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Potential active plains period next week...

The GFS has been in pretty good agreement from run to run, with a deepening trough bringing in strong flow over the southern plains by mid-week. This trough will also help in significant moisture return, with a narrow moist axis containing >60 Td's across TX/OK/KS by Wednesday per the latest GFS. This deep gulf moisture, when combined with low 80's temperatures, should yield sufficiant instability. In addition, the strong speed/rotation through a rather deep-layer will support organized severe thunderstorms... And given the strength of this system at this time of year, it could spell out a classic "fall" event. It's WAY to early to tell yet, but I just that I'd open a thread for free discussion for this system...

--> http://www.spc.noaa.gov/products/exper/day4-8/
 
I looked at it, but noticed the northeasterly flow across the entire eastern Gulf of Mexico that the GFS is forecasting until Tuesday night.... That screams "recirculated continental air" (or modified), that we all know so well from this spring (and 2002).
 
Boy if all I looked at was 500mb flow I'd be getting excited.....wish it was May LOL.

Actually - my main worry with this setup is that the main mechanism will be cold front. I looked at the surface temps and it screams cold front to me. I've chased enough anafront junk to shy away from that sort of setup.....but all will become clearer nearer the time I guess.

KR
 
yea I kinda have to agree with Karen, arent we alil late in the year to expect anything more than some cold core sups?
However, given all the strange global weather ANYTHING is possible, I'd have to be in TX right now b4 I'd sign up for a chase....

Keep ther heat on.....who knows?
 
Thanks for the stats Mike - on average about 1 per October if I read it right, not an overly impressive number but none the less a number.

I know its way out on the models so we will need a few more days for unfolding, however at least its something more than we have had ...
I don't think thee has been an SPC hail/wind report in 3 days!
 
I am not terribly excited about this system, but it would definitely be a chase day if the GFS verified. Due to the stacked low, there is poor directional shear, which does not bode well for tornado potential. The cold core target could be there though. I am hoping the upper level low will evolve as more of an open wave. If this happens and we get decent moisture, we might be in business.
 
Originally posted by Karen Rhoden
Boy if all I looked at was 500mb flow I'd be getting excited.....wish it was May LOL.

Actually - my main worry with this setup is that the main mechanism will be cold front. I looked at the surface temps and it screams cold front to me. I've chased enough anafront junk to shy away from that sort of setup.....but all will become clearer nearer the time I guess.

KR

No, it's not... A pronounced dryline develops across western KS/OK/TX by Wednesday, with the cold front being much further to the north, roughly located from northern IL into western OK. I'd have to agree on the rather poor directional shear, yet this event is still nearly a week away - so it has plenty of time to shape up.

Dryline --> http://www.rap.ucar.edu/weather/model/gfs1...hr_sfc_dewp.gif
Coldfront --> http://www.rap.ucar.edu/weather/model/gfs1...hr_sfc_temp.gif
 
Originally posted by nickgrillo+--><div class='quotetop'>QUOTE(nickgrillo)</div>
<!--QuoteBegin-Karen Rhoden
Boy if all I looked at was 500mb flow I'd be getting excited.....wish it was May LOL.

Actually - my main worry with this setup is that the main mechanism will be cold front. I looked at the surface temps and it screams cold front to me. I've chased enough anafront junk to shy away from that sort of setup.....but all will become clearer nearer the time I guess.

KR

No, it's not... A pronounced dryline develops across western KS/OK/TX by Wednesday, with the cold front being much further to the north, roughly located from northern IL into western OK. I'd have to agree on the rather poor directional shear, yet this event is still nearly a week away - so it has plenty of time to shape up.

Dryline --> http://www.rap.ucar.edu/weather/model/gfs1...hr_sfc_dewp.gif
Coldfront -->http://www.rap.ucar.edu/weather/model/gfs156hr_sfc_temp.gif[/b]

Well, you have the dryline going for you. The SFC low deepens a bit and you have increased low level shear not to mention these long term models do not pinpoint mesolow's at all. I think it has a descent chance to shape up into something. Here in Alabama we are known for our fall/winter torando outbreaks. Some to mention...

12/16/2000
11/25/2001
11/10/2002
11/24/2004

More in the making??? All of our systems came out of the southern/central plains.
 
I'm not getting my hopes up on this one either. Things just aren't looking too favorable for a "major" outbreak at this point. I think there may be some potential for a few isolated events at best, but the scenario right now doesn't look too favor anything widespread.

I guess this late in the year, my confidence goes way down on these systems, especially if they're several days out. Bill's right though, anything could happen since the climate has been really screwy the past few years. Something worth watching though.
 
GFS has been pretty persistent with a DL setup from W OK down through TX. Now whether or not it will stay that way is up in the air (let’s hope it doesn't take KRs thoughts to heart :wink: ). It's so hard to focus on what is good about this system being that is still so far out, but attm I do not like the 3km directional shear which is typical of these cold core setups. Plus, as usual, moisture will be of concern.

Regardless of how it looks now I am still making plans to take off work. Better safe than sorry. Man could I use another Oct tornado. It's been far to long....

Mick
 
Seriously, no idea why people would constantly look down at this setup... Besides from the fact it's still a good 4 days out, it's been extremely consistant from run to run. Take a good look at wind fields, and you'll notice quite a few simularities between 10-9-2001 and Wednesday. Both setups had good low-level veering, and strong southwesterly flow aloft -- and had a dryline featured in the same area. There is plentiful moisture for this setup... You'll have a solid 2 days of open gulf streaming into the southern plains - as the flow becomes much more southerly by Tuesday evening.

Seriously, there is not much difference between the 10-9-2001 and this potential event... This event could either end up as a loosely organized event, or it could indeed be an outbreak. The strong flow at every level, combined with the good veering in the SFC-3km layer will yield sufficiant deep-layer shear profiles favorable for supercells. In addition, deep gulf moisture and SFC temperatures forecasted >80F should yield strong instability. Yeah, it's still 4 days out... Seriously, though, there is no reason to say why it "won't" be an outbreak, because it VERY well could (and it may not be).
 
Originally posted by nickgrillo

Seriously, there is not much difference between the 10-9-2001 and this potential event...

One big difference between 10-9-01 and this system (attm) is that 10-9-01 was not a cold core setup as is with this system. The low is simple stacked and that doesn’t help the 3km directional shear IMO.

Here is some stuff on 10-9-01. What a chase day. WOW!
http://www.spc.noaa.gov/exper/archive/even...1009/index.html

Mick
 
Hmmmmm, not sure what to think of this as of the latest gfs. It isn't as stacked of a system and should have a chance at some decent directional shear. The big problem like has already been mentioned is the recycled air.

http://www.rap.ucar.edu/weather/model/disp...hr036hr156hr060

Watch the flow over the gulf. Not good.

http://www.rap.ucar.edu/weather/model/disp...hr036hr156hr060

It doesn't seem to be a TERRIBLE gulf whacking, but it doesn't look good by any stretch either. I seem to remember thinking of a similar thing Oct 9, 2001, thinking no way the juice would made it. Not only did it make it but well into c Nebraska, thanks to a very strong low level jet. I don't recall the surface pattern leading up to it though. SPC page doesn't seem to want to show the sfc and I'm too lazy to pull it up somewhere else like plymouth.

Hmmm, ok, looked just briefly. Oct 7 DFW had a TD of 45 at 21z. Then up to 61 by the 8th. That followed some decent offshore flow on the 6th. BUT, on the 5th there was low-mid 70 TDs well into S TX. I think the odds of getting the juice there was in place on Oct 9th is less just looking at prog'd sfc winds. But, there seems to be some chance out there worth hoping for.

http://www.rap.ucar.edu/weather/model/disp...ours=hr132hr156

http://www.spc.noaa.gov/exper/archive/even...9/250-oa-00.gif

Those 2 are a good deal different though. Lets just hope for less gulf whacking and less cuttoffness and we might be in luck.
 
I also dislike the current cutoff nature ther GFS is showing - from the 108 to 156 hour at 300mb, the initial closed upper low gets more and more cutoff from the polar jet, and continues to weaken as it slowly moves east from CA.
GFS has the polar jet staying way up in Canada.
From a quick browse at the October events for OK on the SPC's 'Severe Thunderstorm Events' page, the events shown all seem to be associated with a western conus dip in the polar jet stream. I want to search some more on the SPC Events site for examples of closed upper low days and see if any have ever led to outbreaks, currently am not sure, but I'd guess the storms would not be as good as with a fast moving shortwave under a strong longwave 250mb trough.
 
The GFS has slowed down the progression of the trough, by around 12 hours or so. A dryline develops over the western TX panhandle on Wednesday, with the GFS initiating precip ahead of the dryline by 0z Thursday. I'd have to think the 36hrs of forecasted southerly flow should be able to advect in deep gulf moisture. The low is much less stacked, and there is pretty decent veering in the 0-3km layer - and speed shear is good at pretty much every level. There should be enough moisture to get things going, with widespread >60 Td's progged to advect into the panhandle warm sector.

A few more hours until the new 0z runs (whistles the theme to Jeopardy) :lol:
 
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