Easter Weekend Severe Thread

[janetjanet998]

Perhaps this could be the main thread for the entire event? even though it could include multiple sub forums .   The SE forum has a thread going but their threads tend to be more in my back yard type stuff ( which is fine) and not general severe weather super thread tracking

for starters

 

 

DAY 3 CONVECTIVE OUTLOOK    
NWS STORM PREDICTION CENTER NORMAN OK  
0227 AM CDT THU APR 09 2020  
  
VALID 111200Z - 121200Z  
  
...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS FOR MUCH OF TX  
INTO THE LA GULF COAST...  
   
..SUMMARY  
  
SEVERE THUNDERSTORMS WILL BE POSSIBLE ACROSS MUCH OF TEXAS INTO  
PORTIONS OF THE LOWER MISSISSIPPI VALLEY, WITH THE GREATEST THREAT  
LIKELY SATURDAY NIGHT INTO EARLY SUNDAY MORNING. LARGE HAIL,  
DAMAGING WIND, AND PERHAPS A COUPLE OF TORNADOES WILL BE THE PRIMARY  
THREATS.  
   
..SYNOPSIS  
  
THE PERSISTENT UPPER LOW OVER THE SOUTHWEST IS FORECAST TO EJECT  
EASTWARD ON SATURDAY, AS A NORTHERN STREAM MID/UPPER-LEVEL TROUGH  
MOVES SOUTHEASTWARD INTO THE NORTHWEST AND NORTHERN ROCKIES.  
DOWNSTREAM, AN UPPER RIDGE WILL DEVELOP OVER PORTIONS OF THE EASTERN  
CONUS BY SUNDAY MORNING IN THE WAKE OF AN UPPER TROUGH MOVING OVER  
THE WESTERN ATLANTIC, WHICH WILL ALLOW THE EJECTING TROUGH TO TAKE  
ON A MORE NEUTRAL TILT BY THE END OF THE PERIOD. AT THE SURFACE, LOW  
PRESSURE IS FORECAST TO DEEPEN OVER THE CENTRAL HIGH PLAINS, TO THE  
SOUTH OF A COLD FRONT THAT WILL SWEEP ACROSS THE NORTHERN HIGH  
PLAINS BY SATURDAY EVENING.   
   
..MUCH OF TX INTO THE LOWER MS VALLEY  
  
RICH LOW-LEVEL MOISTURE OVER THE WESTERN GULF OF MEXICO IS FORECAST  
TO BEGIN SPREADING INTO PORTIONS OF SOUTH INTO CENTRAL TX AT SOME  
POINT SATURDAY/SATURDAY NIGHT, THOUGH THIS PROCESS COULD BE DELAYED  
SOMEWHAT DEPENDING ON THE INFLUENCE OF A LINGERING SURFACE RIDGE  
THAT WILL INITIALLY BE IN PLACE ALONG THE GULF COAST. WHILE  
SURFACE-BASED DESTABILIZATION MAY BE LIMITED DURING THE DAY,  
BUOYANCY IS FORECAST TO SUBSTANTIALLY INCREASE SATURDAY NIGHT, AS  
STEEPER MIDLEVEL LAPSE RATES ASSOCIATED WITH THE EJECTING TROUGH  
SPREAD OVER MUCH OF TX AMIDST CONTINUED LOW-LEVEL MOISTENING.   
  
ELEVATED CONVECTION WILL LIKELY ERUPT SATURDAY NIGHT ACROSS SOME  
PORTION OF WEST/CENTRAL TX, WITH AN INITIAL HAIL THREAT. SOME STORMS  
MAY BECOME ROOTED CLOSER TO THE SURFACE AS THEY ENCOUNTER GREATER  
LOW-LEVEL MOISTURE, WITH A CORRESPONDING THREAT OF DAMAGING WIND AND  
PERHAPS A TORNADO OR TWO GIVEN INCREASINGLY FAVORABLE WIND PROFILES.  
THERE WILL ALSO BE SOME POTENTIAL FOR SURFACE-BASED CONVECTION TO  
DEVELOP NEAR THE NORTHWARD-MOVING WARM FRONT ALONG THE UPPER TX/LA  
GULF COAST PRIOR TO 12Z SUNDAY MORNING, WHICH WOULD POSE A  
CONDITIONAL RISK OF ALL SEVERE HAZARDS.   
  
GIVEN THE ANTICIPATED LATE TIMING OF THE HIGHER-END SEVERE  
POTENTIAL, 15% SEVERE PROBABILITIES HAVE BEEN MAINTAINED FOR THIS  
OUTLOOK, BUT THERE IS SOME POTENTIAL FOR HIGHER PROBABILITIES ONCE  
DETAILS REGARDING LOW-LEVEL MOISTURE RETURN AND THE EVOLUTION OF  
LATE-NIGHT CONVECTION COME INTO BETTER FOCUS.    
   
..NORTHWEST TX INTO CENTRAL KS  
  
MODEST LOW-LEVEL MOISTURE THAT IS TRANSPORTED INTO PORTIONS OF WEST  
TX ON FRIDAY WILL ADVECT NORTHWARD INTO A LARGER PORTION OF THE  
SOUTHERN/CENTRAL PLAINS ON SATURDAY. DURING THE AFTERNOON, MODERATE  
INSTABILITY MAY DEVELOP FROM NORTHWEST TX INTO CENTRAL KS, AS  
DEWPOINTS IN THE 50S F ARE ADVECTED NORTHWARD BENEATH STEEP MIDLEVEL  
LAPSE RATES. WIDELY SCATTERED THUNDERSTORM DEVELOPMENT IS POSSIBLE  
ALONG A SURFACE TROUGH/DRYLINE. WHILE MIDLEVEL FLOW IS FORECAST TO  
BE ONLY MODEST AT BEST ACROSS THIS REGION BY LATE AFTERNOON, 25-35  
KT OF EFFECTIVE SHEAR MAY SUPPORT SOME STORM ORGANIZATION WITH A  
CORRESPONDING HAIL RISK.  
  
..DEAN/DIAL.. 04/09/2020  

 

 

DAY 4-8 CONVECTIVE OUTLOOK    
NWS STORM PREDICTION CENTER NORMAN OK  
0354 AM CDT THU APR 09 2020  
  
VALID 121200Z - 171200Z  
   
..SEVERE WEATHER OUTBREAK POSSIBLE ON D4/SUN  
  
   
..DISCUSSION  
  
AN OUTBREAK OF SEVERE THUNDERSTORMS APPEARS POSSIBLE ON SUNDAY  
ACROSS PARTS OF LOUISIANA, MISSISSIPPI, ALABAMA, AND POSSIBLY INTO  
GEORGIA BY SUNDAY NIGHT. TORNADOES (POTENTIALLY STRONG/LONG-TRACKED)  
AND WIDESPREAD DAMAGING WINDS ARE EXPECTED TO BE THE PRIMARY  
HAZARDS.   
  
...D4/SUNDAY: TX GULF COAST EASTWARD THROUGH THE SOUTHEAST INTO THE  
CAROLINAS...  
INGREDIENTS FOR A POTENTIAL SEVERE THUNDERSTORM OUTBREAK APPEAR  
LIKELY TO COME TOGETHER SUNDAY INTO SUNDAY NIGHT. AN EJECTING  
SHORTWAVE TROUGH IS FORECAST TO TAKE ON A NEUTRAL TO SOMEWHAT  
NEGATIVE TILT BY SUNDAY AFTERNOON AS IT MOVES QUICKLY  
EAST-NORTHEASTWARD ACROSS THE SOUTHEAST STATES. RICH LOW-LEVEL  
MOISTURE WILL BE DRAWN INLAND FROM THE GULF OF MEXICO IN ADVANCE OF  
A DEEPENING SURFACE LOW THAT WILL MOVE FROM THE MID-MS VALLEY INTO  
THE OHIO VALLEY BY MONDAY MORNING. MODERATE DESTABILIZATION IN  
CONJUNCTION WITH AN 80-100 KT MIDLEVEL JET AND 50-60 KT LOW-LEVEL  
JET WILL RESULT IN A VERY FAVORABLE ENVIRONMENT FOR ORGANIZED  
CONVECTION, INCLUDING THE POTENTIAL FOR LONG-TRACK SUPERCELLS AND A  
CORRESPONDING STRONG TORNADO RISK. VERY STRONG LOW/MIDLEVEL FLOW  
FIELDS WILL ALSO SUPPORT WIDESPREAD DAMAGING WIND POTENTIAL.   
  
SOME UNCERTAINTY REMAINS REGARDING THE NORTHWARD EXTENT OF THE MOST  
SIGNIFICANT SEVERE POTENTIAL, GIVEN THE PRESENCE OF WIDESPREAD  
CONVECTION IN ADVANCE OF THE EJECTING SHORTWAVE. GUIDANCE ALSO  
CONTINUES TO TREND SLIGHTLY SLOWER, WITH THE GFS STILL A NOTABLY  
FAST OUTLIER. A 30% PROBABILITY CONTOUR HAS BEEN INTRODUCED FROM LA  
INTO CENTRAL/SOUTHERN MS/AL AND SOUTHWEST GA, WHERE CONFIDENCE IS  
HIGHEST IN THE OUTBREAK POTENTIAL AT THIS TIME.  
  
AN ORGANIZED SEVERE THUNDERSTORM THREAT WILL LIKELY CONTINUE INTO  
MONDAY MORNING, WITH THE POTENTIAL FOR DAMAGING WIND AND/OR A FEW  
TORNADOES LIKELY SPREADING INTO PORTIONS OF THE CAROLINAS BY 12Z  
MONDAY.

 

[Tallis Rockwell]

Decent stuff this week.

Waiting for a watch in central Texas

[DanLarsen34]

People in the SE forum have already been highlighting just how significant the threat could be on Sunday.
 

Synoptically obvious outbreak set-up. Low position is about as favorable as you’ll see for a Dixie outbreak. Models converging on higher-end solutions right now. Speed and directional shear are very high-end. CAPE is still in the moderate range (1,000-2,000 j/kg) on models, but that may not be a significant mitigator. It’s more than sufficient for an outbreak. 
 

We could be dealing with a major tornado outbreak across LA, MS, and AL on Sunday.

[jojo762]

Saturday does not look too bad across KS/OK (especially near the triple-point in Kansas)... Could be one of those sneaky days where nothing particularly stands out about the environment, but lapse rates are steep enough, and hodographs have a beautiful sickle shape, so a supercell or two might be able to go off for an hour or two.

[brianc33710]

ABC 33/40 Meteorologist James Spann shared soundings for Tuscaloosa, AL Sunday afternoon. He says that the forecast show a PDS situation and that the trends aren't looking good for the SE.  Spann shows the soundings between 3:35 & 3:50 on this afternoon's Xtream Weather video. 

[brianc33710]

Fred Gossage, also a Birmingham, AL meteorologist (and he was once active on here), posted about the potential danger from Sunday's event on his personal FB page. I am not a friend of his, but you can see what he has written on his personal Facebook page.

[janetjanet998]

it will all of course depend on the warm front position but NAM wants TN to get some of the action too

"SPC day" storm report map 12z SUN to 12z Monday  will be interesting from east Texas to NC

 

[brianc33710]

41 minutes ago, janetjanet998 said:

it will all of course depend on the warm front position but NAM wants TN to get some of the action too

"SPC day" storm report map 12z SUN to 12z Monday  will be interesting from east Texas to NC

 

We will know more tomorrow morning. Unlike during hurricane season, I don't plan to stay up on edge for every model update.

[Tallis Rockwell]

18z NAM is showing a more some good helicity over East TX.

 

[cheese007]

Big D3 mod with 45% hatched area. Haven't seen that in a hot minute

[janetjanet998]

DAY 3 CONVECTIVE OUTLOOK    
NWS STORM PREDICTION CENTER NORMAN OK  
0244 AM CDT FRI APR 10 2020  
  
VALID 121200Z - 131200Z  
  
...THERE IS A MODERATE RISK OF SEVERE THUNDERSTORMS FOR  
CENTRAL/NORTHERN LOUISIANA...SOUTHEAST  
ARKANSAS...MISSISSIPPI...WESTERN/CENTRAL ALABAMA...  
   
..SUMMARY  
  
AN OUTBREAK OF SEVERE THUNDERSTORMS APPEARS LIKELY SUNDAY INTO  
SUNDAY NIGHT, WITH THE GREATEST THREAT EXPECTED FROM LOUISIANA  
EAST-NORTHEASTWARD THROUGH MUCH OF THE SOUTHEAST AND TENNESSEE  
VALLEY. STRONG, LONG-TRACKED TORNADOES AND POTENTIALLY WIDESPREAD  
DAMAGING WIND ARE POSSIBLE.  
   
..SYNOPSIS  
  
THE EJECTING SHORTWAVE TROUGH INITIALLY OVER THE SOUTHERN HIGH  
PLAINS SUNDAY MORNING IS FORECAST TO MOVE QUICKLY EASTWARD AND THEN  
NORTHEASTWARD THROUGH THE PERIOD, AS IT MOVES AROUND THE PERIPHERY  
OF A DEEPENING LONGWAVE TROUGH OVER THE CENTRAL CONUS. AS THIS  
OCCURS, A SURFACE LOW WILL MOVE EASTWARD TO THE MISSISSIPPI VALLEY  
BY SUNDAY AFTERNOON, AND THEN RAPIDLY DEEPEN AND MOVE NORTHEASTWARD  
INTO THE LOWER GREAT LAKES BY MONDAY MORNING. VERY STRONG MASS  
RESPONSE WILL DRAW RICH LOW-LEVEL MOISTURE NORTHWARD INTO PORTIONS  
OF THE SOUTHEAST.   
   
..EAST TEXAS INTO THE SOUTHEAST  
  
INGREDIENTS FOR A POTENTIAL SEVERE THUNDERSTORM OUTBREAK STILL  
APPEAR LIKELY TO COME TOGETHER SUNDAY. MODERATE TO LOCALLY STRONG  
DESTABILIZATION IN CONJUNCTION WITH AN 80-100 KT MIDLEVEL JET AND  
50-60 KT LOW-LEVEL JET WILL RESULT IN A VERY FAVORABLE ENVIRONMENT  
FOR ORGANIZED CONVECTION. ONGOING STORMS ACROSS EAST TX SUNDAY  
MORNING WILL LIKELY SPREAD NORTHEASTWARD WITH TIME AND BECOME  
INCREASINGLY SURFACE BASED AS THEY ENCOUNTER RAPIDLY INCREASING  
LOW-LEVEL MOISTURE, WITH ADDITIONAL DEVELOPMENT POSSIBLE FURTHER  
SOUTH NEAR THE LOWER MS RIVER VALLEY BY LATE MORNING. AS THE  
DOWNSTREAM AIRMASS HEATS AND DESTABILIZES, LONG-TRACK SUPERCELLS MAY  
EVOLVE OUT OF THE MORNING CONVECTION AND TRACK NORTHEASTWARD INTO  
PORTIONS OF MS/AL, WITH A CORRESPONDING RISK OF STRONG TORNADOES,  
LARGE HAIL, AND DAMAGING WIND GUSTS. SOME UPSCALE GROWTH IS POSSIBLE  
WITH TIME, WHICH WOULD RESULT IN A CORRESPONDING WIDESPREAD DAMAGING  
WIND RISK, GIVEN EXTREMELY STRONG WIND FIELDS. SOME THREAT OF  
DAMAGING WIND AND A FEW TORNADOES WILL LIKELY REACH PORTIONS OF THE  
CAROLINAS BY 12Z MONDAY.   
   
..MID MS VALLEY INTO THE OH VALLEY  
  
DESTABILIZATION IN THE VICINITY OF THE PRIMARY SURFACE LOW INTO THE  
MID MS VALLEY/OH VALLEY IS MORE UNCERTAIN, GIVEN THE POTENTIAL FOR  
DISRUPTIVE CONVECTION FURTHER SOUTH. HOWEVER, FAVORABLE WIND  
PROFILES AND CLOSER PROXIMITY TO THE EJECTING SHORTWAVE WILL SUPPORT  
SOME SEVERE THUNDERSTORM THREAT IN THIS REGION AS WELL, WITH A  
CONDITIONAL RISK OF ALL HAZARDS GIVEN SUFFICIENT DESTABILIZATION.  

[DanLarsen34]

That’s the largest day 3 moderate risk I’ve ever seen. 

[brianc33710]

1 hour ago, DanLarsen34 said:

That’s the largest day 3 moderate risk I’ve ever seen. 

Yeah, Birmingham is now in level 4/5. James Spann remarked in this morning's Weather Extreme video that the SPC typically doesn't issue a Moderate Risk for day 3. At least with everyone stuck watching Easter services on TV everyone should be close to, if not at, home when the storms come through.

[janetjanet998]

we could have a 1000 filtered SPC storm report day 12z Sunday to 12z Monday .....I have only seen that a few times, mostly from huge a derecho that starts in the midwest and surges into the southeast with lots of tree damage reports (helped by lots of trees in the SE ,don't have that in KS)

but with convection ongoing over TX at 12z and continuing and more redeveloping ENE all the way to mid NC by 12z Monday it is possible...

 

bonus reports anything that can develop NW of the main action over eastern OK into MO and AR behind the main stuff

 

plus social media and better spotter network will add to any storms reports may then say 10-20 years ago

 

[Tallis Rockwell]

A pretty sound for southeast TX from 12z NAM

[WhiteoutWX]

I think this setup has some potential, but the strong forcing will likely mean a lot of storms. Hodographs are decent in spots but the VBV signature is there in many of them and critical angles are not very ideal. I think you will see a lot of storms struggling to maintain discrete modes. I would bet on a ton of wind and hail reports with mostly weak/brief tornadoes. If we can get some discrete supercells with some deviant easterly motion there could be a strong tornado or two but I am just not seeing large widespread tornado outbreak out of this setup. 

[Chinook]

Before we get to Sunday, the SPC's day-2 outlook has a 30% risk of hail in southern Texas, from the Rio Grande/ Eagle Pass area up to San Antonio vicinity. The outlook for wind is larger, but it's at 15%.

06z Sunday: dew points of 70F will be in the area of San Antonio with over 3000 J/kg of MUCAPE, with a most-unstable level above the surface. Even with the possibility of reduced shear due to elevated inflow, the 500mb winds will be around 65kt to 80kt, and there is turning of wind (SRH) between 1km and 3km. This is a very impressive CAPE for being 1:00AM-- many hours after sunset.

[Quincy]

Fort Stockton supercell special this afternoon, too? Active pattern for sure. 

[janetjanet998]

Day 2....

 

.CENTRAL/SOUTHERN PLAINS SATURDAY MORNING INTO SATURDAY EVENING  
  
POTENTIAL EXISTS FOR SHOWERS AND THUNDERSTORMS TO BE ONGOING IN TWO  
DISTINCT AREAS SATURDAY MORNING. ONE IS WITHIN REMNANT OF THE  
NOCTURNAL LOW-LEVEL JET AND NEAR THE LEADING EDGE OF THE HIGHER  
THETA-E AIR ADVECTING NORTHWARD, ROUGHLY FROM SOUTHWEST TX INTO THE  
SOUTHERN PANHANDLE AND LOW ROLLING PLAINS. THIS CLUSTER IS EXPECTED  
TO MOVE EAST-NORTHEASTWARD THROUGHOUT THE DAY, JUST AHEAD OF A  
DRYLINE. AS IT DOES, THERMODYNAMIC PROFILES WILL BECOME INCREASINGLY  
FAVORABLE FOR SEVERE HAIL.   
  
A SECOND CLUSTER MAY BE ONGOING AT THE BEGINNING OF THE PERIOD NORTH  
OF THE WARM FRONT IN SOUTHEAST TX. HAIL WILL ALSO BE POSSIBLE WITHIN  
THESE STORMS FOR A FEW HOURS IN THE MORNING BEFORE THE STORMS BECOME  
DISPLACED EAST OF THE BETTER WARM-AIR ADVECTION, WHICH WILL BE  
RESTRENGTHENING BACK WEST ACROSS CENTRAL TX. CONDITIONAL THREAT FOR  
A TORNADO EXISTS WITH ANY SURFACE-BASED STORMS, BUT THE CURRENT  
EXPECTATION IS FOR THE STORMS TO STAY NORTH OF THE WARM FRONT.   
  
ONE ADDITIONAL AREA OF AFTERNOON/EVENING DEVELOPMENT IS ALONG THE  
DRYLINE ACROSS THE TX PANHANDLE AND INTO CENTRAL KS. GUIDANCE VARIES  
ON THE OVERALL CONVECTIVE COVERAGE, ESPECIALLY WITH NORTHERN EXTENT  
IN TO KS, BUT ISOLATED HAIL AND/OR DAMAGING DOWNBURSTS ARE POSSIBLE  
IF STORMS MATERIALIZE.   
   
..TX SATURDAY EVENING THROUGH SUNDAY MORNING  
  
AS THE SHORTWAVE TROUGH APPROACHES, LARGE-SCALE FORCING FOR ASCENT  
WILL BEGIN TO INTERACT WITH THE WARM, MOIST, AND BUOYANT AIR MASS  
ACROSS TX. AS IT DOES, RE-DEVELOPMENT IS ANTICIPATED ALONG THE  
SOUTHERN END OF THE DRYLINE FROM SOUTHWEST TX INTO THE BIG  
BEND/EDWARDS PLATEAU. INITIAL DEVELOPMENT WILL HAVE A THREAT FOR ALL  
SEVERE HAZARDS, WITH THE GREATEST SEVERE POTENTIAL COMING FROM LARGE  
TO VERY-LARGE HAIL. QUICK UPSCALE GROWTH SEEMS PROBABLE, WITH THE  
RESULTING CONVECTIVE LINE MOVING EASTWARD ACROSS CENTRAL TX AND INTO  
EAST TX BY EARLY SUNDAY MORNING. GIVEN THE STRENGTHENING LOW TO  
MID-LEVEL FLOW, POTENTIAL FOR TORNADOES WILL EXIST WITHIN THE LINE  
(ESPECIALLY ALONG THE SOUTHERN FLANK), AS WELL AS WITH ANY  
DEVELOPMENT OUT AHEAD OF THE MAIN CONVECTIVE LINE IN THE WARM  
SECTOR.  
  
..MOSIER.. 04/10/2020  

[JasonOH]

A great thread by a friend of mine talking about the OK portion of the severe threat tomorrow.

 

[andyhb]

6 hours ago, WhiteoutWX said:

I think this setup has some potential, but the strong forcing will likely mean a lot of storms. Hodographs are decent in spots but the VBV signature is there in many of them and critical angles are not very ideal. I think you will see a lot of storms struggling to maintain discrete modes. I would bet on a ton of wind and hail reports with mostly weak/brief tornadoes. If we can get some discrete supercells with some deviant easterly motion there could be a strong tornado or two but I am just not seeing large widespread tornado outbreak out of this setup. 

I'll tell right now that with those shear profiles, VBV isn't going to make a large difference. Also the critical angles are between 45 and 65˚ in most soundings I've pulled, which is well within the typical range seen in Dixie. That's not even accounting for the fact that mesoscale factors can alter critical angles significantly.

On top of that, even with mixed mode here, any embedded spin ups will be producing tornadoes and potentially strong ones with such high 0-1 km SRH (and this continues all the way to the Eastern Seaboard). To assume a mixed mode or even a QLCS here means "brief/weak tornadoes" would be a mistake.

[Sydney Claridge]

1 hour ago, JasonOH said:

A great thread by a friend of mine talking about the OK portion of the severe threat tomorrow.

 

Long story short, just to rehash that discussion, it basically says that we need to watch the evolution of that storm activity currently out by Midland and Lubbock.  If said activity evolves into an MCS and persists as it moves eastwards into north-central Texas and Oklahoma (which seems to be the most likely scenario), then that convective activity will leave behind a cold pool, cutting off severe weather potential and N TX and OK.  That HRRR run has the Midland/Lubbock activity fall apart and fail to grow upscale into an MCS.

[brianc33710]

1 hour ago, andyhb said:

I'll tell right now that with those shear profiles, VBV isn't going to make a large difference. Also the critical angles are between 45 and 65˚ in most soundings I've pulled, which is well within the typical range seen in Dixie. That's not even accounting for the fact that mesoscale factors can alter critical angles significantly.

On top of that, even with mixed mode here, any embedded spin ups will be producing tornadoes and potentially strong ones with such high 0-1 km SRH (and this continues all the way to the Eastern Seaboard). To assume a mixed mode or even a QLCS here means "brief/weak tornadoes" would be a mistake.

Okay, I will share what I wrote on another weather talk site since it applies here two ways, so this isn't plagiarism:

I think maybe this event would resemble a 15 April 2011 with an EF-4 or 5 added in to the event, MAYBE 2 4/5s at most. I guess the # of tornadoes in 2011 + the violent tornado from 08 April 1998. This would resemble a once-a-decade type of event but short of a superoutbreak.

I guess one other thing I'm trying to say, beyond the fact that I think 27 April 2011 is a generational/meteorology career type of even, is those less informed weather geeks (no shade, see below) who get high on the hype leading up to that event. Looking back thru these weather threads from 9 yrs ago, some of the bloggers & members kept hoping that the event WOULD live up to its potential, and went into overdrive once the storms began to fire.

Of course, that event did live up to 90-95% of its potential, so these overeager members did indeed get what they "wanted." However they had failed to anticipate the hundreds of deaths, the thousands of injuries, and the billions of dollars that would result from that superoutbreak. So, from a fellow weather geek (but more informed) like myself, PLEASE be careful for what you wish for. Once you get it, the guilt and sadness could last you a lifetime.

 

[Sydney Claridge]

40 minutes ago, brianc33710 said:

Okay, I will share what I wrote on another weather talk site since it applies here two ways, so this isn't plagiarism:

I think maybe this event would resemble a 15 April 2011 with an EF-4 or 5 added in to the event, MAYBE 2 4/5s at most. I guess the # of tornadoes in 2011 + the violent tornado from 08 April 1998. This would resemble a once-a-decade type of event but short of a superoutbreak.

I guess one other thing I'm trying to say, beyond the fact that I think 27 April 2011 is a generational/meteorology career type of even, is those less informed weather geeks (no shade, see below) who get high on the hype leading up to that event. Looking back thru these weather threads from 9 yrs ago, some of the bloggers & members kept hoping that the event WOULD live up to its potential, and went into overdrive once the storms began to fire.

Of course, that event did live up to 90-95% of its potential, so these overeager members did indeed get what they "wanted." However they had failed to anticipate the hundreds of deaths, the thousands of injuries, and the billions of dollars that would result from that superoutbreak. So, from a fellow weather geek (but more informed) like myself, PLEASE be careful for what you wish for. Once you get it, the guilt and sadness could last you a lifetime.

 

All I can say is that with the ongoing COVID-19 pandemic, emergency managers, hospitals, and public health authorities need to have a plan for how they are going to deal with the displaced and injured, especially should a strong-to-violent tornado strike a well-populated area in the coming days.  That grim outcome is definitely a possibility, though not a certainty by any means.  Keep in mind that anyone who is displaced or injured would be at a greater risk for catching (or spreading) COVID-19.  I have not heard too much about overburdened hospitals in the South outside of New Orleans (and even they are in the risk area here, though the most severe activity should be to the north of them), but this potential tornado outbreak could not be coming at a worse time.

While tracking storms can be exciting, the death, displacement, and destruction they cause are anything but exciting.  Honestly I hope this busts completely, but the signals are there for a potential tornado outbreak.

[Indystorm]

Well, mother nature is amoral....brute force is brute force.  It's not out to get us.  It follows laws of physics and thermodynamics.  But your concern with something of this magnitude happening with Covid-19 impacting us is certainly warranted.

[Indystorm]

And in some action for Good Friday night....

  
BULLETIN - EAS ACTIVATION REQUESTED  
SEVERE THUNDERSTORM WARNING  
NATIONAL WEATHER SERVICE SAN ANGELO TX  
855 PM CDT FRI APR 10 2020  
  
THE NATIONAL WEATHER SERVICE IN SAN ANGELO HAS ISSUED A  
  
* SEVERE THUNDERSTORM WARNING FOR...  
  NORTH CENTRAL AND NORTHEASTERN CROCKETT COUNTY IN WEST CENTRAL   
  TEXAS...  
  
* UNTIL 1000 PM CDT.  
  
* AT 854 PM CDT, A SEVERE THUNDERSTORM WAS LOCATED 11 MILES SOUTH OF  
  REAGAN COUNTY AIRPORT, OR 11 MILES SOUTHWEST OF BIG LAKE, MOVING  
  EAST AT 25 MPH.  
  
  THIS IS A VERY DANGEROUS STORM.  
  
  HAZARD...BASEBALL SIZE HAIL AND 60 MPH WIND GUSTS.  
  
  SOURCE...RADAR INDICATED.  
  
  IMPACT...PEOPLE AND ANIMALS OUTDOORS WILL BE SEVERELY INJURED.   
           EXPECT SHATTERED WINDOWS, EXTENSIVE DAMAGE TO ROOFS,   
           SIDING, AND VEHICLES.  
  
* THIS SEVERE THUNDERSTORM WILL REMAIN OVER MAINLY RURAL AREAS OF  
  NORTHEASTERN CROCKETT COUNTY, INCLUDING THE FOLLOWING LOCATIONS...  
  THE INTERSECTION OF US 190 AND HIGHWAY 163.  

[WhiteoutWX]

2 hours ago, andyhb said:

I'll tell right now that with those shear profiles, VBV isn't going to make a large difference. Also the critical angles are between 45 and 65˚ in most soundings I've pulled, which is well within the typical range seen in Dixie. That's not even accounting for the fact that mesoscale factors can alter critical angles significantly.

On top of that, even with mixed mode here, any embedded spin ups will be producing tornadoes and potentially strong ones with such high 0-1 km SRH (and this continues all the way to the Eastern Seaboard). To assume a mixed mode or even a QLCS here means "brief/weak tornadoes" would be a mistake.

Im not assuming anything just my interpretation of the data I’m seeing and my own personal forecast. We’ve seen events with much better parameters produce much less than what you are describing. Plenty of events that are hyped days out end up being messy and lacking many strong tornadoes. I could be wrong that’s just my interpretation though. 

[andyhb]

1 minute ago, WhiteoutWX said:

Im not assuming anything just my interpretation of the data I’m seeing and my own personal forecast. We’ve seen events with much better parameters produce much less than what you are describing. Plenty of events that are hyped days out end up being messy and lacking many strong tornadoes. I could be wrong that’s just my interpretation though. 

The event in January comes to mind. That QLCS was very prolific, produced several long-tracked tornadoes (and several EF2s), and led to several deaths despite instability quite a bit lower than this. There is also a substantial after dark component to this, which extends to the East Coast.

I don't really know what you mean by "what I'm describing". If you're implying I'm saying the doom of the SE is coming on Sunday, that's definitely not it. A high end outbreak is not locked in, but saying brief, weak tornadoes are mostly going to happen with this level of shear and low level moisture regardless of storm mode is also a bit on the extreme side.

[WhiteoutWX]

18 minutes ago, andyhb said:

The event in January comes to mind. That QLCS was very prolific, produced several long-tracked tornadoes (and several EF2s), and led to several deaths despite instability quite a bit lower than this. There is also a substantial after dark component to this, which extends to the East Coast.

I don't really know what you mean by "what I'm describing". If you're implying I'm saying the doom of the SE is coming on Sunday, that's definitely not it. A high end outbreak is not locked in, but saying brief, weak tornadoes are mostly going to happen with this level of shear and low level moisture regardless of storm mode is also a bit on the extreme side.

I was just trying to point out some potential fail modes that I hadn’t seen mentioned and giving my opinion on what might play out. May 20 of last year was higher end on both shear and instability and barely any strong tornadoes occurred. I’m not saying a high end event is impossible here, just that there are definitely factors in play that could derail the event. I don’t pretend to know all the answers though. No one does.
 

[brianc33710]

Two things for discussion:

James Spann actually thinks that the SPC will go with the High Risk next update, which seems a little too soon. But he has 40 + years of experience so I will defer to him.

Also, is the Nashville, TN EF-4 the only violent tornado so far in 2020? I know that they also had an EF-3, but their NWS office did find some EF-4 damage.