2012 Long Range Model Discusssion (> 7 Days Out)

[Eric Bucsela]

Very nice to see good agreement between operational GFS and EC 9-10 days out! For sure it's the most western troughiness the models show for the entire forecast period, and given the consensus, it seems likely - to me at least. Hopefully it is part of a pattern change that will also eventually kick out that Gulf low.

On the other hand, not seeing much good news today from CPC in their 8-14 day outlook - still hot over the West and cool near the Gulf. But we're really reading tea leaves at this point, and it's a volatile time of year.

 

[Derek Weston]

Very nice to see good agreement between operational GFS and EC 9-10 days out! For sure it's the most western troughiness the models show for the entire forecast period, and given the consensus, it seems likely - to me at least. Hopefully it is part of a pattern change that will also eventually kick out that Gulf low.

On the other hand, not seeing much good news today from CPC in their 8-14 day outlook - still hot over the West and cool near the Gulf. But we're really reading tea leaves at this point, and it's a volatile time of year.

See nothing on the GFS 9-10 days out. Bit of energy on the Canadian border... if that's what you're speaking about.

Not that I'm overly worried, I'm sure things will work out.

They always do, except when they don't.

 

[Dan Robinson]

FWIW, last week both the Euro and GFS agreed for several days on a western upper low/trough spreading SW flow >40kts over the Plains for multiple days, peaking Monday and today. I was gearing up for a second Plains trip (scheduling vacation days, etc). Two days later, that pattern was gone on BOTH models - and here we are.

I'm a total long-range model junkie, but for planning purposes, past 5 days it really is a wishcast. Only 1 out of 3 times does a +5 day forecast verify in the spring, in my experience. The good news is that can go both ways - bad patterns can turn good just as fast as the good ones turn bad.

 

[Mark Blue]

Don't really like the EC 500 hPa pattern. With that solution there should be a weak front located somewhere across the northern Gulf blocking juicy (i.e. 68-73 deg f) dewpoints from returning to the central plains. Color me unimpressed for severe potential across my neck of the woods through mid May. Models do change and moisture is underforecast (and over ) so not throwing in the towel but don't see any huge outbreaks within the current temporal model domain.

Good point Kelly about the moisture return for that time frame. I got excited to see the western trough and didn't examine closely enough that pesky low hanging around the Gulf. That would jack up the deep moisture return we need, but it's still a few days out. I seem to recall a similar setup a couple of years back where Jeff Snyder posted about a pesky Gulf low, so I shouldn't have missed that element. I'll take some time to look at the model solutions later today to continue our discussion. Thanks everyone for posting as I enjoy these types of discussions and learning more and more as each year rolls by.

 

[Mark Blue]

I'm going to dump the 16th and just focus on the 17th and 18th (especially the 18th) since it was mentioned upthread by a few other posters. Here are the 500 mb/hPa model solutions from the GFS and ECMWF for those two days for the 12Z run. It looks like things have changed in appearance, especially the GFS for the 17th. I have to run an errand but wanted to get these out to see what the "long range model junkies" are thinking.

 

[Eric Bucsela]

I'm going to dump the 16th and just focus on the 17th and 18th (especially the 18th) since it was mentioned upthread by a few other posters. Here are the 500 mb/hPa model solutions from the GFS and ECMWF for those two days for the 12Z run. It looks like things have changed in appearance, especially the GFS for the 17th. I have to run an errand but wanted to get these out to see what the "long range model junkies" are thinking.

Today's ECMWF ensemble actually looks marginally better than the deterministic forecast for that period and is probably more reliable this far out. But again today, CPC's take on the models doesn't suggest a major pattern change in the works. I try to hold myself to a personal rule of thumb: don't get excited about any forecast beyond about 6-7 days for ECMWF and 5-6 days for GFS. And that's just the approx synoptic pattern. Knowing the critical details - which can make ALL the difference - means MUCH shorter time scales.

 

[Mark Blue]

I'm just going to keep watching and hoping. Today's ECMWF for May 18th is giving me a little hope for then and beyond. The 0Z looks better than the 12Z, but I don't usually pay too much attention like I have in the last few days. The 12Z almost looks like a flat line except for a shortwave or something out west and the pesky low hanging tough to the east. What do the experts think?

 

[Dan Robinson]

I honestly am not optimistic yet. The past few runs have any good SW flow from that western trough *way* up north. The eastern upper low/trough is going to make it hard for deep moisture to make it all the way north to the upper support. At least it shows a western trough out there. With any luck, future runs could show the eastern trough fading and allowing the western one to move in. Not seeing that yet, though.

EDIT - I just saw the 12Z EC, not much of a western trough there now out to the 19th, not much encouraging upstream either it appears.

 

[Jeff Piotrowski]

The EC/GFS maybe some severe May 19-21 then better setup for the central plains after May 28th. Major jet energy will drop in the NW/US late in the month and set the stage for severe weather in the plains May 28th-June 4 time frame.

 

[Mark Blue]

I just wanted to throw in a quick thank you to everyone involved in this thread. This is one of the threads I enjoy and look forward to most every year (all kidding aside). Whether a member is a heavyweight or newer chaser all questions and thoughts are welcome IMO, as I'll be the first to admit that I am not an expert forecaster and enjoy hearing from anyone who has an opinion on this subject.

 

[Warren Faidley]

It's always bad news when this thread pops-up!

W.

 

[Kelly Sugden]

This thread happens every May because people freak out about a little quiescent weather. FWIW, the worthless GFS shows a tropical system developing way out in the extended and moving out of the NW Caribbean. LOL. That model is a joke. If that does come into fruition (which I'm guessing it will not) then that would be bad moisture trajectories. I still stand by the ECMWF solution with a weak front/low across the northern Gulf keeping any decent moisture away from the Central Plains probably through the next 10 days. Any attempt to guess thereafter is simply that... a guess. For example, I guess that there will be severe weather reported somewhere across the Plains between now and Dec 2015. To say it's going to get busy at the end of May is a just a nod toward climatology, anyway. There has been a trend in the EC over the last few days towards western trough amplification, however, I am personally still concerned with BL moisture further downstream. Time will tell cause the EC has been wrong before (although not near as wrong as the GFS). Yay for having access to hi res ECMWF.

K.

 

[Marcus Diaz]

Its pretty funny watching how people rely SO MUCH on models that have a history of changing drastically each run. Just play it by ear, and don't sweat it. Its not like we're not going to have any more severe weather from now on until the end of time. I'm not going to worry about how May will play out until 0z June 1st.

 

[Kelly Sugden]

Paying attention to each model run (perturbation) is pointless. Look for trends and ensemble trends. Using the NAM past its mesoscale design is foolish as well. It was not nor is intended for use on a synoptic timescale.

 

[Mark Blue]

I still stand by the ECMWF solution with a weak front/low across the northern Gulf keeping any decent moisture away from the Central Plains probably through the next 10 days. There has been a trend in the EC over the last few days towards western trough amplification, however, I am personally still concerned with BL moisture further downstream. Time will tell cause the EC has been wrong before (although not near as wrong as the GFS). Yay for having access to hi res ECMWF.

K.

I agree with your assessment for the next 10 days or so Kelly. I sure wish I had the access you have to hi res ECMWF model data, as that's a real bonus to have in the old toolbox. If that Gulf low (as we've been calling it) stays around you are absolutely right about the lower level wind trajectories - they will be out of a northerly direction along the Gulf coast and the moisture gates will be slammed shut on any systems upstream or out west. It also looks like the jet stream energy is too far north much like it was during Vortex 2's first year out (May 2009 IIRC - think Canadian border). In any event, discussing the future of the chase season sure beats going out carousing or engaging in otherwise unproductive behavior! Keep us in the loop if that hi res ECMWF starts to really lock on to a trend of western troughiness (is that a word!?).