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Winter Speculation 17/18 -December Thread


AMZ8990

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In case you guys don't know how the AAM works,here's phase 3 of what the map shows above

 

Phase 3 (La-Nina like) – the global relative AAM anomaly is negative. The negative anomaly is primarily due to easterly upper level wind anomalies that extend from the Eastern Hemisphere tropics to the Western Hemisphere mid-latitudes. A retracted Pacific Ocean jet stream is a key feature in the total field.  Troughs are probable across the western USA with a ridge over the southeast.  High impact weather is favored across the Plains and the Pacific Northwest.

 

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1 hour ago, weathertree4u said:

So, if that were to occur, how soon are we talking in the lower 48?

I always get mixed up on the timeline.  I want to say 2-3 weeks, but I may be thinking of the index that it takes to lead up to this.  

Weeklies Update:  Warmup still looks on track for Jan 20 to Feb 5 w maybe one or two cold shots during the warm-up.  Some very warm days will be had.  Same reasoning as before still applies when discussing a way around the warm-up.  Highlights....Trough returns to the East sometime during the timeframe of Feb 5-12.  After that the Weeklies now actually show cold at the 850 and 2m levels advancing to the EC.  That cold looks very much like the current cold period w the model showing a similar and rare, strong cold signal at range  on the EPS.  I think this time we see precip w the cold as the wavelengths change as we near spring.  “Oh spring, where art though?” says this Weeklies for this run.  It goes through March 2nd.  It looks very cold against the norms during that week w no let up in sight.  The process for the trough to swing eastward is set into motion during early Feb(before the 5th).  The 46 day temp anomaly has almost ALL of the lower 48 below normal.  Only South Florida escapes.  Snow means are nice.  10-12” for NE TN.  Looks like a nice 2-4 week stretch of winter to end the season...three weeks seems like a good fit. And a final plus, this run of the Weeklies was run from a pretty warm 0z run...normally that correlated to warm Weeklies.  And as the famous Bob Chill always says...the Weeklies can flip on a dime.  Their skill is best to about week 3...but they have been decent this winter though not infallible given the massive snow means that busted from December.  But it nailed the cold.  The Weeklies have been pretty consistent with this look and timing of warm/cold.  But they doubled down this evening on the cold.

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4 hours ago, weathertree4u said:

Seeing the flooding rains showing up again in the long-range of the GFS as of its 06z run. Hope this is just an error of some sort but has shown up a few runs now....

Nothing would shock me when it comes to rain actually verifying. But the GFS beyond day 2 is struggling badly this year with details. It actually had the system as snow for a few runs. 

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3 hours ago, nrgjeff said:

It'll get cold again in Feb. 

 

We are nickle and dimeing our snowfall this year. With todays my back yard has had around 7" - 8"; the winter so far reminds me of 2003 - 2004 where we had several small snow systems. Still want at least one big snow like I remember as a kid, one that puts down at least 6"

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2 hours ago, weathertree4u said:

We are nickle and dimeing our snowfall this year. With todays my back yard has had around 7" - 8"; the winter so far reminds me of 2003 - 2004 where we had several small snow systems. Still want at least one big snow like I remember as a kid, one that puts down at least 6"

I have had less than an inch for the entire season....I am not even nickel and dimming.  More like pennies and cut-up credit cards.  

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I have had less than an inch for the entire season....I am not even nickel and dimming.  More like pennies and cut-up credit cards.  

 

Really? I'm not that far away from you as the crow flies. I got a couple of inches here during the Dec. 8th event and another half inch a few days ago. I mean, that's hardly bragging material, but I'm surprised you're still under an inch.

 

 

 

 

 

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7 minutes ago, Windspeed said:

 

Really? I'm not that far away from you as the crow flies. I got a couple of inches here during the Dec. 8th event and another half inch a few days ago. I mean, that's hardly bragging material, but I'm surprised you're still under an inch.

 

 

 

 

 

Several dustings.  Maybe a quarter or half of an inch on one storm.  The December 8th deal we had almost nothing.  I could drive less than five minutes and be in snow though.  Roan had a foot.  But definitely under or right at inch so far for the season.  

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14 hours ago, weathertree4u said:

We are nickle and dimeing our snowfall this year. With todays my back yard has had around 7" - 8"; the winter so far reminds me of 2003 - 2004 where we had several small snow systems. Still want at least one big snow like I remember as a kid, one that puts down at least 6"

I know what you are saying but anybody north or west of Nashville has been cashing big checks compared to the rest of us. :D

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I will add that I am good w/ the 1" of snow for this event that I have combined w/ cold that we have had.  I like cold almost as much as snow.  And I did get to drive to the mountains and see one foot back in December.  Nice to see areas in the forum get snow that have been on a bit of a drought.  We have not really had a decent snow here at TRI in quite a while.  Interestingly, TRI is the one with the snow drought now which brings me to some mid to LR thoughts.

1.  The operational 0z Euro really does not look like it wants to move the ridge out of the West.  The 6z GFS really never leaves the current pattern.  The GEFS is not a torch by any means.  Even the GEPS has tempered its torch a bit.

2.  The 0z EPS does move the ridge eastward.  It has been doing this for what seems like weeks and has yet to truly verify.  Now, the EPS has been very good this winter.  It has probably been my favorite model of all of them combined w the RGEM for short range.  

3.  Yesterday's MJO certainly wanted to go COD on several models sometime in the phase 4 range.  Then it travels towards phase 7.  If one based the rest of winter completely based on the MJO timing...not good.  By the time it would reach favorable phases of 8,1,2...we would be almost to mid February and the clock quickly ticking towards spring.  But the w the MJO forecast going COD or low amplitude, it makes me wonder if that signal will be severely muted.

4.  The Weeklies looked very good from the second week of February forward w a similar cold signal to the one that we had during late December....but w storms.

What does this all mean?  Lots of uncertainty but w potential for lots of upside.  Pretty similar to taking a three star linemen who played in a less visible league but is 6'-5" and 285lbs as a HS senior.  You don't really know what you have until he hits the field, but he looks the part.  It does concern me a bit that the current pattern won't break.  Why?  Because this pattern will break, and break to a western trough IMO.  I would prefer it to break now and then give us a chance for cold to come back in Feb.  The longer this waits, the more of February is eaten up w the trough in the West.  There is experience from past winters that has me concerned that we actually break for spring if this pattern breaks too late...a really cold spring at that.  Now, the other idea is that we get a thaw w 4-5 days of very warm temps and the rest is marginal within the context of a progressive flow.  Then, we hit the true cold of early to mid February...and the party is on.  I lean towards the last statement...but with one eye over my shoulder at a trough locking in the West.  I do think the -QBO might be a nice tipping point while considering Occam's razor.  Take the simple explanation.  We have a -QBO during a weakish Nina...those usually correlate to cold winters in our forum area w high latitude blocking and w one big thaw in the middle.  Again, those ideas have served us well up until now.  Enjoy the snow and the warm weekend.  

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I have been happy for all of those west and south/southwest of me seeing multiple snows to this point.  Several weeks ago Carver's and I had some side discussions and thought this would be a pretty good period for the western part of our forum and that seems to have panned out nicely.  Snow is a fickle critter, so of course there have been winners and losers, but to have multiple snows reaching all the way to the gulf coast before we get out of mid January is REALLY impressive and the cold has been historic! 

I'm sitting at 2.75" for the winter and seem to have done better than Carver's to this point (just a bit north of me) and the airport (just 5 miles ENE of me). If it hadn't been for the early December couple of inches, things would be pretty ugly around this part of the southern apps

I have always viewed snow that falls before mid January as bonus snow in the mid-south...  Late January to late February is usually the money month for snows as the jet continues to lower and the wavelengths also change.   It's mostly felt like winter since early December, which hasn't been typical the last 2+ decades.  It will be interesting to see how the rest of our winter season plays out.

 

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As suspected, the second system did not take the low road.  Looks like rain on the 0z Euro run.  

Now for semi-good news, the most most current major ensembles (0z CMC,0z EPS,6z GEFS) now show a displacement of the western trough eastward.  Now, it is not fully in the East yet.  But by early February the EPO ridge is back in the eastern Pacific, and it would appear that it is only a matter of time before the trough re-establishes in the East...but with what I suspect will be a much more active pattern.  We will need to watch in the coming days if this shift is moved forward in time.  Honestly, if one accounts for the EPS tendency for hanging the trough out West....it would likely almost have the trough in the mid-section of the country by d15 which is Feb 2nd.  It looks remarkably similar to the transition that occurred just before Christmas.  Canada is very cold.  That cold is pushing slowly down the front range of the Rockies.  I think the cold would arrive sometime between Feb 5th and 10th.  Again, I strongly doubt that this would be a dry pattern just given the time of year.  Bout it for now.  Euro Weeklies roll tonight.  The pattern that sets the thaw into motion by this weekend, begins today.

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Maybe making something out of nothing...but I like the look of the pattern around 156 on the CMC and GFS both.  The 12z GFS has a hp over the top in the GL w energy sliding along the GOM.  The CMC is a bit different but still some energy cuts across the GOM.  Plenty of moving parts, but a marginal possibility is there.

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