WEATHERAmerica Newsletter, Saturday, August 2, 2025; EXTENDED PERIOD FORECAST

[Larry Cosgrove]

EXTENDED PERIOD FORECAST

(Between Day 11 And Day 15)

 

At This Time Of Year, It Is Always About Heat And/Or Hurricanes!

CIMSS (3)

WMO/GRAPES Beijing

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

NOAA/PMEL

NOAA/CPC

HPRCC/University Of Nebraska (4)

Environment Canada

TropicalTidbits.Com (Dr. Levi Cowan) (5)

WeatherBELL (3)

It should come as no surprise that most eyes and ears are looking at the potential for heat ridges and tropical cyclone threats. Even a cursory look at the attached maps shows lots of excuses for hot weather in the lower 48 states. And the forecast models and respective analogs are opening up threats for both "home grown" and "Cape Verde" storms. The two trends in the weather summary may actually be interrelated. One thread that the viewer must understand is that when the subtropical highs are linked (as in the current Sonoran + Bermudan configuration), there is less of a chance for a storm to target the lower 48 states. You see, any impulse will need a break between anticyclones in which to recurve and gain latitude. As long as no polar jet stream systems are involved (more of a problem after the second week of October), the approach and landfall will not have difficulties with shearing wind profiles and dry intrusions that would kill convective circulations. Some incoming cold core disturbances can aid intensity if the warm-core entity encounters a neutral or negative tilt low center (difluence present in the upper levels that enables strengthening). But in August, the "possibles have to dodge the presence of the Saharan Air Layer (now weakening) and move into land areas in the early life stages of the cyclone. The waters in the western Atlantic Basin are warm enough (and getting warmer), so most of the parameters for a meaningful tropical event are appearing.

The questions are when, where, and how strong? On the idea that a longer term storm will enter a weakness, then Texas and Louisiana seem possible. Linkage on the Pacific Basin features indicates lots of heat ridging from the Southwest on into the St. Lawrence Valley and New England. The ECMWF weeklies have a gap emerging in the western and central Gulf Coast. That system would have to come from the Lesser Antilles through the Caribbean Sea after August 15. Low pressure in question is evident on most of the ensemble members either above or below the major islands, hitting its stride at a time when the ridging starts to cleave, just like it has done since June. You will note the very obvious gap in temperature and precipitation in the monthlies across western and central portions of the Lone Star State, which is where the vector wind anomalies in the analog set put the weakness this month. The West Coast may be cool, and the monsoonal moisture fetch may reform, thus keeping the Sonoran subtropical high in the Ozark Plateau. If so, the new month could be "one to talk about". Providing one of the ITCZ disturbances or diffuse frontal structure creates a candidate storm.

 

Prepared by Meteorologist LARRY COSGROVE on 
Sunday, August 3, 2025 at _:__ P.M. CT

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 2025 by Larry Cosgrove

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