Western US Daily Snow
By Alan Smith, Meteorologist Posted 6 hours ago July 15, 2025
Thunderstorm Activity on the Rise, but so are Wildfires and Smoke
Summary
An uptick in thunderstorms is expected across the West this week as a potent trough tracks across the Northern Rockies, while monsoon moisture increases across the Southwest. Some areas will see heavy downpours this week, but lightning-triggered wildfires are also a concern. Wildfires have been growing in coverage & intensity recently, with smoky conditions across the Southwest in particular.
Short Term Forecast
Helpful Links:
Wildfire and Smoke Update:
This past weekend was a rough one across the Southwest as a fast-moving wildfire destroyed the historic Grand Canyon Lodge on the north rim, along with 50-80 other buildings. Fortunately, everyone in the area was evacuated well ahead of time, but it's still heartbreaking to see the destruction of an iconic place.
Numerous other large wildfires have been burning across Southern Utah and Western Colorado, and fire activity is beginning to pick up across the Northwest as well.
Be sure to utilize our air quality and smoke maps (links above) to avoid the smoke this summer.
Smoke (Sky) Forecast for 6:00 PM on Tuesday:
Let's hope that some of these areas will see help from monsoon rains later this week, without the burn scar flooding side effects...
5-Day Temperature Outlook:
Relative heat relief (by July standards) can be expected across portions of the Northern Rockies this week as multiple cold fronts move through, while an increase in monsoonal moisture will lead to "cooler" temperatures across the Southwest.
Above-normal temperatures are expected over the Northwest, but temperature anomalies will not be extreme.
Tuesday (July 15):
There are two weather features that will lead to active weather across portions of the West.
First, a potent shortwave trough will move across the Northern Rockies from west to east, and a cold front will also push through Montana and into Northern Wyoming from north to south.
Pacific moisture arriving with this system will contribute to widespread showers with significant rainfall across Montana with some areas picking up more than an inch of rain.
Thunderstorm chances will be highest over Southern Montana and Northern Wyoming, with stronger storms capable of producing heavy rain.
The second feature will be the North American Monsoon, with an uptick in moisture over Southern Arizona and Southwest New Mexico leading to scattered thunderstorms. Stronger storms will be capable of producing heavy rain, along with possible flash flooding in dry washes and recent fire burn scars.
Limited levels of monsoonal moisture will also start to stream northward, leading to isolated to scattered thunderstorms across the Great Basin and Central Rockies. Storms in the yellow-shaded areas will generally produce light to moderate rainfall.
Fire danger will also be higher across these regions due to the potential for "dry" thunderstorms, which can produce frequent lightning, strong winds, and limited rainfall, which increases the potential for lightning-triggered wildfires.
Wednesday (July 16):
A cold front will slide into Northern and Eastern Colorado, and eventually New Mexico, with moisture increasing along and east of the Continental Divide. This will lead to an uptick in thunderstorms across the eastern ranges of the Rockies from Southern Montana to New Mexico, with heavy rain possible.
Monsoonal moisture will continue to increase west of the Divide across New Mexico and Arizona, with more numerous thunderstorms expected, some of which will produce heavy rain with a risk of flash flooding.
Scattered thunderstorms can be expected across the Central Rockies, Great Basin, and Southern California Mountains. Localized downpours are possible in these regions, but some storms will only produce light rain and strong winds, which could exacerbate ongoing wildfires and increase the potential for new fires.
Thursday (July 17):
Monsoonal moisture will increase across Northern Arizona and New Mexico, and Southern Utah and Colorado, with the highest thunderstorm coverage expected south of I-70.
Storms have the potential to produce heavy rainfall across this region with an increased risk of flash flooding in slot canyons, dry washes, and recent fire burn scars.
A noticeable uptick in lightning activity is also expected across the San Juans and Elks in Western Colorado compared to prior days.
Elsewhere across the West, thunderstorm coverage will be more isolated to scattered in nature, though Glacier National Park could see higher coverage of showers and storms as a trough pushes into the Northern Rockies.
Modest thunderstorm coverage is also possible over the Northern Colorado Front Range and the Uinta Range in Utah.
Friday (July 18):
Two low pressure areas over the Southwest will continue to funnel monsoonal moisture into the Southwest with thunderstorm coverage favoring the Four Corners region as well as the mountains around Vegas and into Southern California. Heavy rainfall will be possible throughout these regions, along with a risk of flash flooding in vulnerable terrain.
Thunderstorm coverage will be more isolated across the Northern Rockies, though the eastern-most ranges of Montana and Wyoming could see greater thunderstorm coverage as a cold front moves through.
Saturday (July 19):
Another active day is expected across the Southwest and Southern Rockies with thunderstorms and heavy rainfall potential favoring Northern Arizona, Utah, Colorado, and New Mexico.
A relative uptick in coverage is also expected across portions of the Great Basin and Northern Rockies with isolated to scattered thunderstorms. These areas will likely see a mix of wet and dry thunderstorms, with stronger storms capable of heavy downpours.
Extended Forecast
July 20-28:
Next week, another trough will move across the Northern Rockies with cooler air arriving, while temperatures will heat up over the Southwest and Southern Rockies. The west coast of California is also favored for below-normal temperatures.
The trough moving across the Northern Rockies is expected to weaken the monsoon, with below-normal precipitation favored across the Southwest. Near-daily rounds of thunderstorms will still occur across this region, but coverage and rainfall amounts may be lighter than what is typical for late July.
Above-normal rainfall chances are favored across Washington, Northern Idaho, and Montana in NOAA's 6-10 day outlook from July 20-24 in response to the trough that is projected to move through.
Looking further out, a weaker-than-normal monsoon is projected from July 22-28 with below-normal precipitation favored over the Southwest and the Central Rockies. The far Northwest U.S. may continue to see periods of showers and thunderstorms as disturbances are favored to track along the Canadian border.
Some longer-range projections have hinted at a strengthening monsoon heading into early August, but that is still a good ways out, so we'll see how this looks as we get closer.
Thanks so much for reading! Next update on Wednesday (July 16).
Alan Smith
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