I hesitated to use the term "Dog Days" in this forecast, even though the weather pattern pretty much fits the bill for a typical last half of summer. But "it is what it is" (another very worn adage), and be forewarned of monotony that often accompanies an established El Nino signature with the western two-thirds of the USA. When a Sonoran heat ridge is overwhelmingly dominant, dryness and heat are the keywords. In examples like 1976 and 2012, shortwaves in the Gulf of Alaska are shunted into central Canada before careening south-eastward into the Great Lakes and the Northeast. The Bermuda High is much less of a factor, so areas along and to the right of the Appalachian Mountains trend cooler after the first week of July. This is the scenario that will likely continue through the third week of September. At that point in time, changes occur in California with a developing southern branch that will bring more rain, and cooler temperatures, too much of the nation for the autumn period.
Now you may ask, "how could this forecast screw up"? One concern is the tropics. With an entrenched El Nino that likely will not start breaking down until after New Year's Day 2027, we could get a lot less from the tropics and temperatures might be warmer at times along the Eastern Seaboard. Then again, if a warm-core disturbance somehow got into the Gulf of Mexico or grew in the Sargasso Sea and threatened Florida or the Interstate 95 corridor, the resultant 500MB trough could bring polar air further west of the Mississippi Valley. But that challenge might not be until October. For now, draw a box covering the U.S. from the West Coast to the Great Lakes and "Ol' Man River". Inside that delineation for the last week of July through the third week of September will be likely relentless scorching sun, dented ony by a straggler monsoonal fetch over the "Four Corners". The numerical models insist on the worst heat being over California as well as Texas, Oklahoma, and Kansas.
Prepared by Meteorologist LARRY COSGROVE on
Sunday, July 19, 2026 at 1:55A.M. CT
