Utah

Next shot of snow for Salt Lake City this evening as cold front arrives

A fast-moving but potent low pressure system is approaching from the northwest this afternoon, along with a cold front at the leading edge, which will result in a good burst of snowfall across the Salt Lake City area this evening along with snowpacked roads expected for the Monday morning commute.

Conditions are mild and windy ahead of this system this afternoon with temperatures near 40 in Salt Lake City and winds from the south at 20-30mph with gusts to 40mph.  We are also seeing some sunshine this afternoon, but take a look at the latest satellite image, and we can see the system quickly approaching from the northwest, with the band of moisture located over NE Nevada and SE Idaho (image source: College of DuPage).

 

 

Snow is expected to reach Salt Lake late this afternoon as the cold front arrives and will continue through the evening hours with 1-2″/hour rates possible at times.  The prime time for snow will be from about 5pm through midnight, so this will be a short-duration but fairly intense snowfall event.

Snowfall amounts this evening are likely to range from 3-6″ across the SLC area, with higher amounts possible along the eastern benches.  Temperatures will fall to near freezing by the time snowfall begins as the cold front arrives, and will drop further into the low 20s by midnight, and into the upper teens by daybreak Monday. 

There could be some brief melting on road surfaces at the onset of snowfall, but then snow will quickly accumulate all surfaces with areas of icing also possible overnight.  Fortunately, winds will quickly decrease behind the cold front this evening from the NW at 5-15mph, so while there could be some isolated pockets of blowing snow, the overall threat for blowing snow should be minor. 

Partial clearing is expected during the day Monday after early cloud cover with highs reaching the low 30s in Salt Lake City.  This should allow for good recovery on pavement aside from heavily shaded areas.

Rain Changes to Snow in Salt Lake City on Tuesday

A warm southwest flow will remain over Utah on Monday, bringing high elevation snow and low elevation rain to the Wasatch region.  However, changes will arrive on Tuesday as the next organized low pressure system moves across Utah, spreading much colder air into the state with rain changing to snow in Salt Lake City.

Several inches of accumulation will be possible across the Salt Lake City area from Tuesday afternoon through Wednesday, while flash freezing of previously wet roads will be of concern Tuesday evening.

The image below shows this morning’s upper level pattern – we can see a trough of low pressure center just off the Pacific Northwest Coast in Washington (image source: College of DuPage).

 

 

This low pressure system is moving from north to south down the West Coast and transporting cold air southward along with it.  This pattern is actually producing snow across the Seattle area this morning.

This low pressure system and colder air will eventually swing eastward into the Great Basin and into Utah on Tuesday.  Temperatures will remain warm enough overnight tonight for precipitation to remain as mostly rain across the Salt Lake City area, before a cold front arrives Tuesday morning with high temperatures peaking early in the day.

By Tuesday afternoon, we can see the low pressure system is located over the Great Basin and moving into Utah (image source: Colorado Avalanche Information Center).

 

 

Look for a rain/snow mix Tuesday morning for Salt Lake City, before transitioning to all-snow by around noon or shortly after.  Good melting is expected initially with snow that falls Tuesday afternoon, but by late afternoon or early evening, snow will begin to accumulate on all surfaces as temperatures fall below freezing.

In addition, roadways will likely become icy Tuesday evening and overnight as previously wet roadways freeze up.  Temperatures overnight will fall into the low/mid 20s across the Salt Lake City area.

Snow will continue to fall at times (mostly at light to moderate rates) overnight Tuesday and continue well into the day Wednesday, before tapering off Wednesday evening.  Temperatures will likely remain in the 20s for Salt Lake City during the day Wednesday with snow accumulating on roadways.  The Wednesday morning commute will be impacted the most, especially with icy conditions expected under new snowfall from previously wet roads freezing over.

Models are somewhat variable on snowfall amounts with the NAM model coming on a little bit lower, but this seems to be an outlier while the European and American GFS Models are coming in a little higher.  While this is a low resolution model, the GFS image pictured below (image source: pivotalweather.com) is generally in line with our thinking.

 

 

Overall, we expect snowfall totals will most likely end up in the 3-6″ range for Salt Lake City down to Provo, with higher amounts for the benches near the Wasatch Foothills, and lower amounts farther north from Ogden to Brigham City (although Logan is probably closer to what SLC receives).

Following this storm, a chilly airmass well settle into the region on Thursday and Friday before the next system approaches this weekend.

 

High Impact Snow Event for Salt Lake City on Monday

Friday’s storm brought significant snowfall totals to the Wasatch Mountains along with excellent skiing conditions, but impacts across Salt Lake City and the I-15 corridor were much less due to rain falling for much of the event.  However, another potent storm system is approaching from the west with heavier snow amounts expected for Salt Lake City.

The image below is the latest model analyzed upper level pattern from the GFS Model for 5pm Sunday, showing this fast-moving system pushing into Northern California (image source: tropicaltidbits.com).

 

Temperatures are mild again today with temperatures well into the 40s across the urban corridor, but this storm will be moving across Utah from the northwest with a cold front arriving at the leading edge.  Precipitation will be filling in across Northern Utah early Monday morning.  The next image shows the HRRR-model projected precipitation type around 4am tomorrow (image source: weathermodels.com).  Temperatures should be warm enough for precipitation to start as rain or a rain-snow mix across the lower elevations.

 

 

However, thanks to the colder air arriving with the leading edge of this system, we should see a relatively quick change-over to snow across the I-15 corridor as temperatures fall to near freezing.  The next image shows the same model’s projected precipitation type by 7am, which is all-snow across the area (image source: weathermodels.com).

 

 

This will be a relatively short-duration but high-intensity system with most of the snow expected to fall from roughly 7am Monday until sunset for Salt Lake City, with perhaps some lingering light snow showers into the evening.  The onset of snowfall by 6-7am along with the potential for 1″/hour snowfall rates will impact the morning commute Monday as this system comes in strong and fast, with slushy pavement accumulations likely for the urban corridor.  

During the middle part of the day Monday, there may be some melt occurring on the roadways across portions of the metro area since temperatures will be near or just below freezing, but if heavy snowfall rates persist then melting may be minimal.  Across the higher elevation benches, pavement impacts will certainly be more significant.

Snowfall amounts across the I-15 corridor from Provo to Salt Lake City to Brigham City will likely be in the 4-8″ range, with higher amounts possible across the higher elevation benches.  The evening commute will be impacted as well, with the potential for rapid icing on roadways (where melt has occurred) as temperatures begin to drop into the 20s by around or shortly after sunset.

For the Wasatch Mountains, snowfall totals for the town of Park City will likely be in the 6-12″ range with 1-2 feet of snow likely for the ski areas.  This will be another high impact event for the mountains with significant travel difficulties expected.  Strong northwest winds will result in areas of blowing and drifting snow as well.

Snowfall should eventually taper off Monday evening for Salt Lake with overnight lows falling to around 20, but snow will linger well into the overnight period for the Wasatch Mountains.  Schools will fortunately be on a break Monday for Martin Luther King Day, but should be prepared for slick roads Tuesday morning.

Heavy snow for the Wasatch with rain changing to snow in Salt Lake City early Friday

A powerful Pacific storm system is moving into Utah from the west today after dumping heavy amounts of snow in the California’s Sierra Nevada Range (measured in feet) over the past couple of days.  The image below shows this morning’s water vapor satellite imagery, which clearly shows the deep moisture streaming into Utah from the southwest (image source: NOAA). 

 

 

Along with the deep moisture, warmer air from the southwest has also advanced into Utah ahead of this system.  As a result, we will see mostly rain falling in Salt Lake City and the I-15 corridor throughout the day Thursday with temperatures in the 40s.  Snow levels could rise to 6,000′ or higher this afternoon.

Above the rain/snow line, heavy snow will fall in the Wasatch today and tonight, much to the delight of skiers who will enjoy some deep powder conditions on Friday.  For the Park City area, temperatures may be warm enough this afternoon to prevent significant road impacts, though slushy accumulations are certainly possible.  The below image shows HRRR-model projected temperatures this afternoon across Utah (image source: weathermodels.com). 

 

 

The biggest travel impacts with this storm will occur tonight through Friday morning as a cold front arrives.  Road conditions will quickly deteriorate across the Park City area as well as Big and Little Cottonwood Canyons as heavy snow continues to fall as colder air filters into the region.  

The heaviest precipitation will occur through roughly midnight tonight, but additional moisture will linger into Friday as well.  Late tonight, we should see a transition from rain to snow across the Salt Lake City area and the I-5 corridor, with snow expected to impact the Friday morning commute.

Temperatures are projected to be close to freezing Friday morning in downtown Salt Lake City, and the higher snowfall amounts along with more significant pavement impacts will occur across the higher elevation benches across the metro area.  

For snowfall amounts, projections are generally in the 1-3″ range for central Salt Lake City along the I-15 corridor, with higher amounts across the higher elevation benches.  For the Wasatch, the town of Park City could see 7-14″, while the higher elevations of the Wasatch ski areas will likely be in the 1-2 foot range with isolated higher amounts possible.  The next image shows the HRRR model’s projected snowfall amounts across the area over the next 24-hours (image source: weathermodels.com).