May 012016
 

Sunday 1 May, 2016

It’s interesting being both a meteorologist and a storm chaser. I mean, the whole reason I ever wanted to pursue a degree in meteorology in the first place was driven by a passion for severe weather. It’s something that was always in my DNA, and triggered anytime I saw a thunderstorm as a kid. So I always knew I would end up studying weather in some capacity as an adult. And what drove that home was an intense fascination with tornadoes. As a young child, I remember my grandparents would talk about having tornado warnings from bad storms in Illinois. I never saw any pictures or video, so my imagination would go wild. It wasn’t until I was almost a teenager that I saw actual footage of a tornado from a TV special. I just wanted to see one myself. But rooted within that desire was also an interest in how tornadoes form.

Supercell
Image above: Gust front on a supercell from April 29, 2003 in northwest Kansas near the Nebraska border. (Photo by Jim Bishop)

I spent years studying tornadoes while at the University of Oklahoma. And this wasn’t just in the classroom – I chose to independently (along with Simon Brewer and Tom Santillo) go storm chasing. And storm chasing back then wasn’t easy, and neither was forecasting! It’s funny to think what storm chasing and forecasting was like back then, and what little I knew then compared to what I know now. At any rate, throughout my college career, I learned how to apply my knowledge from the classroom into the field. I had become an experienced storm chaser, a forecaster and meteorologist.

But every spring there were always the same questions. When will the pattern become active? Is a death ridge going to develop and put an early end to the chase season? When will the Gulf moisture return to the southern plains? This is where climate science and meteorology begin to converge, and it’s an area of study I didn’t know I would get into. It really wasn’t a focus after graduating from OU. My focus was getting a job forecasting the weather, and going storm chasing in the spring.

I ended up in a career in the energy industry, where I’ve spent the last twelve years forecasting medium and long range weather patterns. I sorta fell backwards into a field of climate science mixed with all the short term, day to day weather forecasting you would expect from any degreed meteorologist. But it’s very interesting as a storm chaser to spend so much time studying and forecasting weather patterns, because it gives me the ability (at least to a degree) to forecast weather patterns conducive to producing tornadoes across the U.S.

Living in Boston, about as far away as you can get from the Great Plains while still living in the U.S., I have to take storm chasing trips to see tornadoes. There are two ways to go about this. The first way is the most obvious – plan a vacation. You pick the dates, request the time off of work, etc., and when the time comes you go storm chasing. The one major downside to that is you are 100% at the mercy of the prevailing weather pattern. If the patter is quiet, you’re out there making the best of it. The upside is you were probably able to make this vacation budget friendly.

The second way is more difficult to implement, and it’s called spot chasing. Basically, when you see a series of 2-3 good setups, go storm chasing. You end up paying a premium for a plane ticket, but you are not out there for that long and you are much more likely to see a tornado. Of course, if you are not familiar with the current state of the weather pattern, you might get suckered into going chasing by favorable looking setups on the computer models, only to see the setups look much less favorable as the event draws closer. So how do you about spot chasing?

Rozel Tornado
Image above: Jim Bishop shooting video of the Rozel, Kansas tornado on May 18, 2013. (Image by Simon Brewer)

I’ve found having an understanding of how the weather pattern is likely to evolve over the course of the month can be very useful in choosing when to go storm chasing. And it’s funny saying that now, because back in the early days of my storm chasing career, I was at the mercy of a single medium range computer model and the setups it would forecast over the next ten days or so. At the beginning of May, even if nothing looked favorable for severe storms for the next ten days, there was still plenty of hope being early in the chase season. It wasn’t until the calendar turned to early June that we would become concerned the season might be over soon if not much had happened yet. We were basically chasing in a day to day, week to week type of outlook with open wonder in the weeks beyond that.

At any rate, it’s just interesting to me that today I apply what I’ve learned while forecasting medium and even long term weather patterns (climate), to storm chasing. Every year by the early spring I find myself diagnosing the ocean-atmosphere system (El Nino, La Nina) for clues as to when the weather pattern will become active for storm chasing. And when you have an understanding of how the pattern should evolve or how it should act, you should be able to pick a good time to find tornadoes. Or at least, that’s the best I can do right now!

Supercell
Image above: Two supercells off in the distance over southern Kansas on April 17, 2002.

So cutting to the chase (no pun intended), our current ocean-atmosphere system remains complex. I guess if it wasn’t, this blog post would have gone a different direction! But we still have El Nino forcing over the western Pacific, despite the fact that it does appear we will see the demise of El Nino later this month (there are numerous indications we will be in a La Nina this summer). Nevertheless, there are small atmospheric waves over the western Pacific, interfering with a new MJO (Madden-Julian Oscillation) signal over the Indian Ocean. This interference is one of the reasons why we keep getting cold fronts over the eastern U.S., closed upper lows over the Southwest to Plains, and why the pattern won’t be conducive for numerous severe storm setups (particularly tornadoes) over the next several days. We should see a significant closed upper low the weekend of May 7 over the plains, but low level moisture return will be a concern given the previously mentioned issues.

What I believe will occur, is the MJO will grow in intensity over the Indian Ocean over the next 10 days or so and progress slightly east. This usually sends a series of troughs into the southwestern U.S., and would promote a pattern conducive for severe storms and possibly tornadoes. But western/central Pacific tropical forcing (likely tied to the last gasp of El Nino as it fades) needs to go away. If that forcing weakens or dissipates (which is suggested by the European Weekly model), the warmer phases of the MJO will probably have more of an impact on the weather pattern and May 14 (ish) to May 25 (ish) should prove to be quite active for severe storms and tornadoes across the southern and central Great Plains of the U.S.

Jim

Apr 102016
 

April 10, 2016

We are getting into the time of year when severe storm frequency begins to increase across the Great Plains of the United States. Severe thunderstorm and tornado activity usually becomes more common in mid and late April, with a significant increase in May. This frequency can vary a bit from year to year of course, but meteorologists and storm chasers know very well the typical storm chasing season begins in late April and holds through late June.

After reading that, you might wonder why I’d write a blog post about the atmosphere gearing up for severe storms late in in April! Well, it’s true we would normally expect the pattern to bring at least some severe storms to the table in a few weeks. But in this particular case, it appears the atmosphere is quite literally getting ready to unleash the onset of the spring storm chasing season across the Great Plains!

Without getting too technical, I’ll mention a few weather pattern drivers. First on deck – the MJO (Madden-Julian Oscillation). The base, or background, state of the ocean-atmosphere system (or climate) is currently trying to transition from El Nino to La Nina. In doing so, thunderstorm activity across the tropical regions of the Indian Ocean and around Indonesia has recently increased. Now, this is not just because of a tendency towards La Nina or the slow decay of El Nino (El Nino is still a driver). Water temperatures across the Indian-Pacific sector are extremely warm (well above normal), which is making it very easy for thunderstorms to develop. On top of that, yes, we currently have a sub-seasonal decrease in Atmospheric Angular Momentum occurring, which (IMO) is the climate system trying to dip it’s first toe in the La Nina direction (probably the first of many).

Outgoing longwave radation (blue) over the past few days showing thunderstorm activity increasing over the Indian Ocean
Above Image -outgoing longwave radiation (blue) over the pas few days, showing thunderstorm activity increasing over the Indian Ocean.

With increased thunderstorms and other signals coming together over the next couple weeks, we will have the birth of a new MJO wave over the Indian Ocean. As this grows in strength, it will naturally propagate eastward towards Indonesia (phase 5). In late April and May, this sends the Pacific jet stream crashing into the southwestern U.S. And with the tendency towards a more La Nina like pattern, the MJO will be working with falling AAM to bring a series of troughs into the southeastern U.S. That kind of scenario is conducive for an active severe storm pattern across the Great Plains of the United States.

GWO
Above Image: Atmospheric Angular Momentum over the past ten days, and GFS Ensemble forecast as shown by the GWO.

The first response to the angular momentum dip will bring a couple days of severe storms to the Great Plains next weekend (April 16th) as indicated by medium range models. But there could be moisture issues, and it looks like we’ll be dealing with a close low. I think the more prolonged, potentially more significant severe storm pattern will unleash during the last week of April and perhaps leading into very early May.

I don’t want to bring up analog years or get too specific. But the way things are coming together reminds me of a couple different periods in the 2000s when severe storm/tornado outbreaks occurred across the central and southern Great Plains. We’ll have to watch how both the MJO and angular momentum evolved over the next one to two weeks before getting a better idea of this pattern evolution. But it certainly looks like storm chasing season is about to kick off in late April into very early May.

Jim

Apr 042016
 

April 4, 2016

It snowed today in Boston. It snowed quite heavily for several hours, a pretty rare event for April I must say. I took some photos around downtown Boston to document this event – in the financial district as well as around Boston Common. Despite the fact that snow in April just seems wrong, I got some shots that seemed to capture the moment.

Below are some of the photos.

Snow Picture

Snow Picture

Snow Picture

Snow Picture

Snow Picture

Snow Picture

Snow Picture

Snow Picture

Snow Picture

Snow Picture

Snow Picture

Aug 042015
 

Obviously, chasing in Boston isn’t the same as being out in the plains- road networks, trees and traffic make seeing storm structure nearly impossible. Despite that hindrance my wife and I were able to see the back side of a tornado-warned supercell from Saugus, MA looking to the northeast. The storm structure was gorgeous with mammatus clouds overhead and the sun shining through the storm itself.

Another storm, a supercell that was rapidly becoming outflow dominant (soon to be bow echo), was to our west heading east. We decided to drive southwest to intercept the storm in the Costco parking lot in Everett, but also to do some shopping as we waited for the bow echo to pass and make driving home a little more manageable. As we walked inside, you could hear tiny pops and crackles as hail began to fall. It began to rain as we walked into the entrance- and then it really began to hail in earnest, netting quarter sized hail. We were actually in a great spot to see all of this unfold- the entrance near the shopping carts- because we got hit with intense straight line winds which violently blew boxes and carts everywhere- people yelling and filming it with their phones. There was loud thunder and cloud-to-ground lightning strikes, making the area filled with people who aren’t really used to severe storms quite the chaotic scene. The employees had to quickly close the drawbridge doors to the front of the store, effectively locking us all inside as this happened. The whole ‘event’ lasted around ten minutes and then everyone went on their way- definitely an entertaining trip to Costco for everyone!

Storm

Lightning

Hail

Jun 132015
 

Saturday, June 13, 2015

As usual, it’s taken me longer than I would have hoped to put together a blog post with video captures of this chase. On May 7, 2015, I was storm chasing with Jesse Duncan alongside Simon Brewer and Juston Drake in another vehicle in north Texas. We ended up documenting numerous supercells ahead of a squall line. The final supercell produced several tornadoes which we documented near Bolivar, TX and surrounding areas. This was all in an area just to the northwest of Denton, TX.

Below is my footage from the chase.

The following are screen captures taken from my footage.

Tornado

Tornado

Tornado

Tornado

This is a satellite rope tornado that developed briefly to the right of the mulit-vortex wedge tornado.

Tornado

Tornado

Multi-vortex wedge tornado.

Tornado

Tornado

Tornado

It’s hard to see due to the contrast. But, there is a white, cone tornado on the ground just to the right of the road.

Tornado

Tail cloud feeding into a large wall cloud and wedge tornado.

Tornado

Tornado

Tornado

The parent tornadic circulation, which remained multi-vortex in nature for quite some time, produced numerous quick ‘spin-ups’ like the one in this shot.

Tornado

Wedge tornado.

Tornado

Tornado

Tornado

Tornado

A spectacular shot of the wedge tornado and wall cloud, with a visible ‘clear slot’ to the left, or rear flank drowndraft. This depicts classic supercell structure and likely marks the peak intensity of this supercell.

Tornado

Tornado

Tornado

Tornado

Tornado

Tornado

This is a screen shot taken from a farm road while re-positioning the vehicle. The tornado briefly become quite photogenic.

Tornado

Tornado

This is the last tornado we saw produced by this supercell. There was still a wedge on the ground to the north of this final tornado, but the wedge was wrapped in rain and very hard to see by this point.

Feb 112015
 

Wednesday, February 11, 2015

We just keep getting more and more snow. So, I’ve tried to capture what the city of Boston looks like while being taken over by a seemingly endless parade of heavy snow and high winds.

Some of these photos were taken before the most recent nor’easter that occurred Monday, February 9. Others were shot directly after the additional 2 feet of snow we received from that storm. This has truly been an historic period, with some of the heaviest and the highest frequency of nor’easters and blizzards this city has seen in decades.

Boston Snow

Boston Snow

Boston Snow

Boston Snow

Boston Snow

Boston Snow

Boston Snow

Boston Snow

Boston Snow

Boston Snow

Boston Snow

Boston Snow

Boston Snow

Boston Snow

Boston Snow

Boston Snow

Boston Snow

Boston Snow

Boston Snow

Boston Snow

Boston Snow

Boston Snow

Boston Snow

Boston Snow

Boston Snow

Boston Snow

Boston Snow

Boston Snow

Feb 022015
 

February 2, 2015

Boston has been experiencing near blizzard conditions throughout the day today. The first wave of heavy snow and high winds came early in the morning, persisted for several hours, and finally settled down for a bit around lunch time. In the past couple hours this afternoon, heavy snow and high wind have picked up again with very low visibility. Locally, Boston has received nearly 10 inches of snow today with more snow accumulating by the second.

Below are a few photos I took when things downtown were a bit quieter between heavy snow bands and blizzard like conditions.

Boston Snow

Boston Snow

Boston Snow

Boston Snow

Boston Snow

Jan 272015
 

Tuesday, January 27 2015

Boston, along with much of New England, has been through a significant blizzard. I documented the storm in downtown Boston. As the storm strengthened in the early morning hours I experienced wind gusts to 50+ mph at times. You can view that footage below. Later, I took photos around the area and found several cars covered in snow. As of this writing, it is still snowing. I measured 17 inches of snow on a flat surface, with 2 feet of snow on many sidewalks, likely due to the snow drift.

Cars covered in snow

More vehicles covered in snow

Boston snow

Boston snow

Apr 192014
 

Saturday, 19 April 2014

 

Here we are just past the middle of April and the storm chasing season has been pretty slow. The exceptions have been a day or two of supercells from north Texas into Oklahoma, with a few tornado reports. But for the most part severe storm activity has been infrequent at best across much of the central U.S., including the Great Plains. In fact, over the past couple weeks snow has fallen from central Oklahoma to Kansas! And not only that, but Detroit, MI officially broke their season snowfall record. They recorded 94.9 inches of snow for the season, beating the old record of 93.6 inches set way back in 1880-81! So, winter has sorta hung on into mid April and the severe storm/chase season has been sitting in the back seat, waiting for its turn at the drivers seat. Well, things are starting to come together and the chase season may get in the drivers seat by the end of the month.

A couple weeks ago I addressed the beginning stages of a MJO wave over the Indian Ocean and the Indonesia region. At the time it appeared like two areas of tropical convection would come together and propagate east. It hasn’t been a classic wave and plenty of other things are going on across the northern hemisphere that are complicating matters. But, tropical convection has reached the international dateline/western Pacific, and things are being set into motion (see image below).

 

Outgoing longwave radiation over a 3 day period (April 15-17). Notice the negative values over the western Pacific indicating where tropical convection has reached the international dateline.

 

Notice the MJO had a weak projection into phase 6 but has since weakened further.

 

For those of us hoping for the severe storm activity to pick up across the Great Plains (and that’s many of us), then it’s unfortunate the tropical convective signal (MJO) is weakening. But the good news is some strong jet energy coming out of eastern Asia and the northern Pacific will work in conjunction with this MJO signal. What this means is something that’s already being set into motion. We will see a couple Pacific jet stream extensions, which we will see in the form of troughs slamming into the western U.S. The first of which will occur next week (Week of April 21) and should bring a day or two of severe storms across the Great Plains/central U.S. But the larger, more significant jet extension will occur a few days later in late April (you can already see that beginning stages of that jet extension over the western Pacific east of Japan right now, see image below). This is the jet extension that should bring a series of troughs (some significant) into the western states during the last week of April into early May. And if everything worked out perfectly, this would bring several days of storm chasing/severe storm setups to the Great Plains during that time.

 

Water vapor image centered on the western Pacific valid 2032z April 19, 2014. The red arrow outlines the Pacific jet feeding into a low pressure system east of Japan (red circle). This combination should eject eastward across the Pacific in the form of a powerful Pacific jet extension.


 

GEFS Reforecast (initialized 00z 4/18/2014) 500mb height anomalies valid April 26, 2014. Notice the deep trough over the eastern Pacific extending into the western U.S. The red arrow is there to outline the Pacific jet extension, essentially the same ‘piece of energy’ that is currently over the western Pacific near and east of Japan. It should be noted the European Ensemble (not shown) is much more aggressive with the jet and troughing.


 

The biggest question in my mind now is how effective these troughs (storm systems) can eject east into the Great Plains. The concern is the projection of lingering tropical convection west of the dateline in late April/early May could promote ridging across the Rockies/Plains (some computer models suggest this trend). This would keep much of the troughing over the western states and could limit the severe potential across the Great Plains. But at the very least I think individual shortwaves will eject into the plains and bring a severe pattern equal to what climatology would suggest for this time of year. After all, there’s no sense in being picky here. The pattern has been very quiet and any uptick in activity is a welcome change for storm chasers!

But as can be seen in the images above, the Pacific jet stream is poised to extend into the eastern Pacific by the end of the month. As seen by computer models (one example shown above), this jet extension should bring a deep trough into the western states, which should then either eject east or send a series of shortwaves into the Great Plains. As I already said, the MJO is weakening, so just how deep of a trough we can get to eject into the plains is in question.

Though it seems clear the severe storm/chasing activity will come to life during the final week of April, perhaps extending into early May. If we can get another jet extension following this one, then maybe the increased severe activity will extend into the first ten days of May. We’ll just have to remain hopeful and keep our fingers crossed!!

 

Until next time…

 

Jim