• Hello, please take a minute to check out our awesome content, contributed by the wonderful members of our community. We hope you'll add your own thoughts and opinions by making a free account!

Severe Severe weather threat April 17-19

Jessy89 said:
The nam at least has it weakening as it moves east


Sent from my iPhone using Tapatalk
Click to expand...
The nam doesn't show that, its out of the forecast range. It shows it forming over west alabama and then goes out of forecast range from close range models. Still looks to hold as a derecho well into georgia, or becoming a squall line at least.
 
Last edited by a moderator:
Rick said:
Brad travis just said one model was showing more CAPE and highs in the 80s here in Alabama but yet instability is low ???
Click to expand...
Might be, instability may be higher than what the Nam shows.
 
Arcc said:
Verbatim the NAM is a thin, thunderless squall line with the slight possibilty of marginal damaging wind and/or weak spin up tornadoes. Very much more like a fall system than spring.
Click to expand...
Are you talking about when it moves east? Or when its in alabama?
 
Gfs does something interesting. The Low pressure is in North Carolina compared to the Great Lakes like the fv3 has it.
edb365e7a8a99a1fe10465ea9afe1770.jpg



Sent from my iPhone using Tapatalk
 
Synoptically, the low track is generally where it needs to be to produce severe weather here, only issue with getting tornadoes specifically is the shear is almost entirely speed shear w/ unidirectional southerly flow from the sfc all the way to 500mb. This leads to very long but straight hodographs, which isn't generally as favorable to either left or right moving supercells (if any are embedded within the QLCS). Unless we see profound large-scale changes, damaging winds will be the biggest threat, with marginally conducive environment to tornadoes &/or gustnadoes if we encounter a large linear segment.
 
Webberweather53 said:
Synoptically, the low track is generally where it needs to be to produce severe weather here, only issue with getting tornadoes specifically is the shear is almost entirely speed shear w/ unidirectional southerly flow from the sfc all the way to 500mb. This leads to very long but straight hodographs, which isn't generally as favorable to either left or right moving supercells (if any are embedded within the QLCS). Unless we see profound large-scale changes, damaging winds will be the biggest threat, with marginally conducive environment to tornadoes &/or gustnadoes if we encounter a large linear segment.
Click to expand...
I could see a significant straight line wind event + saturated grounds = more trees down the usual over a large area type of event
 
metwannabe said:
I could see a significant straight line wind event + saturated grounds = more trees down the usual over a large area type of event
Click to expand...
Looks like guidance wants to break the line up as it moves from the Triad eastward to 95, as usual. May just end up being a few gusty showers/heavy rain event instead of a widespread severe event here.
 
Nws of bham says this will be a similar event too sunday. And rich thomas from montgomery seems to think some supercells will form ahead of the line. The 00z euro still has a bad supercell look too it.
 
Rain Cold said:
Looks like guidance wants to break the line up as it moves from the Triad eastward to 95, as usual. May just end up being a few gusty showers/heavy rain event instead of a widespread severe event here.
Click to expand...
Maybe but I'm not sure I trust guidance with those details four days out. If the synoptics play out as it showing and that low pressure center in that location with the jet streak overhead I could see A-line making a run all the way across the state time will tell of course.

Sent from my SM-G950U using Tapatalk
 
Webberweather53 said:
Synoptically, the low track is generally where it needs to be to produce severe weather here, only issue with getting tornadoes specifically is the shear is almost entirely speed shear w/ unidirectional southerly flow from the sfc all the way to 500mb. This leads to very long but straight hodographs, which isn't generally as favorable to either left or right moving supercells (if any are embedded within the QLCS). Unless we see profound large-scale changes, damaging winds will be the biggest threat, with marginally conducive environment to tornadoes &/or gustnadoes if we encounter a large linear segment.
Click to expand...
Yeah would really need secondary low formation to back sfc winds or a nw trend in the upper level features to give more of a sw flow aloft to get into a significant tor threat

Sent from my SM-G955U using Tapatalk
 
SD said:
Yeah would really need secondary low formation to back sfc winds or a nw trend in the upper level features to give more of a sw flow aloft to get into a significant tor threat

Sent from my SM-G955U using Tapatalk
Click to expand...

Like this?

033b161c5fdf8b23f182865193bec10d.jpg



Sent from my iPhone using Tapatalk
 
BHS1975 said:
Like this?

033b161c5fdf8b23f182865193bec10d.jpg



Sent from my iPhone using Tapatalk
Click to expand...

That low pressure in sc/nc is a very interesting feature. Not sure how that affect the severe weather threat. Perhaps more of a hail threat to


Sent from my iPhone using Tapatalk
 
metwannabe said:
Maybe but I'm not sure I trust guidance with those details four days out. If the synoptics play out as it showing and that low pressure center in that location with the jet streak overhead I could see A-line making a run all the way across the state time will tell of course.

Sent from my SM-G950U using Tapatalk
Click to expand...
Yeah, we're several days out. The features will definitely change. I'm usually not a big fan of Lows running up the spine of the Apps. Usually, they end up east or west of there. We'll see where it eventually goes. Forcing ought to be pretty strong, but CAPE doesn't look overly impressive. I guess the timing isn't very good, if we're talking about the main line coming in Friday night. But as you said, it's not set in stone yet. I'm sure we'll see things change around a bit as we get closer. Either way, I am not going to fall for the eventual NAM runs that spit out 14,000 j/kg ml CAPE or the long range HRRRrrrR that shows hypergalactic supercell-induced mega-PDS 5 mile wide wedge tornadoes.
 
BHS1975 said:
Like this?

033b161c5fdf8b23f182865193bec10d.jpg



Sent from my iPhone using Tapatalk
Click to expand...

Still not anywhere near ideal but we could probably use more backing of the sfc winds and a stronger low in the lee of the apps to get tornadoes. SSE at the sfc to SSW at 500 hPa even on the LR NAM isn't amazing. If we see a stronger sfc low, thru isallobaric wind, back our sfc winds more to SE or ESE w/ the same look at 500 hPa, then we could have a huge problem on our hands in the Carolinas.
namconus_z500_vort_seus_53.png
 
Your average damaging wind sounding, wind profiles aiding in linear convection, steep 0-3km lapse rates, dry air aloft (central NC) note how CAPE isn’t impressive0874A946-6DEF-423F-909C-A58FD630A3CF.jpeg
 
Silly long range NAM...

1555430372342.png

This is a sounding that's near the SC coast. I won't dismiss this possibility if in the future, the Energy Helicity Index maps look like what they did on the 12z NAM, but right now, naaahhh. I don't exactly think so on this.
 
Webberweather53 said:
Still not anywhere near ideal but we could probably use more backing of the sfc winds and a stronger low in the lee of the apps to get tornadoes. SSE at the sfc to SSW at 500 hPa even on the LR NAM isn't amazing. If we see a stronger sfc low, thru isallobaric wind, back our sfc winds more to SE or ESE w/ the same look at 500 hPa, then we could have a huge problem on our hands in the Carolinas.
View attachment 19079
Click to expand...

at This point the threat of wind damage from these is really concerning, with so much wind energy from this system, storms just gotta tap into that aloft and drag it down with heavier showers, these storms will probably somewhat lack thunder and lightning, I don’t want any tornadoes after that close call Sunday night, even if it didn’t touch down
 
Webberweather53 said:
Still not anywhere near ideal but we could probably use more backing of the sfc winds and a stronger low in the lee of the apps to get tornadoes. SSE at the sfc to SSW at 500 hPa even on the LR NAM isn't amazing. If we see a stronger sfc low, thru isallobaric wind, back our sfc winds more to SE or ESE w/ the same look at 500 hPa, then we could have a huge problem on our hands in the Carolinas.
View attachment 19079
Click to expand...
The profile overnight Thursday into the morning friday is a little more supportive of tors. Wouldn't be completely shocking to get a couple rotating cells moving in from the Atlantic then

Sent from my SM-G955U using Tapatalk
 
SD said:
The profile overnight Thursday into the morning friday is a little more supportive of tors. Wouldn't be completely shocking to get a couple rotating cells moving in from the Atlantic then

Sent from my SM-G955U using Tapatalk
Click to expand...

Most the sounding in northern Georgia and upstate sc and western nc don’t look all that severe


Sent from my iPhone using Tapatalk
 
No joke if storms manage to fire tommorow in Texas, there’s gonna be some giant hail, like bigger than baseball size hail, monstrous hail growth zone, dry air aloft supporting hail, WBZ at 700 hPa, some 0-6km shear, chasers better be aware not to get close to the RFD or the core of any supercell tommorow
A0A91AE4-F7F6-4A49-9D20-B3DE01AEA6D5.png
 
Looks like cips severe probabilities for tornadoes are decent thursday. I think itll be more embedded supercell type tornadoes if any unless a supercell forms ahead of the line. Instability has been rising in recent runs of the nam. Nws of bham is waiting for more consistency and outcome of the secondary low/instability to put a enhanced severe risk on portions of west and southwest alabama. Screenshot_20190416-113111_Samsung Internet.jpgScreenshot_20190416-113131_Samsung Internet.jpg
 
Last edited by a moderator:
Myfrotho704_ said:
Probably because there is not much CAPE, but speed shear is so strong with this one that showers could possibly have gusty/damaging winds
Click to expand...

Yeah morehead city is thinking we see some decent winds out in front before the storms ever get here. You would think any heavy showers or storms should tap into that LLJ.

A very strong LLJ (>60 kt around 925 mb)
will develop across the area as the stacked low passes inland,
riding northward along the Appalachian chain Friday and Friday
night. LLJ winds will readily mix to the surface during the day,
bringing strong/gusty winds, especially to coastal areas. A
wind advisory or warning may be needed for at least some of the
area. From a severe weather perspective: Instability is the
question as a moist prefrontal airmass will keep skies cloudy
and there is potential for showers ahead of the primary band of
convection, both inhibiting factors for the development of
surface based instability. Still, shear is strong enough to
justify a continued slight risk of severe weather from SPC, with
damaging wind gusts the primary concern in the strongest
convection, and large hail and tornadoes also possible.
 
Someone dig up Jan 7th 1997 I think it was, there was a squall line that night that had gust 100-145 mph over parts of eastern NC that were not tornadic...I know Seymour Johnson recorded a 146 mph gust. It was bad in Greenville though nowhere near 140 lol.....New Bern hit the low 100's as well I think. Interested to see what the setup was but cant find much on this event or at least not easily.
 
Mid level flow is expected to strengthen over the Carolinas to over 100kts and LLJ over 60kts+. I've seen these types of setups produce damaging wind without convection let alone having signification convection to induce downward momentum of that kind of wind energy.

Furthermore in the Carolinas ... watch out for a discrete Piedmont Meso Low popping up. It that happens, things could explode in a hurry
 
TXTornado said:
Texas is going to get some massive hail tomorrow. Tornado threat does look minimal, but HRRR and NAM show some potential for a tail-end charlie storm to pop
Click to expand...

Wouldn’t suprise me if there’s some 3-4 inch hail reports tommorow
 
You must log in or register to reply here.
Back
Top