Fall 2012 wx discussion

Some unelevated locales may reach the freezing mark for the first time this season tonight into the AM

6z 4km NAM lows

Fall colors are really starting to show near my neck of the woods..I took these up near Del Rio, TN yesterday!




Meanwhile..they are getting ready to peak above 4000 ft!

Had a decent frost this morning at my house (about 20 miles east of downtown Nashville).

Very frosty 32 this morning, but I'd long since had a killing frost.

Amazing, but my tomato plants are still hanging on. Best, and longest, growing season I've ever had.

1.3 inches of rain so far for the month of October.. says my wx station.

I noticed it got into the 80's out towards the Memphis area today. Enjoy the shortlived warmup while you can the next couple of days because another cold intrusion looks likely in the extended.

Models have came into better agreement with system that was in the extended. Teleconnection signals along with guidance models favor an intense storm system over the eastern US during the Oct 18-20th timeframe. This system will carry the possibility of severe storms in the OH and TN valleys along with the possibility of cold advected snow showers in the Appalachians/OH valley!!

Toot wrote:I noticed it got into the 80's out towards the Memphis area today. Enjoy the shortlived warmup while you can the next couple of days because another cold intrusion looks likely in the extended.

Models have came into better agreement with system that was in the extended. Teleconnection signals along with guidance models favor an intense storm system over the eastern US during the Oct 18-20th timeframe. This system will carry the possibility of severe storms in the OH and TN valleys along with the possibility of cold advected snow showers in the Appalachians/OH valley!!

yep, 85 degrees for high today... actually even mowed the yard late this afternoon.

Toot wrote:I noticed it got into the 80's out towards the Memphis area today. Enjoy the shortlived warmup while you can the next couple of days because another cold intrusion looks likely in the extended.

Models have came into better agreement with system that was in the extended. Teleconnection signals along with guidance models favor an intense storm system over the eastern US during the Oct 18-20th timeframe. This system will carry the possibility of severe storms in the OH and TN valleys along with the possibility of cold advected snow showers in the Appalachians/OH valley!!

but its the same song, tune and dance... both euro and gfs has the main energy way north again on this one also... looks like a possible linear type with iso severe... i like the looks of the euro on long range for a big system around last week of month... that one has the possibility to be further south as better blocking signals start to take shape... euro isnt to bullish with the cold as gfs is

Moisture is crap, I strongly doubt we'll see much of a severe threat with the system next week, regardless of how strong it is.

andyhb wrote:Moisture is crap, I strongly doubt we'll see much of a severe threat with the system next week, regardless of how strong it is.

i agree 100 percent on that... return gulf flow looks very meager... o well maybe later in the month

Well, the 00z Euro is a bit more intriguing, has a secondary SLP further south that advects the first signs of instability I've seen for this system, given the very strong shear, that is mildly interesting at this juncture.

latest ruc looks interesting in the re development later in the early afternoon...already a dry punch has occure over eastern arkansas.. and the cold front still pretty far back west near the arkie n okie border... turning of the winds seem to be directional far a part of the afternoon also... think spc map of 5 percent torndao risk is pretty reasonable to me... we ce what happens later

tennessee storm09 wrote:but its the same song, tune and dance... both euro and gfs has the main energy way north again on this one also... looks like a possible linear type with iso severe

I wouldnt underestimate this systems potential. Im not saying its gonna be big deal or anything but it is kind of odd that all guidance models are progging this one into the 980mb range and some are even going further into the 970Mb range. There are several signals that suggest this is gonna be an intense system. You seem to have forgot a storm that had its center displaced WELL north of here (Just like this one is progged) just two years ago in the month of October.

SPC storm reports for Oct 26 2010


Satellite images from Oct 26 2010


NARR reanalysis for Oct 26 2010





And finally todays 12zGFS is progging this one as low as 977Mb


That is a big boy low pressure system right there

Toot wrote:

tennessee storm09 wrote:but its the same song, tune and dance... both euro and gfs has the main energy way north again on this one also... looks like a possible linear type with iso severe

I wouldnt underestimate this systems potential. Im not saying its gonna be big deal or anything but it is kind of odd that all guidance models are progging this one into the 980mb range and some are even going further into the 970Mb range. There are several signals that suggest this is gonna be an intense system. You seem to have forgot a storm that had its center displaced WELL north of here (Just like this one is progged) just two years ago in the month of October.




That is a big boy low pressure system right there

great point there toot, yeah i remember that particular system...cause we didnt get as much as areas to the north and east of me... o trust me i have seen some nice systems effect us even if the slp was way north... and yeah 970 mb... now thats a strong low buddy... still lot depends on return flow of low level moisture, course get a little more instability will only help.

Last few runs of the Euro remind me a lot of last years pattern in the fall.

The problem is that s/w that dives southward out of the Rockies from 36 hrs on that cuts into the Gulf and kills the chances we have for moisture advection, and it has been shown by virtually all the models, so I don't think there is going to be much severe with this, unless that s/w is weaker than progged by guidance currently.

snowdog wrote:Last few runs of the Euro remind me a lot of last years pattern in the fall.

Yep. Big cut off lows and negative pna. Though it looks less negative today than the last couple runs.

snowdog wrote:Last few runs of the Euro remind me a lot of last years pattern in the fall.

If the analogs are correct for November the pattern should become aligned in a less blocky config in the higher latitudes at 500mb and possibly a warm alignment in the +NAO/AO -PNA indices. Im expecting Nov to be the warmest month of the fall!

Well, the NAM is interesting, gets some noteworthy instability into the Ozarks, which would be more than enough to support a severe threat given the strong dynamics associated with this trough, although this is the NAM in the later portions of its run, so take this with a grain of salt.

The 18z GFS also indicates a very large upper trough developing across the western half of the country towards the end of its higher-res range, with a powerful Pacific jet diving down its backside, monitor this for future model continuity, the Euro has had something similar to this for several runs in a row now.

As you see on the 15z SREF, the probability of getting 60s dews to Cairo is fairly high, as well as getting 200+ m2/s2 of 0-3 km SRH...

andyhb wrote:Well, the NAM is interesting, gets some noteworthy instability into the Ozarks, which would be more than enough to support a severe threat given the strong dynamics associated with this trough, although this is the NAM in the later portions of its run, so take this with a grain of salt.

The 18z GFS also indicates a very large upper trough developing across the western half of the country towards the end of its higher-res range, with a powerful Pacific jet diving down its backside, monitor this for future model continuity, the Euro has had something similar to this for several runs in a row now.

yea, andy i still like the looks of the pacific jet streakiing out west in longer range...

andyhb wrote:As you see on the 15z SREF, the probability of getting 60s dews to Cairo is fairly high, as well as getting 200+ m2/s2 of 0-3 km SRH...

IMO dewpoints and any aspect of warm advection is probably severely underestimated by models at this point.

Guidance models suggesting a Pattern change is incoming. Mean troff to setup over the western US. This will mean warmer weather in the east. Ideally this will setup a colder pattern as we get close to the end of November. Im thinking December starts off with a bang!

I like this

http://t.co/VOHYkw0K