Now that monsoon season is underway and thunderstorms have become more common over the West during the past week, I wanted to start by posting this neat graphic about backcountry lightning safety published by the National Weather Service in Salt Lake City.

It's a good visual tool of which types of terrain are more vulnerable to lightning danger, while also noting areas that are safer on a scale of 0 to 3 with 0 being the most dangerous. 

Speaking of thunderstorms, moisture associated with the North American Monsoon will result in daily rounds of thunderstorms for much of the West over the holiday weekend and into early next week.

Friday afternoon is shaping up to be another active period for thunderstorms across the Rockies, Southwest, and Great Basin, with a relative decrease in activity across the Sierras compared to prior days.

Thunderstorm coverage will also be lower across Southern Utah on Friday, which is where a center of high pressure is located, resulting in descending air that will help to suppress thunderstorm development.

The recent uptick in moisture has been extremely welcome across the Southwest and Southern Rockies and has at least temporarily reduced wildfire activity and danger.

However, the same cannot be said across the Northwest where fire activity is increasing following the record-setting heatwave over the past week.

A horrible situation has unfolded in the small town of Lytton, British Columbia. This town broke the all-time record high for the nation of Canada three days in a row from Sunday through Tuesday (their new record is 121ºF), only to have a rapidly-spreading wildfire ignite and quickly move through on Wednesday, destroying nearly the entire town and forcing a frantic evacuation. Ugh...

Numerous wildfires have developed across British Columbia this week – a combination of human-caused and lightning-caused. Smoke from these fires will likely begin to impact portions of the North Cascades and Northern Rockies in the coming days.

In addition, several large wildfires have started across Northern California this week, and smoke from these fires is beginning to spread its way into the Interior Western U.S. 

A few wildfires continue to burn in Arizona as well, but could see some relief from heavy rainfall producing thunderstorms due to the recent influx of monsoonal moisture. 

The National Interagency Fire Center has released its latest fire potential forecast for the month of July, indicating above normal fire potential for a large portion of the west – especially the Northwest who has quickly transitioned to dangerously dry conditions due to the recent extreme heat. 

The arrival of the monsoon is expected to bring some relief to fire danger across the Southwest this month, which is good news. 

Forecast for Friday, July 2nd

Well-above average warmth is expected across the Northern Rockies on Friday, while areas east of the Continental Divide in Colorado and New Mexico will see well-below average temperatures.

Thunderstorm coverage will be fairly widespread across most of the Rockies on Friday and wetting rains are expected even up north due to elevated moisture levels. Drier conditions are expected across Southern Utah, while farther west, the Sierras could see some isolated thunderstorms.

The heaviest rains on Friday are expected across New Mexico, Southern Colorado, and Eastern Arizona. In fact, flash flooding will be possible across this region, especially in New Mexico. 

Forecast for Saturday, July 3rd

Above-average warmth is expected across most of the West on Saturday, except for Southern Arizona and New Mexico who will be a little cooler than average due to cloud cover and more widespread rains. 

Thunderstorm coverage should become more isolated across most regions of the West as high pressure strengthens a bit. However, afternoon thunderstorms should still be expected across the higher peaks in the Rockies and Sierras. 

Southern New Mexico and Southeast Arizona will see the highest potential for heavy rains and flash flooding on Saturday.

Forecast for Sunday, July 4th

Temperatures will remain above average for most of the West, though some minor relief is expected across the Inland Northwest and Northern Rockies at least.

Arizona and New Mexico will continue to see the most widespread thunderstorm coverage and heaviest rains and the potential for flash flooding in these areas will remain. Thunderstorms should remain more isolated in Colorado and Utah, but an increase in storm coverage is expected across portions of Idaho, Wyoming, and Montana as a surge of monsoonal moisture lifts northward. 

Forecast for Monday, July 5th

Temperatures will cool off a bit east of the Continental Divide in Montana and Wyoming as a Canadian cold front arrives, but the rest of the West will remain warmer than average.

Monsoonal moisture will increase across the Central Rockies on Monday, resulting in an active day of thunderstorms across Wyoming, Colorado, and New Mexico with wetting rains also expected.

Forecast for Tuesday, July 6th

Cooler air east of the Continental Divide will slide south into Colorado and New Mexico behind a cold front on Tuesday, while areas west of the Divide will remain warmer than average.

Areas along and east of the Continental Divide in Colorado and New Mexico will see the most widespread thunderstorm coverage and heaviest rains on Tuesday, with more isolated storm coverage and lighter rain west of the Divide.

Outlook for Wed, July 7th - Sun, July 11th

The pattern during the second half of next week will feature a strengthening ridge of high pressure, while the monsoon will also relax and become suppressed farther south, leading to a trend toward hotter and drier conditions for much of the West. 

The Intermountain West in particular is likely to return to "heat wave" territory with well-above-average temperatures that could challenge daily (but not all-time) records in some areas. 

Thunderstorms will become more isolated in coverage across the Four Corners region and Central/Southern Rockies with a trend toward dry conditions likely in the Northern Rockies. 

The best chance of wetting rains late next week will be confined to Southern Arizona and Southern New Mexico.

The dry outlook for next weekend should offer a better window for peak baggers compared to this weekend, though hikers/climbers will still need to be on-guard for isolated afternoon thunderstorms. Also, the downside of the return to a hot and dry pattern is that fire danger will increase.

Thanks for reading and Happy Fourth of July! Next update on Monday (7/5).

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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