Jrips2710
Member
“widespread damaging winds and a few tornadoes across much of AL into western/central GA through the overnight hours. Higher wind probabilities may be needed in subsequent outlooks if confidence in this scenario grows.”
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4/11/20 - 4/13/20 Severe Weather Outbreak
- Thread starter Webberweather53
- Start date
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- Tags
- severe weather tornadoes
RollTide18
Member
Important to note from SPC as to why they didn't upgrade to high
"While the conditional risk of all severe hazards will be quite high
if supercells develop, uncertainty remains regarding how convection
will evolve from the morning into the afternoon. Any remnant outflow
related to early convection will determine the northern extent of
the higher-end tornado potential, and some guidance suggests the
potential for elevated convection within a midlevel moist plume
across the warm sector during the afternoon, which could either
dampen the severe potential, or evolve into surface-based convection
with a substantial severe threat. Given these factors, there is too
much uncertainty to upgrade the ongoing outlook at this time. "
"While the conditional risk of all severe hazards will be quite high
if supercells develop, uncertainty remains regarding how convection
will evolve from the morning into the afternoon. Any remnant outflow
related to early convection will determine the northern extent of
the higher-end tornado potential, and some guidance suggests the
potential for elevated convection within a midlevel moist plume
across the warm sector during the afternoon, which could either
dampen the severe potential, or evolve into surface-based convection
with a substantial severe threat. Given these factors, there is too
much uncertainty to upgrade the ongoing outlook at this time. "
Jrips2710
Member
06z NAM should start rolling in about 45 to an hour. Not sure what other short range stuff runs on the off hours off the top of my head.
Euro ticked slower.
Euro soundings are even scarier in around CLT, still trending up with cape towards NAM 
NWS GSP discussion 
Keldeo
Member
Last Frame of the HRRR (1:00PM CST )is looking very scary with most of the warm sector untouched. Temps in the 80s in Southern MS and CAPE values of 3K+
Claycochaser
Member
Really strong capping EML which would significantly hamper the potential for supercells out ahead of the main line. However, this would also lead to an untapped environment as the main forcing moves in thus more instability with which to work. Also another thing to consider are the shear vectors and the trend towards less of a QLCS and more a broken line of supercells in the evening which would ultimately be just as disturbing as cells in the free warm sector.
Webberweather53
Meteorologist
Even with the crappy diurnal timing and the fact that there's nothing more than a slight risk of severe in the Carolinas, I'm starting to become deeply concerned about the tor threat here Sunday Night into Monday. If the 3km NAM or ECMWF are even remotely close to being right, we're in big trouble. Keep in mind that the overwhelming majority of tornado deaths occur at night.
Webberweather53
Meteorologist
The one major critical piece for tornadoes that's been limiting in the modeling thus far in NC is CAPE, every run of the ECMWF keeps jacking it up & is trending towards the 3km NAM
Here's Apr 16 2011 as a reference:
We're basically in the same ballpark now in this regard...
I don't like this at all.
Here's Apr 16 2011 as a reference:
We're basically in the same ballpark now in this regard...
I don't like this at all.
Shaggy
Member
Mhx starting to pick a main timeframe. Mid morning to early afternoon and any delay brings it in during peak heating. We are walking a fine line and if we get this to come in after lunch time it will just have more instability to tap. For those of us east of the piedmont thats an important factor heading forward.
The strongest WAA does not get going until late Sunday night
into Monday morning when the gradient tightens locally and a
notably strong 50-60 kt LLJ moves over the area, bringing very
strong low level theta-e advection. Despite the unfavorable
diurnal timing, instability will quickly climb to 1000-1500+
J/kg early Monday with 0-6km bulk shear around 60-70 kt and
expect a line of strong QLCS thunderstorms to push across the
area through the morning into the early afternoon which will
have the capability of producing damaging wind gusts and
isolated tornadoes. Still some uncertainty with the timing as
models have been trending slower over the past couple cycles
and any additional delay will bring storms across the area
as we approach peak heating. In addition to the severe threat,
strong gradient winds may necessitate a wind advisory across
some coastal counties, a high surf advisory along the coast and
coastal flooding across portions of the sounds (see Tides/Coastal
Flooding section below for more details). Heavy rainfall will
also be possible at times, though individual storms should be
progressive enough to preclude a widespread flash flooding
threat. Conditions quickly improve Monday afternoon after the
line of storms moves offshore.
The strongest WAA does not get going until late Sunday night
into Monday morning when the gradient tightens locally and a
notably strong 50-60 kt LLJ moves over the area, bringing very
strong low level theta-e advection. Despite the unfavorable
diurnal timing, instability will quickly climb to 1000-1500+
J/kg early Monday with 0-6km bulk shear around 60-70 kt and
expect a line of strong QLCS thunderstorms to push across the
area through the morning into the early afternoon which will
have the capability of producing damaging wind gusts and
isolated tornadoes. Still some uncertainty with the timing as
models have been trending slower over the past couple cycles
and any additional delay will bring storms across the area
as we approach peak heating. In addition to the severe threat,
strong gradient winds may necessitate a wind advisory across
some coastal counties, a high surf advisory along the coast and
coastal flooding across portions of the sounds (see Tides/Coastal
Flooding section below for more details). Heavy rainfall will
also be possible at times, though individual storms should be
progressive enough to preclude a widespread flash flooding
threat. Conditions quickly improve Monday afternoon after the
line of storms moves offshore.
Wind
Hail
Tornado
The weather channel has rain all day for my area with 67 degrees .... hmm Periods of rain. Rain may be heavy late. High 69F. Winds SE at 15 to 25 mph. Chance of rain 100%. 1 to 2 inches of rain expected. Locally heavy rainfall possible. North Alabama
Last edited:
Storm5
Member
Lol what ? No they are not , Huntsville isn’t . They question how far north the instability will get in that area but that’s always been a question
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Oh ok sry just seemed like they were not as impressed this am....still lots of variables
WXinCanton
Member
Rick, deep breaths my man. lol
Storm5
Member
Very true . Hopefully things work in our favor with less instability and more junk convection. Even if that happens damaging wind will still be a big concern as this will be a very dynamic system
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Lol yeah I like tracking the weather fir the science part but it's a huge headache being a day out and not knowing too much still I am cooking today but need to get out of my place if it gets really bad here
Z
Zander98al
Guest
Updraft helicity swaths. For sunday into early monday. Lots of deiscrete updrafts. I think the prime question is how will junk convection or rain showers effect the warm sector. All the other parameters are ripe but the question remains with the rain possibly being in the warm sector which probably wont be resolved until shortly before things start rockin and rolling. 3km nam wants to show it not effecting things along with some other CAM's. ?
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