The first month of meteorological fall is here. September looks to run above average across most of the U.S., according to a just-released outlook by Atmospheric G2 and The Weather Company. The Pacific Northwest is the one region bucking the trend, with cooler-than-normal temperatures expected.

Key temperature takeaways

• Hottest through the middle of the country. The strongest above-average signal runs in a corridor from North Dakota south through the Plains and into Texas.
• Warm from the Gulf Coast to the Great Lakes. Above-average temperatures also cover the Rockies and the mid-Atlantic.
• Only slightly warmer than average in the Southwest and Northeast. These areas still trend above normal, but the departure is modest compared with the Plains.
• Coolest in the Pacific Northwest. This region has the best chance for sweater weather, with below-normal temperatures offering some relief after a difficult stretch of fire weather.

September's precipitation outlook

• Wettest in the Four Corners. The Southwest sees the highest totals relative to normal, with the North American monsoon still active in its final weeks before the season winds down in late September.
• Wetter through the interior West and Plains. Above-normal precipitation extends from the northern Rockies and Great Basin east through the Plains and into parts of the Midwest.
• Drier along the Pacific Northwest coast. Despite cooler temperatures, the Northwest stays on the dry side of the map — which tempers the fire-season relief a cooler month would otherwise bring.
• Drier in the East and Southeast. The Great Lakes, upstate New York and much of the Northeast trend below normal, along with Florida and parts of the Gulf Coast.

A historically strong El Niño is emerging rapidly, according to Todd Crawford, Vice President of Meteorology at Atmospheric G2 and chief author of the outlook. The current event is clearly outpacing all other events at this point in their development, including the 1997 and 2015 El Niños.