WEATHERAmerica Newsletter, Saturday, June 22, 2024; SHORT RANGE OUTLOOK

[Larry Cosgrove]

SHORT RANGE OUTLOOK

(Through The Next 72 Hours)

 

Heat Ridge May Separate Into Sonoran And Bermudan Sections (But Hot Weather Continues Southern Two-Thirds Of USA)

METEOBLUE

PivotalWeather.Com (3)

ECMWF

The development of a  weakness in the heat ridge complex affecting the U.S. may permit a frontal passage through the Midwest and Northeast. But there is a price to pay, as rather vigorous energy with a jet stream velocity maximum pushes a storm and frontal structure through those regions today and tomorrow. The very unstable air responsible for the brutal heatwave of the past few days will be pushed out, triggering a severe weather event along and above Interstate 64 and to the right of Interstate 69 on Sunday.

Keep in mind that the heat will hold and may worsen to the left of the weakness. The south central states will roast through the next week or so, and possibly longer. Eventually, the "Sonoran + Bermudan" ridge complex will reform, and the hot air will surge north and east again. On that note the arrival of another shortwave will target the north centra; and Great Lakes states on Tuesday with a probable severe weather (hail, tornado and high wind) outbreak.

Watching The Gulf Of Alaska Low And Ejecting Cold Fronts Along The Canadian Border (For Thunderstorm Threats In The Northern Tier)

METEOBLUE

UQAM Meteocentre (3)

TwisterData.Com (3)

University Of Wisconsin Weather Server (3)

College Of DuPage Weather

It is because of the constant presence of a strong, regenerative Gulf of Alaska Low that a cool/changeable Canada vs. a usually hot USA will be in play through at least mid-August. The heat ridge complex straddling the country is also a contributor, but the cold pocket of energy that comes into British Columbia and Alberta is the chief driver. Every time a disturbance ejects eastward form the parent 500MB cyclone, thunderstorms will erupt along and either side of the surface thermal boundary. That set-up seems very stable, and can easily create an environment for severe thunderstorms. Watch the next threat zone emerge on Monday night into Wednesday from the Dakotas into Michigan into Wisconsin and Illinois, which could spawn a dangerous severe weather event (Lifted Index of -15 in the warm sector against string surface convergence).