WEATHERAmerica Newsletter, Saturday, April 6, 2024; EXTENDED PERIOD FORECAST

[Larry Cosgrove]

EXTENDED PERIOD FORECAST

(Between Day 11 And Day 15)

 

Severe Thunderstorm Threats Likely To Emerge Over The Southern And Eastern Portions Of A Warmer USA

CIMSS (2)

NOHRSC (2)

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

NOAA/PMEL

NOAA/CPC

ECMWF

HPRCC/University Of Nebraska (2)

Environment Canada

ECMWF (3)

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

ECMWF

With El Nino likely to do a quick turn to La Nina, the interest in heat waves and hurricanes is growing rapidly. But we still have about a month or so to go before we see full meteorological impacts in the U.S. and across Eurasia.

In the meantime, note that the Pacific Basin remains very active with many deep storms and a very impressive subtropical jet stream. Using 1973, 1995, and 1998 as analog inputs, it seems likely that we are going to see some brutal convective impacts from the field of disturbances. Until the heat ridge complex across the Caribbean and Sargasso Seas "makes its move" (probably in the second week of May), convection from KS, OK, and TX through the Ohio and Tennessee Valleys and Mid-Atlantic is going to be a real problem. The track scenario is a very volatile one with respect to tornado, hail, and flooding rain threats. Typically, the West will be cooler than normal. But as you will find out, some of the warmth will form across the Intermountain Region and then spread through the eastern two-thirds of the country.

If you look at the temperature and 500MB anomaly predictions, bubbles of warm air advance in front of each trough/storm migrate across the lower 48 states. But the real heat waves, and there should be plenty, will lurch from south to north once the polar and subtropical jet streams shift to higher latitudes. I am thinking that we will plateau at a moderate La Nina, following the ECMWF and IRI modeling plumes, probably by October 1. The preliminary hurricane forecast I made is a bit more conservative than what I am seeing with CSU and NOAA sources, if only because the upper westerlies may stick around into mid-August. That said, my call of 18N/10H/6MH implies risks to both the Gulf and Atlantic shorelines, and may still be an issue through Halloween.

For now, just concentrate on severe weather and flooding rain risks, I will present outlines for extreme heat and tropical cyclones in coming weeks. And the forecast will not be dull, believe me.

 

Prepared by Meteorologist LARRY COSGROVE on 
Sunday, April 7, 2024 at 1:00 A.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 2024 by Larry Cosgrove

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