Carvers Gap

Yeah, there have been some wild looking solutions on modeling since the middle of the week last week. Odds are it dumps West like it did last time. LOL. Models seem to really like an eastern trough, only to back off as we get closer. That said, there is a pretty strong signal for very cold air to dump into the Lower 48 yet again this fall - already been significant cold into the northern Rockies. Right now, models are showing a strong amplification of the western ridge nearly into the Arctic on some models. Now, that sometimes allows the cold to buckle right underneath it into Montana and Wyoming. For now, modeling is sending it eastward. Then the fun begins as the pattern seems to hold with a deep eastern trough. The Euro/EPS are pretty much at the time of year where I don't trust them as much. However, what the EPS and operational are doing(and have been doing for a few days...weeklies caught it Thursday) is depicting a blocky pattern which does not want to budge. They did nearly the same thing a couple of weeks ago, only for it to revert to a western trough that buckled into the Rockies. That said, it is impressive what is being depicted nonetheless.

That is some pretty strong, high latitude blocking being shown by the operational Euro and EPS. Catches my attention for sure around the d10 range.

The Weeklies can easily fool me at this time of the year...but that is some crazy blocking in the HB and Greenland area at times during that run. Looks like the eastern trough amplifies fairly regularly with a few bouts of a ridge rolling through, but popping again out West. Jeff, feel free to add or subtract from those brief comments....I always look forward to the "Jeff update" on the Weeklies!

Some beautiful weekend wx upcoming once this tropical system exits. TRI is forecasting highs in the 70s with lows in the 40s. Much different than last Sept where we hit 90+ for roughly 14 days with multiple record highs. We have hit 90 only one time during this Sept. We are four degrees above normal right now, but that number should come down quickly after today.

Yeah, coastal states in the West are getting torched, literally. The recent snows and rain really helped the intermountain West. It was within about 48-72 hours of getting scary bad there. The snow storm put a dent in that danger. Now, does that threat come back in the intermountain West as that ridge rebuilds? IDK - maybe. The good things is that the days are getting shorter and temps at high elevation will start to cool off. For places like California and Oregon, not good at all with very little relief in sight.

We have been fooled once already this season, but the EPS is showing what I consider to be a significant pattern shift over NA with a big ridge holding out West with a low over the Aleutians. Not wasting much time going into the details. Pattern change is now within seven days though. Maybe those CPC maps are on the money. If so, we have MUCH cooler temps on the way and soon.

Worth a read from the MA forum regarding the +QBO in relation to Nina winters which follow a Nino.

CPC maps made today depict BN temps in the 6-10 day, 8-14 day, and 3-4 week experimental forecast ranges. Not often one sees that. I will even settle for seasonal.

Whew! It was warm yesterday. Starting to get flashbacks of last September. Looks like a cool down is on the way for the latter third of the month. That said, we hit 90(or above) fourteen times last September. We have hit it zero times so far during this September at TRI. We may very well hit it today though, but still much improved! Watching cross country runners fight the heat yesterday afternoon....glad I was a spectator and glad there was some shade on the course!!! I have much respect for young people who can traverse a course in that heat and humidity.

Time to wake this place up after a few days nap. Looks like LR models are again signaling a cool-off in the East just after ten days(we know the drill when we hear "ten days"). Anyway, I suspect modeling is on to another shot of BN air entering the Lower 48 in the d10-16 time frame - maybe even a bit earlier. edit: Euro OP has it inside of d10.

Completely missed that last paragraph. My deepest apologies for not seeing that. How is it going Jax? Also, thanks for the consistent ENSO updates.

Hey, I actually like one big storm to take all of the leaves down!!!! LOL. I don't like getting nickel and dimed with leaf work. I like seeing howlers come through and just strip every leaf.

Nah...no jinx. Yeah, noticed those trends yesterday morning. They are very similar to last winter. Models dump cold west after an original false push eastward. But hey, it is not winter and I like seeing anomalous cold in the pattern early. Last September, the entire country was baking during Sept and Oct. Changing wavelengths will shake up the pattern...and those changing wavelengths appear to be occurring a bit early. It is possible that modeling just jumped the gun a bit. Wouldn't be surprised to see the cooler air dump eastward at some point shortly after the head fake time frame.

Rains have definitely increased IMBY. It looks like spring here with all of the green. So far this is the antithesis of September last year. Leaves should look awesome this year.

The seasonal CANSIPS which was released today looks much improved for Dec/Jan at 500. My interpretation is that model is touting a seasonal start to winter and then backing West sometime in early to mid January. Also, I would interpret that a flip to cold begins sometime in mid-late November. The model also implies there may be periodic pushes of cold during January before a full retreat to torch city for February. Very classic Nina pattern. Here is the Dec look which is not half bad with a. nice EPO/PNA ridge(more EPO than PNA for sure):

Honestly, I am game for a nice September and then a warmish Oct through mid-Nov. That might give us a colder start to winter, allow for a thaw, and then maybe steal a cold shot in late Jan/early Feb in the middle of warm wx.

Some pretty strong highs showing up in that time frame as well...1040 on the Euro late in its run in fantasy land. Euro control is quite chilly at 12z as well. Would be a nice contrast to last September for sure!

Just for kicks and giggles...the 18zGFS has temps in the upper 30s over the eastern mountains post 300 after a system runs rolls inland. You know I have though that if a system from the GOM were to catch a cold front coming in around Sept 10th....that would be might cold rain!!!!

Looks like the latest cone has Laura going into central Arkansas and into southwest KY...then turning sharply eastward. I will be glad to see some rain. Might be the ticket to a really nice leaf season in the Smokies with rain now.

Feel free to post as much tropical info as possible. MBY is probably good which is why I haven't posted about it. That said, I am more than willing to read and respond to posts about Laura as your area of the subform seems assured of some impacts if modeling is correct. But you folks in the west end of the forum, have at it! Please post observations and thoughts on the system. You know I am here about every day - I will read it!

Six more days until meteorological summer wraps up in the forum area. I tend to see fall as Sept/Oct/Nov in that(met) manner. We are nearly close enough to begin seeing the first frost chances on the Weeklies runs. August has been tolerable. July may well prove to have been the high water mark in terms of temps as Jeff keenly noted a few weeks ago. Going to be interesting to see where the tropical precip tracks. Andy deficits in precip may be made-up quickly depending on the track. Those with already high totals may set some records that will last for decades!

Great info and I may tag onto some of your thoughts. To echo Jeff, I do like what the LR models are cooking up....anything beats the temps last fall. La Nina's are definitely a plus the further west one goes, and worse towards the EC. That said, I think analog packages have really struggled of late. So, I am beginning to think future winters are going to have a lot of variability within analog packages. Honestly, if I had to amend my upcoming winter ideas at exactly this moment...I might cool them off slightly if the weak La Nina verifies. Might go something like normalish Dec, slightly above Jan, very warm Feb in regards to temps. For now, I will refrain from amending. That said, a normalish Dec and slightly above Jan will get the job done in regards to temps...just don't want BN precip. I would normally place weak La Nina at the top of my preferred ENSO state list followed by weak El Nino....Man, after last winter, I am not sure which ENSO state is better. After watching the IO and the SSTs west of the dateline pretty much eliminate winter, I may be giving those two places more consideration - maybe even top shelf consideration. The MJO has really driven winter of late. I "think" if we can get the equatorial western Pacific to cool marginally (without going to a moderate or strong La Nina), we might have some chances. That region has been causing the MJO to rotate through warm phases during winter. The IO is a part of that cycle as it sent plenty of energy last winter into that region which caused convection. If we could get the ENSO region 4 to cool and/or the IO to reduce the amount of energy it is sending eastward....we might not have the MJO cycling so strongly(and multiple times) into phases 4-6 during winter. I like the weak La Nina being modeled on some LR stuff, if it is west based, because it "might" help us with the MJO. I realize there are about 1,000 other things that can screw things up...but I may take my chances with a weak La Nina. Those winters seem to produce a lot of northern stream energy for NE TN. Weak La Nina winters also have a tendency to produce at least one really severe cold shot during winter, sometimes two. Hey, a great example of something so minor really messing with NA weather is that area of high(might have been low) pressure that just wouldn't move east of the Urals. Someone might remember that more clearly. That little feature absolutely changed the entire hemispheric pattern for the winter. La Nina patterns are tricky. They tend to produce cool early winters. What is tough after that is they tend to flip quite warm...but sometimes the cold returns. I have often been fooled by a great looking late fall and December pattern during La Nina years...and then the winter goes West and never comes back. But I agree, western sections should benefit as La Nina winters produce just enough SER to send the "low road" storm tracks through middle TN. The QBO is a big problem right now as it has not cycled into negative territory strongly and is now potentially signaling yet another double dip into positive at 30mb. It will be interesting to see how that interacts with a weak La Nina. That might be a bad combo off the top of my head.

So, is modeling correcting towards a weaker La Nina. Saw that mentioned as a possibility in the MA winter thread? If so, that is a significant.

Also, I noticed the 12z GFS had a snowstorm in southwest MT and northern WY around hour 200. Edit: That is supported by both the 12z GEFS and EPS.

You know the 12z EPS is pretty close to sending fall's first cool air mass into the East. Probably more likely to drop into the middle of the continent first. However, that is a pretty good blocking signature in d10-15. And yeah, feels pretty good to be saying all of that on August 23rd!!!