Summary of the day: June 26, 2017

We started the morning in Kearney, NE, with our initial target of McCook, NE.  We had decided on a target area of eastern Colorado, northwest Kansas and southwest Nebraska.

Along the way, we noticed morning ACC (altocumulus castellanus), which is a good indicator of midlevel instability.  Also, when we were on the drive, we noticed (via RADAR and visually) some thunderstorms going to our north and northeast.

We decided to stop and have a look at the storms that were going on, as there was no other action going on in the region of interest.  It was clear that those storms were elevated, as the mushy appearance in real life and disorganized reflectivity on RADAR showed.

Storms still kept going and started to intensify generally to our north, all the while building westward along the slowly-advancing cold front.

At this point, 2 of the 3 vans lost their internet connections.  It made a chase day all the more difficult and stressful, but we managed.

One storm then began to dominate, one that was a little behind the initial broken line but still ahead of or along the cold front.  We decided to stay put and see what it would have to offer.

As we refined our location relative to it, we started to see some structure--a wall cloud, mostly.  Some good ventilation aloft was evident, as well.

The storm then quickly really became rather mean.  It showed us alternating low-level outflow and inflow structures, so we were in inflow at one moment and in outflow at another; the outflow was rather chilly and wet, but the southeasterly winds into the storm complex told us that the storm wasn't done.

We were stopping and taking pictures, then driving a little west as it surged more outflow south and a little west.  Eventually we came to a town where we could cross the Platte River and chase not just west but south.  This was a great option for us, as the southward reach of the storm was latitudinally equal to our location.  We got south and then got west just ahead of the outflow, hoping to see something good.  And see something good we did: we stopped just short of the best gustnado I've ever seen.  It was a long-lived compact vortex of wonder, awesomeness and dust.  It last for about a minute, maybe a bit more. Justin's video even got picked up by The Weather Channel.

After the gustnado, we were a little jazzed up but ready for more.  We got going west some more and We turned onto another road, a rained-on dirt road.  Not the best idea, as we immediately started sliding as though we were on ice.  Oy.  Justin stopped and we advised the other vans *not* to advance on this road.  Justin then put it in reverse and (rather heroically) inched backwards approximately 100 metres back to gravel.  There were a few times we were close to sliding off the road, but Justin kept that from happening.  (Thanks, Justin.)

The storm we had been watching (we in Chase 1 called him Gus) started to decay a bit--his outflow pushed way ahead of his inflow, and the updraft shrank considerably.  A beautiful hail shat was its last gift to us as we decided to move west to catch another storm.

This storm was another one westward along the line, but it decided to get outflowy too.

We went westward to an interesting-looking storm that was dropping south, one that was tucked well northwest of our location.  As soon as we saw it, though, we knew it was pretty special.
Boy, were we right.

We got a little closer to the storm and decided to take a dive south so we could see it better; a navigation error meant that we missed our turn-off and had to turn around.  Well, at the turn around near some grain silos, we stopped and got out to take some pictures.

This is where the storm decided to show us some great stuff.  The lazy low-level rotation tightened up really quickly.  It was strongly ingesting air, with help from some modified outflow from the storm to our southeast--it was raining into our updraft region.  I think that this storm was actually helped and hindered, simultaneously, by this rain.  It cooled (stabilized) the inflow region and moistened (destabilized) it, making sure the updraft base was lower.  It was ingesting surface-based parcels or near surface-based parcels, and the base looked to be below 1000 feet AGL.  then, the rotation got focused in one region and (I'm not kidding) we were all chanting "GO GO GO" at the storm; this was as close to producing a tornado as I've ever seen a storm be without actually producing.

After a while the low-level rotation weakened substantially but the broad-scale rotation was still good and so we decided to drop south with the storm, knowing that this was the storm to be on.

As we went south, it continued to show us HP and classic looks, with scary hail cores evident and then good updraft areas prominent.

We kept playing with the storm, as it was showing large to very large hail, so we stayed out of its core (for the most part).  We stayed back for a bit and tucked in behind the storm to see how big the hail was along the side of the road, and we got hail that was, at its largest, quarter-sized.  We notified the appropriate NWS office and went on our way.  Moving southward through the hailfall we encountered another neat phenomenon: hail fog.  It was pretty neat and eerie to see.

Finally running ahead of it, the storm decided to give us its last look.  It quickly morphed from a scary HP to a stunning LP supercell and it was so quick that I couldn't quite believe what I was seeing.  All of a sudden we were seeing striations and a huge separation of the updraft from the precipitation core.  At the same time RADAR was showing a marked increase in the hail size, despite it looking rather transparent visually.

A sheriff stopped to talk to us for a while.  He was extremely friendly and seemed to want to share his stories.

Eventually the LP structure started to decay, and it was time for us to get some fuel, both for our vehicles and for ourselves.  We stopped at a gas station where the storm gave us its last hurrah; it was severe-warned as it moved over us in Scott City, although the hail we eventually got at the gas station was about pea-sized, no more.  A little wind made the rain rather horizontal, and then that was the end of it.

Dinner was at a down-home place called Tate's; wonderful large portions of good food and friendly service.  I would recommend that any day of the week.

We had our overnight in McCook, NE, in eager anticipation of the next day.

Bonus forecast for the trip, posted July 24

Here's an extra forecast for the trip that I did up this morning.

I’ll say that the week looks interesting, and we should be able to catch some really good storms.

 

It’s interesting that there’s a bit of model spread on the evolution at the beginning of the week and the end, but not so much in the middle.  In other words, Monday and Friday are the big question marks.

Some models have less moisture returning into Kansas on Monday and some have more, so the character of the storms will be affected greatly.  If the moisture is slower to return, then perhaps southern KS is more in play or even into CO.  So that makes it an even better idea to make it to Kearney tomorrow.

Tuesday, Wednesday and Thursday are all good to great days, depending on the model you choose, and the locations vary but the most highly variable day is Tuesday, which could be good anywhere from Nebraska to Manitoba.  A broad moderate westerly upper flow will overspread the entire region, so it’ll be a bit of a needle-in-a-haystack thing, and I think playing the edge of the cap will be best.

Wednesday should be central to east KS or NE, with a warm front and perhaps dryline bulge play.  On that, the models are in good agreement.

Thursday, same thing, except maybe more instability and a stronger dryline.

Friday is where it gets highly questionable.  The 06Z GFS smashes a cold front waaay south now, to the point that nothing would be a good play.  The 00Z and 12Z runs of the GFS don’t do that but take that day’s play a little east, potentially into the jungles of central MO and potentially into the flats of IA.  The ECMWF portrays another warm front play in the central plains, with tons of instability and pretty good flow over KS.  The GDPS actually agrees with the ECMWF, too.  So we will see; to say it’s highly in question is a fair statement.

 

This looks like it will be a good trip.  Pack lots of shorts, because aside from an occasional cold outflow, most of the time we should be in the 80s and 90s F during the day and, at night, 60s early on and upper 60s to 70s later on.

I have had good luck this year in finding good places to eat, so aside from helping with the other stuff, I’ll endeavour to find us some yummy food.  My search for good burnt ends is in full force, too, so I may steer us to BBQ places that serve them, but I will try to include some variety as well.  Chasing will still be #1 and, if the only place we can get food once done chasing and lightning photography (I suspect this year will be perfect for it, BTW—warm evenings and storms going well into the nightttime hours) is Pizza Hut or Applebee’s, well, that’s fine too.  It’s storm chasing first, not eating.  That’s just a sideshow. :)

 

I plan on being at the vans around 7:15.  I have my 2 ham radios set up, charged and ready to go.

My laptop is good and ready to go—it’s an old workhorse, about 2011 vintage, but all the software is installed and updated.

I'm getting stoked for the trip.

July 20 forecast

Day 1 (June 23): almost guaranteed to be a ravel day if we chase

NAM: TX panhandle/eastern NM

GFS: northeast NM/TX panhandle

GEFS: eastern CO/eastern NM/TX panhandle

GDPS: southeast CO

ECMWF: eastern CO/northeast NM

CFSv2: northern TX panhandle/northeast NM

Day 2 (June 24):

GFS: north-central NM

GEFS: northeast NM

GDPS: eastern CO/western KS

ECMWF: northeast N

CFSv2: northern TX panhandle/northeast NM

Day 3 (June 25):

GFS: southeast CO/northeast NM

GEFS: southeast CO/eastern NM

GDPS: southeast CO/southwest KS

ECMWF: south-central CO/north-central NM

CFSv2: eastern NM/west TX

Day 4 (June 26):

GFS: southeast CO or central AB

GEFS: eastern NM to western KS

GDPS: eastern CO/northeast NM

ECMWF: eastern CO or east-central AB

CFSv2: eastern NM or central AB to central MT

Day 5 (June 27):

GFS: central NE or central AB

GEFS: eastern NE

GDPS: eastern CO/western KS

ECMWF: western KS, southern MB or central AB

CFSv2: eastern NM, the Dakotas or southern MT

Day 6 (June 28):

GFS: eastern SD/NE to western MN/IA

GEFS: eastern NE/western IA

GDPS: central KS to central NE

ECMWF: northern KS to eastern ND

CFSv2: southwest KS to northern TX panhandle or eastern W/western SD

Day 7 (June 29):

GFS: eastern ND to eastern KS

GEFS: NE/IA border

GDPS: eastern ND/western MN to central OK

ECMWF: western NE or most of IA and IL

CFSv2: northwest NE/southwest SD

Day 8 (June 30):

GFS: western IA

GEFS: NE

GDPS: central IA

CFSv2: northwest NE/southwest SD

Day 9 (July 1):

GFS: most of NE

GEFS: northeasy KS

CFSv2: most of SD

Day 10 (July 2):

GFS: eastern MT to northeast CO to southern IA

GEFS: northeast NE to southwest MN

CFSv2: most of ND, southern SK, southern MB

It now seems model solutions are coming more into agreement, at least for the beginning of the forecast period.  As usual, this makes the departure date more complicated.  A few factors are coming into play.

1. Models are in fair agreement that a pretty good setup is likely on June 24 and 25 in eastern CO and vicinity
2. Models are in okay agreement that better setups will occur starting on June 26
3. Models are showing some serious instability toward the end of the trip if we had a late departure
4. Models get worse and worse the farther into the future you go

So do we go and get good storms and maybe really good storms, all while having to return when there's the conditional chance of some *great* storms, or do we leave a couple of days later, catch what will likely be really good storms and then unknown after (but models are saying it'll be really good)?

June 19 chase forecast

This evening I had a bit of a peek at the model output before writing this, and it's still amazing to me, after all these years, how much things change from run to run.  The imminent tropical depression/tropical storm is such a big pattern changer that even small deviations in its track will make for big chase changes.

Day 1 (June 23):
GFS: eastern NM to central OK
GEFS: southeast CO/eastern NM
GDPS: AL to middle TN
ECMWF: northeast CO
CFSv2: northeast NM to central OK

Day 2 (June 24):
GFS: southeast NM
GEFS: southeast NM/southern TX panhandle
GDPS: the Carolinas?
ECMWF: central KS
CFSv2: eastern NM

Day 3 (June 25):
GFS: eastern NM
GEFS: southeast CO/northeast NM
GDPS: maaaaaybe western KS
ECMWF: Kentucky and middle Tennessee?
CFSv2: central AB

Day 4 (June 26):
GFS: eastern CO
GEFS: eastern NM to western KS
GDPS: southwest MB
ECMWF: AB elbow
CFSv2: south-central AB, SK/MB border to central SD

Day 5 (June 27):
GFS: eastern SD/eastern NE
GEFS: northeast NE
GDPS: central MN
ECMWF: central AB
CFSv2: southeast SD

Day 6 (June 28):
GFS: northeast CO to western WY
GEFS: southeast SD
GDPS: southern NE
ECMWF: central AB-central MT
CFSv2: eastern WY/western NE

Day 7 (June 29):
GFS: eastern WY/southeast NE
GEFS: southern MN
GDPS: southwest SD
CFSv2: southwest SD

Day 8 (June 30):
GFS: eastern KS/western MO
GEFS: southeast SD
CFSv2: northern TX panhandle

Day 9 (July 1):
GFS: eastern NE/southwest IA
GEFS: eastern NE/most of IA
CFSv2: southeast NM/southern TX panhandle

Day 10 (July 2):
GFS: central SD, NE/IA border, central IL
GEFS: IA/southern MN
CFSv2: southwest SD

So I'm a little skeptical about the moisture returning to Alberta the way some model runs depict it. There are 2 potential sources of moisture--advection and evapotranspiration.  Evapotranspiration is only maaaaaaybe just starting up at this point, so I don't think we can count on a big boost from it.  As for advection, models depict moisture being shunted southward to, alternatively, New Mexico, Texas or even the Gulf of Mexico.  Then it magically appears in Alberta?  I don't know that that's a reasonable thing to happen in such a short time.  So at this point it looks to me like farther south plays will be likely, in the higher(ish) terrain of Montana, Wyoming, and Colorado; perhaps New Mexico is in the cards, too.  Later in the period the Gulf is forecast to open up and give a good stream of moisture to the southern and central plains.  This would mean better tornado chances, if better flow can get juxtaposed overtop.

Although a lot is inconsistent, I am encouraged by the consistency of the forecast of a) a mid-level trough acting on that airmass sometime in the June 26 to 30 range, and b) deep moisture return.

Details have yet to be ironed out but, as Pat said in a message earlier today, I'd maybe plan for (but not be 100% set on) a later departure.  The direction will be either west or south, and my money is on south.

Also of note, we have been doing these trips on and off since 2005.  I don't want to toot our own horns, but I will reluctantly do so: in all the years we've chased with this group, I can't remember more than 1 or 2 times when we've missed a forecast, and those times it was a forecast of marginal storms; the big stuff, we've nailed.  Our history shows that we almost always get to the best storm that is feasibly reachable for us.  I hope and plan to keep this streak going.

Long-range forecast, issued June 18, 2017

It's approaching midnight CDT, I have some free time so I'll do this again.

I can tell you that model runs, since yesterday's iteration fo this forecast, for the first few (potential) days of the trip showed craptacular chasing, with a reloading of the moisture and flow taking place.  If this should prove to be true, we would likely not leave on June 23, unless positioning required it.

Now, let's see what new guidance is suggesting for us.  As I'm typing this, I'm seeing the guidance I'm basing it on for the first time.  Just FYI.

Day 1 (June 23):
GFS: eastern NM
GEFS: eastern KS
GDPS: eastern CO
ECMWF: eastern CO/western KS
CFSv2: western KS

Day 2 (June 24):
GFS: central TX, central NM
GEFS: eastern OK/northwest AR
GDPS: western KS
ECMWF: southern OK
CFSv2: central NM

Day 3 (June 25):
GFS: central AB
GEFS: northeast NM
GDPS: southeast KS
ECMWF: maaaaaaaybe the southern TX panhandle
CFSv2: central AB

Day 4 (June 26):
GFS:  SK/MB border
GEFS: southwest KS
GDPS: southeast CO/eastern NM
ECMWF: central AB
CFSv2: southeast NM, western NE, central AB

Day 5 (June 27):
GFS: eastern SD, eastern NE
GEFS: eastern NE
GDPS: eastern CO
ECMWF: southeastern AB
CFSv2: eastern MT to western NE

Day 6 (June 28):
GFS: northeast NE to western WI
GEFS: eastern NE/western IA
GDPS: western KS
CFSv2:  western SD to western KS

Day 7 (June 29):
GFS: northern NE
GEFS: eastern NE/most of IA
CFSv2: western KS to northwest SD, northeast ND

Day 8 (June 30):
GFS: southeast SD/northeast NE
GEFS: eastern NE/western IA
CFSv2: central SD to TX panhandle

Day 9 (July 1):
GFS: northeast NE
GEFS: eastern NE to western WI
CFSv2: central OK

Day 10 (July 2):
GFS: northeast KS to southeast MN
GEFS: southern MN/northern IA
CFSv2: northern TX panhandle

So a couple of models take storms pretty far down south then fling the action into Alberta with an impressive upper trough.  If that were to happen we'd probably blow off the southern play.  A couple more like a lot of upslope in New Mexico and Colorado--perfect for really photogenic storms.  Yet more seem to key in on storms settling in for a few days in the central plains.  All of these are interesting scenarios, and the model spread thus makes it pretty much impossible to say which is more likely to happen.

It's funny.  Every year has its quirks.  The first few years, we were doing trips in July, which can be feast or famine, and we mostly had famine (relatively speaking).  Then we switched to earlier and we had some years with flow but no instability, instability with no flow, and then in 2015 we had a couple of good days, and one day in particular, where everything came together.  The models seem to be all over the place right now (as per usual) but the 2 things they're seeming to key in on is that, for at least some of our trip, there is likely to be a favourable juxtaposition of instability and shear.  The problem will be finding those areas and getting there.

Starting tomorrow, model solutions should start to converge on the most likely outcomes.  Decision time is still a few days away, and I honestly have no idea which way it's going to go--Friday departure or later.

Chase 2017 is on the horizon

I haven't posted in about 2 years here.  We do the chase trip every other year, and in between it remains dormant.  I'll endeavour to keep these posts going while a) we're gearing up for the trip and b) on the trip.  I can't make any promises, except that I'll try my best.

In the past, leading up to U of M storm chase trips I've done post after post outlining how the models suck at long-range forecasting, especially as it pertains to deep moist convection.  I will sort of do the same thing here, although it won't focus so much on how much they suck as what solution(s) they're converging on.  The reason is that, the farther into the future you go, the more wildly variable solutions can be.  Previous posts have gone way out to the edge of the models' temporal domains, but this one is going to start out in the realm of higher likelihood.

All that said, there's an extra wildcard thrown into the mix for these forecasts: tropical weather. Some model solutions depict tropical weather in the Gulf of Mexico over the next week or so. Tropical depressions are well known as processes that really mess things up in model land.  What this will mean, then, is that there is lower-than-average confidence in the forecasts outlined below.

Here are the various model solutions from the available guidance as of 11:30 PM CDT June 17, 2017 for the period beginning June 23, 2017.  Also please note that I have 10 days for a forecast, but our trip will only be 7.  What I'm doing down below will help us determine which 7 days we chase.  Not every day is having great storms depicted on every model, so I've put the best-looking location for at least decent storms.

Day 1 (June 23):
GFS: eastern KS
GEFS: eastern KS
GDPS: TX panhandle/southwest KS
ECMWF: eastern KS
CFSv2: southwest NE to eastern NM

Day 2 (June 24):
GFS: OK/TX border
GEFS: northern OK
GDPS: TX panhandle
ECMWF: southeast CO
CFSv2: eastern CO

Day 3 (June 25):
GFS: southern TX *OR* central AB (oy)
GEFS: eastern KS
GDPS: southwest TX/southeast NM
ECMWF: western SD or western NE
CFSv2: eastern CO/northwest KS

Day 4 (June 26):
GFS: TX panhandle to southeast SD
GEFS: western KS
GDPS: southeast CO
ECMWF: eastern KS
CFSv2: most of ND and SD

Day 5 (June 27):
GFS: southeast SD
GEFS: northeast KS
GDPS: southwest KS
CFSv2: southeast IA

Day 6 (June 28):
GFS: western SD/eastern MT
GEFS: northeast KS
CFSv2: western NE/northeast CO

Day 7 (June 29):
GFS: southwest MN/northwest IA
GEFS: northeast KS or Black Hills
CFSv2: southwest KS

Day 8 (June 30):
GFS: northeast NE
GEFS: Western-central IA
CFSv2: northwest KS/southwest NE

Day 9 (July 1):
GFS: eastern NE
GEFS: Western IA
CFSv2: most of NE/western IA

Day 10 (July 2):
GFS: northeast KS, eastern IA, eastern Dakotas, western MN
GEFS: Central SD
CFSv2: eastern NM

At this point, it looks like we will likely be chasing south of the 49th parallel.  This makes sense because, up to this point, deep moisture has yet to consistently make it north to Canada.  This is about the time of year when it really gets advected in, but right now it doesn't appear to be in the cards.  So please please PLEASE, remember your passports.

Aside from saying that we'll most likely be south of 49, it's tough to say exactly where.  There seems to be a somewhat consistent signal that the 23rd will be a KS day--and if we choose to leave that day, there's no way we'd be able to make it there in time.