Fall Speculation 2018

[Carvers Gap]

@John1122 Nice trends on both the 12z GEFS and EPS fo days 10-15.  Obviously that is way out there, but I was not liking the persistent ridge that both had latched onto.  Now, it seems the trend is to at least be seasonal w the ridge over the northern Rockies.  Hopefully, this is the trend for the next several runs.  This is the second run of the EPS to weaken or remove the SER in the LR.  Maybe they are jumping the gun just a bit, but those two models are at least throwing some shade towards Nino climo.  The Weeklies scoot that aforementioned ridge out pretty quick.  Was hoping Jeff would drop by and add some commentary...He knows the shoulder season tendencies of the Euro and GFS.  It may very well be that the ENSO may flex its muscle soon.  @jaxjagman, what is the most recent ENSO state and projection...wondering if it is now in Nino neutral state?

[jaxjagman]

4 hours ago, Carvers Gap said:

@John1122 Nice trends on both the 12z GEFS and EPS fo days 10-15.  Obviously that is way out there, but I was not liking the persistent ridge that both had latched onto.  Now, it seems the trend is to at least be seasonal w the ridge over the northern Rockies.  Hopefully, this is the trend for the next several runs.  This is the second run of the EPS to weaken or remove the SER in the LR.  Maybe they are jumping the gun just a bit, but those two models are at least throwing some shade towards Nino climo.  The Weeklies scoot that aforementioned ridge out pretty quick.  Was hoping Jeff would drop by and add some commentary...He knows the shoulder season tendencies of the Euro and GFS.  It may very well be that the ENSO may flex its muscle soon.  @jaxjagman, what is the most recent ENSO state and projection...wondering if it is now in Nino neutral state?

Enso today is or looks more warm/neutral.There is some warm waters showing up in the thermocline around 120W,if it makes it to the surface is another thing

[nrgjeff]

I'm baaack! Thank you for asking I'm doing well. Just got slammed at work and had some activities at daughter's school. Funny at work they figure schedule tons of meetings and projects during mild climo. Then it ends up busier than peak weather. 

Finally got the pattern change. I figured mid-Oct. As usual it took a couple fronts to push out the SER. Interesting how Pacific hurricane remains no longer cut across the Plains. Last and next did/will track through Texas east.

Well the CFS and ECMWF weeklies are about as polarized as.. Numerical Weather Prediction NWP, lol! I'm going cool through Halloween. Could get a milder blurb first weekend of Novie, and maybe part of that following work week. Otherwise, pattern seems to want to go back cold. CFS disagrees, perhaps the MJO. However the ECMWF appears to have a better handle on the Kelvin waves. Ask Saipan how that is rolling along with the Cat 5 super typhoon - not good for the US Protectorate. Oh yeah, maybe keep some blocking if not Alaska in northwest Canada. NWP does tend to keep some high latitude blocking, supporting the cooler idea.

If the November 2-5-7 warmth is temporary, perhaps another shot at mild toward Thanksgiving. My only (weak) reasoning is do a mild blurb every couple weeks. More in Winter thread (shortly)..

[Carvers Gap]

The Euro Weeklies tonight do indeed depict a warmish week three w cold returning after that...good call by Jeff and the other folks that said the ridge would not last.  

Looking very far into the future....If it is to be believed, the Weeklies would also place seasonal to BN temps over the forum area to begin December(weeks6-7)...but, again, that is way, way out there.  Since we haven't even reached the end of October, take that with a huge grain of salt when I discuss December.  

Anyway, I think I have reached my word limit for the week between this and the winter thread!!!  BTW, I really enjoyed watching the forum from afar while in Montana.  Great discussion!

Looking forward to this cool weather this weekend...

[John1122]

The AN temps the ensembles were forecasting for the 1st week of November have turned the corner. Good way to start the month if we can reel this in.

[nrgjeff]

ECMWF Euro weeklies performance improved markedly in October, after a couple dismal months. Assuming it is accurate, and not just stuck cool, I believe it over the warmer CFS. The latter has reduced the number of warm weeks.

Euro ensembles and weeklies kind of missed the Halloween warm spell; so, I hope that is not a warning of more poor performance. Weeks 3-4 clusters are all over the place, some opposite patterns. Chaos may continue. However I do not buy wall to wall CFS warmth.

[jaxjagman]

Typhoon Yutu no longer looks like it will re-curve instead the models bring into the Philippines,it went to far south to get picked up by the trough  that  has been showing in East Asia which should effect our weather in several days.So give -/+ days should be around the 6th next month,the PNA is going - during this time frame,so we should see a trough coming east.After this the heights/ridge builds in East Asia for a couple days but then per EPS goes more zonal after that,this don't look like a substantial warming pattern right now upcoming into week two of Nov.,not right now anyways.

[jaxjagman]

Prognostic Discussion for Week 3-4 Temperature and Experimental Precipitation Outlooks 
NWS Climate Prediction Center College Park MD 
300PM EDT Fri Oct 26 2018 

Week 3-4 Forecast Discussion Valid Sat Nov 10 2018-Fri Nov 23 2018 

The outlooks for Weeks 3-4 rely on dynamical model guidance from the NCEP Climate Forecast System (CFS), ECMWF and JMA operational ensemble prediction systems and the Subseasonal Experiment (SubX), an experimental multi-model ensemble (MME) of both operational and experimental dynamical models, as well as statistical model guidance that uses correlations between indices for major modes of climate variability, the Madden-Julian Oscillation (MJO) and El Nino Southern Oscillation (ENSO), and the temperature and precipitation over North America. The potential evolution of climate conditions from forecasts for Week 2 are also considered. The MJO is currently active with convection over the Western Pacific, and dynamical ensemble model forecasts predicting probable propagation across the Western Hemisphere into the Indian Ocean during the next couple weeks. Statistical tools indicate a potential for below normal temperatures over the Western CONUS related to the current state of the MJO. ENSO-neutral conditions are currently present over the tropical Pacific Ocean, with the likely development of El Nino conditions during autumn. Sea surface temperature anomalies over the central and eastern tropical Pacific are currently between +0.5 and +1.0 degrees Celsius. Potential El Nino conditions during Week 3-4 increase the likelihood of above median precipitation across the Southern CONUS and below median precipitation over the Northwest CONUS and Midwest region, as well as increasing the likelihood of above normal temperatures across much of the Northern CONUS from the Northwest into the Northern Plains. 

Dynamical model guidance for Week 3-4 predicts negative 500-hPa height anomalies over western Alaska, the southwestern CONUS, and Greenland. Differences appear between the various dynamical models on the extent of positive 500-hPa height anomalies across Canada and the Eastern CONUS. The ECMWF indicates weak negative 500 hPa height anomalies extending from the Southwest to the Northeast CONUS, while the CFS predicts positive anomalies across the Northern CONUS and most of the Eastern CONUS. The JMA ensemble model and some member models of the SubX predict a strong positive 500-hPa height anomaly over eastern North America, which is discounted in the Week 3-4 outlooks. In addition, differences between member models of the SubX indicate some uncertainty in the predicted circulation pattern for the Week 3-4 period. The Week 3-4 temperature and precipitation outlooks give greater weight to tools relying on the ECMWF ensemble forecast, blends of the CFS and ECMWF forecasts, and some member models of the SubX, including the SubX version of the NCEP Global Ensemble Forecast System (GEFS), that are more consistent with the Week 3-4 outlooks from last week. 

The Week 3-4 temperature outlook indicates increased probabilities of above normal temperatures for all of Alaska, with the greatest probabilities for western Alaska, the Aleutians, the southern Alaska coast, and the Alaska Panhandle, due to anomalously warm sea surface temperatures near these regions and predicted anomalous southerly flow. Increased probabilities of above normal temperatures are also predicted for the U.S. west coast, the Pacific Northwest, the Northern Rockies, and the Northern Plains, supported by a combination of ECMWF and CFS temperature forecasts. The probabilities of above normal temperatures for the Southwest have decreased from the Week 3-4 outlook released last week and from the Week 2 forecast, with predicted below normal 500-hPa heights over the region by most dynamical models. There is an increased likelihood of below normal temperatures for parts of the Southwest, supported by the CFS, ECMWF and SubX forecasts. Above normal temperatures are most likely for the eastern Gulf Coast and southeast Atlantic Coast, supported by dynamical model forecasts, and in particular the SubX. Below normal temperatures are most likely for parts of the Northeast, as indicated by the ECMWF, CFS and GEFS. Above normal temperatures are likely for the Hawaiian Islands, with greater probabilities for the southeastern islands, with predicted persistence of above normal sea surface temperatures. 

The Week 3-4 precipitation outlook indicates increased probabilities of above median precipitation for Southern Alaska, including the Aleutians and the Alaska Panhandle, with a predicted enhanced storm track over the region by all dynamical ensembles. Likely below median precipitation is indicated for much of the west coast and the Northwest CONUS, supported by the CFS, ECMWF and SubX forecasts. An increase in the likelihood of above median precipitation for the Four Corners region, ahead of a predicted trough, is indicated by most dynamical model forecasts, and is consistent with Week 2 precipitation forecasts. Increased probabilities of above median precipitation across much of the Southeast region, from East Texas to the Tennessee Valley and the southern Mid-Atlantic coast, is also indicated by the CFS, ECMWF and SubX MME forecasts, and persistence of the Week 2 precipitation outlook. Below median precipitation is more likely for the western Great Lakes region, as indicated by the CFS and the SubX MME. Above median precipitation is likely for the Hawaiian Islands, with greater probabilities for the southeastern islands, as predicted by the CFS, ECMWF, and SubX MME. 
 

[Carvers Gap]

The Euro Weeklies are out and are just a total mess on the WxBell site.  The main temp profiles for each week are BN w maybe a weak of seasonal.  However, the 46 day temp is well AN.  I have no idea how that is happening, so there is likely a glitch or maybe just the usual user error.  Just no way to get that much BN and have a ridge of warmth over the SE where a trough is and weekly temps that are also BN.  Now, the hindcast/climo based weeklies go warm at 2m for weeks 4-7.  I think some of this is caused by a glitch(46 day not correlating) and some of it is issues w source regions for cold and some of it is zonal flow in a flat ridge/trough...which is likely pumping Pacific air into the lower 48 instead of polar or Arctic air.  No matter what you believe about the next six weeks...the Weeklies tonight are their to support you.  LOL.  Ah...the world of numerical wx models.  The teleconnections that we like(AO, NAO, and EPO) are flat with little influence.  So, maybe an extended period of zonal flow is now a growing possibility later in November and to begin December.  Anyway, the overall pattern looked progressively Nino-ish.  Periods of cool weather, a ridge popping at times over coastal areas, AN precip...lots of cold rain.

[Carvers Gap]

The 0z GEFS and 0z EPS are just about polar opposites w their 2m temps in the LR.  The GEFS is setting ups a trough over Alaska and Greenland-ish.  The EPS basically cools the entire lower 48.  I think either option is possible... Really seems like all options are on the table as we approach mid-November.  

[Carvers Gap]

...That said the EPS is fairly similar at 500 to the GEFS after a quick look.  The trough over Alaska is pesky and teleconnects to warm wx here.   Tough call for November temps.  Cool early, but the last half of the month is tough IMHO.  Going to be some warm...duration and strength TBD.  I wonder if the Weeklies might be out of step w/ weeks 2-3 when compared to operational guidance....not sure, just throwing that out there.

[Carvers Gap]

Watched a bit of JB this AM and he noted the zonal trend as well...now, I am "one foot it" for a good winter, but for those who have been reading my posts, I am not "all-in" for a winter for the ages.  I do sometimes like seeing JB squirm.  His forecast for winter was crazy cold, and borderline unbelievable.  So, zonal flow showing up in the middle of November better be transient or he busts right out of the gate.  Anyway, I think we have some cold to begin November followed by warm zonal and then followed by IDK.  Here are a couple of very similar looks(5 day averages) by the 6z GEFS and 0z EPS.  They are in remarkable agreement over AK w some downstream differences over Canada...but both indicate that a period of zonal flow may indeed develop.  See those heights over the SE?  Those BN heights over Alaska probably signal at least 7-10 days of warmth over the SE for some portion of the middle third of November(edit).  Now, here is some straight cherry-picking on my part...but this pattern does look remarkably similar to the +QBO(betting it is positive when it updates after this month)/low solar look that I shared in the winter thread.  Shallow trough over the eastern half of the country.  Now, is this the predominant pattern for winter?  I don't think so, but it may be a something that could repeat itself.  I just think the ENSO pattern has not fully taken over yet and it is shoulder season, so the main drivers may not be in the front seat yet.  However, if this pattern were to persist into late November...then I think those that chose middle to back loaded winters for their forecasts stand a very good chance of being correct.  That last thought also fits nicely w Nino climatology.   Some of you may be wondering why zonal is a big deal in November(at least in my brain).  I think the winter tends to repeat patterns from November - not always.  Food for thought and certainly not written in stone...

 

[nrgjeff]

Novie is starting to look variable and choppy. Fun forecasting, um not really! Going between the warm CFS and cool ECMWF weeklies is more than a lazy compromise. Per reasoning above the meteorology also supports doing so. Could be a brief cold shot late next week, with more warmth after. Warm Novembers are not deal killers for cold El Nino winters. In fact a few recent Ninos had cold Oct, then warm Nov or Dec, before some cold weeks later in Jan and Feb. 

Since this is the Fall thread, I am seeing some encouraging photos over in Southeast/Mountains. Apparently the leaves are starting to change mid-mountain and Valley. Peaks were garbage. TVA and other social media also showing good stuff starting around Tenn. Saw colorful social posts along the Clinch River below Norris Dam, and at Fall Creek Falls SP.

I wanted to try Frozen Head SP last weekend; but, weather/busy Sat/Sun and now figure it's past. Probably just go local this weekend. Lookout Mountain and Signal Mountain showing signs of change here. Anybody have intel on the Plateau or up near Knoxville?

[Carvers Gap]

Cause you know this always happens when we post maps past day 10....I posted that comparison yesterday...and now there are fairly significant changes in the GEFS, especially 6z and 12z suites.  Large areas of the lower 48 are covered in BN temps.  Also, some changes at high latitude.  As Jeff stated, plenty of back and forth...but that is encouraging.  

[Carvers Gap]

Yeah, as for leaves...I noticed that NE TN is seeing some quick changes at lower elevations now.  Bout time!  Not at peak by any means, but noticeable changes for sure.

[John1122]

My area is at peak above 2000 feet and probably a week from peak below that. The heavy rain tomorrow may end the peak early above 2000.

[Holston_River_Rambler]

Maples are looking brilliant in and around Knox. Oaks, maybe not so much, but they never seem to be colorful.  I grew up near sweet gum trees and miss their colors.  Knoxville maples not quite there, so hopefully this rain will not annihilate what's looking like on of the prettiest leaf shows in a while for me anyway. Heard good reports from Cumberland County, but haven't been there myself.  Driving from Knoxville to Harriman today, the leaves didn't seem as vibrant around I-40 as in my neighborhood near downtown Knox. 

 

[Daniel Boone]

Peak here now. 2 weeks behind schedule.  Amazing how late it is. 

[John1122]

I'd actually say most of the area here is now at peak as well after taking a look around yesterday evening. It's crazy how fast it has moved. The entire process of change has happened in about 10 days.

This is looking down in the 1300-1700 feet range yesterday evening from around 2800 feet. You can see much more color looking down on it.

[BlunderStorm]

As for here a peak is hard to define as all the trees seem to have different ideas but if I had to place it I would say it is probably since Monday til now.

[Carvers Gap]

After a cool weeks 1-2, the Euro Weeklies (the one based on hindsight/ensembles) depicts a zonal pattern for weeks 3-5 before returning to an eastern ridge and western trough around the second week of December.  Nothing huge...the zonal look has been hinted at for a couple of runs.  Still, a long way out there.  Really, it looks like a normal pattern evolution regarding El Nino climatology...warm start -> transition -> maybe cold?

[Carvers Gap]

3 hours ago, John1122 said:

I'd actually say most of the area here is now at peak as well after taking a look around yesterday evening. It's crazy how fast it has moved. The entire process of change has happened in about 10 days.

This is looking down in the 1300-1700 feet range yesterday evening from around 2800 feet. You can see much more color looking down on it.

Beautiful part of the country right there.  Thanks for the photo!  I noticed that things have really taken-off here this week.  Very quick change.  

[AMZ8990]

44 minutes ago, Carvers Gap said:

After a cool weeks 1-2, the Euro Weeklies (the one based on hindsight/ensembles) depicts a zonal pattern for weeks 3-5 before returning to an eastern ridge and western trough around the second week of December.  Nothing huge...the zonal look has been hinted at for a couple of runs.  Still, a long way out there.  Really, it looks like a normal pattern evolution regarding El Nino climatology...warm start -> transition -> maybe cold?

Definitely a possibility for a cool down mid November.  Although I’m sure that will change as we get closer.  Long range still looking pretty good for winter lovers like us though imo.  

[Carvers Gap]

15 minutes ago, AMZ8990 said:

Definitely a possibility for a cool down mid November.  Although I’m sure that will change as we get closer.  Long range still looking pretty good for winter lovers like us though imo.  

I won’t lie...zonal patterns can be quite stable with the cold locked up over the northern latitudes.  Maybe 09-10 is a good example, and we know where that went after that.  Still a couple of weeks before early winter shows it’s first hand...we will know soon.  

[Carvers Gap]

***UPDATE***

So, the "non-hindsight"(no idea what to call those) temps are in, and they are different.  Looks like seasonal temps to slightly BN for weeks 3-4 and weeks 5-6 are warm to end Nov and begin Dec.  Looks like periods of zonal where a trough lifts out and won't hold.  Next shot reloads, and comes in.  Have you ever seen one of those winters where there is plenty of energy but you need good timing?  Though it is not winter, that is what it looks like.  Some -NAO(transient at times) w a -EPO ridge in place as a semi-constant feature.  Very active, changeable pattern with lots of transient shots of cold and warm.  The BN heights that like to crop-up over the SE seem to signal El Nino taking the pattern over.  Anyway, plenty of mixed signals.  One thing to be wary of w the ensembles lately is that the 500 temps have not always been correlating to 2m temps.  Fall is a time of changeable weather, and the upcoming six weeks looks to hold something for everyone...warm, cold, rain, and maybe even the first flakes of snow during late November and early December.  

[John1122]

Looking back on reports about the Euro weeklies from around 4-6  weeks ago, it was also depicting zonal flow towards the end of its run then.  

This looks to be the actual result for the time frame.  

[AMZ8990]

18 hours ago, Carvers Gap said:

I won’t lie...zonal patterns can be quite stable with the cold locked up over the northern latitudes.  Maybe 09-10 is a good example, and we know where that went after that.  Still a couple of weeks before early winter shows it’s first hand...we will know soon.  

Ah Yes,  09-10 winter corresponds well!!  And your right, we will know soon.  Gonna be an interesting month for sure. 

[Carvers Gap]

8 hours ago, John1122 said:

Looking back on reports about the Euro weeklies from around 4-6  weeks ago, it was also depicting zonal flow towards the end of its run then.  

This looks to be the actual result for the time frame.  

It transitioned to a cooler(for early Nov) beginning about a month ago just looking at the comments.   Again, I always say to take the Weeklies w a grain of salt during fall and especially after week 4 at any time of the year.  The Weeklies IMHO have not been great this fall, but they will begin to calibrate a bit better now as we reach winter.  Now, what is showing up now is within the 3-4 week(as opposed to 5-6 week range) range and is also now at LR on the 0z EPS and 6z GEFS.  As noted above, the model is even in conflict a bit with itself (hindsight weeklies vs weeklies without hindsight).  For the past few weeks we have been discussing a cool start to November with some back-and-forth warmth after that w the month potentially going slightly above normal.  During shoulder season, models can easily miss as has been noted.  However, if the below map from the 0z EPS verifies...that is a pretty decent job by the Weeklies to hit the pattern even if it missed the time frame by a few days from that range.  That is the five day 500 average from November 12-17.  

 

[Carvers Gap]

And here is the 6z GEFS 5day average for the same time frame....Time will tell if these verify.  Interestingly, there has been some talk that this type of pattern can precede blocking.

[Carvers Gap]

I should add as well, back-loaded winters are often the calling card of El Nino winters.  The best thing that we have going for us is that we are not in a drought.  El Nino patterns(provided they are not super or strong) generally give us some chances in January and February.  I do think that this month will feature a ton of back-and-forth(after early month) as Jeff noted and as is seen in a number of models.  I also think that November will average slightly AN, but that will depend on how much zonal flow that we actually get...and if we can flip back cold by the end of the month.