Strengthening high pressure will result in hot temperatures over the next several days across the west, especially across the Great Basin from California to Utah. The heat will extend into the Inland Northwest at times as well.

Hot and dry conditions combined with a series of disturbances moving across the Northwest will not help with the ongoing fires across the region, and will also lead to an elevated threat of new fires starting.

Forecast Smoke (surface)

Forecast Smoke (sky)

Most areas in the West will also see a drying trend over the second half of this week as the core of the monsoon shifts farther south toward the Mexican border.

New Mexico and mountainous portions of Eastern Arizona will see the most widespread thunderstorms and best chances of wetting rains over the next 5 days, but rainfall will be less compared to recent days and the flash flooding risk will decrease as a result. 

The other area of interest will be the Northern and Central Rockies where a series of weak disturbances will interact with remnant monsoonal moisture to result in occasional thunderstorms. 

Thunderstorms in the Central/Northern Rockies will have less moisture to work with overall and will not produce as much rain. The farther north you go into Wyoming/Montana/Idaho, there will also be a risk of dry thunderstorms and lightning-triggered wildfires. 

Forecast for Wednesday, July 7th

The hottest temperatures relative to average will extend from Utah north into Montana, with more comfortable temperatures along the West Coast as well as Southeast Colorado/Eastern New Mexico. 

A weak disturbance moving across the Northwest and Northern Rockies will result in scattered dry thunderstorms across Central Idaho, Southwest Montana, and Northern Wyoming. Strong winds will be possible with storms in these areas. The North Cascades in Washington could actually see a few thunderstorms on Wednesday as well. 

Farther south, the higher elevations in Colorado will see more isolated and weaker thunderstorms compared to recent days, with the a better chance of thunderstorms and wetting rains expected in Southern New Mexico and Southeast Arizona.

Forecast for Thursday, July 8th

A cold front moving across the Inland Northwest and Northern Rockies will offer some respite to the heat, but not much as temperatures will still remain above average. The rest of the West will generally be warmer than average as well, except for some coastal areas in the Pacific Northwest.

Isolated dry thunderstorms with little rainfall can be expected across most areas of the Rockies on Thursday. Even New Mexico will see a relative break in the action with less thunderstorm coverage.

Forecast for Friday, July 9th

Portions of Montana and Wyoming will see cooler temperatures behind an early morning cold front, while the western states will see temperatures heat up to well-above-average values. The southwest and Four Corners region will also continue to trend hotter as the influence of the monsoon lessens compared to the past week.

A cold front sliding across the Northern Rockies and then pushing south along/east of the Divide will lead to an uptick in thunderstorm coverage across Montana, Wyoming, and Colorado. Most storms will produce light to moderate rain, but lightning will be more of a threat for hikers and climbers compared to Wednesday and Thursday. Arizona and New Mexico will see another relatively quiet day with only isolated thunderstorms.

Forecast for Saturday, July 10th

High pressure and hot temperatures will continue to expand across the Far West and Great Basin, while areas east of the Divide in Wyoming and Colorado will see a cool-down.

Areas along and east of the Divide in New Mexico, Colorado, and to a lesser extent Wyoming, will see the best chance of thunderstorms on Saturday afternoon with much drier conditions west of the Divide.

Forecast for Sunday, July 11th

Another hot day is in store for areas west of the Divide, while Eastern Colorado and Eastern New Mexico will see temperatures running below average.

Moisture associated with the monsoon will increase across the far southwest with thunderstorm coverage picking back up across New Mexico and Arizona, and extending west into the Sierras as well.

Outlook for Mon, July 12 - Fri, July 16

The heatwave will start to relax next week, but temperatures will still remain warmer than average across much of the West. A trough of low pressure is projected to set up off the Northwest Coast late next week, which will lead to a cooling trend for Coastal Washington and Oregon as onshore flow increases.

Monsoonal moisture will remain confined to the far southwest with Arizona and New Mexico expected to see the most widespread thunderstorms along with wetting rains, while thunderstorm coverage will become more isolated the farther north you go.

Looking farther out, I'm still seeing signs that monsoonal moisture will eventually start to work its way north again during the second half of July, which would lead to increasing thunderstorm potential across Colorado, Utah, and to some extent the Northern Rockies.

Thanks for reading! Next update on Friday (7/9).

ALAN SMITH

NEW: Proprietary Weather Forecast Data

Our goal is to create the most accurate weather forecast, period. 

On July 1, 2021, we began updating the forecasts on OpenSummit with a proprietary blend of global data from the GFS (American), GDPS (Canadian), and ICON (German) weather models, along with high-resolution data from the HRRR (American) and HRDPS (Canadian) weather models.

Previously, we used data from the National Weather Service (NOAA). While the NOAA data is great for cities and lowland environments, it limited our ability to adjust the data to create the best possible forecast for complex mountain environments with large changes in elevation.

Why is this new forecast data better than the old forecast data? The benefits include:

• Proprietary algorithm to improve the precipitation, lightning, temperature, and wind speed calculations for mountain environments.
• Provides the ability to create a forecast for any location (and elevation) to ensure that we are forecasting conditions on the mountain and not for a nearby town.
• Blending multiple global and high-resolution models increases accuracy and confidence in the forecast.

The data can be viewed as hourly forecasts for the next 5 days and includes:

• Daily High & Low Temperature
• Hourly Chance of Precipitation
• Hourly Lightning Potential
• Hourly Temperature
• Hourly Wind Speed, Gust, & Direction
• Hourly Cloud Cover %

This new blend of proprietary forecast data is updated every hour on OpenSummit for thousands of locations across the United States and we are adding new locations every day.

Here is an example of the OpenSummit 5-day hourly lightning potential forecast for Longs Peak, Colorado in Rocky Mountain National Park:

Use the links below to view the 5-day hourly weather forecast for popular locations across the United States:

Denali, Alaska

Grand Canyon, Arizona

Half Dome, California

Mt. Rose, Nevada

Mt. Rainer, Washington

Pikes Peak, Colorado

Fruita, Colorado

Grand Teton, Wyoming

Mt. Superior, Utah

Moab, Utah

Lone Mountain, Montana

McGown Peak, Idaho

Mt. Hood, Oregon

Mt. Washington, New Hampshire

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Explore Locations → OpenSummit.com

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