Fall 2025 WX Discussion Thread

[jaxjagman]

Could break the record high Sat around here ahead of the CF,possibly even some severe storms,we could use some rain again here,we've went into a lull lately once again with any liquid

[Carvers Gap]

La Nina is just HOT in my backyard during fall.  It has not been as hot as some years, but it is still very warm. Nights have been cool.  It is almost like living in the desert with such low humidity.  Leaves here are definitely in a state of suspended animation after some cold days in August and early September.  Now, that we have switched firmly back to summer...everything is paused.  Leaf season will run into early winter here.  

There are some hints that cooler weather is coming.  The CFSv2 has an outright flip at 500 while the Euro Weeklies are typically blind to it.  That said, the Euro Weeklies control doesn't have the flip.  Usually if a flip is about to occur, I like to see the Euro Weeklies control and CFSv2 both showing something similar.  Until we see that, I look for at least 2-3 weeks more of very warm weather...maybe longer, but that is pushing the envelope as the pattern will be due for a change sometime around mid-November.  

Ideally, we want the pattern to flip during the last week of November or first week of December.  Then, maybe we can get 4-6 weeks of a pattern which could yield winter weather.  What we don't want is the pattern to flip cold in early November.  If it does that, that means it may well flip back warm by mid December and hold through most of January.  That is a concern and very much on the table.  

[Carvers Gap]

I strongly encourage everyone to read @John1122's posts in the winter discussion thread.  Why?  Because what I am gonna say next kind of dovetails into those comments.  Both the 0z GEFS and GEPS are depicting a pretty significant(?) pattern reset to begin November.  That kind of fits the 4-6 week pattern cycle of the past many years.  Ridge slides west, and a trough develops in the central and eastern part of the United States.  That could be a SHARP change in temps given the summer like temps we are experiencing right now.  We are talking 20-30 degree differences in high temps.  The Euro weeklies don't see this just yet, but they often get roasted during shoulder season...before often locking in the winter pattern by mid Dec.

The 13-14 analog also had a sharp change in temps by November....

[Carvers Gap]

Just and addendum to the post above....the Euro Weeklies(control) does have a sharp downturn in terms by week 2 of November.   The Weeklies ensemble has this as well.  The CFSv2 yesterday morning started to show some hints of this.  Let's see where this goes.  Obviously, this could be a head fake at this lead time, but this fits with what we know about Nino climatology.  It would not surprise me to see snow in the air by mid November, especially for foothills and mountain locations.  It appears that summer is finally on the clock!  I mean it has to be by mid November, right?

[Carvers Gap]

Just toggling between the (3) weeklies (American, Euro, and Canadian)....there is blocking showing up over Greenland or slightly west of it in the Davis Straits.  That is usually a pretty good sign that cold is coming.  One thing to watch for is what the Pac does.  If it is meh...periods of zonal flow could persist w/ maritime air flooding the continent.  If the EPO or PNA fires up, then very cold air could head south.  Some runs have the AN heights over the northern Hudson Bay....to me that is a crapshoot as to whether that helps us or not, and that is not a true NAO.  If coupled with a good Pac, that works.  Otherwise, zonal.

[John1122]

Finally seeing 30s show up in my point forecast. Not sure if it will frost next week but I suspect it will on the day I'm predicted to get to 37. I'm usually cooler than forecast in the bowl I live in. 

[John1122]

Leaf color has hit the fast forward button all of a sudden the last 48 hours. A large maple that turns bright golden has went from fully green to 2/3rds turned since Wednesday. 

[Matthew70]

I am enjoying these temps.  My new grass is beautiful!  Yeah I had to water it heavily until it germinated.  Now it’s easily 2”-3” tall.  I’m touching up a few areas that need to be seeded some more but with the temps next week after the rain, the fescue will thrive as it already has.