Forecast Discussions mentioning any of
"HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 01/13/24
Area Forecast Discussion...UPDATED
National Weather Service Albuquerque NM
447 PM MST Fri Jan 12 2024
...New AVIATION...
.SYNOPSIS...
Issued at 131 PM MST Fri Jan 12 2024
Strong westerly winds will continue to plague the central mountain
chain and adjacent eastern highlands through Saturday ahead of an
arctic cold front, forecast to move into the northeast plains
Saturday morning and then continue south to Roswell Saturday
night. A significant change in temperatures will be notable, with
a high of 10 degrees forecast in Clayton on Saturday while
Roswell reaches up to 62. A disturbance will bring a round of snow
to western and northern NM Sunday, with some decent accumulations
likely in the northern mountains. A second and stronger push of
arctic air is forecast to arrive in eastern NM on Monday, then
slowly push west to the central mountain chain. Brutally cold
temperatures will persist across northeast and east central NM
through Tuesday. Yet another arctic front may arrive in eastern NM
toward the end of next week.
&&
.SHORT TERM...
(This evening through Saturday night)
Issued at 131 PM MST Fri Jan 12 2024
Winds have been slow to increase this afternoon across the lower
elevations, but we`re starting to see some stronger winds mix down
to the surface at locations like Las Vegas and Clines Corners. RAP
mesoanalysis shows that winds are currently around 40 to 45 kts at
700 mb, but these winds are expected to increase later this
afternoon and into the evening, increasing the chance that stronger
winds will make it down to the surface. A shortwave moving through
the Intermountain West will graze far northern NM overnight. Short-
term guidance shows increased precipitation chances over the Tusas
as a result of orographic lift so PoPs were increased accordingly.
Flow is west at 700 mb and northwesterly at 500 mb, which isn`t
optimal for orographic lift there so only expecting an inch or two
at most. While valleys will likely decouple for a few hours tonight,
there will probably be enough disturbance to allow temps to bottom-
out so leaned towards the higher end of guidance in most areas.
Winds increase across the east slopes of the central mountain chain
and adjacent highlands tomorrow afternoon after a short break, but
should decrease with sunset everywhere except the highest peaks.
High Wind Watch currently goes through 8PM tomorrow, but this may
need to be expired early if current guidance is correct.
A trough over the northern plains will send a modified arctic
airmass into New Mexico from the northeast early tomorrow morning.
This will keep high temps 15 to 25 degrees below today`s highs
across the northeast, but westerly winds from 700mb down to the
surface will likely prevent this boundary from progressing too far
west tomorrow. With sunset, it will likely push further south and
west, but still not make it through the central mountain chain.
While winds will not be particularly strong behind this boundary, a
light breeze will be enough to drop wind chills down to as low as
-20F Saturday night in Clayton, where a wind chill advisory was
issued.
&&
.LONG TERM...
(Sunday through Thursday)
Issued at 131 PM MST Fri Jan 12 2024
Snow will ramp up across northwest and north central NM on Sunday
as a shortwave trough approaches rapidly from over the Great
Basin. Advisory level impacts are possible in the northern
mountains and far northwest highlands, but the Tusas Mountains may
tick up into warning criteria (10"+) and we`ve issued a Winter
Storm Watch for that forecast zone. Meanwhile, much of east
central and especially northeast NM will remain in the freeze
locker with a modified arctic airmass holding on. Clayton is
forecast to reach a high of 13 degrees on Sunday, where the depth
of the cold airmass will be greatest. Elsewhere, breezy to locally
windy conditions will prevail Sunday as winds aloft strengthen
with the inbound shortwave trough. A 2nd and colder surge of
arctic air is forecast to move south down the eastern plains on
Monday and Clayton`s high temperature is forecast at 11 degrees,
which may be a tad optimistic. Monday night will be brutally cold
across eastern NM, with low temps in the single digits down to the
negative single digits. The dense cold airmass will ooze west to
the central mountain chain Monday night and it is unclear whether
or not the front will make it through the gaps and into the RGV.
Very cold conditions will persist Tuesday, with much of the east
central and northeast plains remaining below freezing. Expect a
fairly dramatic warmup on Wednesday as the arctic airmass slides
east out of the area and pressure heights rise across the region
with light to moderate westerly flow. Both the latest GFS and
ECMWF show another arctic airmass invading the eastern plains
around Friday of next week, keeping the temperature roller coaster
going.
&&
.AVIATION...
(00Z TAFS)
Issued at 441 PM MST Fri Jan 12 2024
Strong west to northwest winds have developed this afternoon,
especially along and east of the Central Mountain Chain. Gusts
between 40 and 55kts will remain possible along and just east of
the Central Mt Chain through Saturday, though lower elevation
locations should decouple somewhat overnight resulting in less
wind. LLWS will be widespread tonight, and will impact KGUP and
KLVS TAF sites. LLWS is expected to be most impactful along and
just east of the Central Mt Chain, from KRTN to KSRR. A potent
backdoor cold front will nudge into northeast NM by 15Z Sat, and
will continue to sag southward throughout the day. Winds will
switch around to the northeast and low cigs may fill in behind the
front, at least across far northeast NM.
&&
.FIRE WEATHER...
Issued at 131 PM MST Fri Jan 12 2024
Gusty and erratic west winds continue today through tomorrow
afternoon along and just east of the central mountain chain with
breezy conditions prevailing elsewhere. A few snow showers are
possible in the Tusas mountains tonight, but accumulations will be
light. Another winter storm will impact northern NM Saturday night
through Sunday night, bringing moderate snow accumulations to the
high terrain. Temperatures will remain below average the next
several days and drop well-below average Saturday through Monday
across the northeast plains where a modified Arctic airmass will be
in place. This airmass may squeeze through the gaps of the central
mountain chain and bring the colder temps to central NM Monday
night, but confidence is low. Poor mixing is expected to persist
Monday through at least Thursday of next week.
&&
.PRELIMINARY POINT TEMPS/POPS...
Farmington...................... 9 34 20 40 / 0 0 40 50
Dulce........................... 2 34 9 36 / 10 5 60 80
Cuba............................ 9 34 17 38 / 0 0 20 60
Gallup.......................... 6 37 15 41 / 0 0 5 30
El Morro........................ 9 35 15 38 / 0 0 5 30
Grants.......................... 11 40 19 43 / 0 0 0 20
Quemado......................... 14 39 20 43 / 0 0 0 10
Magdalena....................... 23 45 28 49 / 0 0 0 5
Datil........................... 20 40 24 44 / 0 0 0 5
Reserve......................... 12 51 18 50 / 0 0 0 5
Glenwood........................ 25 51 29 51 / 0 0 0 0
Chama........................... 4 29 9 31 / 40 5 50 80
Los Alamos...................... 16 34 20 40 / 0 0 20 40
Pecos........................... 15 35 21 36 / 0 0 5 50
Cerro/Questa.................... 12 33 18 35 / 5 0 10 40
Red River....................... 5 28 10 29 / 5 0 10 50
Angel Fire...................... 1 25 9 30 / 10 5 10 50
Taos............................ 2 31 11 35 / 0 5 10 40
Mora............................ 13 35 16 39 / 0 0 5 40
Espanola........................ 13 40 17 43 / 0 0 10 30
Santa Fe........................ 14 35 21 36 / 0 0 10 50
Santa Fe Airport................ 14 37 19 39 / 0 0 5 40
Albuquerque Foothills........... 22 43 28 45 / 0 0 5 30
Albuquerque Heights............. 22 44 27 47 / 0 0 5 20
Albuquerque Valley.............. 20 48 23 50 / 0 0 0 20
Albuquerque West Mesa........... 21 45 26 48 / 0 0 5 20
Belen........................... 18 50 21 53 / 0 0 0 10
Bernalillo...................... 22 45 25 47 / 0 0 5 30
Bosque Farms.................... 18 47 21 51 / 0 0 0 10
Corrales........................ 21 46 25 47 / 0 0 5 20
Los Lunas....................... 19 48 22 52 / 0 0 0 10
Placitas........................ 23 41 26 43 / 0 0 10 30
Rio Rancho...................... 21 45 26 46 / 0 0 5 20
Socorro......................... 25 55 28 56 / 0 0 0 5
Sandia Park/Cedar Crest......... 20 36 25 39 / 0 0 5 30
Tijeras......................... 20 38 25 41 / 0 0 5 30
Edgewood........................ 18 39 21 41 / 0 0 0 30
Moriarty/Estancia............... 14 41 18 43 / 0 0 0 20
Clines Corners.................. 18 35 20 39 / 0 0 0 30
Mountainair..................... 21 41 25 43 / 0 0 0 10
Gran Quivira.................... 20 43 24 46 / 0 0 0 5
Carrizozo....................... 26 50 30 51 / 0 0 0 0
Ruidoso......................... 25 45 28 46 / 0 0 0 0
Capulin......................... 8 22 2 23 / 0 0 0 10
Raton........................... 10 35 7 29 / 0 0 0 5
Springer........................ 13 36 7 33 / 0 0 0 5
Las Vegas....................... 18 38 16 40 / 0 0 0 20
Clayton......................... 1 10 -4 13 / 0 0 0 10
Roy............................. 17 32 5 28 / 0 0 0 5
Conchas......................... 22 42 8 38 / 0 0 0 5
Santa Rosa...................... 26 46 17 44 / 0 0 0 5
Tucumcari....................... 22 36 8 32 / 0 0 0 0
Clovis.......................... 27 51 13 34 / 0 0 0 0
Portales........................ 27 57 12 35 / 0 0 0 0
Fort Sumner..................... 26 54 18 43 / 0 0 0 0
Roswell......................... 27 62 23 46 / 0 0 0 0
Picacho......................... 29 57 24 57 / 0 0 0 0
Elk............................. 27 57 26 56 / 0 0 0 0
&&
.ABQ WATCHES/WARNINGS/ADVISORIES...
Wind Chill Advisory from 5 PM Saturday to 8 AM MST Sunday for
NMZ230.
Wind Advisory until 8 PM MST Saturday for NMZ210.
Winter Storm Watch from Saturday evening through Sunday evening
for NMZ210.
High Wind Warning until 8 PM MST Saturday for NMZ213>215-221-223-
226>229-233-239.
&&
$$
SHORT TERM...24
LONG TERM....11
AVIATION...34
AREA FORECAST DISCUSSION
National Weather Service Albany NY
951 PM EST Fri Jan 12 2024
.SYNOPSIS...
Another storm will impact the region today into Saturday with
strong and gusty and widespread precipitation. Mainly snow to
start transitioning to rain with snow holding on the highest
terrain the longest. In the wake of the storm, we will quickly
transition to brisk and cold conditions over the weekend with
with lake effect snow impacting the western Adirondacks and
scattered snow showers across the eastern New York and western
New England.
&&
.NEAR TERM /THROUGH SATURDAY/...
* Another high impact, multi-hazard event for the area. It`ll be
another quick moving system impacting the area tonight into
Saturday. No changes to headlines.
* High Wind Warning for 10 pm tonight to 8 am Saturday for the
Bennington, Berkshire, Washington, eastern Rensselaer, and
eastern Columbia Counties.
* Wind Advisory for 10 pm tonight to 8 am Saturday for the
Helderbergs, Greater Capital Region, Mohawk Valley, northern
Catskills, southern Adirondacks, Lake George Saratoga Region.
* Wind Advisory for 7 pm tonight to 6 am Saturday for Litchfield
County, CT and eastern Dutchess County, western Ulster and western
Greene Counties.
* Winter Storm Warning for 10 pm tonight to 1 pm Saturday for
Hamilton and northern Warren Counties. The snow will wet and
heavy.
* Winter Weather Advisory for 10 pm tonight to 1 pm Saturday
northern Herkimer, and northern Fulton Counties in NY and
Bennington and western Windham Counties. The snow will wet
and heavy.
* Flood Watch 10 PM Friday through 4 PM Saturday for Litchfield
County CT.
UPDATE...As of 940 PM EST, have upgraded all of Washington
County, NY to a High Wind Warning.
Latest RAP13 and HRRR suggesting potential for high winds
partially mixing down into Washington County, especially eastern
portions where some added downsloping effects/drying may allow
low level jet to mix/propagate downward. Potential for 60 mph
wind gusts exists, perhaps even slightly stronger, with
strongest gusts expected between roughly 3 and 7 AM.
Elsewhere, despite radar echoes increasing nearby, NYS Mesonet
webcams suggesting no precip reaching the ground just yet, most
likely due to the existing dry layer above H870. We do expect
spotty precipitation to develop over the next 1-2 hours, mainly
for areas along and west of the Hudson River. Initial P-type
will likely be snow for higher terrain areas above 1000 feet,
and a rain/snow mix below for valley areas from the Mohawk
Valley extending to most of the immediate Capital Region and
slightly south/east of Albany (except all rain in the mid
Hudson Valley/southern Litchfield County), and mainly snow
across the upper Hudson Valley region.
A quick coating to an inch could occur across portions of the
upper Hudson Valley at onset, with little or no accumulation in
other valley areas. Higher terrain areas should see snow quickly
accumulate after onset.
Other than expanding the High Wind Warning into Washington
County, NY and increasing wind gust magnitudes in that area,
mainly just adjusted PoPs/Temps/Winds according to latest obs.
UPDATE...As of 705 PM EST, forecast on track with thickening
high/mid level clouds from southwest to northeast. Temps have
dropped into the upper 20s/lower 30s across portions of the
southern Adirondacks/upper Hudson Valley where cloud cover was
briefly thinner after sunset.
There is quite a bit of dry air within the lower levels of the
atmosphere, so will closely watch trends as significant wet bulb
cooling could allow for a burst of snow to occur for slightly
lower elevations than currently indicated, especially across the
Mohawk Valley and upper Hudson Valley.
Otherwise, no significant changes at this time.
[PREVIOUS 411 PM EST]...The center of the storm is located over
Illinois early this afternoon. It will deepen and track
northeastward across the Great Lakes region with some secondary
development over DELMARVA. The occluded front/triple point will
lift across the area early Saturday. Ahead of this increasing
southeasterly winds and precipitation overspreading the region
as the low- level jet ahead of the system`s warm front moves
into the area with strong isentropic lift. We will cool off
initially this evening then temperatures rise overnight into the
mid 30s to near 50 degrees by sunrise. Temperatures are
expected to peak early Saturday morning from the upper 30s to
lower 50s.
Initially looking at mainly snow overspreading the area this evening
with rain up the Hudson Valley into the Capital District. Snow will
mix with rain then changeover the rain as the night wears with snow
holding on the longest across the highest terrain with a brief period
of mixed precipitation expected as the changeover occurs. Snow is
expected to come down heavy with snowfall rates of 1 to 2 inches
an hour and this will lead to moderate to warning level snows
before a changeover to rain occur by late at night. Steady precipitation
will taper off and transition to showers. Colder air will be
ushered back in on southwesterly winds so a transition to snow
showers will occur.
Southeasterly winds will pick up this evening and be at their
strongest from around midnight into the early morning hours
Saturday with gusts up to 60 mph in the warning area and 50 mph
across the advisory the area. Winds will shift to the southwest
with the passage of the occluded boundary early Saturday morning.
The southwesterly winds will be brisk and gusty through the day
Saturday with gusts of 30 to 45 mph. A wind advisory may be needed
if higher gusts are expected.
&&
.SHORT TERM /SATURDAY NIGHT THROUGH SUNDAY NIGHT/...
Blustery and cold with snow showers and lake effect.
Cyclonic flow on the backside of the system as it moves across
Quebec will result in some westerly upslope and lake effect in
our area. Light snow accumulations are expected across the
western Adirondacks and southern Greens. Temperatures will
continue to drop and are expected to bottom out in the upper
teens to upper 20s which are seasonable for this time of year.
A secondary/arctic boundary will sweep across the region Sunday
and open the door to even a colder airmass. Scattered snow showers
will occurred with the threat for snow squalls. In addition, a
lake effect snowband off of Lake Ontario will shift southward
impacting the western Adirondacks mainly north of Old Forge and
Route 28 as head into Sunday night. A Lake Effect Snow Warning
may be needed while a Winter Weather Advisory for lake effect
snow is expected.
Highs Sunday from the lower 20s to mid 30s with lows dropping
into the single digits and teens Sunday night. The brisk and
gusty winds will make it feel like from around 10 degrees below
zero to single digits Sunday night.
&&
.LONG TERM /MONDAY THROUGH FRIDAY/...
Below normal temperatures look to persist through the long term,
along with with a couple chances for widespread accumulating snow,
along with some localized lake effect snow potential in between.
First storm threat is Monday Night-Wednesday, depending on the track
of a developing coastal low near the mid Atlantic coast.
Ensemble/blended guidance suggest best chances for accumulating snow
mainly south/east of Albany, where higher chance to low likely PoPs
are indicated. Second chance is Friday-Saturday, with another
possible system tracking across the mid Atlantic states and then off
the coast. Again, areas south/east of Albany could have the best
chance for accumulating snow.
Outside of these potential widespread snow chances, more localized
lake effect snowbands may occasionally extend into the SW
Adirondacks and Mohawk Valley region Monday, then again late
Wednesday into Friday. Otherwise, below normal temperatures with
highs in the single digits and teens for higher elevations, and 20s
for valley areas. Wind chills may occasionally drop as low as 5
below zero to 15F below zero across higher elevations, and five
below zero to 10F above zero within valley areas.
&&
.AVIATION /03Z SATURDAY THROUGH WEDNESDAY/...
Through 00z/Sun...VFR conditions this evening with thickening
high/mid level clouds. Precipitation should overspread the TAF
sites between roughly 03Z-06Z/Sat from southwest to northeast.
P-type should start mainly as rain, however could be mixed with
snow at KGFL for the first 1-2 hours. As precipitation intensity
increases, expect Vsbys to become occasional MVFR after an hour
or two of precipitation onset, with mainly MVFR Vsbys then
persisting through Saturday morning. There could be a few brief
periods of IFR Vsbys in pockets of heavier rain.
Cigs will slowly fall once precipitation begins, and may
fluctuate between borderline VFR/MVFR, especially at KGFL where
some downsloping/mixing may limit extent of lower Cigs. Cigs
should eventually trend to MVFR between 08Z-12Z/Sat, then
continue until winds shift into the southwest around midday
Saturday, with VFR conditions then expected to develop during
Saturday afternoon.
Winds will vary between northeast and southeast overnight and
increase to 8-14 KT, with some gusts up to 25-30 possible later
tonight, especially at KPSF and KALB. Winds may remain lighter
at KGFL. Winds will shift into the southwest to west around
midday Saturday and may briefly decrease to 5-10 KT, before
increasing to 8-15 KT during the afternoon, with a few gusts up
to 25 KT possible.
Low level wind shear is expected much of tonight through
Saturday morning, as winds around 2000 FT AGL increase from the
southeast to 40-70 KT, while sfc winds generally remain less
than 10-15 KT (especially at KGFL).
Outlook...
Saturday Night: Low Operational Impact. Breezy. NO SIG WX.
Sunday: Moderate Operational Impact. Breezy. Chance of SHSN.
Sunday Night: Low Operational Impact. Breezy. NO SIG WX.
Martin Luther King Jr Day: No Operational Impact. NO SIG WX.
Monday Night: No Operational Impact. NO SIG WX.
Tuesday: Moderate Operational Impact. Chance of SN.
Tuesday Night: Moderate Operational Impact. Chance of SN.
Wednesday: Low Operational Impact. Breezy. Slight Chance of SN.
&&
.HYDROLOGY...
* Flood Watch 10 PM Friday through 4 PM Saturday for Litchfield
County CT .
River flood warning is in effect for the Housatonic River at
Stevenson. River forecasts have the Housatonic at Stevenson
exceeding moderate flood stage early Sunday morning. The
Housatonic at Gaylordsville is forecast to exceed flood stage
early Saturday morning and at Falls Village Saturday afternoon.
The only other river point forecast to exceed flood stage is
the along the Hudson at Poughkeepsie with tidal flooding near
Poughkeepsie and northward to Kingston. Based on this Flood
Watch has not been changed.
For details on specific area rivers and lakes, including observed
and forecast river stages and lake elevations, please visit the
Advanced Hydrologic Prediction Service /AHPS/ graphs on our
website.
&&
.ALY WATCHES/WARNINGS/ADVISORIES...
CT...Wind Advisory until 6 AM EST Saturday for CTZ001-013.
Flood Watch through Saturday afternoon for CTZ001-013.
NY...Wind Advisory until 6 AM EST Saturday for NYZ058-063-066.
High Wind Warning until 8 AM EST Saturday for NYZ043-054-061-
084.
Wind Advisory until 8 AM EST Saturday for NYZ032-033-038>042-
047>053-082-083.
Winter Weather Advisory until 1 PM EST Saturday for NYZ032-082.
Winter Storm Warning until 1 PM EST Saturday for NYZ033-042.
MA...High Wind Warning until 8 AM EST Saturday for MAZ001-025.
VT...High Wind Warning until 8 AM EST Saturday for VTZ013.
Wind Advisory until 8 AM EST Saturday for VTZ014.
Winter Weather Advisory until 1 PM EST Saturday for VTZ013-014.
&&
$$
SYNOPSIS...IAA/Wasula
NEAR TERM...IAA/KL/Wasula
SHORT TERM...IAA/Wasula
LONG TERM...Rathbun
AVIATION...KL/Rathbun
HYDROLOGY...IAA/Wasula
Area Forecast Discussion
National Weather Service Cheyenne WY
609 PM MST Fri Jan 12 2024
.KEY MESSAGES...
- Strong winds across the wind prone corridors and areas along
and west of the Laramie Range in southeast Wyoming today. High
Wind Warnings have been issued.
- Snow squalls along the Interstate 25 and 80 corridor possible
today, primarily this afternoon.
- Mountain snow continues, with high-elevation travel likely to
remain very difficult or impossible for some time. Winter
Storm Warnings remain in effect for the Snowy and Sierra Madre
ranges through Saturday AM. Another heavy snow event taking
shape for Sunday/Monday. A Winter Storm Watch is in effect for
the Snowy and Sierra Madre Ranges.
- Extremely cold temperatures and wind chill values are expected
across much of SE Wyoming and the Nebraska Panhandle this
weekend. Wind Chill Warnings have been issued for portions of
southeast Wyoming and the entire Nebraska Panhandle.
&&
.UPDATE...
Issued at 604 PM MST Fri Jan 12 2024
Forecast remains largely on track this evening as the arctic
front passed through Cheyenne around 22Z this afternoon. Snow
squall concerns remain this evening as the arctic front pushes
across the I-25 corridor. Snow showers continue east of the
Laramie Range with a heavier band currently just north of
Cheyenne, stretching from 10 miles northeast of Laramie to
Kimball County in western Nebraska. Snow showers expected to
remain in the area throughout the evening hours. Additionally,
allowed most of the High Wind Warning to expire as winds dropped
below criteria around 5PM today. Did extend the High Wind
Warning until 07Z for the Arlington zone due to winds remaining
at high wind criteria and the front remaining stalled across
northern Carbon County. Winds will decrease quickly once the
front moves through.
&&
.SHORT TERM /THROUGH SUNDAY NIGHT/...
Issued at 155 PM MST Fri Jan 12 2024
Currently...Arctic boundary being analyzed along a line from
Pine Bluffs...northwest to Muddy Gap to Bondurant across Wyoming
this afternoon. North of the front...temperatures are below
freezing. Casper currently at 9 below zero...Douglas at 0 and
Chadron is reporting 3 below zero. South of the front...Pine
Bluffs is at 28 degrees...Cheyenne 23 and Laramie 21. Front
forecast to move through the Cheyenne area in the next couple
hours with plummeting temperatures and light snow.
Still have a chance for snow squalls this afternoon. Starting
to see the possible beginning of a convective line showing up
on radar. HRRR and RAP simulated radar showing a band of snow
developing north of Cheyenne along Interstate 25 and out by
Arlington on Interstate 80 at 23Z. Evening crew will need to
continue monitoring radar for possible snow squall warnings.
Kept the high wind warnings going for the Interstate 80
Corridor. Already hitting in Arlington with a peak wind of 73
mph at County Road 402. Other WYDOT sites have hit in that
zone...including Arlington and Strouss Hill. Further
east...we`re seeing mid to upper 40 mph gusts over the Summit
and eastern foothills and the Cheyenne ASOS hit 44 mph earlier.
With the snow squalls developing...still think there is a chance
for some mixing down of stronger winds. Will let the current
warnings run their course.
By Saturday morning...700mb temperatures over southern Wyoming
forecast to be down to -23 to -26C...down from -13 to -15C
currently. Further north across Converse and Niobrara
Counties...700mb temperatures of -28 to -32C forecast. Going to
be brutally cold Saturday. Daytime highs will struggle to get
above 0F along and east of I-25...with low single digits above
zero west. Windchill Warnings look to be in good shape for all
locations with no changes planned.
Get a little break in mountain snow Saturday into Sunday as
arctic front pushes south and takes the snow with it. But snow
returns as the boundary begins to wave back north. NAM...GFS
and ECMWF all are hitting the Snowy and Sierra Madre Ranges
pretty hard with moderate to heavy snow. Getting snow totals out
there approaching 3 feet. Decided on a Winter Storm Watch once
again for Sunday morning through Monday afternoon.
&&
.LONG TERM /MONDAY THROUGH FRIDAY/...
Issued at 155 PM MST Fri Jan 12 2024
Monday and Tuesday, much of central and northern CONUS will still be
under the influence of a potent arctic airmass. This will lead to
extremely cold temperatures and wind chills, as well as chances for
light snow. Monday will be the last bitter cold day as one more
strong push of cold air is progged to drop out of the north.
According to NAEFS 700 mb temperature percentile, this final push of
cold air will be anomalously cold, being in the 0.5th percentile for
temperatures. This will lead to Monday high temperatures below zero
for most locations with even colder overnight lows. Confidence in
these temperatures are high, as ensemble members for both the GFS
and ECMWF show very little spread in potential temperatures. Even
NBM probabilities for low temperatures below -10 are greater than
70% for much of the CWA Monday and Tuesday morning. Breezy
conditions are possible east of the Laramie Range on Monday and into
Monday night. This, combined with potential snow on the ground will
lead to dangerously cold wind chills during the day Monday and early
Tuesday morning. Wind chills, especially at night, will range from
-20 to -50 degrees across the area. Current Wind Chill Warnings are
in effect for the entire CWA through Tuesday morning. Tuesday
afternoon comes the return of high temperatures above 10 degrees.
This secondary arctic push will also bring some light snow to the
CWA during the day Monday. Overall, the best snowfall accumulations
will be in the mountains, where temperatures will be a bit warmer
than the surrounding areas. This will allow for better QPF amounts
on top of the orographic enhancement. The best area for snow
accumulation in the plains will be along the Interstate-80 corridor
from Rawlins to Cheyenne. Between 1 and 3 inches of snow will be
possible in this area from the snow on Monday.
Lastly, the wind will once again return in the long term, replacing
the bitter cold. This has the potential to be a long drawn out wind
event, with in-house guidance suggesting high winds in the usual
wind prones for almost two days. From Tuesday afternoon through late
Wednesday night strong MSLP gradients will exist across the Laramie
Range and points westward. 700 mb CAG-CPR height gradients are also
well above what would be needed to see high winds at Arlington,
ranging from 60 to 85 meters! Winds aloft are also sufficiently
strong, maxing out at 65 kts with great subsidence over the wind
prones. If these conditions hold true over the next several days,
the CWA could have a solid high wind event mid-next week.
&&
.AVIATION /00Z TAFS THROUGH 00Z SUNDAY/...
Issued at 450 PM MST Fri Jan 12 2024
Arctic cold front is currently moving across the Interstate 25
corridor and into the Laramie Range. This feature will bring periods
of snow, possibly a snow squall or two, and gusty north to northeast
winds across most of the area through tonight. Conditions should
gradually improve early Saturday, but another upper level
disturbance is forecast to impact the area with more snow Saturday
night.
HAZARDS/WEATHER TRENDS: Low confidence forecast for timing of IFR or
MVFR conditions due to the banded nature of the snow and snow squall
activity. Generally, went with MVFR prevailing CIGS with periods of
IFR VIS in light snow until 08z tonight. Best chance for snow
squalls and LIFR conditions should be around KCYS, KLAR, AND KRWL
through 03z. Snow squall activity should remain west of the western
Nebraska terminals, but will continue to monitor current trends.
&&
.CYS WATCHES/WARNINGS/ADVISORIES...
WY...Wind Chill Warning until 11 AM MST Tuesday for WYZ101>119.
Winter Weather Advisory until 11 PM MST this evening for
WYZ101-107>111-113-115>119.
High Wind Warning until midnight MST tonight for WYZ110.
Winter Storm Warning until 5 AM MST Saturday for WYZ112-114.
Winter Storm Watch from late Saturday night through Monday
afternoon for WYZ112-114.
NE...Wind Chill Warning until 11 AM MST Tuesday for NEZ002-003-
019>021-054-055-095-096.
&&
$$
UPDATE...AM
SHORT TERM...GCC
LONG TERM...SF
AVIATION...TJT
AREA FORECAST DISCUSSION
National Weather Service Jackson KY
915 PM EST Fri Jan 12 2024
.UPDATE...
Issued at 915 PM EST FRI JAN 12 2024
There is a decent coverage of showers moving quickly east
northeast across the area, and in light of obs/trends have raised
the POP to likely category for most of the area for a time late
this evening.
Winds have diminished considerably early this evening, but are
more stout just to our west. As the steeper low level lapse rates
present to our west make their way into eastern Kentucky in cold
air advection, our winds will pick up again due to increased
mixing. Some gusts could still peak above the advisory criterion,
and the NPW remains in place.
&&
.SHORT TERM...(This evening through Saturday night)
Issued at 530 PM EST FRI JAN 12 2024
Key Messages:
- A strong low pressure moving from the OH Valley to the Great Lakes
will lead to strong wind gusts at times through tonight.
- Wind gusts of generally 35 to 50 mph, with locally stronger
gusts are possible early this evening and again from late this
evening into tonight. A Wind Advisory remains in effect until 7
AM EST on Saturday.
- Temperatures fall to below normal levels on Saturday as cold air
moves into the region. A secondary boundary will usher in an
even colder airmass on Saturday night.
- Isolated to scattered snow showers are possible as colder air
arrives tonight, but little or no accumulation is expected.
Late this afternoon, an upper level low was centered over
northeastern IA with an associated trough axis south through the
Ozarks vicinity to TX while a couple of shortwave trough moving
through the trough and rotating around the upper low were moving
through the OH Valley with one moving into eastern KY at this time
and another over western KY. At the sfc, a bit of a baggy sfc low
was centered over eastern IL to central IN and then an occluded
front trailed southeast to northern KY and then south near the I
75 corridor to a triple point in the TN Valley with a cold front
trialing south into the Gulf of Mexico. After earlier gustiness
as the 850 mb jet max passed over the region, wind gusts in the
higher terrain have diminished over the past hour. However, near
and just behind the front, or near and just after the back edge of
the steadier precipitation, wind gusts have picked up over
portions of central Ky into the Bluegrass region including the
northwest portion of the CWA. Instability is very minimal with 100
J/kg of MUCAPE analyzed over the far southeast with that fleeting
as the boundary moves east.
This evening and tonight, the initial shortwave trough will work
northeast of the region this evening with a second shortwave also
working across the Commonwealth this evening ahead of the main
500 mb trough axis that moves into the Lower OH Valley and
Commonwealth late tonight. The axis of the 500 mb trough moves
east of the area by Saturday afternoon with a brief window of 500
mb height rises later Saturday into Saturday evening. Then the
next upper level trough will move into the Great Lakes and Lower
OH Valley to end the period. The sfc low will track into the Great
Lakes this evening and reach near Lake Huron by early on Saturday
and then continue east and northeast into Quebec and the
Northeast Conus to Maritimes to end the period. The associated
occluded front will cross the region this evening while an arctic
front is expected to develop/strengthen upstream of the region on
Saturday. This boundary will move across the Commonwealth late
Saturday and Saturday night.
For this evening, initial wind gusts to near or into the advisory
range are most probable in the northwest portion of the region
until an hour or two past sunset. Otherwise, a general minimum in
momentum transfer should follow for a couple of hours in between
the initial shortwave that will depart to the east and northeast
this evening and before the wraparound moisture and second
shortwave nears later this evening. HREF and other guidance hints
at the momentum transfer picking back up late in the evening into
the overnight hours. Thunder has been removed from the forecast
this evening as instability is minimal and will decrease further
and is also in line with the recent SWODY1 from SPC. Showers will
remain possible behind the front especially as the second
shortwave nears this evening and these could mix higher momentum
to the surface with gusts into the advisory range in some areas
during a period of a relative min in gusts. As colder air arrives
later tonight, with 850 mb temperatures progged to fall below 0C
for most locations by around 1 AM on Saturday and further to
around the -10C level if not colder around dawn on Saturday, some
snow showers or flurries will be possible overnight as saturation
to about -10C or colder is probable per forecast soundings across
the region. Little if any accumulation should occur with these.
A cold day follows on Saturday with temperatures 5 or more degrees
below normal even though the airmass will moderate between the
departed system and the next shortwave and associated arctic
boundary. Another drop in temperatures will occur behind this
boundary and set the stage for an even colder day on Sunday as the
long term period begins. 850 mb temperatures are progged to fall
further than they will tonight to the -10C to about -17C range to
end the period. Moisture will be limited with the arctic
boundary, but steepening lapse rates should result in isolated
snow showers and isolated to scattered flurries are anticipated
late Saturday evening into Saturday night as it passes as once
again saturation to -10C or colder should again occur.
.LONG TERM...(Sunday through Friday)
Issued at 611 PM EST FRI JAN 12 2024
Key Messages:
* Modified arctic air bleeds across eastern Kentucky on Sunday
behind a shallow arctic front.
* Coastal system develops early next week and confidence may finally
be increasing that it will interact with the arctic front to
produce accumulating snowfall across at least portions of eastern
Kentucky late Sunday night through Tuesday evening.
* Frigid temperatures follow for the middle of the week, though the
magnitude of the cold remains uncertain.
* Unusually high confidence for secondary shot of bitterly cold
temperatures by next weekend, though again the exact magnitude is
less certain.
Analysis and Discussion: There is good synoptic agreement among the
models showing a deep 500 mb trough/low over much of Canada and the
Eastern CONUS at the start of the period on Sunday morning. A potent
northern stream vort lobe extends from from Alberta/Saskatchewan to
Alaska`s North Slope while southern stream energy will be over the
Great Basin. At the surface, an arctic boundary is percolating
through the Appalachians. The latest HRRR soundings show the
depth of the arctic airmass to only around 900 mb.
The 500mb trough/low will wobble in place for the first half of
the extended period before elongating toward the Ohio Valley
during the latter portion of the period. The models continue to
struggle with the progression of the shallow arctic air mass
associated with the system -- which is not unusual. The 18z HRRR
is by far the most bullish with the advance of the arctic air,
showing 2m air temperatures struggling to reach much above 10
degrees by midday on Sunday. The remainder of the model suite
largely suggests temperatures in the 20s (though again the low-
res models struggle with these types of air masses). Later shifts
will need to monitor this arctic air mass as we come into the
range of the full hi-res model data suite. Aside from the
temperature uncertainty, the 12z EPS finally came more in line
with the GEPS and GEFS. A vast majority of the members (>80%) show
the southern stream energy/developing coastal low interacting
with the northern stream energy/arctic cold front to produce at
least a light isentropically-forced snowfall across much or all of
eastern Kentucky. While overall QPF amounts should be light, a
deep and saturated dendritic growth zone and well-below freezing
temperatures through the column favor a dry, fluffy snow (snow to
liquid ration > 16:1). Potential amounts and spatial distribution
should become more certain over the next 24 hours. Once the
coastal low departs into the northeast, expect a reinforcing shot
of arctic air. The coldest air will pass over eastern Kentucky
Tuesday night and Wednesday morning. If skies clear, high pressure
will build in sufficiently for decoupling and very cold night
(sub-zero readings not out of the question). Conversely single
digits are probable if clouds linger or substantial snowfall fails
to materialize.
There should be some alleviation from the frigid air by late
Wednesday and Thursday as that arctic high pressure passes along the
Gulf Coast and sends a "milder" southwest return flow into the Ohio
Valley (850 mb temperatures warm back to near -5C). Meanwhile,
the next potent norther stream vort max, and attendant arctic
front, will drop across the Plains on Thursday. Model guidance
suggests a low developing along this boundary across the Deep
South and eventually turning into coastal storm system. Details
remain uncertain in terms of snowfall for eastern Kentucky, but
cold air won`t be in short supply. Behind the arctic front/coastal
storm, the low-level flow will be more northwesterly and may be
favorably aligned for upslope snow showers and possibly some
Great Lakes enhancement. CPC is advertising Saturday (01/20) as
having a high probability (>60%) for much below normal
temperatures. NBM parameters were largely retained in the long-
term period, though significant downward temperature adjustments
may be needed if the snowier scenarios materialize. After Saturday
(01/13), portions of eastern Kentucky may fail to see
temperatures rise above freezing again for more than a week
(though the warmer locations could eclipse 32F just ahead of
Thursday`s arctic front).
&&
.AVIATION...(For the 00Z TAFS through 00Z Saturday evening)
ISSUED AT 802 PM EST FRI JAN 12 2024
The period started with mostly VFR condition, with the exception
being some MVFR ceilings in the area around K1A6. An area of
showers was progressing eastward into the forecast area from
central KY. Additional MVFR ceilings were present further west in
western and central KY. The regime will shift eastward with time,
with numerous showers making their way across eastern KY this
evening. The lower ceilings will also eventually arrive between
about 02Z and 06Z. Any remaining showers will transition to snow
overnight, but it will not be significant. MVFR ceilings then
persist until around mid day on Saturday and then break up and any
remaining flurries dry up, although the timing on the improvement
on Saturday is tentative.
Winds will also be a consideration. They have slackened somewhat
at the start of the period, but will pick up again from west to
east between about 02Z and 06Z with the development of lower
ceilings. Gusts of 30-35 knots out of the west southwest can then
be expected at times through most of the remainder of the period.
&&
.JKL WATCHES/WARNINGS/ADVISORIES...
Wind Advisory until 7 AM EST Saturday for KYZ044-050>052-058>060-
068-069-079-080-083>088-104-106>120.
&&
$$
UPDATE...HAL
SHORT TERM...JP
LONG TERM...GEERTSON
AVIATION...HAL
Area Forecast Discussion
National Weather Service Pendleton OR
743 PM PST Fri Jan 12 2024
.EVENING UPDATE...Focus over the next 24 hours will be the ongoing
Arctic plunge, as well as another round of snow over primarily the
southern half of our forecast area as a band of elevated NW flow
aloft continues to advect cold, Arctic air over our forecast area.
This NW flow aloft will come with an embedded shortwave that is
expected to bring heavy snow to the Oregon Cascades, Columbia
River Gorge, North Central and Central Oregon, and the mountains
of central and south central Oregon. Temperatures expected to
become frigid overnight as well, with subzero temps likely (70%
confidence) across the CWA tonight, save for the lowest
elevations.
Not much to change this evening with the latest forecast update.
Biggest uncertainty remains just how far north the band of snow
associated with the shortwave will go. Confidence isn`t
particularly high on the current Winter Weather Advisory for the
Oregon Basin and foothills of the Blues (30%), and unfortunately
latest hi-res guidance depicts a very boom/bust forecast for the
advised areas. The line of snow will be very abrupt, so just a few
miles shift in the forecast could mean the difference in several
inches of snow. 00z HREF suggests a more northerly track, but
several members including the HRRR continue to keep the main band
of snow south of the advised areas. Don`t see enough reason to
pull the plug on the advisories given that some hi-res guidance
indicates we`ll verify, but readers should now that this is a
tough forecast with high bust potential for particularly
Hermiston and Pendleton. Messaging for areas under a Winter Storm
Warning, however, remains unchanged.
Overall edits to the forecast package were minor, mainly just
touching up some variables based on latest hi-res guidance.
Evans/74
&&
.PREV DISCUSSION... /issued 415 PM PST Fri Jan 12 2024/
SHORT TERM...Tonight through Sunday night...Bitterly cold Arctic
air has spread across the Columbia Plateau overnight through the
day, and in combination with breezy north-northeast winds,
widespread observed wind chills range from minus 5 to minus 15 for
the foothills of the Blue Mountains, north-central Oregon, Simcoe
Highlands, lower Columbia Basin, and the Yakima, Kittitas, and
Grande Ronde valleys. Exposed ridges in the Columbia Basin and
Yakima and Kittitas valleys are even colder in the minus 15 to
minus 30 range. Have continued the wind chill advisories that were
issued this morning for the aforementioned areas. The coldest
temperatures and wind chills are still anticipated tonight
through Saturday morning, lingering through Sunday morning for
basin areas.
As far as winter weather highlights, it should be noted that a
break in the snow (aside from lingering light flurries) is
forecast this afternoon into tomorrow afternoon for all areas
except central Oregon and the Ochoco-John Day Highlands as the
precipitation associated with the Arctic cold front tapers off and
we await the next system from the Pacific.
Numerical guidance has come into better agreement with the timing
and track of the next system which is beginning to develop
offshore in the eastern Pacific and is evident on satellite as an
open wave. While ensemble guidance is still displaying some
uncertainty in the track of the low as it develops and moves
onshore, better agreement is noted compared to previous runs, and
there has been a slight northward shift in solutions. Heaviest
snowfall is forecast Saturday morning through early Saturday
night, most likely across central Oregon into eastern Oregon with
lower confidence (~40% chance) in snow reaching as far north as
the Tri-Cities in the lower Columbia Basin of Washington. Have
dropped the winter storm warning for the northwest Blues of
Washington as the track of the incoming Pacific low is favored
(>90% chance) to keep snowfall below advisory or warning
criteria. Elsewhere, have continued the existing winter storm
warnings and added warnings for the eastern Columbia River Gorge
as NBM4.2 probabilities of exceeding warning-level snowfall
amounts (3") are supportive (60-80%). Also added winter weather
advisories for the Oregon Basin and northern Blue Mountain
foothills of Oregon where probabilities of exceeding advisory
amounts (2") are mostly 50-80%, except north of Hermiston, Athena,
and Weston where confidence is lower in the band of snow reaching
that far north. The last advisory issued was for the Grande Ronde
Valley.
The low will move out through Sunday morning with precipitation
chances tapering off through the day. Cold temperatures will
persist through the period. Plunkett/86
LONG TERM...Monday through Friday night...The long term will be
characterized by dry and stable conditions to start. The upper
level disturbance that brought the snow across the region will
have moved of to the east and the leading edge of an upper level
ridge will be in place over the Cascades. Northwesterly flow aloft
will persist essentially locking in the cold pool of air left
behind by the arctic front. Temperatures will remain brutally cold
through Wednesday before another upper level low flattens the
ridge bringing westerly flow aloft and another round of
precipitation. The low tracks eastwards along the leading edge of
another upper level ridge with a few shortwaves making their way
across the ridge bringing the potential of multiple swift rounds
of precipitation. Snow levels will remain at Basin floor level
across the region gradually increasing to 2500 ft and above
through the Basin and Gorge and above 4500 ft and above through
central OR.
Monday the models are in good agreement with the track of the
upper level ridge. The only variance in the guidance is the
amplitude of the ridge. Regardless, dry and stable conditions will
prevail through Tuesday night with the main variance being again
the amplitude with a slight variance in positioning and timing.
Northwesterly flow aloft will continue to funnel in cold air
keeping the temperatures through Tuesday very cold. EFI is also
showing that the majority of the region will see well below
average temperatures for this time of year. 45% of the raw
ensembles show temperatures to be between 10-15 degrees only 2%
showing any chances of temperatures higher than that. Tuesday is
showing 26% agreeing on 15-20 degrees. However, the variance in
the ensembles is significant with the majority of the remaining
members show temperatures could be higher.
Wednesday the models are in decent agreement with the upper level
low sliding into the region and flattening out the ridge. Main
variance is primarily with the timing of the incoming
precipitation with only a slight variance in the positioning of
the low. Ahead of the upper level low is a brief warm front that
will assist with raising the temperatures across the region,
albeit by only 5 degrees or so with 63% of the raw ensembles
showing temperatures above 25 degrees and and central OR has
greater than 51% of the ensembles showing the area will see 35-40
degrees. EFI is continuing to show that even these temperatures
are well below the seasonal normal for this time of year. This
warm front will also assist with raising the snow levels although
the Basin, adjacent valleys and the foothills of the Blues will
still see snow levels between 1000-2000 ft. With that said, the
precipitation expected to accompany this upper level low will
indeed bring chances of lower elevations snow due to the cold air
still trapped along the area while central OR will likely see
rain. The highest likelihood for 2 inches of additional snow can
be seen along the Cascades with 65-70% probability, the Blues will
see 60-75% probability for 2 inches and the lower elevations have
20- 30% probability of 2 inches.
Thursday and Friday the models show another ridge will move in over
the region with a band of moisture making its way along it. With
the axis of the ridge settled right over the region, southwest
flow along the WA Cascades will being a band of moisture across
the Snoqualmie area and the northwest flow on the eastern portion
of the region will bring upsloping precipitation to the Blues.
Again the snow accumulations will be relatively light with the
Cascades seeing 50-60% probabilities of another 2 inches of snow,
50-65% in the Blues and less than 20% elsewhere. Raw ensembles are
showing almost a 50/50 split with the temperatures on Thursday so
NBM temperatures are in the forecast with the Basin, adjacent
valleys and the foothills being in the upper 20a to low 40s,
central OR ans along the eastern portion of the region could see
temperatures in the upper 30s to low 40s. EFI is finally showing
the region to be at or just above normal temperatures across the
entire region. Bennese/90
Aviation...00Z TAFs...KYKM/KPSC are the only TAF sites that are
VFR currently and will remain as such through the period.
KPDT/KRDM/KDLS/KBDN are all MVFR due to VIS being below 5SM or
CIGs below 3000 ft. The KPDT/KDLS will see a lift to as the
evening progresses due to the system tracking just south of the
sites. KRDM/KBDN will see a decrease in VIS/CIGs as the system
meanders south. Snow will be the root cause for much of the low
CIGs.VIS through the period. Winds will be between 8-15kts.
Bennese/90
&&
.PRELIMINARY POINT TEMPS/POPS...
PDT -5 7 1 11 / 0 30 70 10
ALW -3 9 5 14 / 0 10 50 10
PSC 4 15 10 18 / 0 10 50 10
YKM -1 11 4 17 / 0 20 40 0
HRI 3 13 7 17 / 0 30 70 10
ELN -6 7 1 16 / 0 10 20 0
RDM 2 7 -5 20 / 40 100 80 10
LGD -8 15 6 22 / 0 30 80 10
GCD 4 26 9 32 / 20 90 90 20
DLS 7 11 6 17 / 10 80 80 10
&&
.PDT WATCHES/WARNINGS/ADVISORIES...
OR...Winter Storm Warning from 10 AM Saturday to 4 AM PST Sunday for
ORZ041.
Wind Chill Advisory until 4 AM PST Sunday for ORZ044-507-508-510.
Winter Weather Advisory from 10 AM Saturday to 4 AM PST Sunday
for ORZ044-507.
Wind Chill Advisory until 10 AM PST Saturday for ORZ049-050.
Winter Weather Advisory from 1 PM Saturday to 4 AM PST Sunday
for ORZ049.
Winter Storm Warning until 4 AM PST Sunday for ORZ502-503-505-
506-508>511.
Wind Chill Advisory until 4 AM PST Sunday for ORZ511.
WA...Winter Storm Warning from 10 AM Saturday to 4 AM PST Sunday for
WAZ024.
Wind Chill Advisory until 4 AM PST Sunday for WAZ026>029-521.
&&
$$
SHORT TERM...74
LONG TERM....90
AVIATION...90
Area Forecast Discussion
National Weather Service Portland OR
400 PM PST Fri Jan 12 2024
.SYNOPSIS...An arctic airmass will continue infiltrating into
southwest WA and northwest OR Friday evening into Saturday, resulting
in widespread below freezing temperatures and dangerously cold wind
chills. This will set the stage for an upcoming winter storm set to
arrive Friday night into Saturday as a low pressure system moves over
the coastal waters towards the central OR coast. Precipitation looks
to fall mainly in the form of freezing rain for the southern
Willamette Valley/Eugene area, central OR Coast Range, and Oregon
coast. Mainly snow is expected for the Portland/Vancouver metro,
southwest WA, the Columbia River Gorge, high Cascades, and Upper Hood
River Valley. A messy mix of sleet, snow, and freezing rain is
expected for the central Willamette Valley/Salem area. Additionally,
very strong east winds will pick up in the
Columbia River Gorge Friday night, lasting through Sunday, and
stretching into the Portland metro area. This will result in blizzard
conditions in the Gorge and far eastern portions of the Portland
metro. Precipitation ends early Sunday morning, though frigid
temperatures will continue into early next week, resulting in
lingering impacts.
&&
.SHORT TERM...FRIDAY AFTERNOON THROUGH SATURDAY NIGHT...The short
term forecast remains highlighted by upcoming frigid temperatures,
strong east winds over and near the Columbia River Gorge, and a
winter storm set to impact most of southwest Washington and northwest
Oregon Friday night through Saturday evening/night. As of 3 PM PST
Friday, an arctic airmass was already beginning to advect into
southwest WA and the greater Portland/Vancouver metro from both the
north and from the east. In fact, surface temperatures had already
fallen into the upper teens to upper 20s across Pacific, Wahkiakum,
Cowlitz, Skamania, Columbia, and northeast Clatsop counties.
Temperatures were right around or just below freezing across the
Portland/Vancouver metro. Temperatures were in the teens and 20s
through the Columbia River Gorge. Meanwhile, temperatures were still
in the low to mid 40s from Salem to Eugene, and along Oregon coast
(except in the Astoria area where temps were right around freezing).
The NBM is handling current temperatures rather well, suggesting
temperatures will continue to plummet through the remainder of Friday
afternoon/evening into Friday night as east winds quickly ramp up in
the Gorge. By sunrise on Saturday, temperatures will likely be in the
teens and 20s over southwest WA and most of northwest OR, except low
to mid 30s along the central Oregon coast from Lincoln City to
Florence. Given the fact that temperatures will then remain frigid
through early next week, this will set the stage for accumulating
snow, sleet, and freezing rain across the vast majority of the area
Friday night through Saturday evening/night as a surface low races
towards the central OR coast. (precipitation type will be highly
dependent on location).
Yesterday, model guidance was still a bit all over the place
regarding the exact track of the low. This resulted in high
uncertainty regarding exact snow and ice amounts. However, model
guidance has come into better agreement today regarding the track of
the low, which in turn has increased our confidence for snow and ice
amounts. Where will the low responsible for the upcoming storm track?
Well, the latest iteration of the GFS/EURO/NAM/SREF are all showing
the center of the surface low tracking somewhere between Florence and
Coos Bay Saturday evening. The Canadian is slightly further north,
which would result in higher snow amounts for southwest WA (think the
Kelso/Longview area and Cowlitz Valley) when compared to the
Portland/Vancouver metro. However, the RAP tracks the low further to
the south, bringing more snow from Salem to Portland and very little
snow for southwest WA. While there are clearly still some model
differences, our current snow/ice forecast is representative of the
most likely outcome, which would be a low track somewhere between
Florence and Coos Bay. As such, still expecting around 2 to 4 inches
of snow across the greater Portland/Vancouver metro by 10 PM
Saturday, 1 to 3 inches for Cowlitz County, much of the lower
Columbia, and the central Willamette Valley/Salem area. However, snow
amounts could wind up a bit less than forecast in the Salem area if
sleet and/or freezing rain winds up being the main precipitation type
rather than snow. Forecast NAM soundings suggest mainly snow and
sleet for Salem rather than freezing rain, but brief periods of
freezing rain are possible. However, if the RAP verifies and the
track of the low winds up a bit further to the south, then the Salem
area could see more snow and less sleet/freezing rain. Expecting
anywhere from 4 to 7 inches in the Columbia River Gorge and Upper
Hood River Valley, and another 10-20 inches of snow for the Cascades
passes. Will need to closely monitor exactly where the deformation
band on the north side of the low sets up a band of heavier snow
Saturday morning/afternoon. From there, will also need to closely
monitor the potential for the band of heavier snow to stall out over
an area. If this happens, a fairly narrow swath of snow amounts in
excess of 6 inches would likely occur somewhere between Kelso and
Salem. However, the probability of this occurring at any given
location is very low (<5%). Current thinking is the band of heavier
snow on the north side of the low will NOT stall out and should be
transient enough to prevent huge snow amounts given the rather strong
westerly flow aloft that should help push the surface low to the
east-southeast after moving inland. Regardless of exact snow amounts,
there is still more than enough snow/sleet/freezing rain in the
forecast to result in significant travel impacts due to slippery
roads and reduced visibilities. Power outages and tree damage are
also likely to occur due to the snow/ice load and windy conditions.
Full fledged blizzard conditions are expected in the Columbia River
Gorge to the west of Hood River as falling snow combines with very
strong east winds gusting between 40-80 mph. Blowing snow and near
blizzard conditions will also pose problems in Troutdale, Washougal,
Camas, Fairview, Wood Village, and northern Gresham where east winds
will be quite strong (gusts 40-50 mph). As such, a Blizzard Warning
has been issued for the Columbia River Gorge and a Winter Storm
Warning has been issued for the Portland/Vancouver metro and the
Oregon Cascades/foothills. Winter Weather Advisories have been issued
for the Upper Hood River Valley, all of southwest WA away from
Vancouver, the north OR Coast Range, and along the coast from North
Cove, WA to Florence, OR (however keep in mind the Florence area is
only expected to see cold rain with little to no impacts).
While precipitation will be mainly in the form of snow for southwest
WA and the Portland/Vancouver metro and mainly snow/sleet for the
central Willamette Valley/Salem area, precipitation will fall mainly
in the form of freezing rain for the southern Willamette
Valley/Eugene area, central OR Coast Range, and most of the
central/northern OR coast from Newport to Manzanita. South of Newport
or Yachats, it appears temperatures will stay slightly above
freezing, meaning nothing but a cold rain from this storm system. The
same outcome is also possible in the Lane County Cascade foothills,
including Oakridge, however uncertainty is higher there. When it
comes to ice accumulations, the NBM is showing a 20-50% chance of at
least 0.25 inches of ice in the central and southern Willamette
Valley, with the highest probabilities over and near Corvallis,
Junction City, Alsea, Albany, Sweet Home and Lebanon. Probabilities
are lowest in Salem, which makes sense as the predominant
precipitation type there should be sleet and/or snow. Probabilities
drop off very quickly to the south of Eugene, which also makes sense
as this is where temperatures will likely be above freezing.
Probabilities for ice accumulations over 0.25 inches are also running
fairly high along the OR coast from Manzanita to Newport at 30-50%.
Ice accumulations over 0.5 inches appear unlikely as probabilities
for that are generally under 10%. Ice Storm Warnings have been issued
for the southern Willamette Valley and central OR Coast Range where
forecast ice accumulations are highest.
The bottom line is to stay up-to-date with the latest forecast to
monitor for potential changes as the exact track of the surface low
becomes even more clear. Now is the time to make prepare for this
winter storm. Anyone with travel plans on Saturday should either
reconsider their plans, or make sure to look up current road and
weather conditions before hitting the road. Lastly, dangerously cold
wind chills of -15 to +15F will significantly increase the risk of
frostbite and hypothermia for anyone outdoors who isn`t properly
dressed for the cold. While the storm is expected to end Saturday
night, conditions will remain frigid and windy. Any snow and/or ice
on the ground will not melt anytime soon, likely not until Tuesday or
Wednesday depending on location (discussed below in the long term
discussion). This will result in prolonged travel impacts that extend
beyond the end of the upcoming winter storm. -TK
.LONG TERM...SUNDAY THROUGH FRIDAY...The forecast beyond this
weekend`s winter weather is largely unchanged as frigid temperatures
are expected to linger through the early part of next week behind the
departing system. Ensemble clusters continue to show strong
agreement on a ridge building over the Pacific Northwest Sunday
through Tuesday, with overnight lows bottoming out in the teens in
the interior lowlands and in the 20s at the coast each morning
through Tuesday. Latest guidance also continues to indicate daytime
highs remaining below freezing in the Willamette Valley until Tuesday
afternoon if not Wednesday. Forecast pressure gradients suggest
gusty east winds will continue through the Columbia River Gorge
through the period, potentially leading to dangerous wind chill
values in the single digits or even below zero at in and around the
Gorge at times through Tuesday morning.
The bulk of the medium range guidance depicts a quick moving
shortwave trough over southern British Columbia temporarily
flattening the ridge later Tuesday into Wednesday, bringing the next
chance for precipitation to the area towards the middle of next week.
Generally speaking, expect this to be a warmer system with snow
levels climbing to around 4000 across the Cascades on Wednesday. The
primary forecast concerns will revolve around how quickly the cold
air will be scoured out of the interior valleys, particularly through
the Gorge into the northern parts of the Willamette Valley where
persistent easterly winds will continue to supply colder air from the
Columbia River Basin. Will have to monitor the potential for
freezing rain in these locations as a result, but the details are
still very much up in the air at this time. Guidance hints at drier
conditions returning by Thursday before another system arrives
towards the end of next week. /CB
&&
.AVIATION...Radar imagery and terminal observations as of 00z Sat
show mostly dry conditions across northwest Oregon and southwest
Washington as the area enters a lull before a winter storm impacts
the region Saturday morning. Some locations are seeing drizzle
and/or non-impactful snow flurries. Cigs are currently MVFR with
localized IFR cigs. Expect predominately MVFR cigs to continue
tonight through tomorrow as east winds pick up and dry out the
lowest levels. Freezing rain is forecast to begin tonight in the
south Willamette Valley after around 05-06z Sat, with freezing
rain/sleet/snow beginning in the central Willamette Valley/KONP
after 12-15z Sat, and snow in the north Willamette Valley/KAST
after 15-18z Sat.
Before this winter precipitation arrives, east winds will
strengthen, especially for northern Willamette Valley terminals
and KAST. The forecast pressure gradient between KTTD and KDLS is
very tight which correlates with a strong easterly wind. At the
surface, the areas that will experience the wind will generally be
KAST, KPDX, KTTD, KHIO, K4S2 and the mountains. Areas south in
the central Willamette Valley will also be windy. Winds will
really begin to enhance after 03-06z Sat. Winds in the Portland
Metro Area could gust up to 45-50 kt, especially near the mouth of
the Columbia River Gorge. Meanwhile, winds in the central and
south Willamette Valley are expected to be northeasterly and gust
up to 20-25 kt. While there may not be as much directional shear,
the speed shear may be present up to 1000 ft.
PDX AND APPROACHES...Predominately MVFR cigs with accumulating
snow beginning 16-18z Sat and lasting through the entire TAF
period. Expect sub-freezing temperatures with easterly winds.
East winds begin to pick up around 03-06z Sat, with gusts up to
30-35 kt by 12z Sat and 40-45 kt by 18z Sat. Gusts up to 50 kt
are possible near the mouth of the Columbia River Gorge Saturday
morning. -Alviz/Muessle
&&
.MARINE...Considering the active nature of the next several days,
there will be minimal impact on the marine environment. Small
Craft Advisories remain in effect across all of the waters through
late Saturday evening. Saturday morning, a low pressure system in
the NE Pacific will approach the waters. Models are suggesting
that this ~1000 mb low will move inland by late Saturday night
somewhere between Cape Foulweather and Cape Arago. The approach of
this low pressure system will tighten pressure gradients and
increase easterly winds Saturday. Areas near E-W aligned gaps in
the terrain in the inner waters may experience periods of low-end
Gale force gusts. Due to the localized, short term nature of these
Gales, have decided against issuing a Gale Warning. More widespread
Gales are forecast for the waters south of Florence, OR.
This approaching system will be very cold and include a wintery
mix of snow, rain, sleet, and even freezing rain on surfaces. Due
to freezing temperatures in the forecast in conjunction with
strong east winds, a Freezing Spray Advisory has been issued for
the Columbia River Bar beginning Friday night through Saturday
night. In addition, a very strong ebb that`s forecast for 558 PM
Sat will allow for more fresh water (which freezes quicker than
salt water) to be exposed to the surface of the Bar. Mariners in
the Columbia River Bar should prepare for potential ice accumulation
on their vessel, especially for waters in the eastern half of the
Bar where water temperatures are colder. -Alviz/Muessle
&&
.PQR WATCHES/WARNINGS/ADVISORIES...
OR...Winter Weather Advisory from 10 PM this evening to 10 PM PST
Saturday for Central Oregon Coast-North Oregon Coast.
Winter Weather Advisory from 7 AM to 10 PM PST Saturday for
Coast Range of Northwest Oregon-Lower Columbia.
Ice Storm Warning from 10 PM this evening to 10 PM PST Saturday
for Central Coast Range of Western Oregon-South Willamette
Valley.
Winter Storm Warning from 7 AM to 10 PM PST Saturday for
Greater Portland Metro Area.
Winter Storm Warning from 10 PM this evening to 10 PM PST
Saturday for Central Willamette Valley.
Winter Storm Warning until 4 AM PST Sunday for Cascade
Foothills in Lane County-Cascades in Lane County-Northern
Oregon Cascade Foothills-Northern Oregon Cascades.
Winter Weather Advisory until 4 AM PST Sunday for Upper Hood
River Valley.
Blizzard Warning from 7 AM Saturday to midnight PST Saturday
night for Central Columbia River Gorge-Western Columbia
River Gorge.
WA...Winter Weather Advisory from 7 AM to 10 PM PST Saturday for I-5
Corridor in Cowlitz County-South Washington Cascade
Foothills-South Washington Cascades-South Washington Coast-
Willapa Hills.
Winter Storm Warning from 7 AM to 10 PM PST Saturday for
Greater Vancouver Area.
Blizzard Warning from 7 AM Saturday to midnight PST Saturday
night for Central Columbia River Gorge-Western Columbia
River Gorge.
PZ...Small Craft Advisory until 10 PM PST Saturday for Coastal
waters from Cape Shoalwater WA to Florence OR out 10
NM-Columbia River Bar-Coastal waters from Cape Shoalwater WA to
Florence OR from 10 to 60 NM.
Freezing Spray Advisory from 10 PM this evening to 10 PM PST
Saturday for Columbia River Bar.
&&
$$
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