Oct.-Nov Pattern Discussion

[valkhorn]

12z GFS and Para GFS don't look bad if you're on the TN/KY border. Nashville may have a better chance for accumulating snow than Knoxville, but it looks like everyone in TN could see a brief change to snow before moisture exits even if it doesn't accumulate.

 

EDIT: Everyone except MAYBE extreme SE TN.

[GaWx]

 Check out the 12Z Euro. It is coming in MUCH colder for the N Plains and Midwest for the 6-10 with a NEW Arctic high that wasn't even there on the 0Z Euro. It has MSP 850 of -12 C at hour 192 vs. 0C on the 0Z. At hour 228, NYC is at -7C at 850. On the 0Z, NYC was +4C.

Could this be the start of a colder modeling trend for late November. It is only one operational run. So, I'm guessing it is a burp for now. However, this is the best model out there and it is a huge shift. So, we'll see.

[tnweathernut]

Talking long term...not short term. I think the hype with this cold is a bit overblown. Flurries and cold in November are not rare here. Again, long term looks zonal and warm - above average. Easy, chief.

The blocking that is occurring now is good to see.  I think it's a pattern that will repeat more than once, especially in Jan and Feb. I agree that flurries and cold in November is not rare, but in JC there has already been a couple of inches to four inches around town (a couple of weeks ago), now more light snow this morning and a ton of wrecks in Unicoi County from a dusting with temps not getting up much above freezing.  If you look at the forecast for next week, -16 at 850 doesn't happen in TN very often in November. We will see if next Tuesday can be one of those times. It's a good bet we don't get above freezing for a high next Tuesday.  There is also the chance at another rain to snow changeover (accumulations not likely) with that system.  I consider all of this very impressive for so early in the year.  I do think social media has a way of making cold events like now and what is coming next week seem overblown though.  It's not like it's the end of the world, and though next weeks blast is even more powerful, it's also transient.

 

I am with Jeff and others................wrt the thinking that multiple days of 15-30 below normal won't likely get erased and turned to above normal through the end of the month, so likely thinking we end November a bit cooler than normal, but not overly so.  It also looks like a good bet we turn warmer.  How much warmer is still up for debate.  It will be interesting to see if the warm up is also transient and how long it takes to re-load the pattern.  As has been mentioned, it wouldn't surprise me to see the bulk of December at or above average in temps, but it also wouldn't surprise me to see the cold come back more quickly either.  Time will tell.

 

[tnweathernut]

After looking more closely at the temp departures, it appears the TN Valley has a pretty healthy negative departure so far this month. I would imagine the next 5 days will really enhance that as well. Would be all but impossible to erase that in the last 10 days of the month.

[tnweathernut]

Here is a picture taken from JB's twitter feed to show temps so far this month.

[Carvers Gap]

I agree this cold spell is pretty stout. I do think this winter will be OK in terms of things to track. I just generally see many of the forecasts as too good to be true. But I don't claim to know any more about the long range than any other WX hobby person. Like Mr. Bob, I see December as a typical Niño pattern. I do think the cold and snow will have their moments and maybe some great ones. I think winter is slightly above for temps and above for snow or average at the very least. But hey, I just enjoy discussing it. That is why I am here. Really like our forum!!!

[jaxjagman]

Don't know about yall.But a 1/2" to us around Nashville is gonna look like a blizzard.To you guys out east its a spit in the bucket,to us someone turned the hose on and filled the bucket up.Our last three winters have sucked,hopefully this is the start of something good

[tnweathernut]

I have a bet going with my buddies in Gallatin. A single storm 6" snow for them and they all buy me a steak. Less than 6" and I buy them one. I am taking a BIG chance since the snow dome over the Nashville area is no joke.:....

On topic.......Pattern after mid next week looks boring.

[jaxjagman]

Amazes me how the GFSP has been so consistent the last 3 or 4 days.Just looking at the anomolies it looks colder than the GFS

[jaxjagman]

The Euro is showing some 90-100 wind shear like the gfs showed a couple nights ago

 

Pretty impressive a couple days before turkey day

[jaxjagman]

 

In the Euros time frame

[jaxjagman]

This weekend system keeps shifting to the west warming the layers up even more

 

 

 

Crapola look

 

[jaxjagman]

lLooks about right to me,there is a piece of energy diving down from the NW after this system exits the models are showing but it's really weak,should allow flurries most of the day Monday for some extra tokens for us in Mid Tn.,maybe if it's right

[jaxjagman]

 

If you get lucky you might get a extra token Monday into early Tuesday morn.,maybe even a brief shower but it looks to fizzle out by the time it gets east of the Ms River

[jaxjagman]

 

Maybe some good signs looking ahead

[John1122]

Good luck in getting any snow flying in Nashvegas Jax. I know it's been tough, but November snow is like late March/April snow, just a bonus. With luck we can keep a favorable look going into January and February when the money time is in full effect.

[jaxjagman]

 

wow

[Carvers Gap]

I like the fact that cold is building over Canada on the 12z Euro.

[valkhorn]

Looks like the very back edge of the precip could have a brief changeover to snow so be on the lookout for that.

 

Also the 12z GFS and Para GFS are putting out a small chance of flakes late next week.

[jaxjagman]

This really should not be a tough forecast, especially when you consider how well the comprehensive analog system has worked since last winter (just one truly bad call, that being for a warmer March 2014). There is a definitive +PDO signal, what with cooler SST anomalies over the interior of the northern Pacific Ocean and very warm deviations off of the shoreline of North America from Alaska down to Baja California. A weak El Nino is setting up, basin wide in nature but serving to enhance tropical forcing more in the Orient and near the International Dateline, in a "Modoki" fashion. Blocking has been prevalent in the -EPO, +PNA, and -AO positions since Labor Day, and the chance for more positive height anomaly formation should regroup over Baffin Island and Hudson Bay in the longer term.

But there is a fly in the ointment, namely the statistical models such as the CFS and ECMWF weeklies and monthlies. Those longer term outlooks can best be described as wall-to-wall warm over the U.S. and Canada, continuing a trend seen since the summer months. Yes, these schemes have been wrong, often embarrassingly so. But the GFS and GGEM ensembles fail to see high-latitude ridging returning in the 11 - 15 day period, making the European equation variants somewhat of a loner. Because there are some predictions that are reluctant to get the U.S. back into the freezer, so to speak, the idea I am going with is that it may take another storm moving from Texas into New England November 29 - December 1, to reset the blocking configuration and chances for widespread cold air intrusions that the nation has gotten used to after Halloween.

As far as December goes, I have not really changed my mind about the temperature and precipitation forecast. I made slight revisions to my analog roster, which now includes 1926, 1952 (twice), 1957, 1960, 1968, 1976 (thrice), 1979, 1985, 1986, 1995, 2002 (thrice), 2004, 2006, 2009 (twice), and 2012. The 500MB longwave pattern in the Northern Hemisphere between November 1 and 10 strongly resembled that of 1952 and 1976. The elongated warmer water display from Alaska southward to the Mexican coast is similar to 1957. The deep snowpack seen across Eurasia and North America is fairly close to that of 1976, when a typhoon injection occurred along the lines of Nuri. What it all boils down to is that the western and north central states may have a run of fair and relatively mild days thanks to strong ridging (+PNA), while an active storm track helps hold readings down along the southern and eastern tiers of the U.S. One consideration with the big blocking signature and a very negative 500MB height anomaly n the Northeast: there is potential in this pattern to get a strong cold shot and a major winter storm of the Nor'easter kind, most likely around the big holiday week.

Let it snow. Let it snow. LET IT SNOW!!!!

Prepared by Meteorologist LARRY COSGROVE

[Carvers Gap]

This really should not be a tough forecast, especially when you consider how well the comprehensive analog system has worked since last winter (just one truly bad call, that being for a warmer March 2014). There is a definitive +PDO signal, what with cooler SST anomalies over the interior of the northern Pacific Ocean and very warm deviations off of the shoreline of North America from Alaska down to Baja California. A weak El Nino is setting up, basin wide in nature but serving to enhance tropical forcing more in the Orient and near the International Dateline, in a "Modoki" fashion. Blocking has been prevalent in the -EPO, +PNA, and -AO positions since Labor Day, and the chance for more positive height anomaly formation should regroup over Baffin Island and Hudson Bay in the longer term.

But there is a fly in the ointment, namely the statistical models such as the CFS and ECMWF weeklies and monthlies. Those longer term outlooks can best be described as wall-to-wall warm over the U.S. and Canada, continuing a trend seen since the summer months. Yes, these schemes have been wrong, often embarrassingly so. But the GFS and GGEM ensembles fail to see high-latitude ridging returning in the 11 - 15 day period, making the European equation variants somewhat of a loner. Because there are some predictions that are reluctant to get the U.S. back into the freezer, so to speak, the idea I am going with is that it may take another storm moving from Texas into New England November 29 - December 1, to reset the blocking configuration and chances for widespread cold air intrusions that the nation has gotten used to after Halloween.

As far as December goes, I have not really changed my mind about the temperature and precipitation forecast. I made slight revisions to my analog roster, which now includes 1926, 1952 (twice), 1957, 1960, 1968, 1976 (thrice), 1979, 1985, 1986, 1995, 2002 (thrice), 2004, 2006, 2009 (twice), and 2012. The 500MB longwave pattern in the Northern Hemisphere between November 1 and 10 strongly resembled that of 1952 and 1976. The elongated warmer water display from Alaska southward to the Mexican coast is similar to 1957. The deep snowpack seen across Eurasia and North America is fairly close to that of 1976, when a typhoon injection occurred along the lines of Nuri. What it all boils down to is that the western and north central states may have a run of fair and relatively mild days thanks to strong ridging (+PNA), while an active storm track helps hold readings down along the southern and eastern tiers of the U.S. One consideration with the big blocking signature and a very negative 500MB height anomaly n the Northeast: there is potential in this pattern to get a strong cold shot and a major winter storm of the Nor'easter kind, most likely around the big holiday week.

Let it snow. Let it snow. LET IT SNOW!!!!

Prepared by Meteorologist LARRY COSGROVE

Was a great write-up by Larry IMO. Basically is the argument from here two days ago. Global signals point to a banner winter. The long range models cast doubt on the persistent theme of a cold winter. My guess, we have a good winter...but not severe. Will be warmer than many have predicted, but satisfactory for those who love snow. It does seem that the wx models are not recognizing pattern shifts until the table is set so to speak as evidenced by their flip to cold with the latest typhoon which spawned snow in the Apps. Does it happen again? I suspect yes. But going against the weeklies will get you burned...so I defer to those at the moment while knowing a quick flip is probably in the cards later in the period. I also think those expecting a record setting winter will be bitterly disappointed. If I get my 10-15", I will be happy. But a weak Nino, if it develops as predicted...will make some west of the Apps happy campers, even if the winter is not a record setter. For the record, I see winter as Dec-Feb for temps and for snow averages...first snow to last snow.

[John1122]

12z GFS has brief warming around the 23-25th timeframe but sends us back into snow showery/cold weather in the 10-15 day range.

[jaxjagman]

 

Looks windy this coming weekend

[jaxjagman]

12z GFS has brief warming around the 23-25th timeframe but sends us back into snow showery/cold weather in the 10-15 day range.

 

Euro is liking your thinking as well

[jaxjagman]

[tnweathernut]

For all the maps and indexes that were pointing at a major warmup just a few days ago, that seems to have largely been contradicted by recent model runs (especially the Euro).  The day 10 now has the looks of a below normal pattern.  The extended Euro shows another impluse on the heels of the system to the lakes next week. This one should take a more southerly route.  Current projections show it go go negative tilt in the southeast, with a fairly potent high to the northwest of it.   This is the way to sneak an "other than all rain" system around Thanksgiving for some.  Time will tell, but the day 10 Euro map has a pretty good look to it.  Certainly not the look of a major warmup anymore.

[John1122]

6-10 day from the CPC has retreating warmth, switching to below normal with above normal precip in the 8-14. 

 

We'll eventually bounce into an extended warm pattern, but hopefully it's only for a couple of weeks and it's ready for a re-load by Christmas. 

 

The AO may flip low positive/neutral in the 6-8 day range but it looks like it may be heading back negative in the 12-14 day range.

[John1122]

As of now the mean temps for the month will likely finish several degrees below normal with the current cold and the predicted warm up being low Probably in the 42-44 degree range for Knoxville and Nashville. The last time November was this cold was 1995, when the mean was 42 in Knoxville and 43 in Nashville. We'll see if it bodes well for the upcoming winter. The warm winters we had in the late 1990s to early 2000s featured almost exclusively above normal November means in both locations, a lot were quite a bit above normal at 50+ degrees.

 

So the November cold pattern is actually fairly encouraging to me in how it may reflect on winter overall. 

[metwannabe]

If you go by history the argument can be made that the AO tanks during the first week or two of December. Octobers of past that had a negative AO had a strongly negative AO in December

[tnweathernut]

Robert just doubled down, talking of a pattern flip back to cold and interesting toward the end of November after a brief warm up. He thinks each month from December to March has the chance to deliver winter storms. Fascinating write up on his website.

I am really rooting for some warmth around Thanksgiving and into December. Maybe, just maybe.