Stormtalk

Wednesday, 9 November 2011

Wall cloud north of Dayton, TX.

I was paying close attention to the weather yesterday (Tuesday, November 8), since I knew there was at least a chance for some supercellular-type thunderstorms across Southeast Texas. Having chased storms locally down here many times in the past, I certainly didn’t have very high expectations. But, I knew if a storm could hold its own and remain isolated that the wind shear was strong enough to support a tornado.

By noon the conditions were not exactly ideal with numerous scattered showers popping up well ahead of the dryline/cool front. I figured something would eventually fire and get its act together well west of Houston along or just ahead of the front, so I kept my attention focused there. Instead, an intense thunderstorm formed right over downtown Houston and slowly became better and better organized as it moved towards the northeast. With time, the storm began rotating. I abandoned my original ‘target’, told MaryLeigh we were leaving and headed out the door.

Wall cloud with developing funnel north of Dayton, TX.

Unfortunately, driving into downtown Houston on I-10 from Katy on a Monday afternoon isn’t exactly quick or easy (duh). And mother nature certainly wasn’t going to make it easy for us to catch this storm. Upon reaching the beltway, we saw a sign informing us of a major accident up ahead. We had to do some maneuvering, but were able to bypass the accident. This made it much more difficult to catch up to the storm. We reached the east side of Houston and shot northeast on highway 90.

Brief tornado near Dayton, TX.

By the time we’d driven a decent ways up highway 90, we approached the new storm that had fired just south of the original one. By this time storm structure was beginning to fall apart somewhat. But there was still some decent structure to be found. In fact, we drove through some heavy rain and saw a pretty well developed wall cloud just ahead. To our surprise, a very brief tornado touched down to our west! This is by far the weakest tornado and I’ve ever seen (and I realize I’m using the word tornado here rather loosely, but I did see a weak circulation on the ground).

We followed the storm through Dayton and north of Liberty. To our west at one point we saw a decent looking bowl funnel lowering from a new wall cloud. But the visibility was poor with the trees, bad contrast and rain beginning to wrap around the circulation. We continued north and caught back up with the updraft. Even in it’s weakened state, it was still re-forming a lowered base. And there were even a couple times when it looked like a funnel had breifly formed (see image below). I want to say this was just a scud bomb, but it formed within seconds right under the updraft and immediately dissipated…

Mysterious funnel/scud bomb a few miles north of Liberty, TX.

In the end it was a nice local chase. And considering we had to fight through Houston traffic and bypass an accident, I think this chase was pretty successful. For November, I’ll definitely take it.

- Jim

Friday, 21 October 2011

It’s been far too long since my last post. Most of that is due to the lack of anything interesting to discuss in the weather world. It is during this time of year that most storm chasers have had their eyes open for possible tornado setups across the Great Plains, at least for the past several weeks. It’s true that the typical peak in the tornado season is during the spring and early summer. But sometimes the autumn season offers some pretty spectacular tornado outbreaks as well, and is sometimes referred to as the second tornado season. It’s just that this year’s fall season seems to be a dud.

But I wouldn’t completely write it off just yet. Even though it’s a long shot, November can sometimes bring tornadoes to some pretty unlikely places. On November 12, 2005, Iowa was hit with thirteen confirmed tornadoes. This made it the largest tornado outbreak in November for Iowa. I chased the tornado that hit Gilbert, Iowa on this day. Below is a clip of some of the footage I shot (part 2 of 3).

Speaking of big November tornado outbreaks, there was another that occurred back on November 10, 2002. But this outbreak occurred over the Southeastern U.S. and Ohio! Eighty-three tornadoes hit 17 states between November 9th and 11th. Some of the most significant occurred on November 10 which included a F4 tornado that hit Van Wert, Ohio. A link to a video of that tornado I found on youtube is listed below. (This is not my footage).

 
http://www.youtube.com/watch?v=-tHc817UlEA

Since there are no tornado setups to discuss and there has not been any recent tornado footage in the U.S. to show (at least that I’m aware of), I thought I’d share a link to some impressive tornado footage from South Africa. On October 3rd, this tornado was captured on video near Dudza, South Africa. It’s pretty amazing video and something I would expect to see in Kansas or Oklahoma in May…not in South Africa!

http://www.youtube.com/watch?v=18YxQ4YYAkY&feature=related

Until next time…hopefully sooner than later…
 

Jim

Thursday, 25 August 2011: 11:00 p.m. CDT

Hurricane Irene track forecast valid 11:00 p.m. EDT.

Well, it’s finally come down to this: Hurricane Irene stands a high probability of having significant impacts on not only the Outer Banks of North Carolina, but much of the Mid Atlantic and Northeast coastline. Irene is a large storm, with maximum sustained winds of 115 mph. Hurricane force winds extend seventy miles to the northeast of the eye, and 50 miles to the northwest. That means even though the eye may only be skirting parallel to the Mid Atlantic coast this weekend, hurricane force winds will be felt well inland all along the Mid Atlantic and Northeast.

Irene’s minimum central pressure has dropped to 942mb, but that still hasn’t translated to an increase in maximum sustained winds. The lack of immediate wind increase may be the result of an eyewall replacement cycle. But Irene is expected to strengthen over the next 12 to 24 hours.

Hurricane Irene is growing in size and is not only likely to cause widespread power outages and damage across the East coast, but is also going to bring a damaging storm surge. Her winds are forecast to increase to 125 mph as she approaches the Outer Banks of Norther Carolina (If you live there you need to be evacuating right now!). Then wind shear is expected to increase this weekend, causing a slow but gradual weakening. But don’t let that make you drop your guard — Irene is a large storm. Hurricane force winds will likely extend at least fifty miles or more to the west and north of the eye this weekend. That is enough to cause widespread power outages. I think it’s safe to say Irene is going to have lasting impacts all across the Mid Atlantic and Northeast.

This entire situation is reminiscent of Hurricane Ike (for me I mean, not in storm comparison, although Ike was also very large) because Ike hit Galveston/Houston not long after I had moved from Houston to Connecticut! Now, having recently moved back to Houston, I find myself staring at yet another very large, intimidating hurricane heading to my previous home. Maybe the big storms wait until I leave to hit, who knows. It’s for the best though. After 60+ inches of snow this winter, my apartment in Connecticut had more water leak problems through the walls and roof than I’d like to get into. Follow that with a hurricane bringing flooding rains (see image below) and I think that it’s better I’m not there. But the weather enthusiast part of me is still a little jealous!

’till next time,

- Jim

Visible satellite image of Hurricane Irene valid August 24 as she approached the Bahamas.

Infrared satellite image of Hurricane Irene valid the evening of August 25, 2011.

Forecast precipitation in inches for the duration of Hurricane Irene.

Wednesday, 24 August 2011: Early a.m.

 
Hurricane Irene forms a well defined eye as she approaches the Bahamas…

Infrared satellite image of Hurricane Irene valid 0415 UTC August 24, 2011.

Hurricane Irene continues on a west-northwest heading towards the Bahamas, and is expected to turn more towards the northwest within the next twenty four hours. In the image above you can clearly see a well defined eye, and as a result Irene’s central pressure has dropped to 969 mb. However, this has not yet resulted in an increase in maximum sustained winds. Winds have actually decreased to 90 mph due to dry air to the west and some lingering 10-15 knot wind shear. But I think it’s safe to say that given the well defined eye feature and upper level outflow pattern that Irene will soon strengthen. At least that’s what the official forecast says, calling for Irene to reach maximum sustained winds of 125 mph in 48 hours! (That would make Irene a strong Category 3 Hurricane).

Large infrared view of Hurricane Irene valid August 24 early a.m. CDT.

The track forecast has shifted away from much of the Southeaster U.S coastline. As seen from the official NHC track forecast (below), Irene is expected to make landfall over the outer banks of North Carolina followed by a trip up the Northeast coast. But residents all across North Carolina should certainly still pay close attention to Hurricane Irene given the inherent track forecast errors beyond three days.

Track forecast for Hurricanen Irene valid 11p.m. EDT August 23, 2011.

This trend to the east in the forecast is due to computer models shifting further east (see below). As stated in the previous post, Irene’s track will depend significantly on the strength of a trough (or troughs) moving through the Northeastern U.S. later this week. Computer models now have a better handle of these troughs and indicate they will be a bit stronger than previously suggested. As a result, most guidance — including the tropical model suite– suggests Irene will pass over the outer banks of North Carolina or miss them to the east. I think both scenarios are possible, but honestly would place a higher probability on the outer banks being hit.

Tropical model tracks for Hurricane Irene valid 00z August 24, 2011.

One of the more significant model trends over the past 24 hours is seen in the GFDL tropical model. On the previous post I showed how the GFDL was forecasting Hurricane Irene to make landfall over south Florida near Miami. Well, the 18z August 23 run of the GFDL (see below) has Hurricane Irene making landfall over eastern North Carolina, not far from the outer banks! The HWRF tropical model shifted east too. It now has Irene missing the outer banks to the east. So, it’s going to be interesting to see how close of a call this actually turns out to be with this storm. Based on the data at hand it seems to me that the outer banks stands a higher probability of being hit vs. a miss to the east. But it’s still too early to be completely locked into a landfall forecast….

18z August 23 GFDL model for Hurricane Irene, showing landfall over eastern North Carolina on the evening of Sunday, August 28, 2011.

In any case Hurricane Irene should be moving into a weaker wind shear environment soon. As daylight hours move in upon this storm, I imagine some amazing visible satellite images will become available, eliminating an amazing eye structure and outflow pattern.

That’s all for now. Thanks for reading.

- Jim

Monday, August 22, 2011

Track forecast for Hurricane Irene valid 8p.m. CDT August 22, 2011.

Hurricane Irene has moved north of the mountainous island of Hispaniola, which has been the key in her strengthening into a hurricane. Maximum sustained winds are 100 mph, making Irene a Category Two Hurricane. Irene is expected to continue moving generally west-northwest for the next couple days and strengthen as she remains over warm waters and wind shear slowly weakens over the next few days.

By mid-week an upper level trough moving through the Northeastern U.S. will cause a weakness in the ridge centered over the Atlantic (which is currently steering Irene), and cause Irene to turn more towards the northwest and over the central Bahamas. Then later in the week another trough is expected to move through the Northeastern U.S., but computer models do not agree on the strength of this trough. Thus, they disagree on how much of an impact it will have on the track of Irene late this week into the weekend.

Tropical model tracks for Hurricane Irene valid 00z August 23, 2011.

For now, the National Hurricane Center has Irene making landfall on Saturday near the South Carolina/North Carolina border. But uncertainty is pretty high on what the actual impacts will be along the entire Southeastern U.S. coastline. There are many tropical models suggesting Irene may begin to curve towards the north-northeast as she approaches the Carolinas, implying she may only clip the outer banks of North Carolina. Then again the European model — which tends to be quite a reliable model — has Irene making landfall along the border of the Carolinas. Additionally, the GFDL tropical model insists upon Irene making landfall just north of Miami, FL!

August 22 18z GFDL model for Hurricane Irene valid Friday morning, August 26.

It’s far too soon to make any definitive landfall predictions at this time. But it seems pretty likely Irene will be the first major hurricane of the season to threaten the Southeast coast. All residents along the east coast of Florida, South Carolina and North Carolina should closely monitor Hurricane Irene. For updated forecast tracks on Hurricane Irene, please visit the National Hurricane Center’s Website. As far as chasing Irene, Stormagsm team members are getting ready for possibly the first hurricane chase of the season!

- Jim

Thursday, 14 July 2011

Visible satellite image of Typhoon 08W around 8 p.m. EDT on July 13, 2011.

As expected atmospheric conditions have improved and Tropical Storm 08W strengthened into a Typhoon yesterday. As of 00z July 14 (8 p.m. EDT July 13), Typhoon 08W (MA-ON) had maximum sustained winds of 90 knots (105 mph), making it a Category 2 Typhoon.

From the visible satellite image above, you can see an eye has formed in the center of the typhoon. The storm is really getting its act together as a result of warm sea surface temperatures and a ridge of high pressure in place. Both are excellent conditions for brewing a strong typhoon (or “hurricane” if we were talking about an Atlantic Ocean storm). Also evident in the image above is one very well defined outflow band which expands in a semi-circle across most of the northern half of the typhoon, well outside of the center. This banding feature is indicative of a ridge of high pressure aloft as well as increasing organization of the typhoon. Typically, when an outflow band is this well structured the typhoon is rapidly strengthening, or is organizing in a way that will soon lead to rapid intensification.

Based on the favorable oceanic and atmospheric conditions as well as the visible satellite clues, it’s no surprise that the Joint Typhoon Warning Center is forecasting Typhoon 08W to strengthen over the next 24 hours. In fact they are forecasting some rapid strengthening over the next 36 to 72 hours and expect Typhoon 08W to become a strong Category 4 Typhoon by the weekend. As the typhoon curves northwest towards Japan on Monday and Tuesday (July 18/19), they are forecasting some weakening due to increased wind shear. But from their intensity forecast and their discussion, it looks like they believe the typhoon may only weaken to a weak Category 3 typhoon, with 100 knot (115 mph) maximum sustained winds as it comes very close to or has a direct impact on Japan mid next week.

Track forecast for Typhoon 08W created at 8 p.m. EDT July 13, 2011.

Residents in Japan — especially southern Japan — should monitor this typhoon closely over the next several days.

- Jim

Tuesday, 12 July 2011

Infrared satellite image of Tropical Storm 08W at 7:32 EDT on July 12, 2011

 
Even though the Atlantic hurricane season is quiet right now, that doesn’t mean the tropics all across the globe are quiet. Today, Tropical Storm 08W formed over the western Pacific Ocean. Water temperatures are warm and wind shear is weak. Other atmospheric conditions are expected to be favorable for strengthening over the next several days as the storm moves west-northwest across the western Pacific. As a result, the Joint Typhoon Warning Center is forecasting maximum sustained winds to reach 95 knots (around 110 mph) this weekend as the storm begins to turn more towards the northwest in the general direction of Japan. That intensity would be considered a strong Category 2 Hurricane on the Saffir-Simpson scale if this storm was located in the Atlantic Ocean.

Computer models are indicating this storm will turn northward to very close to the coast of Japan early next week. How close the storm comes to Japan will depend on the strength and timing of a trough moving out of eastern China this weekend. At any rate this storm is something that residents in Japan should watch closely.

 
- Jim

Satellite image from July 12, 2011 of eastern Asia and the western Pacific.

Track forecast for Tropical Storm 08W valid July 12 from the Joint Typhoon Warning Center

Intensity forecast from the Joint Typhoon Warning Center for Tropical Storm 08W.

Monday, 11 July 2011

The build up and anticipation of an upcoming storm chasing season usually inspires numerous blog posts by chasers (including myself), offering a wide variety of topics. Then throughout the months of March, April, May and even parts of June pictures and videos of supercells and tornadoes can be found all over the internet. Websites like Facebook, YouTube, Stormtrack and various other social media sites become flooded with amazing photos and videos of tornadoes from hundreds of storm chasers across the country.

With this brings plenty of colorful topics for a storm chasing blog to choose from and expand upon. Then when the chaser heads out to the Plains for his or her own storm chasing vacation, the chaser is able to share the experience with his or her blog readers. Unfortunately, that time has passed us by for the year. The hot summer temperatures have been making a mark over much of the southern and central Plains for weeks now. Supercell and tornado opportunities still exist, but much further north across the Dakotas with a decreasing frequency as we head deeper into summer. While some storm chasers have the time to venture out and continue chasing throughout the summer months, this chaser does not.

As a result, many weather enthusiasts begin switching gears from supercells and tornadoes to tropical storms and hurricanes. After all, we are approaching mid July and are now only about a month away from the beginning of the peak Atlantic hurricane season. As we wait for the meat of the season to arrive, we can look across the Pacific for storms as well.

But alas we are well past the peak of the storm chasing season across the Great Plains of the U.S. For many storm chasers it’s pretty tough to accept the fact that the season is over, and another year separates them from the next chase. And while there is always the chance for a random spot chase here or there depending on the weather pattern, where you live, your financial situation, your job and your family life (lots of potential obstacles!), the point is the next time you can chase for several days or weeks without interruption is probably the spring of 2012. So maybe the only point of this post — if any — is to bring to the surface the reality that faces most storm chasers right now, and that’s the post chase season redux. If you don’t fit into this stereotype, then you are a member of the elite few and the envy of many chasers! I require you to share your secrets in the comments section.

- Jim

Monday, 6 June 2011: early a.m.

With the exception of some rain wrapped and brief tornadoes in Kansas on June 1, and of course the devastating tornadoes that occurred in Massachusetts that same day, the Great Plains have been quiet as far as supercells and tornadoes are concerned for about the past ten days. The culprit is a massive heat ridge that has brought high temperatures to the upper 90s and even 100s from Texas north into Oklahoma and Kansas, eastward to much of the deep South and parts of the Midwest. But, it looks like the severe storm and tornado activity is going to pick back up again beginning today (Monday), extending through the weekend.

The first setup is over the southeastern third of Montana today (Monday). I know that’s way up there (pretty close to Canada even!) where not only are there not many roads, but the terrain does become a bit hilly. I’ve chased in the southeastern portion of the state (the area I’m expecting storms), and I can tell you that even though there are gently rolling hills over this high terrain, it’s amazingly beautiful and you can really see as far if not further than you could say in the flat state of Kansas. The reason is because when you reach the top of one of the hills you are often overlooking a flatter region of the state, giving you an amazing vantage point.

00z June 6 WRF forecast valid 00z June 7 showing 850mb winds and pressures (7 p.m. CDT).

Anyways, strong southeasterly to easterly winds from the surface to 850mb (upslope flow) will cause enough gradual lift due to the orography to initiate storms by the late afternoon near the Billings area. The approach of a 500mb trough will also aid in the development of storms. But it won’t arrive until later in the evening, so upslope flow will probably do most of the work. At any rate, surface dewpoints in the lower to even mid 60s are expected to advect into the area by late in the afternoon, providing more than sufficient low level moisture fore severe storms. Wind shear profiles will also be great for supercells capable of very large hail.

00z June 6 WRF valid 06z June 7 (midnight CDT), showing a very intense 850mb jet over southeastern Montana.

As the upper air system from the west moves into the area near or just after dark, the 850mb jet will crank into high gear out of the east-southeast. I think the combination of the shear dramatically increasing after 7 p.m. CDT, the increased large scale dynamical forcing from the upper air system, combined with supercells moving further east into the lower plains with deeper, low level moisture will result into supercells becoming much more likely to produce tornadoes near and just after dark.

All in all, this is a pretty good setup for supercells, some tornadic, over Montana. The setup could be a little better considering the timing of the shortwave, but I’ve definitely seen much worse. I suppose I would be much more enthusiastic if the whole upper system itself would eject east a bit faster. But even so I think there could be a decent tornado or two in Montana today. Unfortunately, one or more may be after dark.

The setup for Tuesday shifts much further east into central and northern Minnesota. There a surface low, dryline and warm front will develop as the leading edge of the Montana system will be ejecting eastward. The CAP will be enormously strong all across the northern plains due to very warm mid level temperatures. But the combination of deep low level moisture convergence along the warm front/dryline aided with at least some dynamical forcing should provide for thunderstorm initiation across central/north central Minnesota by the early evening hours. The deep layer shear will support supercells. In addition, the backed 850mb winds at 30 knots will likely allow for some tornadoes to occur.

Next, we head southwest to Colorado for Wednesday’s most likely area for supercells and tornadoes. At 250mb, a strong belt of 50 to 65 knot southwesterly winds will be present by the afternoon and evening hours across much of Colorado. This will provide good ventilation for supercells that develop from upslope flow over the lee of the Rockies later in the afternoon. At 850mb, modest 20 to 25 knot winds out of the east to southeast will be present, providing some low level shear for supercells, but mainly large scale lift from upslope flow. The more important feature IMO is the surface low that develops in the afternoon over Denver and deepens in the evening. To me this looks like a rather classic ‘Denver Cyclone’ setup, given it’s occurring just after a weak frontal passage.

00z 6 June WRF surface pressure and temperatures valid 00z Thur June 9. Notice the surface low over Denver...this appears like a 'Denver Cyclone' type setup.

The main limiting factor for this setup is low level moisture. In wake of the frontal passage, only mid 40s to 50 degree dewpoints will be present across the northeastern half of Colorado by the early evening hours. This may not be adequate enough for tornadic supercells as the storm bases may be rather high. However, if lower 50s dewpoints can return by the early evening hours, then I think this could be quite a setup for tornadic supercells across the Denver region extending eastward later in the afternoon/evening.

00z June 6 WRF valid 00z June 9, showing surface dewpoints. Notice dewpoints only in the mid 40s to near 50 degrees F are expected across Colorado.

Then Thursday and Friday the supercell and tornado risk will extend over both Colorado and the southern/central Plains as another shortwave moves in from the west. Both days will feature a decent 850mb jet across parts of western/central Kansas into western Oklahoma and the panhandles. The CAP may be too strong further south, so it’ll be interesting to see what areas end up being the place to chase. By Saturday there will remain ample moisture, instability and shear for supercells across Kansas.

So after a relatively quiet period of time over the Great Plains I do think things will be picking up this week. Good luck to chasers out there and be safe!

- Jim

Sunday, 29 May 2011

Below: Arial photo of what’s left of the Walmart I was in just before the tornado hit in Joplin, Missouri.

Walmart on 20th St. and highway 71 in Joplin (the one I ran into). Photo courtesy AP.

Over the past week, it seems like all I see and hear in the media and even on Facebook is more tragic news about the Joplin, Missouri tornado. I can’t get the event out of my mind, so I thought I’d recap some parts of the chase day here on my blog.

The single most horrible thing that occurred that day was when I ran through the Walmart at 20th st. and highway 71 in Joplin. MaryLeigh and I were in a frenzy trying to locate a topographic map of Missouri, in an attempt to both 1)escape the deadly wedge tornado, and 2)maybe have a chance at getting into a position to view it before diving south. Anyways, when I parked the car in the Walmart parking lot, all we could see to our northwest was a black sky with a lowered base disappearing into the rain (apparently, THAT was the tornado). At the time, we actually didn’t know for sure that there was a tornado. But I had a very, very strong suspicion that there was a wedge approaching. In fact, I was nearly 100% sure, and quite frankly, a bit scared. NOTHING is worse than storm chasing through a city when a major, rain wrapped tornado is on the ground. Any storm chaser would agree that is a very, very dangerous situation. Period.

I told MaryLeigh I would run into the store just for a minute (literally) and grab a map if they had one. I ran as fast as I could, passing by families that were leisurely walking into Walmart to shop. The tornado sirens were blaring, so I’m not really sure why anyone would be so lackadaisical about the current severe weather situation! I didn’t see any maps at the front of the store, but there were three employees talking in a frenzy right by me. So I asked, and only after asking repeatedly several times did the employee finally mumble an answer…saying they were located in the back of the store. The employee was clearly aware of the tornado warning/siren, and was quite literally about to freak out, trying to hold her own composure. I felt really, really bad at that moment, because I realized if a tornado did strike there was nothing I could do to save anyone. I had to focus on mine and MaryLeigh’s lives. Every second mattered, and I figured you would have to be underground to survive whatever was coming (given the conditions).

I RAN to the back of the store, didn’t see anything resembling a map section, then RAN as fast as I could to the front of the store and out. I passed by several families calming shopping, as if nothing was going on. For the life of me I wish I could have told all of them to get underground or something, but there was simply no time for any of that. I knew every second counted. I had to get back to the car, to MaryLeigh, and get south immediately. I’ve never had such a sense of urgency ever in my life than I did in this moment.

Damage path of the Joplin, Missour EF5 tornado. The arrow points to the location of the Walmart where I went inside.

We left the parking lot, hauled it south, and continued on our journey out of there. But emotions began to run high as the day wore on when we found out that Joplin had been completely destroyed, and the Walmart I had run through was leveled. It’s quite likely most of the people I saw in that store are now deceased. The employee I spoke to briefly may no longer be alive.

Just moments after we left, that EF5 tornado destroyed everything. It’s quite a traumatizing thing to experience, and I truly hope I never experience anything like this again. As a meteorologist and a storm chaser, I have a strong passion for experiencing severe storms and tornadoes. But this was neither — it was an experience in human behavior right before a major tornado. This began as a typical storm chase, but ended as an escape from a deadly tornado, involving experiencing the seconds before human suffering. My thoughts go out to the people of Joplin, Missouri.

- Jim