EXTENDED PERIOD FORECAST
(Between Day 11 And Day 15)
The Split Flow Aloft Is Starting To Emerge! What This Means For The Evolving Autumn And Winter Weather Pattern
CIMSS (2)
TropicalTidbits.Com (Dr. Levi Cowan) (3)
NOAA/PMEL
NOAA/CPC
University Of Nebraska/HPRCC (2)
Environment Canada
ECMWF (3)
TropicalTidbits.Com (Dr. Levi Cowan) (5)
With the gradual breakdown of the Summer 2023 Sonoran heat ridge configuration, there are signs of the emerging weather trends for calendar autumn and winter. This is a slow process, mind you. There will be no credible solutions to the usual “How much for Philly?” or the “El Nino always means mild, right?” questions. But the oceanic thermal anomaly patterns and ENSO sector forecasts seem to be pointing toward a “typical start” and “interesting ending” scenario that starts with a tumultuous October outlook that may have some drawing on memories of spring.
Now let me explain. When you look at the ECMWF and CFS outlines at 500MB, you can clearly see a split flow emerging. A stretch of warm and dry weather across the southern half of Canada (which may mean more fires) and the southern branch jet stream across the USA along and below 40 N Latitude. Thunderstorms seem very likely with the subtropical stream since the higher wind velocities and cold pools aloft act to suppress a very impressive Mexican heat ridge (into Baja California and the central Mexican states). This displacement almost always increases precipitation potential in the familiar California/Texas/Georgia arc, much like what we saw in 2013. The imprint of the higher winds aloft seem to be setting up now over the eastern Pacific Ocean, dredging moisture from the remnant field deposited by Hurricane Jova,
I will be watching to see if the flat ridging in Canada, along with its vast area of warm and dry conditions, starts to back up and amplify into the Yukon and Northwest Territories in November (using the 2009 analog). The recent warming of the 4 and 3.4 sectors vs, cooling in the 1.2 zone and Atlantic Basin points toward a Modoki formation, but probably not starting until December, and accelerating in the second half of winter. It is too early for particular forecasts (and it would not be wise to look at specifics until mid-October at the earliest). But if you point the dart at a normal-with-cold-spikes outcome for NDJF, that might prove workable,
Prepared by Meteorologist LARRY COSGROVE on
Saturday, September 16, 2023 at 11:15 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.
Saturday, September 16, 2023 at 11:15 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 2023 by Larry Cosgrove
All rights reserved.
This publication may not be reproduced or redistributed in whole or in part without the expressed written consent of the author.
This publication may not be reproduced or redistributed in whole or in part without the expressed written consent of the author.