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!

5/11 - 11am CDT - A Crazy Chase in South Texas Yesterday

Our timing yesterday was just about perfect. As we surged southward from Carlsbad, New Mexico to the Del Rio, Texas area we began tracking storms that were forming in the mountains of Mexico near the Texas border. One fairly supercell formed along a boundary of converging wind just north of Laredo, TX in Mexico and we knew that this was the storm we needed to chase. It merged with another supercell that was moving north quickly to create a big storm with some intense rotation. We were able to get to the south side (where a tornado would be) just in time so that the hail and intense rain wouldn't cut us off from our road down to that area. Once we were there we saw some definite rotation and a couple wall clouds, but the storm was moving fast so we had to keep moving toward Laredo. We pulled over in a parking area just north of the city and continued to watch a wall cloud form that had a tiny hint of a funnel cloud in it. It was so small that it was barely visible, but it was certainly in rotation and was on the correct part of the storm. That was about all the storm had to offer tornado-wise.

By the time we made it east from Laredo the storm had merged with others to form a line of storms called an MCS (mesoscale convective system). This pretty much killed the tornado risk for this storm so we watched a very impressive lightning show from it as the sun set. Given the excitement that we had while chasing the storm while north of Laredo yesterday, it was a pretty good day! You can find more storm chasing photos from yesterday and earlier this week on my Flickr and Facebook albums.

Today we're traveling back to Oklahoma City so that our guests on Tour 1 can depart on their flights tomorrow. Tour 2 starts tomorrow night with our orientation and then we set out on Sunday for another week of storm chasing!

Follow me on Twitter and Facebook anytime for storm chasing updates.

2/22 - 3pm - Severe Storms Possible Tomorrow Across the South

Let's start with today first. It's unbelievably nice outside! You can't get much better than this in February in North Mississippi. You may be thinking that we'll have to pay for this great weather with some sort of severe weather event, and you're correct. This warm, moist air will serve as the fuel for a few severe storms across the region tomorrow night (see right for the SPC's latest Slight Risk area).

The main issue with the forecast at this point is where and exactly when will these storms form? The computer forecast models are having a difficult time figuring out if a warm layer of air aloft will serve to suppress storm development during the evening. This layer of air, which is called the "cap", is something that storm chasers in the Plains have to deal with quite often but usually not something we deal with here in the Southeast. Even though the models are having a hard time with this, we'll likely see a squall line of storms (QLCS in weather nerd lingo) roll through sometime around or after midnight tomorrow night. These will likely carry wind damage and hail threats, but the latest data coming in suggests that we may even see a couple isolated tornadoes. This will certainly not be a tornado outbreak by any means because the wind shear profiles for that kind of thing just aren't there. The energy helicity index (a combination of rotation in the atmosphere and instability) output on the left from the 18z NAM shows that this squall line will have some tornado ingredients to work with, but not all that much.

Another reason why we won't see a more significant severe weather risk is because the amount of moisture that we'll have filtering into the region from the Gulf won't be as strong as previously thought. Dewpoints just above 60 (on right) are certainly enough to trigger severe storms, but something closer to 70 is needed for more potent setups. Check out the video below for more details on this system:

6/27 - 11:15am - More Severe Weather for KY and IN

Had enough storms already? We have one more round to go before we clear things out for a while around Kentucky and Indiana. A few non-severe storms have already moved through the Louisville area this morning and the storms that are still well off to the west are weakening and beginning to take a more southerly turn.


The bit of clearing we'll see this afternoon after this morning's storms pass off to the east should help to destabilize the atmosphere in preparation for development of severe storms this afternoon. If this clearing doesn't materialize and we stay more cloudy than sunny across the area, the severe threat will be much lower. These storms should fire up in the mid afternoon across southwest Indiana and Western Kentucky and impact the Louisville area this evening. While most of these will be your run-of-the-mill severe storms with 60mph winds and hail, a few could have supercell structures or bowing segments. The embedded or isolated supercell structures will be powered by the small amount of wind shear (changing wind direction and speed with height - see 5pm NAM model output left) and helicity (turning in the atmosphere) we'll have in the area as storms form. This means a couple isolated tornadoes are possible.

The bowing segments could produce wind damage as a cold pool of air collects behind some of the more linear storms. These storms will likely last well into the evening and overnight hours and be out of the Louisville area by mid morning tomorrow or earlier. Since there is the risk for wind damage and an isolated tornado or two, the Storm Prediction Center has issued a Slight Risk area for most of Kentucky, Southern Indiana, and portions of Middle Tennessee. A 5% tornado risk exists from Chicago and St. Louis to along the Ohio River, while a 2% risk extends further southward.

6/25 - 2:45pm - Tomorrow's Entertainment: An MCS

An MCS or Mesoscale Convective System is scheduled to move through Kentucky and Indiana tomorrow morning. An MCS is basically a large cluster of storms that normally has a distinct wind-driven line of strong to severe storms on the east side as it pushes along at a decent speed. Tornadoes can sometimes form in little notches or "eddies" that develop in the strong line of storms on the east or leading side of the MCS. Given that there will be some helicity (turning in the atmosphere) from Indianapolis to Bowling Green, KY as the MCS moves through, it would not surprise me to see a Tornado Warning or two issued since there could be a little rotation aloft. This will not be a tornado event though and I expect the probability of tornadoes to remain low. This will not be an event like Wednesday when we had five tornado touchdowns in the area because we will not have supercells developing. The Louisville area can expect storms to start sometime around 7am and possibly last into the mid afternoon hours. While the initial line of storms in the morning could be strong or severe, heating during the day could intensify storms by around noon. The main threats from this complex of storms will be damaging winds (especially in the morning) and hail. The 12z NAM model run (top left) seems to have a good handle on the storms.

These storms will be driven by a mid-level shortwave trough, which is basically just a ripple or wave in the atmosphere, and a warm front rising northward. Once this warm front passes to our north tomorrow, we can expect temperatures to exceed 90 degrees again next week.

We're under a Slight Risk tomorrow from the Storm Prediction Center (left) and on the very southern edge of another one on Monday (right) since another line of storms may try to come through early in the day:

Be sure to scroll down and read my exhaustive post on the Louisville tornadoes that happened on Wednesday.

5/31 - 12pm CDT - Minnesota? / Back to Nebraska

We're departing Detroit Lakes, Minnesota for Nebraska this morning. Many of you are probably asking how on earth we ended up in Minnesota last night. Here's the deal: The area of low pressure that we tried to stay up yesterday with kept moving northward and we had to follow it into the Fargo, North Dakota area. The cap (warm layer of inhibiting air) was broken with 4500 J/kg CAPE (!) for nearly four hours yesterday, but the low kept moving around. This meant that the east wind component needed for supercell formation wasn't staying in the same place either, so elements just weren't lining up in one spot for a long enough time to get anything going. Once we finally threw in the towel, we headed just a few miles east to Detroit Lakes, Minnesota for a nice evening in the town with a view of the lake.


Not all was lost though, because we did have a fast-moving squall line of storms move through Detroit Lakes while we were eating dinner. We had heavy rain and lightning where we were, but just a few miles west in Fargo, ND they sustained some wind damage due to a bowing segment in the line of storms.


Westerly flow aloft and southeasterly winds at the surface will return to Nebraska/South Dakota tomorrow as an area of low pressure moves into Colorado. These winds at the surface should usher in dew points that will break 65 degrees, so moisture should not be a problem as it returns to the Plains. Instability also looks good and it appears the cap will break tomorrow in the later afternoon hours. With all of this put into play, the Storm Prediction Center has issued a 15% Slight Risk area for severe weather in Nebraska, parts of South Dakota, Minnesota, and Iowa. They even have a hatched area for an enhanced risk and their discussion calls for supercells with a few tornadoes possible. Looks like the chase is on again tomorrow!

4/3 - 5:40pm - Severe Weather Tomorrow Across the South

The Bottom Line

Central/North Mississippi: Severe weather will be possible starting in the late morning hours tomorrow and extend until likely just after 7pm. Supercell thunderstorms could form in front of a main squall line in the early afternoon and produce some tornadoes, but this will be highly dependent on some "iffy" factors like the cap and surface winds. Straight line wind damage, large hail, and some embedded brief tornadoes will be possible with an approaching squall line of storms as we get closer to sunset.

West Tennessee: A squall line of storms will travel from west to east tomorrow between the late morning and middle afternoon hours. This line will strengthen due to daytime heating as it travels eastward, so be especially on the lookout if you live east of Jackson, TN. There's also a possibility for the development of a supercell or two in the southern portions of West Tennessee before the passage of the main line of storms. Straight line winds, hail, a few brief tornadoes, and flash flooding will be possible as the squall line passes through.

Follow me on Twitter or Facebook for updates on tomorrow's severe weather.

Details

Severe weather will be an issue tomorrow around the South as a sharp trough and accompanying cold front advance eastward. The Storm Prediction Center has already put a large portion of the Southeast US under a Slight Risk for severe weather tomorrow, putting particular emphasis on an enhanced severe threat in Mississippi, Alabama, and Tennessee with a 30% outlined area. The SPC's outlook calls for the chance of discrete superecells in front of a main squall line, or QLCS, of storms that could bring damaging winds and some embedded tornadoes.

Here in Mississippi and West Tennessee we'll be watching for a particular area where the most favorable wind shear and instability will come together to create the greatest threat for severe weather. Wind profiles will be most favorable for severe weather as you go northward into Tennessee and Kentucky, but instability will be strongest over Central and North Mississippi as we head into the afternoon hours tomorrow. The meeting of these two "peak" areas of winds and instability will likely be North Mississippi into North Alabama and extreme Southwest Tennessee. The SREF computer model's Significant Tornado Ingredients parameter on the image to the right shows a pretty good estimate of where this area will be during the afternoon tomorrow in the 20 and 30 outlined areas.

To the north of this area straight line winds and brief embedded tornadoes will be the greatest threat as the squall line pushes through during the afternoon. Inside and slightly south of this area is where the best chance for front-running discrete supercells could be. These supercells, should they form, will have a risk of producing tornadoes and large hail. Surface winds from the south or southeast will be needed to produce these tornadoes, so that's certainly something to watch for. Sunlight during the late morning and early afternoon will be the fuel for these supercell storms and the "cap" (warm layer of air above the surface that blocks air parcels from rising and creating thunderstorms) will be crucial. The NAM model indicates that the cap will break and allow for storm development sometime in Central and North Mississippi between 10am and 1pm tomorrow as you'll see on the left. Forecasting when and if a cap will break is extremely tricky, so don't be surprised if we get lucky and supercells don't form due to a stronger than anticipated cap.

Instability in general will be quite adequate tomorrow across Central and North Mississippi as dry air aloft will allow rising moist air parcels from the surface to continue upward, which is the main mechanism for building thunderstorms. The NAM model sounding at 7am tomorrow on the right indicates where this dry air is in relation to the moist air at the surface.

The timing of when the main line of storms will come through has been an issue on some of the computer models. The SREF and NAM models seem to be in agreement that the severe weather threat will begin sometime after 10am in North Mississippi with the potential for front-running supercells and then having the main line of storms come through Northeast Mississippi near the 7pm hour. The GFS has been a little quicker with this, but it seems the last couple of runs have put it more in agreement with the NAM/SREF and the ~7pm timing of the main line coming through Northeast Mississippi.

With the threat of supercells in the early afternoon and the squall line near nightfall, this will be a fairly long event. There isn't one particular parameter that sticks out as being "historic" or much above average for any severe weather event. The significance here is that each of these parameters (instability, shear, moisture, etc) will meet the required criteria for severe weather and converge over a good chunk of Mississippi, extreme Southwest Tennessee, and Alabama. I don't think there will be a large tornado outbreak of any sort, but tornadoes could be possible in both the front-running supercells and main squall line.

Be sure to keep those NOAA weather alert radios in "alert" mode tomorrow if you live within the SPC's 15% or 30% risk areas. Even though this severe weather event will not break any records, it has the potential to affect a large population and cause damage.

7/18 - 3:45pm - Slight Risk for Severe Weather This Evening

The Storm Prediction Center has issued a SLIGHT Risk for severe weather this evening, with the main threat to the Louisville area being high winds. A squall line of storms has been developing this afternoon to our west and should be coming through here sometime after 4:15pm. An embedded cell within this line near English, Indiana has reached severe limits and I do expect this line to strengthen given the highly unstable environment and moisture available in the region. Once this line comes through, we may see a few scattered storms develop tonight due to enhancement by the low-level jet.

Since a cold front will be stalling out south of Indianapolis tomorrow, we'll see another good storm chance on Monday and Tuesday. The Storm Prediction Center has placed us under a 15% SLIGHT Risk for severe storms again tomorrow, with the main risk being high wind again. After another 90-degree day on Monday, temperatures will bump into the mid 90's for the remainder of the week.

5/14 - 11:30pm CDT - Heading Back to Amarillo

We're on the road to Amarillo, TX right now so that our current tour guests can fly out in the morning and our new guests can arrive for Tour 3. It's been a great week out here in the Plains, and we're just getting started! We'll be chasing again on Sunday, most likely in Texas again like today and yesterday. There aren't any big severe weather outbreaks on the radar for this week, but we'll see what we can turn up!

Today's chase was very interesting to say the least. Supercells got going near Kermit (the Frog?), Texas just after the noon hour. This early firing caused by a weak atmospheric cap nearly depleted tornado chances because the environment became cluttered with cells very quickly and the maximum heating of the day had not occurred yet. We tried to intercept a very strong cell that formed close to us, but road options were terrible and we could not make it to the updraft base before it merged with adjacent cells. This supercell did produce a brief tornado according to chaser reports and photos that were sent in to local media. Another supercell then formed to the southwest in the warmer air to the south of the cold front and that one showed quite a bit of promise for over an hour. Like the last cell though, it perished as cool outflow air from other storms corrupted it and caused it to merge with the squall line that had formed. VORTEX2 was on this second cell and we saw their vehicles all over the place. The TIV2 (Tornado Intercept Vehicle 2 - IMAX film production crew) even zoomed by us as well.

Once all the storms joined into a linear complex, we punched north through it and headed for dinner in Odessa, TX. About half an hour after dinner on the way to Amarillo we saw a compact supercell on radar in the cool air behind the cold front. Intrigued by this strong little cell that was along our route, we pulled over to watch it. It dropped one inch diameter (quarter-sized) hail and did not have much rain at all. The sunset pictures of this cell were just gorgeous (see right) and we let the storm pass over us after parking under a gas station overhang. I think everyone is still trying to dry out after getting pelted with small hail and brief heavy rain as we stood outside to watch the storm pass.

I'll upload some video of each storm event as soon as we arrive in Amarillo and have it posted here.

10/25 - 3:15pm - MSU Forecast

Here's your latest Mississippi State University forecast:


Sunny skies should stick around until Tuesday, when severe weather might be an issue. A squall line of thunderstorms will most likely come through the area on Tuesday afternoon or evening, packing with it some strong wind and heavy rain. I don't think this will be a tornado-type of event, but more of a fast-moving windy thunderstorm type of event. A sunny day will follow on Wednesday with more storms on Thursday and Friday. Things should clear out on Saturday after a small chance of morning storms.

The MSU vs. Florida game last night was a blast, but unfortunately MSU just couldn't outpace No. 1 Florida. Great effort though!

5/15 - 10:30pm - Storms Late Tonight?

A line of severe thunderstorms is crossing Illinois and Indiana right now and is building southward and staying pretty strong a bit unexpectedly:


There are no tornado warnings at this point with this line of storms, but there are some Severe Thunderstorm Warnings. The SPC is beginning to think that a Tornado Watch in Indiana may need to be extended southward into our area (we'd be on the southern fringe) in their latest mesoscale discussion:

Don't be surprised if we get a Tornado or Severe Thunderstorm Watch in the next couple hours, but I'm thinking these storms will weaken before they get here.

2/10 - 5pm - SLIGHT RISK, HIGH WIND WARNING

Here's the latest convective outlook from the SPC:



We're under a 30% chance for severe weather tomorrow, which is at the high end of a SLIGHT Risk. We were under a 45% chance earlier today, but that they have since lowered that. A squall line (thin line of severe storms) will be coming through tomorrow afternoon sometime with high winds and the possibility of a few tornadoes. If the sun comes out tomorrow before this line comes through, expect a heightened level of severe weather.

The High Wind Warning will be from 7am until 10pm tomorrow. This has been put in place because we could see constant winds of 40mph with gusts to 60mph just before and after the squall line passes tomorrow afternoon. The squall line itself could generate wind gusts well over 70mph if it becomes severe enough. At any rate, winds should start to pick up tonight and last through the day tomorrow. As for power outages, I do think there will be some around the area. The number of power outages will depend on the wind speeds tomorrow.

One more day in the 60's tomorrow before we drop into the 50's for the rest of the week.

2/8 - 11am - Squall Line?

Take a look at what the SPC just issued for Wednesday into Thursday:



At the moment, the SPC is thinking there will be a squall line (thin line of severe storms, usually packing high winds) east of the Mississippi River on Wednesday based on a front coming through with high dewpoints, indicative of a high level of moisture in the air. Instability will remain marginal at best according to the latest SREF, with the highest concentration remaining just to our west during this event. If we stay overcast the whole day on Wednesday, then instability will certainly be low. A sunnier day on Wednesday could spell trouble. A little bit of shear may come into play around here, but I think that will stay in the deep south. Overall, I think we'll see a fast-moving squall line come through here on Wednesday afternoon or evening, but it shouldn't be too bad. The main threat would be wind damage, but really nothing else because the line should be decreasing in intensity as it comes our way.

I know the clouds and showers weren't a great way to start the day, but temperatures will increase a couple more degrees this afternoon and it looks like we will see some sun. Tomorrow is shaping up to be even warmer than I thought, with highs around the area now expected to top out in the mid 60's! The warm air coming up from the Southeast should stick around for Tuesday and Wednesday, but that supply of warm air will get cut off as the cold front comes through on Wednesday night.

My next blog post will be late tomorrow evening... you'll want to check back for that one.

6/27 - 9:30pm - Here Comes a SQUALL LINE!

We're under a Severe Thunderstorm Watch as a nasty looking squall line is getting ready to bear down on us. It should be here within the hour, since it's moving at 55mph. I can't do any severe weather video streaming since I'm still getting things ready for tomorrow's event. The worst this line will do is generate some half inch hail and possibly some pretty gusty winds. There is a tornado warning out for Orange County, IN... There is some pretty strong rotation there, so folks need to take cover up there. We're OK it looks like on the tornado situation, but straight line winds will be a big problem when the storms arrive.

4/25 - 4:30pm - Storms in the West Coming This Way

A squall line of severe storms has formed this afternoon from Iowa down to Northern Texas. While the storms are severe, and even tornadic in Iowa, these are expected to weaken quite a bit before they reach us. The Balloon Glow tonight looks bleak due to the winds ahead of these storms.

The storms will give way to a semi-warm weekend and a cooler start to the week. Wednesday through Friday could harbor some severe weather as stated by the SPC. The GFS also verifies that statement with warm temperatures and precipitation forecast. This is the time of year when we really need to watch out for severe outbreaks like this. Things are fired up in the Plains, but those conditions could shift to this corridor by next week. We'll keep an eye on it.

4/10 -7:15pm - Quiet... Too Quiet...

Here's the situation. There's a nasty squall line getting fired up along the Mississippi River right now heading NE at about... oh, say... 70MPH!!! There is a tornado WATCH out for that corridor, but most of the tornadoes are on the Iowa part of the line. It's interesting because there are really two smaller lines right now, only miles apart. It seems as if they're canceling each other out in terms of energy, but once one dissipates then we're off to the races. I think that the southern part of the line is getting ready to hit the most unstable part of the country in just a couple hours. That ought to fire the storms up.

Another component is the tornadic activity in Iowa I mentioned. These storms are heading north pretty quickly, so I think those cells will die off pretty soon as they hit cooler, more stable air. Once that occurs, it is possible that the moisture feed could open up for our storms to use. Again, this is what is supposed to happen, not what actually will in most cases.

The SPC didn't issue a HIGH risk like many thought they would today. It seems that cloud cover ahead of the line of storms limited their punch. What affect the earlier cloud cover out west would have on our severe potential is not known.

If all goes according to plan, storms should roll in here just after midnight well within severe limits. Wind damage will be the primary problem, but a couple tornadoes aren't out of the question. Keep your weather radios on alert mode folks.