Tn Valley Severe Weather

[Windspeed]

The setup for early-to-mid May could be a volatile one for strong storms for the Mississippi and Tennessee Valley. Potent shortwaves enhanced by southwesterly jet out of Mexico, cooler than normal upper levels in May, advancing dry lines out of Texas, strong bulk shear, etc.; it only takes one of those surface lows to come in line to make for a memorable event. Yes, obviously not wanting to overhype so far in advance. Yes, it's Spring and there shall be storms with increasing juicy Gulf moisture as per the norm, but the atmosphere may very well be conducive for at least one strong Southern outbreak.

 

 

[jaxjagman]

If the weeklies are anywhere right not only there would be a severe threat but a big flooding threat into wk 1 and week 2 of May.This system around  the first of May is looking better also recently,so we'll have to see what happens with this

[jaxjagman]

Maybe towards the Mid month we'll see a better system.The boundary isn't up towards the lakes but a warm front potentially could be lifting through the Valley

[jaxjagman]

The MJO also would be favorable during this time on the maps above.But where it goes after it gets into the IO is in question and how amped it will be when it does get there

[nrgjeff]

Severe weather may return to the CONUS the week of May 14. My thoughts on the current week may be in Central/West, if they stop nitpicking each other. Our sub-forum region is so much better!

MJO is forecast to return to a severe wx phase the middle of May. AAM should remain negative, another ingredient to leverage that MJO. Week 3 on both weeklies shows a new Pacific jet chipping away at the week 2 West ridge. End of Euro/Cad ensembles shows the new trough starting, GFS could be behind the curve. During week, 3 I expect a West trough and East ridge. Couple energy vendors are pretty confident about that pattern. Their concern is temperature. My concern is storms, lol!

While the Plains dry line may be active the week of May 14, it's one of those deals where the warm front could be active well to the east, into our Tennessee Valley or Ohio Valley. Mid-May is the season for both to go at once.

[jaxjagman]

On 4/22/2018 at 3:15 AM, jaxjagman said:

 If  the BSR map is correct we could be looking at the potential for some good storms into week 2 of May.The Dashboard is all over this time frame.Along with the BSR maps shows a area of LP coming out of Texas into the Valley.The OLR has been showing up on this time frame as well.We'll see

 

 

Keep a eye on this time frame.The MJO has been showing signs of being LESS progressive as it was being shown getting into the IO into week 2 now more mid month,either way

[nrgjeff]

I want to be bullish, but we can't even muster a Maginal today May 5. NWP verbatin wind fields are a mess Friday; but, it is May! If all else fails, Go Preds!

[jaxjagman]

6 hours ago, nrgjeff said:

I want to be bullish, but we can't even muster a Maginal today May 5. NWP verbatin wind fields are a mess Friday; but, it is May! If all else fails, Go Preds!

Agreed.But still need to watch next Wed and maybe Thursday especially during diurnal heating.GFS last run shows some better Super cell composites with better bulk sheer Wednesday in the Western Valley.Difference to me between the Euro and GFS is the GFS shows a shortwave in the western Valley,the Euro don't show this.So who knows which will cave.Also going to Thursday if the GFS  is right,shows MUCapes of around 3.7K in portions of the eastern Vallley

 

[nrgjeff]

My money is always on the Euro, but you know that. GFS can and does occasionally score coups though. 12Z Sunday GFS dropped all the wind shear but it could come back. Also I do not do indices that far out. Just looking at mandatory level charts (850/700/500/250). Turning is still there, considering WNW at 500 the SSW 850 would work. However speeds are totally AWOL. Still a few days out and CAPE will be there. We'll hope!

PS. not trying to debate. I'm just watching like a hawk because my interests farther west keep getting delayed. Sigh...

If I'm wrong, we can go chasing, Quincy too, and I'll pay all fuel.

[Quincy]

27 minutes ago, nrgjeff said:

My money is always on the Euro, but you know that. GFS can and does occasionally score coups though. 12Z Sunday GFS dropped all the wind shear but it could come back. Also I do not do indices that far out. Just looking at mandatory level charts (850/700/500/250). Turning is still there, considering WNW at 500 the SSW 850 would work. However speeds are totally AWOL. Still a few days out and CAPE will be there. We'll hope!

PS. not trying to debate. I'm just watching like a hawk because my interests farther west keep getting delayed. Sigh...

If I'm wrong, we can go chasing, and I'll pay all fuel.

I haven't really looked into Thursday that much, but Wednesday has my attention, especially for areas closer to the Mississippi River. Still waiting on the 12z Euro to come into range, but I did notice that the last few runs of the Euro flip-flopped around with positioning and strengths of the wind fields. The overall sign is there for at least a marginal severe setup, given flow aloft and boundary layer moisture. It's still a few days out, so details are cloudy, but it is May and May is starting to look more interesting, especially in the longer range...

[jaxjagman]

We had a little hail this afternoon in the Middle Valley, some big cumulus clouds,this was from Fairview.The cells started to weaken by the time they got to us ,we saw some but nothing like this

 

 

[jaxjagman]

21 hours ago, nrgjeff said:

My money is always on the Euro, but you know that. GFS can and does occasionally score coups though. 12Z Sunday GFS dropped all the wind shear but it could come back. Also I do not do indices that far out. Just looking at mandatory level charts (850/700/500/250). Turning is still there, considering WNW at 500 the SSW 850 would work. However speeds are totally AWOL. Still a few days out and CAPE will be there. We'll hope!

PS. not trying to debate. I'm just watching like a hawk because my interests farther west keep getting delayed. Sigh...

If I'm wrong, we can go chasing, Quincy too, and I'll pay all fuel.

Yeah, the MJO is taking  it's time seemingly getting out of Africa into the IO,than what's been modeled.

Wednesday,the GFS recently the last couple runs have backed off the sheer in the west, CPC has nothing but a marginal risk .Euro don't still show a whole heck of alot of anything like you mentioned.Should be a better chance starting around mid month and beyond.Certainly  with the MJO  and the recent SOI crash it would seem that way anyways with a system into the 3rd week of May.If the BSR maps are close to anything right there would be a CF coming towards the Valley then stalling out.We'll see

[nrgjeff]

Weeklies are starting to go that direction, a system digging into our region around mid-May. CFS hints; Euro due at 22:15Z. Whether wind shear and stability line up is a whole other set of questions. On the surface that's exciting news close to home, but it's a mess in the Plains. 

Short-term, Wednesday Illinois might have enough turning with height if morning storms leave and outflow and instability can return. Probably be messy though. Plus the Marginal into our neck of the woods is the hilly lush jungle of dueling banjos. Flat Delta looks too far west.

[jaxjagman]

SOI recently has taken  some big swings.Wednesday looks questionable but both the GFS and Euro has a shortwave coming through Middle TN in the afternoon,so if something does pop it could get severe.GFS also shows some better bulk sheer tonight.Soundings just west of Nashville

Edit:Euro still looks pathetic on the OZ

 

Date	Tahiti (hPa)	Darwin (hPa)	Daily Contribution	30 day Av. SOI	90 day Av. SOI
8 May 2018	1014.56	1011.85	9.06	-2.94	3.12
7 May 2018	1013.35	1013.75	-14.77	-2.93	2.71
6 May 2018	1013.17	1014.85	-24.57	-1.88	2.57
5 May 2018	1013.09	1013.65	-15.99	-0.39	2.62
4 May 2018	1014.37	1012.50	2.62	0.85	2.55

[nrgjeff]

Next week looks more interesting, although forecast wind fields are currently pathetic. Might have a stationary boundary nearby with plenty of CAPE. Later into the season high CAPE can get things going, just the opposite of early season shear. If wind fields could strengthen just a bit, next week would be interesting. Heat ridge nearby makes winds a challenge.

One or two days that go from the Plains all the way over here would not shock me. Tis the season in late May.

[jaxjagman]

Some signs of a wet June in the Valley.NMME and RRWT is showing it

[nrgjeff]

Euro / ECMWF Monthlies look like that all summer. From the June 500 mb pattern I infer fronts (and hopefully late-season severe). July-August looks more like coming in underneath from the Gulf/Southeast Coast. Well, August 500 could be either but climo says underneath. Desert Southwest monsoon is also forecast robust. Relevance here is if easterly waves are juicy too. If things look the same by Memorial Day maybe I will write more in the Seasonal thread. Cheers!

[jaxjagman]

The Valley looks fairly active through out the month of June, per the Dashboard.We should see a chance of thunderstorms pop back up Friday as the Upper ridge weakens and shifts east,then we'll see what or if the system in the GOM brings someone next week.

[nrgjeff]

If a subtropical system can gin up 850/925 mb winds the Region would have a better chance of actual severe early next week. Odds may be higher Deep South. May 2018 is strange...

[jaxjagman]

System going through Korea in the end of the month,PNA is going - while the NAO is up in the air and could go negative(not what we want,this would suppress the storm),if the NAO stays more neutral/positive we could see a decent system towards the end of the 1st week of June,we'll see

[rolltide_130]

Don't rule out a severe threat for the first few days of June - GFS has been holding the idea and some of the thermos are flat out riduclious for Dixie Alley. Shear is meh but if some of the CAPE profiles verify, it may not matter much especially with the SE motion that seems likely. 

[jaxjagman]

2 hours ago, rolltide_130 said:

Don't rule out a severe threat for the first few days of June - GFS has been holding the idea and some of the thermos are flat out riduclious for Dixie Alley. Shear is meh but if some of the CAPE profiles verify, it may not matter much especially with the SE motion that seems likely. 

Nice catch.I believe we are talking about the same system but i'm slower than what the models are showing or the models are fast,we shall see.Yesterday the the AO was being shown going negative and today it's being shown slightly positive with still a -PNA,less suppressed system

[Carvers Gap]

7 hours ago, rolltide_130 said:

Don't rule out a severe threat for the first few days of June - GFS has been holding the idea and some of the thermos are flat out riduclious for Dixie Alley. Shear is meh but if some of the CAPE profiles verify, it may not matter much especially with the SE motion that seems likely. 

Thanks, roll tide.  Good info!

[jaxjagman]

Alberto got relocated further east today/tonight,so the storm is being shown further east on tonight's models,yeah that's how i feel..lol.The better winds are now being shown to the east of Middle Valley ,east of I-65 anyways,maybe more towards the plateau,but better potential flooding for us as it looks the system could go over Nashville right now,per GFS and NAM

[jaxjagman]

Euro continues this pathetic severe season in the Valley,we can't even get a tropical system to produce..lol

[jaxjagman]

Day 2 Convective Outlook  
   NWS Storm Prediction Center Norman OK
   0100 AM CDT Wed May 30 2018

   Valid 311200Z - 011200Z

   ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS OVER A PORTION OF
   THE LOWER MISSISSIPPI...TENNESSEE AND OHIO VALLEYS AS WELL AS THE
   NORTHERN HIGH PLAINS...

   ...SUMMARY...
   Isolated to widely scattered severe thunderstorms remain possible
   Thursday from the Missouri Ozarks to the lower Ohio Valley and
   Tennessee Valleys as well as the northern High Plains.

   ...Synopsis...

   Synoptic trough will advance through the Great Lakes and OH Valley
   Thursday. A low-amplitude shortwave trough now approaching southern
   AZ will reach the middle MS Valley 12Z Thursday before continuing
   through the southern portion of the OH Valley during the day.
   Farther west a high-amplitude upper trough will move through the
   western states. At the start of the period a weak cold front should
   extend from the Great Lakes into the upper MS Valley and central
   Plains. A quasi-stationary/warm front will extend from a weak low in
   northwest TX through OK and the lower MS Valley, while dryline
   persists across west TX. Farther north a cold front will extend from
   the High Plains of MT through the northern Rockies.

   ...Southern MO through KY and TN...

   In the wake of Alberto, 70F dewpoints will reside in the warm
   sector. Meanwhile, an increase in westerly trajectories will
   contribute to eastward expansion of the elevated mixed layer through
   the lower MS and western portion of TN Valley above the very moist
   boundary layer. These processes and expected diabatic warming should
   result in moderate to strong instability with MLCAPE from 2000-2500
   J/kg during the afternoon. Storms may be ongoing in association with
   progressive, low-amplitude shortwave trough from OK into southeast
   KS and southwest MO. Evolution of the early storms is uncertain, but
   new development and or intensification of additional storms along
   associated outflow boundaries may occur as the downstream atmosphere
   destabilizes. An increase in flow through the mid-levels
   accompanying the shortwave trough will contribute to 30-40 kt
   effective bulk shear supportive of some organized storm structures,
   including bowing segments with damaging wind and hail the primary
   threats from afternoon into the evening.

[nrgjeff]

Monday I busted in South Georgia. Tuesday the best storm came right over my house by about 02Z Wed. We had nice lightning and thunder with torrential rain. Too bad no hail in tropical precip.

Thursday nice mid-level winds and short-wave are forecast. Regrettably 850/925 mb is terribly veered. I know Dixie can give a little compared to the Plains, but this is a deal killer. 2018, sigh. Actually Kentucky should get severe, but probably wind/hail.

[jaxjagman]

Day 2 Convective Outlook  
   NWS Storm Prediction Center Norman OK
   1230 PM CDT Wed May 30 2018

   Valid 311200Z - 011200Z

   ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS THE
   MONTANA/WESTERN NORTH DAKOTA VICINITY...AS WELL AS THE MID
   MISSISSIPPI...LOWER OHIO...AND TENNESSEE VALLEYS AND SURROUNDING
   AREAS...

   ...SUMMARY...
   Isolated to widely scattered severe thunderstorms remain possible
   Thursday from the Missouri Ozarks to the lower Ohio Valley and
   Tennessee Valleys as well as the northern High Plains and northern
   Rockies.

   ...Synopsis...
   A large upper trough near the West Coast at the start of the period
   is progged to advance slowly eastward toward the Intermountain West.
    Meanwhile, a smaller/shorter-wavelength trough will shift east
   across the Upper Great Lakes and Midwest regions and vicinity.

   At the surface, a cold front will progress slowly across the
   Intermountain West ahead of the western trough, while a
   second/weaker front crosses the Great Lakes region.  Weaker
   troughing/low pressure -- enhanced by convective outflows -- is also
   expected to linger in a west-to-east zone from the Kansas/Oklahoma
   area into the lower Ohio Valley area.

   ...The Ozarks into the Ohio and Tennessee Valleys...
   While the background environment across the region appears favorable
   for development of organized/severe storms Thursday, a somewhat
   complex/uncertain evolution of convective risk is evident -- largely
   due to overnight/late Day 1 convection which should be moving out of
   the Oklahoma/Kansas area across the Ozarks/southern Missouri
   vicinity.  Models differ with respect to how widespread/organized
   the lingering convection is likely to be, and thus locations of
   associated convective outflows and associated cloud cover.  In
   addition, some guidance suggests re-intensification of this
   convection early in the day as it crosses the Tennessee Valley
   vicinity, prior to the main round storms expected to develop later
   in the day.  

   Given the uncertainties regarding early convective evolution and the
   effects on timing/location of subsequent development, will maintain
   15%/SLGT risk across the region.  As Day 1 convective evolution
   becomes more clear, an upgraded corridor of enhanced risk for
   Thursday may become necessary, as afternoon destabilization of the
   moist boundary layer away from convectively contaminated areas
   combined with enhanced mid-level westerlies associated with the
   advancing short-wave trough will result in an environment favorable
   for organized/severe storms.

   In general, loose agreement amongst various models suggests
   afternoon storm redevelopment over the vicinity of the Mid
   Mississippi/Lower Ohio Valleys, which could tend toward upscale
   growth toward linear/bowing segments.  While some risk for a couple
   of tornadoes may evolve -- particularly near remnant boundaries,
   damaging winds along with some hail can be expected.  Threat may
   continue through much of the evening, spreading eastward across the
   Ohio and Tennessee Valleys.

   Meanwhile, a broader zone of lesser risk appears to extend eastward
   to the Appalachians region, where ample afternoon CAPE but weaker
   flow aloft suggests more disorganized convection.  A risk for
   damaging winds locally, along with some hail, can be expected with
   stronger cells from afternoon through early evening. 

[jaxjagman]

5 hours ago, nrgjeff said:

Monday I busted in South Georgia. Tuesday the best storm came right over my house by about 02Z Wed. We had nice lightning and thunder with torrential rain. Too bad no hail in tropical precip.

Thursday nice mid-level winds and short-wave are forecast. Regrettably 850/925 mb is terribly veered. I know Dixie can give a little compared to the Plains, but this is a deal killer. 2018, sigh. Actually Kentucky should get severe, but probably wind/hail.

Was watching the radar and it looked like a band trained around the Chatty area for a couple hours around the time you are talking about.We got one good band with no thunder

[nrgjeff]

Yes that was the band of CHA precip. I saw the BNA metro got nice bands too. 

17 hours ago, jaxjagman said:

Was watching the radar and it looked like a band trained around the Chatty area for a couple hours around the time you are talking about.We got one good band with no thunder

Today/Thursday might feature some hailers in Kentucky. Just enough wind fields justify 2% TOR and maybe just maybe a small 5% West Kentucky. 

Friday the Marginal could turn to Slight if we can get a little better wind fields over the Tennessee Valley.

Saturday has more questions than answers. Looks like a roaring MCS will slice through Missouri. Warm front should be in Illinois. The IL WF will be what's left of their CF Friday. I love retreating boundaries (that never scoured out dews south of them). Saturday problems include jungle terrain and possible huge MCC/bow. If evidence increases for discrete Saturday, I might have to chase.. I mean visit my buddy in Memphis. Worst case bust scenario: Beale St. Not bad for 2018, lol!