Saturday, June 30, 2012

6/30 - 10pm - Wrapping Up the Storm Chasing Season

This storm chasing season is officially over for me as I'm back home in Louisville again. This week we went 2,930 miles through Colorado, Nebraska, South Dakota, North Dakota, Montana, and Wyoming. Our highlights of the week were a fantastic isolated severe storm with rotation near Lusk, Wyoming on Sunday and the tail-end of a line of storms that dropped a few funnel clouds near the Canadian border town of Scobey, Montana on Tuesday. All eight of us had a great time and I'm glad I was able to help forecast and explain to our guests what was happening with the weather during our chase.

The storm chasing we did this week brings my mileage for the season with Storm Chasing Adventure Tours to 11,313 miles. I've been from the Mexican border to the Canadian border this season and in the process I gained more perspective on just how huge the United States is. Over the next few weeks I'll be assembling a compilation of my best storm video from this season and I'll post it when I'm finished on here and on my website. All of my photos from the past four weeks of storm chasing are already up on my Flickr and Facebook albums, so click on over and flip through them!

Friday, June 29, 2012

6/29 - 10:15am CDT - The Chase Ends...

Today we're heading back to Denver as Tour 8 with Storm Chasing Adventure Tours ends. Right now we're making the seven hour journey from Valentine, Nebraska where we stayed last night. We had a storm about an hour south of Valentine yesterday that showed some promise, but it fell apart as it moved east. Tomorrow is when everyone departs and that's my cue to get on my plane back home to Louisville. It's been a great week with just about every day being a day with an active chase.

This is not one of those chase days unfortunately. With our required drive back to Denver we don't have time to chase any storms that are more than a few miles away from our route. There is a Slight Risk for storms today in Northeastern Nebraska stretching into South Dakota, but that's just too far out of the way for us. We may have a few run-of-the-mill storms along our route back to Colorado, but that's about it. I'll have a post tomorrow detailing our mileage and route from this week.

Thursday, June 28, 2012

6/28 - 11:30am MDT - Waking Up in Nebraska

After storms in Northeast Colorado yesterday became contaminated by storms coming off the Front Range, we decided to head east to be ready for today's chase. After waking up in Ogallala, Nebraska this morning we're rested up for a relatively leisurely day without too much driving since we're already pretty much in our target area for the day. The Storm Prediction Center has a general thunderstorm risk out for Western Nebraska, Northeast Colorado, and Northwest Kansas today with a 5% severe wind risk.

The focus today will be a cold front that's slowly moving through the region today. Winds around this frontal boundary may shift out of the east a little bit and that's where we'll position ourselves since the best shear will be where that happens. Dew points will be in the 60's across Central Nebraska this afternoon with slightly lower readings to the west. These surface winds, while weak, and the moisture should be more than enough to get some storms going.

Winds aloft are a little less certain since they may change throughout the day. Early on this morning winds at 500 mb (18,000 feet) were almost westerly across the western half of Nebraska, but already we've seen a shift to the southwest. While not terribly strong, the winds up there could have just enough punch to get storms to become severe. Small embedded shortwaves within the flow may enhance these winds a bit in some areas too. By 6pm MDT tonight the RAP model (right) still has these winds out of the southwest aloft, so that's some good news. The thinking at this point is that the shear won't be high enough to keep storms from merging together and being clustered, but we'll see how that plays out.

Follow me on Twitter and Facebook for constant updates during our chase!

Wednesday, June 27, 2012

6/27 - 10:40am MDT - On the Border

Yesterday's chase logged us a marathon 814 miles as we traveled from just north of Rapid City, South Dakota up to the Canadian border in Montana and then back down again to I-94 in Montana just west of Miles City. The good thing is that it was worth the drive because storms that formed in Sasketchewan had a tail-end just across the border in Montana. This tail end, referred to as "tail-end Charlie" by chasers, had quite a bit of rotation in it and put down quite a few finger funnels that were clearly in rotation. The dry winds from the west pushing this line of storms along were insane too, causing a nearly constant 50 mph crosswind for us as we drove northward from Glasgow, Montana. Our target area shifted considerably north and west during the day because temperatures in Eastern Montana and Western South Dakota got much warmer than expected and drove the best environment toward the border. As we suspected the best storms were in Canada across the border from us, but we can't go there since we're not equipped nor allowed to enter there. It was certainly an exciting day yesterday and we're happy we made the drive! I can now say that I've been to both the Mexican and Canadian borders this chase season.

Today we're diving southward toward the Northeast Colorado and Western Nebraska to catch some storms that a cold front moving down that way will generate. Surface winds may turn out of the east a little bit near and along the front, so it is possible that we'll get some upslope flow to aid storm genesis along with the front. Dew points will be near 50 degrees, which may sound low but is actually just fine for storms given the high elevation.

Upper-level winds around 18,000 feet (500 mb) will actually be quite favorable today because of a shortwave trough embedded in the overall disturbance moving through the northern part of the country and Canada. Winds at that level out of the southwest at around 35 kt are being forecast by the RAP model and that's not too bad given some of the past environments we've chased in this week. The main issue today will be the strong cappping we've dealt with all week due to warm air at the mid-levels, but surface heating should be enough to break the cap and form a few storms.

The Storm Prediction Center has issued only a general thunderstorm risk for our target area today, but it does include a 5% severe wind risk. We're still quite a few hours out from being in the area since we're still in Montana, but we should make good time and be there as storms begin to form.

The latest updates on our chase are available on my Twitter and Facebook accounts!


Tuesday, June 26, 2012

6/26 - 10:40am MDT - Another Day, Another State

Yesterday near the Black Hills of South Dakota we saw a few storms develop but they never got organized enough to be good for chasing. One storm in particular had some promise but it just couldn't get strong enough to leave the elevation of the Black Hills where its updraft was rooted. Today we're going north from the Black Hills and moving into North Dakota where there should be a threat for severe storms this afternoon. In particular, areas near and just west of Williston, North Dakota into extreme Eastern Montana appear to be under the greatest threat since a few isolated storms could produce hail, wind, and maybe even an isolated tornado. The Storm Prediction Center only has a general thunderstorm risk for this area but there's a 2% tornado risk included. You'll see the Slight Risk up there in Montana as well in the map to the right, but that area is very remote and the surface winds likely won't cooperate as well for storms like they will in North Dakota.

Winds aloft are forecast to be stronger in our target area today than they were yesterday in South Dakota since the upper-level disturbance over the northwestern part of the country will be moving east a little. When you couple these stronger southwesterly winds aloft with southeasterly winds at the surface that can create some shear for rotating storms. It's worth noting that the best surface winds could be in Canada just north of North Dakota and Montana since an area of low pressure will be spinning winds around from the east there. Since we can't go to Canada, that's obviously out. Dew points in North Dakota are downright soupy this morning and will likely continue to be that way through the afternoon. Having 70 degree dew points right on the Canadian border is something you don't see too often.

With all the warm air and moisture in place, instability will be plentiful for storms. I talked about the threat of isolated tornadoes today on the SPC's outlook and that may very well verify if the instability and shear come together. A great way to combine those two factors is to look at the Energy Helicity Index, which starts getting higher in an isolated spot in Western North Dakota according to the RAP Model. We'll see if it's enough to get some good storms going this afternoon and evening!

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

Monday, June 25, 2012

6/25 - 10:30am MDT - Great Faces. Great Places.

Today's blog post title is the South Dakota's state slogan. As you can probably gather by that, we're in South Dakota today! Southwesterly flow aloft at 500 mb (18,000 feet) will be present in the western half of South Dakota, northwest Nebraska, and Eastern Wyoming today as the general pattern we dealt with yesterday continues. While the winds aren't terribly strong, the RAP model is beginning to pick up on an area of enhanced speeds near 30-40 knots around parts of Western South Dakota and Northwestern Nebraska. If this enhanced area verifies there could be some better storms under it.

At the surface right now there are southeasterly winds across this area, but the more easterly of the wind vectors are favoring Western South Dakota right now. We'll see how this develops throughout the day as surface conditions continue to change. We'll want these more easterly wind vectors becuase they'll contribute to low-level wind shear that could possibly lead to rotating storms, should they form.

I say "should they form" because we're still dealing with some very warm temperatures aloft. These warm temperatures aloft, called "the cap", inhibit storm development because rising air parcels can't continue to rise buoyantly if the environmental air around them is warmer than they are. The good news here is that temperatures at the surface today will again be in the 90's to near or above 100 degrees. This will really heat up these surface air parcels so that they might shoot through the cap. All models I've looked at this morning have the cap breaking at some point in the early to mid afternoon, but where exactly this happens is still in question. The 14z RAP model has an interesting hole in the cap at around 4pm near Rapid City, but our current thinking is that the Black Hills near Rapid City will be a focus for storm development because they are a constant source of lift and thus a typical location for storm initiation.

To get some of the heating we'll need for storms to form today, we need to have a plentiful supply of sunshine. Right now we do have a layer of clouds over South Dakota that is inhibiting this right now, but western parts of the state are clearing out and it should hopefully leave us with blue skies later this morning. Storms should form sometime after 3pm this afternoon should things come together as forecast. The main threats will be wind and hail from any storm that forms, but we'll be on the lookout for some rotation in these storms as well. The Storm Prediction Center has a general thunderstorm risk for our target area today, but also mentions a 5% severe wind and hail risk.

Follow me on Twitter and Facebook for the latest updates this afternoon!

6/24 - 11:55pm MDT - An Unexpectedly Great Chase Today!

I can't say that I fully expected to see a great storm today. With all the intense surface heating and warm air aloft coupled with weak upper-level winds, the odds were against us. The great thing is that a storm did indeed form in this environment and it took advantage of every ounce of energy it was given from what it looked like. This storm split into a couple parts at one point and these parts were battling each other out for a while before merging back into one mean storm. This storm did have a few radar scans of rotation and we could certainly see it from the ground for a few minutes as a brief rotating wall cloud formed. A fleeting finger-like funnel danged down for a moment at the peak of the rotation, but it was gone by the time we all pointed it out and raised our cameras to capture it. Something that stuck in the back of my mind is what I posted on the Storm Chasing Adventure Tours Facebook page last night in an update:
Looks like we may be heading north from Denver in the morning! A few storms may try to develop during the afternoon and evening tomorrow where South Dakota, Nebraska, and Wyoming meet.
The intersection of South Dakota, Nebraska, and Wyoming is almost exactly where this storm formed today. Where the three white lines intersect to form a rotated "T" on the upper-right of the radar image to the left is where these state lines come together. My estimate of where we would end up was an educated guess based on data, but I really didn't expect it to come so incredibly close. The other thing about this storm is that it was the only severe storm west of the Mississippi River at the time we were chasing it during the late afternoon. Storms that developed to the south of us in Northeast Colorado just couldn't get strong because it was much too warm both at the surface and aloft.

Check out the video below to see the storm in action and then check out my Flickr or Facebook storm chasing albums for even more views of today's chase:

Tomorrow we'll be heading northward to the Dakotas or Wyoming. The Storm Prediction Center has a 5% risk for severe weather, but we'll be looking at all the data tomorrow morning to see how it all shapes up! Be sure to check back around noon tomorrow on the East Coast for a complete blog update with a discussion on where we're headed.

Sunday, June 24, 2012

6/24 - 10:35am MDT - The Chase Begins!

This morning we're heading toward Cheyenne, Wyoming from Denver as we continue to look at weather data coming in. Today's setup still looks marginal by most accounts, but there are a few small features that could cause a few isolated storms to go severe. For one, surface winds out of the east in Wyoming, Northeast Colorado, and Nebraska will generate upslope flow, which is the lift mechanism we need to get storms going.

These winds will also create some shear because they will be interacting with southwesterly winds at 500 mb (18,000 feet). The issue with this is that the faster winds at this level will be further north toward Rapid City, South Dakota instead of where the more favorable surface winds will be just to the south. In any case, the wind direction at 500 mb will be good enough to usher in the wind shear and maybe some drying of the air at that level to increase instability.

When you put the expected helicity (caused by wind shear) and the instability together for today, you get the Energy Helicity Index (EHI). According to the 14z RAP model, the EHI may try to ramp up a little bit in Northeast Colorado and it even breaks out a little bit of precipitation just west of there too. Surface heating is going to be massive since temperatures will be in the 90's and 100's in some places, so we're hoping this also helps overcome some of the warm temperatures aloft (the cap) so that isolated storms can develop. We're grasping for small features today since there isn't any one thing jumping out to get our attention, but so far it looks like a storm or two could fire on the elevation near Cheyenne. We'll also be watching an area closer to Rapid City, SD to see how things develop up that way.

Follow my continuous chase updates on my Twitter and Facebook accounts today!

6/23 - 11:30pm MDT - Who's Ready to Go North?

Our tour guests have been through orientation and now we're ready to set off for our northward journey tomorrow from Denver to the region where Wyoming, Nebraska, and South Dakota meet. This area will be on the northwestern side of the large ridge in the middle of the country and on the eastern side of the trough coming onshore from the Pacific. This means there will be southwesterly winds aloft, at 500 mb or 18,000 feet, to hopefully bring in some drier air so that instability will increase when it contrasts with the warm, moist air at the surface that will be rising into it. While weak in speed, the winds up there will also increase wind shear because they will be at odds with the easterly and southeasterly winds at the surface. This will increase helicity a little bit, which is a corkscrew-like rotation in the atmosphere that is good for fueling rotating thunderstorms.

Moisture shouldn't be too big of a deal since dewpoints will be in the 60's, but we'll be eying the potential for issues with the the cap, which is a warm layer of air above the surface that inhibits thunderstorm development. All the warm air in place over the central part of the country breeds strong capping since the warm air is in place at the mid levels, but the models are suggesting that this cap may be overcome tomorrow afternoon and lead to some isolated storms. At this point there is nothing that suggests any storm that forms will be anything past marginally severe, but the helicity that the NAM model is picking up on above is certainly worth keeping an eye on.

The Storm Prediction Center has a general thunderstorm risk out for our target area tomorrow with no chance for severe weather. Since storms will be pretty isolated and in a fairly unpopulated area, it may not be worth it for them to issue any sort of severe risk with a setup this marginal. We'll see how things have developed overnight when we set out in the morning though. A secondary low may try to form in western South Dakota tomorrow according to the NAM and that may influence our decision on where to go if it forms since the best winds will be just to the north of the low center. Hopefully we'll see some storms!

Follow me on Twitter and Facebook for the latest tomorrow!

Friday, June 22, 2012

6/22 - 10:30am - Storm Chasing: Part 2

Tomorrow morning I leave Louisville for Denver as I set out for one last week of chasing storms with Storm Chasing Adventure Tours this year. This will be a late-season chase, meaning that the threat for severe weather will be much further north than where it was during the peak of the season in May. Unfortunately it looks like the pattern will be a little dull until the middle part of next week due to a ridge of high pressure that will be in place over the middle part of the country. By Wednesday an upper-level low will finally move across Alberta and Saskatchewan, which will bring southwesterly wind flow and maybe even a secondary short-wave disturbance through the Dakotas, Wyoming, and even parts of Nebraska. Moisture looks a bit modest at this point, but it's way too far out to judge that properly since model accuracy is low this many days out.

During the chase next week I'll be posting daily blog updates here and real-time chase updates on my Twitter and Facebook accounts. Each morning I should be able to post a weather briefing as I did back in May so that you'll have the latest on where we'll be headed to and why. Hopefully we'll be able to find some good storms!

Tuesday, June 19, 2012

6/19 - 3:15pm - The Last Day of Spring

Tomorrow marks the first day of summer as the summer solstice occurs at 7:09pm EDT. The summer solstice put simply is the longest day of the year in the northern hemisphere because the north pole is tilted toward the sun. The sun will be directly overhead at 23.5 degrees north latitude or the Tropic of Cancer, located on a line that runs between Cuba and Florida. Meteorological summer, the three month period that meteorologists consider summertime in weather terms, started on June 1st with hurricane season.

I'll tell you that it's been pretty warm in Europe over the last couple of weeks. My family and I enjoyed a very nice trip around the Mediterranean Sea and traveled to Italy, Croatia, Turkey, Monaco, and Spain. I'm still a little jet-lagged from the marathon flight between Barcelona and Philadelphia we were on Sunday, but I'm slowly acclimating to Eastern Time again. Crazily enough, a tornado touched down in Venice, Italy last week well after we had left port on our ship. Thankfully there were no injuries, but some damage was done in a place that rarely sees tornadoes. Read more about what happened here.

The heat we had in Europe followed me home to Louisville (not meteorologically of course) and now we're experiencing quite a heat wave. High temperatures are expected to be at or above 90 degrees for most of the week here, but we may get a small break on Thursday night/Friday morning thanks to a cold front approaching the area. This thing may run out of steam just as it's nearing the Ohio River late on Thursday so rainfall chances could be slim with this.

If it continues to chug along further south than expcted we could have some storms around during this timeframe. Areas in Western Kentucky and Northwest Tennessee do need the rain, but unfortunately this won't be enough (if it happens at all) to assuage much of the drought in that region. The US Drought Monitor from the University of Nebraska-Lincoln has portions of this area under a moderate to severe drought. 

In just four days I'll be heading to Denver to join Storm Chasing Adventure Tours for one more week of storm chasing this year. It's been a whirlwind of a summer break for me so far with three weeks of storm chasing and two weeks of travel in Europe under my belt, but I'm definitely excited for another week of chasing! It looks like storms may fire up early to mid next week in the Dakotas, Nebraska, and Wyoming as an upper-level disturbance inches onshore from the Pacific. It's a bit far out for specifics at this point, but I think moisture and upper-level support during this time might be decent if this disturbance comes onshore in time. The limiting factor may be capping (warm air) aloft since temperatures may be a little high up there. It'll be interesting to see how this develops over the course of the week!

Be sure to follow me on Twitter and Facebook so that you'll be ready to receive my instant storm chasing updates next week!


Friday, June 1, 2012

6/1 - 9:15am - Going off the Grid

Starting this morning I will be on vacation for the next couple of weeks. I will likely not have internet access during this time so my blog and social media accounts will remain inactive until June 17th. As soon as I get back I'll be gearing up for another week of storm chasing that starts on June 23rd.

Here are a couple of weather tidbits going on today:

This is officially the first day of the Atlantic hurricane season. You wouldn't know it though because there have already been two named tropical storms Alberto and Beryl. No storms are going on in the Atlantic at this time and the forecast is for that to remain the same for at least the next couple of days.

There is a Slight Risk for severe weather over the Mid-Atlantic states today. A 10% tornado risk is in place from North Carolina to Maryland and there could be isolated supercell structures out that way during this afternoon's storms. A few high-based supercells may form in the Texas Panhandle this afternoon as well... hopefully my friends at Storm Chasing Adventure Tours can chase a few of these!