Monday, May 28, 2012

5/28 - 10:30am - Video from Friday's Chase

Check out this video taken on Friday just south of Hays, Kansas during our storm chase. The supercell storm we followed for a good portion of that day had quite a bit of blowing dust and even a few gustnadoes. I wish I could have captured more of the gustandoes, but they were happening very quickly and usually while we were driving. This cell ended up producing a very brief, very small string-like funnel before it dissipated.

Saturday, May 26, 2012

5/26 - 11:35pm EDT - The Journey Home

Storms yesterday in Central Kansas did not produce a tornado for us. We did see a very brief string-like funnel at one point, but that was about the extent of our tornadic sights for the day. There were many tornadoes that touched down with damage reported closer sunset with these storms, but we had to make the judgement call to bug out and get back to Oklahoma City in time for people to get on their flights home before this happened. If these storms had organized a little quicker I think our chances of getting on a tornado would of been much better. The day began with a stop in Russell, Kansas where the Center for Severe Weather Research's ROTATE project happened to stop by for awhile. We were able to visit with them a bit and take some great pictures!

The chase began near La Crosse, Kansas where we followed a couple of developing supercells that had quite a bit of dust kicking out from under their ouflow. We followed a right-moving cell for quite some time, all the way to Bunker Hill, Kansas, as it cycled through weak and strong stages. This is the storm that produced the aforementioned string-like funnel cloud. Many a wall cloud came from this storm, but it was just too disorganized of a structure to get things going for a tornado. The storm that would form quite a few tornadoes (including an EF2-rated one near... you guessed it... La Crosse, Kansas) finally got its act together just to our southwest near sunset, but we had to bug out just as that was happening because we were so far away from Oklahoma City where we needed to be so that our tour guests could fly out. It's really too bad that we had to miss these tornadoes, but that's part of having to deal with the logistics of tour guests and the unpredictability of storm chasing. The storm structures were certainly spectacular though and we did see quite a few gustnadoes and dust being blow around. Video from these storms will be processed and uploaded tomorrow night when I get some time.

Yesterday and today have really been the same day for me. After we finished chasing in Central Kansas we had to make a bee line for Oklahoma City, where we made it in to town just after 3:30am this morning. My flight left at 7:35am this morning meaning I had to be at the airport around 6am, so I actually had no time to sleep in the interim. It's good to be back home in Louisville after being so tired! During these three weeks I've been with Storm Chasing Adventure Tours this month we've gone 8,383 miles across Oklahoma, Texas, New Mexico, Colorado, Nebraska, South Dakota, Iowa, Missouri, and Kansas. There are so many areas that we visited this season that I've never been to before, especially near the Mexican border in Laredo, Texas and Big Bend National Park. But I'm not done yet. After a few weeks at home and abroad, I'll be back out storm chasing again for a week starting on June 23rd and going through the 30th. This is typically a time where severe weather is found up north in the Dakotas and Nebraska, so I'll be flying out to Denver in about a month's time to meet up with everyone. A photo album of this year's chase so far can be found on my Flickr and Facebook accounts along with the slideshow below:

Friday, May 25, 2012

5/25 - 11:50am CDT - A Grand Finale

Ever since earlier this week we've had our eye on today's setup in Central Kansas. The moisture return, a low developing over Southwest Kansas, and upper-level wind support all kept us coming back to look at the models to see how it was shaping up. For a while it looked like the cap, or a layer of instability-inhibiting warm air aloft, was going to surpress storm formation but now we're seeing a situation where there will be just enough break in the cap to allow for a few isolated supercell storms to form. To get surface heating today to break that cap we need to clear out the clouds across Kansas first. A push of dry air at around 10,000 feet is currently moving from Southwest Kansas to the northeast and is eating these clouds for breakfast as you see in the satellite image to the right. We expect this to keep moving throughout the day and hopefully it will clear out the clouds in time to get some serious surface heating going.

The big story here today is the moisture return. For the first time this week we are seeing a situation where dew points will surge into the mid to upper 60's. Yes! This much-needed moisture will be the fuel for storms this afternoon and should give us a much better show than the moisture-deprived low-precipitation storms we've been seeing lately. While we don't have this moisture in the area quite yet, it's streaming in like crazy right now. Strong easterly and southeasterly winds are blowing this moisture into Kansas from Missouri and Oklahoma and will continue doing so throughout the day. Having mostly easterly winds in Kansas right now is a very good thing because this is creating just about optimal low-level shear for rotating supercell storms.

Speaking of wind shear, this will create quite a bit of helicity, or a corkscrew-like rotation of air in the atmosphere. When you combine helicity with instability in an equation you get the Energy Helicity Index (EHI). As I've said before I think that indicies and parameters can be distracting since human analysis is always better than a formula, but EHI seems to be fairly reliable since it is so basic and relies on two very basic ingredients. This afternoon's EHI values in Kansas will be the highest we've seen out here this season according to the Rapid Refresh model. That's some great news for storm chasers because higher EHI values typically correlate with enhanced tornado potential.

The Storm Prediction Center has a Slight Risk for severe storms today from Iowa to the Texas Panhandle and within that a 5% tornado risk in Kansas. This is quite the change from the previously non-severe "general thunderstorm" outlooks that they had been issuing for today because of the concern that strong capping may inhibit storm development. Today is our last chase day out here for Tour 3 and my last day out here until I come back for a week in June. If we could see some good storms today that'd be a great end to the first part of my trip! Tonight once we're finished chasing we'll be traveling back to Oklahoma City where I'll fly back to Louisville from tomorrow morning.

Follow up-to-the-minute reports on our chase on my Twitter and Facebook accounts!

Thursday, May 24, 2012

5/24 - 11:30am CDT - A Repositioning Day

Yep, there's a Moderate Risk for severe storms in parts of Wisconsin, Minnesota, and Iowa today according to the Storm Prediction Center. It's too bad because we simply can't chase there due to the amount of trees and vegetation along with a considerable distance from Oklahoma City where we need to be tomorrow night. Here's the plan then: We're going to drive south from Des Moines to Kansas City and then cut west in Kansas for this evening when we could see some overnight storms with lightning in that region.

Tomorrow still looks interesting to say the least. Right out front I need to say that this setup has a very high bust potential because of all the capping that will be in place. Warm temperatures of 10 degrees Celsius and higher at 10,000 feet (700 mb) will act as this capping mechanism because it will inhibit warm air from rising buoyantly into the layers above for thunderstorm formation. With that said, this cap may weaken just enough for a couple of storms to fire up in Kansas tomorrow. They would likely be very isolated due to the capped environment, so that's definitely a plus here.

We all know by now that the models have not been handling moisture very well lately and tomorrow probably won't be any different. The NAM model has dew points of 65 degrees Fahrenheit and higher in Central Kansas at 4pm CDT. If this is overdone and we see dew points between 60 and 65 degrees it still wouldn't be too bad. An area of low pressure smack dab over the middle of Kansas should help bring some of this moisture in and also create a considerable amount of wind shear for rotating storms, especially near the warm front just south of the Nebraska border. Again, this is all if the cap actually breaks tomorrow. If it doesn't we'll be sweating it out in the sun as we watch cumulus cloud towers fail to rise high enough for storms. Tomorrow morning I'll post again with an update on this potential.

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5/24 - 12:35am CDT - We're in... Iowa?

We didn't think we'd be in Iowa tonight. The storms that formed yesterday (Wednesday) rushed eastward as the cold front in the region decided to push further east than expected. Unfortunately none of these storms really did much because they formed in a linear fashion and didn't have the moisture necessary to get too severe. One of the southern cells in the line just west of Omaha, Nebraska managed to be isolated for a while and generated a wall cloud that triggered a tornado warning. Our only option in this environment was to cross the Missouri River in Omaha and wait for the storms to come to us because it would not be good to have the storms outrun us while trying to find a way across the river. The storms slowed down and died out pretty much at that point so we threw in the towel for the day.

Tomorrow will likely be a travel day back to Kansas or Southern Nebraska as we await Friday's potential chase setup. Storms tomorrow will be up near the Great Lakes in Wisconsin and Michigan and we just don't chase there due to the distance from the Plains and lack of good chase environment up there. Strong capping should keep storms from going up in the central and southern Plains, but we'll keep an eye on that in case that changes. Friday's setup may be decent if capping aloft doesn't ruin it. A deepening trough out in California and hopefully some better moisture return from the Gulf of Mexico should create potential for severe weather. A strengthening low in Southeast Colorado/Southwest Kansas should provide ample surface wind support for rotating storms should this pan out as forecast. The Storm Prediction Center already has a 5% risk area for this in their 3-day severe weather outlook. I'm crossing my fingers that this setup will yield some good storms because Friday is my last day chasing in the Plains until late June!

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Wednesday, May 23, 2012

5/23 - 11:50am CDT - Nebraska or Colorado?

Today we're in the Cornhusker state of Nebraska in search of severe storms. Yesterday's chase in what ended up being extreme southern South Dakota was short-lived as storms that formed up that way south of Murdo, SD quickly dissipated due to a low amount of moisture and contamination of their inflow via a layer of clouds that formed to the south of them. The storm we chased had a nice structure for a few minutes and even put down a bit of a wall cloud before it fell apart.

A cold front situated across the center of Nebraska will be the focus for storms this afternoon. The band of clouds on the satellite image is roughly where the front is located right now and it will slowly sag south and east today. A low forming over Eastern Colorado/Western Kansas should help back the winds out of the east this afternoon here in portions of Nebraska and that will increase low-level wind shear needed for rotating storms as that happens. This low will also create easterly winds in Northeast Colorado, so that may be a secondary target area for today.

We're already seeing some easterly winds beginning to set up in Nebraska this morning and we'll be watching where those develop this afternoon as well. Dew points are still quite low this morning in the upper 50's, but more moisture should move in this afternoon and bump up dew points to around 60 or higher. This is still a bit low for good storms, but we'll probably be better off than we were yesterday in this regard. Dew points in Northeast Colorado won't have to be as high for good storms thanks to the elevation there.

The environment today is rather "capped" as we say, meaning there's a warm layer of air above the surface layer that's prohibiting storm development. As surface heating gets going later this afternoon and into this evening there should be enough energy for updrafts to break through this cap and form storms. This means that storms should be fairly isolated at least starting out, which is a good thing since isolated storms are more organized, more likely to produce a tornado, and easier to chase. Some of these isolated storms may become supercells, and that's exactly the thing we're after since they may produce a few tornadoes today. Storms may condense into one or more lines of storms later this evening as the cap quickly erodes after dark. The Storm Prediction Center has a Slight Risk for severe weather today from Colorado to Minnesota and that includes a couple areas of 5% tornado risk. There's a chance we may bug out on our plans for Nebraska and move to the secondary area you see there in Northeast Colorado, so stay tuned.

Follow up-to-the-minute updates today on my Twitter and Facebook accounts!

Tuesday, May 22, 2012

5/22 - 9:45am MDT - Nebraska Here We Come!

Today's storm setup is tricky because we're dealing with, again, a situation where the moisture is not returning to the region as well as we need it to. The good news though is that the trough that is slowly making it's way eastward will finally be in play today, so upper-level wind support will be there for storms. Let's start with the moisture though. The higher dew points will be in the Dakotas today no doubt, but this is at the surface. With such a short time between being dry and having moisture moving into that region, this moist layer is likely very shallow and confined near the surface even though the short-range models this morning show it a little deeper than before (models have not been handling moisture well at all lately). This means that storms up that way would likely be low-precipitation supercells, maybe to the point where some of them are only putting down virga and not ground-falling rain. The better surface wind support near the low will also be in the Dakotas, but you won't get many, if any, tornadoes if the storms can't get any "meat" on them from the lack of moisture. Dew points in Northern Nebraska may be lower at surface, but we may have an overall deeper layer of moisture there.

The upper-level winds as I said before will be more favorable today than yesterday. The trough moving in will provide fast southwesterly winds in the Dakotas extending down to Northern Nebraska. This should bring in some drier air aloft and enhance wind shear for this afternoon's storms. Today we'll stay on the southern end of these winds aloft so that maybe we can get some deeper moisture coupled with the winds. Hopefully some supercell storms can form in this environment.

Because the models are having difficulties resolving moisture issues, today's CAPE (instability) forecast looks rather low in Nebraska with higher values north. This is something we'll be watching throughout the afternoon to see where it actually sets up. The potential lack of moisture and the best shear being removed from deep layer moisture will likely limit tornado potential today, but maybe we can see some high-based photogenic storms!

The Storm Prediction Center has a Slight Risk for severe storms today in the Dakotas extending toward Northern Nebraska. There's only a 2% tornado risk with this and I think this is a good call given the moisture issues here. If dew points were to be higher over a deeper layer in North Dakota I think you could have a pretty decent tornado risk from supercells given the forecast wind environment. In any case, our more southerly target today will put us in great position for tomorrow's chase, which will likely be in Nebraska.

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