WEATHERAmerica Newsletter; Saturday, June 27, 2026; SHORT And MEDIUM RANGE OUTLOOK

[Larry Cosgrove]

SHORT RANGE OUTLOOK

(Through The Next 72 Hours)

 

The Pattern Starts To Dry Up, And Heat Up...East Of The Rocky Mountains, That Is....

METEOBLUE

TrueWx.Com (3)

ECMWF

College Of DuPage Weather Laboratory

The cooldown over the Pacific Northwest is impressive, but quite temporary. The deep upper low and cold frontal passage that reaches the northern Rocky Mountains on Monday will serve to create high-altitude snows in ID/MT, and very probably a severe thunderstorm event across the Prairie Provinces and western Ontario during the new week. Warm advection aloft will quickly establish a broad heat ridge that at maturity on Thursday and Friday may stretch from California to New York State.

A plume of Saharan dust in the Caribbean Sea will roll under the big ridge complex and come inland over Texas and Louisiana on Monday, and may last through Wednesday. The dust is not a coolant, but may help to organize diurnal convection along and east of the Mississippi River. If the model guidance is correct, many locations inside the ERCOT, SPP and southern MISO domains will reach or exceed 100 deg F for much of the next 10 days.

 

MEDIUM RANGE OUTLOOK

(Four To Ten Days From Now)

 

I Was Not Joking About The Heat Ridge....

METEOBLUE

ECMWF (4)

PivotalWeather.Com (8)

UQAM (4)

College Of DuPage Weather Laboratory

The temperature forecasts for the eastern 2/3 of the U.S. are uniformly hot, with the Sonoran and Bermudan heat ridges dominating most of the national weather pattern through July 8. As the polar westerlies are pulled to above the Canadian border, the constant procession of intense thunderstorms will shift to the far northern tier and through the Prairie Provinces into Ontario. The soil moisture is already starting to dry out in the middle and lower latitudes of the nation. So the multitude of +95 F readings on those maps should verify.

Diurnal thunderstorms may take shape in the Southeast and Appalachia due to a weakness that develops between the two subtropical highs, which should be completely separated by the time we move into the medium range. A backdoor cold front could drop from Quebec into Virginia and North Carolina, lowering temperatures and relative humidity along the Interstate 95 corridor. Odds are against any prominent tropical cyclone formation on the East Coast. At this time it appears that the Mexican monsoonal moisture fetch will get no further north and west than the lower Rocky Mountains and Texas High Plains.