I don't know what is more thrilling, when you intercept a tornado - or when one of your long-time friends and past tour guest intercepts a tornado.  The latter happened today when I received a text message from Nicole saying there was a wicked storm in the Denver area and she was going to head out an "see what she could see".  Well, what she ended up seeing was a pretty incredible tornado event in the southeastern suburbs of Denver.

She just sent in the above photo taken with her iPhone (Photo taken near E-470 and Smoky Hill Rd), but as any good storm chaser does - she was carrying her Nikon with her and took several great shots from it.  Just as soon as she gets in from her drive back, we'll get her complete chase account and her photos posted here on the blog!

Congratulations Nicole!

UPDATE: Nicole has sent in more photos, along with a narrative of her chase account today.  StormChase.com is posting her account in her own words, which (disclaimer) may not reflect the views and opinions of StormChase.com, it's owner, or team members and/or channel partners 

Before posting Nicole's chase accounts and photos, I wanted to also include this photo of an early morning forecasting session from 2007. Pictured from left to right: Brian Barnes, Marcie, and Nicole Nowlen.

Here is Nicole's chase account:

I must start out by saying I have gone on 2 tours with 2 different groups, learned a lot from both, and have just been teaching myself.  I don't go out much because: 1) I don't have the money. 2) I don't have a partner. 3) My work tends to get in the way. I "armchair chase" more than anything else. With that being said.....

Today was a Moderate risk day and I figured everyone and their brother would be out in NE/KS/IA/MO. I left central Denver around 1:15-1:30pm with big rain drops and actually some small hail. Anyone who lives around here knows storms with wind, rain, lightening and some hail is not uncommon this time of year. I headed towards the south suburbs to home and noticed behind me (to the north) that it was really, really dark. Hopped on C-470 and headed east for the heck of it. Shot a text to Brian about storms. Not long after, radio gave out Tornado Warning for Denver County. All I could think of was "holy crap!!" (When I was 5, my mom and I were not allowed to leave a Target in Littleton because of funnel clouds. We used a pay phone to call my dad who said he was looking out my bedroom window at said funnels. Flashed through my mind today.) They said storm was moving due east at 15-25(ish)mph. Being south of it, I figured what did I have to lose? I could head east on 470. It turns north before crossing I-70 which runs east and west. I had every intention of heading east, then north on 470 to get to I-70 and go east. As 470 turns near Smoky Hill Road, I caught this coming out of sky.

Pulled off the road and noticed many people still passing me. Was concerned that it would cross 470 many miles in front of me, and those people just didn't get it. I still couldn't believe what I was seeing here, not because of the city, but because we are so close to the mountains! Started out as a small, pencil shaped funnel, then got a little bigger. You can make out a slight condensation funnel at the base near ground.

 

I made the mistake of thinking it had passed. Attempted to keep going north (which now I think about it, it was really dumb. I was driving into the core. Wanted to get off 470 and had to get up to next north exit.) Encountered hail that sounded 4" in diameter, but it was more like 2". Pulled off under overpass with many others. Noticed in the sky outside of overpass in front of me that there were small things floating in air. Garbage, paper, limbs etc. Once hail passed, I had to go north to get off 470 still. Pulled over at one point because it was hailing again, but not as big. Was on phone with Brian, when I noticed in my rearview mirror a stove-pipe shaped tornado, and realized it was behind me. (Plus had passed close to that overpass.) Later found out mall took pretty good hit. Got off 470 and took some back roads to get east of Aurora. Took various roads east, then south. I say this because I was navigating off of Google Maps on my iPhone with GPS. I just didn't want in the precip again. Out in Elbert County I caught this funnel at the top of a hill.

 

Few paved back roads later, I pulled over. Air had gotten very cold and blowing south. My first thought was outflow dominant, it's pooping out. Brian helped to confirm this. Snapped this picture of storm, and some very pretty clouds.

 

Ended up helping lady look for her blind bloodhound named Darlin' (not making this up) who I had seen on road. I never saw dog again, but hope she found her. By this time, I was on Hwy 83 between Elizabeth and Kiowa and decided to head home.

On a weird twist of fate, I am moving next week to Parker. I marked it on the map. My new balcony will face east. I would have seen tornado that was in my mirror from this balcony.

All in all, interesting day. Cars a little dirty. Did almost end up in ditch once when I went on to slightly (wet) gravel road. Monitoring one of my tires from said ditch. Might have a slow leak.  

(As I write this, SPC isn't showing many storm reports from tornadoes in the mod chase area. 5 reported tornadoes/funnels came from this one storm today!) All you Mod chasers, eat your heart out!!!

Here is a Google map of locations where photos were shot from: http://www.tinyurl.com/denvertornado 

 

Overnight (June 7th, 2009) a rare atmospheric phenomenon occurred in south-central Oklahoma. No it wasn't a tornado, it was much more rare than that - even during 2009!  Suddenly at about 3am CDT in Jefferson County the air temperature became very hot and dry, the temperature shot up to 97 degrees F, literally within minutes.  The event that happened is called a Convective Heat Burst, it happens when a parcel of very cold and unsaturated air within a dying storm descends very rapidly and warms due to compression (at a rate of 9.8C per 1,000 meters) and overshoots its equilibrium level and reaches the surface.

Take a look at this meteogram from Waurika, OK:

 

Using the above meteogram the hour of day is marked across the top, notice the first image shows a spike in temperature just before 3:00 AM, the temperature rises to about 97 degrees F.  Just as interesting you'll notice the dew point dropped at the same time to about 37 degrees F.   It is obviously not natural even in the heat of the day for such rapid temperature increases - but can you imagine what it must of felt like to anyone that was still awake and outside in Waurika at the time?  

Here is another meteorgram, this one is from Newport, OK located in the neighboring county to the east:

 

Just to make the comparison much easier, I've put the two together and matched up the times:

So was there dying thunderstorms in the area? Yes!  And, I wish I had timestamped these radar images, but you'll just have to trust me that they are from the correct time and date (I'll follow up with a timestamped satellite IR image below the radar).

Notice the storm that forms near Walters and quickly falls apart as it moves to the SE towards Waurika?  This is likely the culprit that created the Convective Heat Burst.

There was a "non-thunderstorm wind gust" report of 58 mph in the area at the time of the temperature spike.  These events don't happen too often, usually just a few times a year.  On August 3rd of 2008 near Soiux Falls, SD a convective heat burst occurred where the temperature went from the low 70s to a record high temperature for the day of 101 degrees F in just a few seconds.  There was also some wind damage that happened with the South Dakota event.  And even though the goal of Vortex2 is to sample supercells and tornadoes, this would have been an excellent event for the team to have sampled due to it's rarity and lack of understanding.

22:02Z 3D radar image from KCYS Cheyenne, WY Radar.  Notice the yellow lines (precip) wrapping around the updraft.  The image below was taken 8 minutes after this radar scan. The tornado was on the ground for over 20 minutes.

Here is another scan, zoomed out and with colors tweaked a bit so we can see the entire structure of the supercell.  Amazing!

Several storm chasers intercepted a tornado in SE Wyoming this afternoon including SevereStudios.com streamer Andy Gabrielson who streamed the tornado live on the Internet!  And, StormTours.com's Adam Lucio!

The tornado was also intercepted by the VORTEX2 team after 4 long weeks of less than optimal weather for storm chasing.  The tornado happened in an open field where there were no structures for it to damage (thankfully) so unless it is rated strictly from radar velocity data, it will have to be rated as an EF-0.

Adam is still in the field chasing and there are new tornado warnings recently issued.  When Adam is done for the day, he'll be sending in his photos and video and we'll post with a meteorological analysis, as well as Adam's chase account.

UPDATE 9pm CDT: "Wedge" report may be bogus.  A few minutes ago someone on the V2 team reported a wedge tornado from Gurley, Nebraska.  Our own Adam Lucio was just north of that location and reported a "Bowl Lowering" but no tornado.  From the V2 team member's position the bowl lowering may have appeared to be on the ground - but it was not.  Adam further reports they were hit with cold air and believe the storm is outflow dominate.

UPDATE 2:25 am CDT: Adam and crew have been traveling all day and just now rolled into their hotel for the night. Due to the extreme lateness and the fact they are chasing tomorrow, the chase report will have to wait.  Just as soon as he gets that info and photos uploaded, we'll post it here.

The purpose of this blog isn't to get into big forecast related discussions, there are already too many blogs out there that attempt to do such things.  That said, I do have the fortunate advantage of explaining severe weather and forecasting information to common everyday people all the time who travel the highways with us at StormTours.com, and I know there are many of you read through this site and you might not understand exactly why we (storm chasers in general) have had such a terrible time in May.  Perhaps you've seen The Weather Channel and their live crew traveling with the large VORTEX2 armada and you've noticed - "Hey, these guys are NOT showing any severe weather on here - whats up with that?" 

There were many unfortunate meteorological occurances that happened during May 2009 that all played little roles in basically destroying our chances for severe weather.  Now if you don't want severe weather - that's a great thing I'm sure.  But for people like us - people that live, eat and breathe the thought of viewing incredibly structured supercell thunderstorms over the Great Plains - well, we've been left high and dry lately.  In short - the jet stream, which helps produces a strong vertical sheer element in the atmosphere, it went to Canada during May. 

Perhaps it heard that it was going to need a new passport to cross that border so it wanted to get up there why it had the chance.  Or, perhaps it was due to a major low pressure system that came in across the eastern Gulf of Mexico, nearly becoming a tropical depression and combined with a massive dominating high pressure system over extreme southwest Texas - all these things added up and left us with partly cloudy skies, cooler than seasonal average temperatures and just really yucky weather in general.  

High pressure as you probably know circulates in a clockwise fasion.  Look at a map of Texas and put a big "H" over the southwestern portion, and then draw a line starting below that "H" and go clockwise around the "H" until you get to the right of it.  What is happening? The direction that the air is traveling at the surface to the east of the high pressure is generally south - and when this happens, it not only blocks any deep, rich moisture coming up from the Gulf of Mexico, but it also helps push any moisture that might be in the plains back to the south.  Naturally we have to have moisture in the plains to get any really good extreme weather, so you can imagine as long as that big "H" is in south Texas, it doesn't help matters much.

Lets take a look at some forecast guidance, namely the WRF model in its current 72-hour run for 7pm on Saturday (0Z SUN).

Here is the game changer!  A low pressure system starts to dig into the plains during this model run, the wind will start shifing from the south in about 36 hours prior to this event and increasing in speed from Friday night into Saturday.  This in turn will of course carry much needed (for tornadic storms) deep, rich moisture from the Gulf of Mexico northward into Nebraska.

Wow - that almost looks like a real dry line that might develop from northeastern Colorado (aka: The Cheyenne Ridge) back towards Wichita and then towards the southwest.  For those who are trying to learn - notice the area near Wichita where the line bows out? That's called a dry punch, generally it means that a low pressure system is located to the west, while the best moisture will probably located just to the east, or southeast.

At the surface things are looking pretty good so far, but there are still a few things that we need to know. But, before we get into that - let's see what will be happening aloft.  Will the jet stream be there to give us the boost of flow needed for good horizontal vorticity?  

An image is worth a thousand words - so I'll make this part brief. "Big Trough".  This is what will be happening at 300 mb, or about 30,000 feet.  If you're flying from Chicago to L.A. on this day, you're going to be fighting some stout winds most of your trip!  If you're storm chasing on this day, you're going to have an exit region of the jet stream located over northern Oklahoma and southern Kansas!  It's all still good so far!

Let's come down to about 500 mb, or about 18,000 feet and take a look:

 I'm still impressed, but the jet stream and low pressure trough isn't considered "ideal".  This system has been sitting over the Pacific Ocean just off the shores of California for a few days and the low pressure system has already pretty much reached its mature point.  As it moves across the United States the center of the upper-low is still over Nevada while the exit region gets spilled out over the Rockies and into the plains.  This creates a trough axis from SW to NE, or a positive tilted trough.  While the trough itself is very good news, if it were negatively tilted our chances of extreme weather would be taken up a few notches.  Still yet though, its been a rough year and its good to see some flow returning to the plains so that we can refresh the atmosphere with needed moisture!

There is one more thing that I want to talk about and especially since it's June.  The "CAP", this is a layer of warm air that will sit on top of the surface layer and may prevent storms from actually developing at all.  Typically, in June the CAP is pretty strong in the southern plains, and often in the central plains. This is because this layer of warm air gets "pushed" into the plains from higher desert elevations, such as the New Mexico plateau.  By June the air over New Mexico is extremely warm - thus when it moves into the plains it creates a strong CAP.  In order to get storms to develop we'll need some stong instability so that as the heat rises from the surfaces it has enough momentum to break through this warm layer.  The CAP strentgh can usually be measure in the plains by examining the air temperature at 700 mb (just about 10,000 feet).  But we can cheat a little bit and look at this model graphic:

 

This shows us basically two different things - the colored gradients indicate the CAPE (Convective Available Potential Energy) and the hatched areas indicated the CAP or lid strength.  In order to get tornadic supercells to develop we'll generally need at least 1500 j/kg of CAPE, which it appears that we'll have in the central plains.  However there is a problem - there is a hatched area on top of it!  This might mean that any instability that develops won't be enough to punch through the CAP.  Except for maybe a tiny area from about Altus, Oklahoma back towards Abilene, TX - but down here we won't have the upper-level flow that we'll have in the central plains for great rotating updrafts.  Let's examine the CAP strength using a SKEW-T diagram with the model forecasting data.

 

 If you're not familiar with this funny looking chart, it's called a Skew-T/Log-P diagram and its the most useful tool you can take with you when you're storm chasing (in my personal opinion).  Using this chart you can easily intrepret just about anything you want to know about the atmosphere as long as you know a few basic pieces of information to start off with such as the surface temperate and the dewpoint, as well as the general "profile" of each throughout the atmosphere.  There is a great PDF file online from Texas A&M University that can help you get up to speed located here: http://www.met.tamu.edu/class/atmo251/book05soundings.pdf

This particular diagram above is a forecast skew-t based on the latest run of the WRF model for Wichita, KS.  So in short, it's attempting to forecast the atmospheric profile for Wichita in 72 hours.  Naturally, its not exact, but for our purposes of trying to estimate the cap strength its a good start.  

In order to estimate the cap using a Skew-T is extremely simple - locate the height level for 700 mb and follow it across until you intersect the temperature profile.  You'll notice in the diagram above there is a dash line at this location, its because this graphic has already done most of the hard work for you (making it very easy to use when you understand the diagram itself).  What this is telling us is that the temperature at about 10,000 feet is going to be about 12 degrees C, or (if you're an American) about 54 degree F.  That doesn't sound to warm to you and I, but if you're a parcel of air leaving the surface and cooling off as you rise up - it's pretty darn warm!  In order for that parcel to break through this warm air the surface dew point temperature is going to need to be at least 26 degrees C, or (American) 79 degrees F - that's a pretty tall order.  And from looking at the diagram it is indicating a dewpoint temp of about 19 degrees C, so it's not quite there.  Which means that of course - the CAP may be, and probably will be the big spoiler on Saturday afternoon.

I'm going to pretty much leave it at that, but the gist of this is that unless this information changes - we're going to likely be digging south along the dryline where the convective temperature (and closer proximity to the Gulf of Mexico) will help the temp/moisture profile to the point where the CAP won't be such a limiting factor - but the trade off will be less upper-level flow.

UPDATE (23Z June 07): Just wanted to post this radar imagery to show current severe warned cells in the southern target area along the dryline. Not a bad pick from a 72-hour old forecast! 

 

Conditions are finally becoming a bit more favorable across the High Plains for severe weather.   However, the past few weeks have been extremely limited due to lack of flow, lack of moisture and you guessed it - lack of quality storms.  We had been reduced to being extremely happy with rainbows lately - it's not what we're here for, but they still make a great photo!

I've also been experimenting with making panoramic photos.  Click the thumbnail below for a bigger image, and if you think that is big - you should see the full resolution image! I can't wait to print it out on a plotter, I think it's going across the wall in my office.

So what do storm chasers do when the weather is horrible (that is sunny with a light breeze)?  They drive around and take artsy photos of anything that they can pass the time with.   I snapped a few shots of a wind turbine in NE Kansas last week and made this composite image from them.

The weather pattern as of late has been horrible for storm chasing.  We actually went through 8 days of May without even a convective watch from SPC!  We saw a low pressure system come in from the Gulf of Mexico over the Florida panhandle and drift to the WEST into the Missouri Valley - it's almost as if the Earth started spinning backwards.  However, there is light at the end of the tunnel - the long range models are hinting that things will be getting back to a more 'normal' pattern during June.  I hope so!

You know how you can tell when your tour customers are happy? They smile! And, these guys should be smiling after witnessing awe-inspiring storm structure in none other than the roadless Nebraska Sandhills on May 20th  (Tour 4).  Not too mention we just drove through that dark precip area in the background a few minutes before this was taken.

 

 

We started the day off in the southern portion of the Texas Panhandle and drove all day without much stopping to get back into Oklahoma.  We witnessed convective initiation on the southern end of the boundary, just north of Watonga and stayed with this cell all evening long.  We made a group decision to stay with it after dark (great bunch of guys!) and we tracked it due south to near Gracemont when we (me included) could hear the rumble of hunger in our bellies over the rumble of thunder (was on the storm for about 3 hours) - so with it getting ever darker and we were growing hungrier, with food options closing, we decided to leave the storm in search of our only meal of the day.  Wouldn't you know it - not 10 minutes after we leave it, it hosed and an F2 tornado struck Anadarko, OK.

The storm was a big High Precipitation mess and it would have been too dark to have witnessed the tornado anyway - but I guess it's the thought that gets me.    Despite this, the night time lightning from this cell was absolutely phenomenal. I'll post some of those shots at another time.

The storm went through several stages throughout the evening taking on multicellular characteristics and then starting to look a bit more like a real supercell and back to pulse storm, etc...  At one point we witnessed a deep lowering rotating wall cloud with good structure from our viewing angle.  But, despite the tremendous amount of cascading motion and rotation that we witnessed, not much else happened during daylight hours.

 Initial Convection North of Watonga, Oklahoma

The early stages of wall cloud development.

Just north of I-40 over Oklahoma Wind Farm

The base of this storm had a lot of motion in it.