WEATHERAmerica Newsletter, Saturday, July 13, 2024; MEDIUM RANGE OUTLOOK

[Larry Cosgrove]

MEDIUM RANGE OUTLOOK

(Four To Ten Days From Now)

 

Will The Bermuda High Hold Off The Trough And Cold Front ?

ECMWF (4)

PivotalWeather.Com (4)

A large, persistent gap or weakness has emerged over the area between the Rocky Mountains and Appalachia. The Bermuda High has been very strong and pulsing of late, which essentially holds any cold advection from Canada at bay and allows for consistently warm and humid conditions along the Eastern Seaboard. It appears that the medium range will see the frontal structures perhaps reaching the Atlantic coastline, if only temporarily. This will be an opportunity for shower and thunderstorm production along the Interstate 81 and 95 corridors, which need the moisture anyway. But in the 6-10 day period and going forward, the offshore ridge component to this pattern will expand from time to time, maintaining the generally hot West and East vs. mild Central configuration.

And Will The Mexican Monsoonal Fetch Overtake The West?

UQAM (4)

TwisterData.Com (4)

TrueWx.Com (4)

College Of DuPage Weather Laboratory

Most of the model guidance at 0z July 14 has come around to the idea that the monsoonal moisture fetch in Mexico will reach the American West in this time frame.Rainfall along the Mexican Cordillera should be exceptionally high, and high dewpoints will ultimately get sucked into the intense Sonoran heat ridge that will be centered over of just west of the "Four Corners". It will take a series of days for the process to work its proverbial magic and force relocation of the heat ridge complex further eastward, which might facilitate linkage with the Bermuda High. This is why the temperature forecasts along the West Coast and into the northern Intermountain Region. There may be a heat surge out of the northern High Plains as we move into the last week of July, with a derecho or MCV risk in the Upper Midwest and Great Lakes.