SluggerWx

Last two runs of the HRRR show some crazy UH tracks from Laughlin to San Antonio overnight tonight. Anyone else seeing the same thing? Sent from my Pixel 3 XL using Tapatalk

SPC AC 240600 Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 0100 AM CDT Wed Mar 24 2021 Valid 251200Z - 261200Z ...THERE IS A MODERATE RISK OF SEVERE THUNDERSTORMS OVER A LARGE PART OF MISSISSIPPI...PORTIONS OF CENTRAL AND NORTHERN ALABAMA AND ADJACENT AREAS OF WESTERN AND MIDDLE TENNESSEE... ...SUMMARY... A potential outbreak of severe storms including several long track strong tornadoes, large hail and damaging wind will exist Thursday into Thursday evening across a portion of the lower Mississippi Valley and Southeast States. ...Lower Mississippi Valley and Southeast States... Shortwave trough currently over the Southwest States will move from southern TX early Thursday through the lower MS Valley during the day and into the OH Valley overnight. Thursday morning a cold front will extend from the Great Lakes southwest to a weak surface low in northeast TX, then south into the western Gulf. In response to the ejecting negative-tilt shortwave trough, the cyclone is forecast by some models to undergo significant deepening as it develops northeast during the day. As this occurs, a cold front will accelerate through the lower MS Valley into the Southeast States, while a warm front initially from northeast TX into northern LA, central MS and southwest AL develops northward into the TN Valley. Some model differences do exist with the NAM being slightly less amplified and more progressive with resulting weaker cyclogenesis. It still appears likely that elevated storms will be in progress at the start of the period within the warm advection regime across northern MS, AL and TN. This activity is expected to continue lifting northward, allowing for destabilization from the south with time. Rich low-level moisture with upper 60s to near 70 F dewpoints will advect northward through warm sector contributing to moderate instability with up to 2000 J/kg MLCAPE. Discrete storms are expected to develop over the lower MS Valley as the surface layer destabilizes during the afternoon. The low-level jet will strengthen to 60+ kt over the lower MS and TN Valleys in response to forcing within exit region of the migratory mid-upper jet accompanying the shortwave trough. Vertical wind profiles with very strong shear and large 0-1 km hodographs (0-1 km helicity from 300-400 m2/s2) will support supercells with low-level mesocyclones capable of producing strong tornadoes and large hail. Some bowing structures are also likely. Activity will spread northeast through the lower MS and TN valleys during the day and into the evening. Additional storms may also develop along the cold front with linear structures capable of damaging wind. A secondary area of thunderstorm development might occur in vicinity of the ejecting vorticity maximum and near and just south of the surface low track from northern AR into southern MO. All hazards will be possible in this region, but threat is more conditional at this time given uncertainty regarding how much destabilization can occur. Will maintain this region in a SLGT for now, but continue to monitor for upgrade to higher probabilities in later updates. ...OH Valley... Widespread rain and thunderstorms will occur over a large part of this region during the day. However, some destabilization should occur, especially during the evening fostered by a strengthening southerly low-level jet. Potential will exist for a forced line of storms to develop along the cold front, near and south of the surface low as it tracks northeast through this region during the evening and overnight. The primary threats will be damaging wind and possibly some QLCS tornadoes. ..Dial.. 03/24/2021

Cullman and Selma cells are really intense - some of the strongest rotation we've seen today. Could be the distance from the RADAR, but they're intensifying. Edit: Cullman had a good 10 minute window but weakened - no longer warned. Sent from my Pixel 3 XL using Tapatalk

The three cells near Meridian, MS are going to be big trouble. I think we're heading into the potential long-tracker phase of this event. One of them is already warned. Almost pinpoint to the 45 hatched area on the High Outlook from SPC, too. It's kind of interesting how much tornadic activity that has already occurred - it's like the HRRR nailed the storms but lowballed UH swaths by 50%+. We could be heading for a nightmare scenario in Dixie. Heroes at NWS/SPC are going to save many lives tonight as well. Super thankful for those that chase into nightfall and the lives they may help save, too. Sent from my Pixel 3 XL using Tapatalk

That is amazing footage. Drone footage is a game changer for the Southeast will all the tall pines we have. Sent from my Pixel 3 XL using Tapatalk

Cell in far SW MS looks pretty intense. Wilkinson County, MS. Jackson livestream here: https://www.wlbt.com/2021/03/17/tornado-watch-issued-across-central-east-miss/

So much has already happened today when I didn't think we'd be discussing debris signatures until dark/after dark. It's scary to think about all this being a precursor to a stronger event within the next few hours...

There's quite a large UH swath that shows up on the HRRR after dark tonight (OK/TX border near Woodward) and tracks almost due E the whole night.

That's pretty crazy... starting on 4/27 there are like 5-6 days in a row. Of course it's la la land range, like you said, but maybe it indicates at least a potential upward trend in plains activity towards the end of April.

Next weekend and into the week of 5/20 continue to show promise for the last few days on the GFS. Sent from my Pixel XL using Tapatalk

Really cool gravity waves present on GOES-16 imagery out ahead of the line to the west of DFW. You can see a really zoomed in view here: http://weather.cod.edu/satrad/exper/?parms=local-Cen_Texas-02-200-0-100-1&checked=map Sent from my Pixel XL using Tapatalk

Last couple days the GFS is picking up on substantial instability Sunday afternoon/evening in S. KS / N. OK. It actually hinted at this area about a week ago for right around this time frame before vanishing for about 5 days. Back again.

Still a long way out, but the GFS hints at a potential midweek, multi-day threat across the plains in mid-March. Sent from my Pixel XL using Tapatalk

As recently as the 12z GFS runs yesterday, the start of June had looked pretty inactive after the insane cape values the GFS had been showing for late May. Today's model runs are the complete opposite. If the GFS continues this trend for early June over the coming days, the last 8-10 days of May and the first 4-5 days of June look to be active nearly every day on the Plains. I was trying to plan a chase trip for the 1st week of June, so I've been checking the GFS runs since early June came into range. Really interesting change over the last 48 hours for early June on the GFS.

Maybe someone should start a 5/22 - 5/30 Severe Weather Threat thread? Today's Day 7/8 outlook from the SPC indicates they are expecting a larger-scale pattern change more conducive to severe weather next week. The last few GFS runs show higher 3km EHI values for the period, but they aren't overwhelmingly being supported by high cape values. It looks like SRH/shear are contributing to the higher EHI values, which seems to have been lacking somewhat during prior periods this season. SPC's note today: DAYS 6/7 SUNDAY/MONDAY...AN INCREASINGLY SEVERE-CONDUCIVE PATTERN FOR THE PLAINS IS CURRENTLY EXPECTED AS THE WESTERN STATES TROUGH CONTINUES TO EDGE EASTWARD AND LOW-LEVEL MOISTURE TRANSITIONS NORTHWARD. SEVERE THUNDERSTORMS MAY BE POSSIBLE AS FAR NORTH AS THE DAKOTAS/MN...AND AS FAR SOUTH AS WESTERN OK/TX.

Tomorrow (5/17) already has an Enhanced Risk for Central Texas. Some crazy 3km EHI figures showing up on the NAM 4K at 00z.

Tuesday and Wednesday of next week show extremely high CAPE values all across the Central Plains (from the 00z GFS). And then there's the 6,000+ CAPE values it shows in central Oklahoma on Monday 5/16...

Mother's Day (Sunday, May 8) through Tuesday still look pretty interesting. A ways to go still, but I know the GFS has hints at something evolving over the plains/Arkalatex region as early as five days ago. We'll see.

Still a LONG ways out, but the GFS does show a potentially significant event over the OKC area the afternoon of Sunday, May 8. Worth monitoring in subsequent model runs.

JoMo - a year ago today a lot of us on here were worried the worst had happened after your final post as the couplet approached. Through the interwebs, we tried to track down your location to see if you were in the path, hoping to give some inclination that we had not lost one of our fellow weather fans. We feared the worst and hoped for the best. It's amazing to remember that I was combing through google maps a year ago tomorrow night trying to identify if you survived...I still can't believe that's what we were doing - looking for your location to see if it was in the worst damage path - for any sort of idea of your well-being. This likely pales in comparison to what you were going through a year ago tomorrow night - I can only try to understand through the amazing first hand account you've shared with us over the past year. JoMo Survived!! The moment first word broke that you were ok - I remember yelling out to my wife 'He's okay!' She knew exactly what I was talking about...cried a little bit at that time -out of joy/relief (I'm sorry if that's weird - maybe it is, but it was so uplifting to see that in such a moment of tragedy, this community of enthusiasts had a member that made it). I'm a grown adult man, but at that time - it was a glimmer of hope in the shroud of unspeakable tragedy we had only begun to understand. I've never met you, but I do want you to know that my thoughts and prayers were with you then, and they will continue to be with you and your fellow neighbors of Joplin as you relive this experience one year later. Glad you're alive, my friend. -Ryan

JoMo - I think Cyclone and I were the ones (along with others) doing the same google earth mapping to find your house at about 2 AM in the morning after the tornado. Someone found some old snow shots you had posted, and we were able to make an educated guess that you were slightly NW of the most intense damage path. Then, some folks had linked to a 'path' of the tornado outlined on Google Earth that took the thing right over your place. Still, we persisted that path was sligthly off. We posted some maps showing our research, and I'll delete those posts if you want me to. I remember using Google Maps and my huge high def TV on pause mode because I had a 6 hour live recording of everything that unfolded that day as they showed it on TWC. I was able to find the pool to the north of the hospital to view the damage path. It looked like everything to the north and west of the pool had less and less damage, and that's about a mile or so from where we thought your street was. Still, there was nothin' like when you finally showed up. I think even my wife was excited! Prayed for you man, many people did. I have an 'off-the-wall' theory about these super tornadoes that I literally stumbled upon at the Museum of Natural History in D.C.. I'll PM you about it this week.

JoMo...prayers for you. You'll see on the thread that late Sunday (early Monday AM) I posted some pics as Iowahawk, myself and others were trying to determine if you were in the path of the storm. Someone found pictures of snow you posted from Easternuswx, I believe, and then we were able to use Google Maps to somewhat identify your house. I'll delete any/all info I posted that you want me to delete. Thanking God that you're alright. Praying for you still as I know you're going through a very difficult time. If you can post what the 'on the ground' needs are from your point of view, maybe we can all rally here to help in some way. I'm sorry for your losses and I hope you find comfort in knowing hundreds of people you've never met have been praying for your well being for over 4 days and would have continued to do so until we could find out if you were okay.

TheWXMan... found a great read for you...http://journals.ametsoc.org/doi/pdf/10.1175/2008JAS2686.1 Agrees that windspeeds slow down with debris, but suggests kinetic energy could still be magnified. Can you take a look at that great study and let me know what you think? I think that the exponentially increasing kinetic energy within a debris field can change drastically with even the slightest uptick in the mass of each item of debris...i.e. going from a cornfield to a forrest.

I think you're 100% correct. My point was that in order to really get people thinking, historical references aren't going to hit home close enough for most Americans. That's why I sarcastically implied we should just go ahead and call it the worst tornado ever (or some super-sensational headline similar). Luckily, no royal wedding this week and TV programs are done with most finales. So, we might see sustained MSM coverage of tornadoes for at least a couple more days than normal.

Since intensity isn't the comparison (the 'EF' scale is the same in both cases), I'd call it an equally monsterish but more visibile tornado. They're ALL the same at the core with windspeeds, for instance if say Jarrell were to have precipitation and hit Northern Alabama or Central MS, it would be a much different looking tornado. Alabama is relatively flatter than Georgia and relatively even with forest density. Add trees and clay based soil...you get opacity. Light can't get through because clay and trees are being engulfed by the twister. In Jarrell the tornado ravaged a harder and less damp soil base - observed since light was easier to travel through the debris field and we saw a more 'visibile' tornado. Assuming both have the same precipitation.... My hypothesis is that and EF-5 tornado in parts of MO, AR, MS, AL, GA, TN, LA with equal windspeeds and equal precipitation would cause far more damage in those states than if the same exact tornado were to hit OK, KS, IA, TX, IN, IL. You have a higher potential for kinetic energy (KE) in a cubed foot of an AL tornado's debris field since there a higher potential for more debris to occupy that cubed foot. I would actually argue it's EXPONENTIALLY higher. When the cubed foot of KE hits a building in AL versus OK, the building in AL is sustaining a more significant impact by that cubed foot of KE. You can observe this with your blender. If you put strawberries and milk into a blender and blend them - you get a smoothie. If you put strawberries into a blender with five pieces of ice, you get a smootie - AND you observe LOUD cracking/smashing/tearing/destroying of the ice. That destruction of the ice you hear is the combined impact of each piece of ice's KE colliding with one another. Same speed, but the smoothie has a more dense debris field when you add the ice (my analogy for 'trees') with higher kinetic energy and more destructive force in a relative area.