Setting Records

I woke up this morning to signs of rain overnight. Windows had droplets, smell of wet ground, and also the subtle smell of the GSL gases. When I checked yesterday morning, the October 2025 monthly total precipitation was already within the top five wettest Octobers on record, so obviously I wanted to check on where SLC ranked this morning after potentially more rain overnight. As of yesterday's and last night's rainfall (0.83"), Salt Lake City has broken the October monthly record for total precipitation (4.31"). This is a fairly large number for only being halfway through the month. With more liquid on the way today through tomorrow and whatever the remainder of the month bring, I am interested in where SLC will end the month at. 

So how much more precip are we going to get with unsettled weather forecasted the next couple of days? 

Wednesday 10/15/2025

An occluded Pacific system/low located over Nevada will translate north and east through Utah today (Wednesday). Utah sits downstream of the low, with deep and relatively moist southwesterly flow across the state. 

GOES East True Color imagery on 10/15/2025 with 500mb analysis overlaid

The Pacific air mass associated with the system has been highly modified and the stronger baroclinic characteristics of the storm have been somewhat muted. However, a cooler air mass still remains under the center of the low, with an attendant cold front now located over central and southwestern Utah. As the low progresses E-NE through Utah on Wednesday, this cold front will move across the Wasatch front late morning into the afternoon. Cooler air along with precipitation will fill into the state as the cold front moves over. Rainfall will generally be light to moderate for areas, with a few opportunities for heavier showers if clouds part and the sun is able to destabilize things a bit. 

Thursday 

The trough axis (center of the trough) looks to pass over northern Utah sometime overnight Wednesday into Thursday morning. By this point, the main moisture field with be exiting the state but trailing wrap-around moisture and energy will filter in from the W-NW. Cooler mid to upper-level temperatures combined with surface heating will aid in some cold-core shower/thunderstorm development through the day. Most precipitation will be light and scattered. 

ECMWF 00Z 10/15 four-panel forecast for 10/16/2025 @ 12Z: (Top left to bottom right) MSLP/precip and 1000-500 mb thickness;700 mb gph, RH, temp, and winds; 300 mb gph and winds; 500 mb gph, vorticity, and winds

Mid to upper-level winds look to shift NW on Thursday, bringing more favorable conditions for some scattered upslope showers in the mountains. However,  Thursday morning 700 mb temperature drop to -4 to -5C under the core of the low, so the snow line will likely be somewhere near 6500-7000' early Thursday morning before rising to around 7000-7500' by the afternoon. 

ECWMF 00Z 10/15/2025 forecasted 10/16 12Z 700mb temperature

Another few inches of snow for the higher elevations across most of the state. Hard to say exactly how much the Cottonwoods will get due to the fairly disorganized nature and unfavorable conditions for much of the storm. However, most guidance puts down about 3-6" of snow for locations > 8000'.

ECMWF 00Z 10/15/2025 forecasted total precipitation (in) 10/15-10/17/2025 00Z

All said and done SLC is forecasted to get anywhere between 0.5-1" of additional rainfall between Wednesday and Thursday, with the highest accumulations expected along an arc spanning the west to north to east perimeter of the SLV. Much of the central SLV may get shadowed due to the flow direction associated with the storm.  

Beyond 

ECMWF 00Z 10/15 four-panel forecast for 10/19/2025 @ 06Z: (Top left to bottom right) MSLP/precip and 1000-500 mb thickness;700 mb gph, RH, temp, and winds; 300 mb gph and winds; 500 mb gph, vorticity, and winds

Conditions dry out by Friday, but cooler air remains in place across the state, with highs in the upper 50s for the northern valleys. Temperatures moderate each day going into the weekend as a ridge builds over the Great Basin. Next storm looks to impact the state early next week. However, there's plenty of uncertainty about the track and strength, and models have been trending drier and warmer with this storm. So far, I have been enjoying the relative storminess intermixed with periods of nice fall weather. Still hasn't got too cold yet..

KSLC observed and forecasted temperature (F) 10/15-10/22/2025

Mid-week Low

No, I'm not talking about that feeling you get Wednesday afternoon after eating a greasy cheeseburger at your desk. A low pressure system looks to track across Utah by the middle of this week. 

I woke up this morning and saw some cumulostratus clouds streaming south to north quite quickly across the sky. Pretty intuitively, I gathered that means the winds at cloud level were moving fairly fast out of the south. Temps were also hovering near 50F, which was quite warm for an overnight low, considering the high yesterday didn't make it out of the 50s. After a clear, calm, and dry day yesterday, where winds were W-NW and temps were cool, the observations this morning make me think changes are coming.

Currently

GOES West water vapor imagery 10/13/2025

The satellite water vapor channel uses electromagnetic radiation absorbed and emitted by water vapor to detect varying amounts of moisture in the atmosphere. The water vapor channel is useful when trying to identify circulations in the atmosphere, due to the way water vapor acts as a tracer for atmospheric motion. Imagery from this morning (10/13/2025) reveals a broad upper-level low sliding south down the U.S. Pacific coast. Some moisture is also noted, by the cloud field and brighter colors, moving SW to NE across Arizona into southern Utah. 

500mb gph, wind obs, and absolute vorticity (shear+curvature+earth)

If we look at this morning's current upper-level 500mb analysis chart, we can see the broad spinning low/trough along the U.S. Pacific coast noted by the higher values of vorticity (warm colors) and the cyclonic curvature (counter clockwise) in the height and wind field. 

Monday

Today - Monday - Utah sits downstream of the Pacific trough, putting the state under southerly to southwesterly flow, hence the cloud movement this morning. The deep layer southerly flow is clearly evident in this morning's sounding from KSLC as is the warmed mid-level temperatures - from about -2C at 700mb yesterday to about +2C at 700mb this morning.

KSLC 12Z 10/13/2025 sounding skew-t: temp (red), dew pt (green), and winds

A slug of moisture and associated energy (short-waves) will move south to north into southern Utah going forward through the day, bringing the potential for scattered showers and thunderstorms. There's the possibility of a few stronger thunderstorms across SE Utah Monday afternoon due to a combination of deep layer wind shear, low-level moisture advection, and daytime heating. 

Left: CONUS 700 mb gph, winds, RH, and temp; Right: Intermountain West 700 mb gph, winds, temp, and RH - blue dashed lines note short-waves, red arrows note direction of moisture transport

Winds will become breezy out of the south for areas by Monday afternoon, but temps should warm 10-15 degrees compared to yesterday's highs. Northern Utah and the Wasatch Front will likely remain dry, with mostly sunny conditions in the morning and increasing clouds come the afternoon. Highs in the upper 60s for the SLV. By later afternoon/evening this is an increased opportunity for a shower or storm as moisture from down south rotates northward. 

Tuesday

The Pacific trough is forecasted to dig south and become a closed low by Tuesday. This means Utah will continue to to be on the down stream side of the trough with southerly to southwesterly winds from the surface to the upper-levels. Bouts energy and moisture will continue to rotate northward through the state on Tuesday, creating periods of scattered showers/storms. Most shower activity looks to focus Tuesday morning. So Tuesday is looking like a close repeat of Monday for most areas of the state, with some minor variations. Likely another mild-ish day across the Wasatch Front, with breezy southerly winds, a few showers possible Tuesday morning then a mix of clouds and sun. 

ECMWF 00Z 10/13 four-panel forecast for 10/15/2025 @ 00Z: (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 

Wednesday-Thursday

Tuesday evening into Wednesday things look to get a bit more interesting. The trough finally begins to make eastward progress and pushes into Utah, bringing a cold front and spreading precipitation over most of the state. Currently, it looks like a cold frontal boundary will slowly make it's way across Utah over the course of Wednesday. How this boundary progresses along with the movement of the upper-level low will determine precip location, amounts, and timing. But as of now, the most consistent precip for northern valley areas looks to be Wednesday morning into the afternoon. 

The air associated with the cold front has maritime polar origins, but by the time it gets to the state it will be highly modified - not as cold. Nonetheless, the colder mid to upper level temps will drop temperatures in the 40s and 50s in the valleys and drop snow levels down around 7500-8000' by Wednesday afternoon/evening in the mountains. Another few inches of snow accumulations possible for the high elevations by Thursday morning.

The trough exits the state by late Thursday, but not before delivering some wrap around precip, focused over northern Utah, Thursday morning and potentially in the afternoon.  

ECMWF 00Z 10/13 four-panel forecast for 10/15/2025 @ 18Z: (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 

ECMWF 00Z 10/13 forecast loop: 6-hr precipitation accumulation 10/15 00Z - 10/17 00Z

Beyond

As of now a ridge builds over the Intermountain West Friday through the weekend, bringing another period of dry and warmish weather. Should be a fairly nice weekend across Utah. Happy to break the weekend storm cycle before it got too strong of a hold. Hints of the next noteworthy system early next workweek.

Wet'n Wild

The Salt Lake Valley woke up this morning to an already decent - by Utah standards - rainfall. Most areas accumulated .2-.3" of liquid as a wave of showers passed over the valley in the predawn hours Friday

Precip Totals SL Valley 10/10/2025 @ 0900 MDT

Current Conditions

As seen by the water vapor satellite imagery below, Utah is sandwiched between a large scale upper-level ridge over the central U.S. and a large scale trough edging onto the NW U.S. Pacific coast. This setup has created a corridor of southerly to southwesterly winds from the surface to the top of the troposphere, facilitating the transport of tropical moisture from the remnants of the tropical depression Priscilla north through the Desert SW up into the Intermountain West. The broad swath of moisture surging north from the Mexican Baja/Priscilla and the broad spinning upper-level low/trough off the NW U.S. Pacific coast is evident in the water vapor satellite imagery below. 

GOES West Water Vapor Imagery 10/10/2025

A short-wave trough - a ripple embedded within large scale pattern - moved across Utah and Colorado overnight through this morning, bringing showers and storms. Short-wave troughs are associated with vorticity maxima (areas of cyclonic spin), cooler air aloft, and the energy responsible for creating clouds and precipitation. The the short-wave trough axis is noted by the dashed blue line in the figures below. The upper level ridge axis over the central U.S. is noted by the dashed red lines. 

Left: 500 mb gph, winds, and temp; Right: 700 mb gph, winds, temp, and RH

Friday into Saturday morning

Going forward into Saturday afternoon, multiple ripples or pieces of energy (short-waves) will progress approximately SW to NE across Utah. Combined with access to the deep moisture field - thanks to Priscilla - and support from some jet-streak dynamics, these pockets of energy with bring waves of rain showers and storms. Precipitable water across the region is forecasted to be near all time record levels for this time of year, with > 1" for portions of the state, particularly SE Utah.

ECMWF 00Z 10/10/2025 forecast for 10/10 @ 18Z: Left: precipitable water (in); Right: precipitable water % anomaly

Northern Utah

Northern Utah will likely get a bit of a break from the consistent precip after Friday morning, with a mix of clouds and sun through most of the day. Temps will remain mild for early October. A spotty shower or thunderstorm is not out the question for the SL Valley, particularly later this afternoon, but as noted by the warm colors in the water vapor imagery below drier air will intrude into the area before additional moisture resurges north later Friday into Saturday.

GOES West Water Vapor Imagery 10/10/2025

Southern Utah

Southern Utah looks to get periods of showers and storms through Friday afternoon before the most consistent precipitation arrives late Friday into Saturday. Flooding and flash flooding will be a major threat for areas across southern Utah. Mountainous areas will also potentially see enhanced precipitation. By Sunday, 1-3" of liquid is forecasted, particularly for SE Utah, the Book Cliffs/Tavaputs, and Pine Valley mountains.

 Left:  ECMWF 00Z 10/10/2025 forecasted Total precipitation (in) for 10/12 @ 12Z; Right: WPC Flash Flood Risk

Saturday Morning-Night

Last Major Tropical Moisture Impacts

The figure below shows multiple forecasted fields on Saturday 10/11 @ 12Z for four different levels in the atmosphere (top left to bottom right: surface, 300-200mb, 500mb, and 700mb). Areas are marked to indicate regions of heaviest precip, enhanced lift due to upper-level dynamics, trough axes, and cold front boundary, respectively. 

ECMWF 00Z 10/10 four-panel forecast for 10/11/2025 @ 12Z: (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 

Upper-level Trough and Cold Front

By late Saturday afternoon/early evening, the attention pivots to the upper-level trough and associated cold front moving into northern Utah. There's a decent amount of baroclinicity with this trough, indicated by the sharp temperature gradient/cold front in the forecasted 700mb chart below, and the strong jet-streak noted in the 300-200mb chart oriented roughly parallel to the frontal boundary. A combination of frontogenesis and upper-level lift coinciding with the left front exit region of the jet streak could create for some interesting conditions across the Northern Wasatch Front Saturday evening/night. 

ECMWF 00Z 10/10 four-panel forecast for 10/11/2025 @ 12Z: (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 

Without trying to add every available plot and piece of information to this post, I will try and summarize. Storms and shower activity will fill into northern Utah late Saturday afternoon into the evening. The front is forecasted to move through sometime between 1700-2000 MDT. Precipitation will be most consistent and heaviest during this period before decreasing through the first half of Saturday night. From the met variables in play that I mentioned previously, there's a good opportunity the Wasatch Front gets in on some thunder and lightning activity with a possible stronger storm. Maybe even some thunder-snow and graupel for the higher elevations in the mountains. 

UoU LCC guidance: Alta total snow accumulation (in)

Snow levels will drop down to 6500-7000' by Saturday night as colder air filters in and heavier showers lower the wet-bulb freezing level. With the wind shifting NW for a short period overnight Saturday, the Cottonwoods look to pick up a few inches of the white stuff by Sunday morning. So for all the addicts that will be shaking in their beds Sunday morning, get out into the mountains on Sunday and get a good snort in.

Sunday into the Beyond

Unfortunately (or fortunately), the pattern shifts quickly, reverting winds back westerly and then to southwesterly in a 24-36hr period. Unfavorable flow, dissipating moisture, and warm air advection will shut down the upslope flow in the Cottonwoods. However, next workweek looks to provide a few more opportunities for liquid and mountain snow. Is all this active weather just an early season tease or will it continue into the late fall and winter? May be time to rub the forecasting magic eight ball... 

Inversion Lite

I noticed a light haze lingering in the Salt Lake Valley both Tuesday and Wednesday of this week. It's becoming that time of year where the sun angle is decreasing precipitously, and any cold air is starting to pool more stubbornly in the valley. Up high on the east bench, the inversion and associated aerosol layer was clearly visible. 

This picture was only taken at about 5600-5700' ASL - which is about 1300' above the valley floor - and it seems the top of the inversion/aerosol level is about the same height. To verify, I took a look at the 00Z sounding from KSLC, which happened to approximately coincide with the timing of this photo. 

Left: KSLC 00Z 10/8/2025 sounding skew-t; Right: KSLC 00Z 10/8/2025 sounding tabular data

The 00Z KSLC sounding very clearly indicates a shallow inverted layer at about 1656-1728 m ASL or about 403 m (1342') above the valley floor. This indicates the hazy layer was at about the same level as the level the photo was taken. 

By today (Thursday), we won't be worrying about any other inversions or haze for awhile. Winds will pick up out of the south as the upper-level pattern begins to shift and the airshed will mix out. More unstable conditions are expected going forward, with the big story continuing to be the multiple rounds of stormy activity this weekend. Utah will get the whole gambit of weather conditions including tropical moisture, thunderstorms, and higher elevation snow. Flooding will be a major threat for mountainous areas and southern parts of the state.

Left: WPC Excessive Rainfall Outlook for 10/10/2025; Right: WPC Forecast Chart Valid 10/10/2025

One-Two Punch

A hurricane, a cold front, and a split jet stream walk into a bar... As far as Utah weather is concerned, this weekend looks quite interesting. The weather will be playing 3-D chess, and if conditions come together areas of the state will see another big rain maker, storms, strong winds, and mountain snow to top it off. 

The Next Few Days:

Before the excitement of this weekend, Wednesday will be another great fall day, with sun and mild temps. Thursday will bring the opportunity for scattered showers to edge up into southern and central Utah, focused across the higher terrain. The Wasatch Front valleys will likely eek out another nice dry and warm day, with a spotty shower possible in the Wasatch mountains. My suggestion is to get out and enjoy the weather before conditions go downhill Friday into the weekend. 

The atmosphere and earth is an interconnected system, with no one atmospheric or surface phenomena being independent from another. Hurricane Priscilla currently spins just to the south of the Baja Peninsula of Mexico. In the next few days it will slowly progress N-NE before decaying into a tropical depression and ultimately impacting Utah weather a thousand miles away.  

The Late Week to Weekend:

At the moment, an upper-level trough is digging south off the west coast of British Columbia and the PNW. The trough will continue to dive south over the next 24-36 hrs before closing off and stalling briefly off the N. California/Oregon coast by late Thursday into Friday. During the same period, an upper-level ridge will build over the southern Plains and central CONUS. The anticyclonic (clockwise) winds around the ridge and the cyclonic (counter clockwise) winds around the trough will create a corridor of southwesterly mid to upper-level winds across the Southwest and Intermountain West. Additionally, a split polar jet stream (southerly and northerly branch) will make for some enhanced upper-level dynamics/lift. It's these southwesterly winds and enhanced dynamics that will help tap into the tropical moisture and energy of Priscilla, bringing it north into the Desert SW and Utah, and creating an environment conducive for extended moderate to heavy rainfall over locations. 

ECMWF 00Z 10/08 two-panel forecast for 10/10/2025 @ 12Z: (left to right) 500 mb gph, vorticity, and winds; 700 mb gph, RH, temp, and winds 

There's a bit of uncertainty as to exact interplay between the upper-level trough, ridge, and Priscilla, with small changes in any one of these atmospheric players changing the forecast down the line. However, simplifying this complex situation, the most recent guidance does offer a general depiction of what will occur this weekend:

ECMWF 00Z 10/08 two-panel forecast for 10/08/2025 12Z - 10/13/2025 12Z: (left to right) MSLP, 1000-500 mb thickness, and precipitation; 700 mb gph, RH, temp, and winds 

Thursday

A combination of moisture transported around the upper-level ridge across the south-central CONUS and moisture tapped from Priscilla will be transported northward across the Desert SW and into Utah. Scattered showers and storms possible, mainly focused across the southern tier or the state in the afternoon. SL valley temps near 80F. 

Friday

1st act: Moisture from Priscilla is tapped further, bringing more widespread showers/storms into Utah, with the greatest coverage across the southern two thirds of the state. SE Utah looks to see the heaviest and most consistent precip, with the threat of flooding. Potential for some thunderstorms across the Wasatch Front. Winds strengthen out of the S-SW for SW and central Utah desert areas. SL valley temps upper 70s. 

Flash flood potential

Saturday morning/afternoon

The eastward progression of the Pacific trough speeds up and moves inland across the Great Basin region. Pacific moisture and a maritime polar airmass begin to combine with the tropical moisture from Priscilla. At this point, northern Utah has remained removed from the bulk of precipitation. Maybe a bit of a lull in shower and storm activity across the state, but still ongoing for areas. SL valley temps upper 70s. 

Saturday evening/night 

2nd act: A cold front and associated precipitation field moves across northern Utah, bringing the most consistent and heaviest precip to the Wasatch Front. As is typical, the most favorable period for precipitation in the valleys and particularly the mountains will occur when mid-level winds shift NW, which should occur sometime Saturday evening/night. This will also be the same period when colder air advects into the state, lowering the rain/snow line down to about 6500-7000'.

Sunday

Cooler drier air moves in as the trough exits the state to the east. Maybe a few lingering valley rain or mountain snow showers in the morning before drying out by the afternoon. SL valley highs in the 50s. 

ECMWF 12Z 10/8/2025: Total precipitation (in) 10/8 - 10/13

Beyond

May provide some updates on the storm event this weekend as we get closer. Otherwise, conditions beyond this weekend into next workweek also look intriguing, with active, wet, and cool conditions possible. For those already foaming at the mouth about snow in the Wasatch, you may start convulsing by mid to late next week. We'll see...

Prayers Sorta Answered

Utahn's prayers have finally been answered... somewhat. The storm that impacted the state the first half of this past weekend (10/3-10/4) is one that will go down in the record books. The KMTX radar loop from the morning of 10/4 reveals a cyclonically spinning precipitation field over northern Utah. Much of the higher radar reflectivities are skewed by "bright banding" - higher reflectivities from melting snow within the cloud - but in general the level 2 scan identifies a broad area of moderate to heavy rainfall with lower correlation coefficient values indicating the melting layer (bright banding). As far as some metrics go, this storm was not the "strongest" October system Utah has seen, but it was the most moisture rich. The storm track aligned in such a way a prolonged and consistent rain event played out in northern Utah valley areas.

Right: KMTX level 2 scan reflectivity 10/4/2025 0821-0848 MDT; Left: Level 2 correlation coefficient

To get straight to the point, on 10/4/2025 Salt Lake City observed the 2nd greatest daily total precipitation (2.47") since records began in 1874. A table of the top 10 daily total precipitation accumulations for SLC is given below. The only date to out-rain this past Saturday (10/4/2025) was back on 5/3/1901. Even then, the observations were taken in downtown SLC in 1901 and not at Salt Lake City International Airport (KSLC), so there could be an argument whether or not 10/4/2025 is the first. 

I think we all can agree - vegetation and people alike - that the record amount of rain this past weekend was much enjoyed and appreciated. It's been such a lackluster year for precipitation in Utah. We just ended the water year on Oct. 1 - water year spans a year starting and ending on Oct. 1 - at 10.48". This is the 8th driest water year on record as shown in the table below.   

As far as yearly precipitation (Jan. 1 - Dec. 31), prior to this storm, SLC was 4.04" below normal for year to date precipitation. After the storm, SLC is now only 1.51" below normal or 1.56" depending on if you compare against 10/5 or 10/6. This comeback is all thanks to the event/storm total of 2.62" between 10/3-10/5. 

This Week's Outlook:

Now that the storm and rain is behind us, conditions will be dry with temperature moderating a bit each day going late into this workweek as a ridge builds back over Utah. The Salt Lake City Valley may actually kiss 80 F by Thursday. It is looking to be a beautiful few days of mild fall weather so enjoy. 

Things look to deteriorate again by the end of the week/weekend as a Pacific tropical system and fairly deep trough off the U.S Pacific coast interact. Definitely lots of uncertainty as to what will occur, but models are still trending on bringing remnants of the tropical system into Utah combined with impacts from the trough and associated cold front. 

ECMWF 00Z 10/6 four-panel forecast for 10/11/2025 @ 00Z: (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 

It could be a one two punch this Fri-Sun, with more active and cool and wet weather on the way for Utah. Flooding will be a large threat for areas of the state as the extra-tropical nature of this weekends storm and precipitation enhancement from topography could produce extended heavy rainfall. Details are likely to change, but this could be another big rainmaker for Utah and early season mountain snowmaker depending on the storm track. 

The Winds of Change

A beautiful warm fall day with crystalline blue skies is expected for Thursday. Winds should be a bit breezy out of the south this afternoon with highs near 80 F for most Wasatch Front valley areas. Go take a look at the fall colors in the mountains before they disappear. Starting tomorrow - Friday - weather conditions will begin to deteriorate as our most potent storm in some months will impact Utah. 

An approaching upper-level low swirls just off the NW U.S Pacific coast on 10/2/2025, with clear skies across Utah

Left: 10/2/2025 16Z 500 mb gph, winds, and temperature: Right: ECMWF10/2/2025 max surface temperature

As of today, a bullseye low swirls just off the NW U.S Pacific coast, with Utah still under protective edge of a dome of high pressure. Utah weather will remain relatively quiet through Thursday, but Friday winds will increase out of the south ahead of the approaching low/trough, marking the beginning of change. Southerly winds will increase Friday morning through the afternoon as the storm/trough moves east across the Great Basin. There is a marginal potential for some blowing dust being generated across the central Utah deserts as winds look to gust 45-50 mph Friday afternoon. Whether or not dust gets generated or makes it up to the Wasatch Front tomorrow is still up in the "air". However, we will see some gusty southerly winds in the SL Valley. Additionally, a few high based showers or thunderstorms are possible Friday afternoon, which could also generate some gusty winds themselves. 

ECMWF 00Z 10/2 forecast for 10/4/2025 @ 00Z: (left to right) 500 mb gph, vorticity, and winds; Surface wind gusts (mph) 

By Friday evening/night, the main act will begin. The trough and cold front looks to move over Utah Friday night into Saturday, shifting winds more W-NW and bringing increased rain shower and storm activity. The most consistent precipitation along the Wasatch Front is expected as winds shift W-NW Saturday late morning to early afternoon, particularly in the mountains. As colder air moves in along the Wasatch Front on Saturday, daytime valley highs will only top out in the 50s and snow is forecasted for upper elevations in the mountains across the state (> 8000'). The Uintas look to be the winner in terms of potential for most snowfall accumulation, so for those with plans to go for a last minute leaf peep be very warry. For anyone that has been itching for prototypical fall conditions to get in the spirit of the spooky season, the cool and wet conditions on Saturday may fit the bill. 

ECMWF 00Z 10/2 forecast for 10/5/2025 @ 00Z:  (left to right) Total precipitation (in); Total snowfall (10:1 inches)

GFS 12Z Alta total snow accumulation plume

The system quickly moves east of the state by Sunday. However, a reinforcing shot of cooler air dives down south into the state behind the system, keeping things a bit unsettled. The combination of cooler upper-level temperatures and residual moisture could spawn a spotty shower or two on Sunday, particularly over the higher terrain in afternoon. 

ECMWF 00Z 10/2 forecast for 10/5/2025 @ 00Z:  (left to right) 500 mb gph, vorticity, and winds; 700 mb gph, winds, RH, and temperature

Beyond Sunday, the weather next workweek looks interesting but is layered with levels of uncertainty. Lingering cool air and a stalled frontal boundary across central Utah will keep things cool and may facilitate some periods of shower activity through early next week. A brief respite is possible between systems mid next week before a number of possible scenarios play out. 

As of now, there are hints of Utah being impacted late next week from the remnants of a tropical system from the eastern Pacific. There is plenty of uncertainty associated with this forecast, but it does seem as if models are trending towards bringing the extra-tropical system into the Desert SW. If this scenario plays out, a broad area of relatively heavy rainfall could impact the entire state of Utah, posing a risk for flooding in some areas. Nevertheless, this scenario is still out in the forecast fantasy land and details will most certainly change going forward. But is still something interesting on the radar... 

ECMWF 00Z 10/2 forecast for 10/6/2025 @ 06Z: MSLP, 1000-500 mb thickness, and 6-hr precipitation

A brief overview of sensible weather conditions this weekend through next week. Obviously this forecast should be taken with a heavy grain of salt, specifically once you get 3-5 days out from now (10/2). Either way, it looks like the last bit of 80 degree days for the year will be today and tomorrow. It will be a long shot if we warm back up enough to hit 80 in the next 7-10 days, but not totally out of the question.

ECMWF 00Z 10/2 forecasted surface summary overview