My Favorite Summer Weather Map Layers:

• StormNet Lightning Risk
• Current Lightning Strikes and 1-Hour Risk
• Current Radar
• Forecast Radar
• Forecast Total Precipitation
• Current Air Quality
• Smoke Surface Forecast (ground level)
• Smoke Sky Forecast (average smoke ground level to upper atmosphere)
• Forecast Air Quality (low-res 3-5 day smoke outlook)

5-Day Big Picture Overview:

A strong ridge of high pressure will build over the Interior West, with a significant heatwave expected across the Northern Rockies. A weak monsoonal flow will also be in place over the Southern Rockies and Southwest.

A trough-dominant pattern over the Northwest will keep a cooler airmass in place across BC and Western Washington, with Pacific disturbances also bringing showers to the BC Coast Range.

COLORADO

Wed – An active day of thunderstorms is expected statewide, with storms possibly beginning prior to noon over the high country. Activity will become more widespread by early afternoon, and this includes the I-25 urban corridor.

Stronger storms will be capable of producing locally heavy rain east of the Divide, where better moisture will be in place. West of the Divide, rainfall looks to be lighter as drier air will be pushing its way in from the west as the day progresses.

The primary threat of large hail has also shifted further east into the northeast plains, with only a very small chance of large hail across the Denver Metro area and I-25 corridor.

Wildfire smoke should be less widespread on Tuesday compared to recent days, at least across Northern Colorado. Locally heavy smoke can still be expected downwind of larger fires in Southern and Central Colorado.

Thu – This is trending toward another active day of thunderstorms statewide. West of the Divide, moisture levels will be minimal with most storms producing light rain, though stronger storms could produce locally heavy downpours. Also, as a shortwave trough approaches, there is a chance of pre-noon thunderstorms.

East of the Divide, moisture levels will be greater, and wind shear will increase as the shortwave moves through, resulting in more numerous thunderstorms. Stronger storms will be capable of producing locally heavy rain, severe wind gusts (58+ mph), and large hail of 1" or more in diameter.

Fri – The setup looks similar to Thursday with enough lingering moisture for a chance of thunderstorms statewide.

Areas east of the Divide will have access to better moisture and will likely see more numerous thunderstorms and better potential for meaningful rains, while areas west of the Divide will see more isolated activity with storms producing lighter rain. 

Sat-Sun – Hotter and drier conditions can be expected across most of the state. North to northwest winds aloft will likely keep the worst of the wildfire smoke confined to Southern Colorado, barring any new fire starts of course.

The only exceptions to the dry forecast will be a chance of isolated afternoon thunderstorms along the Continental Divide on Saturday, while a relative uptick across the San Juans is possible on Sunday as the leading edge of monsoonal moisture arrives. 

UTAH

Wed – A shortwave will track across Utah, resulting in isolated to scattered thunderstorms across the Uintas, Wasatch, and SLC Metro. Most storms will only produce light rain and gusty winds, but stronger storms could produce locally heavy rain across the higher elevations.

Isolated thunderstorms are also possible around Moab and the La Sals, but these storms will only produce light rain and gusty outflow winds.

Thu – Another shortwave will move across Utah, resulting in isolated to scattered thunderstorm chances across most of the state, excluding the southwest. The lower levels of the atmosphere will be even drier compared to Wednesday, so this is a dry thunderstorm setup in which storms will produce strong outflow wind gusts and little rain. Fire danger will be greater as a result. 

Fri – Most of the state will see a thunderstorm-free day, but lingering mid-level moisture will result in a chance of isolated storms across Eastern Utah, mainly from the Uintas southward to Capitol Reef, Canyonlands, and the La Sals. Once again, any storms will produce light/spotty rain and gusty winds, which will keep the fire danger elevated.

Sat – Hot and dry conditions can be expected statewide. SLC and lower elevations of Northern Utah are expected to see highs well into the 100s.

Sun – Hot and dry conditions will prevail across Northern Utah, while the leading edge of monsoonal moisture looks to sneak into Southern Utah. This will result in a chance of isolated and mainly dry thunderstorms, but will be a precursor to a more active pattern expected next week with more significant moisture possible.

SOUTHWEST

Wed – Scattered afternoon thunderstorms can be expected across New Mexico and Eastern Arizona, to about as far west as Flagstaff. Storms will be capable of producing locally heavy rain across the higher elevations, while the lower elevations will see more of a dry thunderstorm setup with light rain and gusty outflow winds.

Winds aloft will also shift to NW (blowing from the NW). As a result, smoke from the Pocket Fire will likely be heavier in Sedona compared to Flagstaff in the days to follow.

Thu-Sat – Moisture will decrease over Arizona and remain somewhat higher across New Mexico. As a result, daily rounds of scattered thunderstorms will continue to favor Central and Southern New Mexico as well as Southeast Arizona, with more isolated activity in Northern New Mexico.

Sun – A transition in the pattern will occur with decreasing moisture across New Mexico and increasing moisture across Arizona as deeper monsoonal moisture begins to push in from the south. This will be the start of a more sustained monsoonal flow for Arizona, and storms on Sunday will be capable of producing locally heavy rain.

Winds aloft will also shift to easterly, which may push the worst of the smoke from the Pocket Fire away from both Flagstaff and Sedona, though smoke could still settle into these areas overnight.

CALIFORNIA/SIERRA

Wed-Sat – A quiet weather pattern can be expected with dry conditions and warm to hot temperatures, as high pressure builds in from the south and east.

Sun – The leading edge of monsoonal moisture will arrive, but confidence in afternoon thunderstorm potential for Sunday is low.

Our StormNet Model, for instance, does not have any lightning probabilities for Sunday at this time and holds off any threats until next week.

At the very least, an increase in cloud cover is likely on Sunday, which may just end up being flat, overcast skies initially. This could act as a stable layer that prevents surface heating needed for thunderstorms to develop, but again, confidence is low.

PACIFIC NORTHWEST

Wed – A cold front (marine air push) will arrive west of the Cascade Crest, leading to cooler temperatures, while above-average warmth will prevail east of the Cascade Crest. Low-level clouds can also be expected across the Western PNW and light sprinkles couldn't be ruled out.

Thu – Temperatures will rebound a bit, and more sunshine is also expected throughout the region.

Fri – Another cold front will arrive, leading to increased low-level cloud cover and below-average temperatures west of the Cascade Crest, while areas east of the Crest will be comparatively cooler than Thursday but still warmer than average.

Light showers/sprinkles are possible across the Cascades, Olympics, West Coast, and BC Coast Range, but significant rain is not expected.

Sat-Sun – The airmass will remain divided with below-average temperatures west of the Cascade Crest and above-average temperatures east of the Cascade Crest.

Sunshine may be more abundant west of the Cascades compared to Friday, but showers are possible across the Northern WA Cascades and more notably across the BC Coast Range on Saturday as a stronger Pacific shortwave moves through.

NORTHERN ROCKIES

Wed – A shortwave trough moving through will trigger isolated to scattered thunderstorms across most of the region. Pockets of higher coverage are projected across the Sawtooths, Southern Bitterroots, Beartooths, and Bighorns.

Low-level moisture will be lacking in this pattern, so most storms are only going to produce light rain and gusty winds, but stronger storms in the Beartooths and Bighorns could produce locally heavy rain.

Thu – Thunderstorm chances will favor areas east of the Divide in Wyoming and Southern Montana (Beartooths, Bighorns, Winds, Snowys), with only some isolated activity just west of the Divide. Most storms will only produce light rain and gusty winds, but stronger storms east of the Divide could produce locally heavy rain.

Fri-Sun – A heatwave will take hold as high pressure builds over the region, resulting in hot and mostly dry conditions. We could see some isolated thunderstorms east of the Divide in Wyoming and Southern Montana on Friday, while thunderstorm chances look minimal on Saturday and Sunday.

BC INTERIOR & CANADIAN ROCKIES

Wed – Mostly dry conditions will prevail other than some isolated thunderstorms across Southeast BC and Southwest Alberta (Fernie to Waterton Lakes).

However, smoke from the Brunswick Creek Fire west of Merritt is projected to impact much of the region, especially along the Trans-Canada Highway corridor from Revelstoke to Golden to Banff. Southern and eastern areas such as Fernie and Waterton Lakes should avoid the smoke for now.

Thu – Mostly dry conditions are expected, other than possibly some isolated thunderstorms over the Alberta foothills. However, a brief shift from SW to more W winds will likely transport some smoke into Southeast BC and Southwest Alberta, including Fernie and Waterton Lakes.

Fri – Dry conditions are expected during the day, but light showers are possible around Revelstoke, Golden, and Banff overnight as a trough approaches. These areas will also be more likely to experience smoke during the day on Friday as winds aloft shift back to WSW.

Sat – More numerous showers and thunderstorms are expected from Revelstoke to Banff, with drier conditions further south toward the U.S. border. Smoke will be highly dependent upon fire behavior in the days prior, but if the fire remains active, then smoky conditions may prevail near the Trans-Canada Highway corridor.

Sun – A drying trend is expected, aside from possibly some lingering early morning showers along and north of the Trans-Canada Highway.

Outlook for Monday (July 13) to Friday (July 17):

Here comes the monsoon!

Medium-range models remain in good agreement with a strong monsoon push into the Western U.S. next week, leading to an uptick in thunderstorm activity along with a growing potential for meaningful rain across the West Central U.S.

Initially, this looks to be a westerly focused monsoon with moisture surging out of the Gulf of California. This would favor Arizona, Utah, Nevada, Eastern Idaho, and Western Wyoming, and to some extent the higher terrain in California.

Here is a look at projected precipitable water anomalies by the middle of next week (a measure of water vapor in the atmosphere).

The biggest question mark right now is how this monsoon surge will impact Colorado and New Mexico.

The deepest moisture is projected to track west of these areas at least initially, but moisture could ramp up west of the Divide in Colorado as the week progresses. However, there are some model discrepancies in how far east the deeper moisture will push, so we'll need to keep an eye on this as we get closer.

Thanks so much for reading! Next update on Friday.

Alan Smith