t look as good as they did 24 hours ago due to
weaker lift and the presence of some dry air at the surface
lingering around. There does look to be a window from roughly 10pm
to 2am MT for locales along and north of Interstate 70 to see some
light snow occur but with the very dry air in place minimal to no
snow fall is expected with this. As this system continues to work
its way south the lift does increase a little bit which is what is
leading to the higher chances for snowfall with the relative best
chances looking to be along and south of Highway 40. For the entire
event around a half inch of snow looks most likely for Greeley and
Wichita counties due to the better lift and across the higher
elevations of Yuma, Kit Carson and Cheyenne counties in
Colorado.
Now to the temperatures and the wind chills, the hazardous wind
chills do look to return again but may be a little delayed due to
the cloud cover in place helping keep temperatures from falling
to much at first. Winds as the newest round of cold air spills
in is forecast to increase with sustained winds of 15-20 mph
which will initially start the decline in wind chills, around
3-5am MT drier air will begin to push in which will bring an end
to the cloud cover allowing for the temperatures to begin to
fall. With the anticipated clearing and breezy winds concerns
for Extreme Cold Warning conditions with wind chills of -25
below zero are in place with the highest confidence currently in
Yuma and Dundy county where I have issued the warning for. I
was debating adding in Kit Carson county as the snow pack last
night wound up dropping temperatures more than originally
expected along with locales falling as low as -28 wind chills;
the reason I help off was due to the concern for cloud cover
lingering to long. Elsewhere, with the exception of Norton and
Graham counties a Cold Weather Advisory is in place as the breezy
winds will be the main driver for the wind chill concerns. The
winds for Norton and Graham at this time do not appear to be
strong enough to warrant wind chill concerns. There is the
potential that cloud cover will erode earlier or move out quicker
(10%)if this occurs then temperatures and wind chills will fall
even more so with the concern for -35 to even -40 wind chills
across Yuma and Dundy county and -25 wind chills further south.
Will relay on to the next shift to keep an eye on any trends for
this occur. If the cloud cover does hold on a little longer (10%)
then those in the Cold Weather Advisory should continue to see at
least 15 below wind chills as the winds will be the main driver;
Yuma and Dundy counties however may not reach the 25 below for
warning criteria.
Monday, the cold air will continue to spill into the area
leading to most locations not exceeding the single digits for
high temperatures. Winds will continue to be breezy throughout
the day gusting 20-30 mph which does lead to the concern for
Cold Weather Advisory criteria continuing to be met through the
whole day especially for western portions of the area. Will
continue to see what newest guidance suggests for wind and
temperatures but a potential time extension for the Advisory may
be needed. There may be elevated fire weather threat across the
east as very dry dew points in the teen to 20 below range move
in and winds gusting around 30 mph. With the current anticipated
colder temperatures in place humidity values in the mid to
upper 20s are currently forecasted. I did nudge temperatures up
a tad bit if mixing for the breezy winds can bring down some
slightly "warmer" temperatures. If this doesn`t happen then some
record coldest high temperatures may be in jeopardy of being
broken Monday.
Monday night continues to be coldest of the entire event. As winds
are forecast to be lighter, clear skies and very very dry dew points
down as low as -20F remain forecasted will increase the concern for
very strong radiational cooling potential. I continue to go with
some of the coldest guidance but I do have some concern that it
still may not be cold enough especially if radiational cooling
is strong enough. If this is the case then some record lows may
be in jeopardy of being broken. I did continue the Excessive
Cold Watch for the entire area for Monday night as wind chills
remain forecasted below -20F for the entire area. Throughout the
night winds will slowly become more SSW will slowly push out
the cold air mass as some locales especially across the west
low temperatures for the night may occur before midnight. Into
Tuesday a warming trend is forecast to ensue as high
temperatures above freezing are forecasted. 850mb temperatures
do support higher than forecast temperatures but I have concern
about the snow pack across eastern Colorado moderating that a
bit so did continue with a relative cooler trend in guidance.
Tuesday may also see some near critical to locally critical fire
weather across the east as the very dry dew points remain along with
the warming temperatures. Humidity values are currently
forecast in the low to mid teens but there is potential for wind
gusts of 25-35 mph as the RAP shows a 40 knot 850mb jet nudging
into the area which is also supported by GFS forecast soundings
with slightly stronger mixing which the GFS typically does
excel in. So this will need to be watched for potential fire
weather highlights.
&&
.LONG TERM /WEDNESDAY THROUGH SUNDAY/...
Issued at 1238 PM MST Sun Jan 19 2025
The long term continues to favor near average temperatures and low
precipitation chances through the work week as we are forecast to
remain under northwest flow. A system and colder temperatures are
possible over the weekend.
For Wednesday and Thursday, guidance continues to favor a low
amplitude trough swinging through the Plains. With a cold front
moving through early Wednesday and a stronger height gradient,
winds are forecast to become stronger with speeds around 20-30
mph and gusts up to 50 mph. Highs are forecast to be in the 30`s
and low 40`s with lows in the teens. Temperatures could be a
bit cooler and winds a bit lighter if the trough digs more west
like some ensemble members are currently hinting at.
Precipitation chances aren`t zero, but similar to the recent
cold front, chances are low as the front is early and well ahead
of the suggested moisture advection from the north.
Friday is forecast to have some slight ridging aloft ahead of the
next upper trough. A surface low is forecast to push through the
area later in the day as the upper trough pushes into the Northern
Rockies and Plains. This will help the low level flow stay from the
south and pull warmer air into the area. Highs are forecast to climb
to near 50 as long as the system doesn`t push through too quickly.
Otherwise, cloud cover and northerly flow would keep temperatures in
the 30`s and 40`s. Currently, the area is forecast to be too dry for
precipitation as the low passes which is why precipitation chances
are currently less than 10%.
Saturday and Sunday are not very clear as another cut-off low is
forecast to develop as the main trough swings through. The
positioning of the cut-off low will determine what conditions the
area will face. Unfortunately, there is an even spread between
a more northwesterly and southwesterly cut-off low and a fair
amount of spread in how deep it gets. The overarching themes are
that temperatures should at least be a bit cooler than Friday
and there should be increased chances for cloud cover and
precipitation as we sit downstream of the cut-off low.
&&
.AVIATION /00Z TAFS THROUGH 00Z TUESDAY/...
Issued at 413 PM MST Sun Jan 19 2025
For KGLD, mainly VFR conditions through the forecast period.
Looking for some light snow chances(PROB30) from 05z-09z Monday
bringing visibility down to 4sm at times and ceilings down to
OVC015. Winds, southwest around 10kts through 05z, then
shifting northwest. By 09z Monday, north 10-15kts, increasing
to 15-25kts from 15z onward.
For KMCK, looking for VFR conditions through the forecast
period with SKC giving way to a SCT-BKN mid cloud deck from 03z
Monday onward. Winds, light/variable through 03z, then east
5-10kts. By 10z, shifting north and eventually northwest around
10-20kts from 17z onward.
&&
.GLD WATCHES/WARNINGS/ADVISORIES...
KS...Extreme Cold Watch from Monday afternoon through Tuesday
morning for KSZ001>004-013>016-027>029-041-042.
Cold Weather Advisory from 11 PM MST /midnight CST/ this
evening to 11 AM MST /noon CST/ Monday for KSZ001>003-
013>015-027>029-041-042.
CO...Extreme Cold Warning from 11 PM this evening to 11 AM MST
Monday for COZ090.
Extreme Cold Watch from Monday afternoon through Tuesday
morning for COZ090>092.
Cold Weather Advisory from 11 PM this evening to 11 AM MST
Monday for COZ091-092.
NE...Extreme Cold Warning from 11 PM this evening to 11 AM MST
Monday for NEZ079.
Extreme Cold Watch from Monday afternoon through Tuesday
morning for NEZ079>081.
Cold Weather Advisory from midnight tonight to noon CST Monday
for NEZ080-081.
&&
$$
SHORT TERM...Trigg
LONG TERM...KAK
AVIATION...JN
Area Forecast Discussion
National Weather Service Green Bay WI
520 PM CST Sun Jan 19 2025
Updated aviation portion for 00Z TAF issuance
.KEY MESSAGES...
- Wind chills of 20 to 40 degrees below zero are expected at times
through Wednesday morning. The coldest wind chills will occur
Monday night into Tuesday morning when wind chills as low as 40
below zero will be possible.
- The coldest temperatures and wind chills are forecast to occur
over north-central Wisconsin. For this area, a Cold Weather
Advisory is in effect through midnight tonight. An Extreme Cold
Warning has been issued from midnight tonight through noon
Tuesday for wind chills from 35 to 40 degrees below zero at
times.
- For central and northeast Wisconsin, a Cold Weather Advisory
remains in effect until midnight on Monday night for wind chills
of 20 to 30 degrees below zero. An Extreme Cold Warning has been
issued from midnight on Monday night through noon Tuesday for
wind chills to 35 degrees below zero.
- A warming trend will start on Wednesday which will continue into the
weekend. High temperatures ranging from 10 to 20 degrees on
Wednesday will warm into the mid 20s to low 30s by Saturday.
&&
.DISCUSSION...
Issued at 216 PM CST Sun Jan 19 2025
Short Term...Tonight and Monday
The latest RAP analysis and satellite/radar imagery show arctic
high pressure stretching from northwest Canada to the Texas Gulf
Coast early this afternoon. This arctic high continues to bring in
bitterly cold air into the region today. Wind chills this morning
fell as far as 35 below to 37 below at several locations across
north-central WI where there is 3-8 inches of snow pack.
Elsewhere, 20-30 below wind chills were observed before "warming"
to 10-20 below by midday. With only scattered cloud cover upstream
(northern Minnesota), focus of this forecast continues to revolve
around dangerous temps and wind chills.
Arctic high pressure will continue to build into the region from
the northwest tonight into Monday. Low level temps will be
comparable to this morning`s with the exception that temps will be
off to a much colder start heading into the nocturnal cooling
period tonight. As a result, trended low temperatures colder
across north-central WI. Probabilities show around a 50% chance of
reaching 35 below wind chills over north-central WI late tonight
into Monday morning. With obs reaching to 35 below this morning as
mentioned above, decided to issue an Extreme Cold Warning for
north-central WI starting at midnight. Wind chills moderate during
the day on Monday, but then fall right back to warning criteria
on Monday night.
Elsewhere, the Cold Weather Advisory will continue through Monday
evening. Very cold wind chills of 20-30 below remain expected
through then.
In terms of other weather, scattered cloud cover over northern
Minnesota is forecast to push across the area tonight. But
coverage looks sparse enough to have a limited effect on temps.
Otherwise, mostly clear skies are forecast. Highs on Monday will
range from 0-5 above over eastern WI and from 0-6 below over
central/north-central WI.
Long Term...Monday Night Through Sunday
While some deamplification will take place, the ensemble means
remain steadfast showing the northern stream having the most
influence on the sensible weather across the western Great Lakes
region. Most of the attention remains on the dangerously cold wind
chills that are forecast through Tuesday night, but there are also
light snow chances at time centered around mid-week and also next
week.
Temperatures/wind chills...The coldest air in this cold air outbreak
remains poised to move across the region from Monday night through
Tuesday morning. Forecast wind chills during this period have
remained remarkably consistent showing widespread 30 below to 40
below values during this timeframe. With surrounding offices
extending their cold weather headlines into Tuesday, will issue a
Extreme Cold Warning from midnight Monday night through noon
Tuesday. High temperatures on Tuesday will likely remain below zero
away from Lake Michigan.
Arctic high pressure will be sliding across the lower Missouri
Valley to the Ohio Valley from Tuesday afternoon through Tuesday
night. The pressure gradient will therefore remain sufficient for
breezy conditions to continue despite the core of the arctic airmass
sliding east of the region on Tuesday night. Nocturnal cooling
combined with these winds will likely necessitate a Cold Weather
Advisory after the Extreme Cold Warning has ended through late
Tuesday night. There are indications that temperatures will have a
warming trend late Tuesday night and think that cold weather
headlines will likely end prior to 6 am Wednesday.
Light Snow Chances: Shortwave troughing continues to look
disjointed during the Wednesday through Thursday timeframe, which
makes it difficult to hone in on the details. In this model cycle,
models are showing sufficient saturation for a chance of light snow
as early as Wednesday morning with chances of light snow continuing
at times through Thursday night. A lack of moisture and unfocused
energy will keep potential accumulations very light.
Another chance of light snow will occur from Friday night through
the weekend when more shortwave energy moves through. Again,
forcing looks unfocused so predictability is low with the details
despite potential accumulations looking very light once again.
&&
.AVIATION...for 00Z TAF Issuance
Issued at 515 PM CST Sun Jan 19 2025
VFR conditions are expected through the TAF period, with only
scattered low and mid-level clouds at times. Northwest winds will
subside a little bit tonight, then increase slightly during the
daytime on Monday.
&&
.GRB WATCHES/WARNINGS/ADVISORIES...
Cold Weather Advisory until midnight CST tonight for WIZ005-
010>012-018-019.
Extreme Cold Warning from midnight tonight to noon CST Tuesday
for WIZ005-010>012-018-019.
Cold Weather Advisory until midnight CST Monday night for WIZ013-
020>022-030-031-035>040-045-048>050-073-074.
Extreme Cold Warning from midnight Monday night to noon CST
Tuesday for WIZ013-020>022-030-031-035>040-045-048>050-073-074.
&&
$$
DISCUSSION.....MPC/MPC
AVIATION.......Kieckbusch
Area Forecast Discussion
National Weather Service Gray ME
700 PM EST Sun Jan 19 2025
.SYNOPSIS...
A coastal low will track northeast across the Gulf of Maine
this evening and tonight. Snow will spread into the area to the
northwest of the track later this afternoon and become heavy at
times tonight. Then Arctic air pours into the region and
lingers through midweek before temperatures recover toward late
week.
&&
.NEAR TERM /UNTIL 7 AM MONDAY MORNING/...
7 PM Update...Recent runs of the HRRR and surface observations
indicate the going forecast is in good shape with only minor
tweaks to PoPs with this update. Surface low is currently
analyzed south of Long Island, NY and will track ENE through
tonight. Bands of moderate snow have formed well NW of the low
with one stretching across southern NH into interior SW Maine.
Visibilities under this band are around 1 mile with the primary
hazard through tonight is deteriorating travel conditions due to
snow cover roads and reduced visibility.
Previously...
Second low pressure system in 24 4hours approaching CWA late
today, and continuing to provide forecast challenges. Which
seems to happen in these systems that follow another one
closely, as the models dont really get a hang of the second one
until the first one does its thing. Will begin around sunset
through early to mid evening from SE to NW. and continue through
most of the overnight, although the heaviest snow will likely
fall in the between 7-8 PM and 2-3 AM. With snow winding down
after that and it should all be done by sunrise, except maybe in
the far E zones. The model trend has been back downward on the
QPF in generally all of the models, and the snow totals have
been bumped down a bit. Were still in the borderline warning
area, as far as snow totals go, so no changes to the WWA
products, but a low will depend on the ultimate SLR during the
storm, which are forecast to start in the 10-13:1 range, and
then increasing quickly to 16-20:1 by around midnight or so. So,
will be more of a fluff factor later in the storm, but will also
be affected by strong winds aloft which could break down the
dendrites and limit snow ratios. Also, with increasing winds
some blowing will occur and may also continue after the heaviest
snow ends. Colder air will continue filtering in through the
night and lows will be early Monday ranging from zero to +5 in
the mtns, to the mid to upper teens in the S.
&&
.SHORT TERM /7 AM MONDAY MORNING THROUGH MONDAY NIGHT/...
Everywhere outside the mtns should clear out quickly during the
first half of Monday morning, but a cold NW wind will continue
to through the day. This combined with the temps only rising
about 5 degrees, to near +10 in the mtns, and into the low 20s
in the S, will make for a cold day, with daytime wind chills -10
or less in the mtns, and in the positive single digits in the
S.
Monday will be mainly clear, with a continued NW wind and very
cold with lows around -10 F in the N to zero to +5 in the S.
This combined with the wind will make it feel like -20 to -30 in
the mtns and near -10 in the S. May need some Cold Weather
products for Monday night.
&&
.LONG TERM /TUESDAY THROUGH SUNDAY/...
Arctic air will linger through Thursday morning before
temperatures recover to closer to normal going into the weekend.
Mostly dry conditions are expected from Tuesday into the
weekend.
Tuesday morning starts out very cold with winds chills well below
zero in the morning hours, perhaps as low as -10 to -15F south of
the mountains and even colder to the north. It won`t be quite as
breezy as Monday, but it will still feel quite raw through the day
as winds are still expected to gust to 20-25 mph, offering little
recovery. This will keep winds chills limited to the single digits
during the afternoon south of the mountains while wind chills
in the mountains likely remain below zero. Moisture streaming in
from the Great Lakes and a nearby trough axis may produce light
snow showers across the north late in the day. Partly sunny
skies are expected elsewhere.
Winds diminish Tuesday evening and perhaps enough to set up good
radiational cooling in some areas Tuesday night. However,
whether it`s radiational cooling or a light breeze, it will be
very cold with and feel like -5 to -10F across most of the area.
With fresh snow on the ground, those that do radiate could get
even colder.
Similar conditions are expected on Wednesday to those of Tuesday,
but winds will come down a touch more as broad high pressure builds
toward the NE. If enough low-level moisture is left, the mountains
could see a few upslope snow showers with areas downstream receiving
more clouds. Wednesday night will be very cold with subzero
temperatures possible once again but may not be as cold as the
previous night due to some high clouds moving in.
After the cold start on Thursday, temperatures start to recover
through the day as high pressure shifts east with a gradual warming
trend for temps closer to normal into the weekend. The ECMWF is
advertising the potential for light snow with a weak wave on
Thursday, but there is more support within the ensembles to keep
things dry. Mostly dry weather is then likely to continue into the
weekend as there is strong support among the global models and the
majority of their ensemble members in keeping a coastal low far
enough to the south and east where we see little if any
precipitation from it Fri-Sat. The mountains could end up getting
some upslope activity though over the weekend.
&&
.AVIATION /00Z MONDAY THROUGH FRIDAY/...
Short Term...Mainly IFR in SN at all terminals overnight, could
see some brief periods of LIFR. But should get back to VFR
quickly early Monday morning, continuing through Monday night
night. Could see a few wind gusts to around 25 kt from around
midnight through the pre-dawn hours.
Long Term...Mainly VFR Tuesday through Friday with W/NW winds
gusting to around 20 kt during the day Tues-Weds. The exception
is occasional periods of upslope flow could produce MVFR
ceilings at HIE from time to time along with a chance of a snow
shower. There may also be a slightly better chance for light
snow and restrictions toward late week but confidence is low.
&&
.MARINE...
Short Term...Gales drop back to SCA winds late tonight, but
could surge up again briefly Monday evening. Freezing spray
begins to develop late tonight, and should be with us through
Mon night. Could see Some moderate freezing spray around Pen Bay
late Monday into early Tuesday.
Long Term...Westerly flow could be enough for another period of SCA
conditions over the outer waters on Tuesday, but by Wednesday winds
will diminish as broad high pressure expands toward the Northeast
US. The high moves east on Thursday with southwest flow potentially
increasing to SCA levels. By Friday into Saturday, a developing low
is expected to lift to the north/northeast over the western
Atlantic. The most likely outcome with how things look right
now is for the low to remain to the south and east of the
waters, but it still could bring a period of increasing north to
northwest winds from Friday into Saturday.
&&
.GYX WATCHES/WARNINGS/ADVISORIES...
ME...Winter Weather Advisory until 7 AM EST Monday for MEZ007>009-
012>014-033.
Winter Storm Warning until 7 AM EST Monday for MEZ018>028.
NH...Winter Weather Advisory until 7 AM EST Monday for NHZ001>005.
Winter Storm Warning until 7 AM EST Monday for NHZ006>015.
MARINE...Gale Warning until 7 AM EST Monday for ANZ150>152-154.
Small Craft Advisory until noon EST Monday for ANZ153.
&&
$$
NEAR TERM...Cempa/Schroeter
SHORT TERM...Cempa
LONG TERM...Combs
Area Forecast Discussion
National Weather Service San Diego CA
158 PM PST Sun Jan 19 2025
.SYNOPSIS...
Onshore flow will continue to bring cooler weather and partly
cloudy skies west of the mountains during the nights and mornings
into Monday. Moderate to strong Santa Ana Winds will develop late
Monday and continue through Tuesday evening. A second, weaker
Santa Ana event is possible on Thursday. There is a chance of rain
next Saturday and Sunday.
&&
.DISCUSSION...FOR EXTREME SOUTHWESTERN CALIFORNIA INCLUDING ORANGE...
SAN DIEGO...WESTERN RIVERSIDE AND SOUTHWESTERN SAN BERNARDINO
COUNTIES...
Key Points:
- Moderate to strong and potentially damaging Santa Ana winds Monday
night through Tuesday evening.
- There is a 50-60 percent chance of a moderate strength Santa Ana
event on Thursday.
- There is a 20-30 percent chance of measurable precipitation next
Saturday and Sunday.
Tonight, there will be an inversion establishing itself again for
most of the lower elevations within the inland valleys and along the
coast, which will help to allow for the marine layer to move in
during the later evening hours. There will also be some patchy areas
of fog developing, especially for some of the inland valleys which
are sheltered by the winds. There could also be some of the inner
valleys getting down to around or possibly below the freezing mark
towards sunrise, and therefore areas of frost will also be possible.
Latest model guidance still has the initiation of the Santa Ana wind
conditions tomorrow morning being possible as early as 7 AM for the
higher terrain, with winds switching and increasing out of a ENE`ly
direction. The most recent WRF has some of these winds mixing down
to the lower elevations in Orange County just before Noon, otherwise
in general, it will likely be sometime during the early afternoon
hours for most of the lower valleys and coastal areas to begin to
experience winds increasing out of the northeast. Once this happens,
RH values will begin to drop off quickly, with values falling to as
low as 5 percent locally in some areas, and only a slight recovery
overnight into Tuesday morning. Across the mountains, the HRRR is
still pinging some areas within the Mt. Laguna area having 50kt
pennants at the surface at around 2 AM on Tuesday. This translates
to sustained winds of being close to 60 mph for some of the higher
peaks, as well as gusts of up to near 80 mph possible for a few
remote locations by early Tuesday morning.
As winds decouple Monday night, winds will weaken for some of the
inland valleys. that being said, there could still be enough mixing
for there to be continued gusty winds for some areas, especially for
the coastal regions and valleys not protected by surrounding
terrain. For areas where winds will weaken, very dry air in place
and sufficient radiational cooling as a result will give way to a
chilly night for some of the wind-protected valleys, and patch frost
possible due to this. Where the winds are still mixing to the
surface, temperatures will be quite a bit warmer. This will make it
a challenge for overnight lows achieving their forecast minimum for
some locations Monday night. By later in the morning on Tuesday,
winds will eventually mix down to the surface for all locations with
winds retiring to being gusty out of the ENE for the lower
elevations. The one caveat to this is the WRF showing the formation
of a weak coastal eddy near Carlsbad, which may result in a switch-
around of winds out of the west and weak onshore flow for the Del
Mar area and south to the Mexican border towards the afternoon hours
on Tuesday. If this does occur, with will help to usher in some
cooler temperatures, as well as higher RH values, which may help to
at least mitigate the critical fire weather threat for some of the
inland valleys. By later in the evening on Tuesday, winds should
continue to subside as the pressure gradient loosens, with only some
gusty winds to around 30 mph remaining in place over the higher
elevations, with a cease of Santa Ana conditions elsewhere.
Weak onshore flow at the surface is going to return to the coastal
areas on Wednesday, which will help to also bring back higher
humidity values, especially for the coastal areas. As a ridge builds
back in over the western states, high temperatures will be
relatively warmer and bounce back to being closer to the seasonal
average for this time of year.
With another trough deepening over the Rockies, and high pressure
building in behind it over the Great Basin region by Thursday, Santa
Ana winds will again return to SOCAL with increasing northeasterly
winds at the surface. However, this does not appear to be as strong
of an event, with the highest wind gusts expected for some of the
higher elevations in and around the vicinity of Campo and Boulevard
by Thursday afternoon peaking out around 50 mph. The duration of
this will also be limited, as the high quickly weakens, and is
replaced by more troughing upstream. This will help to weaken the
winds going into Friday, with temperatures being only slightly
cooler, although still right around the seasonal average.
Deterministic models are still displaying some discontinuity in
terms of the development of an upper level low and associated
shortwave trough dropping down over the SOCAL area from Saturday
through Sunday, which depending on the track, could provide some
much needed measurable precipitation, along with cooler
temperatures. There still needs to be some of models in
the upcoming days to determine just how much precipitable water the
CWA will receive, but there is growing confidence that some areas
will receive a chance of rain, especially on Saturday.
&&
.AVIATION...
192100Z....Coasts/Valleys...Stratus has generally moved offshore
with some lingering low clouds, bases 2500-3000ft MSL, in northern
Orange County. There is fairly high confidence in low clouds pushing
onshore again this evening, between 00-03z, with similar bases as
this morning around 1000-1800ft MSL. VIS reductions possible,
especially for coastal terrain, Inland Empire, and valleys where
localized areas of near-zero VIS may occur. Low clouds/FG looks to
clear to the coasts by 14-15z with low clouds lingering in some
spots in the Inland Empire beyond this period. Complete clearing is
expected by 18z Monday as strong northeast winds develop by late
morning.
.Mountains/Deserts...Low clouds look to filter in and push up
against coastal slopes tonight beginning around 03z, leading to low
or no VIS through Monday morning. Clouds should clear mountains by
14-16z Monday as strong N to NE flow develops, with gusts up to 35-
40kts by Monday evening. Strong up/down drafts possible near any
mountains with localized areas of blowing dust.
NWS San Diego is aware of limited communications of observations
from KTRM since January 8th. We are working with the FAA to address
this issue.
&&
.MARINE...
Strong Santa Ana winds develop Monday night, with gusts up to 25 to
30 knots possible over the waters late Monday night into Tuesday
morning. A Small Craft Advisory is now in effect and contains more
details.
&&
.FIRE WEATHER...
There will be a moderate to strong Santa Ana event beginning during
the later morning hours tomorrow, and this will continue through
Tuesday evening. Winds will begin to increase over the higher
terrain initially as early as 7 AM on tomorrow morning, and then mix
down to the surface through the early afternoon hours across the
lower terrain and down to the coastal regions. Strongest winds will
be felt for the higher peaks of around 60 mph, with some gusts of
near 80 mph possible for remote locations. RH values will drop off
quickly for the lower elevations once winds switch around out of the
NE-ENE. We could see values for some areas getting down into the 5
to 9 percent range, even along portions of the coastal region. These
winds will continue to strengthen, with gusts as high as 50 mph over
the inland empire and within a few of the coastal regions by later
in the evening. Winds will also strengthen overnight across the
higher terrain, especially by around 2 AM Tuesday morning. Some of
the winds will decouple and weaken for the inland valleys/coastal
areas, but then begin to increase out of the NE again during the
morning hours on Tuesday after they mix down to the surface. Winds
will remain quite strong throughout the day on Tuesday, and then
begin to weaken going by later in the evening with only weak
offshore flow going into Wednesday.
Winds will begin to strengthen again, with critical fire weather
conditions returning on Thursday, although this will not be as
strong of a Santa Ana event, with only around a 50 percent chance of
being a moderate event at this time. RH values will remain quite
low, and mostly in the single digits to teens, although winds are
not expected to be as strong with this event. There is growing
confidence of a chance of wetting rain going into next weekend as an
area of low pressure could bring some measurable precipitation to
the region.
&&
.SKYWARN...
Skywarn activation is not requested. However weather spotters are
encouraged to report significant weather conditions.
&&
.SGX WATCHES/WARNINGS/ADVISORIES...
CA...Red Flag Warning from 8 AM Monday to 10 PM PST Tuesday for
Orange County Inland Areas-Riverside County Mountains-
Including The San Jacinto Ranger District Of The San
Bernardino National Forest-San Bernardino County Mountains-
Including The Mountain Top And Front Country Ranger
Districts Of The San Bernardino National Forest-San
Bernardino and Riverside County Valleys -The Inland Empire-
San Diego County Inland Valleys-San Diego County Mountains-
Including The Palomar And Descanso Ranger Districts of the
Cleveland National Forest-San Gorgonio Pass Near Banning-
Santa Ana Mountains-Including The Trabuco Ranger District
of the Cleveland National Forest.
High Wind Warning from 8 PM Monday to 8 PM PST Tuesday for San
Bernardino County Mountains-San Bernardino and Riverside
County Valleys-The Inland Empire-San Gorgonio Pass Near
Banning-Santa Ana Mountains and Foothills.
High Wind Warning from 4 AM to 8 PM PST Tuesday for Riverside
County Mountains-San Diego County Mountains-San Diego
County Valleys.
PZ...Small Craft Advisory from 10 PM Monday to 10 AM PST Tuesday for
Coastal Waters from San Mateo Point to the Mexican Border
and out to 30 nm-Waters from San Mateo Point to the Mexican
Border Extending 30 to 60 nm out including San Clemente
Island.
&&
$$
PUBLIC...Stewey
AVIATION/MARINE...Zuber