Tuesday, April 29, 2008

And now we anticipate...

We are in Forth Worth tonight. Same place as last night. Today we went to the Fort Worth Stockyards and a Texas Rangers Baseball game. Not what I mind doing but not what I wanted to do. I want to chase.

This spring has been outrageous in terms of its weirdness. Dry air beyond belief, not just at the surface but through the lower half of the atmosphere. Despite strong southerly winds today across Texas, we still only have dew points in the thirties. Mid 50's are close by the coast however and we still have 40 hours of recovery time. Gives you some idea on how deep the intrusion of dryness reached into the Gulf of Mexico. In January it would be strong. Near May it is ridiculous.

But we hope to make that all go away this Thursday with a major outbreak of tornadic supercells. At least, that is what the models are calling for. Here is how it plays out:

The closed low ejects into the southern plains and at the base of that trough a 50+ knot jet pushes into the increasingly warm and moist air mass. Model forecasts are calling for mid 60 dew points to make it toward the OK/KS border. Even if this is a little overdone, it is still pretty healthy.This results in CAPE's progged well over 3000 J/kg.

The positives: Shear is out of control. There is no doubt that storms will quickly become severe and supercellular. A cold front through IA/MO/KS will intersect a dry line through central OK into TX approximately along I-35. The triple point should establish somewhere in NC OK. This is the default no-brainer place to start looking. Storms should fire down the dry line. Given strong capping, good forcing is needed but should allow for discreet supercells, each capable of producing tornadoes, and some significant. 0-1 helicities exceed 150 J/kg and 0-3 values exceed 400 J/kg!

The negatives: Moisture is on its way back and it needs to be there to create a great environment. NAM overforecasts the dews by some amount and may be over zealous with the actual values. Lower dew points mean more difficult to over come the capping inversion. Although the models do not generate precip, there are adequate indications that convective forcing should take place. Also, low-level winds are progged to back with the development of a secondary low over northwest OK. The strength of this feature in actuality will determine how good the environment becomes. Models also indicate some cirrus overcast which will limit visibility and perhaps lower the heating. These details are yet to become apparent.

This will be May 1 and it is in an area that is due for severe again. I feel it will happen. I just hope we are at the right storm at the right time and acting safely!

On Friday, despite problems with convection that may be ongoing, there is a strong signal that IL will be in for a pretty intense severe weather episode. After that, we will be close to home and will probably be home a day early.


Monday, April 28, 2008

Still Waiting


So little moisture. Some sounding look more like January than late April. Snow in Chicago. Weird weather continues. I have not seen anything like this weather since I have been chasing. Extremely low wavelenghts have precluded aggressive return flow from the Gulf of Mexico and another big wave is set to attack. Wednesday would be outstanding if there were any vapor in the air. 700mb dew points are as low as I have ever seen in spring across most of the southern CONUS.

So we are now in Arlington TX. Up from San Antonio. We are going to hang around the Fort Worth Stockyards tomorrow and catch a Rangers game tomorrow night. Then off to OKC on Wednesday. I doubt we will chase Wednesday. Unless remarkable moisture return commences. But it won't.

Thursday, however, is still the big day and I hope we do it right. We hope the atmosphere does it right too. Friday...not sure. Midwest looks under the gun but it may be messy and early with a lot of ongoing convection.

Saturday....doubtful. Although there is some chance across parts of Texas. If the dprog/dt improves, it might be worth watching.

If not, we come home early.

Sigh...what a weird spring.

Saturday, April 26, 2008

Trip 1 Day 2 - Headin' to Texas

After a fairly unimpressive day yesterday, we slept in Springfield MO. Slow going in western IL toward STL but that is the way it is. Today, a good situation is unfolding in TX with the biggest problem moisture. The NAM seems to forecast a rapid increase and all the models are showing a strong convective signature.

Around the base of the main upper trough another strong impulse is going to make its way around the turn. As it does so, good wind fields will provide a good environment for supercells with storms as they develop. Moisture should become more plentiful so the tornado threat will improve toward sunset. We are hoping that storms will have a favorable trajectory along the returning warm front to ingest more vorticity before the secondary and main killing cold front overtakes all. We are hoping for a good lightning show overnight.

Our target will be toward ABI area or points a little further north. Will adjust after morning analysis. Might take in a Rangers game tomorrow PM before heading to San Antonio in the evening. Monday will be a down day before we head to Lubbock for Cagles Tuesday evening to set up for what may be a busy next few days!

Friday, April 25, 2008

Starting Out

Chasing from the start. Not the best set-up but not too bad. We are heading down I-80 and thinking about western IL. I will try to post more later but there are some good things and some bad things around. At least we should see storms today. Maybe severe.

But it is later in the week that gives me the most hope. Starting Wednesday in the southern Plains. While it snows in the north we will be somewhat warmer!

Wednesday, April 23, 2008

Chasing 2008

Well, time to start a blog for this years chases. I wish this spring had been a little more active. I am hoping for big things next week. Here are my thoughts tonight.

Right now, it looks as though we will leave the gates running. Given early week possibilities being slim, we need to take advantage of things while we have storms. As of now, this looks like the best scenario I can give you:

Friday...leave by 8AM and head toward southern IL/MO bootheel region. I am not sure how things will be in terms of tornadoes, but there should be a severe risk and a chance to get some big storms as a cold front comes through. (There is an off-chance we might actually chase around here a little earlier...) I would hope to stay in Little Rock overnight.

Now the cold front is a real problem. That is bringing cold air southward and dry air. How dry the air gets will matter because a second upper-level disturbance which will swing toward the southern plains with a surface low progged to develop in the OK Panhandle. This will slow the southward push and allow for some instability to make its way toward that low. Dynamically things might be interesting but how much moisture we can get back will be key. I am not sure how good it will be...high based storms might be worth a picture or two. However, overnight, here might be a nice MCS that forms and will give us a good lightning show. We will watch that
because after that, things will shut down for a few days. Cold air will plow into the Gulf of Mexico. We can hope that it is quick to recover because the flow toward Tuesday starts to get much better. I would suggest heading toward Dallas or San Antonio or do something fun Sunday and
Monday. The Texas Rangers have an afternoon game on Sunday. We can get 5 dollar tickets.

Then hope...for moisture return quickly.

But the good news...that at least by Thursday there should be a couple of good days for chasing. I mean...i am looking at the prospects of at least two good days of excitement, if not three. We can also hope for something interesting on Wednesday which means we could have a very good trip.

At least that is how it looks to me right now.