As summer winds down, Ponder on Weather has an eye toward what fall and winter may hold as we shift toward crisper temperatures across much of the U.S. driven by building La Niña conditions. This transition promises cooler air intrusions, especially in the central and eastern regions, setting the stage for an chilly fall and the possibility of skiers and snowboarders hitting the slopes early.
La Niña is emerging in the equatorial Pacific, with sea surface temperatures dipping below average. This setup, expected to peak by October, will favor a more active polar jet stream, ushering in northwest flow and periodic cold pushes from the north. While the Pacific Northwest may linger on the warmer side, the rest of the country braces for below average temps starting late August into September.
Regional Crisp Temperature Breakdown
- Western U.S.: The Pacific Northwest and Desert Southwest could see above average warmth persisting, but expect occasional cooler dips as La Niña strengthens. Drought conditions here may intensify without significant rain.
- Central U.S.: Areas like the Southern Plains and Four Corners will experience crisp, below average temperatures, with wetter spells in Texas and Oklahoma easing drought pockets.
- Eastern U.S.: The Ohio Valley, Mid-Atlantic, and Northeast are poised for cooler than normal conditions, including rainy spells that could transition to early snow teases by November.
Severe Weather and Early Chill Risks
With the Madden-Julian Oscillation ramping up post-Labor Day, upward motion could spark more active weather, including severe storms in the Plains and Ohio Valley. However, the focus remains on those crisp air masses. Arctic Oscillation trending negative will press cold domes southward, making October and November feel brisk.
Early Winter Teasers and Snow Potential
By December, a weaker subtropical jet may dry out the South, but the North could see wetter, colder setups. The channel highlights a possible return to ENSO neutral by winter’s second half, amplifying polar jet activity for deeper cold intrusions, hinting at snowy surprises in the Ohio Valley and Northeast.
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