Stormtalk

Thursday, 19 April 2012

 

 

It’s difficult to know where to begin on a post like this, because it’s been five days since we saw the tornado, and I’m on day three of being back at work and into the swing of things again. My body still has not mentally or physically recovered from the drive to Kansas and back to Pittsburgh, PA. So you understand why this post is just now being made! But given the amount of driving coupled with little sleep and a tornado setup that underperformed during daylight hours, I think a post is warranted despite its tardiness.

MaryLeigh and I left Pittsburgh at 5a.m. on Friday, April 13 and drove straight to Derby, KS, arriving at 11:30pm that night. On the way to Kansas we picked up our friend Steve Barabas at the Kansas City airport to chase with us the following day. I had been watching the setup for April 14 all week and wondered daily whether or not it would be worth the loooong drive out to the plains and back. You see, since the setup fell on a Saturday I had (potentially) the unique opportunity to take off Friday and Monday from work to chase this setup. This would undoubtedly involve driving for hours on end and getting very little sleep over the course of nearly four days, but I believed it would be worth it if the setup actually looked like a historic tornado outbreak.

And wouldn’t you know it, by the time the morning WRF model came out on Thursday, April 12, the setup indeed looked like a massive tornado outbreak! All computer models were in excellent agreement, so I honestly had no reason to believe there were not going to be tornadoes. So upon requesting the time off work, getting odds and ends together and going to the store for necessary road trip supplies, MaryLeigh and I were prepared for the long drive to Kansas the next morning.

Right before we left Pittsburgh, I looked at the latest WRF and GFS models one last time before leaving. The setup looked even better and the Storm Prediction Center agreed. For the first time ever, or at least the only time I’ve ever seen this occur, the SPC issued a high risk on the morning of a Day 2 outlook. (See their outlook graphic below). The following quote is from their discussion and is something I’ve never seen them say on a Day 2 outlook:

“AFTER COLLABORATION WITH WFOS WICHITA…NORMAN…TOPEKA…TULSA AND DODGE CITY…A HIGH RISK WILL BE ISSUED DUE TO THE POTENTIAL FOR A HIGH-END LIFE THREATENING EVENT ACROSS THE SRN AND CNTRL PLAINS.”

 

 

So after about 20 hours of driving and a pit stop at the Kansas City Airport to pick up Steve, we arrived in Derby, KS at 11:30pm. I reviewed the latest data and models for the setup, and things honestly looked quite a bit different — in a bad way! Thunderstorms were forecast to fire along the dryline several different times from the morning throughout the afternoon from various convective models (WRF, HRRR, RUC), so uncertainty in the forecast rose significantly. Mind you I was looking over this data around 1:30a.m. after driving 20 hours straight and I really wanted to get at least a few hours of sleep! But all I had to look forward to was 5-6 hours of tossing and turning being worried about the setup. I did get some sleep — enough for the day — but I wanted so much more. (Hell, I want more sleep right now)

People say that sometimes things look better in the light of day after a good night of sleep. Well I didn’t get the good sleep, but upon reviewing the latest weather data at 8a.m. on Saturday, April 14, things were looking up. None of the thunderstorms the models were forecasting had formed yet, so there was reason to be suspicious of their solution during the daytime. It still appeared supercells would form by 1pm, but enough instability would develop and tornadoes seemed likely.

We drove west to Pratt and before much time had passed, supercells formed along the dryline over the eastern Texas panhandle and Oklahoma panhandles. We waited until the best looking storm got organized and showed good rotation before heading further west to view it. But it the storm produced a quick tornado before we got to it southwest of Greensburg, KS. In fact by the time we arrived on highway 400 west of Greensburg near Mulliville, KS the storm was actually falling apart. Something just wasn’t right. I had expected to see a large tornado on the ground, but instead was greeted with crappy looking outflow, scud and a convective mess.

I decided we should just go east and get out ahead of the storms and wait for the storms that were currently intensifying to our southwest near the KS/OK border to get their act together. But the closest storm (southwest of Pratt) later did the same thing by dissipating, only it never (to my knowledge) produced a tornado…may not have even had a funnel for all I know. I was worried about falling behind the storms (they were moving northeast at 55mph), so I continued to drive east on highway 400.

In the car frustration increased as I kept checking the radar and the warnings. No storms in Kansas or Oklahoma had any confirmed tornadoes, and it was after 4pm. To make matters worse, the radar signatures were not impressive – both on storm relative velocity and echo tops. Tops were struggling to surpass 40/45K feet. It was becoming obvious that the CAP was stronger than forecast and was causing the updrafts to struggle. No wonder this “Outbreak” wasn’t happening (yet). I seemed that maybe we should be further north where the upper air support was located.

I decided it would be best to keep up with our storm (which looked like crap) and drive north on highway 17 to Hutchinson. For a little while our storm (located to out west several miles away) developed a massive beavers tail and that got our hopes up. Then I looked at the radar updates and the storm was clearly dying! The NWS issued a tornado warning, but I laughed because I knew it was over for this one. At that time the supercell well northwest of Hutchinson began rotating like crazy and a large tornado was immediately reported! That’s when I decided we had to attempt catching up with that storm. The problem was it was moving northeast at 50mph. But I knew it was highly possible the storm would slow down a lot since it just began producing tornadoes.

We took highway 61 northeast through Hutchinson and unfortunately were caught in construction going 45mph for a long time. This destroyed our chances of catching the large tornado currently on the ground. However, upon reaching I-135 on the east side of McPherson, the radar image updated and I saw that the supercell had slowed down quite a bit, and was still located west of I-135 just southwest of Salina! We definitely had a chance to catch up up to it if we navigated effectively.

Hope, determination, quick radar interpretation and fast map navigation came to the rescue. After taking I-135 north for several miles, we got off at an exit and took small farm roads east and north to Gypsum, KS. It was about that time that the tornado first touched down. But being several miles south of it, we still had to fight to even remain in view of the tornado.

 

 

 

 

Unfortunately, we were simply too far behind the storm to remain in good, consistent view of the tornado. For a couple minutes a hill and some trees blocked our view as we continued driving north and then east to keep up with the storm itself. From seeing that the rear flank downdraft was really slow to occlude the mesocyclone, I knew the tornado would be on the ground for several minutes (and it was). So I tried to get us into better position by continuing east a few miles and then north, instead of stopping initially with a view of the very photogenic stovepipe and capturing really good video and stills. Unfortunately, most of the tornado life-cycle was during a rope-out stage, and was hard to see initially due to repositioning and poor contrast.

 

Upon reaching I-70 I captured a shot of the roping-out tornado (below). We could have easily driven north on a farm road and gotten into a better view for this, but it would have ruined our chances of getting much closer to the next tornado (assuming at the time their would be one, which there was not). Plus, I honestly didn’t know how much longer this rope would last! And that’s the gamble I made with this storm. I had no idea it wouldn’t produce another tornado during the daytime hours, nor did I know the stovepipe stage would only last for small portion of the tornado life. But it was a great looking supercell moving into a great environment, so go figure.

 

 

I felt we were very fortunate to see this tornado after a frustrating first part of the chase and being forced to drop storms. The setup didn’t pan out like I thought it would during the daytime hours, so I consider us lucky to have seen a tornado. On the drive back to Derby, we stopped just off I-135 about 10-15 miles southeast of Lindsborg (north of McPherson) around 10pm or so. We watched a supercell with a confirmed tornado pass several miles to our northwest. The supercell exhibited strobe-light lightning in a way I’m not sure I’ve ever witnessed in 12+ years of storm chasing! The inflow winds were so powerful it almost knocked me over at one point! We witnessed two power flashes as the supercell passed to our northwest. It was quite spectacular.

At the same time a tornado missed our friends house in Derby, KS (where we were staying the night) by only two miles! It was from the storm that developed over far northwest Oklahoma and began producing tornadoes within an hour of us dropping our dying storm and hauling it north. So when we arrived back in Derby late that night, we were lucky to get to their house having to maneuver around debris and tons of EM vehicles. We had no power at the house so it was extremely warm inside. And leaving he windows open was almost fruitless because a squall line was approaching and it was also very windy. But sleep eventually found its way to each of us out of pure exhaustion.

MaryLeigh, Steve and I left Derby Sunday around lunch time on Sunday. We drove to eastern Oklahoma so he could meet up with a friend. MaryLeigh and I were pretty happy when we finally arrived back in Pittsburgh later the following day.

Thanks for reading this novel. There will (hopefully) be to come in the next three weeks as the weather pattern gears up again for more tornadoes across the Great Plains in late April and early May!

- Jim

Tuesday, 3 April 2012

 

 

Two damaging tornadoes moved through the Dallas/Fort Worth area today. For several minutes both tornadoes were on the ground at the same time. Given the proximity the Dallas/Lancaster storm was to a TV station’s tower cam, I had the unique opportunity to view this tornado live for several minutes on my computer.

The image above is a screen capture of the tornado from the live feed.

 

 

While I viewed the live feed of the destructive tornado that moved through the south and east side of Dallas, another supercell was producing a large tornado on the south and east side of Fort Worth, moving through the Arlington area. No live feed was available, but the news did pan to a quick, previously recorded shot of that tornado, which appeared from a distance to be a large cone tornado. You can see the two well defined supercells in the Dallas and Fort Worth areas on the radar image above. These cells developed ahead of a line of thunderstorms.

 

The image above gives you a good view of the tornado from a distance. Again, seeing a tornado live on TV or through a live feed as it moves through a major metropolitan area is unreal. I watched the feed as the tornado moved through the southeast side of Dallas and ripped up trailers, structures and semi-trucks that were parked at a truck stop. Large pieces of debris were being thrown into the air.

 

 

As I come to the end of this write-up, tornado warned supercells continue to move through the Dallas Fort Worth area. I’m afraid that quite extensive damage may be waiting for assessment once the day is over.

Days like today remind me that we are living in a new era of storm chasing/viewing/spotting. The era of live feeds. This has been around for a few years now, and today isn’t even the best example since the feed was from a TV tower cam! However, more and more storm chasers are taking advantage of broadband cell phone internet access on the road and providing live tornado feeds.

Today just reminds me that the old days of storm chasing are dead and gone…and the new era of live photo and video updates on Facebook, Twitter, and storm chaser websites is the new standard. I guess I bring up this topic because things were so much different twelve years ago when I was first getting started in storm chasing. I’m part of the previous generation of storm chasers that had to rely on computer internet access at public libraries, nowcasters via cell phone, my eyes and instinct to find tornadoes. Well, now I can view radar images at will while chasing at nearly any time I wish, and access to data is simply amazing while chasing. I guess days like today just make you stop and think…

Thanks for reading.

 

Jim

Wednesday, 28 March 2012

 

 

I’ve been beyond busy with life and work recently and just haven’t had the time or energy to reflect on the historic March 2, 2012 Henryville, Indiana tornado day. Finally, push came to shove and I’m pretty much forcing myself to write this post before too much time has passed. Plus this blog needs some attention from yours truly.

As luck would have it I had the opportunity to chase with my good friend and long time chase partner Simon Brewer. I had not chased with him or our other Stormgasm original Tom Santillo since (ironically) last March! It was really nice to catch up with him. But not only that, it was great being able to focus on shooting steady, quality video when it mattered (that isn’t normally possible when you chase solo or with a non-veteran chaser).

We both knew the conditions on this day would simply be outstanding for violent tornadoes, and I knew if things came together just right it would likely be a historic day (of course we chasers say that more times than not, but usually something makes the setup less than perfect). As you can see from the photos, things came together just right this time.

 
 

Below is a clip of the video I shot of the Henryville, Indiana tornado. This is in a much lower quality than the original video which was recorded in HD, and of course the original video is much longer in duration.

 

 

 
We saw the first storms form in southwestern Illinois which quickly became supercells. At that time we were in east central Indiana expecting to either intercept the ‘main’ cell, or a new cell that might form out ahead of it somewhere in south central Indiana. A new cell did form ahead of the main cell and when it took over and became the dominant cell, I knew it was going to produce a violent (and likely deadly) tornado. I knew this because of the incredible CAPE and shear environment the supercell was moving towards. A tornado (likely violent) was nearly a guarantee given all the conditions that were present. When I came to that realization -quite honestly- I felt sick to my stomach.

 
It was while we were sitting at the Henryville, Indiana exit off I-65 looking at the latest radar image. We didn’t have much time to make a decision since the supercell was moving northeast so quickly. We were trying to decide where to sit and wait for the storm to come into view (at the time we were thinking we’d probably see a big, violent tornado tornado emerge).

I can’t remember exactly when we received confirmation from the storm reports/tornado warning that a tornado was actually on the ground from this storm (we couldn’t see a thing yet from our vantage point). I do remember seeing the radar image, which featured a debris ball and a maxed out SRV signature (means a BIG tornado is very likely on the ground). That’s about the time when I realized people were in a lot of danger – for their own lives. When violent tornadoes move rapidly through hilly terrain it becomes an extremely dangerous situation, life threatening situation.
 

 
We ended up deciding to head down to the next exit, south of Henryville. We parked the car at a truck stop that was situated at the top of a small hill, which offered the only vantage point in the area. I stood on the edge of the woods on mud, brush, broken tree branches and all, trying to get a view of the storm. Within a couple minutes the tornado was in our view, some 20 miles to our southwest!

This tornado ended up being in our view for several minutes, and is one of the most photogenic and intense tornadoes I’ve ever seen. After the tornado crossed I-65 another supercell was approaching from the southwest. The tornado that storm produced was rain-wrapped. Luckily it did not pass directly over our location, but the storm did drop large hail.
 

 

 

 

 

The main tornado (seen in all the photos posted) which hit Henryville, Indiana was rated EF4. It caused such extensive damage that all roads except I-65 south were blocked from debris. We actually sat at the same exit from which we viewed the tornado for over 30 minutes trying to figure out how to get home! Finally, we decided to go south on I-65 and loop around the northwest side of Louisville. In doing so we ended up driving north on state highway 135 north of Palmyra. That’s where we inevitably ran into the damage path from the early stages of the Henryville tornado. The tornado had managed to scour massive chunks of asphalt from the road and toss them tens of meters into a field!

Simon and I were simply astonished at the damage. In fact as we documented what we were seeing, people began pulling over and getting out of their cars to view the damage. It was just incredible to see that a tornado had ripped such large, enormously heavy junks of asphalt and thrown them such a distance. This damage is on the same or even greater level of severity as what I saw in Franklin Kansas on May 4, 2003, from a tornado that was rated a high-end F4. If anything this asphalt damage is even more severe, and that speaks volumes, because I don’t think the Henryville tornado was at its strongest when it crossed this state highway…

 

- Jim

Monday, 20 February 2012

 

Conditions will be coming together late this afternoon and early this evening to produce low topped supercells across central/eastern Oklahoma and southern Kansas. This might come as a surprise to some people considering today’s date. But enough cold air at the mid levels and a marginal amount of low level moisture will come together to bring conditions favorable for a couple tornadoes.

The main limiting factor truly is the surface dewpoints, which will struggle to reach the lower 50s by the early evening hours across central Oklahoma. This will limit overall instability as CAPE will likely only be in the 200-500j/kg range. While this is sufficient for severe storms and even supercells, it suggests short lived low level mesocyclones, i.e. brief tornadoes as storms fight for low level CAPE.

From a storm chasing perspective these storms should be moving to the northeast very quickly in the neighborhood of 50mph! That wouldn’t usually be a huge problem, but terrain and finding a decent road network will quickly become a big issue shortly after storm initiation.

According to the latest hourly RUC guidance in addition to the 4km WRF, storms will initiate around 4-5pm local time near the I-35 corridor and quickly race northeast into the sticks of east-central Oklahoma. Depending upon exactly where you are in the state east of I-35, you may or may not have a good road network or good terrain.

If enough moisture can surge into the OK/KS border, that may a good play for today based on terrain. I would normally say that playing the northern target would be a pretty big gamble on a day like this with such limited low level moisture. But mid level temperatures will be so cold (-25 to -30C) that it might not matter as much today. A tornado could touch down anywhere from central/east central OK to south central Kansas.

But in the end it’s late February and anyone with the ability to chase a low topped supercell in Oklahoma/Kansas with the potential to drop a brief tornado should take advantage of it.

Jim

Wednesday, 9 November 2011

 

 

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.

 

 

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.

 

 

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…

 

 

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

 

 

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

 

 

 

 

 

Wednesday, 24 August 2011: Early a.m.

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

 

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).

 

 

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.

 

 

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.

 

 

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….

 

 

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

 

 

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.

 

 

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!

 

 

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

 

 

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.

 

 

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

- Jim