Quiet For a While

[matt patterson]

i have a thought (would be a theory if i had testable material but i dont) that the reason that we are seeing some sort of chain reaction in regards to severe weather placement. Last year areas of western tx/ok/ks and ne saw very little in the way of severe weather. There were several days when the dryline would race across the west and set up along a emporia to tulsa to denton line which is where initiation would occur. the dryline would move so fast because of the very limited moisture in the west. im wondering if that becasue the drought is soo severe that the ground was eating that moisture up and in return we have no or very few storms. this year the situation is not much better and already with the first few systems we are seeing a similar trend set up for 2007. Storms with great dynamics and starting in E OK/ks/tx and moving into the ozarks and beyond. The amount of moisture that it is going to take to pull the west out of this drought is extreme and although they did get some snow this winter and some recent rain, there has been no resolution to date. Im wondering if it is goign to take the plains a while before they become active again.. think about it... if each year we get a little help (1"-4") surplus of precip, how long will it take before we are back in the hunt? If this were a thesis statement it would read "The impending drought in the western parts of KS/OK/TX is resulting in a faster than normal progression of sfc features across the area allowing for the better dynamics to impact areas East of the traditional Tornado alley. This creates a much higher impact of severe weather across these regions. The traditional tornado alley may take several years to recover from this lack of moisture and have the products in place to produce more than a handful of severe weather events per annum." Obviously im not an English or Letters major, but you get my point.

I would also like to look at the severe weather events that occured after the dust bowl. If states east of OK/KS/TX recieved above average numbers then that would help my point some.

 

[Justin Teague]

One of the more serious issues that I saw last year was vertical mixing of the moist layer to the point that it was insufficient for true surface based convection. There were plenty of days where chasing was possible in the traditional tornado alley, but IMO, the lack of evapotranspiration and other microscale process associated with ground layer moisture were lacking, or non existant. Concerning the dryline moving to E. OK, I feel that it is more a result of the synoptic scale features than the meso/microscale features. (i.e. closed lows with sweeping Pacific fronts and those warm fronts the stretch across 3 states). It takes quite a bit of forcing to push a true "dryline" through the wheat belt and the remainder of E. OK and N. TX.

In regards to the current drought conditions across Oklahoma and N. Texas, I would say that we are miles ahead of last year in soil moisture content, due to the fact that we haven't had the extreme wildfire issues that we were having at this time last year. Hopefully somebody with more knowledge on this subject will step in and enlighten us.

 

[Brian Stertz]

Climatology-wise...March is a month typically when you get maybe a significant event or two in before March 20th. Then things start rising dramatically with severe wx events as you approach April 1st. Then comes the month of April which can be a wild card of sorts for severe wx events. Some mention has been made that this year's pattern may end up mirroring that of 1998. Things got pretty much active after March 20th that year. I know if it truly is a carbon copy of 1998 where I will be on June 23rd Know what I mean Mike H.

 

[Michael O'Keeffe]

Brian has some good points there.

IMO I think this season has in a way brought me to think of it being a 1995 or 1999. The very early season setups such as February 23-24, 28 and March 1 remind me of the Janruary 1999 outbreaks as they were so early in the season just a bit further west and south. If this is true, as of now is pretty much a wishcast. Like Brian put, things really got going in 1999 after April 1 like a typical tornado season. Though I don't think the South Plains drought is totally dissapeared, it wasn't as wet as could be in 1999 either. Lets hope for this to be true and if it is a normal to slighty above normal season may be in store.

 

[matt patterson]

Of course then if we are wishcasting then i would say that this is the beginning of the 3 yr supercycle!!!!!. Regardless of all the climatology we need to see some real quality moisture and less ridging along the gulf coast. This all seems to come to light if you believe in the pattern forecast for the mid to late part of this month. Is there any data or does anyone know of years that we have such as 2007 where we are going from an El NINO` to a LA NINA`? I am wondering what that may do since its forecast to offically start in May

 

[Ilya Neyman]

It's important to realize that the synoptic-scale pattern is largely responsible for mesoscale weather situations and storm formation. You could have all the moisture in the world, but if you've got a big ole ridge sitting on top of you, your chances of seeing active weather (i.e. severe weather) are pretty low. There are large factors that determine the particular upper-air pattern that sets up, such as ridging, troughing or blocking. Last year, and the year before that there seemed to be quite a bit of blocking that persisted for months. One of those seasons (2005) brought many intense storms into the West Coast with California being hit especially hard as intense troughs developed offshore and moved inland, as a ridge was often built up over the Rockies and a strong Hudson-Bay Low dominated the eastern half of the nation with dry and cool NW flow for the Plains. Last year, another block set up and we just had a huge dry high over the inter-mountain West and Plains. The drought was a result of this pattern.

If the Rocky mountain ridge breaks down and turns into a pronounced trough, even if the ground is virtually arid, strong sweeping SEerly winds would advect abundant moisture out of the Gulf of Mexico (provided there is enough time for this to occur) and set the stage for active convection.

In thinking, reading about this and talking to experts the second part of the equation is of course surface conditions, with how moist or dry the land is being a pretty interesting factor when it comes to the evapo-transpiration process and the possibility to have dewpoints higher by several degrees if there is ample soil moisture across the region. The difference of several degrees in dewpoints can mean the difference between a severe storm and a tornado sometimes, and can even factor into breaking the "cap".

As far as last year went, true we were in a massive drought but that was a result of the whole scale atmospheric pattern over N. America with systems flying through quick and not digging far enough west to allow for moisture to stream in over the Plains. As they swept by us, the moisture set up just to our east, and the big-time stuff resulted.

We are really in a different situation this year with respect to soil moisture. While there are still pockets of drought over OK, western TX, and the northern Plains this is more a result of cumulative years of drought rather than the past several months, which have been notably wetter-than-normal in OK. In addition, look at the snow pack that is STILL over western KS and CO! This is from the series of snowstorms dating back to December. As it melts the water will flow down the plains from west to east in streams and further add to the soil moisture across the Plains. There were quite a few times this winter with snow/ice pack over a lot of the Plains which has definitely added to the ground moisture situation. Additionally, we were locked into cold weather for so long this winter, with 20s and 30s and snow/ice versus the 60s and 70s with dry wind and fires of last year. Further, a significant snow pack has set up over the Rocky Mountains this go-around. I have heard theories with regard to that *possibly* reinforcing troughing and at the very least sustaining/helping mid-level cooling crossing the Rockies.

Looking at the gfs, it's showing hints at a period of possible rain/storms to get going and last several days around the Red River area with slow moving troughiness and a stalled-out front toward the end of the week.

Interesting thread!

 

[matt patterson]

I started thinking during my managerial accounting class and wondered what the drought conditions were like from March to March of the current year (I.E. March 2006-March 2007) and whether or not those years had more or less than average Tors. I know its not a solid reason but kind of neat to look at. I found the historic drought conditions and recorded every other year for the last 10 yrs. Below each link is the total tornadoes for that year.

1996- http://drought.unl.edu/monitor/spi/1996/12mar96lg.gif
Total Tor-1173

1998- http://drought.unl.edu/monitor/spi/1998/12mar98lg.gif
Total Tor-1424

2000- http://drought.unl.edu/monitor/spi/2000/12mar00lg.gif
Total Tor-1167

2002- http://drought.unl.edu/monitor/spi/2002/12mar02lg.gif
Total Tor- 941

2004- http://drought.unl.edu/monitor/spi/2004/12mar04lg.gif
Total Tor- 1819

2006- http://drought.unl.edu/monitor/spi/2006/12mar06lg.gif
Total Tor- 958

2007-from last march to January 2007
http://drought.unl.edu/monitor/spi/2007/12jan07lg.gif
Total Tor thus Far- 151

 

[Michael O'Keeffe]

These are very interesting Matt. The closests I could find that resembled the latest drought map was 2004. Hmmmmm....oo who am I kidding it couldn't happen again.

 

[Dustin Wilcox]

I know I am fishing with out bait here, but the long Range GFS gets pretty interesting as we near the 21 and 22, definitely not even close to considering its solutions factual this far out, however it is a trend that will need to be monitored as it could be a possible indication that the zonal flow pattern may begin to change as we near the latter portion of the month.

 

[Andrew Pritchard]

*looks at calender*

Wow, it's March 5th and we are already comparing this "season" to seasons in the past.

Is it me, or do chasers get more and more antsy to make a comparison for everything each year?

 

[matt patterson]

i wasnt trying to make comparisons or predicitions of any kind, just showing a peice of data that relates the drought data to that of severe weather, more specifically tornadoes. More than anything it was just something im interested in. A comparison cannot be made because we have yet to start our severe weather season.

 

[Andrew Pritchard]

I know Matt, I wasn't talking about your post but rather the posts that actually said this reminded them of X year.

That and of course how every single severe weather set up looks like X set up from X year, or how X storm looks just like Storm Y from year X... ... you get the idea.

No harm done, just makes me wonder why nothing can just be seen as unique anymore... everything has already been seen apparently.

 

[matt patterson]

Ok. I think climatology is very important to remember when looking at severe weather, however we must also remember that there would be no such thing as climotology if all the set ups and systems were identical.

 

[matt patterson]

Did anyone else notice how the GFS keeps the moisture around into next week with 55tds asd far north as NE???? This may prove to be mighty nice for the next system that comes about!!!!!!

http://www.rap.ucar.edu/weather/model/displayMod.php?var=gfs_sfc_dewp&hours=hr132hr156hr180

could be FUN!