WEATHERAmerica Newsletter, Saturday, June 20, 2026; SHORT And MEDIUM RANGE OUTLOOKS

[Larry Cosgrove]

SHORT RANGE OUTLOOK

(Through The Next 72 Hours)

 

Either Strong Thunderstorms Or Extreme Heat, Take Your Pick!

METEOBLUE

University Of Wisconsin (3)

PivotalWeather.Com (3)

ECMWF

College Of DuPage Weather Laboratory

It is interesting to see that I have read a few entries online stating that this severe weather season has been a bust. Which, viewed and translated by experienced convective forecasts can be translated to, "I was out of position and didn't wake up on time to see the tornadoes that kept hitting the stretch from the central/northern Great Plains through the Corn Belt". Seriously, this has been a banner year so far with Illinois getting routinely hit by tornadic thunderstorms, while other locales from Texas to Minnesita and Ohio/Kentucky have been ripped by strong winds and flooding rains. The problem is, we still have about nine days to go before we are out of the maximum tornado and thunder threat, and there are no signs of the pattern slowing down.

The vertical velocity and rainfall accumulation total charts give you a good idea of the danger zones for severe weather strikes, all the way from Alberta through the High Plains to North Texas, then across the Heartland into the Ohio/Tennessee Valleys, the Mid-Atlantic and New England between now and Wednesday.See also the dry look from the Pacific Northwest, Desert/Intermountain Regions into Texas and Louisiana, where mid-level drying brings a thick cap but also brutal heat and surface humidity without much likelihood for cooling afternoon convection.

 

MEDIUM RANGE OUTLOOK

(Four To Ten Days From Now)

 

Extreme Heat Across Western/Central USA As We Exit June

METEOBLUE

ECMWF (4)

TrueWx.Com (4)

College Of DuPage Weather Laboratory

In summer cases where it is generally cool across Canada and hot over the southern half of the USA, odds are the locations in between the regimes will have its fair share of thunderstorms. Now while I doubt that the 500MB storms moving out of the Gulf of Alaska remain as strong as it appears to be now, enough energy and cold instability will be present for multiple cases of severe weather between Interstate 70 and the Canadian border. This set-up could continue up until the Independence Day weekend, but there may be a shift northward where only those states adjacent to the international boundary will be prone to intense convection. The eventual path of the second storm in this sequence will likely be from British Columbia to Quebec, which in theory might enable some of the thunderstorms to target the Ontario Peninsula and St. Lawrence Valley.

Notice also that many of the forecast schemes develop a large Great Smokes type heat ridge on June 30 - July 1, so a wide swath from california into the Midwest and Appalachia could see extreme heat and humidity.