Severe Thread: 5/13-17

[JPWX]

Not a 45 contour showing up across North-Central MS on Friday.

 

[TornadoFan17]

Not a 45 contour showing up across North-Central MS on Friday.

Is there any consensus on where the main risk is yet? The SPC has south MS/LA in the D3, someone else mentioned (might have been you) to watch out for the TN valley, and now we have 45 contours over North-Central MS. This isn't me being critical, it's a genuine question: Is it really that hard to get an accurate idea of where the main threat will be 3 days in advance? Those are three pretty different areas.

 

[JPWX]

Is there any consensus on where the main risk is yet? The SPC has south MS/LA in the D3, someone else mentioned (might have been you) to watch out for the TN valley, and now we have 45 contours over North-Central MS. This isn't me being critical, it's a genuine question: Is it really that hard to get an accurate idea of where the main threat will be 3 days in advance? Those are three pretty different areas.

Well, the biggest issue is MCS potential across the Gulf Coast region that is a question as to how fast it moves out, which in turn, would lead to a greater severe potential for areas this far north. That's why SPC hasn't drawn a bigger Level 2 risk yet. You have plenty of shear and instability to work with. It's just that pesky MCS potential is the biggest question mark at this time. SPC, NWS Jackson, Birmingham, and Huntsville all mention severe weather potential

 

[Clancy]

The wind profiles are just yikes. Randomly picked sounding off the 00Z NAM in west GA. Models still disagreeing on a quite a few details, but a lot of the large-scale things are there. HRRR is perhaps most bearish with convection down south choking off instability. Hoping that's what verifies, because if not, could be a potent setup for the Southeast Friday.

 

[KevinH]

No bueno if this type of solution verifies for the Deep South. Sounding from western ATL metro.
View attachment 27159View attachment 27160

aaaaaaand now the thread has my attention lol

 

[KevinH]

The wind profiles are just yikes. Randomly picked sounding off the 00Z NAM in west GA. Models still disagreeing on a quite a few details, but a lot of the large-scale things are there. HRRR is perhaps most bearish with convection down south choking off instability. Hoping that's what verifies, because if not, could be a potent setup for the Southeast Friday.
View attachment 27163

West GA? Not me typing in those coordinates lol

UPDATE: If I input those coordinates right, that is in Buchanan, GA, directly west of Atlanta.. and north of me.

I guess it’s time to turn on notifications for this thread.

 

[Clancy]

West GA? Not me typing in those coordinates lol

UPDATE: If I input those coordinates right, that is in Buchanan, GA, directly west of Atlanta.. and north of me.

I guess it’s time to turn on notifications for this thread.

Yeah that should be about right. NAM had PDS soundings all across W GA and E AL.

 

[KevinH]

Yeah that should be about right. NAM had PDS soundings all across W GA and E AL.

Something to watch … even though the SPC hasn’t “pulled any triggers”

 

[Clancy]

Lots of questions regarding Friday and Saturday, mostly revolving around convective evolution. 2 solutions offered by CAMs, 1) coastal MCS cuts off convection up north, as suggested by WRF-NSSL and HRRR, and 2) lack of coastal activity allows for discrete development in a highly sheared warm sector, as modelled by NAM and WRF-ARW. Also possible threat again on Saturday, but that would depend heavily on how Friday pans out. Wind fields also a lot more unidirectional by that time. Will have to wait and see.

 

[KevinH]

Lots of questions regarding Friday and Saturday, mostly revolving around convective evolution. 2 solutions offered by CAMs, 1) coastal MCS cuts off convection up north, as suggested by WRF-NSSL and HRRR, and 2) lack of coastal activity allows for discrete development in a highly sheared warm sector, as modelled by NAM and WRF-ARW. Also possible threat again on Saturday, but that would depend heavily on how Friday pans out. Wind fields also a lot more unidirectional by that time. Will have to wait and see.

So in other words…????

 

[Clancy]

So in other words…????

Well, as of 12Z most of the CAMs have come in with the solution that I reckon is most likely to verify. Heavy rain will blanket most of northern AL and GA Friday afternoon, which spares the northern halves of both states from severe weather. However, areas south of there (Columbus included, sounding from nearby) would still be under threat thanks to strong instability and fairly favorable wind fields. Modelling also shows a potential 2nd threat on Saturday for the central and northern portions of MS/AL/GA, but at that point it'd be mostly a lower-end wind and hail threat. Of course, by this evening models will probably look completely different, but it aligns with how setups like these often pan out.

 

[KevinH]

Well, as of 12Z most of the CAMs have come in with the solution that I reckon is most likely to verify. Heavy rain will blanket most of northern AL and GA Friday afternoon, which spares the northern halves of both states from severe weather. However, areas south of there (Columbus included, sounding from nearby) would still be under threat thanks to strong instability and fairly favorable wind fields. Modelling also shows a potential 2nd threat on Saturday for the central and northern portions of MS/AL/GA, but at that point it'd be mostly a lower-end wind and hail threat. Of course, by this evening models will probably look completely different, but it aligns with how setups like these often pan out.
View attachment 27164View attachment 27165
View attachment 27166

D2 in a couple hours may be interesting.

 

[KevinH]

Nothing to write home about for now but….

 

[JPWX]

Day 2 really shrunk from what I had expected. That MCS potential is the biggest question mark for the severe weather risk for northern zones of the Southeast

 

[warneagle]

Potentially a major flash flooding event setting up across TX/LA. WPC issued a high risk.

 

[warneagle]

Day 2 really shrunk from what I had expected. That MCS potential is the biggest question mark for the severe weather risk for northern zones of the Southeast

Yeah that morning MCS is just gonna work the environment over, you’re not gonna get enough recovery outside of the immediate Gulf Coast for an appreciable severe threat.

 

[andyhb]

Yeah that morning MCS is just gonna work the environment over, you’re not gonna get enough recovery outside of the immediate Gulf Coast for an appreciable severe threat.

This is why we don't trust the NAM beyond 36-48 hours (if at all), everyone.

 

[KevinH]

This is why we don't trust the NAM beyond 36-48 hours (if at all), everyone.

Can we ever trust the NAM though?!

Jk jk

 

[atrainguy]

 

[Kolle]

90-100mph gusts entering downtown Houston.