State of the Chase Season: 2016 Edition

[Andy Wehrle]

Hoping the last few runs of the GFS were totally out to lunch, with an ugly Omega block/Plains ridging setting in out to the end of the run. Today's 12z run looks somewhat better, but glad my vacation isn't until late May/early June & also glad I chased the March 15th setup when it presented itself.

 

[Dan Robinson]

The system next Friday-Saturday appears shot thanks to that midweek system along the Gulf coast, followed by offshore flow aloft right up until the day the trough ejects. No real moisture return to speak of thanks to all of that, just a local play for those who live along the NM/TX border. This Sunday looks like a player that I'd consider if it wasn't a one-shot deal close to OKC on a weekend.

Also, has anyone noticed how consistent and in agreement the Euro and GFS have remained for late next week? I can't recall seeing such a long period of models showing the same general pattern that far out. If the pattern verifies, that will be quite remarkable IMO. Hopefully that continues!

 

[chrisbray]

Yeah these systems going through texas in the coming week seem to keep gulf moisture from getting paste the coastline. Amazing how it seems for the past week the models have been in agreement for this trough coming ashore next friday, but when it gets here the moisture return will be way less than ideal. After next weekend...not sure but the month of April is starting to look pretty sad.

 

[Andy Berrington]

Growing increasingly interested with the latest model guidance, particularly the 00z Euro, in the 4/15-16 timeframe for the High Plains (especially the W TX and the Panhandle). It is showing upper 50s dewpoints (caveat #1 for sure given the pre-existing pattern across the central/E CONUS) making it to AMA with some pretty impressive shear profiles in the low levels. These are associated with the height falls from the SW upper trough and LLJ intensification out of the SSE. Steep mid level lapse rates as you would expect this far west are also in place. Looks to also be a nocturnal threat with the Caprock perhaps providing an initiation source well after sunset, which has certainly occurred before especially with a lumbering, meridional trough like this with periodic vort maxes pivoting around its base. Synoptically, it bears reminiscence to some other events that have yielded fairly robust events in the region.

Something to keep an eye on since it looks like it may be a Friday/Saturday event in potentially favorable chasing terrain.

 

[Brett Roberts]

Although the trough late this week into the weekend is questionable for higher-end chase potential, given that it will become cut off from the main jet, I am very pleased to see the consensus on widespread heavy rainfall over the southern High Plains. Last night's GFS, GGEM, and ECMWF unanimously indicated 1-2"+ QPF over much of the Panhandles, E NM, W/C KS, and W OK. Some areas may receive >4" QPF by the time this cut-off low finally lifts out next week, according to recent runs. Assuming forecasts don't change dramatically (never a safe assumption when dealing with cut-off lows beyond 2-3 days out), this could be a big break for our chances with any setups in that region later in the season.

 

[Quincy Vagell]

Although the trough late this week into the weekend is questionable for higher-end chase potential, given that it will become cut off from the main jet, I am very pleased to see the consensus on widespread heavy rainfall over the southern High Plains. Last night's GFS, GGEM, and ECMWF unanimously indicated 1-2"+ QPF over much of the Panhandles, E NM, W/C KS, and W OK. Some areas may receive >4" QPF by the time this cut-off low finally lifts out next week, according to recent runs. Assuming forecasts don't change dramatically (never a safe assumption when dealing with cut-off lows beyond 2-3 days out), this could be a big break for our chances with any setups in that region later in the season.

This may be the only optimistic thing on the table for the remainder of April. While we remain in a messy pattern for the next couple of weeks, more or less, the long-awaited "pattern change" may be exactly what we don't want. Instead of eastern U.S. ridging, as was progged a few weeks ago, now the ensemble guidance hits western/central North America ridging going into May. I can officially say that I am now very skeptical of any significant change for the better in the foreseeable future. I hope I'm wrong, but...

 

[Craig Norris]

I wasn't sure where to place this but I thought this could be a valuable tip for future chases. Highway 50 in Kansas has tons of construction on it from Pratt to Newton. I know this is a heavily used thorough fare when chasing in Kansas but throw in the tractor-trailer traffic you all might want to avoid it


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[samuel stone]

I wasn't sure where to place this but I thought this could be a valuable tip for future chases. Highway 50 in Kansas has tons of construction on it from Pratt to Newton. I know this is a heavily used thorough fare when chasing in Kansas but throw in the tractor-trailer traffic you all might want to avoid it


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Highway 50 does not run through Pratt. Do you mean Kinsley? or st. John?

 

[Craig Norris]

Sorry 50 turning into 61 heading to Pratt. Worst stretch by far though is Hutch to Newton.


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[Quincy Vagell]

Back on track...

The next week or so is a transition period. We are seeing some severe today, including at least one photogenic tornado in eastern Colorado. More supercells are organizing in the Texas panhandle as I type this. Although the severe threat gradually wanes over the next few days, I would expect at least spotty severe each day into early next week, particularly across the southern Plains, including a tornado threat. Heavy rain from Texas to Nebraska (maybe even into parts of the Dakotas) will effectively work to knock out most of what was a developing short-term drought, which is another good sign. There should also be a minor "drying" period, so we're not inundated by moisture at all once. (Not to mention the threat of muddy/washed out roads may not be a big issue as the water has time to soak in)

Signals are there for a pattern change by late next week as a trough digs into the West Coast and ridging slides east across the central to eastern U.S. There is strong agreement amongst EC/EPS/GFS/GEFS/CFS that the pattern between next weekend into early in the following week should be supportive of severe and perhaps a string active of days. It's hard to say at this point if there would be a higher-end potential day in the mix, but given the setup, ingredients in play and climo for late April, such a scenario would not be surprising. The main focus is from the Plains into the Mississippi Valley, with further eastward progression somewhat of an unknown this far out. The EPS would like to maintain ridging in the east through the end of the month, which could keep the central U.S. relatively active to close out April. (take this with a grain of salt)

I think we are gearing up to start the peak chase season, meaning we start seeing chaseable events on at least a semi-regular basis. Details are subject to change, but given trends and model agreement for several runs in a row, the signs are encouraging.

The CFS dashboard is lit up for the last week of April and the pattern is at least broadly supported by the 12z EPS.

 

[chrisbray]

Yes, I have been watching for next weekend for a while now. GFS has been pretty consistent bringing a trough on shore on the west coast in the friday/saturday 22/23 for the past few days. Euro a bit slower, and CFS kind of all over the place. I am optimistic though.

 

[Michael Gavan]

It's either been a while, or basically never since the last time that I saw the GFS give such a strong signal 15+ days out, and maintain this much signal now at 7-8 days out. It doesn't mean a whole lot in the scheme of things, but the fact that it was enough for me to mark 4/23 on my calendar with the intent to chase whatever this event throws---a week ago, and to still be talking about it is a first for me at least. Painting with a huge brush here but based on watching past events, or rather 'signals' predicted well in advance the timing of certain features will probably be delayed by up to a day. In this case It may work to everyone's advantage, certainly early on the moisture won't quite be there in abundance. Should be interesting to watch this evolve.

 

[Paul Knightley]

There is quite a strong signal after next weekend on ECMWF EPS charts of a western US trough emerging - backed up by some repeated attempts at such a trough at the very back end of the operational run, for several runs.

 

[kevin-palmer]

I knew the last week of April would be an active period for severe weather ever since I booked a plane ticket for the East Coast.

 

[Jeff Duda]

I see the certainty with western US troughing towards next week. Details are of course always important. One good thing I see is a total absence of fronts getting anywhere close to the gulf over the next 1-2 weeks, thus allowing moisture to progressively build over the Gulf and southern/eastern US. So, once a stronger system finally comes through and opens things up, we could see a widespread warm sector for a severe weather event.