State of the Chase Season 2024

[Warren Faidley]

Looking like some type of severe weather event will take place early next week (2/27 - 2/28) from areas of eastern OK, northwestward into IL. Not going to re-post SPC graphics, but something watch. ATM, models hint of very fast moving HP cells. I'm sure the usual social media suspects will be posting "outbeak" alerts soon.

 

[JA Bruner]

I'm expecting this year to get going fast. I'm also expecting major tornado activity in Dixie Alley.

 

[adlyons]

Looking like some type of severe weather event will take place early next week (2/27 - 2/28) from areas of eastern OK, northwestward into IL. Not going to re-post SPC graphics, but something watch. ATM, models hint of very fast moving HP cells. I'm sure the usual social media suspects will be posting "outbeak" alerts soon.

Been following this as well as I go onto night shifts. Still looks like some typical early-season issues with moisture and diurnal phasing. However, Ensemble support is there for a large trough or series of troughs to potentially support some early season chasing in the next 1-2 weeks.

 

[James Wilson]

I wonder what impact the widespread fires in Texas will have on moisture content now.

 

[Jeff Duda]

I wonder what impact the widespread fires in Texas will have on moisture content now.

My guess would be not much, despite the impressive size of the burned area. There's already not a ton of surface vegetation there, and since it's February and little, if any, of that vegetation has started to green up, the lost potential evaporation is probably low. Also, since it's just Feb, there is a decent chance that by May or so, a lot of vegetation will have already started to grow back (provided it isn't dry as a bone there for weeks after this), which will restore some of that lost potential evaporation.

Finally, most of the moisture in that area advects in from other areas, so it may barely even be noticeable until we get into the greenest part of the year (and assuming the dryline doesn't find residence east of the area).

 

[Jamie H]

It would possibly be more of an issue if the fires were in NM and effecting the EML right?

 

[Jeff Duda]

It would possibly be more of an issue if the fires were in NM and effecting the EML right?

I doubt it. The area burned doesn't correspond to the area with active flame. Unless you're talking about a firestorm in a large forested area with big trees, a wildfire isn't going to raise the PBL mean temperature noticeably, and will only raise the 2-m temperature in areas immediately downwind of burning areas (and probably only within a few hundred meters of the source).

It's just not enough energy input to impact a mesoscale area.

 

[Warren Faidley]

Strange but true, the blackened particles will cause tornadic circulations to be much more visible. I've seen this during multiple events, including an amazing "black" funnel from a long distance in eastern NM after a wildfire.

 

[Jason N]

Does anyone have any good analogs on good chasing years during El Nino transitions into Neutral (MAM / AMJ) readily available from possible past conversations on this question? ... I'd rather not duplicate effort just yet lol

 

[Mark Gressman Jr]

@Jason N - Not sure if this is helpful to you, and I haven't had a chance to watch it myself, but Convective Chronicles has another forecast vid out. I was really impressed with last years video, and it seems he has a few analogs he touches on this year as well.

 

[Jason N]

Hey Thanks Mark, I hadn't looked on his channel in a bit. This is great

 

[adlyons]

Some that I've been investigating are 2010 2003 1998 1995 1973 and 1966 for the more modern ones. Some older ones that are also similar fits.

 

[adlyons]

Here are the new CPC outlooka for MAM

 

[Brett Roberts]

Does anyone have any good analogs on good chasing years during El Nino transitions into Neutral (MAM / AMJ) readily available from possible past conversations on this question? ... I'd rather not duplicate effort just yet lol

The ENSO trajectory from moderate-to-strong winter Nino toward neutral during the spring is my personal favorite for the Plains, for the simple reason that it's been reliable in a way no other general category has over the past 30 years.

If we're looking for spring transitions out of Nino events which peaked with an ONI of at least ~1.0°C, here are the cases this century thus far:

2019
2016
2010
2007
2003

I would argue every one of those had a better-than-average Plains chase season, by modern standards, with 2010 being an all-time great season. And crucially, all except 2003 had above-average winter-to-spring precipitation across most of the southern and central Plains, meaning that drought and overmixing were rarely or never a hindrance to chase setups.

Conversely, my least favorite ENSO trajectory is when we languish around neutral or weakly cool throughout the spring, possibly nudging toward a nascent Nino by mid-late summer. Several of the most horrific chase seasons in recent memory fit that profile. Last year worried me early on, but ended up pushing into Nino territory early and fiercely, and it turned out to be a pretty good season overall.

Of course, the problem here is that even ~30 years is still a really small sample size, when one considers the diversity of possible ENSO trajectories and the ways in which other global climate features can interact with them. You can look back further into the 20th century and find results that differ quite a bit from everything I just said, but the global climate base state has changed enough over the decades that I wonder how relevant that is.

Nonetheless, as someone who's chased since 2006 and has seen every year with 2024's general ENSO trajectory turn out quite well, I'm cautiously pumped. In my mind, the distribution implied by the small sample of years we have to work with suggests a "good" season for the southern-central Plains is more likely than a "bad" season... even if confidence is low enough that a somewhat "bad" year wouldn't be totally shocking. The relative glut of winter precipitation for most of the Plains bolsters that.

 

[adlyons]

The ENSO trajectory from moderate-to-strong winter Nino toward neutral during the spring is my personal favorite for the Plains, for the simple reason that it's been reliable in a way no other general category has over the past 30 years.

If we're looking for spring transitions out of Nino events which peaked with an ONI of at least ~1.0°C, here are the cases this century thus far:

2019
2016
2010
2007
2003

I would argue every one of those had a better-than-average Plains chase season, by modern standards, with 2010 being an all-time great season. And crucially, all except 2003 had above-average winter-to-spring precipitation across most of the southern and central Plains, meaning that drought and overmixing were rarely or never a hindrance to chase setups.

Conversely, my least favorite ENSO trajectory is when we languish around neutral or weakly cool throughout the spring, possibly nudging toward a nascent Nino by mid-late summer. Several of the most horrific chase seasons in recent memory fit that profile. Last year worried me early on, but ended up pushing into Nino territory early and fiercely, and it turned out to be a pretty good season overall.

Of course, the problem here is that even ~30 years is still a really small sample size, when one considers the diversity of possible ENSO trajectories and the ways in which other global climate features can interact with them. You can look back further into the 20th century and find results that differ quite a bit from everything I just said, but the global climate base state has changed enough over the decades that I wonder how relevant that is.

Nonetheless, as someone who's chased since 2006 and has seen every year with 2024's general ENSO trajectory turn out quite well, I'm cautiously pumped. In my mind, the distribution implied by the small sample of years we have to work with suggests a "good" season for the southern-central Plains is more likely than a "bad" season... even if confidence is low enough that a somewhat "bad" year wouldn't be totally shocking. The relative glut of winter precipitation for most of the Plains bolsters that.

Great stuff as always Brett! I especially like your comment about the abundant early-season precipitation. I agree, things are trending toward a better-than-not year with more positive signs than bad ones like the past. Lets hope it stays that way!

 

[Matt Zumbrunn]

@Jason N - Not sure if this is helpful to you, and I haven't had a chance to watch it myself, but Convective Chronicles has another forecast vid out. I was really impressed with last years video, and it seems he has a few analogs he touches on this year as well.

I really like Convective Chronicles. He has some great tutorial videos I like. And I really like his case studies on some historical events.

 

[Jason N]

Of course, the problem here is that even ~30 years is still a really small sample size, when one considers the diversity of possible ENSO trajectories and the ways in which other global climate features can interact with them. You can look back further into the 20th century and find results that differ quite a bit from everything I just said, but the global climate base state has changed enough over the decades that I wonder how relevant that is.

Brett,

that was a great post, thanks for sharing it. Particularly the portion above is what really interests me in how we assess analogs of ENSO swaps, to predicatively look for correct balances of MJO phase and AO/PNO/NAO variances to align to a favorable pattern. I think it would be an interesting area of study to look at the shape/strength of the 5 Wave and associated Oscillation patterns+/-Phases during each of those analog years you mentioned. Perhaps see some kind of notional pattern emerges for each 3-month period, (MAM/AMJ), then see what the SST's were like in the Gulf. I don't know if that seems reasonable or not as a thought experiment, or useful?

 

[adlyons]

Quick update as we are now Mid march (crazy how fast time is moving!) We had a couple day stretch with some active weather in the Plains Midwest and parts of the Southeast. Congrats to those that scored storms! Looking at the reports thus far the forecast is on track. We are near to slightly below normal on LSRs so far this year.

That looks to continue after this most recent stretch. GEFS and other ensembles are showing a pretty unfavorable looking pattern through the next several weeks. This matches with some of the forecasts for a sudden stratospheric warming event that came to be in the first week of the month. Northeast US troughing should kep moisture offshore while higher lattitude blocking keeps the storm track supressed south and west.

And sure enough looking at some other tools, the GEFS chicklets are pretty barren with the average memeber sugegsting a -1 sigma for SCP.

So, its looking pretty quiet but relatively mild for the next few weeks. Probably a good time to start messing with the garden and finishing prep for the coming season. Seasonal models are still favoring an increase in return flow toward the end of the month into early April. Also im still seeing a lot of good signs for May.

 

[Mike Smith]

While I don't think we have consistent skill beyond seven days for any type of forecast, I wish to point out the ECMWF ENS is completely different from the GFS ENS. Of course, I'm not a fan of the GFS and almost never look at it.

 

[Warren Faidley]

Still bone dry out west. A lot can change change in 30-45 days, but "El Ninõ" is not cranking it out like expected. Neither the GFS or ECMWF show much in precipitation accumulations over the driest regions for the next 10+ days. Hopefully, we will avoid another "dust" year where visibility is cut throughout the alley.

 

[Ben Sainsbury]

CFSv2 precipitation anomalies remain pretty remarkable, particularly for May and June.

 

[Jason N]

Still bone dry out west. A lot can change change in 30-45 days, but "El Ninõ" is not cranking it out like expected. Neither the GFS or ECMWF show much in precipitation accumulations over the driest regions for the next 10+ days. Hopefully, we will avoid another "dust" year where visibility is cut throughout the alley.


View attachment 24620

I wonder how this will look over next few weeks with the recent cut off low and next 2 systems expected to provide some decent snows across AZ/NM.. will you repost this in a couple weeks? it will be interesting to look back on this image here.

 

[Warren Faidley]

I wonder how this will look over next few weeks with the recent cut off low and next 2 systems expected to provide some decent snows across AZ/NM.. will you repost this in a couple weeks? it will be interesting to look back on this image here.

The problem with Pacific configurations this time of year for SW weather is that they generally bring their own RH, which is **usually** not all that impressive by the time it reaches the E-NM and W-TX areas. It really takes the GoM influx in April to bring heavy rains. I'm not too concerned unless the end of April is still bone dry. I've seen dry conditions vanish quickly if there is a good pull of Gulf RH northwestward leading to steady or heavy precipitation.

 

[Mike Smith]

I just got finished looking at today's 12Z ECMWF and UKMET and, wow, for this weekend,

The ECMWF has SVR in the warm section and heavy snow in the cold sector. Surface pressure over Kansas Sunday is down 982. The ECMWF usually has a northward bias in situations like these.

While this is way too soon to get specific, I believe there is a good chance of SVR this weekend.

 

[Andy Wehrle]

I just got finished looking at today's 12Z ECMWF and UKMET and, wow, for this weekend,

The ECMWF has SVR in the warm section and heavy snow in the cold sector. Surface pressure over Kansas Sunday is down 982. The ECMWF usually has a northward bias in situations like these.

While this is way too soon to get specific, I believe there is a good chance of SVR this weekend.

We can delve more into this in Target Area threads as needed, but I'm seeing pretty consistent moisture problems for this weekend/early next week, with both GFS and Euro-AIFS depicting a low spinning up in the Gulf that moves up the East Coast late this week into the weekend, with its associated cold front scouring out the Gulf and leaving only a couple of days for partial recovery ahead of the system early next week.

Moisture issues are obviously not unheard of this time of year, and I've already been surprised multiple times just in the last two years by how low of a dewpoint in which significant tornadoes can occur (low 50s for Winterset 2022, mid-to-upper[at best] 40s for Evansville, WI last month). Just one of those flies in the ointment that will go a long way toward determining the ceiling of the setup.