Spring/Summer 2018 Mid to Long Term Discussion.

[jaxjagman]

GFS looks more Euro today with the typhoon.Both the Euro and GFS take the system more west of the guidance pic shown posted,somewhere around Tokyo then riding through Japan ,this path would significantly weaken the storm

[jaxjagman]

Models show Shanshan basically right now going into around Tokyo around the 9th,then getting kicked out of Japan by a trough.This should set the stage for a cold front into the Valley which still looks to be around the 17th give or take a day maybe.After this East Asia looks like a chance to get  broken down from the heat wave they've been going through.

[nrgjeff]

Japan Met Agency is going a little stronger short-term; then, weakens it faster then the JTWC does 9 Aug. Regardless Shanshan stays well below super typhoon strength. Japan flirts with Cat 2. JTWC keeps it Cat 1. Should be good to get a new East trough and the cold front Jax mentions. However I do not expect a major cool down.

Then by August 20 we could be heating up again (briefly) from here to points northeast. That East ridge could once again be centered north, still allowing scattered t-showers in our region. So we have this early week heat, a break, and then a little more later in August I figure. 

Looking to Labor Day is murky with mixed non-model signals and weeklies. Probably safe to go variable close to climo. 

[Carvers Gap]

Weeklies temp update from TR evening...Weeks 1-4 look seasonal and then mid-late Sept looks slightly AN(increasing more and more until the run ends).  Obviously nothing is set in stone.  The Weeklies are entering shoulder season and can bounce around some.  

[jaxjagman]

SOI has taken some big ups and downs recently,probably the most Ninoish it's been in awhile today.Think we could  see in the long range a decent trough going through East Asia like the GEFS is showing today.Then towards the end of the month a trough in the east

 

Date	Tahiti (hPa)	Darwin (hPa)	Daily Contribution	30 day Av. SOI	90 day Av. SOI
10 Aug 2018	1010.20	1013.70	-31.08	0.24	-1.50
9 Aug 2018	1012.24	1013.35	-16.57	1.61	-1.21
8 Aug 2018	1013.91	1012.40	-0.67	1.68	-1.14
7 Aug 2018	1012.14	1012.30	-10.80	1.34	-1.11
6 Aug 2018	1010.69	1013.10	-24.46	1.67	-0.81
5 Aug 2018	1012.05	1012.60	-13.17	2.46	-0.44
4 Aug 2018	1013.34	1012.60	-5.34	2.34	-0.46

[jaxjagman]

Still looks to be a more trough in the east upcoming.Definite pattern change has been going on in East Asia.The jet into that region has been for the longest going through Mongolia and Russia,now its slipping southward.GEFS shows the trough axis  more  into the Yellow Sea into Korea  and has been consistent with this the last few runs extending even into the longer range.SOI today shows no change -30,Nino

[nrgjeff]

Japan is certainly thankful for the pattern change! Closer to home dynamic models want to cool the Mid South next week, but it looks like a passing weather system vs a major change. Could be a brief warming again around the 25th. Broad East trough mentioned above could indeed come in as the months flip or the very end of Aug. Teleconnections, MJO, KW (ENSO thread) line up.

Both sets of weekly charts show a pretty benign weather pattern here. No big heat. They might have too much slight below through Aug. I'd look for more ebb and flow per above. As noted posts above, timing may shift around as we approach the shoulder season. AN later into September is tolerable or even starting to become pleasant depending on humidity.

[jaxjagman]

Typhoon being shown to hit Japan again then head towards East Korea then should get picked up by a trough,So we should see as said above a trough in the east towards the end of the month.

[nrgjeff]

I agree. Cool period next week looks like a different driver, likely MJO. I see an warm/hot 27-29 Aug. Then the typhoon trough right before 1 Sept? Timing of any could shift of course.

Typhoon Soulik forecast to hit Japan in 4-5 days. Japan Met Agency is not nearly as strong as the JTWC. Japan initialized 5 kts weaker and 3 hr later. Japan gradually takes it to Cat 3. JTWC quickly ramps up to Cat 4. Regardless, the latter still drops it to barely a hurricane when it hits Japan. I look for a trough response, but nothing like with a super typhoon.

Before the Soulik trough both weeklies show a warmer 11-15 day period for the end of Aug. CFS is hotter; ECMWF weekly 11-15 days is still warmer than next week (6-10 day) but not as hot as the CFS. Their 11-15 ensembles are similar, GFS hotter than Euro. Later the CFS wants to get back to warmth in Sept. ECMWF weekly does not. 

Possibly the ECMWF is over estimating Soulik. Could the GFS/CFS have a better handle? Y'all know the ECMWF is my favorite, but once in a while the GFS scores a coup. If the Japan Met Agency is right about Soulik I lean toward the warmer CFS by 7-10 Sept. 

Bottom line, I'm good with the mild next week, warm burst 27-29 Aug. Then typhoon induced cool front by 1 Sept. It is around Sept 7 divergence appears. Based on the situation I favor the warm CFS over the mild Euro, indeed a rare situation for me. Regardless, September becomes more comfortable with cooler nights, lower humidity and nice days.

[jaxjagman]

10 hours ago, nrgjeff said:

I agree. Cool period next week looks like a different driver, likely MJO. I see an warm/hot 27-29 Aug. Then the typhoon trough right before 1 Sept? Timing of any could shift of course.

Typhoon Soulik forecast to hit Japan in 4-5 days. Japan Met Agency is not nearly as strong as the JTWC. Japan initialized 5 kts weaker and 3 hr later. Japan gradually takes it to Cat 3. JTWC quickly ramps up to Cat 4. Regardless, the latter still drops it to barely a hurricane when it hits Japan. I look for a trough response, but nothing like with a super typhoon.

Before the Soulik trough both weeklies show a warmer 11-15 day period for the end of Aug. CFS is hotter; ECMWF weekly 11-15 days is still warmer than next week (6-10 day) but not as hot as the CFS. Their 11-15 ensembles are similar, GFS hotter than Euro. Later the CFS wants to get back to warmth in Sept. ECMWF weekly does not. 

Possibly the ECMWF is over estimating Soulik. Could the GFS/CFS have a better handle? Y'all know the ECMWF is my favorite, but once in a while the GFS scores a coup. If the Japan Met Agency is right about Soulik I lean toward the warmer CFS by 7-10 Sept. 

Bottom line, I'm good with the mild next week, warm burst 27-29 Aug. Then typhoon induced cool front by 1 Sept. It is around Sept 7 divergence appears. Based on the situation I favor the warm CFS over the mild Euro, indeed a rare situation for me. Regardless, September becomes more comfortable with cooler nights, lower humidity and nice days.

I agree.System going into China now,typical pump up the heights into Korea/Yellow Sea before the stronger topical system (SOULIK) + trough,interesting though is another typhoon is on it's heels this afternoon.The GFS has been showing this for a few runs now, the Euro seems to picking up on this now.Score one for the GFS?..LOL.The models will most certainly struggle towards the end of the month into Sept

[jaxjagman]

On 8/5/2018 at 9:38 PM, jaxjagman said:

Models show Shanshan basically right now going into around Tokyo around the 9th,then getting kicked out of Japan by a trough.This should set the stage for a cold front into the Valley which still looks to be around the 17th give or take a day maybe.After this East Asia looks like a chance to get  broken down from the heat wave they've been going through.

We did very well with this system.Early this morning(Friday) we had  some good convection which knocked our power off early in the morning and woke me up about 5 this morning,we had a good line come through Mid Tn,about 2" of rain here some part to our NE got over 4" this morning.Cold front still to the North bringing showers but no convection

[weathertree4u]

5 hours ago, jaxjagman said:

We did very well with this system.Early this morning(Friday) we had  some good convection which knocked our power off early in the morning and woke me up about 5 this morning,we had a good line come through Mid Tn,about 2" of rain here some part to our NE got over 4" this morning.Cold front still to the North bringing showers but no convection

Seems it was fairly localized; here north of town near White House, we have gotten hardly a drop the last few days. 

[jaxjagman]

5 hours ago, weathertree4u said:

Seems it was fairly localized; here north of town near White House, we have gotten hardly a drop the last few days. 

Yeah, we've been in the screw zone as well recently.This was by far the best rains we've seen here in months.Wilson Co., east of us in Williamson Co has been in and out of an abnormal drought for quite some time

[jaxjagman]

Soulik is now being shown much further west getting into the Yellow Sea by the Euro then headed into west Korea.Some big differences with Rumbia right now the next storm headed possibly towards Japan?Another CF coming through the Valley the first of the week,if the GFS is right by Thursday morning parts of the Plateau could be seeing maybe lower 50'S,we'lll see

[weathertree4u]

5 hours ago, jaxjagman said:

Soulik is now being shown much further west getting into the Yellow Sea by the Euro then headed into west Korea.Some big differences with Rumbia right now the next storm headed possibly towards Japan?Another CF coming through the Valley the first of the week,if the GFS is right by Thursday morning parts of the Plateau could be seeing maybe lower 50'S,we'lll see

Sounds great to me! Seems like we started with the heat right out of the gate this year and it has hung tough! 

[jaxjagman]

Thursday early morning the 850mb temps could be running below 2/2.5 standard deviation in some parts of the Valley for this time of year,top it off with a NE breeze it could feel like early fall in August

[BlunderStorm]

Ahhh Now that's more like it.

[jaxjagman]

Typhoon being shown getting into the Yellow Sea then going into Korea,not your typical re-curving path and the trough it was being shown to pick it up now looks faster and don't catch it.But we'll see.The SOI  drop of 30 points between Aug 8-10 might suggest a trough in the east, as well the weeklies last update shows a trough around the last of Aug into Sept in the east.Teleconnections would seemingly have no part of any trough.PNA looks strongly negative at this time which would suggest more HP,but this could change.

Besides what might happen the end of the month into Sept.CPC shows the Valley basically with BN temps for week 1-2 of Sept

[nrgjeff]

NOAA seems to favor the ECMWF over the CFS (previous page NWS week 3-4). They could not be in more disagreement today. We'll see if the Euro changes tonight.  

Asia heat ridge does not want to die. It's locked from Mongolia through parts of Siberia into Manchuria. Ridge is steering their typhoons west/left of forecast. 

Let's enjoy the break from heat later this week. Yup, Shanshan helped us per @jaxjagman forecasts. Low dewpoints will be wonderful! However full summer heat/humidity look to return next week. 

If Cimaron (behind Soulik) goes more at Japan and recurves, maybe another front in early Sept. Otherwise the westward track shifts may leave us warm for a couple weeks.

At least with September sun angle and humidity (both lower) warm will be more comfortable. LOL when are we going to talk about the Atlantic tropics?  

[Carvers Gap]

I have to be honest...I am trying to find something interesting about the upcoming pattern.   I have a hunch September is going to be warm.  It seems that the Weeklies have been a tad too cool recently.  Whichever model is warmer...I will take that one.  The first real cold fronts will likely show-up beginning in about four weeks.  

[Carvers Gap]

@nrgjeff  Would it be correct to call the high latitude pattern on tonight's Euro Weeklies a retrograding one.  Looks like a ridge in the GOA pushes west which is followed by a trough followed by another ridge that pops a PNA or EPO ridge? This all happens over the next 6-7 weeks... 

[nrgjeff]

Yes I agree @Carvers Gap it is a slow multi-week ridge regression. The evolution is not unreasonable the way this summer has gone. Starting next week it looks hot in our Region through Labor Day likely beyond. Perhaps around Sept 10 the ridge axis will be far enough west to ease up here. By then the CFS eases up 2m temps and Euro introduces more precip. Makes sense if ridge retrogrades.

Now the drier weather might be good news for leaves, per the Asheville article (obs thread). Of course it is a little early and a little hot. When do we ever get things to break just right? Still I am confident this year will be better than last (such a low bar). I'm hopeful it'll turn out great.

[Carvers Gap]

Just glancing at the Euro ensembles this AM...looks like a fairly stout ridge will build in the East during week 2.  Indeed, as Jeff called it, looks like the GFS scored a bit of a coup on this one.  The GFS does hint that some seasonal temps might return after wk 2, but that might likely fall into its bias as well.  Overall, still a tranquil pattern(code for boring) modeled for the next 2-3 weeks.

[nrgjeff]

I had a lot of help from the Japan Met Agency (previous page). Thank you though.

5 hours ago, Carvers Gap said:

Just glancing at the Euro ensembles this AM...looks like a fairly stout ridge will build in the East during week 2.  Indeed, as Jeff called it, looks like the GFS scored a bit of a coup on this one.  The GFS does hint that some seasonal temps might return after wk 2, but that might likely fall into its bias as well.  Overall, still a tranquil pattern(code for boring) modeled for the next 2-3 weeks.

BOHICA is code for summer coming back, lol! Yeah GFS Op wants to end ridge too quickly. Ensembles all keep it steaming (pun intended) along through day 15. I do still expect it to break up / retrograde a bit toward 10 Sept. Both weeklies ease up every so slightly; CFS on 2m temps, ECMWF more precip.

Hawaii looks to dodge a bullet, but tropical storm conditions are likely/certain on most Islands. Hurricane force winds should gin up through passes and below mountains. So the Cat 5 tracking is Central Pacific this year. 2018-ing LOL

[AMZ8990]

There is a chill in the air this morning, I nearly needed a long sleeve shirt.  I love the smell outside when the temps are starting to get cooler.  It sounds weird but fall has a distinctive smell and I caught a whiff of it and his morning.

[jaxjagman]

Long range will depend on what happens in East Asia once again.But still seems up in the air.GFS has a trough in the long range with a significant re-curving typhoon.Euro looks slightly slower with the typhoon but there is trough still showing the same time as the GFS,and another trough a couple days after that could catch the typhoon.Looks like what Jeff and what the weeklies show though could still seem to be right even with what the Euro shows.cold front around the 10th give or take.If the GFS is right i believe we could see another big cool period unlike the last tropical system that went into the Yellow Sea as during this time the PNA was crashing now the PNA looks more neutral

[nrgjeff]

MJO is forecast to head into phases 8-1 and over on our side of the globe around 10 Sept. Results are good bad and ugly. The ugly is right at the climo peak of Atlantic hurricane season. The bad is models will flip-flop for another week. The good is the Tennessee Valley should indeed cool off. Send the heat back West.

CFS has caught on. Assume the ECWMF weeklies will tonight. We still have to get through this week and next. At least football is starting!

[Carvers Gap]

Indeed, @nrgjeff, that is quite the adjustment on the Weeklies.  Not sure if it is a blip or just returning to its original BN look centered west of the Apps.  Trough slowly works east and then goes BN from wk 4-7 for much of the nation east of the Rockies.  Going to be a warm next 3-4 weeks though.  But good to see the CFS and Euro both get on board w a shift to more fall like temps.  I have not been posting as much because, well...this is a snoozer of a pattern.  Anyway, football starts on Thursday night w a few week zero games last weekend.  That should hold me over until the first frost.  

[Carvers Gap]

Something interesting (credit to the SE forum), the (CPC ensemble)NAO and AO might be trending in a favorable direction around mid-September.  Absolutely, I am NOT saying we get winter wx.  I just wonder if we might be trending towards a cooler fall and that would fit nicely w the Euro Weeklies from Monday(another run tonight).  My question is this:

How much of an impact does the NAO/AO couplet have during September or is it too early for it to move the needle to cooler weather?  I ask because during summer a -NAO can lead to very warm temps over the forum area....seems like September is where it begins to have an impact here where cooler temps might prevail.

...An interesting story, one year TN had a home game w LSU where it turned abnormally cold.  I had a friend up on Hazel Creek(GSMNP) who was fishing that weekend.  If I remember correctly, they about froze because a burn ban in that area was also in effect - meaning no fire to keep warm.

[Carvers Gap]

18 minutes ago, *Flash* said:

I'll try to follow up with a more detailed, analytical response later on, but for now (at work), I will say I prefer the NAO/AO being neutral to positive this stage of the game. Generally, it seems pattern drivers tend to operate within somewhat cyclical intervals ranging from 45-90 days. Factoring latency with a verified CPC ensemble and I agree, things are looking up if you're pro-fall arriving around the equinox. That said, I think it's too early to worry about where the couplet is now with respect to late fall/early winter teleconnections. I know I speak for the majority of the forum when I say I certainly don't want the spring repeating itself where the cool/cold dump is wasted months removed from peak climo. I love a cool fall, but if I'd sacrifice it if it meant we can pattern flip in November and go cold when it counts. Put another way, in my time living in middle TN, it sure seems mild 'early falls' have yielded colder, snowier winters than mild 'late falls'. Granted, this is more of gut/memory comment than anything else.

I don't disagree.  I was a bit surprised at the CPC though.  Not sure (if anything) of what to make of it.  Yeah, that strat split was incredible...and about three weeks too late to help here.  The early season snow is also the kiss of death.  Agree.  We had that here w Sandy and then again a couple of years later.  Tennessee fans couldn't even make it across the mountains to the South Carolina game because of snow.  I do think it is interesting to see the teleconnection hint(maybe prematurely) that the couplet might go negative.  The seasonal models have hinted off-and-on that BN temps might arrive early and hold...that does not necessarily mean winter temps(definitely not at this stage of the game).  However, the seasonal modeling has hinted that a cooler pattern might lead us into winter.  I have been suspect of that all along, but there is some evidence that it might.   @John1122 often mentions the connections between a warm November and a warm winter.  I loosely watch the teleconnections right now for that reason.  If we were to get a cooler air mass dump during October, it might lead to a warm November which is not a good sign.    I just want normal temps.  OTH, if the pattern hits and holds then maybe those seasonal models were onto something after all.

...Probably should have put that in the winter thread, but some of this is more "extended" instead of winter.  I "hope" that we might be entering an era of a bit more blocking over Greenland.  The -NAO during winter seems to be a bit of a unicorn of late.