Following a mild June, the weather pattern turned hot and dry across the West during July and the North American Monsoon did not get going until late in the month.

August is shaping up to be a cooler and wetter month across the Central and Northern Rockies, while the hotter and drier than average conditions are expected to prevail across the Southwest.

July 2023 Review:

Monsoon season began later than usual this year, and even when it did start to take hold late in the month, rainfall was underwhelming across the Southwest. Some areas in Arizona, New Mexico, Southern Utah, and Southwest Colorado experienced one of their driest Julys on record.

Areas east of the Continental Divide in Wyoming and Montana received near to above-average rainfall in July.

Also, above-average anomalies are showing up across Coastal California, but this should be taken with a grain of salt. Most locations near the coast of California average very little rain during July, so even if only a little bit of rain falls, it can make it an "above average" month. 

July was also a very hot month across much of the West. In fact, many areas in the Southwest experienced their hottest July on record – and some areas experienced their hottest month (of any month) on record.

Similar to the rainfall trend, areas near and east of the Divide in Southern Montana, Wyoming, and Colorado experienced near-average temperatures with shorter and less frequent heat waves. 

August 2023 Outlook:

August is starting out with a significant push of monsoonal moisture into the Central and Northern Rockies. Moisture is going to hang around these areas through the first week or so of August, resulting in wetter-than-average conditions for parts of Idaho, Wyoming, Montana, Northern Colorado, and Northern Utah.

This is setting up to be a "displaced monsoon moisture" scenario, as drier air will be working its way back into the Southwest where monsoon moisture usually resides.

A strong jet stream setting up over the Central Rockies through the second week of the month will keep deeper monsoonal moisture suppressed south of the Mexico border while the Northwest and Northern Rockies will see more unsettled weather with frequent disturbances and lingering moisture.

This pattern may eventually relent during the second half of the month, and monsoon moisture will eventually try to sneak back into the Southwest – but it remains to be seen how strong (and for how long) of a moisture push we may see by then.

Overall, the pattern through the first half of August has tipped the odds in favor of above-average monthly rainfall for the Northern and Central Rockies, and below-average rainfall for Arizona and New Mexico.

Temperatures are expected to follow a similar trend this month with near to below-average temperatures expected across the Central and Northern Rockies and above-average temperatures across the Southwest.

Also, high pressure is expected to build over the Pacific Northwest heading into mid-month, which will support above-average temperatures there as well. Weaker areas of low pressure undercutting the ridge may temper the potential for heat waves (at least somewhat) across California. 

Fire and Smoke Outlook:

At a larger scale, this has been a fairly tame summer for wildfires across the Western U.S. so far. Western Canada has experienced a more severe fire season, though there has been some improvement there in recent weeks.

As of early August, a handful of large fires are burning across Oregon, Idaho, and Montana, which are resulting in locally heavy smoke and localized air quality concerns. Most areas in the West have not been experiencing significant smoke issues, however. 

There is potential for wildfire activity to increase across the Northwest during the month of August. The Northwest will be on the outer periphery of monsoonal moisture during the first 1-2 weeks of the month, which could result in a mix of wet and dry thunderstorms with the potential for lightning-triggered fires.

Also, there is growing potential for heat to build over portions of the Northwest heading into mid-month, which would also lead to increased fire danger.

Further south, below-average potential for significant fires is still being forecast across the Sierra Nevada Range in California thanks to record snowpack and a wet spring as conditions have not dried out significantly yet. 

Wildfire potential is expected to increase across Arizona and New Mexico, however, thanks to an underwhelming monsoon season. 

Across Western Canada, above-average wildfire potential is expected across a large portion of BC and Northern Alberta, though the coverage areas of "above average" and "well-above average" fire potential have decreased compared to last month's forecast. Fire potential is expected to be "average" across the Southern Canadian Rockies.

Alan Smith, Meteorologist