Superstorm93 Posted April 12, 2019 Share Posted April 12, 2019 Some lingering questions about the tornado risk remain due in part to some conditional factors yet to occur. However, it appears the tornado risk may maximize in 2 corridors. First, a diurnally focused tornado risk (primarily supercellular) across northern LA into far southern AR vicinity between 3-9pm. A second area of potential concern may focus from northeast LA near the MS River east-northeast across central and into parts of northeast/east MS during the evening into the overnight. A mix mode of supercell/QLCS or hybridization of the two within a convective line are possible. Along with damaging gusts, strong tornadoes may also occur with a few of the most intense storms. While the pre-frontal, cellular convection should diminish overnight, a semi-organized band of storms -- with embedded rotating updrafts and continued severe/tornado potential -- will move across the central Gulf Coast states through the end of the period. Link to comment Share on other sites More sharing options...
vman722 Posted April 12, 2019 Share Posted April 12, 2019 Wow is all I can say pulling these soundings on the latest HRRR around 19z. Really hope those discreet cells grow upscale quickly... Link to comment Share on other sites More sharing options...
canderson Posted April 12, 2019 Share Posted April 12, 2019 I grew up here (NE Texas) but moved away in 2006. The public hype for tomorrow is nothing I’ve seen here. I’m here for a wedding that’s at 4 p.m. Saturday. It’s outdoors. lol 1 Link to comment Share on other sites More sharing options...
wotan Posted April 12, 2019 Share Posted April 12, 2019 18 minutes ago, canderson said: I grew up here (NE Texas) but moved away in 2006. The public hype for tomorrow is nothing I’ve seen here. I’m here for a wedding that’s at 4 p.m. Saturday. It’s outdoors. lol What part of NE Texas? Link to comment Share on other sites More sharing options...
canderson Posted April 12, 2019 Share Posted April 12, 2019 12 minutes ago, wotan said: What part of NE Texas? Outside Longview. Little place called White Oak. 1 Link to comment Share on other sites More sharing options...
wotan Posted April 12, 2019 Share Posted April 12, 2019 Outside Longview. Little place called White Oak. I'm vaguely familiar with the area. Haven't been up in that part of the state in a long time. Palestine is usually the furthest. Sent from my Pixel 3 XL using Tapatalk Link to comment Share on other sites More sharing options...
Indystorm Posted April 12, 2019 Share Posted April 12, 2019 Unbelievable 2 Link to comment Share on other sites More sharing options...
MattPetrulli Posted April 12, 2019 Share Posted April 12, 2019 18z HRRR still showing numerous discrete cells in Lousiana with very impressive parameters. However, cells may be a little too closely spaced for my liking, so that may be more of a concern than I originally though (I.E. 4/2/17). Still am expecting multiple siggys, but this shouldn't be ignored. HRRR's resolution also may be inflating storm size a little bit too. 2 Link to comment Share on other sites More sharing options...
Radtechwxman Posted April 12, 2019 Share Posted April 12, 2019 Yea I'm getting flashbacks of 4-2-17 with this. Very impressive parameters but not enough cap to prevent widespread storms from going up. Imo this looks to be very messy and in terrible terrain. I do think there could still be significant tornadoes but they're going to be tough to see 2 Link to comment Share on other sites More sharing options...
Southern stream Posted April 12, 2019 Share Posted April 12, 2019 Cell interference is what I was first and foremost seeing as the biggest negative with this. Even if storms congeal early on, there should be a very high damaging wind threat. Possibly derecho from LA into MS? 1 Link to comment Share on other sites More sharing options...
jpeters3 Posted April 12, 2019 Share Posted April 12, 2019 I'm not convinced that cell interference will be a problem. Firstly, 4-2-17 had slightly weaker deep-layer and low-level shear. The shear magnitudes in these profiles are more akin to 4-27-11. Remember that day didn't have much of a CAPE either, but cells stayed discrete. Stronger deep-layer shear and substantial boundary-perpendicular deep-layer shear should keep things discrete, IMO. 1 Link to comment Share on other sites More sharing options...
Superstorm93 Posted April 12, 2019 Share Posted April 12, 2019 I do agree that overall storm mode is still somewhat questionable for tomorrow, but the magnitude of effective shear we have available is pretty astounding. Even if things congeal a little too quickly during the course of the afternoon, we'll definitely have to watch for embedded strong mesocyclones. Just the thought of rain-wrapped tors with already poor visibility is pretty unnerving. (The overlay feature on weathernerds is pretty awesome by the way) 2 Link to comment Share on other sites More sharing options...
jpeters3 Posted April 12, 2019 Share Posted April 12, 2019 1 hour ago, Superstorm93 said: I do agree that overall storm mode is still somewhat questionable for tomorrow, but the magnitude of effective shear we have available is pretty astounding. Even if things congeal a little too quickly during the course of the afternoon, we'll definitely have to watch for embedded strong mesocyclones. Just the thought of rain-wrapped tors with already poor visibility is pretty unnerving. (The overlay feature on weathernerds is pretty awesome by the way) Also good to remember that while 3 km models are commonly referred to as "convection resolving" or "convection allowing," they do not have sufficient resolution to properly portray many attributes of convection. For instance, typical supercell updrafts are on the order of 8-12 km wide. A 3 km model will only have a few grid points across the extent of an updraft. The result of this insufficient resolution is that 3-4 km models tend to produce updrafts and storms that are unrealistically large, and may "unfairly" show more connection/congealment between cells during events like this. Given the magnitude of the deep-layer shear and what we know about supercell dynamics, what has happened in past similar events, and the fact that there isn't strong synoptic scale forcing overriding the warm sector, I would bet money that we see something more like widespread scattered supercells rather than a QLCS with embedded circulations. 4 Link to comment Share on other sites More sharing options...
nrgjeff Posted April 12, 2019 Share Posted April 12, 2019 Agree. It'll stay discrete longer than progged. Also could be more spacing. Finally, even if morning stuff conceals, it could actually break up again in the afternoon. Happened before plenty of times these shear profiles. 1 Link to comment Share on other sites More sharing options...
MoistWx Posted April 13, 2019 Share Posted April 13, 2019 Last couple of HRRR runs want to push an isolated cell through Central LA overnight with the warm front retreating north. Cant think this would really cause too many problems with the overall environment... But wonder if it could leave some remnant mesoscale boundaries that could persist until initiation time tomorrow. Link to comment Share on other sites More sharing options...
MattPetrulli Posted April 13, 2019 Share Posted April 13, 2019 HRRR uptrends from 18z, has a tornado outbreak across much of LA with a lot of discreteness continuing into MS overnight Link to comment Share on other sites More sharing options...
TellicoWx Posted April 13, 2019 Share Posted April 13, 2019 Not often does Sharpy trigger a PDS TOR over the southern Smokies. 00z NAM Link to comment Share on other sites More sharing options...
wotan Posted April 13, 2019 Share Posted April 13, 2019 Worth nothing that WFO Birmingham has their entire CWA under an enhanced risk, contrary to what SPC has. Sent from my Pixel 3 XL using Tapatalk Link to comment Share on other sites More sharing options...
TellicoWx Posted April 13, 2019 Share Posted April 13, 2019 Just now, wotan said: Worth nothing that WFO Birmingham has their entire CWA under an enhanced risk, contrary to what SPC has. Sent from my Pixel 3 XL using Tapatalk 00z NAM Sharpy triggered PDS TOR over Birmingham this run Link to comment Share on other sites More sharing options...
wotan Posted April 13, 2019 Share Posted April 13, 2019 00z NAM Sharpy triggered PDS TOR over Birmingham this runIt's Palm Sunday. Sent from my Pixel 3 XL using Tapatalk Link to comment Share on other sites More sharing options...
andyhb Posted April 13, 2019 Author Share Posted April 13, 2019 Not to be overdramatic, but that 00z HRRR run is quite possibly the most dangerous looking solution I've seen from that model since maybe 4/27-28/2014, and possibly even back to 2011. The number of supercells it has interacting with an extremely favorable low level environment is pretty unreal. It's not alone in upticking the apparent threat at 00z, either. Taken face value, we're easily looking at a high risk setup, but I can definitely understand if SPC wants to delay an upgrade until the situation is more certain tomorrow morning in case any convection decides to blow up on the warm front potentially limiting its movement north (but, at the same time, I could very easily see one at 06z). 8 Link to comment Share on other sites More sharing options...
Superstorm93 Posted April 13, 2019 Share Posted April 13, 2019 Shame that the HRRR-TLE tornado probs aren't being run for this event (yet) The SSCRAM+HRRR SWG has things starting to kick off pretty early AOA 14z over TX tomorrow morning https://www.spc.noaa.gov/exper/hrrr/sscram/ Link to comment Share on other sites More sharing options...
wotan Posted April 13, 2019 Share Posted April 13, 2019 Not to be overdramatic, but that 00z HRRR run is quite possibly the most dangerous looking solution I've seen from that model since maybe 4/27-28/2014, and possibly even back to 2011. The number of supercells it has interacting with an extremely favorable low level environment is pretty unreal. It's not alone in upticking the apparent threat at 00z, either. Taken face value, we're easily looking at a high risk setup, but I can definitely understand if SPC wants to delay an upgrade until the situation is more certain tomorrow morning in case any convection decides to blow up on the warm front potentially limiting its movement north (but, at the same time, I could very easily see one at 06z).You certainly aren't alone in thinking it's been awhile since we've seen something like this. Sent from my Pixel 3 XL using Tapatalk Link to comment Share on other sites More sharing options...
1900hurricane Posted April 13, 2019 Share Posted April 13, 2019 Anything that goes up early along I-45 is going to have just about the same type of volatile parameter space seen in Louisiana in the afternoon. The 00Z HRRR actually takes a UH streak over my apartment between 14-15Z. Link to comment Share on other sites More sharing options...
wotan Posted April 13, 2019 Share Posted April 13, 2019 Anything that goes up early along I-45 is going to have just about the same type of volatile parameter space seen in Louisiana in the afternoon. The 00Z HRRR actually takes a UH streak over my apartment between 14-15Z.I'm near the boundary between the marginal and slight risk areas (Fort Bend county). TWC showed some graphics earlier that had stuff at least somewhat close in the morning. I'm still trying to decide if I'm going to the Hill Country for the day. I'd be getting on the road during roughly the highest risk for us. Sent from my Pixel 3 XL using Tapatalk Link to comment Share on other sites More sharing options...
Superstorm93 Posted April 13, 2019 Share Posted April 13, 2019 00z HREF Link to comment Share on other sites More sharing options...
yoda Posted April 13, 2019 Share Posted April 13, 2019 Just now, Superstorm93 said: 00z HREF Do you have a link to that? That doesn't look good at all Link to comment Share on other sites More sharing options...
Superstorm93 Posted April 13, 2019 Share Posted April 13, 2019 Just now, yoda said: Do you have a link to that? That doesn't look good at all Sure https://www.spc.noaa.gov/exper/href/?model=href&product=ud_004hmax_pb20§or=sp&rd=20190413&rt=0000 1 Link to comment Share on other sites More sharing options...
1900hurricane Posted April 13, 2019 Share Posted April 13, 2019 Just now, yoda said: Do you have a link to that? That doesn't look good at all That's the SPC's HREF page. You can get there from the main SPC page through the Forecast Tools menu. Alternatively, here's the link. https://www.spc.noaa.gov/exper/href/ 1 Link to comment Share on other sites More sharing options...
wotan Posted April 13, 2019 Share Posted April 13, 2019 Huhhttps://www.spc.noaa.gov/products/md/md0310.htmlSent from my Pixel 3 XL using Tapatalk Link to comment Share on other sites More sharing options...
Recommended Posts
Create an account or sign in to comment
You need to be a member in order to leave a comment
Create an account
Sign up for a new account in our community. It's easy!
Register a new accountSign in
Already have an account? Sign in here.
Sign In Now