Monday, November 7, 2011

Now: storms

Well, it appears I was a touch too far south with my forecast. But here's a screen capture of the RADAR as the storms happen right now. Wow.

Sunday, November 6, 2011

November severe weather setup

Down south storms can happen almost any month out of the year.

Including November.

Tomorrow looks to be a really good setup for severe weather in north-central Texas. So let's go through the checklist in our ingredients-based forecast.

Surface dews look to be over 60 in the region and even over 65. Easily plentiful for this time of year. And to boot, it's not a wishcast of the model--the dews over 60 are already in place. 850 moisture looks good, too.

MLCAPE is progged to be in excess of 1500 J/kg. Lots. No CIN.

The model indicates good convergence along the fronts, but in the warm sector not much is shown. This could be a limiting factor. However, we can infer strong synoptic-scale lift from the cooling and strong winds at 500 mb.

Tons, both at low levels and at high. Winds at 850 mb should be in the 30 to 40 knot range, and at 500 mb, around 50 to 60 knots. Veering looks to be pretty good, so the deep shear values will easily support supercells and low-level shear will support low-level rotation.

So what do I think will happen?

Notice the time in all the maps above: 18Z. Included in that is the cap strength, which is nil by 18Z. That's noon, CST. However, with subtle warming going on at 700 mb, storms may be slightly capped. On the other hand, strong winds and cooling at 500 mb indicate likely strong lift. Therefore, I expect there to be storms ongoing late in the morning and, as long as the warm sector remains at least partly sunny, they should intensify through the afternoon. Looking at the forecast soundings below, the low-level jet is forecast to intensify through the afternoon, lengthening hodographs and increasing low-level shear. So the ongoing storms will become more and more likely to rotate at low levels. Provided one storm can stay discrete, tornadoes look to be likely, along with big hail and strong winds.

My target area is between Seymour, TX and Wichita Falls, TX. Prime time will be about 3 PM. Sunset is about 5:30 PM this time of year, so the viewing time will be much shorter than at other times of year. Storm motion won't even be too crazy--20 to 25 knots.

If I were out in that part of the world, I would definitely try to catch a November tornado.


Storm motion:

18Z prog sounding:

21Z prog sounding and hodograph:

Thursday, July 7, 2011

Back to regular life and setups

So wouldn't you know it, there's a setup on the way that looks really good. I'm talking spectacular. Let's talk about it.

Moisture is at its peak right now. Surface dews are progged to be in the low 20s. Up to 850, even, it looks to be moist--dews over 15°C.

That will lead to slightly-capped MLCAPEs in excess of 1000 and even 1500 J/kg. Not too shabby, if you ask me.

With 500 mb flow increasing with the approach of a vigorous trough, deep-layer shear will be good--great, if you add in the 850 mb winds crossing rather nicely (shown above).

Surface lifting will, I suppose, be a question but if a front or outflow boundary sharpens up, the game will be on.

If I were chasing, I would aim for Weyburn, SK, for an initial target and go from there.

Wednesday, June 22, 2011

U of M chase trip is leaving tomorrow

We're off tomorrow morning, pretty early.

I will be posting the bulk of my updates on the other blog-- check it out if you like.

I'm excited, like a kid on Christmas Eve. Or me on Christmas Eve, truth be told.

Tuesday, June 21, 2011

U of M trip forecast: better late than never

So here’s what it’s looking like now. I will post my ideal locations as though we had a teleportation machine. Since Thursday is the theoretical earliest we can start chasing, I will start from then and go as far into the future as Canada Day. I will give each day and run a completely arbitrary rating on a scale of 0 to 10, 0 being horrible and 10 being the best setup ever. Keep in mind this is model land and I’m basing my judgments on believing as though the depicted scenario were exactly what was going to happen.

NAM (12Z):
Thursday – northern Montana and/or adjacent areas of AB/SK (4 – instability is kind of weak and winds are a little far back)
Friday – northeast Colorado/Nebraska panhandle (6 – instability and deep shear are good but the directional turning is only okay)

GFS (12Z):
Thursday – central Alberta (5 – instability is weak but the winds are more favourable)
Friday – northwest Nebraska/southwest South Dakota (6 – instability and deep shear are pretty good but the directional turning is lacking)
Saturday – northeast Colorado/Nebraska panhandle (6 – instability and deep shear are pretty good but the directional turning is lacking; do we sense a theme here?)
Sunday – a few areas, including western Kansas (5 for okay deep and directional shear with good instability), the Nebraska panhandle (7 with good potential juxtaposition of parameters but it may be only okay) or northern South Dakota (6 with slightly weaker winds)
Monday – southeast Alberta (6, as wind fields are better but moisture is lacking) or northern South Dakota (6 for good instability but weaker deep wind shear, although nice turning)
Tuesday – western North Dakota (8, as wind fields, both deep and directional, and instability look better)
Wednesday – western Manitoba or southwest South Dakota (9 – instability and shear look really good)
Thursday – northwest South Dakota (4 mainly for capping)
Friday – western North Dakota (8 if the cap breaks)

ECMWF (00Z) (I can’t do forecast soundings, though, so I have to guess the ratings a bit more):
Thursday – eastern Alberta (6 depending on moisture)
Friday – eastern Montana, I think (5, based on it’s unclear but looks like there’s some potential)
Saturday – southern Saskatchewan (6)
Sunday – eastern Dakotas (7)
Monday – western Kansas but probably too capped (4)

GEM-Global (12Z and 00Z):
Thursday – northern Montana or southeast Alberta (5)
Friday – southeast Saskatchewan (6) or western Kansas if it’s not capped (6)
Saturday – central South Dakota (7)
Sunday – north-central Nebraska, specifically Cherry freaking county (7)
**now changing to 00Z run**
Monday – maybe the Colorado front range, but that looks marginal (2)
Tuesday – eastern Alberta (6)
Wednesday – eastern Dakotas or the Red River Valley (7)
Thursday – southeast Alberta (8)

NAEFS (00Z):
Thursday – southeast Alberta (5)
Friday – Nebraska panhandle (6)
Saturday – western Nebraska (6)
Sunday – western North Dakota (7)
Monday – western North Dakota (6)

Wow, that was exhausting. The models are seeming to key in on a potential play on Thursday in Alberta, but then they almost all unanimously drop the potential into the states, and well into them at that. Nebraska panhandle for a couple of days, or maybe into the Dakotas. It seems that the usual suspects, moisture and midlevel winds, are the main players here. Moisture is there south but the winds aren’t. And it seems the good midlevel flow dies as soon as it hits North America. Weird.

(cross-posted at the Weather Central blog)

Monday, June 20, 2011

CoD trip pictures

Here some of them are. In these pics you'll see structure, a tornado, and some lightning shots. Enjoy!

Sunday, June 19, 2011

CoD chase, day 9 recap

We started off the morning in Garden City, KS, full of hope. We went east for some yummy BBQ in Wichita. Then we dropped south, as satellite and RADAR indicated convergence near the Oklahoma border. We went hither and yon for a while, waiting for initiation, as the cumuli were becoming rather congested and MLCAPEs to our immediate southeast, the airmass source region, were approaching 5000 J/kg. Sweet.

Storms finally fired up and we were on the south one in a jiffy, and as soon as we got to the south of it, it showed us a beautiful structure, with striations and nice midlevel rotation. We followed it for a few hours, and a couple of times we witnessed clear slot occlusions; still no tornado.

The road options were getting a little sketchy, so we had to drop southeast by about 15 miles. And wouldn’t you know it, when we’re coming back north, that’s when the storm decides to tornado. We saw it and dropped a report on Spotter Network. We couldn’t find an appropriate place to pull over for pictures for a while, so we had to settle for van pictures.

Not bad, though, as the tornado was on the ground for an estimated 15 minutes. After the old circulation got gobbled up, the new circulation tried hard but could never regain its strength again. So we went to grab food and unload water, and set out north for some lightning pictures. Some pictures acquired were amazing. After about a half hour of that, we left for the hotel in Springfield, MO.

Pictures will on their way tomorrow.

Saturday, June 18, 2011

CoD chase, day 8 recap and day 9 forecast

We started the morning knowing things would get going early in Colorado. It's a lot like Alberta in that the storms form because of the mountain-plains circulation. If there's cold air aloft and some flow, storms go early and they can go big. We were dealing with low dewpoints, however, and so we were expecting wind and hail makers.

And that's just what we got. We got a bunch of really neat structure while staying on storms for hours and hours. We were in cold air and warm, moist-ish air and dry. I took more pictures yesterday than I have in all my other chase days this year combined. On the way back to the hotel we took some lightning pictures, although most were marginal. The lightning we watched later in the van was amazing, mostly sheet, and constant. Coupled with blasting music by Rush, and it was a great day.

Today we're looking to southeast Kansas. Moisture--surface dewpoints are already in the low 70s F. Instability will be there because of the moisture, and we're looking at MLCAPEs of 3500+ J/kg. Uncapped. Lift should be good along a composite warm front/outflow boundary, enough to overcome the only modest cap characterized by 700 mb temperatures of 10C. Shear will be good. 35 knots at 500 mb from the west and easterly surface winds of 10 to 15 knots will make storms easily rotate. We'll even be in the left exit region of an 80 knot 250 mb jet.

Now the minuses will be the moisture at 850 and winds at 700. The surface moisture will be good, so that should overcome the lack higher up. As for the 700 winds, I don't know what to say or what effect it will have on storms--strictly speaking, though, the hodographs won't be too bad, especially in southeast Kansas.

I expect we'll be looking at wet classic supercells today, given the moisture. Who knows what kind of surprises we may see. It should be fun. (Especially after stopping at Hog Wild). (Maybe.)

Friday, June 17, 2011

CoD chase, day 7 recap and day 8 forecast

Yesterday was a neat day. We were expecting some supercells with a chance of tornadoes, but something just didn't go. Likely the moisture was to blame, but this year it seems to be either too much or not enough, or too much forcing or not enough--that delicate balance doesn't seem to want to show up.

Still, though, we caught some great shelf cloud structure. Pictures may or may not happen soon, depending on when we end up leaving on our trip. Speaking of which,I normally do extended forecasts for the trip based on the models and show how wildly they vary from day to day, but I have no time right now.

Today we're going to play the Palmer Divide east of Denver. Maybe, maybe not; this place is famous for its landspout tornadoes, and you never know.

Thursday, June 16, 2011

CoD chase, day 6 recap and day 7 forecast

Yesterday we just drove from Council Bluffs, IA to Kearney, NE (pronounced "carny"). We stopped at the pioneer museum they have in the archway over the highway. It was really geeky and awesome; I learned a lot.

We sat in a restaurant/bar and watched game 7 of the Stanley Cup finals. I was--am--crushed about the results. And what bothers me is that some the so-called Canucks' fans rioted. Not cool, people, not cool.

Onto today. We're optimistic about things going in the Nebraska Panhandle area, with not bad flow out of the southwest aloft juxtaposed with upslope surface flow. We had been considering the central Kansas play, but a morning MCS blasted through and pooped out an outflow boundary that currently sits in southern Kansas and is unlikely to rebound into an uncapped region by this evening.

Tomorrow looks like an only okay day, so we might end up in Colorado or west Kansas to see some storms. Saturday, however, could be a sweet day in southwest Kansas.

Carry On, Wayward Son.

Wednesday, June 15, 2011

CoD chase, day 4 and 5 recap

On day 4 we were right for the most part. It ended up being super capped over southeast Nebraska. A lot of people busted and Hobson owes me a coke.

The storms we did get, though, were frustrating. It seems like every time we got to a storm it dies. For instance, we were sitting in Kimball, NE, watching storms come out of Wyoming. They were in really dry air, sort of out of our target area. So we abandoned those to go to storms farther south Colorado. One started to look good and according to RADAR acquired rotation. But as soon as we got to within about 10 miles of it, PAAAH.

So we gassed up and went back north, where storms were initiating. They were initiating as lines and clusters, so we kept going. Going where? To the erstwhile Kimball storm that now looked like a pretty mean beast on RADAR.

Naturally, until we got close to it. It died right in front of our eyes (well, it was getting dark so really it died in front of our RADAR) and we went to Sidney for the night.

The next day was an early and long one--hence the not blogging. (Sorry.)

The new NAM and RUC were forecasting a major outbreak in north-central Missouri and south-central Iowa. It was a setup we had to chase.

What happened? You guessed it. We drove all day to get from western Nebraska to northwest Missouri. Storms started firing up and we went to them, only to kill them. One storm in particular was looking really good on RADAR--right location, shaping up nicely. Then we lost data and the mount for the laptop screen broke, Paul's radio wasn't working properly, and naturally the storm died. We got right underneath it and the updraft was a little orphan anvil. What happened? Cap, perhaps.

It was kind of frustrating, because of the build up for a rather humdrum denouement. That and we forecast the right area and it *still* went bust. I suppose the schadenfreude part of me is content knowing that many people busted in the area yesterday.

It is a down day today. We're going to Kearney, NE, for repositioning today from Council Bluffs, IA. We'll go see some sights and this evening is game 7 of the Stanley Cup Finals (GO CANUCKS GO!!!). We're looking at around Kearney for the chase tomorrow anyhow, so the reposition will be a good one.

Monday, June 13, 2011

CoD chase, day 4

A brief rundown of day 3: cap bust. We stayed the night in North Platte, NE.

So today we've got 2 plays to think about: one in the foothills of Colorado and Wyoming, and one in southeast Nebraska.

The play in Colorado is very unlikely to be a cap bust, but the directional turning of the wind doesn't look as impressive. All the other parameters for supercells will be in place, provided the stratus and drizzle to which I woke up clears away.

The southeast Nebraska play is more conditional but potentially has great storms, with great directional turning. Thing is, it really is a potential cap bust and the chase territory turns pretty bad pretty quickly.

So, do we go to a pretty much sure thing that may or may not produce a tornado, or do we go to a maybe that, if it goes, produces grinders (high risk, high reward)?

Stay tuned to see what happens next time on As The Meteorologist Chases.

Sunday, June 12, 2011

CoD chase, day 3

Yesterday we caught a pretty cool HP supercell in the Oklahoma panhandle after much rumination on the fact that the moisture wasn't all that great. The best storm, though, appeared just to our south, unchaseable because of positioning, right on the nose of the theta-e axis. D'oh!

Now onto today.

I was really hoping Thompson would have this crystal clear depiction of what was going to happen today. But no! Complicated forecast! Unfortunately I agree. I have been looking at about 4 different areas. Logistics say no to SD so let's see what else is there.

OFB pushing into OK. It seems to me that they are in the heart of the cap. VERY conditional and I do not believe the cap will break south.

Eastern KS. The earlier HRRR was breaking out nice convection out east but I do not like that any more and neither do the models. Well, most of them. The NAM still hints at stuff there. I am not a fan of that section of the ridge for initiation. Plus the remnants of the overnight MCS a making that less and less interesting.

NE CO. I like this area. The low-level upslope does hint at a good flow of moisture to the higher terrain. The 850 analysis has strong flow over wrn KS and there is a definite wave coming northeast. I actually think that storms could go farther south but at the same time, that is in the heart of the cap.

North central KS looks good too, at least in the RUC's mind with erosion of the cap. I am concerned about the exact forcing mechanism but like the wind structure of the atmosphere there and think that storms could go and go big. It is also on the northern end of the cap and the cap may be breakable. We are headed to Hays and will assess along the way determining whether to go east a bit or head back west.

Saturday, June 11, 2011

CoD trip, day 2

Well, actually I'll start with a quick recap of day 1.

We drove through St. Louis and stopped at Pappy's, where I had some of the best ribs I've ever had--tender, juicy, smoky, mmmmm!

Farther west, across central Missouri, storms were firing up and happened to be on the way to crossing our path. So we went for one of them. It produced hail to the size of loonies, so we made that report to the NWS. We went west to keep on our repositioning.

It was actually a nice little bonus for a day on which we had expected not much--we got a little more. There was a shelf cloud with which we could do a little teaching, but otherwise it was pretty meh.

We stopped for dinner at a steakhouse in Kansas City, some of us listened to the Canucks go up 3-2 in the Stanley Cup finals, and we stayed the night in Junction City, KS.

Today is a bit of a dilemma, but I think we can avoid the problem by heading toward kind of the middle of the dilemma areas and decide on one on the road. The locations seem to be either southeast Colorado or far western Oklahoma--they're not too far apart from each other, so that's a little bit of a good thing.

The moisture is better in Oklahoma but it will be hotter; the moisture will be okay in Colorado but the temperature will be lower. So cloud bases should be at more or less equal relative heights. Instability is not a problem, with MLCAPEs near 2000 J/kg. Lift is interesting, as there might end up being a dryline/warm front intersection in Oklahoma, whereas the Colorado lift would be due to upslope flow. And wind shear--maybe that's the kicker. So to speak. We're looking at water vapour loops and upper charts, and as of this writing a couple of soundings, crucial (to us) ones, are missing. Great.

So we'll see. Follow us along on one of the links.

Friday, June 10, 2011

CoD trip, day 1

So it's been a while since I wrote here, but it's time for my second trip of the year. I am now chasing with the College of DuPage.

Today is a repositioning day. We started out from the college at about 9, and we're going in the direction of Kansas City. Today's setup is one we'll sort of see but it's not getting us too excited--the shear is displaced to the north of the instability. The juxtaposition may get close today, but it's marginal at best.

Tomorrow's setup is what we're really looking at. The front that's right now sitting across central Missouri and southern Kansas is forecast to stall and maybe return north a little bit. Moisture shouldn't be a problem with dews in the upper teens to low twenties. The flow looks to be a little weaker than it was a couple of weeks ago so perhaps the enormous forcing won't be there and the storms will be more isolated.

The problem is this: we're looking at two distinct and rather separate areas: southwest Kansas and northeast Colorado. The Kansas play looks to be a dryline/warm front intersection, and the Colorado play is a classic upslope situation. The MLCAPEs progged are the same and upper flow is similar, too. At least according to the last model runs we looked at.

So tonight we're likely staying somewhere around Junction City, KS, so that we can decide in the morning which play to go for. And it's a case of once we commit, it's pretty much our play for the day.

To follow along, there are three (well, two and a half) ways, aside from this blog. First off, follow our icon along on GRLevelX (if you have it); Paul Sirvatka is the name. Second, follow on this page that has our location on a Google map:
This is the link.

Third, follow along on two Twitter accounts, where Paul will tweet from next to me, and the CoD lab will tweet back. Sometimes the banter is about weather, sometimes not so much. Here are the links:


Sunday, May 29, 2011

Forecast for May 30

Memorial Day. It's last year on this day that we caught a beauty.

This year looks like an okay setup for supercells, although tornadoes may be a little more elusive than last year.

Here's the rundown.

Moisture: copious. Not a concern, with surface dews around 20C likely to pool and moisture plentiful and deep.

Instability: plentiful. MLCAPEs are likely to be above 2000 J/kg all over the place.

Lift: should be good, with a surface low and fronts galore.

Shear: I have left this one to last, as it's the most telling. The shear is mostly linear, leading to a) linear (i.e. non-discrete) storms, and b) fast-moving storms. This could be a problem.

All that being said, if I could chase, I would begin by targeting Fargo, ND (assuming the NAM is right and actually, the GEM-REG is quite a bit farther north with this system) and going from there.

Wednesday, May 25, 2011

Day 7: bonus day

We hadn't really counted on chasing today, but it looks really good just to our east. We're currently north of Kansas City, which has a tornado warning out. Doppler looks good.

Anyhow, we're going to target the area of north-central Missouri (I know, not great territory) to western Illinois. Things are lining up there, and it's just a matter of whether or not we'll get lucky.

Day 6 recap

In a word, ugh.

We set out of OKC in the morning and targeted El Reno and points west.

We had lunch in El Reno and watched the dryline bubble up and start deep moist convection. Because of the shear involved, we figured any storm that went up big would be a long-lasting, prolific tornado producer.

Wow, were we wrong.

Just as we lost data coverage (thank you very much, western Oklahoma), the storm fell apart. Problem is, we couldn't see that because of the haze. So we were following along based on tornado warnings relayed by local radio stations.

When we finally got data coverage back, it was obvious we were behind a barely-broken line of potentially tornadic supercells and in no position to catch them.

What hurt, though, was not only that there were damaging (deadly, actually) tornadoes, but also the fact that just about every other chaser, it seems, caught at least one photogenic tornado. Including the storm of the day, which hit El Reno, where we had had lunch.


Monday, May 23, 2011

Day 6 forecast: outbreak?

If there's no other day you can watch, watch tomorrow.

I forecast that Tuesday, May 24, 2011 will be a big day for severe weather and likely tornadoes in Kansas and Oklahoma.

This time I will go with the full run-up.

Moisture - surface dewpoints in the low 70s F (20C+), and 850 dewpoints 15C and higher.

Instability - SBCAPEs and MLCAPEs over 3000 J/kg.

Shear - 0-6 km shear should be 50 knots or higher.

Trigger - Dryline. Weak cap. Need I say more?

We will be targeting Wichita first, then likely refine to points west for initiation, then move east with the storms. As the afternoon and evening wear on, the low-level jet will really get going, making for tremendous low-level shear.

Cons that I can think of include a slight lack of wind at 250 mb, which might not allow for updraft evacuation as efficient as I would like; this would lead to more HP supercells rather than classic.


I must be missing something, but I can't think of it right now. Here are a couple of forecast soundings for the area.

We will have to be careful tomorrow, as storms will be more dangerous than just about anything I've ever been on. Follow along if you can.