Fall 2016

[Carvers Gap]

Really no new news at this point other than the pattern has changed from one of extreme heat to seasonal.  Looks like a very back-and-forth pattern is on the table for the next 2-3 weeks.   With above normal heights over the Hudson Bay, it looks like cold will build in western Canada over time.   It will then move southward into the Rockies and slide east.  Reminds of the winter patterns of my teens and childhood.  We would often look to the Plains as our cold here in TN often originated there.  I used to always keep an eye on the temp in International Falls.  If it wasn't cold there, it wasn't going to be cold here.  As a grown-up, I know that is not always an accurate metric, but it was fun then.  I also used to watch for it to get cold in Memphis and Paducah.  This might be one of those winters where the cold races down the east slopes of the Rockies and surges west in a repeating nature.  The good thing about that IMO is that the cold might not suppress systems to the GOM.  Instead of the cold diving to the GOM, it is racing west to east.  There might be some cutters that benefit Memphis.  A weak SER might be in place.  But I will take my chances w/ that.  Looks like the cold finally builds eastward in roughly eight days w/ a back and forth pattern of warm/cold.

[John1122]

I'm still hoping one of the rain systems actually produces and doesn't fall apart. We need the cold to land in the west to turn the flow sw here. If we can get that it will help with moisture transport from the Gulf. 

Outside of that, I'm hoping for a cold pattern by Mid-December. It can snow here any time from Mid-November on basically but it obviously is easiest if we have cold in the December-February time frame. 

[Daniel Boone]

Imo, with the western trough, we'll need a strong -nao for us to do any good snow wise,ala; jan-feb. 1978-79. There's some that believe a trough and associated cold always comes east with time. As most of us know, that's not the case. Our warmest, least snowy winters featured the persistent western trough. In fact, one of many forecasters analogues(isotherms top) , 73-74, is the least snowy on record for much of this area. Ktri recorded about 3 inches that winter. I remember it well. hated it!

 Since some drivers are different now from then, particularly the AO, I'm hoping for a different outcome.

[John1122]

If there's a persistent western trough it'd be awful for snow chances in the long run. My reference to it is for it to happen in the coming week or so, so we can maybe get some SW flow into a system and let it transport gulf moisture over us. I'm fine with rain systems in November and the first half of December.

 

Who knows if it happens, but the GFS builds a -NAO and a +PNA  and unleashes cold fury from Northern Alaska, through Central Canada and into the Southeast in the long range. By the end of the run we're talking -10 to -15 degree early evening temps in the upper Midwest and Southern Canada.

 

[Carvers Gap]

The current models set-up in the LR should provide return of precip from the GOM w cutters.   We need rain.  Overall, it took a while to get into this pattern...going to take some time to get out of it.  But if we don't get out of this drought, snow chances will be minimal anyway no matter the temp.  The above normal heights over the Hudson Bay, weak Nina, and high latitude blocking of some variation argue for chances in the upper South.  As the cold gets established in NA, the current set-up of cold going west to east could bring some sliders into play.  Obviously we will have to deal w cutters...but those can bring rain as well.  Last week we were worried that the Pacific was flooding NA w warm air.  Now, the models show a trough w cold spreading east.  IMO, the West gets cold first as it does during many winters.  But building cold over western and interior Canada is good if you live west of the Apps.  I said in early Fall that I like the chances for the western third of the state that has been a severe snow drought.  But overall, I think we all see chances...maybe plenty of them.

[Carvers Gap]

What will be interesting to see is how a potential -PNA and blocking over Hudson Bay interact.  Some great winters had above normal heights centered near HB.  We have been in a +PNA/+NAO/-AO winter pattern for many of our most recent/decent winters.   There are other patterns that produce ice/snow.  It is possible to get snow here with the West being cold.  Either way, I am glad to see the record heat gone w rain chance improving on the near horizon.  The pattern is changing.  

[Daniel Boone]

Agree with you John and carver. Btw, I wasn't saying you couldn't get snow with a western trough, just making a point for those that say that the cold WILL come east as saw those posts elsewhere and on twitter. There were some horrible winters of which weakened transient troughs moved east and we got very little snow. However, as alluded to earlier,very little blocking then . 

  Carver, yeah you would think a hudson block could get job done. depending on how far west that is, wouldn't that be classed as west based -nao ?  

 The -pdo 60's winters featured plenty snow west to east due to strong blockiness. Those sliders you mentioned Carver. Have you all noticed, Seems noone want's to talk about those winters as even remotely possible analogues.

[John1122]

The GFS keeps bringing an ice box run after run. It's just crushing the Rockies and Eastward toward the end of the 00z run. 20-25 degrees below normal showing up and spreading eastward towards the end, tonight a 1050 or so high is coming into the plains. If that came to pass, that's probably some of the coldest early December air in years coming into the country.

[Carvers Gap]

DB, you definitely make a good, valid point about the trough out West and the potential progression of the pattern.  Models from time to time go to that dreaded solution.  I agree with your point.  And yes, John, GEFS is cold.  The EPS seems to flirt with normal vs cold.  I can't tell if it is guilty of holding energy back in the SW. The 12z Op Euro takes cold all of the way to southern  Baja which pops a SER!  Wat!?  The weeklies last night look decent with a warmup in the middle (of the 46-day run) of a week or so.  Looks like cutters early then energy sliding under the block.  Minuse the operational Euro run this AM, most things look on track for the beginning of December and winter.  The operational Euro looked very guilty of its usual shenanigans in the southwest days 6-10, but it is something to watch as the PNA may flip and stay for negative for a time.  The Japanese monthly climate model does show a decent winter FWIW.  Best thing about all models in all ranges is that they show rain.

[Carvers Gap]

From MRX this AM...

For Monday...ridging begins to move east of the area with return of
southerly winds. The GFS and ECMWF are in agreement with developing
a deep long-wave upper trough over the western United States with a
series of jets exiting into the Plains...then Ohio/Tennessee Valleys.
This will allow for the Gulf of Mexico moisture to finally open up
and pull north into the region for mid-week.

The differences between the models is the timing of the upper jets
moving across the area inducing upper divergence/strong fronto-
genetic forcing over the Tennessee Valley/southern Appalachians.
Will call for two waves of frontal-genetic rains...one of Tuesday
and another Wednesday. Also enough instability for Tuesday to
include thunder. Significant rains are finally looking likely for
mid-week.

[Carvers Gap]

The 12z GFS would be the scenario that DB mentioned with the -PNA pattern over-riding the whole pattern.  Hopefully, the GEFS is more mellow to that change.  The operational was a straight torch after day 10.  The 0z EPS solution hints at a weakening of the AN heights over Hudson Bay.  If that happens (nothing is a given at that range) the -PNA rules the roost.  Fairly significant changes today.  Let's see what the EPS shows and the Euro OP at 12z.

[Carvers Gap]

WPO and EPO forecast to go negative could offset the -PNA.  Either way will be interesting to see how things play out.

 

edit: 12z GEFS holds cold in place for the duration of its forecast.  It does weaken the blocking over HB.  Something to watch.

[Carvers Gap]

From MRX afternoon update....Hoping this verifies!!!!!!!!!!

[Stovepipe]

Yesterday multiple GFS runs in a row showed 4 inches, currently 12z showed 2.0 and 18z 1.0.  I really want a good soaking, but I'm so accustomed to getting screwed that by the time this thing moves through I'm bracing for another tenth of an inch.  Hopefully MRX is right and we get heavy rain with 3 inches or so.  Never needed a pattern change so bad.  Waiting on SREF updates!

[Carvers Gap]

1 hour ago, Stovepipe said:

Yesterday multiple GFS runs in a row showed 4 inches, currently 12z showed 2.0 and 18z 1.0.  I really want a good soaking, but I'm so accustomed to getting screwed that by the time this thing moves through I'm bracing for another tenth of an inch.  Hopefully MRX is right and we get heavy rain with 3 inches or so.  Never needed a pattern change so bad.  Waiting on SREF updates!

Models seem to really like TYS south.  Euro and EPS look good there.  NE TN may have to deal with a less robust line of precip as it fades...rain shadow may hurt us as well.

[Carvers Gap]

Bring on the rain...

 

[jaxjagman]

Euro in which was cutting the system off towards next weekend this afternoon no longer does,this would be some big time dumpage(rain) into next weekend for the Mid Valley,if it's anywhere right

[Carvers Gap]

That is a welcome sight...

[Carvers Gap]

12z GEFS and EPS depict a growing cold pattern through d15.  GEM not so much. Still, much of the massive warm anomaly in NA is replaced by seasonal or cold, especially in western Canada.  Weeklies will arrive in a bit.

[nrgjeff]

Mountain wave event could get a little interesting tonight. Update measurements, damage, and other windy facts in OBS.

[Math/Met]

24 minutes ago, nrgjeff said:

Mountain wave event could get a little interesting tonight. Update measurements, damage, and other windy facts in OBS.

I agree.  This appears to be a very favorable setup for a major mountain wave event. 

[Roger Smith]

News about contests ...

Hello, I am dropping into all regional forum banter or chat threads to post some information about contests that you may find interesting. 

On the general forum of American Weather Forums, we have a temperature forecast contest that has been going on here since Eastern gave birth to American Weather. We would welcome some new entrants for 2017; the contest is simple to enter and just takes a minute once you've decided on your forecasts. There are nine locations across the U.S. including IAH and ATL. We predict anomalies from 1981-2010 normals, and the forecasts are scored promptly at the end of each month. I am drawing your attention to the contest a month in advance of the new contest year for two reasons -- (1) people get very busy and distracted around New Years, and (2) the contest has a four-seasons component for the 12 months starting Dec 2016. So this is a good month to jump in and get in a practice round before 2017. Some of the regulars in the contest include well-known forum members that you'll recognize, and the standards are pretty high (albeit I am dragging them down somewhat). So it's a good place to test out your forecasting insights against some of the better forecasters on American Weather. Here's a portal into that forecast contest thread ...

https://www.americanwx.com/bb/topic/49268-december-2016-temperature-forecast-contest/

 

Meanwhile, one other contest I can recommend if you want to make a snowfall forecast for 25 locations in the northeastern and Mid-Atlantic states for Dec to Mar winter 2016-17. This is a separate website that runs just this contest and storm forecast contests that you can enter with e-mail notification provided to remind you if a storm is brewing. Once again, you would recognize a few names in that contest (recent years have seen 15-20 regular participants) and the standards are pretty good, once again an ideal place to work on your forecasting or show it off depending on where things are at. 

http://www.newx-forecasts.com/#RULES

That's the link for the Northeast U.S. snowfall contest website. 

Just to complete the tour, you may know that the central/western forum is the place to go for annual severe weather forecasts (most people make them in the winter months, the 2017 thread will probably open up soon). And make a note that there's an annual North Atlantic hurricane forecast contest also in the general forum here at Am-Wx. I organize that one as well, and usually run an announcement thread in May. 

Well, enjoy your winter and maybe we'll see some (more) of your sub-forum members taking part. 

[Carvers Gap]

4 hours ago, Math/Met said:

I agree.  This appears to be a very favorable setup for a major mountain wave event. 

Winds blew a fire from GSMNP into the outskirts in Gatlingurg.  Surreal footage out of WBIR live feed right now.  Thoughts are with those folks.  Mandatory evac for Gatlinburg.  Roads are packed and at a standstill in places.  Thank goodness it is beginning to rain.... Here is a screenshot off my radar of the smoke plumes.

[1234snow]

Winds blew a fire from GSMNP into the outskirts in Gatlingurg.  Surreal footage out of WBIR live feed right now.  Thoughts are with those folks.  Mandatory evac for Gatlinburg.  Roads are packed and at a standstill in places.  Thank goodness it is beginning to rain.... Here is a screenshot off my radar of the smoke plumes.

Just crazy evening for Gatlinburg and surrounding areas. Like something out of a movie. Praying for everyone there as the situation is very bad. Hopefully the rain can help some but it sounds like a lot of damage has been done.






Right behind Ripley's Aquarium:




Also a weather station in east Gatlinburg measured a temp of 118 degrees with a wind gust of 69 mph before the fire took it out.

[1234snow]

RadarScope image from a few hours ago before the rain arrived.

Also the National Guard has been deployed.

[Carvers Gap]

Raining.  Couldn't have waited one more day.  Whew.

 

[Carvers Gap]

13 minutes ago, 1234snow said:

RadarScope image from a few hours ago before the rain arrived.

 

Also the National Guard has been deployed.

 

Terrible.  The winds picked up embers and carried them for miles creating spot fires all over that area.  

[1234snow]

Terrible.  The winds picked up embers and carried them for miles creating spot fires all over that area.  

It's sad that the system that is bringing the rain spread the wildfire before the rain could get there. A lot of downed power lines around the area was starting fires too. Thank god the pattern is finally changing this week.

[Carvers Gap]

1 minute ago, 1234snow said:

 

It's sad that the system that is bringing the rain spread the wildfire before the rain could get there. A lot of downed power lines around the area was starting fires too. Thank god the pattern is finally changing this week.

 

The weeklies show AN rainfall for the next 46 day period.  It could not have arrived a minute later. I have been out West during big wind events.  I also fish the Yellowstone region from time to time.  Just amazing how quick fires can move with big wind.  Fires can jump fire lines for miles in conditions like we saw late this afternoon.  Fire and mountain wave events are a horrible combination.  I hope we never see that again.

[1234snow]

The weeklies show AN rainfall for the next 46 day period.  It could not have arrived a minute later. I have been out West during big wind events.  I also fish the Yellowstone region from time to time.  Just amazing how quick fires can move with big wind.  Fires can jump fire lines for miles in conditions like we saw late this afternoon.  Fire and mountain wave events are a horrible combination.  I hope we never see that again.

Smoke plume is still there as the first batch of rain has passed.