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storm chasing

26 May 2011 Storm Chase – Chase log and pictures

Had some fun chasing in southern PA… originally had targeted further east to stay out of the more mountainous terrain, but we worked over to I-81 S from Hagerstown, PA late in the afternoon as cells were getting tornado-warned in MD and WV. We intercepted a cell that ended up producing a tornado about a mile away from us to the NE of Marion, PA, but unfortunately rain obscured our view of the tornado yet again. Prior to the tornado east of I-81, there was also downburst damage west of I-81, which also included an overturned tractor-trailer on the interstate. It was a messy (weather-wise) day, but it was a fun day. We got a glimpse of a loosely-organized funnel cloud, but it didn’t turn out well in my video, so that’s been left out of the captures.







23 May 2011 Storm Chase (Pt. 1 of 2) – Summary and videos

After debating between a PA and southern VA target, Jason and I decided to head south towards the better instability. While several tornadoes were reported in PA, the day was not a disappointment as we caught multiple funnel clouds and a possible tornado on video.

We started the trip stuck in traffic. After heading out from home just after 1:00pm, we got on I-495 and had just gotten on the American Legion Memorial Bridge when traffic halted in front of us. Apparently, there was a serious accident just before the exit to I-395, and the accident basically blocked all of the lanes. We were on the bridge for over an hour until emergency crews re-opened one lane (not even a lane… just on the right-most part of the pavement) and we got through just before the real rush hour traffic hit the southern end of D.C. around 3:00pm. We made good time getting down past Richmond into SE Virginia.

After watching storms initialize in SE Virginia (as we were arriving into the area), we could see more storms popping up along a SW-NE oriented boundary (the short wave?) stretching down into NE North Carolina as the afternoon was coming to a close. We headed into North Carolina and tracked a storm for nearly two hours while it kept up a wall cloud and tried to produce tornadoes here and there. We can’t really know for sure whether or not we got tornadoes on camera since the terrain blocked us from seeing any possible ground circulation, but there were a few times where we thought it was pretty darn close.

I might make a clip video later, but Jason already accomplished that with a lot of similar footage, so I might just be lazy and go for the screen grabs instead. The first video is my continuous footage of the rotating wall cloud and funnel cloud(s)/possible tornado. Jason’s video takes us through most of the exciting part of the chase, with a nice funnel cloud starting around 8:21 on the video (shortly after I stopped filming to get our location to report the funnel cloud). These parts of the chase took place about 2-3 miles WNW of Ahoskie, NC along Rt. 561.

You can skip past the little FBI Copyright Warning screen in the beginning of his video…

April 28, 2011 Chase Pictures

Just the one quick upload for now… will add more to this post as I get through footage. Finishing up the final prep. for the Plains chase!

Got in a tornado-warned cell just SW of Elizabeth City along Rt. 17. It looked like it could be fun, but aside from some vivid lightning and a non-rotating wall cloud it wasn’t much to see.

This one was the last cell of the day for me… I think it was severe-warned but definitely not tornado-warned. I was in a tornado warning in an earlier cell and was in perfect position along Rt. 17, but it didn’t produce. Lots of lightning, and even a double rainbow at the conclusion of the last cell. It was a long 14-hour chase by myself, but it was fun and I had a good day despite the lack of tornadoes.

We leave on May 1st

After some deliberation, Jason, Ian and I have decided to leave Sunday, May 1st (returning on the 15th). Jason and I picked up a few chase items for the trip, and everything’s on schedule as of now.

The models are still trying to decipher the pattern going into the first week of May, but things are trending in our favor. Six days left!

I’ve been kind of ignoring my Sunday/Monday regular updates in recent weeks… I’ll get back on those once the Plains Chase is complete.

A tenative look at the first week of Plains chasing

If we are able to leave on the 30th or really early on May 1st, it looks like we could hit up a potent storm system in the Midwest on the 1st-2nd before making it all the way into the Plains. After that, a progressive upper-level ridge in the West could bring a lull in the action until another system tries to push it east and break it down going into May 6th.

On the flip side, let’s see what the models have been doing wrong lately. Past the day+7 lead time (starting in week two), the models have struggled to capture the effects of the soil moisture across the South and Southeast, which has helped to keep temperatures above normal in the Southern Plains, Southeast and southern Mid-Atlantic. Conversely, the below normal temperatures in the northern and western areas have come in cooler than forecast, which would lead me to think that the -PNA influence and soil moisture could alter the storm track that is presented by the models. While not negating the transient ridge in the West during the first week of May, it could definitely verify weaker than anticipated, which would allow the ridge to break down more at the end of the first week of May when a storm system moves in off of the Pacific. This will hopefully reset the pattern and push us into an active severe weather pattern as we head into the second week of May.

Planning and Forecast for the Storm Chase Expedition

The start date for chasing is being finalized as I type this, but it looks like Jason, Ian (will be bio’ed later) and I will head out from Maryland on April 30th, with the plan to start actively chasing on May 2nd (so long as there are storms on that day). We be out chasing through the 13th, which will give us 12 full potential chase days before we have to start heading back to Maryland.

There’s a few things still left to buy, like a sleeping bag and duffel bag, but other than that there’s just prepping Jason’s car and finalizing the itinerary.

I will be posting a daily blog from start to finish for everyone to follow along and enjoy. It should be an interesting two weeks!

Looking at the climatological statistics and the teleconnection forecasts, it appears as though early May could be quite active in the Central Plains, Midwest and Tennessee Valley regions.

The NAO and PNA are forecast to be either negative or trending negative as we head into early May:


 
Below are the loading patterns (ridges/troughs) that correlate with the NAO and PNA in spring:


(The height anomaly maps are from the Climate Prediction Center)

 
The images are the positive phase correlations of the NAO and PNA. Warm colors indicate positive height anomalies, and the opposite is true for the cooler colors. If you invert the colors for the negative phase, you can see that the -NAO induces a trough over the Rockies and that the -PNA induces a ridge over the Southeast. Together, they help steer the storm track through the Central Plains and into the Midwest, as seen with the red arrows that are added to the images on the right-hand side. This track is quite favorable for severe weather.
 
Here is the latest U.S. Drought Monitor map:

 
It shows dry conditions over the Southern Plains and parts of the Southeast. I won’t go into it much, but I’ll quickly just say “drought breeds drought” in that the drier areas on the map will have a tendency to stay dry, which would indicate that most of the storms will form further north in the Central Plains and the Midwest/Tennessee Valley regions. In a hand-waiving manner, the drought conditions will help keep the storm tracks further north, which will help support the -PNA pattern.

We are also coming out of a strong La Niña winter into a weak Niña or neutral ENSO state, which is climatologically-favored to produce more active severe weather seasons.

The U.S. has been quite active with low pressure systems in recent months as pockets of upper-level energy that form these systems continually move onshore into the West every 2-4 days. All together, this should provide us with an active May pattern, with plenty of severe weather in the Central Plains and Midwest.

16 April 2011 Storm Chase (Pt. 3 of 3) – Chase Log

Jason Foster and I left Gaithersburg, MD a few minutes after 8am to make the trek down to North Carolina for what turned out to be one of the biggest East Coast tornado outbreaks in history. The plan was to be near Wilson, NC around 12:30-1:00pm to eat and begin our chase. However, being the first day of Spring Break for many, I-95 southbound was clogged with traffic, sometimes coming to a complete stop all the way from Washington, D.C. down through northern NC. At one point we even resorted to using back roads to help make up for the time lost in transit. We finally arrived at our target destination over an hour later than planned after 2:00pm when discrete supercells were just starting to get organized to our south and west. Having no time to stop and eat, Jason and I quickly fueled the car, grabbed some snacks and headed towards the cell that was tracking towards Raleigh.

We headed towards the Raleigh cell as the Raleigh metro area was getting tornado warned. Being a bit behind the cell, we had to play catch-up. Visuals weren’t spectacular as the circulation was rain-wrapped as it pushed through the southern suburbs. The cell showed signs of cycling, so Jason and I continued with it into eastern Raleigh, where we spotted a funnel cloud and possible tornado. Since trees were in the way, we could not see whether or not the circulation had reached the surface while we were observing it. Shortly after this circulation became rain-wrapped as well, so we headed back south to catch the nearest of several storms that had active tornado warnings.

After dropping south to come in through the western edge of the core, Jason and I turned back onto I-95 to get to the second storm’s circulation, which had also become rain-wrapped. The cell weakened substantially and didn’t look like it was going to cycle, so we dove back to the southeast to get behind another storm.

The third storm had produced a tornado over Snow Hill not too long before we had arrived in the outskirts of the town. A couple miles NW of town we came upon 3″ hail, took some quick photos and measurements and headed SE. We were stopped just short of town where many emergency vehicles were already on scene. A small community and a couple of commercial buildings had taken heavy damage by a small, concentrated tornado. Some of the homes had very little damage, but two homes in the direct path of the tornado had been completely ripped off of their foundations. One of these houses was still relatively intact within the property lines, but another house was pretty much gone.

Jason and I spent some time documenting the damage before hearing of another storm entering the area. This storm passed us to the east, and we headed off to try to catch the cell as it traveled NE at ~50 mph, which was actually one of the slower storm motions we had seen from the many warnings that had been issued in NC that day. Alas, the road network was not favorable for an intercept, so after a short chase with the daylight fading we started to trek back towards I-95 to get back home.