WEATHERAmerica Newsletter; Saturday, June 27, 2026; EXTENDED PERIOD FORECAST

[Larry Cosgrove]

EXTENDED PERIOD FORECAST

(Between Day 11 And Day 15)

 

Gradual Flip To A Hot West, Central Vs. Mild/Cool East Alignment

CIMSS (3)

CMA

TropicalTidbits.Com (Dr. Levi Cowan) (3)

NOAA/PMEL

NOAA/CPC

IRI/Columbia University

HPRCC/University Of Nebraska (2)

Environment Canada

WeatherBELL (8)

NOAA/CPC

I admit that with all of the superlatives being thrown out at the general public concerning weather (HEAT DOME HIGH! SUPER EL NINO! ARCTIC MELTDOWN! among others) it is easy to lose track with the actual and expected outcome of atmospheric conditions around the world. Especially in the USA, where some broadcast and social media outlets are losing it. Like the recent Japanese and Venezuelan earthquakes being CAUSED BY GLOBAL WARMING. Even if that is definitely not true, you know it will jazz numbers on some enthusiast or ratings-starved station or network. Trouble is we will have a tough period of conditions coming up where we must toss aside the hype and pay attention to timelines and intensity of weather systems.

An example of this is the infamous cries of "summer cancel" at the start of the month blamed on your El Nino. Which has now escalated to moderate but will never be a true "super" since some northern Pacific waters are cool and the equatorial Atlantic Basin/MDR is almost entirely below seasonal averages. A truly exceptional +ENSO signature, similar to the late summer of 2015, was essentially wall-to-wall warm. We are likely going to touch on or exceed the "strong" benchmark average at sector 3.4, but many of the prediction schemes suggest a collapse of the warming around New Year's Day 2027. The point of all this is simple: we need to monitor the 500MB ridge/trough scenario (+PNA/-AO expected) and excessive heat displays. Climatology for stronger 0 deg Pacific Basin warm waters is usually skewed hot from California to Texas, occasionally reaching the Pacific Northwest. The chief analogs for RONI are 1976, 2023 and 2025, so the worst of the summer heat should be along and west of the Mississippi River.

It looks like the current build-up of very hot weather (597dcm or higher ridge core at 500MB by next weekend), will start to retrogress in the second week of July. An East Coast weakness and occasional shortwave injection shows up on many of the ensemble platforms, which would leave the hottest values over the West and Central parts of Canada and the lower 48 states. There may be a "bleed-through" injection of hot air into the Mid-Atlantic and New England in the fourth week of July, with thunderstorms an ongoing threat with cold fronts from the Great Lakes into the Carolinas. But I see the JAS time frame as being a risk to power overuse in CAISO, SPP, ERCOT and some MISO districts, not so much the NYMEX, PJM and SEISO domains. Monsoonal moisture in Mexico may occasionally get into the Desert and Intermountain Regions, but will likely not have high impacts with the subtropical high (Sonoran) in the way.

Southern branch moisture and storms will be a factor with cooling through the southern third of the nation starting at the end of September. I suspect that the first half of winter will be that oft-abused "typical El Nino" mild/dry North/Central vs. cool/wet South alignment. But give it time, that could change.

 

Prepared by Meteorologist LARRY COSGROVE on 
Saturday, June 27, 2026 at 11:20 P.M. MT

Disclaimer: 
The previous statements are my opinions only, and should not be construed as definitive fact. Links provided on this newsletter are not affiliated with WEATHERAmerica and the publisher is not responsible for content posted or associated with those sites.

Copyright 2026 by Larry Cosgrove

All rights reserved.
This publication may not be reproduced or redistributed in whole or in part without the expressed written consent of the author.