Fall Speculation 2018

[AMZ8990]

Alright guys/gals.  Here is our Fall speculation thread.  We decided to create this thread so we can keep the winter spec thread on winter topics.  On a fall note,  looks like the next 5 days will be at or above average temps wise, but by day 6 we start getting some cooler temps incoming.  I for one hope the cooler weather continues to push into our forum.  I’m ready for some fall weather.

[Carvers Gap]

Thanks!  I will put My Weeklies updates here.  I think this will be easier.  

[AMZ8990]

27 minutes ago, Carvers Gap said:

Thanks!  I will put My Weeklies updates here.  I think this will be easier.  

No Problem Carver, I look forward to your update.  I tried to edit the winTer thread to take fall out of the heading but it would not let me edit the thread Title.    I Hope it’s not too confusing for everybody.

[Carvers Gap]

1 hour ago, AMZ8990 said:

No Problem Carver, I look forward to your update.  I tried to edit the winTer thread to take fall out of the heading but it would not let me edit the thread Title.    I Hope it’s not too confusing for everybody.

If you haven't tried it, click on the very first post of the thread and it "should" let you change the title.  I will tag @Mr Bob and see if he can help.  (Mr. Bob, we are just cleaning up some threads by separating fall from winter.  Maybe we can pin both the fall and winter threads?)  AMZ...if you can fix it, I will just delete the post.  

Edit:  Thread title fixed.  Just need it pinned please.

[jaxjagman]

34 minutes ago, AMZ8990 said:

No Problem Carver, I look forward to your update.  I tried to edit the winTer thread to take fall out of the heading but it would not let me edit the thread Title.    I Hope it’s not too confusing for everybody.

You should be able to edit the topic by doing it on your first original post that you started the topic with

[AMZ8990]

1 hour ago, Carvers Gap said:

If you haven't tried it, click on the very first post of the thread and it "should" let you change the title.  I will tag @Mr Bob and see if he can help.  (Mr. Bob, we are just cleaning up some threads by separating fall from winter.  Maybe we can pin both the fall and winter threads?)  AMZ...if you can fix it, I will just delete the post.  

Got it, thanks for the help buddy.  I’ve been trying to figure that out for the longest. lol

[AMZ8990]

41 minutes ago, jaxjagman said:

You should be able to edit the topic by doing it on your first original post that you started the topic with

Thanks Jax,  got it fixed now. 

[Carvers Gap]

9 minutes ago, AMZ8990 said:

Got it, thanks for the help buddy.  I’ve been trying to figure that out for the longest. lol

Thanks.  I have to re-learn it often.  Good work today!  Much appreciated.  On a weather note, the Weeklies(as Jeff noted) from Monday were cooler than previous runs though not necessarily BN.  Just better than the indefinite monster ridge.  We will get a brief respite from the heat due to Florence and then a few more weeks of heat.  Maybe the end is in sight.

[Holston_River_Rambler]

 Operational GFS, GEFS, EPS (39/50 members), GEPS showing a breakdown of Ridge o' Doom by late month. Still a ways off, but...let there be hope!

Maybe the long awaited retrograde finally happens. 

[Carvers Gap]

At +7.8 at KTRI, September has certainly lived-up to the AN to much AN discussion that was had earlier on the forum.  Right now KTRI's average high is 89.5 - in September.  That rivals July and August during many years.  Now the good thing is the Euro weeklies are slowly backing down from the perpetual summer.  Looks like a decent shot of cooler air during week 3 or 4.  By week 6, right back to the oven.  Though the term "oven" is relative as October's norms are cooler than now.  Still I will take a two week respite from this.  Looks like the Weeklies want to move to a pattern where the cold dumps west and then spread east after week 3 w periods of AN/much AN in between cold fronts.   Not great, but 100x better than now.  So, looks like sort of a light at the end of the tunnel w about 3-4 more weeks of much above to above normal temps.  Thankfully, Florence will give us some rain which will cool temps for 2-3 days.  KTRI's temps are warmer than KTYS or Chattanooga's which seems a bit suspect to me - maybe less precip?

[nrgjeff]

Looks very warm early next week even after weekend showers. Front late next week lacks fall conviction; but, it should take out the 70s dewpoints and usher in somewhat more reasonable 60s Tds (after a day or two 50s I-40 north). Might have to wait until October for 50s Tds to hang around.

First stout front on the weeklies appears the first week of Oct. However even it may have trouble clearing our region into the Southeast. +PNA probably favors Plains cool still over the Southeast. We are not approaching winter wavelengths because of both the calendar (any year) and lingering summer pattern (this year). Antmasiello (HM) Tweets a road map to cool Southeast based on an alternate interpretation of Mangkhut remnants and the Pac jet extension; however, it is just a scenario. Personally I favor continued warmth toward mid-Oct. However it should be much more variable with the season; and, we might have days a stationary front bisects Tenn. Yuck!

Weekly clusters still have have majority warm clusters, or at least large minority warm clusters, weeks 3-6. Also see lots of +NAO clusters. I'm afraid most of October could be warm. It will be comfortable either way but...

For winter lovers, hopefully late October offers the flip cold. Yeah, I'll take some severe too, with any transition. Winter Spec thread science got derailed temporarily for a few posts on linguistics. Thankfully it is back on track now. Yes, November often foreshadows the rest of winter with a decent/strong correlation. I would not call it make or break, but November is very important - even El Nino years where hopes are back loaded. So, winter lovers hope for a cold flip in Oct.

Closing on Fall Topic, while I am leaning warm October I would not mind if Anthony is right instead. Hoping for cold fronts, but leaning continued warm...

[jaxjagman]

19 hours ago, nrgjeff said:

Looks very warm early next week even after weekend showers. Front late next week lacks fall conviction; but, it should take out the 70s dewpoints and usher in somewhat more reasonable 60s Tds (after a day or two 50s I-40 north). Might have to wait until October for 50s Tds to hang around.

First stout front on the weeklies appears the first week of Oct. However even it may have trouble clearing our region into the Southeast. +PNA probably favors Plains cool still over the Southeast. We are not approaching winter wavelengths because of both the calendar (any year) and lingering summer pattern (this year). Antmasiello (HM) Tweets a road map to cool Southeast based on an alternate interpretation of Mangkhut remnants and the Pac jet extension; however, it is just a scenario. Personally I favor continued warmth toward mid-Oct. However it should be much more variable with the season; and, we might have days a stationary front bisects Tenn. Yuck!

Weekly clusters still have have majority warm clusters, or at least large minority warm clusters, weeks 3-6. Also see lots of +NAO clusters. I'm afraid most of October could be warm. It will be comfortable either way but...

For winter lovers, hopefully late October offers the flip cold. Yeah, I'll take some severe too, with any transition. Winter Spec thread science got derailed temporarily for a few posts on linguistics. Thankfully it is back on track now. Yes, November often foreshadows the rest of winter with a decent/strong correlation. I would not call it make or break, but November is very important - even El Nino years where hopes are back loaded. So, winter lovers hope for a cold flip in Oct.

Closing on Fall Topic, while I am leaning warm October I would not mind if Anthony is right instead. Hoping for cold fronts, but leaning continued warm...

Euro has a re-curving phoon,middle of next week.So like you said could be a half way decent trough/CF into the first week of the month .

In other news our high tomorrow is 94 here,record is 97.When i woke up this morning i caught the weather on News2 here and they showed a heat index of 104,island heat working in Nashville.

[AMZ8990]

The heat wave in West Tn looks like it has finally made it full circle.  Could still be a hot day or two going forward but the next 10 days look to be around average for this time of year temp wise.  Week 2 could get interesting though as the CPC is talking about an amplified upper level trough is possibly gonna have an affect on some things, possibly some really cold temps in that week 2 timeframe for the upper Mississippi valley.  It’s nice to have some different things going on now to break up the monotony train we were in before.

[AMZ8990]

I guess everybody’s gone on vacation, it’s awful quiet around here.  Too quiet!

[Carvers Gap]

Yeah, I think the board being down and a near record-warm September are just bad for business.  LOL.  Seriously, this September has been warmer than August at TRI!  We had a 74.8 degree average(of highs and lows) for August.  Through September 22nd, we are now at 76.8 and and impressive 8.1 degrees above normal for the month.    The average high has been 87.1.  The hottest day for August was 91.  For September it has been 93.  Eight of the first nine days of September saw 90 degrees or better.  All but two of the first twenty-two days were above eighty degrees.  Ten days have hit the 90 degree mark.  It will be interesting to see where the month falls in terms of ranking.  The Weeklies from Thursday do provide a path back to seasonal once to week 4.  They also provide the first true fall cold fronts which "may" push through during weeks 3/4.  But this ridge really does not want to budge.  Even with BN temps centering more east of the Rockies during the last half of the Weeklies run...the ridge in the SE tries to hold (off the top of my head).  It is going to take some time to break down what is a very stable and very abnormally warm pattern.  This has been a true fall torch.

[Holston_River_Rambler]

Desperation has set in for cooler weather. I'll share this to see what y'all think. Kind of aligns with what we have been saying, but as Flash points out, Typhoons can shake things up either way. Cranky isn't always right, but I really like his discussions of the overall flow in this type of map (cropped only parts that have to do with us):

Maybe I'm just getting too desperate.

Source:http://www.stormhamster.com/entry/e092418.htm 

[Carvers Gap]

Nice run of the Euro Weeklies and as they old Family Feud saying goes, "And the survey says....?"

-Potential pattern change now advertised on tonight's run.  The monster Eastern ridge is on the clock.  By week 3, it "should" be seriously in trouble.  

-A series of cold fronts will slowly beat down the mega ridge.  As noted just above in Rambler’s post, the first of which might not be too far off, but it is temporary as the ridge pushes back.  Classic Fall back and forth fight over the Southeast potentially upcoming.

-Eventually a +PNA will build and dump cooler temps into the East during weeks 3-5.  Week 6 is a bit washed out as it could see a resurgence again of warm air...but that one could go either way.

-Will update later as the different pieces of the run finish. @nrgjeff, definitely would welcome your perspective as it is alway rigorous.  

[AMZ8990]

2 hours ago, Carvers Gap said:

Nice run of the Euro Weeklies and as they old Family Feud saying goes, "And the survey says....?"

-Potential pattern change now advertised on tonight's run.  The monster Eastern ridge is on the clock.  By week 3, it "should" be seriously in trouble.  

-A series of cold fronts will slowly beat down the mega ridge.  As noted just above in Rambler’s post, the first of which might not be too far off, but it is temporary as the ridge pushes back.  Classic Fall back and forth fight over the Southeast potentially upcoming.

-Eventually a +PNA will build and dump cooler temps into the East during weeks 3-5.  Week 6 is a bit washed out as it could see a resurgence again of warm air...but that one could go either way.

-Will update later as the different pieces of the run finish. @nrgjeff, definitely would welcome your perspective as it is alway rigorous.  

Nice run for the dakotas if you like snow!  Glad to see we have a possible shift with the ridge of death we’ve been dealing with.  I think we’re all tired of dealing with those hot temps.  I’ve got a few days ahead with dew points of in the 70’s but other than those few days the overall outlook looks better.  Looks like one of those cold fronts late in the run tries to dip down into Oklahoma and the panhandle of Texas, could be something to watch as it may lead to a chance at some BN temps in the near future.

[Carvers Gap]

This abnormally very warm weather has put a damper on what normally is a semi-interesting Fall thread.  The Euro Weeklies this evening depict some seasonal to BN temps for weeks 3-4 with moderation afterwards and even a resurgence of the eastern ridge for November.  All of that needs to be taken with a grain of salt as shoulder season(usual caveat here) makes those Weeklies exceptionally vulnerable to wild swings.  Still, this run was quite similar to the last run.  The massive eastern ridge will get knocked out of the way, and then attempt to rebound.  It has been incredibly stubborn to move, and will take some work to finally get it out of the way if at all.  That said, I would not be surprised to see it be a bit of a thorn for winter lovers during this winter.  For whatever reason, there really wants to be a signifiant ridge over the SE.  Right now, we can expect no help from the Atlantic in terms of an -NAO.  I know many like to wait for that feature so we don't use-up our mojo too early.  However, the -NAO tends to run in cycles, and it would be nice to see some semblance of AN heights over the next two months.  Otherwise, I am wondering if the NAO might be a problem.  The QBO is beginning to rise(though still deeply negative), but it has a tendency to flip quick which I suspect it will do.  As the negative phase correlates somewhat to a -NAO, the flip positive(or even a rising QBO about to flip) might mean that we have to depend on the PNA and/or EPO for winter weather.  Overall, very warm week coming up and warmth as well next week...then we see some typical back-and-forth fall weather which may be a bit of a shock after the record warmth.   

Cliff notes:  Much above normal --> BN/normal --> slightly AN

[John1122]

We can do well without the -NAO across the whole valley, especially those from the Plateau and westward. The +NAO a few years ago was completely overwhelmed by a favorable Pacific. It was a jackpot winter for those along and north of I-40. Areas in NW Tennessee, North of Nashville, Knoxville North, all the way to the Tri-Cities and points north were generally hit with lots of wintry weather, ice and snow.

Do not want the warm November as I posted about in the winter weather thread. Not a winter killer but it's a hard punch in the first round. 

Pretty much to me I want the EPO to be favorable, then the PNA, and NAO/AO. We have a very very very hard time overcoming an unfavorable Pacific. The NAO can make for the huge storms, especially the ones that effect the far eastern 1/3rd of the Valley region and the Carolinas.

[Carvers Gap]

9 hours ago, John1122 said:

We can do well without the -NAO across the whole valley, especially those from the Plateau and westward. The +NAO a few years ago was completely overwhelmed by a favorable Pacific. It was a jackpot winter for those along and north of I-40. Areas in NW Tennessee, North of Nashville, Knoxville North, all the way to the Tri-Cities and points north were generally hit with lots of wintry weather, ice and snow.

Do not want the warm November as I posted about in the winter weather thread. Not a winter killer but it's a hard punch in the first round. 

Pretty much to me I want the EPO to be favorable, then the PNA, and NAO/AO. We have a very very very hard time overcoming an unfavorable Pacific. The NAO can make for the huge storms, especially the ones that effect the far eastern 1/3rd of the Valley region and the Carolinas.

The Euro Weeklies want to push the trough east, and then have it draw back to the nation's mid-section.  Now, I am not sure how this pattern would present itself during winter...and I suspect the "new pattern might last into early winter."  However, if the pattern changes in mid-October then it does leave room for another pattern change as winter begins.   I generally give a pattern about 4-6 weeks before it breaks.   That does not always work, but just a rule of thumb that I use.  I am not totally convinced that the pattern is warm for weeks 4-6...it may just be a back-and-forth pattern that gets washed out - meaning what happens after the trough heads east is unresolved w the model.  At 4-6 weeks, I can easily understand that....long way off.

The sharp drop in the NAO often signals a storm or switch to cold/stormy for us in NE TN.  It doesn't even have to stay negative for long periods.  Even during long periods of positive NAOs, the NAO often tipped the hand of an upcoming change.  Using last spring as an example, a -NAO is normally a great indicator of cold in eastern valley.  The bigger thing that the -NAO does is to slow down storms, and allows them to turn.  I have said many times that in NE TN, we can get "throwback" snow from the Atlantic which is a micro-climate thing here...the -NAO is a good signal for that.  But even without big coastals which have been far and few between, the -NAO dipping(or rising) is a good signal.  As for the Pacific, it is nice to have it in our favor mainly because it happens more frequently.  However, last winter the Pacific was in our favor (in an extreme way) and we got next to nothing.  I do agree that the Pacific is a good card to have and more reliable in this age of the NAO staying neutral to positive during winter.  I think there are ways to for it "not to snow" no matter how good the Pacific or Atlantic are.  Our latitude, proximity to warm GOM waters, and elevation(speaking of the valleys) are three cards that constantly battle against low elevation snows.  

 

[John1122]

I agree, last year the Pacific was too much a monster, still the storm track got shoved south and the deep south had a snow bonanza. That will occasionally happen but more frequently we'd have been under the gun for winter precip across the entire valley. 

I really hope we can get the pattern to swing in our favor by November, that doesn't guarantee a great winter here but it ups the odds somewhat. I also prefer crisp fall days, like I'm sure we all do. It's tough to sweat it out all summer and have it never let up the first month of fall.

[Save the itchy algae!]

Can we have a graphical geography lesson on what counts as eastern valley/west valley/south valley/north valley/etc? I am not from the area so it all just seems like the valley to me, but it's clear that there are certain microclimates that exist everywhere.  As an example, it seems where I live (Farragut) is generally drier than other places not far away (like Powell).  Can someone knowledgeable on the matters educate me? This might be a good thread topic as I'm sure there are others interested in the geography and how it plays out in tendencies relative to other places...

Second summer sucks.

[Carvers Gap]

1 hour ago, Save the itchy algae! said:

Can we have a graphical geography lesson on what counts as eastern valley/west valley/south valley/north valley/etc? I am not from the area so it all just seems like the valley to me, but it's clear that there are certain microclimates that exist everywhere.  As an example, it seems where I live (Farragut) is generally drier than other places not far away (like Powell).  Can someone knowledgeable on the matters educate me? This might be a good thread topic as I'm sure there are others interested in the geography and how it plays out in tendencies relative to other places...

Second summer sucks.

That is a can of worms...lol.  It depends on who is making those comments.  MRX would refer to the southern valley as Chattanooga.  However, since our forum stretches through TN, the northern Gulf states and southern KY(heck, we have some people in eastern Arkansas that have adopted this region - which is great!)...The eastern valley is the portion of the TN River in the eastern half of the state.  The western valley is the portion that goes through west TN.  Not sure what we call the valley areas in Alabama.  Now sometimes, I refer to the eastern half of the eastern valley as...the eastern valley.  I am on the western side of the eastern valley.  So, maybe I should be more consistent.  As for microclimates... I think the areas on the western slopes of the eastern valley have a tendency to get a rain shadow unless the system is throwing back moisture from a coastal plain low pressure.  In the case of the coastal low, we get some good upslope.  Like Chattonooga, I think TRI actually can get hit w a rain shadow from multiple directions.  That is great for decreasing tornado risks, but kind of stinks for those who like snow.  Now, we get more snow up here due to latitude and the snow squalls from the Great Lakes which is kind of cool. Some areas in the mountains such as Camp Creek deal with mountain wave events and deal w incredibly high wind events...sometimes those even damage their equipment.  I lived off Paper Mill for many years during the 90s...the deeper in the valley one gets, the less snow.  Farragut is almost right on the river.  It is just a ridge or two over.  Also, areas just to the north of Knoxville due slightly better w squalls from the Great Lakes.  Those tend to fizzle out the further south that you go.  I am sure our Knoxville folks and @John1122 can elaborate.  John’s area is in a great place for snow.  But yeah, great question.  I am sure our folks in west TN appreciate the clarification.  However, they have had some pretty decent recent winters in the western valley.  That is my long-winded two cents. 

[John1122]

When I say Western Valley and Eastern Valley on here I'm basically referring to Bowling Green to Huntsville approximately as the center line. East of there and it's Eastern Valley, West of there is Western Valley. The North vs South dividing line is I-40 from Nashville to Knoxville but since 40 turns so sharply SW west of Nashville I'd just draw the line due west from Davidson County into Arkansas to refer to north or south. 

Localized names in the Eastern region are Northern Mountains/Southern Mountains, Northern Valley, Central Valley and Southern Valley, Northern and Southern Plateau. These refer to the mountains from Sevier NE, Blount to the GA border, Morristown to Tri to Gate City Va, Morristown to Loudon County is the Central Valley. Southern Valley Athens to Chattanooga NE Alabama. Northern Plateau is Cumberland to Claiborne County and points N or West of that line. Then Southern Plateau are Plateau areas from south of Cumberland to NE Alabama.

In the Nashville area you have the Eastern Highland Rim, the Northern Rim, the Western and Southern rim. You have the greater Nashville Central Basin area. Our Nashville area posters can much better break down all the microclimates of their area. They don't have as many as Eastern areas because Eastern areas range from 500ft in elevation to 6600 feet in elevation over a short space. But there is a huge difference in winter weather there when you are North of 40 vs South of 40. The highland rim also adds to the winter weather in that area. Clarksville is one of the colder lower elevation spots in the state and they usually do well winter weather wise when it can be rainy and even mild in the Eastern valley.

West Tennessee is more uniform in elevation and it's very much lower elevations. Memphis struggles to get any winter weather at all as does Northern Mississippi. Once you rise several counties above Memphis and start getting into NWTN/SW Kentucky in the far NW edge of the valley, you will experience much colder and more wintry precip than the southwestern valley.

That is pretty much how I see things. The western valley and eastern valley see very different engines at times that drive winter events. The Eastern areas get buried at times with coastal snow events, like the Blizzard of 1993. The Western areas get severe winter weather while it rains in the East such as the Great Nashville Blizzard of 1951. Once in a while we get good southern sliders and the whole region gets painted with snow although far NW valley areas tend to do the worst with those. Those are my favorites. 

[Carvers Gap]

Finally...some hope that the heat ridge will be broken, even if just temporarily.  Below is the 48 hour shot from the Euro ensemble.  The other screenshot is the 15 day(yeah...way out there and woefully undependable...but still...a glimmer.  As you can see, no help from the North Atlantic, but the Pacific improves greatly.  Even a little bit of split flow is apparent (if only it was winter).  Now, I think this switch is going to happen.  Timing is never perfect at this range.  It is likely that the models are "jumping the gun" just a bit.  The first cooler air masses may have a tough time driving south of the Ohio river.   However, the GFS and its ensembles(18z at a glance has it...and sporadically prior to this run) are showing some hope.  The cold shot into the northern Rockies during the middle of next week "should" signal the first push of cold air into the US that has the ability to push eastward.  IMO, that is the beginning of a move to more seasonal temps at the worst.  That said, one can see that even when the trough kicks eastward...the ridge is still there but squashed.

@John1122, you were not kidding about the warm evening temps.  Last night's low at TRI was 60.  The normal is 49.  We had lows in the mid 60s last week, and near 70 the week before.  

@*Flash*, how goes it?  What do you see?

@nrgjeff, where have you been, man?  Hope all is well.  Looking forward to your comments, even if just cold water. 

@Save the itchy algae!, great post by John and hope that helps!

[Carvers Gap]

Grabbed this from the SE forum...that is some serious heat.

[Carvers Gap]

Another interesting stat and I think this is correct...we set no new record highs at TRI during September even though the month was a scorcher.  

[John1122]

It wasn't blazing hot, it was just very warm both day and night. I've seen upper 90s in September but the unending upper 80s/mid 60s are what pushed it over the top. September is usually when we see the first cold fronts, no humidity days, crisp blue skies and temps in the 40s a few nights, and the 50s most nights. That just didn't happen. We had the rain that kept the high temps down but lows were still 8-10 degrees above normal.

[Holston_River_Rambler]

GFS (old and new), EURO, CMC, and NAVGEM all show some sort of tropical critter aimed at the SE in the 7 - 10 day time frame as the Ridge O' DOOM(c) starts to slip north and east and realigned from SE to NW. Maybe this ultimately helps change things up? Of course it is in the 7 - 10 day range, so who knows.  Even if it happens, my experience makes me think the 10 days+ window is more likely as these things tend to take longer than models suggest.  Some models say Gulf, some say SE coast, so will be interesting to see how it plays it if it happens. Could end up just being a piddly little tropical low resupplying us with some nice, refreshing tropical air in mid October  .

le sigh