State of the Chase Season: 2019

[JamesCaruso]

I never want to see an active March. I can't think of too many seasons in the last 20 years featuring *both* an active March *and* an active May-June. I don't believe the synoptic scale pattern ever maintains itself long enough to be active from March all the way through June.

It's too early to speculate about the overall quality of the season. Surely by mid-April we will start to see how the early part of the main season will go.

I remember you commenting on this last year Jeff; in somewhat of a post-mortem on the season you noted how many troughs there had been in March (maybe April too, I can’t remember). My takeaway, in crude terms, was that the atmosphere had sort of “used up” its allotment of troughs by the time the heat and moisture of spring arrived.

Anecdotally, any year that I saw a lot of early activity I always worried that I was going to miss out on the action by the time I got out there in mid to late May. So I, too, am relieved to see an inactive March, but how do you view April? Is it that you like to see the same low activity in early April as in March, but then want to see an active late April? Or do you look for the month of April overall to be a Goldilocks month, when the ideal is not too much and not too little?

 

[Jeff Duda]

Anecdotally, any year that I saw a lot of early activity I always worried that I was going to miss out on the action by the time I got out there in mid to late May. So I, too, am relieved to see an inactive March, but how do you view April? Is it that you like to see the same low activity in early April as in March, but then want to see an active late April? Or do you look for the month of April overall to be a Goldilocks month, when the ideal is not too much and not too little?

I think there are some potential signals for an analogy to 2015. Weak El Nino going in. A tendency for a wetter period to begin (although there was still widespread severe drought across the southern Plains leading into the 2015 chase season, but it ended up being OKC's wettest May ever). Active subtropical jet.

April 2015 was pretty active, and I chased a lot, although I missed all of the tornadoes in that month. May was where it was at, but it was grungy for sure.

Provided we don't continue to see the TPV persist well into April (it is currently persisting in the NE CONUS and across the Hudson Bay area) throwing cold surges clear down to the Gulf, I think there's a pretty good chance of an active April.

 

[Andy Wehrle]

I think there are some potential signals for an analogy to 2015. Weak El Nino going in. A tendency for a wetter period to begin (although there was still widespread severe drought across the southern Plains leading into the 2015 chase season, but it ended up being OKC's wettest May ever). Active subtropical jet.

April 2015 was pretty active, and I chased a lot, although I missed all of the tornadoes in that month. May was where it was at, but it was grungy for sure.

Provided we don't continue to see the TPV persist well into April (it is currently persisting in the NE CONUS and across the Hudson Bay area) throwing cold surges clear down to the Gulf, I think there's a pretty good chance of an active April.

Yeah, I would have thought we'd be done with the polar vortex problems by now since we did not have a late winter SSWE like last year (whew) and we had our mid-March thaw on time here in the Upper Midwest, which of course had led to all the flooding problems.

 

[Andy Wehrle]

Anyone have any updated thoughts? I've heard rumblings April might not be as hot as originally thought earlier in March. GFS has been all over the place in the medium to long range as usual. At times it teases some good looking western troughs/systems at 240+ hours and even keeps them for a few consecutive runs, but so far they've all deteriorated as they've gotten closer.

The good news is, even the fantasy end of the GFS still only reaches out to mid-April, and barring something crazy and unforeseen it doesn't look like we will be faced with anything like the extreme delayed spring of last year.

 

[Dan Robinson]

IMO nothing on the horizon yet. The Gulf is finally showing some signs of life (widespread 70s DPs) in a week or so, but not much of it making its way north. Add to that at least one Gulf-scouring front hinted at after one of next week's waves. GEFS ensembles show an active southern stream jet, but too far south for any Plains action. That will also help prevent Gulf moisture return to chaseable latitudes. There are some narrow ribbons of moisture that poke north of I-40 now and then, but only good for lightning/hail and some high-based supercells. Maybe some Dixie ops with the active jet down there, but not much in the Plains and Midwest.

 

[Jeff House]

I live in Dixie and would rather just wait for the Plains, lol! Agree with Dan above the pattern may remain somewhat/seasonably active in Dixie; but, probably not for major outbreaks (fortunately). That TPV should prevent classic Dixie outbreaks.

MJO is currently a disaster for storm chasing. Downstream effects show up with the TPV and inability to hold a West trough. Still there's hope with progressive troughs. Ask people who skied out West recently. Probably keep getting Slights in the Plains.

West Coast SSTs have warmed again the last 7 days, including down near the Baja, bad for chasing. MJO convection is in an awful phase. Hopefully all this is associated with current / mid-term KWs, and not a long-term debacle for chasing.

I'd rather have crap MJO phases in April and recover in May. Risk is March was another head-fake into a slow season. My optimism has faded sharply since last post. However it's early. Peak of the season is still six weeks away. Weekly forecasts are worthless past week 3; so, anything can happen in May.

 

[Jeff Duda]

According to the folks running their seasonal ERTAF experiments at NIU, expect below average tornado numbers for the next few weeks: http://atlas.niu.edu/ertaf/

 

[Jesse Risley]

According to the folks running their seasonal ERTAF experiments at NIU, expect below average tornado numbers for the next few weeks: http://atlas.niu.edu/ertaf/

I saw a tweet from Victor about a week or two ago that made some more detailed comparisons of how this pattern is quite similar to 2013 so far. That year didn't see much activity materialize until mid to late May.

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[V. Gensini]

All the calls for a hot April were hot air. We were the only forecast I've seen that suggested a poor start to the severe season due to split flow and high AAM base state. You have to remember that even the ensembles do not have severe skill beyond ~10 days: https://agupubs.onlinelibrary.wiley.com/doi/epdf/10.1029/2018GL081724

Dynamical forecasts are not going to get you where you want to be if interested in week 2, 3, or beyond. This pattern resembles 2013 and given GSDM stage 2 and convection anchored just west of the IDL, I don't see much of any forecast of opportunity in re: to a jet extension or collapse. If you play the dangerous linear extrapolation game, things won't "align" again until roughly the first/second week in May. We need a flare of IO convection associated with the Asian Monsoon to get the MJO moving again, and that likely will not happen until early-mid May.

 

[Trey Thee]

I saw a tweet from Victor about a week or two ago that made some more detailed comparisons of how this pattern is quite similar to 2013 so far. That year didn't see much activity materialize until mid to late May.

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Excellent point. I recall 2013 being fairly slow, seems like only a couple chases prior to the mid-May ramp up in activity. Would like to see activity perhaps a bit more spread out through May and let's avoid the F5 in a metro area please. Best course in my opinion has always been to generally focus on what models are showing within 7 days time. As Gensini mentioned above things get dicey out beyond 10 days and really is a roll of the dice.

 

[Jeff House]

Even if the next 2-3 weeks are quiet, I do not understand all the gnashing of teeth. Yes my own optimism has faded, but at the same time I have no reason to think below climo in May.

As a vacationer, not local anymore (I'm homesick each spring), I do not think about April much anyway. May is my only concern. Little forecast skill exists past week 3, until the seasonal level. May is in that in-between spot. No reason to be bullish; but, also no reason to be bearish.

 

[Quincy Vagell]

I wouldn’t get hung up past week 3 either. I know many have pre-planned chasecations, but a lot can change. Even just a few days out, patterns can find a way of producing. I found that out the hard way in 2015. Peak climo produces too and only time will tell how active May and June will be this year. Have patience and remain cautiously optimistic!

 

[Todd Lemery]

I never expect multi day chasing until May and then only decide to go or no go 2-4 days ahead time anyway. My only concern is that I have to be more picky this year about the setups I choose to travel down and chase for. I really blew through my time off last year while chasing and failed spectacularly at the same time. If I run out of time off I may have to figure out how to break a leg or something. P.S. If my boss is reading this I am joking....

 

[Marc R. O'Leary]

Even if the next 2-3 weeks are quiet, I do not understand all the gnashing of teeth. Yes my own optimism has faded, but at the same time I have no reason to think below climo in May.

As a vacationer, not local anymore (I'm homesick each spring), I do not think about April much anyway. May is my only concern. Little forecast skill exists past week 3, until the seasonal level. May is in that in-between spot. No reason to be bullish; but, also no reason to be bearish.

I don't care when it happens or where it happens, I just want to see something happen. Lightning, awesome. Tornado, cool. Just give me something to go hunt down and watch.

 

[Andy Wehrle]

Looks like the usual April problem upcoming of when the pattern does turn active, the systems are too close together to allow for decent moisture return between them.

Yet again...cross our fingers and wait for May.

 

[NickL]

One observation i can make is that soils and aquifers in kansas are literally bursting with water, small creeks and runs that rarely or never flow consistently have had constant flow for months. We had a very wet late summer through now. I haven't seen this type of saturation, this time of year in the last 15 years. Take from that what you will. Less mixing? beter evapotranspiration? none of it matters though if the large scale jet stream pattern isn't favorable in the spring

A fair number of rivers in western Kansas and especially southwestern Kansas are still bone dry. East of that, I agree rivers are flowing like I havent seen in many years.

 

[samuel stone]

A fair number of rivers in western Kansas and especially southwestern Kansas are still bone dry. East of that, I agree rivers are flowing like I havent seen in many years.

Alot of streams in western kansas are quite ephemeral. Many that are, have had much more flow than normal for the past 8 months. Generally speaking western Kansas streams just don't have the alluvial aquifers capable of sustaining flow given precipitaiton of 16 to 20 inches per year and very porous soils/underlying geologic bedrock. most of western kansas is topped by holocene loess or sand, and underlain by pliocene sand and gravel of the ogallala formation. Streamflows in that part of the state are not very indicative of the regions overall top soil moisture. I have a degree in geology from Kansas State btw.

Streams and rivers in central and eastern Kansas have been running high largely speaking for the past 8 months. and alluvial as well as perched aquifers have been producing water like i haven't seen.

That being said, we have been drying out a bit precipitation wise through late march.

 

[Marshall Stoner]

It's still a ways out, but the latest GFS is showing a 776 mb low wrapping up over the plains next week. It's showing a crazy bent-back occluded front with lots of helicity possible in and around the triple point both Wednestay evening somewhere over Nebraska then again Thursday evening over Illinois. The amount of instability and cap strength is kinda a question mark though it would seem, as is the exact track. GRR weather discussion yesterday was saying the ensembles were all over the place with the strength/track of this low though. Seems like the confidence in a stronger system has increased today, but I don't know how much. Anyone want to fill me in?

 

[Todd Lemery]

I’ll believe when NAM verifies. NAM is up to Wednesday now and it does look like the wind profiles will be favorable. I’m crossing my fingers that decent moisture will make it that far North. We’ll have a pretty good idea in a day or two...

 

[Marshall Stoner]

Right now it looks like most of the plains will be capped and dry-ish with this system, but maybe a narrow line of supercells will develop in the evening. Illinois and Indiana the next day looks kinda of interesting though. Also another massive blizzard for the upper plains. Gotta feel sorry for those folks.

 

[Ethan Schisler]

00z NAM tonight shows the most favorable outcome so far I've seen (not saying I buy it) for Wednesday. A 70 knot jet streak at 500mb is passing through the KS/NE region around 00z Wednesday evening and CAMs show initiation taking place between 21-00z and storms up and down the dry line toward evening. The same model only shows a very narrow corridor where CIN is low enough to maintain a surface based storm, which is highly suspect. If we can get storm imitation anywhere the CIN isn't particularly high, co-alligning with the best surface convegence, especially near the triple point, I definitely think there could be a tornado threat. Highly conditional, but its April, so best keep our eyes peeled. I'll wait for another day to create a thread or if someone beats me to it

 

[Marshall Stoner]

It looks like a cap bust on the plains. Then the storm is filling when the warm sector finally reaches Illinois/Indiana, so isallobaric compenent isn't favorable for sufficiently backed low levels there, plus weak instability. NAM has the warm front getting into Michigan but every NWS discussion thinks its full of shit. lol Was really hoping for an Illinois / Indiana chase. Maybe the next system will be better. Who knows.

 

[Warren Faidley]

For the sake of the chase season, I hope the models are wrong.

 

[Quincy Vagell]

That is pretty remarkable that the CFS is so tame, even out into mid-May. Sure, it doesn't have much usefulness past 2-3 weeks, in my experience, but it's actually trending away from climatology in the long range. I'm not sure I can explain that, but regardless, you will have better verification going with climatology than the CFS in the 4-6 week range.

 

[JamesCaruso]

I was feeling nervous about having such a late chase vacation this year (starting 5/24), but I feel better about it after seeing that CFS.

5/24 will be the very next column that appears on the model today...