Western US Daily Snow
By Alan Smith, Meteorologist Posted 6 hours ago May 28, 2025
Warmer Temps this Week, Cooler and Wetter Pattern Next Week
Summary
A ridge of high pressure is resulting in warm & dry conditions for most of the West this week. The main exception is for areas east of the Continental Divide in WY, CO, & NM where cooler temps & showers/t-storms are expected. Early next week, a large trough will deepen over the West, bringing a few days of cooler & wetter conditions to most of the region.
Short Term Forecast
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Big Picture Overview – May 28 to 31:
The pattern this week has featured a strong ridge of high pressure over the Interior West, which is leading to above-normal temperatures for most of the region. However, frequent backdoor cold fronts and easterly winds are keeping a cooler and wetter pattern going east of the Continental Divide with frequent thunderstorms.
This pattern will continue through the end of the week, while an upper low near the Baja Peninsula will begin to impact the Southwest late this weekend and early next week.
Temperatures will be above-normal for most of the West over the next 5 days, except for areas east of the Continental Divide in Colorado and New Mexico, where temperatures will be near to below normal.
While the high pressure ridge will be the dominant feature over the coming days, we do have a couple of regions that will see more showers and thunderstorms, so let's take a look...
Wednesday (May 28) to Thursday (May 29):
East of the Continental Divide, a backdoor cold front will slide in from the north, stalling along the eastern slopes of the Divide.
Northerly and easterly winds behind the front will bring more moisture and instability into the region, leading to numerous showers and thunderstorms over the eastern ranges and foothills from Wyoming to Colorado to Northern New Mexico.
Stronger storms will be capable of frequent lightning, small to medium-sized hail, and heavy rain, especially on Wednesday.
The Pacific Northwest will remain dry through the day on Wednesday, then a trough will move across the area on Thursday with showers developing across Washington, British Columbia, and Northwest Oregon.
Rain amounts will generally be light to moderate in Washington and Oregon, while British Columbia will see heavier rainfall.
Thunderstorms are also expected on Thursday afternoon across the Interior Northwest, mainly east of the Cascades and coastal ranges.
The Central/Northern Rockies West of the Divide, including Western Colorado, Utah, Wyoming, Idaho, and Montana, will also see some isolated thunderstorm activity in this pattern, though any rainfall looks to be light and spotty.
Friday (May 30) to Saturday (May 31):
Most areas will see warm and relatively dry conditions toward the end of the week, but we will start to see some subtle changes over the Southwest U.S.
A tropical disturbance is expected to develop over the Eastern Pacific in the coming days, while an upper-level low pressure area near the Baja Peninsula will pull some of this tropical moisture northward.
The leading edge of this tropical moisture will reach the Southwest and the Sierra on Friday and Saturday, resulting in a chance of isolated afternoon thunderstorms both days. This initial activity will mainly produce light rain, gusty winds, and occasional lightning as the air will still be relatively dry in the lower atmosphere.
Also, there will be enough lingering moisture along and east of the Continental Divide in Colorado and New Mexico to generate isolated thunderstorms on Friday and Saturday. These storms will likely be weaker and fewer in number compared to prior days, with lighter rainfall amounts also expected.
Sunday (June 1) to Thursday (June 5):
A big change to the weather pattern is coming to the West next week...
In my last post around this time last week, we were anticipating a potentially hot and dry start to June. However, weather models have completely flipped the script on that outlook in recent days, and confidence is growing that a cooler and wetter pattern will take hold instead during the first few days in June.
On Sunday and Sunday night (June 1-2), the upper low over the Baja will move northward into the U.S., bringing in tropical moisture from the south. At the same time, a trough will begin to deepen over the Northwest.
On Monday (June 2) and Tuesday (June 3), the remnants of the southwest Low will move northeast across the Four Corners region while the previous trough over the Northwest deepens over the West Central U.S. This pattern will continue to drive moisture into the Interior West while much cooler air will also filter in.
The European Ensemble Model (average of 50 simulations of this model) is projecting widespread precipitation across most of the West (aside from coastal and valley regions of California), and heavy precipitation across the Northern and Central Rockies.
Warm and unstable air will be in place at the onset of this system, with many areas seeing thunderstorms during the initial wave of moisture. However, much cooler air will arrive by Tuesday and will linger through the end of the week.
The arrival of colder air will also favor high-elevation snow across the Rockies, Sierra, and Cascades, including the potential for heavy snow over the higher terrain near and east of the Divide in the Northern Rockies.
The next map indicates the projected timing of heavier and more widespread precipitation by region. West-wide, the highest impacts look to be from Sunday (June 1) to Wednesday (June 4), with lighter lingering precipitation possible across the Rockies on Thursday (June 5).
Keep in mind that we are far enough away from this event that the timing, intensity, and amounts of precipitation are subject to change as we get closer.
You can view daily and hourly precipitation, temperature, wind, etc. forecasts for any location and elevation, and I would also recommend viewing the Forecast Range charts to get an idea of timing, confidence, and high/low end scenarios.
Extended Forecast
June 6th to 11th:
Heading into the weekend of June 6th-8th and the week of June 9th, confidence in the forecast decreases as there are some model discrepancies.
The European Model (pictured below) is favoring a return to warmer and drier conditions across most of the West.
However, the Front Ranges of the Rockies would still be favored for more seasonal temperatures and afternoon thunderstorms in this pattern, and the North Cascades would be favored for occasional showers as well.
The European Model has the best track record of medium to longer-range weather projections. However, it's still important to examine this weather model and compare it with other models.
The other two major medium/long-range models (the American GFS and Canadian) are not in agreement with the European for the June 7th-11th timeframe.
These latter two models have high-pressure ridging located further east over the Continental Divide, rather than near the West Coast. This would favor drier conditions over the Front Range and potentially wetter conditions over the Pacific Northwest.
Bottom Line – Overall confidence in the pattern is low beyond June 6th. However, most areas are likely to see a warming trend compared to prior days, and depending on exactly how the pattern shakes out, the Front Ranges of the Rockies and the Pacific Northwest are areas to keep an eye on for rain chances.
Thanks so much for reading! Next update on Wednesday, June 3rd.
Alan Smith
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