Severe WX January 10-12, 2020 Severe Weather Forecast Thread

[Equus]

I honestly can't remember the last time central AL has been in a 30% especially this far out on the D4-8. Very very intrigued here.

 

[GA Stormchaser]

From an old Talkweather veteran, Matt Grantham and his morning AFD out of BHM....

(excerpt)
Higher rain chances are expected on Friday as a trough matures over
Texas and New Mexico, leading to the onset of stronger deep-layer
southerly flow. This will support a wide warm sector Friday night
into Saturday ahead of a strong shortwave taking on a negative
tilt. This shortwave appears poised to take advantage of the high-
quality warm sector, with strong dynamics in close proximity to
and aimed directly at the warm sector. In other words, this has
the potential to become a significant severe weather event, and
models have been rather consistent in this regard. At minimum,
strong forcing would result in a QLCS capable of producing
widespread damaging winds and embedded tornadoes.

The potential for supercells ahead of the QLCS will depend on the
state of the warm sector. At face value, models indicate CAPE
values of 500-1000 J/kg, but this could be too low. If the warm
sector is relatively uncontaminated, temperatures would rise into
the lower to mid 70s during the late morning and early afternoon
hours on Saturday, aiding in the formation of cellular convection
ahead of the QLCS. Due to unusually good model consistency, our
threat confidence will be raised to a 3 out of 5 in the HWO.

 

[Lori]

Jan 2012 and Jan 2013 comes to mind!!

 

[tennessee storm chaser]

Jan 2012 and Jan 2013 comes to mind!!

number one analog was being used is super Tuesday February 2008, number two November 2004 event

 

[JayF]

Interesting Tweet from Rob Elvington. 3 days with Precipitable Water outside the normal range in a short period of time.

 

[Xenesthis]

number one analog was being used is super Tuesday February 2008, number two November 2004 event
[/QUOTE
It looks to me like the instability will be limited to MS/AL. What do you think?

 

[CheeselandSkies]

The lapse rates being progged over the Arklatex into the lower MS Valley Friday afternoon and evening really made me sit up and take notice. Often those are a better bellwether of the potential for robust updrafts than raw CAPE values in cool season setups. That said, I'm also seeing some 850-500mb VBV in NAM forecast soundings from the most unstable areas. Shear profiles *may* not be quite as supportive of sustained tornadic supercells as they were on December 16th.

Sent from my SM-G955U using Tapatalk

 

[Richardjacks]

In looking for threat-limitig factors in north and central Alabama, here is what I see-
-Possible warm sector contnination due to morning warm frontal passage bringing associated widespread showers and low level clouds. While this may limit the threat for a widespread event, I still think tornadoes are possible just fewer of them but a strong one cannot be ruled out.

-storms along the gulf, this would obviously reduce the risk to much further south.

 

[tennessee storm chaser]

mostly agree with you, though 12zuero did trend the slp just tad more north... trend? who knows... but do think ms and alabama are in the better environment for tornadoes

 

[tennessee storm chaser]

mostly agree with you, though 12zuero did trend the slp just tad more north... trend? who knows... but do think ms and alabama are in the better environment for tornadoes

quoting xenthesis

 

[Liberty4dayz]

Man oh man...it sends chills down my spine hearing it compared to Super Tuesday. I lived in Memphis at the time, and was at work less than a mile from where the ones who lost their lives were. I love going back and watching Dave Browns coverage on WMC-TV...when he utters the phrase... " Ok, folks this is how serious this is....a Tornado Emergency has been issued for Shelby County....I....well....ive never heard of one these folks..." Chills I tell ya...

 

[tennessee storm chaser]

Man oh man...it sends chills down my spine hearing it compared to Super Tuesday. I lived in Memphis at the time, and was at work less than a mile from where the ones who lost their lives were. I love going back and watching Dave Browns coverage on WMC-TV...when he utters the phrase... " Ok, folks this is how serious this is....a Tornado Emergency has been issued for Shelby County....I....well....ive never heard of one these folks..." Chills I tell ya...

if the euro is correct... think the Memphis area may have to deal with the possible triple point threat... were the frontal boundary and slp ride along at... can spawn a tornado or two along that

 

[Equus]

I really wouldn't be surprised if regardless of discrete cells a nasty QLCS with many embedded tornadoes (a couple maybe strong) turns out to be the big show aaand those are pretty scary; widespread wind damage and a spinup possibly practically anywhere along the line at any time with little warning makes those difficult to deal with

 

[Richardjacks]

Just doing some quick comparisons of the 500 mb charts from Super Tuesday to what the GFS/Euro are showing. First of all the upper low that cuts off in both scenarios is progged to be a bit deeper/larger for Saturday, also the position is a little further south. I can recall that day at how the dynamics and shear were just so intense that day... and they were draped over an expanding warm sector. While the capes were higher further south in Mississippi and Alabama, the dynamics further north stole the show as it max'd out the available instability, even though it was more limited compared to south.
Looking at that chart and looking at how similar dynamics will be a bit further south, plus the instability will actually be greater than some of the hardest hit areas on Super Tuesday. Basically I find this setup quite concerning, still some meso details to work out that could make or break it, but wow, overall this looks like a high-end event for Miss and Ala.

 

[Xenesthis]

Just doing some quick comparisons of the 500 mb charts from Super Tuesday to what the GFS/Euro are showing. First of all the upper low that cuts off in both scenarios is progged to be a bit deeper/larger for Saturday, also the position is a little further south. I can recall that day at how the dynamics and shear were just so intense that day... and they were draped over an expanding warm sector. While the capes were higher further south in Mississippi and Alabama, the dynamics further north stole the show as it max'd out the available instability, even though it was more limited compared to south.
Looking at that chart and looking at how similar dynamics will be a bit further south, plus the instability will actually be greater than some of the hardest hit areas on Super Tuesday. Basically I find this setup quite concerning, still some meso details to work out that could make or break it, but wow, overall this looks like a high-end event for Miss and Ala.
So you don’t think enough instability gets into the TN valley either then? Just curious because I am in southern middle TN east of Murfreesboro

 

[Kory]

Some of the shear values are off the charts for Saturday. Will we get pre-QLCS confluence bands? If we do, they will have the potential for some tornadoes. Within the QLCS, I suspect we will see some nasty embedded tornadoes...

 

[Kory]

Just doing some quick comparisons of the 500 mb charts from Super Tuesday to what the GFS/Euro are showing. First of all the upper low that cuts off in both scenarios is progged to be a bit deeper/larger for Saturday, also the position is a little further south. I can recall that day at how the dynamics and shear were just so intense that day... and they were draped over an expanding warm sector. While the capes were higher further south in Mississippi and Alabama, the dynamics further north stole the show as it max'd out the available instability, even though it was more limited compared to south.
Looking at that chart and looking at how similar dynamics will be a bit further south, plus the instability will actually be greater than some of the hardest hit areas on Super Tuesday. Basically I find this setup quite concerning, still some meso details to work out that could make or break it, but wow, overall this looks like a high-end event for Miss and Ala.

This evolution is strikingly similar to Super Tuesday 2008....

 

[Timhsv]

Found the 1st PDS sounding off the 00Z NAM. Location is just east of the Mississippi River in West Central MS....early Saturday

 

[Taylor Campbell]

I think if we keep the model trends, and akin to the EURO’s intensity, and stronger GFS ensemble solutions we are on our way to a high risk day with an expansive moderate and enhanced area; that seems to be the path we are on.

 

[Timhsv]