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Xenesthis
Guest
Yes the SPC has left the door wide open for an upgrade
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Archive March 18-20th, 2018 Severe Weather
- Thread starter Taylor Campbell
- Start date
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- Tags
- severe weather
Yes the SPC has left the door wide open for an upgrade
chaser
Member
- Messages
- 16
- Location
- Haleyville, Alabama
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Xenesthis
Guest
I wouldn’t be surprised to see an area of moderate let alone enhanced. It really just depends on what model comes closest to verifying.
chaser
Member
- Messages
- 16
- Location
- Haleyville, Alabama
That's true if we get any cloud breaks things could quickly explode..
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chaser
Member
- Messages
- 16
- Location
- Haleyville, Alabama
Yea I think the rule of pds..watch would be the rule Monday..
Sent from my H1611 using Tapatalk
- Messages
- 1,411
- Location
- Atop Red Mountain Birmingham, Al
Haven't had time to look at details but it appears the 12z name is slightly backing off low level shear on 12z run.
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Xenesthis
Guest
Enough to make a large difference? Last NAM guidance had a PDS TOR reading for my area
Kory
Member
- Messages
- 4,928
- Location
- Tuscaloosa, Alabama
I’m not fully confident on the tornado threat with this system just yet. It’s still very uncertain.
- Messages
- 1,411
- Location
- Atop Red Mountain Birmingham, Al
I think there will be a tornado threat, just now sure how significant.
- Messages
- 884
- Location
- Florence, AL
Some of it is with feedback from a surface low that magically develops much further east in middle TN by afternoon... previous runs had been doing this too. The NAM looks like it is trending toward correcting this, though. But even with that the case, the 12z run of the 3 km NAM... which uses the 12km for its synoptics... is doing this... WITH the south-southwest to south surface winds and the feedback issues with the low...
And the forecast soundings with the virtual temperature correction to the thermodynamic profile then show 1 km EHIs that are as high as 5-6 near Birmingham...
....along with the sickle hodographs that have the rightward kink in the lowest 1 kilometer...
The 3 km has also, since it has gotten within range the past couple of runs, had a 50 kt 850mb jet from 18Z Monday onward.
SREF might peak your interest also. 70% chance that the STP exceeds 3. 30-49.999% percent chance it exceeds 5...
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Xenesthis
Guest
How do you feel about the lower middle TN area in general?
- Messages
- 1,411
- Location
- Atop Red Mountain Birmingham, Al
Thanks Fred, I wish had more time today to look closer...maybe later this afternoon I will...not looking good.Some of it is with feedback from a surface low that magically develops much further east in middle TN by afternoon... previous runs had been doing this too. The NAM looks like it is trending toward correcting this, though. But even with that the case, the 12z run of the 3 km NAM... which uses the 12km for its synoptics... is doing this... WITH the south-southwest to south surface winds and the feedback issues with the low...
And the forecast soundings with the virtual temperature correction to the thermodynamic profile then show 1 km EHIs that are as high as 5-6 near Birmingham...
....along with the sickle hodographs that have the rightward kink in the lowest 1 kilometer...
The 3 km has also, since it has gotten within range the past couple of runs, had a 50 kt 850mb jet from 18Z Monday onward.
SREF might peak your interest also. 70% chance that the STP exceeds 3. 30-49.999% percent chance it exceeds 5...
MikeP
Member
- Messages
- 339
- Location
- Crestwood South, Bham
The hail threat seems substantial.....
- Messages
- 884
- Location
- Florence, AL
Yep, even if a tornado threat doesn't materialize, I wouldn't be shocked at an Enhanced or even Moderate Risk... because of the potential for multiple storms with very large hail... possibly up to 3 inches in diameter.
- Messages
- 1,411
- Location
- Atop Red Mountain Birmingham, Al
The differences in the 500mb flow between the nam and GFS remain substantial. Hopefully there will be better agreement later today.
tennessee storm chaser
Member
as a storm chaser... and big time severe weather lover.... finding it hard to get excited with this one....
Kory
Member
- Messages
- 4,928
- Location
- Tuscaloosa, Alabama
I'm just going to clarify...this event will not Forecasted Convective Amplification Deficiency because of the MCS, which models have pushing through Central Alabama between 12-4am Monday morning. It wouldn't surprise me to see a severe wx threat out of that as well.
Really, it is going to come down to the surface to 850mb winds. Those will make or break the tornado threat.
Really, it is going to come down to the surface to 850mb winds. Those will make or break the tornado threat.
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rolltide_130
Member
The 18z NAM run definitely trended more impressive than the 12z run did.. this is going back in the other direction.
Near Huntsville..
Near Huntsville..
- Messages
- 1,411
- Location
- Atop Red Mountain Birmingham, Al
Yes, the 18nam has trended worse, especially for north and east Al...will be interesting to see if the trend continues. Very concerning look there.The 18z NAM run definitely trended more impressive than the 12z run did.. this is going back in the other direction.
Near Huntsville..
CheeselandSkies
Member
- Messages
- 3,851
- Location
- Madison, WI
Idk if you can call a change from one run to the next a "trend," more like typical run to run variability. I'd really need to see the globals slow the system down a bit and get more in line with the NAM's synoptics.