Thursday, February 19, 2009

Pattern Change

It's coming!

Wednesday, February 11, 2009

Wash out!

Well, any hopes for a chase today appear to be washed out. Surface low is already moving into Illinois and ahead of it is nothing but a large area of rain. This is often the case for these marginal early season set ups.

Tuesday, February 10, 2009

Complicated Wednesday

I could be over anxious, but I'm trying to salvage some low-topped supercell potential tomorrow in Illinois and Indiana. My main fear was the squall line being our only hope for tomorrow, bringing a 6 AM wind threat. It looks like the squall line in Arkansas and Missouri is currently racing out ahead of the low and may actually wash out near the Mississippi River. We may see pulsing severity as it continues into KY, TN and IN, but it should race out far enough from the low to give some attempt at clearing ahead of the low.

By 10 AM, the low level dry punch should be located about 50 miles SE of St. Louis in SE Missouri. The area ahead of this in central and southern Illinois could at this time see some destabilization. 0-3 KM cape values in this area are spiking quite a bit at 18Z, which at this time is 1 PM. This is late enough to potentially see some low-topped minisupercells form on the SE side of the low in central and southern Illinois. At 21Z we see that area of 0-3 km cape shift into southern and central Indiana.

I'll likely stay at home and feel the situation out to avoid jumping to early just because I'm over anxious after a long winter.

I'd like to try and hug the warm front to maximize low level helicity and low level cape for any tiny tornado potential to be realized. I'll watch the area outlined by a Champaign, IL to Terre Haute, IN line eastward to a Lafeyette to Indianapolis line.

Timing and Location

How annoying the timing and the location of certain events can be. Though some may get lucky, many southern plains chasers are learning this today with a moderate risk issued, and tornadic storms likely to develop this evening. However, most of the potentially violent weather will likely be over poor terrain, and potentially nearing dark as the sun still goes down around 5:30 at this time of the year.

We here in the Ohio Valley will get our turn with the system tonight and tomorrow morning. While the a kinematic system of this magnitude will raise some eyebrows, the timing and location of this system couldn't be worse. Earlier runs were showing a very good April-like system coming into the area on Wednesday afternoon leaving a large warm sector over chaseable central Illinois. However, the opposite of what I had hoped would happen materialized and the NAM fell more into line with the GFS and the system really sped up.

Severe weather potential remains, and will likely unfold over parts of Illinois and the Ohio Valley. However, rather than being in the mid-afternoon with plenty of destabilization we'll likely be relying more on the kinematic side of the system to realize the severe potential. When this happens, more often than not the tornado potential is minimized and strong wind gusts rule the day. While some significant wind damage is a good possibility, it isn't exactly the cat's meow when it comes to chasing eye candy.

Then we have the location. I love high winds. I love nothing more (okay, I love a few things more) than to park it in front of a significant wind damage producing bow echo and watch everything get blown over. Given the time of the year, after a long winter I'll often take this over nothing. But again, the location is also screwy with this system. Rather than that nice fat warm sector over flat central Illinois, the prime area will likely be pushed a bit further south. The models currently have the warm front swinging as far north as Interstate 74 by 9 am. With such a high qpf forecast on the north side of the warm front I'm weary of buying into such a northward swing. This means that the prime area for severe weather will more or less ride right along the jungle that follows the Ohio River. Tornadic storms are possible in Tennessee and Kentucky, some of which is chaseable terrain but for this system I will not make such a journey.

All whining aside, should we really see such a northward push with the dry slot and warm sector tomorrow morning we may see decent severe weather possibilities in parts of central Illinois. I will be watching the Interstate 70 corridor from St. Louis, across south central Illinois towards Indianapolis. We'll likely see a large area of thunderstorms and rain develop around the Ohio River tonight, with the severe squall line forming in Arkansas at the same time. Severe storms will likely spread into southern Missouri later in the night with a northward push of the other convective area near the Ohio River, lifting the rain and thunderstorms into central Illinois. Towards sunrise, severe thunderstorms, potentially tornadic should be ongoing from St. Louis southward into Arkansas, to near Memphis. A couple strong overnight tornadoes are possible across that line and west overnight. Should the warm sector surge north fast enough, we may see a continuation of the severe area of thunderstorms across the southern half of Illinois, Kentucky and Tennessee and then parts to the east in Indiana towards noon. Again, should the warm sector clear out fast enough, I would not rule out a couple tornado reports from 6 AM to 1 PM from St. Louis to Indianapolis along Interstate 70. The more likely scenario will however be primarily wind damage.

With such a complicated scenario, it's best to ask me what I really think 24 hours from now.

Instead of chasing in Oklahoma, I'll likely spend the rest of today finishing getting the car ready for that epic first chase of the year. Should that first chase take place tomorrow morning, we shall see.

Monday, February 9, 2009

Annoying Teaser

It's funny how one 60F degree day can totally flip my mindset into thinking it's mid-April. Once that cold front passes through the state of Illinois on Wednesday afternoon we'll quickly be snapped back to reality. Nonetheless it's nice to get out in the warm air and get working on the vehicle. I don't have a long list of preparations for the chasing season vehicle wise, as I normally don't keep most of my equipment in the car permanently mounted at all times. However, after a long winter a thorough cleaning job was needed.

The exterior was cleaned today, and I'll likely spend the day under the sunny skies and 60-70 degree temperatures cleaning out the interior and doing what little mounting I need to get done before the first chase.

On the issue of that "First Chase", Wednesday is not currently looking so hot. The models are flopping around, but at this time have picked up a much faster trend that does not bode well for tornadoes, or storm interception. A squall line will likely develop in Missouri and Arkansas Tuesday night and race into the Mississippi Valley overnight and will likely provide us our best chance for convective excitement before the cold front passes through on Wednesday. Any afternoon SVR chances will likely be contained to areas far to the east in Ohio, Kentucky and Tennessee.

This might not have been the big "First Event" that everyone was hoping, but it's clear that spring is indeed just around the corner.

Sunday, February 8, 2009

Wednesday Convective Possibilities?

Now depends on which model you want to watch at this point. The GFS has sped things up, but now that this event is within the NAM time range it's showing a considerably favorable setup for this time of the year.

It shows considerable convective activity overnight across the area with a strong dry punch swinging into central Illinois by 18Z with sbcape values AOB 1500 j/kg by 21Z. Not sure if this will remain the case, but with a synoptic system as shown this would be more than enough for supercell structures and potential tornadoes.

Time will tell, as there are huge discrepancies in the models. The new run is out in a couple hours but at of the 12Z runs GFS says early morning rain and the system is in the Great Lakes by late morning. NAM says watch out around the Interstate 70 corridor in Illinois and Indiana.

My SDS goggles are on, but my instincts at this point are leading me to believe the NAM solution for now. Not necessarily meaning that I believe in a tornadic event across the area but given past trends the GFS often will hit timing fairly well at the extended time frame, and then speed things up around 72-96 hours before slowly falling back inline with earlier runs and other model solutions. Time will tell, but I wouldn't be surprised to see the system slow back down a bit on the GFS. Whether or not this brings severe weather to the area we shall see, but at least we'll see warm air in the area for a few more hours on Wednesday than if the low swings out of here quickly.

Tuesday, February 3, 2009

Warm air approacheth.

Many chasers are starting to get pretty stoked at the return of warm air to the mid section of the U.S. Several troughs are indeed lining up with their aim on the central part of the country. Whether or not this brings any early season severe weather opportunities remains to be seen, but warmer air will be making it's way into many areas.

Here in central Illinois we've got a decent snow pack, but should see much of this melting down by the weekend as temperatures reach the mid 40's, and potentially 50 in areas with less snow. A second trough will enter the region next week with hints of high temperatures in the 60s here in Illinois.

I'm not getting too excited about storm chasing opportunities for my own mental health's sake, but I will likely use the warmer weather to do some work on the car to get it ready for March. Someone in a thread on the Stormtrack forum brought up the fact that there really is no "Official Storm Season" launch date, but there are psychological barriers. For me, that date is generally March 1st. While there have, and will again be winter storms beyond March 1st, I generally see this as a day as the day when I consider all things possible, and allow myself to get a little more excited about the long term models.

Whether or not we see any form of severe weather in the coming week of troughs, the warm air will be a nice change.