Strong Atmospheric River moisture on the heels of a strong upper level jet moved across northwest Colorado, with moderate to heavy snowfall over the Elkhead and Park Mountains with lighter snowfall amounts elsewhere. Winds were strong with this system as well.
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The episode as NWS GJT wrote it up.
Strong Atmospheric River moisture on the heels of a strong upper level jet moved across northwest Colorado, with moderate to heavy snowfall over the Elkhead and Park Mountains with lighter snowfall amounts elsewhere. Winds were strong with this system as well.
The local office's own words before the first event, as it sent them, from the Iowa Environmental Mesonet's archive of National Weather Service text.
NWS Grand Junction, CO wrote its last area forecast discussion before the first event at Jan 31, 9:41 PM MST, 3 hours 19 minutes earlier. Its key messages:
Area Forecast Discussion
National Weather Service Grand Junction CO
941 PM MST Fri Jan 31 2025
.KEY MESSAGES...
- Mild and dry conditions continue today with temperatures
topping out 5 to 10 degrees above climatology.
- The next storm arrives Saturday and will bring measurable
snowfall to our northern and central mountains through the
weekend. Heaviest accumulations will be on the northern
mountains.
- Temperatures will warm significantly early next week with
temperatures climbing to around 20 degrees above normal before
the next round of moisture and storms return mid week.
- Unsettled weather is expected to continue next week with
another round of Atmospheric River moisture and heavier snow
arriving Wednesday and Thursday.
&&
.SHORT TERM /THROUGH SATURDAY NIGHT/...
Issued at 323 PM MST Fri Jan 31 2025
A mild westerly flow is resulting in temperatures 5 to 10
degrees above normal with some exceptions being the cold pool
valleys where highs are near to below freezing. High clouds are
increasing as moisture from an impressive Atmospheric River
pushes in from the west. This AR moisture is driven by a fairly
strong upper level jet that will mostly remain to our north with
the strongest upper level winds, but we will still see 120 kts
or so brushing our northern zones. IVTs with this AR are
impressive upwards of 300 kg/m/s or more, which equates to the
99th percentile or above when compared to climo. In addition to
the abundant moisture, temperatures will be mild with H7 temps
down to -3C to -5C during the peak period of snowfall/moisture
so this will result in some low SLRs of 10:1 or even 8:1 in
spots. Regardless of this, winds will be strong with gusts at or
exceeding 45 mph in the mountains. Given all the above factors
and the favorable westerly flow, upgraded the Winter Storm
Watch to a Winter Storm Warning for the Park and Elkhead
Mountains with 8 to 16 inches of snow expected Saturday morning
through Sunday afternoon. The peak moisture (IVT), lift and
forcing seem to match up during the Saturday evening through
Sunday morning timeframe. Other ranges like the Flattops and
Gore and Elk Mountains seem to underwhelm with 3 to 5 inches so
decided not to issue any additional winter weather highlights
for the remaining mountain areas. The higher northern valleys in
the Yampa River Basin could be something to watch as
temperatures are currently on the cusp of rain vs snow. If
temperatures end up colder cause of inversions, we could see
more snow than rain but if it mixes out due to stronger winds
aloft, could limit snow accumulation as the valleys get scoured
out, resulting in rain or a mix.
The rest of the area should continue to see mild temperatures as
this westerly flow remains mild this weekend with lower central
and southern valleys reaching around 10 degrees above normal and
limited precipitation. This system truly will favor the northern
mountains with heavy wet snowfall with enough snow in the
remaining northern and central mountains to be a nuisance but
much less in terms of accumulation.
&&
.LONG TERM /SUNDAY THROUGH FRIDAY/...
Issued at 323 PM MST Fri Jan 31 2025
On Sunday morning, snowfall will be ongoing in the eastern
Uintas and northern and central Colorado mountains. The majority
of snowfall from this event is expected to end sometime Sunday
afternoon or evening, but light snowfall in these areas is
possible through Monday morning. By the conclusion of this event
over a foot of snow is possible in the Park Range. Much less
snow is expected in the central mountains and eastern Uintas.
This event is associated with a moisture surge from an
atmospheric river (AR). However, zonal flow allows for much of
the moisture from this AR to be removed from the atmosphere as
it advects across the Sierra Nevadas and Wasatch Range before
reaching our CWA. Additionally, upper-level support is limited
during this event, with much of it coming from the dynamics of a
slightly anticyclonically curved jet steak positioned to our
north. So, despite widespread PWAT anomalies of over 200-250% of
normal for our CWA, this is primarily a northern and central
mountain event, with the most significant snowfall in the Park
Range. Our next chance for precipitation comes midweek while AR
moisture lingers in our area. Confidence is low due to large
differences between models. However, this event seems to be
trending towards something of interest considering the
atmospheric moisture and potential for favorable dynamics.
This weekends event will be a warm system, as west to
southwesterly flow causes strong warm air advection, raising
temperatures to well above normal through Tuesday. High
temperatures are anticipated to be 5-10 degrees above normal for
areas of higher terrain, and 10-20 degrees above normal in most
valleys Sunday through Tuesday. Temperatures should gradually
fall closer to normal starting Wednesday.
&&
.AVIATION /00Z TAFS THROUGH 00Z SUNDAY/...
Issued at 938 PM MST Fri Jan 31 2025
Broken to overcast high level clouds have moved in across the
area, with ceilings beginning to drop from northwest to
southeast. Look for KASE/KEGE/KRIL to see ceilings flirt with
ILS breakpoints by 12z, and drop below breakpoints by 15z. Snow
showers will begin after 12z for KHDN, as well as KVEL. These
showers will spread south through the mountains to affect KEGE
and KASE tomorrow evening. Surface winds will remain generally
light and terrain driven today, although potentially gusty
southwesterly winds will be possible at the lower elevations
tomorrow afternoon. Sheltered valley terminals, including KASE,
KEGE, and KGUC, will have to deal with some LLWS issues through
the next 24 hour period. VFR conditions are expected to
prevail, but close eye will be kept on northern and higher
elevation terminals again potential MVFR to IFR conditions
during snow showers.
&&
.GJT WATCHES/WARNINGS/ADVISORIES...
CO...Winter Storm Warning from 7 AM Saturday to 5 PM MST Sunday for
COZ004.
UT...None.
&&
SHORT TERM...MDA
LONG TERM...GF
AVIATION...TGJTHazardous Weather Outlook...CORRECTED National Weather Service Grand Junction CO 1232 PM MST Fri Jan 31 2025 COZ001>014-017>023-UTZ022>025-027>029-011200- Lower Yampa River Basin-Central Yampa River Basin- Roan and Tavaputs Plateaus-Elkhead and Park Mountains- Upper Yampa River Basin-Grand Valley-Debeque to Silt Corridor- Central Colorado River Basin-Grand and Battlement Mesas- Gore and Elk Mountains/Central Mountain Valleys- Central Gunnison and Uncompahgre River Basin- West Elk and Sawatch Mountains-Flat Tops-Upper Gunnison River Valley- Uncompahgre Plateau and Dallas Divide-Northwest San Juan Mountains- Southwest San Juan Mountains-Paradox Valley/Lower Dolores River- Four Corners/Upper Dolores River-Animas River Basin- San Juan River Basin-Southeast Utah-Eastern Uinta Mountains- Eastern Uinta Basin-Tavaputs Plateau-Arches/Grand Flat- La Sal and Abajo Mountains-Canyonlands/Natural Bridges- 1232 PM MST Fri Jan 31 2025 This Hazardous Weather Outlook is for northwest Colorado, southwest Colorado, west central Colorado, east central Utah, northeast Utah and southeast Utah. .DAY ONE...Today and tonight. No hazardous weather is expected at this time. .DAYS TWO THROUGH SEVEN...Saturday through Thursday. What's left of an Atmospheric River coming from the west will clip the northern mountains this weekend bringing wet, heavy snowfall. Periods of hazardous travel are likely on Saturday and Sunday. .SPOTTER INFORMATION STATEMENT... Spotter activation is not expected at this time.
The national radar mosaic for the moment the first event began.
1 winter storm. Local standard time, as filed.
Generally 8 to 15 inches of snow fell across the area with locally higher amounts up to 20 inches at Tower. Wind gusts were in the 53 to 60 mph range at Storm Peak Lab.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in Colorado in 2025Every state in 2025This day in weather historyWarnings in Colorado, February 2025
NOAA National Centers for Environmental Information, Storm Events Database, compiled from the National Weather Service’s monthly Storm Data. Complete through 2026-06; NCEI adds each month about 75 days after it ends and revises past years a few times a year. Rebuilt 2026-09-24. Each event’s entry at NCEI: 1239379.