Wednesday, 23 April 2014

Severe weather chances in the USA increasing

The central USA has had a very quiet start to the severe weather season. Indeed, since 'modern' tornado records started (in 1950) the previous latest date that the first tornado fatality occurred was April 21st, which was in 2002. In 2004, it was April 20th - that streak ended abruptly when 8 people were killed in Illinois.

Through today, no deaths have occurred thus far this year, which is excellent news, and marks this year as a record in that regard. However, it seems that a multi-day, multi-faceted severe weather episode is about to unfold. As the first image below shows that an upper trough will move into the central USA today, followed by a much more substantial one this weekend/early next week, as depicted by the ECMWF model, and courtesy of MeteoGroup.


Moisture return has commenced from the Gulf of Mexico, although not yet that robust. By mid-afternoon, dewpoints in the western Plains will be around 15C or so, which, beneath steep mid-level lapse rates, should yield 1000-1500 or so J/Kg of CAPE just east of the dryline, and with reasonable shear, high-based supercells capable of large hail and damaging winds will be the prime threat from Texas to Nebraska.

Stronger moisture return will commence on Saturday as the major upper trough approaches - dewpoints east of the dryline in Texas, Oklahoma, and Kansas should be in the high teens by peak heating on Saturday, with 2000-3000J/Kg, or so, of CAPE amidst increasing deep-layer shear. Supercells capable of very large hail, strong winds, and a few tornadoes seem possible.

By Sunday, strong moisture return through the lower Mississippi Valley, and perhaps eastern KS/OK/TX (depending on the eastward speed of the system) should yield 1500-3500J/Kg of CAPE, or so, amidst strongly veering wind profiles. Supercells may grow upscale into a severe squall line - initial activity poses the risk of strong, long-track tornadoes (dependant on how much convection develops within the return flow).

By Monday, the risk area may have shifted eastwards towards Alabama, etc - both ECMWF and GFS's overall pattern is fairly similar, and one which would support a continuation of strong moisture return (dewpoints 18-21C) amidst strong deep layer shear, and strong low-level shear. Another day of supercells with a risk of strong tornadoes is possible. The chart below shows ECMWF's 500 hPa heights (solid lines), surface dewpoints (colours), and  850 hPa wind barbs for late afternoon on Monday.





In summary, several days of severe weather are likely in the central and southern USA starting today, but Saturday to Monday looks like being potentially significant multi-day severe weather event.

Thursday, 6 June 2013

Home!

Hello. We've just got home from the USA. Happy to be home, sad to have left. The events of May 31st have left an indelible impression on us both, though.

Wednesday, 5 June 2013

Almost time to leave

Hello. We did most of our packing last night. Just a few bits to do this morning and then it's off to DFW for the flight home. It's been a full on trip this year with great memories and sad ones too. Certainly not one which will be forgotten.

Tuesday, 4 June 2013

June 3rd report

Short: Intercepted several storms in the Oklahoma and Texas Panhandles, culminating in a stunning supercell.

Long: We awoke in Amarillo, and I decided to dust off the Speedos and do a bit of morning swimming - annoying kids in the pool meant I only swam for a bit before my annoyance levels took me back to our room for coffee.

We left Amarillo around noon/midday/1200, whatever it's known as, and headed north towards Guymon, Oklahoma. We were targeting the Panhandle region, as moist upslope flow combined with weak lift from an upper system meant that scattered showers and thunderstorms should form, and then become severe as they moved east and south-east into somewhat moister air.


After lunching in Guymon, where it was 38C (!), we headed a bit north and east, to just east of Hooker, Oklahoma. We then spent a while watching convection try to form but having a tough time. My mood become a bit despondent with it all for a while but spirits were lifted as a storm to the north-west took on a more solid look (above shows me watching it starting to form). We headed north, and started to see CG lightning coming out. Here is a lucky shot I took (below).





A number of our UK storm chase friends were also on the storm, and turned up! 



After a while we went our separate ways, and we headed east, to keep viewing the storm. However, it became clear that, whilst nice looking, it was going into a region where it would be tricky to keep following it by road, so we dropped south onto a new storm. We noticed on the Spotter Network that our friends Nathan, Pete, and Steve, had stopped, and the radar looked very interesting - we decided to drop down to see what had got their attention. It was a stunning supercell - we already had realised it was a supercell from the radar, but one look confirmed it. We pulled up next to them and spent quite a while in one place documenting it - this was south of Beaver, Oklahoma (below).



We then had to drop south, but stopped again to watch and document it some more (below). Soon it became apparent that we needed to get south and east before the angry RFD got us, so we headed down to Booker, where the sirens were sounding (the storm was warned for 80mph winds), and then east. After watching it some more we decided to leave it after dark, and we went our separate ways. Helen and I ended up in Elk City, and a brand new Sleep Inn. No places to eat though, so it was dirty microwave burgers and chips from Walmart! A far cry from the Big Texan last night! One more chase day tomorrow and then it's to Dallas on Wednesday for the flight home.


Monday, 3 June 2013

June 2nd - is this the way?

We decided we would head to Amarillo today as we didn't want to head miles south-westwards into New Mexico. It gave us the chance to do two things: visit the Palo Duro Canyon State Park, and eat dinner at the Big Texan Steak Ranch - these are both things that anyone visiting the Amarillo area should do.

Needless to say our minds were in a fair degree of turmoil following the tragic news I conveyed in a previous post - it was almost a continuous cycle for me, one of thinking it can't possibly be true, then realising it is, and then trying to accept it, and then again. And I didn't know them personally - I can't begin to imagine what those that do are going through.

The visit to the canyon gave us plenty of quiet time to enjoy the scenery and to take it in, and savour the moment. One must always savour such moments, indeed, all moments.

We spent a very pleasant several hours taking pictures, driving around, and getting out and enjoying the Texas sunshine - it seemed a million miles away from tornadoes and tragedy.

We then headed to Amarillo - trying not to have the infamous song going around in our heads - and then headed to the Big Texan, for a very nice steak. We saw Paul Botten, Tom Lynch, and their chase party and had a nice chat with them about everything that's happened recently.

Tomorrow brings a slight risk of severe storms across quite a large part of the High Plains. We'll pick a target region in the morning but far SW Kansas looks a possibility at the moment.


Sunday, 2 June 2013

To Amarillo amongst a tragic loss

We went to bed last night just as the news was breaking within the chase community that three of its most experienced and revered chasers, Tim Samaras, his son Paul, and their chase partner Carl Young, were killed in the El Reno tornado on Friday. Waking this morning made me hope it had been some awful dream but sadly it wasn't. The chase community has been shocked and stunned by this. Those with no clue about chasing will likely be quick to criticise what they deem as being a reckless and dangerous pursuit. Sure, getting close to a tornadic supercell is never going to be risk free, but these were people with masses of experience, and who were in it for the science as well as the fascination of being close to such a force of nature. We can only offer our sincere condolences to all their family and friends...we did not know them personally but within the chase community we obviously knew of them and their work intimately. RIP.

For us, today is a quiet day. We're heading to Amarillo and the Big Texan for dinner, but beforehand we're going to have some quiet time at the Palo Duro Canyon.

It has been a tough time to be a chaser but we have to continue doing what we love to do.

June 1st

We didn't do any weather type stuff today. We drove to Lubbock as there's a small chance of severe storms west and southwest of here tomorrow. It was a nice drive and it was sunny the whole day! We saw a couple of dust devils and stopped at the place where our windows got blown out earlier in the trip, just to see what it looked like outside a storm.