5-Day Big Picture Overview:

Moisture will decrease across most of the West over the next 5 days, while an amplified ridge/trough pattern will set up.

A strong ridge will develop along the West Coast, resulting in a significant warm-up, while a trough over the Interior West and North Central U.S. will support a cooler NW flow over the Northern and Central Rockies, where below-average temperatures are expected. 

5-Day Regional Forecast Breakdown below as follows...

• Colorado
• Utah
• Southwest
• California/Sierra
• Pacific Northwest
• Northern Rockies
• BC Interior & Canadian Rockies

COLORADO

Wed-Fri – Dry and breezy conditions will prevail statewide. Wednesday will feature the strongest wind gusts and also the highest fire danger statewide, but Thursday and Friday will still be brisk as well, especially above treeline.

Wednesday will be on the hotter side across the lower elevations, then a cold front on Thursday will bring much cooler temperatures, before heating up again on Friday afternoon.

Sat – Another cold front will slide in from the north, bringing cooler temperatures (Front Range & Plains especially) along with a chance of thunderstorms. Storm chances will primarily be confined to the Front Range and Sangres, along and east of the Divide. However, the San Juans also have a chance of thunderstorms as some moisture sneaks in from the south.

Sun – Shower and thunderstorm chances will increase statewide as a trough approaches from the northwest, while moisture also increases from the south. For now, the highest threat of lightning looks to be along and west of the Continental Divide and south of I-70 but this could change as we get closer.

There is also a better chance of meaningful rainfall with showers/storms in this pattern, including locally heavy downpours.

UTAH

Wed-Fri – A cooler and drier airmass will settle into place over Northern Utah, resulting in very nice conditions overall, though winds will be gusty. Cooler air will also sneak into Southern Utah briefly on Thursday, before heating back up again on Friday. Fire danger will be highest across Southern Utah for the rest of this week.

Sat-Sun – Northern Utah will stay dry this weekend with warm but not terribly hot temperatures for the lower elevations. Overall, it's shaping up to be a very nice weekend.

Across Southern Utah, some moisture will sneak in from the south, resulting in a chance of afternoon thunderstorms both days. Saturday's thunderstorms look to be "dry" storms with gusty winds and little to no rain, which will also add to the fire danger.

On Sunday, low-level moisture should increase compared to Saturday, with a mix of wet and dry thunderstorms possible, but fire danger will remain elevated. 

SOUTHWEST

Wed-Thu – Hot, dry, and breezy conditions will prevail, resulting in high fire danger across NM and AZ.

Fri – A backdoor cold front will push into NM from the north and east, and a strong surge of low level moisture will also arrive from the east. This will result in a good chance of afternoon thunderstorms across Central and Eastern NM, while isolated thunderstorms are also possible across Southern AZ.

Sat-Sun – Subtropical moisture will arrive from the south, resulting in a better chance of thunderstorms across both NM and AZ. Coverage will primarily favor higher-elevation terrain, as well as lower elevations east of the mountains in NM.

The setup looks to feature a mix of wet and dry storms, with some storms capable of locally heavy downpours, while others could produce dry lightning and elevated fire concerns.

CALIFORNIA/SIERRA

Wed-Thu – Overall, a warming and drying trend can be expected with temperatures heating up across the lower elevations. Winds will remain gusty in exposed terrain but will gradually decrease from Thursday onward compared to recent days.

Fri-Sun – The warming trend will continue as high pressure builds along the West Coast, and the first true heatwave of the season will take hold over the lower elevations.

A little bit of moisture will sneak into the High Sierra from the southeast, resulting in a chance of isolated thunderstorms each afternoon, so heads up if you have high-elevation hiking or climbing plans.

PACIFIC NORTHWEST

The wet pattern experienced in recent weeks is coming to an end, and a stretch of beautiful weather awaits with dry conditions expected from Wednesday through Sunday. Skies will remain mostly cloudy across much of the region on Wednesday, but then more sunshine is expected from Thursday to Sunday.

Temperatures will warm up progressively throughout the next 5 days as high pressure builds over the area, and by Saturday-Sunday, low-elevation areas and interior valleys away from the coast will be getting hot.

NORTHERN ROCKIES

Wed – On the backside of a low pressure trough, a trailing disturbance and cold front will bring another round of rain and snow showers. Snow levels will be quite low for this time of year, dipping to 6,000 to 8,000 feet in some areas.

Most areas will see only light snow amounts, but one exception is the Beartooth Range in Southern Montana where areas above 10,000 feet will pick up 2-6 inches.

Thu – A drying trend is expected with increasing sunshine and warmer temperatures, though it will still be cooler than average for mid-June. The Glacier NP area will see lingering clouds early with decreasing clouds in the PM.

Fri – Another disturbance and cold front will slide in from the northwest, bringing showers to Northwest Montana and Glacier during the day, and to Southern Montana and Northern Wyoming (Gallatin, Beartooth, Bighorns) on Friday night. 

Thunderstorms are also possible across NW Montana, though it's a modest risk with StormNet currently projecting 10-25% lightning probabilities.

Sat-Sun – Most of Montana will see a drying trend this weekend, while areas along and east of the Divide in Wyoming and Southern Montana (Beartooths mainly) will see a chance of showers both days. Temperatures will be on the chilly side so lightning potential looks minimal.

Instead, we're looking at high-elevation snow this weekend, including the potential for heavy snow in the Beartooths and Bighorns above 9,000 feet.

For Mistymoon Lake in the Bighorns (below Cloud Peak), at an elevation just over 10,000 feet, individual weather model projections in our forecast blend are generally projecting 5-15 inches of snow over the next 5 days.

Areas west of the Divide will see a drying trend this weekend along with warmer temperatures. Overall, a beautiful weekend is expected for outdoor adventures.

BC INTERIOR & CANADIAN ROCKIES

Wed – Cool and damp conditions will prevail with scattered showers favoring the Alberta Rockies along and east of the Divide, and especially in Southern Alberta. Thunderstorm chances will largely be confined to the prairies east of the Rockies. Snow levels will range from 7,000 to 8,000 feet.

Thu-Fri – During the morning, a brief weather window is expected, then another disturbance will arrive from the northwest with showers and thunderstorms developing in the afternoon and continuing into Friday. On Friday, the focus of showers/storms will shift into Southeast BC and Southern Alberta (Fernie to Waterton Lakes favored). Snow levels will range from 7,000 to 8,000 feet.

Sat-Sun – A beautiful weekend awaits as high pressure builds in from the west, leading to warmer and drier conditions along with increased sunshine. 

Monday (June 15) to Friday (June 19):

Early next week (June 15-16), a ridge will remain over the West Coast, leading to warm/hot and dry conditions across the westernmost states with more seasonal temperatures across the Rockies.

However, mid to late next week (June 17-19), the ridge will break down, and a trough will take hold over the Northwest and West Central U.S. A transition to below-average temperatures is also expected for much of the West as a cold front moves through. 

Despite the cool-down and "troughy" look, moisture looks fairly limited overall next week. The North Cascades and Northern Rockies, along with Western Canada, will likely see an increase in shower chances mid to late week (~June 17-19), and the Central Rockies (WY and CO, especially east of the Divide) could see an uptick in thunderstorm chances late in the week (~June 18-19).

Early in the week (~June 15-17), lingering subtropical moisture will keep afternoon thunderstorm chances going over the Southwest, mainly in AZ and NM and perhaps in the High Sierra. But the potential for meaningful rain looks limited as low-level moisture will be limited, and fire danger will remain high due to dry thunderstorm potential. 

Thanks so much for reading! Next update on Friday.

Alan Smith