The western U.S. has been dealing with extreme heat all summer, and this week has been no exception. Some parts of the west, such as Oregon and California, saw temperatures this past weekend that challenged record all time highs. While relief from the unbearable heat may be welcomed, the moisture that's coming brings a whole new risk of its own.
Heat Wave Finally Letting Up
Good news awaits for the residents of the western U.S. as the heat dome is finally beginning to break down. Cool air coming in from the Pacific is causing the record breaking temperatures to dip slightly, and several areas closer to the coast will see temperatures 15-25 degrees lower this weekend compared to earlier in the week.
A heat-stricken Oregon will see temperatures closer to the low to mid 80's, and Seattle will see mid-70's by the weekend.
The interior Northwest may not see as much of a dip in temperatures as the coast will, however they still will see lower temperatures closer to high 80's by the weekend.
The Northwest isn't the only area feeling the cooler air as the Southwest will also dip lower. Areas such as Palm Springs, California will only reach to the high 90's, compared to the highs in the 110 range. Las Vegas will also feel lower temperatures in the 80's by next week.
Risk of Flooding Replaces Relentless Heat
While residents may be enjoying the more bearable heat to close out August, they'll have a new threat to keep their eyes on. The flow of air around the heat dome mixed with the high pressure in the central Plains will produce southerly winds in the West.
As this pattern continues, the Southwest is likely to see heavy downpours and thunderstorms develop. Saturday and Sunday are expected to bring flooding rainfall across Southern California, Western Arizona, and Las Vegas.
Tropical Development This Week
Forecasters are monitoring a potential area of tropical development in the east Pacific this week. If it continues to develop into a tropical storm, the next name on the list is Hilary.
Heavy rainfall is still expected to hit the Southwest even if the tropical storm doesn't make direct landfall. The Las Vegas area could get hit with 1-2 inches of rain just this week, where they typically average 0.32 inches of rain in the entire month of August. Some areas may even see double the amount of rain, which could likely lead to life-threatening flash flooding.
Residents of Phoenix and Flagstaff, Arizona, along with Los Angeles and San Diego should be prepared for flash flooding and be aware of rushing water or ponding.
While the Southwest is the main target, the moisture may not only be limited to this area. The Northwest should also be prepared for the risk of flash flooding.
The moisture is good news for the drought and wildfires as the rainfall could help limit the spread, however other areas that don't see rain and only see lightning could be at a higher risk of lightning strikes which could ignite fires.