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!

Follow me on Twitter and Facebook for updates this week.

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.

Follow me on Twitter and Facebook for updates today!

5/21 - 11:55pm MDT - Nice LP Supercell Today

Today didn't turn out to be the best chase, but we made the best of it with the sighting of a nice low-precipitation (LP) supercell near Grande, New Mexico. This formed within a line of discrete storm cells that stretched from Southeast Colorado to Central New Mexico. The formation of these cells in a line among an environment characterized by northwest wind flow at 18,000 feet (500 mb) didn't make for the best conditions for severe storms, but a few of them did reach severe limits. Besides this low-profile supercell and possibly a couple others in the same line, an "out of the blue" classic supercell formed ahead of an eastward-advancing MCS (mesoscale convective system - line of storms) just west of Amarillo before being ingested by the actual MCS. It didn't form in the expected environment for this, so we were not in position to see this short-lived storm. More photos of the LP supercell we saw today are available on my Flickr and Facebook albums.

Our tentative plan for tomorrow is to head to the Valentine, Nebraska area to intercept a severe weather threat that may manifest up there as a large-scale trough begins affecting the Northern Plains. Many would consider this an "secondary" target area since higher dew points and better surface winds will be in North Dakota, but in this case the moisture up in North Dakota will likely be confined to an area closer to the surface since there will not be enough time for ample deep moisture to make it up that far north. Northern Nebraska should have some deeper moisture than North Dakota and even though less helicity (spinning motion in atmosphere) will be present in Nebraska, Energy Helicity Index values are still forecast to be elevated according to the Rapid Refresh model. We'll make a final determination based on data coming in tomorrow morning before heading out!

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Monday, May 21, 2012

5/21 - 11am CDT - A Bit of a Surprise This Morning!

Yesterday evening we saw a wonderful view of the annular solar eclipse just south of Lubbock, Texas. This was my first solar eclipse and even though clouds obscured our view of the maximum "ring of fire" portion of the eclipse, it was a spectacular sight. It was good that we had an eclipse because the storm threat that we were targeting in that area was never realized. A good convergence boundary formed and intensified quite a bit, but it seems the "cap" (warm layer of air aloft) was too strong to get any good storms going. There was one small storm that formed to our east, but it quickly dissipated since it was moving into cooler air.

This morning we're waking up to some very good news. Last night's model runs, particularly of the Rapid Refresh, were quite pessimistic about today's setup in Northeast New Mexico and the western Texas Panhandle but early this morning things changed around considerably. The main difference here that I've noticed is the amount of moisture that will be available in this area. For example, the 4z run of the RAP model late last night had dew points near 50 degrees in Northeast New Mexico. The 13z run of the same run this morning has dew points from 60 to 65 degrees. That's a huge difference! Right now the dew points in the northeastern section of New Mexico are in the mid to upper 50's, so the newer runs of the RAP model with the increased moisture are looking good since higher dew points will move in this afternoon.

Having these higher dew points is so important because this moisture is pure thunderstorm fuel. Putting more moisture into the air near the surface increases instability because you have more latent heat contained in the  air as it rises. As such, the CAPE (instability) forecast on the RAP model has responded very positively to the model's higher "correction" in dew point this morning and we're looking at a situation where instability should be quite good at just under 3000 J/kg in most spots around Northeast New Mexico, parts of Southeast Colorado, and the western Texas Panhandle. This is pretty good!

Now that we've cleared moisture and instability for take-off on this event, let's go over what the winds will be doing. The change in the surface wind forecast between last night and this morning hasn't been as great as the change in dew point, but we're still seeing some differences. Winds today will mostly be out of the south-southeast or southeast in the region, with some places especially in Northeast New Mexico seeing a more easterly wind vector than what models were showing yesterday. Storms today will be forming in what we call upslope flow, so having more easterly winds blowing up the higher elevations in this region should create an ample source of lift. This should also increase wind shear a bit due to a contrast with the northwesterly winds aloft at 500 mb (18,000 ft) and create the potential for more organized, isolated storms. When you couple helicity, which is spinning in the atmosphere that takes wind shear to create, with the increased instability that we'll be seeing in a mathematical formula, you get an index called the Energy Helicity Index (EHI). I usually don't look at indexes and parameters too much since they get in the way of looking at the basics behind a storm setup, but EHI is one I do like because it's simple and gives you a decent idea where a tornado threat may set up since helicity and instability are so important. Values last night were slim to none on the models for EHI in our target region, but today with the increased moisture creating more instability we're seeing a marked upswing in forecast values to 2 or more in places.

Even though these values are higher than previously thought for today, we're still not looking at any sort of severe weather or tornado outbreak here. What we are seeing is increased potential for an isolated, organized chance for severe weather in this region that may carry a bit of a tornado threat with it. Right now we're monitoring current conditions across the area and picking out where storm formation may first occur. We drove through some storms this morning on our way from Lubbock to Amarillo as you see on radar there to the right, but those are clearing and the majority of the western Texas Panhandle and Northeast New Mexico is now clear from the rain. A pretty shallow cloud deck is hanging around in Northeast New Mexico at the moment, but there should be time to burn that off and create instability from the heating of the day this afternoon.

Taking all of these factors into account, the Storm Prediction Center has issued a Slight Risk for severe weather in portions of New Mexico, Colorado, Texas, and even the extreme western Oklahoma Panhandle. The Slight Risk includes a 2% tornado risk due to the increased shear and instability that's expected this afternoon that could create some supercell storms. I'm not a big fan of the northwesterly winds aloft at 18,000 feet today because you generally want southwesterly winds up there to bring in drier air aloft and enhance wind shear a little bit more, but this will have to do today. We've seen decent storms with this kind of upper-level wind situation before so it's not enough to rule anything out. It's nice to be able to chase on a day when we thought we would not be able to, so anything we see today will be icing on that cake!

Follow my updates today on Twitter and Facebook for the latest.

Sunday, May 20, 2012

5/20 - 11:45am CDT - Texas Panhandle Today

We're on the road from Oklahoma City to the Panhandle region of Texas where storms are likely to form today. Right now we're watching a clear area on satellite near a cold front situated just south of a line from Childress to Lubbock, TX. This clearing should help to build instability for storms to form as heating from the sun is allowed to reach the surface. Winds and dew points at the moment are not terribly favorable, but the most recent RAP (Rapid Refresh) model does have surface winds turning more easterly during the afternoon bringing in more moisture.

Even though winds at the surface will likely be favorable, winds aloft at 18,000 feet (500 mb) will be weak and westerly to west-northwesterly. It would be preferrable to have winds at that level that are fast and from the southwest, so not having much of either of those components will be a limiting factor. Storms that form this afternoon could have some large hail and winds, but the tornado threat at the moment looks marginal given the lack of upper wind support and possibly lower dew points.

Given these factors, the Storm Prediction Center has decided to forgo issuing a severe weather risk for the area today and only has a general storm risk with mention of some isolated instances of severe storms. The trick today will be to find these isolated instances wherever the best environment for these sets up this afternoon.

The latest updates on our chase are available on Twitter and Facebook.

Saturday, May 19, 2012

5/19 - 11:30pm CDT - New Tour Group, Chase Tomorrow

This morning Tour 2's guests departed and this evening we just finished up orientation and dinner with the guests on Tour 3. This past week we went 2,402 miles (3,866 kilometers) across Oklahoma, Texas, Colorado, and Kansas. Everybody had a great time as we traveled from the Mexican border near Big Bend National Park in Texas all the way to Denver even though storms may not have been available to chase every day.

A rash of tornadoes southwest of Wichita, Kansas near Harper has us a little down this evening since they happened during our day to switch up tour groups in Oklahoma City. Unfortunately there was damage reported with these tornadoes, which seemed to be all rope-like based on the photos being posted via social media. The rope structure of these makes sense given the low moisture in the area which means that cloud bases were high. For tomorrow the setup does not look as favorable for tornadoes given the still marginal amount of moisture in the region and weaker upper-level winds, but our sights are set on Western Oklahoma and the Panhandle region of Texas as the cold front that triggered today's madness continues southward.

The Storm Prediction Center has a general thunderstorm risk with a 5% severe probability for the area in question tomorrow. They're not real optimistic about severe storms based on the weak upper-level and surface winds, but we'll see how that develops tomorrow. The one thing we have going is that the direction of the winds at the surface (mostly easterly) will contrast well with the mostly westerly winds at 500 mb (18,000 ft) for some directional wind shear. Good storms may be hard to come by on Monday, but as the trough that I mentioned in the previous blog post begins to move in I think our prospects will improve during the week.

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Friday, May 18, 2012

5/18 - 2:45pm CDT - Regarding Next Week's Chase

As we make our way back to Oklahoma City on our last day of this week's storm chasing tour, I'm looking over quite a bit of data for next week's severe weather potential. After a lengthy period of high pressure ridging across the Plains (A.K.A. no storms) we're finally seeing signs that a large-scale trough will begin to move onshore from the Pacific and begin to affect the Plains during the middle part of the week. A smaller trough will be coming through this weekend as well but not a lot of moisture and our inability to chase during its peak on Saturday due to our down day in Oklahoma City means it will not be discussed here.

This trough coming in next week will need some moisture to work with for severe weather to form. This is something we've had a problem with for a while now but it looks like the Gulf of Mexico will finally be "open for business" starting next week. As the trough begins creating southwesterly winds and diffluence aloft in Kansas extending into Northwest Oklahoma on Wednesday (5/23), southerly winds at the surface should begin to bring in some much-needed moisture. The degree to which this will happen is still very much up in the air at this point because the GFS model has been consistently overshooting actual dew points, meaning it's been too optimistic about moisture return. The European model does agree that moisture will begin flowing into the Plains on Wednesday, but to a lesser degree than the GFS on the right.

This setup will continue right into Thursday and Friday as the trough digs in and moisture continues to flow into the region. These two days may harbor better severe weather chances than Wednesday due to having more time for moisture to return. Given the possibility that small-scale weather phenomena like cloud shields and overnight storms could limit potential on any of these days it's very difficult to point out which of them will be the best for storm chasing. Not only that, but the aforementioned computer model issues and amount of time between now and the trough moving into the Plains creates an even bigger margin of error. It's safe to say right now that things are certainly looking more favorable synoptically (on a large scale) for severe storms, but calling for a tornado "outbreak" at this point wouldn't be logical due to the variability of all the smaller features involved. This setup certainly has our attention and we're keeping close watch! Our robotic streaming webcam has been sitting dormant since we haven't had any storms lately, but we're hoping that we can put it in action next week.

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Thursday, May 17, 2012

5/17 - 4:15pm MDT - Some Fun in Denver!

Since good storms for chasing didn't form yesterday and won't form today, we're having a bit of fun in Denver, Colorado! Today we split into a few groups, one group that toured the Front Range of the Rockies, one that went to the Denver Art Museum, and another that went to the Elitch Gardens theme park in town. We all had a great time and will meet up this evening for dinner. Tomorrow we'll be heading back to Oklahoma City as Tour 2 ends and we'll be saying goodbye to our guests on Saturday morning.

For next week's tour, Tour 3, there may be a return of severe weather to the Plains. This may take until midweek though as a large-scale trough moves inland from the Pacific and moisture flows back into the region near the surface from the Gulf of Mexico. A lack of moisture in the Plains has plagued us for days now, so this return will be very welcome if what the long-range GFS model indicates pans out.

Be sure to keep up with my updates on Twitter and Facebook!

Wednesday, May 16, 2012

5/16 - 10:45am CDT - To Colorado We Go!

After spending quite a bit of time in Texas over the past few days we are on our way north to Colorado this morning. We're going to try to chase some storms that may form in the upslope flow of the Front Range of the Rockies. Here's how these form: Moist air flows from east to west up the gentle slope of the mountains during the afternoon. This moist air when lifted by the terrain condenses because it's moving into cooler air aloft. As more air rises up this gentle east-west slope, it continues to condense to form clouds and eventually thunderstorms. Since the mountains act as a constant source of lift, these storms can be pretty reliable as long as other ingredients are in place.

Here's the issue for today though... Moisture is going to be hard to come by today because the last major system to roll through the Plains last week pushed all the moisture down toward the Gulf of Mexico. A little bit of it will be returning to the region today though and we can already see that happening on the current surface map. Dew points right now are in the 30's with a couple 40 degree plus readings across the eastern part of Colorado where these storms will form. In a perfect world you'd want easterly winds to be blowing in better moisture and to create better low-level shear, but this morning we're dealing with southeasterly winds. The good part is that it doesn't take as much moisture to generate these storms as it does in lower elevations. Generally you want dew points to be above 40 degrees in this region, and that's something we may struggle to get today if the computer models are correct.

Putting all of this together with some weak southwest winds at 500 mb (18,000 ft) there is a chance for some storms in Eastern Colorado today. With potentially weak moisture return the setup for anything severe looks very "iffy" at this point and the Storm Prediction Center has placed parts of Eastern Colorado under only a general thunderstorm risk because of this. We'll keep an eye on the surface observations this morning and afternoon to determine whether moisture will return as needed.

Last night I had a good internet connection at our hotel and was able to upload some video. Check out my footage of our encounter with golf ball size hail and flash flooding east of Lajitas, Texas on Monday:

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Tuesday, May 15, 2012

5/15 - 11:30am CDT - Excitement in Southwest Texas Yesterday

My apologies for not having a blog post last night. We're in the Big Bend National Park area of Texas and there was little to no cellular data service where we stayed last night. Our travels along the Mexican border region of Southwest Texas yesterday were quite exciting though. We started off in Pecos, Texas and traveled south to Paradisio, Texas right on the border. We waited here for some storms to form before heading eastward to intercept them. Most of these storms were clustered together, but there were a couple cells that stayed independent that came toward us and crossed the border. The tornado threat wasn't realized yesterday because low-level shear did not play out as forecast due to unfavorable surface winds and multiple storms contaminating each other with cold outflow air. As we drove on the mountainous road along the Rio Grande river (yes there was a certain Duran Duran song of the same name stuck in my head) there was not much cell service so we had very limited radar updates. We drove east of Lajitas, Texas as the strongest cell at the time came at us rather quickly with no escape. Our vehicles pulled to the side of the road near a rock wall and that shielded us from the brunt of the golf ball size hail that came down.

This storm put down a huge amount of rain, so much so that the residents in this area that we talked to hadn't seen something like it in over four years. The deluge quickly overwhelmed the ground and widespread flash flooding took place. Our road east along the border was flooded by a foot of water at one point, so we stopped for an hour to let the water level drop. 6 or more inches of water is dangerous to drive through. The rushing rapids going over the road brought some pretty big rocks and debris, but luckily none of this was too big for a hand toss to the side of the road. Our group then continued on to a town just outside the Big Bend park area where we spent the night. I have some great video of the hail and flood yesterday that I'll try to upload once we get to a hotel with internet service.

Today's storm setup in Texas looks very marginal so we're touring the Big Bend area and then heading north so we can be ready for storms that may form in Eastern Colorado later on this week. With limited moisture in the Plains it might be hard to find some good storms over the next few days. We'll make the best of it!

Keep up with our chase by following me on Twitter and Facebook.

Monday, May 14, 2012

5/14 - 12:45pm CDT - Pressing Further Southwest in Texas

Today we're continuing on southwestward in Texas where fast westerly and northwesterly winds aloft and moist, easterly winds at the surface will combine to create a potential for severe weather. These winds should create enough shear for supercells among some scattered storms and more specifically there is a chance for a couple tornadoes down this way. There are a few clouds on the visible satellite view right now from ongoing storms in the region, but areas closer to the Mexican border near Marfa and Fort Davis are pretty much cloud free. There is a field of cumulus clouds we're driving toward south of Marfa that may serve as a focus for development, so we'll see how that pans out. In any case we have lots of direct sunlight and instability already building for storms later this afternoon.

The Storm Prediction Center has issued a Slight Risk for severe weather today across extreme southwest Texas where we're at and they've even included a 5% tornado risk area. This is the best setup we've had so far this week, so we remain hopeful that we'll see some great stuff today! There aren't many roads around the area so this will be a challenging chase day even though the ingredients appear to be coming together pretty well.

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5/14 - 12:30am CDT - Great Lightning Tonight in West Texas!

We were treated to a great lightning show just north of Pecos, Texas earlier this evening as a few isolated storms merged together to create a fast-moving line of storms (MCS) that quickly caught up with us. These storms packed some very large hail and high winds at their peak, but luckily we were able to stay ahead of them during that time. The storm kicked up quite a bit of dust in the gust front, so it created low visibilities and an eerie scene in Pecos as it moved through. This comes after a day of fruitless chasing because storms that were expected to form near the Midland, Texas area did not due to a lack of required surface heating. More photos of this storm are available on my Flickr and Facebook albums.

Tomorrow we'll likely be chasing in West Texas again, but this time it may be closer to the Mexican border. Fast winds aloft, moisture at the surface, and winds blowing up the mountains in Mexico from the east should trigger some storms tomorrow afternoon after the ones tonight move through. The setup will be relatively similar to today, but hopefully we're able to get some more stronger isolated storms out of this. Here's some of the high points from the Storm Prediction Center's discussion on tomorrow with their Slight Risk area:
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