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Author Topic: Winter 2018-19  (Read 8168 times)

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Offline StormNine

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Re: Winter 2018-19
« Reply #60 on: September 22, 2018, 04:56:43 PM »
It is probably too early but I won't have a lot of free time in Oct-early December so I will go ahead and post my thoughts and way too early prediction for the winter now.

The major factors will be:

- Weak to Moderate West-Based aka Modoki El-Nino.  I am thinking similar in the strength to 2006-07 but unlike 2006-07 this will likely be a Central Pacific type of El-Nino.  These tend to be better for us in the Eastern USA.

+ PDO which tends to lead to riding in the Western USA

The QBO trend that Curt described

- An active subtropical jet which we have seen already.  San Antonio now has their wettest September on record.   

The pattern we will start to head into in the coming weeks is likely a sign of what is to come for much of the winter.  There will be relaxation periods just like we had in 2009-10 and 2014-15 but I have reason to believe we are in for a very solid winter for the Southern and Northeastern USA. 

Color Map:
Orange: Above Normal +1 to +3 temperature departure
Red: Much Above Normal Greater than +3

Blue: Below Normal -1 to -3 temperature departure
Dark Blue: Much Below Greater than -3




I will go with climatology and say that late-November and December will be a relaxation between a colder than normal October-early November and what follows.  As long as we avoid a strongly +NAO or +AO then I will think that our area will finish close to average temperature wise and may find a way to at least sneak in a winter event.

Chattanogga: +1.0
Memphis: +0.8
Nashville: +1.0
Tri-Cities: +1.5 

 

I think here is where the +PDO and favorable Pacific conditions will overall lead to paydirt. With potential blocking in the Northwest and SE Canada and into Greenland that will allow for winter air to pour into our area and linger starting in January. The teardrop shape is due to the potential for the ridges to intrude at times in the Northern Plains.  An active subtropical jet should also help temperatures down quite a bit in the southern USA by way of precipitation and cloudcover.

Chattanogga: -3.1
Memphis: -3.0
Nashville: -2.5
Tri-Cities: -2.5



Another day and another cold February prediction.  I thankfully didn't predict a cold one on 2017, but the 2018 and 2016 calls were major busts.  Our last two Modoki El-Nino's (2010 and 2015) were solidly below average in the temperature category.  As long as the Pacific cooperates we may not even need a -NAO/AO as a strong +PNA may help in assuming a Warm to Hot West and Cold East pattern.  Will this one bust or will this one verify as 2010 and 2015 did?  We will have to wait and see.  I do think there is a strong potential for at least a Top 10 Warmest February on record in the Pacific Northwest. 

Chattanogga: -5.0
Memphis: -3.5
Nashville: -4.0
Tri-Cities: -4.5

Precipitation:



Typically in weaker El-Nino events the subtropcial jet is suppressed a bit further south.  With the potential of some potent cold air masses I will agree with that decision and go with a drier than normal winter for our area.  Remember that if much of our precip is snow we will likely up drier than normal as 1 inch of snow comes to only 0.10 of an inch of rain and it could be as low as 15:1 or even 20:1 in really cold airmasses. 
« Last Edit: September 22, 2018, 07:33:09 PM by StormNine »

Online Clint

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Re: Winter 2018-19
« Reply #61 on: September 22, 2018, 05:43:33 PM »
StormNine, thanks for posting your thoughts for this upcoming Winter... but I'm curious, you have Memphis at +3.0 for January temps. Would that be a typo?

Offline StormNine

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Re: Winter 2018-19
« Reply #62 on: September 22, 2018, 07:40:57 PM »
StormNine, thanks for posting your thoughts for this upcoming Winter... but I'm curious, you have Memphis at +3.0 for January temps. Would that be a typo?

It should be a -3.0 and not a +. Those little typos get me all the time. 


Offline JayCee

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Re: Winter 2018-19
« Reply #63 on: September 25, 2018, 08:42:44 PM »
The Sun set at the North Pole yesterday, and won't rise again until spring.  Twilight will continue to deepen into the long, dark night of winter. 

http://www.athropolis.com/sun-fr.htm
"For many years I was self-appointed inspector of snowstorms and rainstorms, and did my duty faithfully, though I never received one cent for it.." 
Henry David Thoreau

Offline Curt

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Re: Winter 2018-19
« Reply #64 on: October 14, 2018, 01:08:30 PM »
Getting nearer to more accurate forecasting tools for winter

Euro seasonal mean of 51 members for December to February



JMA for same period

Offline JayCee

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Re: Winter 2018-19
« Reply #65 on: October 14, 2018, 01:48:09 PM »
Getting nearer to more accurate forecasting tools for winter

Euro seasonal mean of 51 members for December to February



JMA for same period


Lookin' good in our neighborhood. 
"For many years I was self-appointed inspector of snowstorms and rainstorms, and did my duty faithfully, though I never received one cent for it.." 
Henry David Thoreau

Offline BRUCE

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Re: Winter 2018-19
« Reply #66 on: October 14, 2018, 01:49:29 PM »
Getting nearer to more accurate forecasting tools for winter

Euro seasonal mean of 51 members for December to February



JMA for same period

and with much of canada showing above normal temps...perhaps that will keep out pattern from being supressed  ... which is a good thing...could be lot ice this winter for our area ::doh::
Come on severe wx season...

Offline Curt

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Re: Winter 2018-19
« Reply #67 on: October 14, 2018, 02:43:55 PM »
and with much of canada showing above normal temps...perhaps that will keep out pattern from being supressed  ... which is a good thing...could be lot ice this winter for our area ::doh::

Actually that’s the pattern at 500mb not temps.

Offline StormNine

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Re: Winter 2018-19
« Reply #68 on: October 14, 2018, 08:00:42 PM »
One thing to stress about forecasts that may be seen is that if we have a solidly colder than normal winter than we will have a greater than normal chance for below average precipitation.  Remember that snow on average has only 1/10th the water content as rain, so if a good deal of our winter precipitation falls as snow than we will likely be below average precipitation-wise (see 1963-64 and 2009-10). 

I want to say that because a lot of people see below average precipitation and temperatures and assume suppression city. 

Post Merge: October 14, 2018, 08:14:20 PM
One thing I have noticed from the long-range models is that they aren't showing much of a warm-up in November-December and typically that timeframe leans warmer than average for the Southeastern USA in El-Nino years.  That will be an interesting thing to watch over the coming weeks.  It is quite rare to go below average in all three winter months especially post 2000.  With that in mind and this current cool-cold wave for this time of year it would make sense to have a period of warmth during that time.  The good thing is if we have our warm period in November-Early December then we potentially time our next cold shot for the Holidays and into the heart of the winter.   

We shall see.
« Last Edit: October 14, 2018, 08:14:20 PM by StormNine, Reason: Merged DoublePost »

Offline BRUCE

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Re: Winter 2018-19
« Reply #69 on: October 14, 2018, 08:40:47 PM »
One thing to stress about forecasts that may be seen is that if we have a solidly colder than normal winter than we will have a greater than normal chance for below average precipitation.  Remember that snow on average has only 1/10th the water content as rain, so if a good deal of our winter precipitation falls as snow than we will likely be below average precipitation-wise (see 1963-64 and 2009-10). 

I want to say that because a lot of people see below average precipitation and temperatures and assume suppression city. 

Post Merge: October 14, 2018, 08:14:20 PM
One thing I have noticed from the long-range models is that they aren't showing much of a warm-up in November-December and typically that timeframe leans warmer than average for the Southeastern USA in El-Nino years.  That will be an interesting thing to watch over the coming weeks.  It is quite rare to go below average in all three winter months especially post 2000.  With that in mind and this current cool-cold wave for this time of year it would make sense to have a period of warmth during that time.  The good thing is if we have our warm period in November-Early December then we potentially time our next cold shot for the Holidays and into the heart of the winter.   

We shall see.
yeah but also ... El Niño’s favor a active southern storm track... we shall see
Come on severe wx season...

Offline dwagner88

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Re: Winter 2018-19
« Reply #70 on: October 14, 2018, 09:00:31 PM »
At least in Chattanooga, presence of gulf moisture has a much stronger positive correlation with above average snowfall than cold temperatures. We've had a lot of good winters with marginally cold (or even above normal) temps when systems are able to tap the gulf. If we get cut off from the gulf (suppression) we get nada (see last winter). It is basically impossible for clippers or NW flow snow to fall here due to topography. Feels like we are overdue. I haven't seen more than a half inch on the ground here since 2015.
Winter 2009-10 Snowfall: 11.5 in. :)
Winter 2010-11 Snowfall: 15.5 in. :)
Winter 2011-12: Trace
Winter 2012-2013: 0.25 in.
Winter 2013-14: 10.6 (9.5 on 2/12)
Winter 2014-2015:
2/18 - 0.25" snow
2/20 - 1.5" snow, 0.15" ZR
2/24 - 0.5" snow
2/25 - 8" snow :)

Offline schneitzeit

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Re: Winter 2018-19
« Reply #71 on: October 14, 2018, 10:46:26 PM »
Knoxville can get lucky with those clippers during colder than normal winters. Chattanooga doesn't have the advantage that NE TN and the Plateau has with those weak clippers. I think that's another reason why Chattanooga didn't cash in on anything last year. The main culprit for the paltry amount of snowfall in Chattanooga was a very strong trough which sent everything south early on, followed by an abrupt pattern change in which it would either be rainy and 50-60 or sunny and 35, with any sort of activity during cold weeks going north.

We can still strike those blockbuster storms during warm years. 2015-2016 was warm as crap (though most of that was due to the epically warm El Niño-induced December torchfest) but Middle TN cashed in on Jonas.

Offline JayCee

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Re: Winter 2018-19
« Reply #72 on: October 15, 2018, 07:51:44 AM »
This is the current 8-14 day outlook.



I only post this pic because the upcoming winter may look a lot like this.  Tennessee could be in the transition zone between wet and dry.  Timing is everything in this pattern, and many times before a dry northwest flow sets up, a strong storm system will ride up from the Gulf into the northeast.  That's when we tend to get our significant snows--in a pattern transition to a deep Eastern trough.  Once the deep trough is in place, we're dependent on clippers tapping enough of the Gulf to drop a few inches here and there.  The plateau and mountains do well in a northwest flow, but the lower elevations need a decent disturbance to generate enough lift to get more than a dusting--especially areas like Chattanooga.

Anyway, let's hope Tennessee is in a sweet spot this year--the battle zone between a cold, dry north and a milder, but wet, Deep South.  Everything points to a better winter than the last two, but we know how that goes sometimes. 
"For many years I was self-appointed inspector of snowstorms and rainstorms, and did my duty faithfully, though I never received one cent for it.." 
Henry David Thoreau

Offline BRUCE

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Re: Winter 2018-19
« Reply #73 on: October 15, 2018, 08:17:39 AM »
We use to have some decent clippers years ago west tn... but they seem to be less and less each passing winter .... not to big on clippers ...
Come on severe wx season...

Offline snowdog

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Re: Winter 2018-19
« Reply #74 on: October 15, 2018, 08:51:07 AM »
Getting nearer to more accurate forecasting tools for winter

Euro seasonal mean of 51 members for December to February

That's it, I'm going on Amazon right now and buying a new sled.  ::snowman::

 

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