Central/Western Medium-Long Range Discussion

[andyhb]

This year is very much reminding me of those insanely quiet periods between 1985 and 1988 where flow across the US just generally died in peak season. Poleward displaced Pacific jet is the main culprit of this, and that doesn't look to change anytime soon.

[Quincy]

The long range ensemble guidance isn't very impressive either. Just because there's some subtle troughing over the West Cosst doesn't mean much. That's late May climo. The difference this go around is that almost all guidance shows positive height anomalies over the Plains in late May, or in other words, shades of death ridge himself. 

Even though the overall pattern looks less-than-optimal, the fact that some troughing is modeled in the West suggests at least some shortwaves should be able to impinge on the High Plains. Maybe we don't get a big trough or an otherwise intense sequence, but with time, some of the key ingredients (particularly boundary layer moisture) will almost undoubtedly be there.

As Andy mentioned, upper level flow looks weak, at least for the next 7-10 days. Troughing continues over Hudson Bay with plenty of robust jet streaks targeting the Great Lakes. Since the northeastern portion of the U.S. generally sees most of their higher-end severe weather events under a northwest flow regime, maybe they'll squeak out a big event or two?

One can live and die by each model run, but it's healthy to take a step back. I've actually cut back how much I look at long range data, knowing that it will change a lot and late May to early June climo says that even the worst years see at least some noteworthy activity in the period. 

Still, it would be ignoring the data to refute the fact that trends are becoming less encouraging for the next 7-10 days, at least...

[WhiteoutWX]

This is mostly in jest, but when the long range GFS has been consistently showing hurricane landfalls in the gulf in May you know the overall pattern is total crap. 

[Quincy]

This year has been comical. April was one of the coldest on record for parts of the country and now we're almost literally jumping right ahead to summer. #2018ing

Quote from the latest SPC day 1 outlook: 

Quote

"WHILE THE OVERALL SYNOPTIC PATTERN IS MORE TYPICAL OF MID-LATE JUNE, BOUNDARY-LAYER MOISTURE IS NOT OF SUMMERTIME QUALITY"

 

[Torchageddon]

I really don't want to hear any hints of death ridge when it comes to the Plains in late May (Only over the GL ). I really need to take the advice of  cutting back how much I look at long range data, certainly not good to drive myself crazy. I'm going to look back to see what the mood was like at this time for May 2013 and 2016.

[Chinook]

This year seems to be following the pattern of some of the recent years, like 2013-2016. There seem to be less chaseable tornadoes, and less severe weather overall. I wonder if somehow this relates to the mid 80's (1983-1988 ??) when tornado numbers were low. I heard that Howie Bluestein and Chuck Doswell were bored, no storms to chase.

[Torchageddon]

9 minutes ago, Chinook said:

This year seems to be following the pattern of some of the recent years, like 2013-2016. There seem to be less chaseable tornadoes, and less severe weather overall. I wonder if somehow this relates to the mid 80's (1983-1988 ??) when tornado numbers were low. I heard that Howie Bluestein and Chuck Doswell were bored, no storms to chase.

You missed the most wretched year (May tornadoes) of all: 2017. Last year was truly appalling from an interest standpoint. All those High Risks and nothing memorable - this is my opinion alone but when I think 2017 for tornadoes the only tornado that comes to mind is the Canton TX one. With the 80s being what they were, what large scale configuration led to it? I think the quality severe was probably up north in the GLs because all sorts of stories originate from the mid-late 80s in ON.

[nrgjeff]

Ensembles have quieted down a bit. Choices ae force it in the next 10 days with a trough out West, but troubles in the East; or, wait for more subtle action toward Memorial Day into early June. At least last year we had the Total Eclipse to save a brutal chase year. Agree though, long range can and will probably change.

[Chinook]

12 minutes ago, Torchageddon said:

You missed the most wretched year (May tornadoes) of all: 2017. Last year was truly appalling from an interest standpoint. All those High Risks and nothing memorable - this is my opinion alone but when I think 2017 for tornadoes the only tornado that comes to mind is the Canton TX one. With the 80s being what they were, what large scale configuration led to it? I think the quality severe was probably up north in the GLs because all sorts of stories originate from the mid-late 80s in ON.

Last year did finish with near normal tornadoes for the US (1418 tornadoes), but the storm chasers on the Plains may have been quite unhappy with it.

Further information on tornado trends.

https://www.ncdc.noaa.gov/climate-information/extreme-events/us-tornado-climatology/trends

[CheeselandSkies]

GFS at around hour 156 doesn't look too terrible, if that shortwave in KS were a tad faster or the one in Iowa a tad slower. Still, it is frustrating not to see a broad belt of AOA 40kt SW flow overspreading that massive reservoir of instability.

[hlcater]

Well the primary jet really likes the northern conus and Canada, so I think sustained periods of AOA 40kts flow over the plains will be hard to come by. Thinking “day-of” events, upslope and boundaries are going to rule the 2nd half of may. However, with sufficient moisture and instability, this can work.

[Quincy]

This reminds me a bit of my days back in New England... When there was whispering of a "great" winter pattern setting up. The talk started in October, growing louder and louder into November. The conversation suddenly grew quiet, so much so that by the time March came and the ground was still brown, not a word was uttered about the winter that never came.

While the season is not over, we're at the all-star break, but our team had a painful first half. Batter after batter kept striking out. Prospects in the bullpen couldn't throw a solid inning, let alone a complete game, and the number of home runs hit, let's just say, were nearly a record low. Sure, not all games were lost and even a play or two made the highlight reel, assuming you were in the stands with a good view on that isolated day. However, we're most likely out of contention for the pennant and we're well below .500 for the year. Sure, there could be a historic late season comeback, but barring something like that, this will be a year that simply wasn't ours for the winning. 

Yes, things could change, but the trends are becoming increasingly less favorable. The silver lining (I feel like I've been saying this all year) is that even the worst years seem to have a masterful performance between late May and mid-June. Think back to 2014, when an epically bad Plains season was rescued in the 9th inning with two outs by hitters such as Pilger and Coleridge, seemingly out of nowhere. Recall 2017, a year that saw several highly anticipated games only fall short, sometimes painstakingly short, of expectations. Another 9th inning wonder came to bat when a rare Moderate Risk on the Front Range, of all places, actually performed and featured a few photogenic tornadoes. 

Another year that comes to mind is 2015. That year, overall, wasn't great and it was the first and only time that I strayed west of the Rockies during a late May trip to the Plains. I had a friend with me and after two abysmal chases in marginal setups, I did not want to disappoint her with a week of sunburn. It resulted in missing out on the Canadian day. The drive back was perhaps even harder, as I was not paying close attention on my way back east, ending up in Albuquerque one day, when I should have been in Dora...

We can all learn from seasons like this. My advice is don't live and die by the models with every breath. Forecasts change. Speaking again about my New England roots...some of the most memorable, major snowfalls were not anticipated more than a couple of days in advance. Sometimes a narrow band of snow, drawing parallels to a residual outflow boundary, waiting to be lit up, brought rush hour to a standstill as bystanders could only get out of their cars and look in awe. Likewise, magical tornadoes can spin out of seemingly marginal-looking environments. It is true that like snowstorms, some historic severe weather outbreaks can be well predicted, even as far as a week in advance. However, objective data tells us that beyond day 7, the skill of computer models becomes increasingly erratic, as extended model forecasts can and will change, sometimes drastically. 

In a way, I'm actually glad it's working out like this. I would rather have tempered expectations going into a below average stretch, than have hopes of fields of wedges obliterated morning convection and mammoth cap busts. The beauty of low expectations is that if the pattern does change, or if there is an unforeseen magical storm chase day, then it feels that much more special.

The bottom line... peak season is just about here and the models look pretty bad for the next week and as far as we can see with at least modest confidence, the signs are not encouraging. As a chaser, you have a few ways to look at this. Are you going to wait and hope that the pattern does change, allowing for a stellar finish to the season, or do you dial back to reality? Be ready, but flexible. Expect the unexpected. Prepare for the worst, but hope for the best. Stay optimistic, but don't be naive. You never know when the next MRGL or SLGT day could feature the storm chase of a lifetime.

[CheeselandSkies]

Even reading between the lines of Kerr's last few Day 4-8 convective outlooks, you can detect some degree of "WTF atmosphere, it's May?!"

Friday:

Quote

 While potential instability may contribute to areas with at least some risk for strong/severe
 thunderstorm development on a daily basis, there is little evident in model output to suggest an appreciable risk for a regional type
 severe weather event at this time.

Yesterday:

Quote

It also appears that the return of seasonably high boundary-layer moisture content off the Gulf of
 Mexico will continue to be hindered into at least early next weekend.  This currently seems likely to be a significant limiting
 factor to any severe weather potential across the central/southern Plains, which could accompany a short wave impulse emerging from the
 larger-scale Southwestern troughing next Friday/Saturday.

Today:

Quote

Otherwise, with seasonably strong mid/upper flow generally confined to a cyclonic swath southwest of Hudson Bay
through the eastern Canadian provinces and adjacent portions of the Northeast, severe thunderstorm potential across the U.S. seems
likely to remain relatively low for mid to late May.

 

[nrgjeff]

Baseball meteaphor is great. The 6-10 day is no longer wretched, and a come-back is possible. However mesoscale features must come together, which will be 12-36 hour forecasts. The 11-15 is not a total loss. Looks ridgy, but another trough with a couple short-waves might attempt. If heights do remain AN it will be a challenge. Manufacture runs, small ball, bunt 2%/5% (TOR) strong, and the season may still feature some fun.

[CheeselandSkies]

12 hours ago, Quincy said:

The bottom line... peak season is just about here and the models look pretty bad for the next week and as far as we can see with at least modest confidence, the signs are not encouraging. As a chaser, you have a few ways to look at this. Are you going to wait and hope that the pattern does change, allowing for a stellar finish to the season, or do you dial back to reality? Be ready, but flexible. Expect the unexpected. Prepare for the worst, but hope for the best. Stay optimistic, but don't be naive. You never know when the next MRGL or SLGT day could feature the storm chase of a lifetime.

Ah, but therein lies the problem for those of us who just don't have the luxury to chase all of them.

[jojo762]

Looking at the 12Z GFS/EURO/GEFS/EPS, the next couple weeks look like they could be mind numbingly boring with above average 500mb heights being forecast across much of the plains states through the period. With that said, as Quincy stated, mother nature will probably pull a rabbit out of a hat a time or two and surprise us at some point... Long-range guidance could quickly change and Late may could end up being big, as it has been in recent years, so stay tuned.

[CheeselandSkies]

Next weekend actually doesn't look entirely awful on the GFS, this morning's 12Z run had a 2-day play from KS to the Midwest on Saturday-Sunday. The surface pattern doesn't look stellar but at least there's 500mb flow above 30kt overlapping some instability.

[hlcater]

Guys! The ERTAF is showing some hope in the long range!

http://atlas.niu.edu/ertaf/

[Quincy]

40 minutes ago, hlcater said:

Guys! The ERTAF is showing some hope in the long range!

http://atlas.niu.edu/ertaf/

Last week, May 6-12, was a staggering 91% below climatology (based on preliminary reports) in terms of tornadoes with only six. The only such period that saw fewer since 1950 was four in 1987. 

[bjc0303]

21 minutes ago, Quincy said:

Last week, May 6-12, was a staggering 91% below climatology (based on preliminary reports) in terms of tornadoes with only six. The only such period that saw fewer since 1950 was four in 1987. 

Might be time to close the door on May and look ahead to June. Unfortunately for me I will be at a camp June 3-17 with no phone or internet lol. Send your pics to Maxwell AFB folks. 

[Torchageddon]

1 hour ago, hlcater said:

Guys! The ERTAF is showing some hope in the long range!

http://atlas.niu.edu/ertaf/

I'm getting the opposite of hopefulness from looking at ERTAF: "A continued northward shift in the NPJ leads us to believe the peak of annual US tornado frequency in the Great Plains (weeks 2 and 3) will be gravely below average."

[andyhb]

I can sense the annoyance/boredom both in that and even in the SPC outlooks recently.

[largetornado]

This nugget in the D4-8 outlook.....

[nrgjeff]

While it appears May will lack a big outbreak, I see at least two chase sequences in the next 10 days. Thu-Sat could go from the Front Range to KCMO, with Friday the best day in between. Middle of next week evidence is increasing for another meandering short-wave. It might have better moisture without this Tenn. Valley bowling ball. Hudson Bay low, which clearly hostile, I think is less of a factor than this asinine bowling ball.

ERTAF is depressing, but even BA in late May is not a deal killer if one has time and freedom to sniff out mesoscale features. SPC is clearly frustrated, a rare if subtle show of emotion. Those mets are there because the love severe weather. SPC mets are disgusted with this pattern too. On the other hand, when they say "relative to late May" I think they leave the door open for severe. I'm also slightly surprised they go Potential.. instead of Predictability...

Enough of the psychology, we still have WSW flow over the Plains. Moisture is a question later this week, but I can deal with JIT (just-in-time moisture) in late May relative to before May 15. Middle of next week agreement on a short-wave is there. Day 10 details can/will change. Moisture may be JIT again, but looks slightly better. Also climo. No outbreaks, but I think 3-5 chase days will happen in the next 10. Might just be 5%, but doable. From The Martian: Might have to science the sh!t out of this!

[CheeselandSkies]

31 minutes ago, largetornado said:

This nugget in the D4-8 outlook.....

They had that in there yesterday, too (same forecaster IIRC). GFS continues to look at least moderately interesting over NC/NE KS for next Saturday, so I'm surprised they didn't at least throw in a "predictability too low" for that. Yeah there is some 700-500mb VBV in here but decent turning below 700mb and very strong instability.

[andyhb]

Lol @ not being able to get 40 kts of flow at 500 mb in f*cking May.

[CheeselandSkies]

14 minutes ago, andyhb said:

Lol @ not being able to get 40 kts of flow at 500 mb in f*cking May.

I hear that. Of course, I said the same thing for the days of Dodge City and Chapman that one week in 2016. I was laser-focused on that Thursday and...yeah.

The problem for me is that those days, by themselves, looking as they did even 2 days out wouldn't be enough to get me from WI to western KS, even if I had been off that week.

[largetornado]

30 minutes ago, andyhb said:

Lol @ not being able to get 40 kts of flow at 500 mb in f*cking May.

Legit question...Will we even see 600 tornadoes this year? At 320ish now. 

[hlcater]

5 hours ago, largetornado said:

Legit question...Will we even see 600 tornadoes this year? At 320ish now. 

Probably. We aren’t at record lows(yet) and still have the rest of may, June and July to go. Shots at 1000 closing fast. Best guess I have right now is 800-900

[Quincy]

3 hours ago, hlcater said:

Probably. We aren’t at record lows(yet) and still have the rest of may, June and July to go. Shots at 1000 closing fast. Best guess I have right now is 800-900

Assuming we're near 320 right now and we finish May with only 323 (3 more tornadoes!), following 1991-2010 climo for the rest of the year would put us right at 1000. However, it doesn't quite work that well, as I mentioned earlier in the year, more than 50% of years and months finish with below "average" tornado counts. It's the big events/outbreaks/seasons that skew the average a bit higher.

At some point, you do have to consider persistence and I do think if there was a year to finish with less than 1000, it was this year. We managed to pull off the feat in 2016, but peak season was fairly active that year. We also did it in 2013, but the second half of May was fairly active. I guess that speaks volumes, as if we stay slow, it's going to be that much harder to dig out of the hole.

If things don't turn around in the next few weeks, this might be an even worse version of 2013. Imagine if 2013 was slow in May and didn't have November 17th, that's about as bad as it can possibly get...