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Severe Weather 2020 (1 Viewer)

This severe weather season will be?

  • Much Above Average

    Votes: 4 9.3%
  • Above Average

    Votes: 26 60.5%
  • Average

    Votes: 6 14.0%
  • Below Average

    Votes: 5 11.6%
  • Much Below Average

    Votes: 2 4.7%

  • Total voters
    43
  • Poll closed .
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bwalk

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Messages
391
Location
North Prattville, Al
Pretty nasty comma head here


Lots of wind damage (straight line) as well as a tornado in Arlington from that storm.

"The Arlington Fire Department tweeted shortly before 10:00 p.m. that crews were responding to multiple locations with reports of collapsed buildings."

 

bwalk

Member
Messages
391
Location
North Prattville, Al
Tornado watch is up for most of the coastal mid-Atlantic. 40/20 probs.


BULLETIN - IMMEDIATE BROADCAST REQUESTED// Severe Thunderstorm Warning
National Weather Service Mount Holly NJ -- 449 PM EST Mon Nov 30 2020

At 448 PM EST, a severe thunderstorm was located over Newport Meadows, or 8 miles west of Bridgeton, moving northeast at 50 mph.
HAZARD...60 mph wind gusts.
 

Fred Gossage

Member
PerryW Project Supporter
Messages
167
Location
Florence, AL
Kory and I have been looking at data and discussing things the past few days. MJO looks to be going toward a position a bit more typical of La Nina as we head forward, and AAM looks like it's going to start tanking soon. I would start keeping an eye on medium range guidance for one or more severe weather threats to start showing up between now and Christmas or so. No real specifics other than that, but it may be time to start having our eyes open...
 

Weatherphreak

Member
Messages
144
Location
Huntsville
GFS is showing a system on the 15th and another on the 18th with 60 dewpoints as far north as Nashville and warmer temps prior to the systems. I don't know what to look for in the wind fields but this may be what is being referenced? Not uncommon to have some rough weather this late in the year for Alabama and Mississippi.
 

Fred Gossage

Member
PerryW Project Supporter
Messages
167
Location
Florence, AL
GFS is showing a system on the 15th and another on the 18th with 60 dewpoints as far north as Nashville and warmer temps prior to the systems. I don't know what to look for in the wind fields but this may be what is being referenced? Not uncommon to have some rough weather this late in the year for Alabama and Mississippi.
I'm waiting for a few more sets of model runs to watch for at least the first signals of consistency, but so far, the general idea has been there on multiple GFS runs now... as well as support in the Euro ensembles and the Canadian. There is a growing signal. I think the first time period we have to watch is the 12th-14th, maybe stretching toward the 15th if the system were to lean slower.
 

Fred Gossage

Member
PerryW Project Supporter
Messages
167
Location
Florence, AL
Looking more and more likely that we may get a +TNI configuration heading into spring based on latest Nino 4 and Nino 1.2 data with the former cooling and the latter warming.
The latest PDO for November is in... depending on what source you use, it's -1.55 or -1.71. HUGE drop, and way ahead of any modeling. Here is latest value compared to CFS, for example, which is this far behind but still gets it to -2 by April...

1607105084431.png
 

Fred Gossage

Member
PerryW Project Supporter
Messages
167
Location
Florence, AL
So what's the implication of the TNI and PDO numbers for severe weather? Is there a correlation?
Those two things being what they are are major red flags for Dixie Alley severe as we head into late winter and spring. These are the two large scale teleconnections that help the La Nina itself drive the classic severe weather pattern you see in years like 1974, 2008, 2011, etc, etc. It doesn't mean an event of that magnitude will happen, but the door isn't locked shut for it like it is other years, and these are the large scale conditions that are in place when big events in Dixie happen.

To better understand the TNI, do a search for the Trans-Nino Index and how it relates to tornado activity. There are a couple of articles that come up.
 

warneagle

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2,146
Location
Arlington, VA
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Those two things being what they are are major red flags for Dixie Alley severe as we head into late winter and spring. These are the two large scale teleconnections that help the La Nina itself drive the classic severe weather pattern you see in years like 1974, 2008, 2011, etc, etc. It doesn't mean an event of that magnitude will happen, but the door isn't locked shut for it like it is other years, and these are the large scale conditions that are in place when big events in Dixie happen.
Okay, thanks for the explanation. My knowledge of large-scale climatological stuff is sorely lacking.
 

warneagle

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Location
Arlington, VA
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Looks like we'll get our first proper low pressure system of the winter next weekend (in the range y'all were discussing upthread).

Meanwhile, we're getting our first proper nor'easter of the winter today and tomorrow. No snow this far south, thankfully.
 

MattW

Member
Messages
158
Location
Decatur, GA
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Yep, GFS staying consistent with a system late next week. To my eyes it looks like it's going to be one of those tricky systems where classic, textbook energy and dynamics aren't anywhere close, but still plenty of potential for something dangerous.
 

Taylor Campbell

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892
Location
Wedowee, AL
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The GFS is hinting at perhaps a significant event or two late next week the 17-18th and the week following it.
 

Fred Gossage

Member
PerryW Project Supporter
Messages
167
Location
Florence, AL
I think the biggest problem for the next couple of weeks going forward is that the pattern is a little too active, without stronger ridging just southeast of us. We have too many systems frequently sweeping through with none of them ejecting northeast. They are all sweeping straight across and sending their cold fronts down through the Gulf, and then the next one comes in before there is any time for quality moisture recovery at all. Until/unless that changes, the pattern will be active and there will be dynamic storm systems... telegraphing to us what the pattern is capable of, but there will be very little in the way or appreciable or significant severe weather. IF we get one of these to eject northeast and stall its front out along the Gulf Coast though, it would be game on for the next system right behind it.
 
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