Central/Western Summer Medium/Long Range Discussions

[andyhb]

Euro continues to lift the cut off low north and by 168 it has a decent severe setup (at least synoptically) for the Plains with meaningful leeside cyclogenesis, a 35-40 kt southerly LLJ and a nice, low amplitude shortwave trough.

 

The Global upper air flow pattern also becomes quite strongly amplified on the Euro.

[HM]

This is a great image from Mike Ventrice's website:

http://www.atmos.albany.edu/student/ventrice/real_time/maps/waves/global/28.gif

It shows you the total VP anomaly picture at 200mb in the top image and then the forces that make up the anomalies below it. You can clearly see a classic phase 1 MJO progression through the eastern Pacific with a leading Kelvin Wave across the IO.

Here is a GFS forecast of VP anomalies at 200mb:

http://www.atmos.albany.edu/student/ventrice/real_time/timeLon/vp200.GFS.anom.MJO.5S-5N.png

When these MJO waves reach, say 90E, this is usually when the pattern becomes more favorable for the Plains (it isn't as easy as I'm making it out here but just something quick to look for). So, clearly we have to be patient. The kelvin wave in the IO currently can mimic the MJO forcing to some extent but I suspect its influence to be trumped overall in this setup *(likely absorbing into the low-pass signal of stagnant forcing in W. Pac).

The MJO favors the PNA spike / cold conditions being modeled as it treks into the African-IO sector. I didn't see an updated EURO weekly forecast for the MJO but it seems like the GFS/EC family was still in a disagreement beyond a week (as usual).

[HM]

 

Bogus seems like a good description, at least from the little I have seen from it. A classic case of confirmation bias based on some of the maps used to claim correlation from one event to the next. Complete busts are also tossed and ignored. There is probably a legit reason why there is no peer reviewed literature on it even though the hypothesis has existed for many years.

 

lol. I agree with you here, definitely. I appreciate out-of-the-box thinking but this is nothing but a bunch of nonsense.

 

Always love your mid-long range thoughts. Staying optimistic for our trip.

Thanks. You'll get the cutoff low under the blocking to develop just before your trip. The ECMWF seemed a bit phase-happy/amplified last night from day 6-10 and an outlier against the ensemble mean and other models. As we've seen over the last week with models handling cutoff lows, we shouldn't expect anything accurate with this one either until close range.

[HM]

 

Euro continues to lift the cut off low north and by 168 it has a decent severe setup (at least synoptically) for the Plains with meaningful leeside cyclogenesis, a 35-40 kt southerly LLJ and a nice, low amplitude shortwave trough.

 

The Global upper air flow pattern also becomes quite strongly amplified on the Euro.

Yes and this could be related to the faster, propagating MJO being modeled. The other global models were not as enthusiastic about that happening. I haven't seen the weeklies yet. The images still were from 4/26 the last I checked.

[Ian]

My positive takeaway from the LR is that it seems to be shifting run to run which means at least the pattern won't be totally stagnant hopefully.

[Thundersnow12]

Just give me decent flow into TX with the STJ and I'll be happy or these slow moving ULL's. I'll take another 5/18/10 please. Great supercells with upper 50's near 60 dews up the Caprock.

 

 

 

 

 

 

 

 

 

[HM]

It's doable; it's certainly a possibility. There is a poleward "migration" of AAM anomalies in play:

http://www.esrl.noaa.gov/psd/map/images/reanalysis/aam_total/glaam.sig1-21.90day.gif

The +AAM anomaly should reach 30-40N 5/6-5/10 period. This is at the same time the stratosphere should successfully break down at the North Pole, replacing the vortex with an anticyclone. Stratospheric trends point to a tropopause / lower stratospheric +u anomaly developing also at 30-40N with a -u anomaly at 60N. This works nicely with the poleward AAM in the troposphere / tropical forcing picture.

I don't know if it will be as extreme as the post-truncation 12z GFS run today (it seems off its rocker) but an enhancement of the southern stream seems more likely.

12z GGEM trended toward the ECMWF, by the way, of a quicker solution. It sends a couple of pieces out 5/7-5/10 creating possibly a widespread severe threat. GFS, of course, held with a slower / more blocked scenario. I'm sure you are hoping for a GFS type of timing.

[MidwestChaser]

Is HM Henry Margusity?

[Chicago Storm]

Euro continues to lift the cut off low north and by 168 it has a decent severe setup (at least synoptically) for the Plains with meaningful leeside cyclogenesis, a 35-40 kt southerly LLJ and a nice, low amplitude shortwave trough.

 

The Global upper air flow pattern also becomes quite strongly amplified on the Euro.

The upcoming cutoff limits/delays moisture return. So verbatim that run is a whole lot of nothing.

[andyhb]

Is HM Henry Margusity?

 

Definitely not.

 

The upcoming cutoff limits/delays moisture return. So verbatim that run is a whole lot of nothing.

 

I didn't get a chance to fully peruse Wundermaps or what not last night, but that isn't very surprising.

[Ian]

12z euro has more snow in the Denver to northern plains area next week near the end of the run. Stupid neverending winter.

[brettjrob]

30/18z NAM: teens in the TX Panhandle by Friday morning, 20s down to El Paso and Midland.

[andyhb]

30/18z NAM: teens in the TX Panhandle by Friday morning, 20s down to El Paso and Midland.

 

This can go in the Short Range/Obs. thread that Sam made.

[Thundersnow12]

Finally FWIW the GFS shows promise with a good run out to 16 days with several good looking days near mid month.

 

I'd take that in a heartbeat.

[Ian]

Ha was just about to post that. Right before we leave. hopefully it locks in.

[Thundersnow12]

Ha was just about to post that. Right before we leave. hopefully it locks in.

 

Let's hope. We leave the 10th.

[andyhb]

Finally FWIW the GFS shows promise with a good run out to 16 days with several good looking days near mid month.

 

I'd take that in a heartbeat.

 

Some crazy instability there post truncation especially near the end of the run (Even for May).

[Ian]

Let's hope. We leave the 10th.

I still think we can salvage the yr at least chasing wise if not huge numbers. All that recent moisture will be helpful at some pt just a matter of when and how long/much IMO. There are a number of years that peaked late of course.

[brettjrob]

I still think we can salvage the yr at least chasing wise if not huge numbers. All that recent moisture will be helpful at some pt just a matter of when and how long/much IMO. There are a number of years that peaked late of course.

 

I feel guilty even acknowledging something that's literally at h384 now on a single run, but for the sake of discussion... *if* the switch were to flip on around 5/15, there'd still be time to turn the current perception of 2013 on its head, chasing wise. No doubt this has been the worst March-April combo I've witnessed, though, so it's a tall order.

[MidwestChaser]

12z GFS still looks good with a trough finally showing up. 

[Ian]

I feel guilty even acknowledging something that's literally at h384 now on a single run, but for the sake of discussion... *if* the switch were to flip on around 5/15, there'd still be time to turn the current perception of 2013 on its head, chasing wise. No doubt this has been the worst March-April combo I've witnessed, though, so it's a tall order.

 

Yeah, hard to bite on one or two runs but the GFS has had more western troughing the last few now.  Ensembles are not quite as gung ho yet but seem to be moving in the right direction overall. The ops are often a bit fast with pattern re-alignments.. who knows. It can't get much worse than now at least.

[brettjrob]

Past couple GFS runs have quickly snapped back to 2013 reality for the entire extended range. Ensemble mean slightly interesting in the 312-348 hr range, but meh.

[ZackH]

Yah, GFS seems to be doing its "lets delay the pattern change a little longer every run" thing... 

[andyhb]

HM, got anything else to pull everyone out of depression?

[Ian]

Ops are often too fast on a pattern realignment. But yeah the last few runs not as nice. At least it doesn't look like any big snowstorms in the mid may period. Baby steps. Euro ens mean is pretty zonal toward the end which prob isn't great but better than a ridge or 30s in TX.

[HM]

 

HM, got anything else to pull everyone out of depression?

 

Check out May 500mb anomalies for a coherent MJO from phase 1-5:

http://raleighwx.americanwx.com/MJO.html

There are some striking similarities to the NWP, especially with the cutoff dropping into the West in phase 2 and then possibly lifting out before being restored. There will always be down periods during a progressive anomaly pattern as various ridges/troughs move through, but at least it isn't a winter-like cutoff scenario.

I have to run but I'll try to post later this afternoon.

[wxmeddler]

At least we have a signal now, albeit changing but still a signal!

[Ian]

At least we have a signal now, albeit changing but still a signal!

 

it's on.. first GFS run into our trip. (well, maybe an hour or two early).

 

 

for now im just looking for shear and moisture. high plains chases are better than OKC outbreaks anyway.  

[HM]

The potential remains there on the 12z GFS in that 5/9-5/11 period. The ECMWF solution last night was not quite the same scenario but the ECMWF may still be adjusting (I'm not sure. It has recently trended toward the GFS with the first cutoff and it was going nuts with the initial kelvin wave too).

I like the look of this setup because it isn't too "perfect" synoptically but has everything in the right place for potential. I'm hoping we kick off mid-May with this.

Will the ridge that follows it become semipermanent or will it continue on as we get closer?

By the way, if the GFS solution for 5/10 is more correct in the end, then that is a heck of a signal per the CPC day 8-14 analog. It was picking up on the 5/10 time frame nicely. But we have a long way to go before we can make that congrats official.

[Ian]

The lead in is different but last yr there were worries the death ridge was locking in for good around this pt.. which wasn't totally unfounded for the season, but it didn't happen that fast. It's still way early for that in general. I'd lean toward it being more transient as depicted at current. Even there you still get some flow over the high plains etc. Just need a small vort or such many days if you have the moisture and shear.

 

There is enough variability in the longer rage on models to think there is room for some shift one way or another as well.