2018 severe wx/chase season discussion

I don't think it necessarily means much on the big scale, but I drove across the panhandles yesterday and even before the fires, the ground and vegetation were very dry and frail looking. The amount of land that burned yesterday alone was impressive, but then again, I've only frequented the southern Plains since 2014, so I can't speak to how previous droughts and/or fire seasons looked. The setup for fire ignition and spread was quite near historic, so that didn't help matters. In a more mesoscale sense, it's entirely possible that moisture return/quality may be at least slightly augmented by the drought, if it does not improve. On a lighter note, the large scale pattern does support at least some uptick in precipitation opportunities for portions of the southern High Plains and vicinity.

Anyway, I'm not overly excited about the coming weeks. There is some sign of a more zonal pattern with shortwave troughs crossing the U.S. next week and into the final week of April. I've said it before and climo suggests an uptick in this sort of activity in late April, even in otherwise "quiet" tornado seasons.

I'm not so sure what May will have to offer. The CFS has been consistently AOB average in terms of severe potential through the end of April and I don't take the model very seriously beyond week 2, as one would probably have better verification with climatology. With that said, the latest Euro weeklies showed a dreaded western ridge/eastern trough setup developing in early May. The brighter side is that as we get deeper into the season, it becomes easier for adequate moisture with northward extent, so setups that may have proved marginal/insufficient in March/early April will fare better in May.

My take on the next 2-3 weeks: Increased severe activity, as one would expect, but no signs of any major systems and/or extended periods of AOA severe activity.
 
I don't think it necessarily means much on the big scale, but I drove across the panhandles yesterday and even before the fires, the ground and vegetation were very dry and frail looking. The amount of land that burned yesterday alone was impressive, but then again, I've only frequented the southern Plains since 2014, so I can't speak to how previous droughts and/or fire seasons looked. The setup for fire ignition and spread was quite near historic, so that didn't help matters. In a more mesoscale sense, it's entirely possible that moisture return/quality may be at least slightly augmented by the drought, if it does not improve. On a lighter note, the large scale pattern does support at least some uptick in precipitation opportunities for portions of the southern High Plains and vicinity.

Anyway, I'm not overly excited about the coming weeks. There is some sign of a more zonal pattern with shortwave troughs crossing the U.S. next week and into the final week of April. I've said it before and climo suggests an uptick in this sort of activity in late April, even in otherwise "quiet" tornado seasons.

I'm not so sure what May will have to offer. The CFS has been consistently AOB average in terms of severe potential through the end of April and I don't take the model very seriously beyond week 2, as one would probably have better verification with climatology. With that said, the latest Euro weeklies showed a dreaded western ridge/eastern trough setup developing in early May. The brighter side is that as we get deeper into the season, it becomes easier for adequate moisture with northward extent, so setups that may have proved marginal/insufficient in March/early April will fare better in May.

My take on the next 2-3 weeks: Increased severe activity, as one would expect, but no signs of any major systems and/or extended periods of AOA severe activity.

I noticed this as well, and made note of it as it appeared on most of my more heavily weighted analogs (see post on last page). Starting to see it towards the tail end of the latest ECMWF EPS as well. Again, analogs are just one part of the picture and there is a lot more to the overall hemispheric pattern progression. But it's interesting to see this kind of idea start to show up at least in some fashion on modeling.

maynope.png
 
I noticed this as well, and made note of it as it appeared on most of my more heavily weighted analogs (see post on last page). Starting to see it towards the tail end of the latest ECMWF EPS as well. Again, analogs are just one part of the picture and there is a lot more to the overall hemispheric pattern progression. But it's interesting to see this kind of idea start to show up at least in some fashion on modeling.

I'm probably going to end up cancelling my planned chase trip if that ends up being the overall pattern. What a disaster.
 
I'm probably going to end up cancelling my planned chase trip if that ends up being the overall pattern. What a disaster.

I'd wait it out a bit because there are plenty of hemispheric/pattern drivers that are still at play...but early signals aren't exactly what we want to see for May overall. I tend to think, still, that there's potential on the back half of the month. What days are you chasing?
 
I'd wait it out a bit because there are plenty of hemispheric/pattern drivers that are still at play...but early signals aren't exactly what we want to see for May overall. I tend to think, still, that there's potential on the back half of the month. What days are you chasing?

Late May won't be an option for me this year due to graduation and other priorities. Second or third week of May is my window.
 
Hi everyone, I've been a member here for quite some time and chasing even longer...first time to join in on the conversation. By the way, I really appreciate all of the great comments and advice found on this forum. A lot of quality info!

Our chase trip is planned for mid May into early June (pretty usual for us). I can see the late March/early April pattern returning during that time. There have been numerous legit setups that produced nothing or next to nothing.....during May into June I'm betting they give us some pretty good setups with the dryline, cold air still trying to come south and the Gulf of Mexico opening up wide for action.
 
It's pretty remarkable. We get a shortwave crossing over from the Four Corners region, but it's going to be too far south (is this really mid/late April?) for any appreciable severe in the Plains. Thursday is an odd day that could feature some marginally severe activity in the southern Rockies, but moisture return looks meager, even for the higher terrain. Friday is probably going to be wasted too, although it's possible that the southwestern Texas vicinity (or maybe even southeastern New Mexico, if trends continue) gets something, but that keeps trending farther west and narrower with any favorable moisture plume.

Beyond that, the unseasonably far south shortwave makes its way to the Gulf Coast and again, some spotty severe may be possible, but we may escape the first four weeks of April without any higher-end events. The recent Dixie outbreak was noteworthy and probably saves this April from being one of the quietest on record.

In the longer range, there could be some potential around the last weekend of April, but even that time-frame looks like it could be another atmospheric failure. Many GFS/EC ensemble members show some sort of cutoff low getting stuck over the West Coast and either failing to eject or appreciably dampening before reaching the Rockies.

One can be slightly optimistic about early May, but take it for what it's worth, but the Euro Weeklies plunge us into a dreaded western ridge/eastern trough setup for roughly the second to third week of May range.

Either way, it looks increasingly possible that we may manage to go through late April and early May with uncharacteristically low tornado counts, which given the season thus far, would put us very near the bottom of the barrel when it comes to chasing seasons up through that point. Even in the worst chase years, usually there's at least something notable in late April (if not the Plains, then Dixie/Ohio Valley), but it would not surprise me if this year manages to evade that as well. I haven't had a bonafide chase yet this April (two fire days that had some excitement, but just didn't feel very rewarding) and if it wasn't for the Alabama hail/tornado event, I'd probably be pounding my head against the wall at this point. (Figuratively, I'm already doing that)

On the bright side, I'm sure some chasers don't mind saving money and time for later in the season. As bad as the next 3-5 weeks could be, it's almost a given that something "good" will happen between late May and mid-June. Then again, who knows...

P.S. The CFS for the next two weeks (which is the only range I put much stock into it) is probably the quietest I can ever recall it looking for the time period. All blue in the chiclets until May 4th...
 
It's pretty remarkable. We get a shortwave crossing over from the Four Corners region, but it's going to be too far south (is this really mid/late April?) for any appreciable severe in the Plains. Thursday is an odd day that could feature some marginally severe activity in the southern Rockies, but moisture return looks meager, even for the higher terrain. Friday is probably going to be wasted too, although it's possible that the southwestern Texas vicinity (or maybe even southeastern New Mexico, if trends continue) gets something, but that keeps trending farther west and narrower with any favorable moisture plume.

Beyond that, the unseasonably far south shortwave makes its way to the Gulf Coast and again, some spotty severe may be possible, but we may escape the first four weeks of April without any higher-end events. The recent Dixie outbreak was noteworthy and probably saves this April from being one of the quietest on record.

In the longer range, there could be some potential around the last weekend of April, but even that time-frame looks like it could be another atmospheric failure. Many GFS/EC ensemble members show some sort of cutoff low getting stuck over the West Coast and either failing to eject or appreciably dampening before reaching the Rockies.

One can be slightly optimistic about early May, but take it for what it's worth, but the Euro Weeklies plunge us into a dreaded western ridge/eastern trough setup for roughly the second to third week of May range.

Either way, it looks increasingly possible that we may manage to go through late April and early May with uncharacteristically low tornado counts, which given the season thus far, would put us very near the bottom of the barrel when it comes to chasing seasons up through that point. Even in the worst chase years, usually there's at least something notable in late April (if not the Plains, then Dixie/Ohio Valley), but it would not surprise me if this year manages to evade that as well. I haven't had a bonafide chase yet this April (two fire days that had some excitement, but just didn't feel very rewarding) and if it wasn't for the Alabama hail/tornado event, I'd probably be pounding my head against the wall at this point. (Figuratively, I'm already doing that)

On the bright side, I'm sure some chasers don't mind saving money and time for later in the season. As bad as the next 3-5 weeks could be, it's almost a given that something "good" will happen between late May and mid-June. Then again, who knows...

P.S. The CFS for the next two weeks (which is the only range I put much stock into it) is probably the quietest I can ever recall it looking for the time period. All blue in the chiclets until May 4th...

.........it's the CFS.

My thoughts:
CFS.png

I agree that there's some potential for some CAPE-driven threats in the extended range. I'd like to know how euro weeklies compare to climo. My guess is.. we won't know much about May for another 2 weeks or so. Hard to get excited at this point but hard for me to buy the doomsday forecasts coming from all over. Get back to me in May.
 
.........it's the CFS.

My thoughts:
View attachment 16757

I agree that there's some potential for some CAPE-driven threats in the extended range. I'd like to know how euro weeklies compare to climo. My guess is.. we won't know much about May for another 2 weeks or so. Hard to get excited at this point but hard for me to buy the doomsday forecasts coming from all over. Get back to me in May.
The only two days with notable tornado activity in the April 1-7 period were the 3rd and 6th and both had 4-5+ days lead-time with the CFS. What isn't mentioned is that the next day (3/26) is when the CFS started locking in on those active days in early April (the signals were there at least a week in advance).

More often than not, the CFS has shown skill in picking out bigger events 1-2 weeks in advance, given that sometimes there's a 1-2 +/- shift in the dates and geographic placement adjusts. Beyond 14 days, I don't put much stock into the CFS at all. The Euro weeklies on the other hand have shown decent verification even into week 3, but beyond that is when I don't take anything too seriously. There's also the caveat that one single event can skew an entire week (or even month in some cases), so it's not impossible that a bigger event does manage to take place in the coming weeks, but the overall signal is not favorable. I think in terms of chasing, chasers want to know if extended periods look active, as opposed to one day. Many chasers can't/won't make a long trip for a one-off event early in the season, but if a week looks active, they're more likely to pull the trigger.

Victor and team's ERTAF is going with below average activity for their week 2 (4/22-28) forecast and despite officially going with average for week 3 (4/29-5/5), their text discussion argues that many of the signals point toward below average.

For the weeklies, were you asking about verification, or how the model looks compared to climo? For climo, from 4/26 to 5/31 (end of the run) it shows at or above average 500mb heights across the southern/central Plains for 35 out of the 36 days. There is only one brief blip where a trough skirts the area. Death ridge? Not quite, but far from ideal for severe weather.
 
Victor verifies his ERTAF forecasts using preliminary LSRs from SPC...which are notorious for overcounting events. So I wouldn't put much stock into his real-time verification of his forecasts.

Don't expect much in the way of heavy severe activity as long as cold fronts continue to sweep out most of the GoM and the southwest US/northwest Mexico continues to bake. It's great to see troughs, but the troughs are picking up major EMLs and we're just not getting enough low level moisture. Eventually the moisture return will improve, but if the drought situation in the southwest doesn't improve, expect a lot of capped events later this year.

Last April was pretty much a total dud, too, save for the Dimmit and Canton days (both of which in TX and the latter being outside of the traditional April "alley"), so I can't say I'd be too disappointed if April 2018 was another dead month.

With any luck, maybe the late-season will be better in the Midwest and northern Plains. They're getting plenty of moisture up there, but EMLs still get that far north and east, so we will have to wait and see.
 
Speaking of the chiclet chart, yeah I would advise us all not to look at the most recent run of that for the collective sanity of this board alone.

I already had the displeasure of viewing it.
 
Does anyone know if the chiclet charts are archived anywhere? All I see on the CFS dashboard site is the current version. Would be interesting to see how it has performed in the past.
Here are a few takeaways from a subjective analysis that I did of the CFS dashboard:

  • The CFS has virtually no skill beyond week 3 or 21+ days out
  • The CFS skill from weeks 2-3 (14-21 days out) is variable, noting that climatology skews toward increased severe activity in mid to late spring, which questions the validity or importance of CFS "verification" this far out.
  • While the CFS may occasionally zero in on events that are as far as ~3 weeks out, it is not uncommon for the model to flip flop back a few times before getting fully locked in.
  • The CFS is generally very good a week (7 days out) and has shown some skill 1-2 weeks (7-14 days) out, especially early in the season.
I didn't want to go off on too much of a tangent here, so for a more detailed discussion of past CFS verification, feel free to contribute to this thread:
https://stormtrack.org/community/threads/discussing-cfs-dashboard-verification-usefulness.30119/
 
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*Sigh.* Already steeling myself for another wasted spring. What does it take to get an active severe pattern this decade (after the extremes of April 2011, of course)? La Nina, El Nino, anomalous warmth, anomalous cold, nothing works. Need to see a year where events like June 16th-18th, 2014, April 9th, 2015 and May 24th-25th, 2016 are part of a sustained pattern and not just diamonds in the rough...and this isn't going to be it.
 
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