Central/Western Summer Medium/Long Range Discussions

[Thundersnow12]

And just like that the new 12z data is interesting in the middle of your trip.

 

Funny thing about that is that one of the top QBO-ENSO-PAC-MJO analogs is 1990. There was an outbreak, as you probably know, on 5/15. All hope is not lost. We just need to get this thing moving along in the Tropics (MJO) and stop this nonsense of cold fronts into the Gulf.

 

For our friends in the Midwest, June got really nasty for you folks in 1990 and pretty much most of the summer too.

 

We're going to try to leave the Saturday which would give us one extra day on the back end so if something were to happen that Sunday (the 19th) and come home on the 20th.

[Hoosier]

June of that year was basically set in stone when it was kicked off by easily the most significant event in the OV since 4/3/74 (I think) and until 3/2 last year. 5/31/85 was more of a Great Lakes event around Lake Erie.

June 2, 1990 was one of the more significant OV tornado outbreaks of the 20th century. Not too big in terms of casualties but certainly as far as strong/violent tornadoes.

[andyhb]

June 2, 1990 was one of the more significant OV tornado outbreaks of the 20th century. Not too big in terms of casualties but certainly as far as strong/violent tornadoes.

 

It was lucky those tracks weren't shifted south a bit, it would've put Evansville, Owensboro, Louisville and Cincinnati right in the trailer tracks of the strongest tornadoes in the outbreak.

 

Quite the powerful shortwave that created this...

 

[HM]

Well, 1990 may look good on paper (really good actually) but it still can't tell us if a tornado outbreak is going to happen in June for the Midwest. Having said that, I think general circulation will tend to mimic that year (and a few others) through June. After that point, we may lose the signal and have to change analogs again. Maybe not, we'll see...

I do envision one day we'll have a tornado outbreak or significant tornado probability tool for weeks 2-4. It will be similar to the tropical products that we have now that show probability of development in any given basin due to various tropical waves (e.g. Kelvin Waves) beyond 2 weeks. If we can simulate moisture, temperature and wind trends through week 4 then this can be achieved down the road with a good climatological base.

[andyhb]

Great posts here HM.

[Indystorm]

June 2, 1990 I traveled from south of Dayton Ohio up to Columbia City IN.  I remember how relatively cool and cloudy it was in Dayton that morning.  Had one of my best t storms ever that evening in Columbia City and state police were pulling motorists off of U.S. 30 for shelter at our church basement for a time as we were under a tor warning which did produce around Wolf Lake IN if I remember correctly.  Obviously not as strong as areas near Petersburg, etc. farther south.   But who knows what the MJO might portend for the plains or Midwest later this May or June. 

[wxmeddler]

MJO progression battle in progress: GFS+GEFS vs. Euro. GFS keeps it progressive while the European stalls it out in phase 4.

 

GEFS:

 

Euro:

[andyhb]

The longer range MJO forecasts from the European suite are quite nice looking (obviously the spread increases, but you get the idea).

 

EMON:

 

EMOM:

[jojo762]

According to Reed, both Wednesday and Thursday are "widespread" severe Wx events of course basing off of the NAM as is typical with him. But, going off of the NAM Wednesday looks nice--compared to what we've had recently, which is nothing, but Thursday seems like convective modes might be a little messy. Have to wait and see what the SPC says in the morning.

[andyhb]

According to Reed, both Wednesday and Thursday are "widespread" severe Wx events of course basing off of the NAM as is typical with him. But, going off of the NAM Wednesday looks nice--compared to what we've had recently, which is nothing, but Thursday seems like convective modes might be a little messy. Have to wait and see what the SPC says in the morning.

 

Good luck to Reed on that, that's all I will say.

[jojo762]

Good luck to Reed on that, that's all I will say.

Instability looks good, but its a bit of a wash, because everything else is pretty much trash.

[nwburbschaser]

If we are listening to Reed about potential severe weather then can we talk about the 384hr potential on the GFS or should we just stick with reality?  

[Minnesota Meso]

Lots of speculation going on here, and believe me I don't have any answers either.  But my gut tells me that summer warmth won't reach southern Canada until mid  to late June.  (Last year about this time I said the severe season would be over the Northern Plains  and most likely into southern Canada, as summer time temps would be early for them).

 

This year seems different, looking at the models, it will take a long time for Southern Canada to warm up. I think the Southern Plains chances for a major severe outbreak are fading fast.  If I were planing a chase between May 15th and June 1st, I think I would set up near Omaha Ne and be prepared to go North, East or West from there.  I don't think this will be repeat of June 2010 over MN, but I do think it will be active.

[Ian]

If we are listening to Reed about potential severe weather then can we talk about the 384hr potential on the GFS or should we just stick with reality?  

 

meh.

 

[wxmeddler]

[brettjrob]

GFS/GEFS still ugly as can be out 15 days. GGEM ensembles look more neutral in the medium range, with fairly zonal flow (even some weak western troughing) that could lead to a long series of marginal setups.

[Ian]

GFS/GEFS still ugly as can be out 15 days. GGEM ensembles look more neutral in the medium range, with fairly zonal flow (even some weak western troughing) that could lead to a long series of marginal setups.

Might be time to stop looking for about a week.

[HM]

GFS/GEFS still ugly as can be out 15 days. GGEM ensembles look more neutral in the medium range, with fairly zonal flow (even some weak western troughing) that could lead to a long series of marginal setups.

 

Meh...if you step back for a minute and look at the models again, it's not a bad continuation from last week in terms of the big picture. Yes the smaller details will always be different but the general idea with the long-wave is still there.

 

After the cold shot, we knew the ridge would build in by mid-week next week, shifting any threat north. Models do agree on that. They also all have the Gulf of Alaska Low retrograding to the Aleutians around day 10 which means the next trough about to enter the Pac NW will have to dig a little more (and so on and so on). This works well with the general idea of forcing migrating through phase 4-5, too. The GOA low tends to build heights over Tornado Alley especially / Rockies but that will position more west with time as the N PAC low retrogrades.  

 

The GFS/GEFS have been terrible with the MJO and that could be affecting the post-truncation jet positioning especially. I'm not worried yet but certainly cautious in my wording with regards to severe weather. Tough thing to forecast at any time scale.

[Dsnowx53]

Meh...if you step back for a minute and look at the models again, it's not a bad continuation from last week in terms of the big picture. Yes the smaller details will always be different but the general idea with the long-wave is still there.

 

After the cold shot, we knew the ridge would build in by mid-week next week, shifting any threat north. Models do agree on that. They also all have the Gulf of Alaska Low retrograding to the Aleutians around day 10 which means the next trough about to enter the Pac NW will have to dig a little more (and so on and so on). This works well with the general idea of forcing migrating through phase 4-5, too. The GOA low tends to build heights over Tornado Alley especially / Rockies but that will position more west with time as the N PAC low retrogrades.  

 

The GFS/GEFS have been terrible with the MJO and that could be affecting the post-truncation jet positioning especially. I'm not worried yet but certainly cautious in my wording with regards to severe weather. Tough thing to forecast at any time scale.

 

 

The GEFS out to 384 (haha, I know) actually looks to have an MJO phase 4 type of look with a split flow -- trough in the western states, but a ridge in NW Canada, along with an active PAC jet...the height gradient is quite tight out there. I don't think it's a terrible look and as you said, it seems to be following the MJO progression pretty well. That active PAC jet might be able to provide some shortwaves. 

[HM]

The GEFS out to 384 (haha, I know) actually looks to have an MJO phase 4 type of look with a split flow -- trough in the western states, but a ridge in NW Canada, along with an active PAC jet...the height gradient is quite tight out there. I don't think it's a terrible look and as you said, it seems to be following the MJO progression pretty well. That active PAC jet might be able to provide some shortwaves. 

 

Well, I think that has to do with the disagreement among the individual members on s/w timing/positioning. In a progressive / poleward-retreating westerlies regime, the ensemble mean anomalies are going to look very broad and unusual. The phase 4-5 impact will happen sooner than 384h, as you know. I'm not sold that the GEFS MJO forecast is more correct and that this MJO wave shoots into phase 6-7 etc coherently.

 

 

I could see the AAM anomalies propagate poleward by 10 days and the stratospheric PV situation completely shutting down in full over the polar regions. This may be the time the westerlies stop retreating and begin to expand away from the poles again. A -NAO developing is also possible toward the 20th (or beyond). Should be interesting to see how this plays out. I agree that at that moment when we've reached max poleward westerlies' retreat, the gradient / jet will strengthen. Could be cool if that harnesses some threats once it comes back southward.

[Ian]

My main good vibe from the LR op gfs is it changes every run in the extended which is usually a sign of some sort of shift. 

[Ian]

Seems like Europe is doing well at least.

[LocoAko]

http://www.pmarshwx.com/blog/2013/05/07/which-is-more-rare-the-current-tornado-drought-or-the-2011-2012-tornado-surplus/

[Ian]

http://www.pmarshwx.com/blog/2013/05/07/which-is-more-rare-the-current-tornado-drought-or-the-2011-2012-tornado-surplus/

 

he's a lot smarter than me but the figures of once in 20-50k years seem a bit "academic" and overdone. still quite interesting.

[Ian]

18z gfs is always my favorite run of the day. waking up to a death ridge is never as fun.

[wxmeddler]

18z gfs is always my favorite run of the day. waking up to a death ridge is never as fun.

 

That polar vortex break down is, as Josh would say, "hawt".

[Thundersnow12]

We're officially leaving Saturday with our last possible chase day Sunday the 19th. Moved it back one day so fingers crossed.

[nwburbschaser]

I'm not trying to put too much stock into the long range GFS, but I'm glad that the 00z is a step in the right direction compared to the 12z.  At this point I just want to see potential in the long range to ease my mind going into these last 10 days before my trip. 

[HM]

I can't remember the last time I saw such a zonal flow pattern on the ECMWF beyond 7 days. Usually, the op euro tends to be too amplified.

 

Quick-hitting s/w type of pattern with occasional EML advection setting up?

[Ian]

I can't remember the last time I saw such a zonal flow pattern on the ECMWF beyond 7 days. Usually, the op euro tends to be too amplified.

 

Quick-hitting s/w type of pattern with occasional EML advection setting up?

 

not really ideal with some 500 ridging mainly over the mtns but probably still works by late May for activity in the high plains at least at times with any little ripple. tho probably better to have a zonal look at range than some sort of highly convoluted blocky crap or something.  still seems to be a tendancy for lower than normal heights in the NE or the Gulf area .. tho the GFS has been showing little trouble with moisture as we head into later May. capping might be a problem tho.