Following what has been a record-setting summer in many cities in the Southwest, the heat has continued into the first full month of autumn. However, a pattern change may finally signal a turn to more fall-like weather.
Unfortunately, significant cooling is unlikely to be felt until next week in most locations.
As has been the case so many times over the past few months in the Southwest, record highs were set again on Wednesday.
Not only were daily records set, but Phoenix recorded its 144th day at or above 100 degrees. This surpassed the record of 143 such days in 1989. Before this latest record fell, the city had already set records for the most 110-degree days and 115-degree days in a given year.
Temperatures well above normal have not been confined to only desert locations either. Los Angeles has had an exceptionally warm October so far.
"Downtown Los Angeles is running almost 7 degrees above normal thus far through the month of October," said AccuWeather Senior Meteorologist Dan Pydynowski.
Many areas farther north into the Sacramento and San Joaquin valleys of California are running about 5 to 6 degrees above normal so far this month.
Since no rain has fallen, all of the sun's energy goes into heating the ground. When the ground is moist, the sun must first work to evaporate the moisture. Therefore, the tinder dry conditions have further added to the unusually high temperatures and continued to keep the fire danger very high.
Through the end of the week and into at least the beginning of the weekend, the excessive heat is likely to persist. By Sunday, cities in coastal California will get some relief as an onshore flow from the cool Pacific Ocean takes hold.
"After dealing with several days of near-record heat around Los Angeles, high temperatures will finally be trimmed starting Sunday and continuing into much of the following week," Pydynowski said.
Farther inland, away from the modifying effect of the wind off the ocean, the cooling will be delayed and muted.
"Across the interior of the Southwest, there will be little escape from the heat. Cities such as Las Vegas and Phoenix will continue to experience near-record heat through at least Sunday, with temperatures very stubborn and reluctant to come down at all heading into next Monday and Tuesday," Pydynowski added.
As high pressure retreats westward into the Pacific Ocean and weakens, this will allow temperatures to finally be somewhat lower even inland locations.
That said, while the record-breaking heat is likely to end, temperatures are still likely to be above normal across the area. Some of the typically hottest locations, such as Palm Springs, California, may still exceed 100 F through Tuesday.
There are some signs that more substantial cooling may take place later next week, but that is far from a certainty at this point.