Warm West - Cold East

It's been feeling more like March than early February across Utah the past 4-5 days. Highs in the 50s along the Wasatch Front and sunny skies. Even the birds are chirping more and a few flower bulbs are starting to creep out of the ground. Today temps will once again climb into the low 50s F for most Wasatch Front valley locations, with  highs in the upper 30s and low 40s for much of the mountain areas. The satellite loop below outlines the dome of high pressure across the western U.S. and the accompanying storm track across Canada down into the upper Great Plains. 

GOES-18 West True Color with Water Vapor imagery overlay 2/4/2026. The rex block pattern is noted (high over low)

A strong upper-level ridge and blocking pattern (rex block) has set-up shop across the western U.S. 500 mb heights (5820 m) associated with this ridge look to have broken the record maximum observed 500 mb (5785 m) at KSLC for today (2/4). Heights > 5800 m are more common in the late spring and summer than in February, so very abnormal for this time of year. For background, heights of a pressure surface increase as the mean temperature of the air in the column below it increases - based on the hypsometric equation for the atmosphere. This pattern has been keeping conditions dry and abnormally warm for the West, but has been conducive for surges of artic air and winter storm tracks to dive south and east over the middle and eastern areas of the U.S. I have been calling this pattern a "Dipole pattern" but is also known as the "Warm West and Cold East pattern". 

Analyzed 500 mb heights and temperatures (C) 12Z 2/4/2026. Upper-level and temperature pattern overlays  

PRISM Daily mean temperature (F) anomaly for 2/1-2/3/2026. Warm West and Cold East

When Will Utah See Weather Again?

Utah weather event timeline 2/4-2/19/2026

There's lots of hype online about a pattern switch arriving next workweek and what that means weatherwise across the western U.S. Ensembles have continued to trend for a pattern shift come sometime 2/9-2/13/2026, but detailing out precipitation amounts and timing are still a fool's errand.  The ensemble 500 mb heights for 2/10/2026 and the 5-day 500 height anomaly for the period 2/11-2/16/25026 below identify a troughing pattern setting up across the West. 

While there is growing confidence that the stubborn ridge and blocking pattern will weaken/dissipate 2/9-2/13/2026, confidence is low in terms of how weather specifics will play out. The available analysis generally reveals that a cooler and more active period can be expected going into mid February for Utah. That's not saying awfully much, considering any conditions other than the present would be cooler or more active, but it is nice to know there may be an end to the stale weather. The ensemble ECWMF precipitation plume below notes the potential for a few waves of moisture mid month. I would not focus on exact precip numbers at this point, but note the general timing and magnitude of each wave.

12Z ECMWF ENS 2/4/2026 Total QPF plume for KSLC

We can gain another perspective on forecasting this pattern change by looking at the Pacific North American (PNA) signal. In the image below, the ECMWF ENS PNA index is given and reveals the PNA going negative around 2/9-2/10/2026 and staying negative through the third week of February. A negative PNA index indicates a troughing pattern setting up over the U.S. Pacific coast and a corresponding active/stormy pattern.  

12Z ECMWF ENS PNA Index 2/4-2/19/2026

Still a lot to be figured out for next week's forecast, but there is a buzz of hope that precip in the frozen form is in store for the Utah mountains in the near-ish future. As horrible of a winter the West has had, we will need a very wet end of February and March to get back to a manageable position snowpack-wise. A snow drought could potentially create a cascade of impacts, including creating a bad dust and fire season across the western U.S., not to mention the significant strain it would put on agricultural and residential water resources. February and March are traditionally wetter months for Utah, so let's hope that stays true this year... 

I'll leave this here...

SNOTEL Percent Median SWE as of 2/4/2026

Foggy

Freezing fog and fog flurries SLC 1/29/2026

A bit icy across northern portions of the Salt Lake Valley this morning, as low-level moisture from yesterdays storm and a trailing stable airmass have created areas of freezing fog and fog flurries. Most fog and associated flurry activity is focused across valley locations near the GSL. Roads conditions are a bit icy with a dusting of snow/ice, so nothing too significant. Fog will likely dissipate or retreat over the GSL as the day progresses. May get additional valley fog development near the GSL again Thursday night into Friday morning. 

The mechanisms responsible for the freezing fog and the attendant fog flurries are somewhat interesting - at least to me -, and don't occur all that often. Typically, snow flakes like to form in a saturated layer of the atmosphere where the temperature is less than -10 C and even more so when the temp is between -12 to -17 C - blue highlighted portion of the red temperature trace in the sounding below. This layer is called the dendritic growth zone and is needed for efficient snowflake formation. However, this morning the sounding from KSLC reveals the saturated layer did not quite have temperatures within the dendritic growth zone. So how did we get flurries to form in the fog? 

KSLC 12Z 1/29/2026 sounding with overlays

I'm not an expert in cloud microphysics, but I will attempt to provide an explanation for the flurry development in the fog.  A mix of different types of ice crystal formation in the lower level of the atmosphere were most likely responsible for the fog flurry formation. Ice crystals developed via a combination heterogenous nucleation and ice multiplication in the colder, super-cooled (< -10 C) saturated layer (highlighted in blue). These ice crystals that formed it the colder layer aloft precipitated down into the underlying 'warmer' layer (-2 to -10 C) saturated layer (highlighted in green), where the falling crystals collided with supercooled water droplets/or other ice crystals to produce larger ice crystals and small snowflakes via a combination of riming and aggregation. This was in effect a seeder-feeder type of process (image below). If not for the colder saturated layer aloft that produced falling ice crystals, the fog would have just remained freezing fog rather than also precipitating snow.

Seeder feeder mechanism

Going Forward

The punchy shortwave trough that moved across northern Utah yesterday was an interesting change up but not anything to write home about. A few brief periods of moderate snow showers impacted the Wasatch Front, with some valley locations picking up a dusting+. The higher resorts in the canyons managed to squeeze out 1-3" in accumulations, mainly thanks to enhancement from orographic lift. 

The short-term forecast doesn't look great. Ridging builds back over the western U.S. and Utah going through the end of the workweek and into the weekend. Temperatures will moderate each day and haze will likely develop at times. Highs potentially peak into the 50s by Saturday or Sunday. Models have trended on bringing a weak shortwave trough over the top of the ridge early next week. The trough looks to graze Utah, but the potential for any precipitation as of now looks very low. The good news is the energy and associated cooler temps may help keep things marginally fresh in the valleys and reduce the strength of any haze/inversion conditions.

ECMWF ENS 12Z 1/29/2026 - Left: 500 mb heights 2/5/2026; Right: 5-day 500 mb height anomalies 2/1-2/5/2026

For the long-term, other than that weak trough early week, conditions look to stabilize again by mid next workweek, with a strong ridge forming over the interior west. This could be one of the stronger ridges this winter, with model ensembles putting a ridge with 500 mb heights > 5800 m over Utah by 2/3-2/5/2026. This ridge combined with a Rex Block set-up (high pressure over low pressure) will likely keep Utah dry going through mid-ish February. If we want to rub the crystal forecasting ball hard, ensembles have the pattern shifting and the next opportunity for active weather coming mid February, but that is very much TBD...

Unprecendented?

The air has finally cleared out along the Wasatch Front thanks to a weak disturbance that moved over the state this weekend. Unfortunately, moisture was lacking and no significant precipitation fell. A few flurries at times in the mountains were observed and even in the valley but that's all she wrote. However, temperatures were knocked down to more seasonal normals (upper 30s) for a few days. Today, morning temps bottomed out in the teens across the northern Utah valleys, but with cloudless skies and a bit of warm air advection highs will climb into the mid 40s for most areas this afternoon.

For those hoping this week offers a change up in the pattern, I am sorry to say Utah will largely be seeing similar conditions as the previous 10-14 days. Other than a weak system that looks to move across the state mid-week, there is nothing else on the radar for another 7-10 days. As I always say, things can change, but ensembles and the model trend have been fairly consistent in developing another ridge across the western U.S. going through the end of January and beginning of February... sad.

The Snowpack State of Affairs

It's been an interesting winter so far, or rather a non-winter. By some numbers, it's the lowest snow year in history to date along the Wasatch Front. By other numbers, the snow is low but not the lowest it's ever been. The story is split by elevation. The snowpack for areas > 9000' isn't spectacular but is also not in dire straits. Currently, the SWE at or above this level is 75-85% of normal, and actually, just 14 days ago, the snowpack in this elevation band had climbed back to average SWE for the date (100% of normal). 

SWE percent of 1991-2020 median

The story is much different for the mid 6000-8500' elevations, where the snowpack is largely nonexistent or historically low (0-50% of normal). There are many areas, particularly south facing, that are completely snowless up to 8500'. Below 6000', the Wasatch Front valleys have experienced their least snowy winter to date, with the SLC airport only observing 0.1" of snow accumulation as of the time of this post. For perspective, the winter with the second and third, lowest snow accumulations to date was last season 2024-2025 with 6.3" and the 1933-1934 season with 11.3", respectively. Ignoring last winter, that's a 11.2" difference between this winter and the 1933-1934 winter. Not only is this winter the lowest on record for SLC, the low snow is unprecedented. 

Year-to-Date Summary	Observed 2025-2026	2024-2025	1933-1934	Normal	Record Highest	Record Lowest
Total Snowfall (since July 1)	0.1	6.3	11.3	30.5	81.3 in 1993	0.1 in 2026

Why is there such a sharp gradient in the snowpack? 

What's to blame for the low tide snowpack..? The main culprit is the significantly above normal temperatures this winter. The average temperature for December 2025 was 43.7 F in SLC, which is over 10 degrees above normal (32.2 F) for the month. January 2026 has cooled off some, but still has been above average (table below). 

	Dec 2025	Dec Normal	Jan 2026	Jan Normal
Avg Max Temperature	51.4	39	43	38.3
Avg Min Temperature	36	25.3	27.9	24
Avg Temperature	43.7	32.2	35.5	31.2

In short, the lack of near freezing temperatures have caused precipitation to fall as liquid rather than frozen. This winter has been dry at times, but not below normal. If you were to look back from the start of the water year (Oct. 1), SLC has actually seen above average precipitation - 6.99" since Oct. 1 compared to the normal 5.14". And if you were to look at total precipitation accumulation at SNOTEL sites focused across northern Utah, most sites are near normal liquid to date. However, the recent dry spell and continuation of dry conditions will definitely edge our winter to the drier side.

Total precipitation percent of 1991-2020 median

Going Forward

Not much is going on weather-wise across Utah and the interior western U.S. in the short or long term. A transient ridge will build over the state early week before a weak system moves over mid workweek. Not much, if any, precipitation is anticipated with this storm. Temps will be knocked down some and the mountains may be able squeeze a skiff out, but that may be it. Unfortunately, the forecast looks bleak, with dry and relatively mild conditions persisting across Utah into early February. 

The upper-level dipole pattern will continue, with ridging in the west and troughing in the east (figure below). While areas east of the continental divide get blasted by artic air bouts of winter weather, the western U.S. will potentially be under the ridge that will never die. Usually, I save the term "death ridge" for a summertime ridges with 500 mb heights > 5900 m, but deterministic models have been hinting at a ridge with 500 mb heights ~ 5800 m setting up over the western U.S. by next week. Heights of that magnitude - in the middle of winter - are incredibly anomalous and would be associated with an abnormally warm airmass. If this model solution verifies, or is even close, I think we would be able to label it a "death ridge" for winter. 

12Z ECMWF ENS 5-day 500 mb height anomaly (m) 1/26-1/31/2026

Ensembles are less aggressive with the strength of the ridge going into February, but still note large positive height anomalies associated with the ridge over the west (above figure). Let's just hope we have a wet end of February and March. I don't think we will be able to make up all the ground lost, but at least we can minimize the deleterious impacts of a significant snow drought... 

For Loop

Clear skies with lows in the 20s F this morning across the Wasatch Front valleys, with some high level clouds and temps maxing out in the 40s F this afternoon. Feels a little familiar... 

We've been stuck in a loop across northern Utah and we need a break. Everyday for the past 5-7 days has had pretty much the same weather and periods of poor air quality. This pattern will continue for the next two days, so a little bit of a broken record but persistence forecasting does work well in this situation. 

KSLC 2m Temperature (F) 1/15-1/21/2026

What's the reason for the weather on repeat and bad air? 

Utah has been stuck on the downstream periphery of a large and stubborn upper-level ridge for the last 10 days or so. It's a frustrating position to be in, with the storm track to our east and high and dry conditions overhead. However, being on the edge of the ridge does give Utah some fringe benefits. Energy diving south on the backside of the ridge can graze the state and keep the mid-levels of the atmosphere fresh enough to weaken our valley inversions. Thankfully, this has been the case, with air quality improving over this past weekend as a few shortwave troughs clipped the state. The glancing blows from the troughs brought the addition of cooler mid-level temperatures and some elevated mid-level winds that helped vent/mix-out the valley at times. 

Hourly PM2.5 concentrations (umg/m3) 1/15-1/21/2026 at Hawthorne and Copperview air monitoring station

Keep an eye on the blue dashed lines (representing 700 mb temps < 0 C) in the animation below from 1/15-1/20/2026 and note how the isotherms change through time over Utah. Pockets of colder temperatures are associated with the shortwave troughs progressing through the flow. From 1/15 to 1/17/2026, 700 mb temps decreased from +4 C to -4 C, respectively. This cooling is also noted in the KSLC soundings shown below from these dates. Even what seems like a subtle changes - a delta of a handful of degrees C - can weaken inversion conditions and "lift the cap/lid", allowing air trapped in the valleys to release. 

700 mb Analysis heights, temperature (C), and winds 1/15-1/20/2026

When will the loop break?

Going through the end of this workweek and into the weekend there is both good and bad news. The good news is that a trough and attendant cold front will dive south out of Canada and progress across Utah 1/23-1/24/2026. There is still some uncertainty on how far the trough will dig into Utah, but the upper-level energy and influx of colder air will help sweep out the valley and inversions for good - at least for a short time - and bring some colder temps. Maybe even bring our temps back near normal. But - and here is the bad news - moisture will be lacking as this system passes over northern Utah and no significant precipitation looks impact the area. Southern Utah does look to squeeze out some rain/snow showers as a southern tracking system merges with the trough out of Canada, but even there the precip amounts look fairly light. 

ECMWF 12Z 1/21/2026 four-panel forecast 1/21-1/25/2026: (Top left to bottom right) MSLP/precip and 1000-500 mb thickness; 300 mb gph and winds; ; 500 mb gph, vorticity, and winds; 700 mb gph, RH, temp, and winds

So... unfortunately, no new snow is in the forecast for northern Utah going through this weekend. Beyond that, the pattern looks to return to something along the lines of what we are experiencing currently, which is dry and somewhat mild. That's not exactly hopeful news, but things can always change. I think Utahn's and people across the western U.S. are searching for a light at the end of the dark tunnel that has been this winter. However, I don't see that light just yet... I will leave you with the image below.

Basin Snow Water Equivalent Percent of 1991-2020 median 1/20/2026

Put up the Snorkel

Very soupy along the Wasatch Front this morning, so put up your snorkels to get a breath of fresh air. The air quality is not great. Particulate concentrations (PM2.5) have been oscillating around 25-35 ug/m3, which corresponds to a yellow to orange AQI level if you're more familiar with that metric. 

Left: view of the Utah Capital building through the inversion haze; Right: PM2.5 concentrations across the Wasatch Front 1/14/2026

Why is this happening?

Utah is still inverted. That's the short answer. The longer explanation has to do with a dome of high pressure and blocking pattern set-up across the western U.S. Currently, ridging in the west and troughing east of the continental divide is creating a dipole pattern across the country, with quiet and warm conditions across the west and active and cold conditions across the east. 

Analyzed 12Z 1/14/2026 500 mb heights and temperature (C), with overlays - ridging/warmer temps (red shading); troughing/colder temps (blue shading)

The dome of high pressure over the west is associated with a large blob of mid-level warm temperatures, which is helping to keep the Utah valleys inverted. The warmer mid-level temperatures overlay the colder air pooled in the valleys and inhibit much or any vertical mixing. Overtime, pollutants build up in the valleys because air is 'trapped' or is unable to vent out. Until cooler air aloft or strong surface to mid-level winds arrive, the inversion conditions and poor air quality continues. High pressure is also directing storm activity well north into Canada, keeping conditions stagnate for locations across the west. 

Left: KSLC 12Z 1/14/2026 sounding;  Right: ECMWF 06Z 1/14/2026 700 mb temperature (C)

When will this end?

Weather event timeline 1/14-1/24/2026 for northern Utah

Unfortunately, there is no clear end time to the inversion within the next 7-days. There is a potential for some improvement and weakening of the inversion across Utah come this Friday-Saturday (1/16-1/17/2026). Currently, models forecast a trough grazing northern Utah late week into the early weekend, bringing cooler mid-level temps and possibly some stronger mid-level winds. Uncertainty still remains to what degree this trough will graze the state and if any of the changes it brings equates to a weakening of the inversion and improvement in air quality. 

ECMWF 12Z 1/14/2026 700 mb temperature (C)

Other than the possibility of some short-term relief going into this weekend, no other active weather is on the horizon until mid to late next workweek (1/22-1/24/2026). This is still very far off, so plenty of uncertainty remains on what sort of activity will occur. But models continue to trend that a break in the pattern will occur sometime around that time frame. The ECMWF Ensemble 5-day 500 mb height anomalies reveal the ridge/blocking pattern dissolving late next week and allowing some potential troughing across the west. For all the Utahn's wanting clear air and more snow, we are at least 7-10 days out from the next opportunity...

ECMWF ENS 00Z 1/14/2026 5-day 500 mb height anomalies - Left: 1/14-1/19/2026; Right: 1/21-1/26/2026

ECMWF ENS 00Z 1/14/2026 Total Precipitation Accumulation (in) at KSLC

Hopefully, as the atmosphere shifts later this month, the colder air and snow will make it's way across Utah. The Utah snowpack is still in poor shape, excluding a few outliers, but that is a conversation for another time. The later half of this winter has a lot of makeup work to complete...

The Other Side

The story is very different east of the continental divide, where multiple Artic blasts and winter storms are possible going through the next week. If we look at forecasted surface pressure (MSLP) over the next week, we can get a good idea of where and to what strength artic air is being generated in western Canada and Alaska. 

ECMWF 12Z 1/14/2026 Forecasted MSLP (mb)

Areas of higher pressure (warm to dark colors) signify pools of very cold artic air. The higher the pressure the colder the Artic air mass (cold air is more dense, hence higher pressure). Through the course of the animation above, we can see a few blobs or areas of high pressure > 1040 mb (dark colors), which is typically a good threshold for distinguishing potential areas of an artic cold air outbreak. These areas of high pressure can be seen diving south into the central and eastern U.S., and correspond to very cold temperatures, indicated by the 850 mb temp animation below.

ECMWF 12Z 1/14/2026 Forecasted 700 mb temperature (C)

All Quiet Along the Western Front

A bright, cold, and hazy morning in the SLV. Temperatures bottomed out in the teens to 20s for the Wasatch Front valleys, with temps in the upper 20s to around 30F for the upper mountain elevations.  Cache Valley caught a bit of fog overnight and early morning, while generally clear skies dominate across the remainder of the state. Colder valley temps, haze, and fog are all symptoms of high pressure and inversion conditions. The sounding from KSLC this morning definitely shows a strong temperature inversion from the surface (26 F) to about 700 mb ~ ridgetop level (34 F). 

GOES-19 East True Color Imagery 1/12/2026

KSLC 12Z 1/12/2026 sounding. Inverted profile sfc-700mb

After the first true powder weekend of the winter, the excitement is starting to stabilize and the realization that we will be stuck in a holding pattern for the foreseeable future is setting in. Utah now sits on the eastern periphery of an upper-level ridge centered across the U.S. west coast. A closed/cutoff low currently resides south of the ridge over northern Mexico, revealing the beginning stages of a Rex Block pattern.

A Rex Block is characterized by an area high pressure located directly north of a closed low. This configuration slows the eastward movement of air masses and stagnates conditions across a wide area, which is why weather across the state of Utah will not change much for the next 7-10 days. Unfortunately, this means high and dry conditions with valley inversions/haze, fog, and warmer mountain temps. There may be some periods where mid-level flow and temperatures cool just enough to help vent out the valleys at times and reduce poor air quality/haze, but that is completely dependent on the degree troughs/energy graze the state. 

Analyzed 500 mb heights, winds, and temps 18Z 1/12/2026

Rex Block pattern (credit: theweatherprediction)

So when will this blocking pattern dissipate and things become active again?

The ECMWF extended ensemble notes a breakdown in the ridge over the western U.S. come sometime 1/20-1/27/2026 - note the warm colors (500 mb height anomalies) in the animation below dissipating. How much the ridge breaks down and what that means weather-wise for Utah is still uncertain. But long-range models do hint that some degree of activity will return in this timeframe. TBD... In the meantime, Utah mountain and valley areas will be living through weather groundhog day.

ECMWF Extended Ensemble 00Z 1/11/2026: 7 day 500 mb height anomalies (m) 1/12-1/27/2026

ECMWF Ensemble 12Z 1/12/2026: Total precipitation at KSLC 1/12-1/25/2026

Breath of Cold Air

A bright and cold morning across much of Utah, with some fresh snow blanketing portions of the state. Some mountain wave clouds are apparent for areas where the mountains are roughly perpendicular to the northerly winds. Here in the SLV, some of the coldest temps of the season were observed this morning. Lows in the northern Utah valleys were hovering in the upper teens and low 20s. 

GOES-19 East True Color 1/9/2026

SLV and central Wasatch minimum surface temperatures (F) 1/9/2026

Relative to seasonal norms, temps are not that cold, but relative to temps so far this winter it feels colder. Normal lows for this time of year should be in the low to mid 20s in the SLV. Observed mid-level (700 mb) temps are also some of the coldest of the season. The KSLC 12Z sounding noted -17 C at 700 mb, which is not record breaking but is within the 90th percentile. 

1/9/2026 1800Z 700 mb Analysis

1/9/2026 300 mb Jet Analysis: heights, ageostrophic wind, and omega (red=down; magenta=up)

The storm from yesterday has now exited the state, leaving cold temperatures and northerly winds in it's wake. Conditions have now stabilized, with ridging and subsidence building across the region. Winners from the storm include the Cottonwoods and portions of the Oquirrhs. Total storm snow totals range from 10-22" in the Wasatch. SLV bench areas got 1-2". 

Snow Totals Wasatch Mtns as of 1/9/2026 15Z

Snow Totals Wasatch Mtns as of 1/9/2026 15Z

Snow Totals Oquirrh SNOTELs as of 1/19/2026

The N-NW winds and cold lower to mid-level temperature helped induce some lake effect snow showers yesterday afternoon through the overnight hours, which dropped periods of heavy snow from the Cottonwoods/SLV over to the Tooele Valley. The Oquirrhs benefited quite a bit from the lake effect as well. The mid-elevation SNOTEL sites in the Oquirrhs picked up anywhere from 8-10". 

Lake Effect Snow 1/8/2026 - KMTX Radar Composite Reflectivity 1/8/2026 22Z - 1/9/2026 0400Z

Shifted

As is typical, when you think there is confidence in a forecast solution things change. And indeed things have shifted... Timing of some impacts have been pushed back by 4-6 hours, while others have decreased in intensity and duration. 

Snow totals as of 0819 MST 1/8/2026

A less than impressive performance so far from this talked about "storm". Anywhere from wet grass and roads to 0.5-1" of snow accumulation so far across the SL valley. Temperatures never cooled as fast as forecasted and energy and moisture associated with the trough has become a bit more unconsolidated than anticipated. All these factors have led to underwhelming Wasatch Front valley snow totals this morning. The mountains have done alright, with 6-10" so far at the Cottonwood resorts.

GOES-19 East Mid-Level Water Vapor imagery with 500 mb heights, winds, and vorticity overlaid

The main cold front looks to pass over norther Utah by mid-morning Thursday - originally forecasted in the predawn hours -, filtering in some cooler air. Behind this cold front, temperatures will hover near freezing in the northern valleys through the remainder of the day. Another wave of snow showers will fill in behind the front and as the trough axis approaches the area, with a low threat for lake effect snow setting up come late afternoon and early evening when the coldest temps arrive. Mid-level flow is currently NW with additional moisture, so the potential for terrain induced moderate to heavy snow is possible in the Wasatch at times through the day. 

Additional snow accumulations in the SL Valley will likely be light, due to the daytime nature of shower activity, unless heavier rates occur. Models have been trending all over the place with the remainder of the storm - or I guess technically not trending - and as they say "the trend is your friend", so plenty of uncertainty still remains. The mountains are still on track to get anywhere from 10-20", but for the valley accumulations I will just let the remainder of the storm ride out instead of trying to crystal ball any further. 

Something Familiar

The clouds over the mountains this morning are putting on an eye catching show. They are also alluding to shifting conditions. A low lying blanket of clouds extending from the base of Little Cottonwood up canyon and the sprinkling of lenticular clouds across the Wasatch are signs of a change in winds and moisture availability in the atmosphere. 

The clouds this morning can be attributed to southwesterly flow aloft and increasing moisture ahead of a longwave trough and cold front diving south out of the PNW. The trough will begin to push into Utah through Wednesday, bringing winter weather impacts across the state going into Thursday and early Friday. This will be a more traditional or familiar type of winter storm for Utah, with more characteristic northwesterly flow and colder air than previous systems this winter.

Clouds will increase through the morning across the northern half of the state before scattered valley rain/snow and mountain snow showers begin to fill in across the Wasatch Front through the afternoon. Precipitation will initially be focused over the higher terrain through Wednesday evening as upper-level forcing and energy will be weaker. 700 mb temperatures will range from about -4 early to -6 C late Wednesday, bringing snow levels down near 5500-6000'. 

By late Wednesday night into Thursday morning, the main trough energy and cold frontal boundary will progress over the region, aiding in stronger lift/ascent and a period of greater precipitation coverage and rates. During this timeframe, winds will also shift northwesterly, allowing a switch over to a cold air advection regime and greater orographic induced snow. The cooler temperatures will transition rain/snow showers in the valleys over to all snow by early Thursday morning. 

ECMWF 00Z 1/7/2026 four-panel forecast 1/7-1/9/2026: (Top left to bottom right) MSLP/precip and 1000-500 mb thickness; 300 mb gph and winds; ; 500 mb gph, vorticity, and winds; 700 mb gph, RH, temp, and winds

The heaviest snowfall rates in the valley and mountains are expected to occur sometime between the predawn hours to mid morning Thursday. Northwesterly flow will keep upslope showers going into the Cottonwoods through most of Thursday and potentially even into Friday morning. However, the duration of terrain induced snowfall will rely on how long winds remain northwesterly and therefore total mountain snow accumulations will also depend on this. Showers decrease and become more intermittent to scattered in the valley into the afternoon hours, but there is the potential for a lake effect band to setup during this time.

ECMWF ENS 00Z 1/7/2026 10:1 Snowfall Total (in) at KSLC

Model ensemble average (green line above) puts 3-5" of snow in the SLV by Thursday afternoon, but accumulations across the valley will likely be area specific, with localized amounts potentially being higher or lower. Deterministic models differ in placement of higher end totals for snow, with the ECMWF favoring larger totals for the northern and western half of the SLV and the GFS favoring larger totals for the east side and east benches. 

Left: ECMWF 00Z 24hr precip total (in); Right: GFS 12Z 24hr precip total (in) 

Valley snowfall amounts will be heavily dependent on both the timing of the change over from rain/snow to snow and how long winds remain northwesterly versus northerly. Additionally, the formation of lake enhanced snow showers or a lake effect snow band is possible, but there is uncertainty in timing and location of such a feature. Currently, models setup a lake effect band oriented across the western half of the SLV over the Oquirrhs to Tooele Valley mid morning Thursday through the afternoon. Total valley snow accumulations will obviously be heavily impacted by any lake effect snow. If a lake band does develop, impacted locations could see higher totals in the 6-10" range.

UoU GFS Ensemble 00Z 1/7/2026 Total Snow for Alta, UT 1/7-1/13/2026. (credit: UoU Atmo Sciences)

The Cottonwoods look to see anywhere between 10-20" of snow by Friday morning, with localized higher amounts if northwesterly flow sets up nicely and for an extended duration. Because this a colder storm, snow densities will be lighter and cloud microphysics could help push out snow more efficiently. There is good agreement in the extended ensembles that after this next storm things will dry out for quite a bit, so enjoy the fresh powder. A classic inversion setup is forecasted for the northern Utah valley areas going into this weekend and early next week...