Severe WX 2/5/2020-2/6/2020 Severe Weather

[Kory]

I think it's about time to get the thread going for Wednesday and Thursday's threat. Wednesday's threat, despite only having a marginal for most of Alabama and a slight risk confined to South AL, South MS, and Florida Panhandle, I think the threat is starting to look a bit more potent. Indications are a blocking complex will not occur as organized as originally thought/develop later after we already have ongoing supercellular convection across the warm sector.

 

[Chris3024]

New Day 2

 

[Kory]

I think another important factor will be the ongoing convection across Northern MS, TN, and North AL Wednesday morning creating a rain-cooled boundary that will sag south. Could be a focus for storms...assuming we get a clean warm sector.

Mesoscale models/CAMs are showing a cleaner warm sector than the globals with more organized supercellular convection.

 

[Kory]

Yeah, the extended 12z HRRR is bad for MS and AL tomorrow.

 

[akt1985]

Ironically, this system will hit on the anniversary of the Super Tuesday Outbreak in 2008, but farther south. Hope this severe weather episode is not as bad.

 

[Kory]

I’m getting increasingly concerned about tomorrow and the lack of a blocking complex down south leading to a more potent and well established warm sector further north. These positive tilt troughs with subtle preturbations in the WSW flow can mean long duration forcing for supercells throughout a warm sector that will be ripe. Shear vectors are darn near perpendicular to the boundary. Widespread ascent across the warm sector with confluence bands seems likely as shown on the latest 18z HRRR.

Throw in some morning convection across the TN river valley and you have boundaries for storms to focus on and enhance shear.

Of course if we get a blocking organize complex of storms that will limit thinks significantly but that is becoming increasingly unlikely...

 

[Xenesthis]

I’m getting increasingly concerned about tomorrow and the lack of a blocking complex down south leading to a more potent and well established warm sector further north. These positive tilt troughs with subtle preturbations in the WSW flow can mean long duration forcing for supercells throughout a warm sector that will be ripe. Shear vectors are darn near perpendicular to the boundary. Widespread ascent across the warm sector with confluence bands seems likely as shown on the latest 18z HRRR.

Throw in some morning convection across the TN river valley and you have boundaries for storms to focus on and enhance shear.

Of course if we get a blocking organize complex of storms that will limit thinks significantly but that is becoming increasingly unlikely...

Do you think this stays in AL/MS or do I need to watch this in TN? Reason I ask is because to me it looks like it stays confined to AL/MS. Just wanted your thoughts..

 

[GA Stormchaser]

A complex forecast for sure, and that point is articulated well in the BHM afternoon AFD (pretty long). Key factors won't be known for sure until the day of the event, and those have big impacts on the forecast and there may be multiple waves of strong to severe storms with a potential lull in the middle. Kory hit on some of the main points already.

 

[Kory]

00z runs are back to a messier warm sector. I think we’re still looking at a set up where we could get a few overperfoming storms. But after going bonkers, the CAMs are looking a bit more tempered with the extent of the warm sector.

 

[warneagle]

The HRRR still seems to think there's a chance for some semi-discrete cells early despite the messy warm sector, but the 3km NAM has a lot more junk convection along the coast in the afternoon which might nip that in the bud.

As always though, only takes one healthy storm in the wrong place.

 

[Justin Hindman]

Anything can happen, but looks like the convection should hamper much instability making it further than Montgomery. Have to watch the storms that form later around 10pm

 

[warneagle]

Day 2 ENH.

 

[Kory]

This event is a pain in the rear. Newest guidance suggest little coastal interference later today. This is what happens when you get a long wave trough with very tiny disturbances. Hard to pinpoint. Just be weather aware later today for some isolated to scattered severe storms.

 

[Kory]

Even some scattered convection down south won’t inhibit this. We already have the atmosphere in place and aren’t relying on strong warm air advection. It’s when you get cold pool driven complexes that muck up the warm sector.

 

[TCLwx]

Even some scattered convection down south won’t inhibit this. We already have the atmosphere in place and aren’t relying on strong warm air advection. It’s when you get cold pool driven complexes that muck up the warm sector.

67F with 65.3F Td at 7:00a.m. in TCL. It's juicy outside for Feb. 5.

 

[Kory]

67F with 65.3F Td at 7:00a.m. in TCL. It's juicy outside for Feb. 5.

I checked your station when I got up. Lol.

Anyway upgrade possible later. From the SPC:

Effective-shear magnitudes of 50-60 kt and
200-400 J/kg effective SRH should be rather common, which would
support tornado threats with any sustained/discrete cells, and
conditionally, significant-tornado potential given the parameter
space involved. Some subset of this broad risk area may be upgraded
once 12Z+ progs have arrived, and mesoscale trends become more
certain.

 

[Kory]

We’re going to have a few distinct boundaries around today. It’s why we’re seeing UH streaks across the same areas. These waves of rain this morning aren’t working over the atmosphere completely but are laying down critical boundaries that will enhance helicity later today.

 

[TCLwx]

I checked your station when I got up. Lol.

Anyway upgrade possible later. From the SPC:

Glad you are getting some use out of it. Days like today are why I got it. HRRR was printing PDS TOR soundings for TCL this afternoon. I know not to hang my hat on that, but...

 

[CheeselandSkies]

13Z HRRR is suggesting a nasty pair of sups on parallel tracks raking through MS, possibly reaching west-central AL. Similar to 12/16/19 only a bit further north.

 

[Bama Ravens]

Does the HRRR over do SB Cape? It has cape values of 1000+ j/kg all the way up into the TN Valley this afternoon/evening.