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December/January 2019/20 Winter Speculation Thread

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3 days later another winter storm approaches. Doesn't quite reach here on the precip maps but it's a set up for a classic event here as the Northern edge of precip is almost universally under modeled.  Of course it will change 20 times in the next 10 days. 

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The 0zgfs was a cold run for sure. It's probably overdone but has a 1050mb at 168hrs coming down the plains, but what's suprising in a way is that the front dont stall and form a big Overrunning event but that's why I'm not a weatherman lol.

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58 minutes ago, Mr. Kevin said:

The 0zgfs was a cold run for sure. It's probably overdone but has a 1050mb at 168hrs coming down the plains, but what's suprising in a way is that the front dont stall and form a big Overrunning event but that's why I'm not a weatherman lol.

Your area looks like it's in a spot that's liable to get really icy. 

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06Z GFS flips to full on winter for all of us starting a week from today. Pretty cold look with multiple chances for wintry. I would guess its likely not accurate with the lasting flip to cold throughout the run. But I'm sure feeling better about the pattern reshuffling in a week or so.

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GOES model starting to support the GFS in knocking around the SPV a little. 

GOES:

giphy.gif

GFS:

giphy.gif

Here's what it looks like in a more colorful, but 2D gif:

giphy.gif

That one is at 50mb, which should correlate to around the 650 level on the Potential Temperature scale on the 3D models. 

 

 

Euro doesn't look anything like the GFS,

giphy.gif

but the GFS does have a better track record with these, at least the past couple of years.

If this were to happen, I wonder if because the SPV was so strong and well coupled with the troposphere, if it might have more effects than previous ones? 

 

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On a positive note.... looks like the rain this weekend will not be the monsoon it looked like a few days ago. Saturday morning golf looks like a go.


.

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Regarding the 12z GFS.  We now have one winter threat in the d8 range and closing.  The timing of these (potential) cold air masses surging southeastward is going to obviously be critical.  Memphis and much of the western forum area(eastern Arkansas, western KY, northern MS, and sw Missouri) look to be sitting in a good spot for late next week when the first round of cold arrives.  It really looks like we are going to see cold come southeast and have difficulty moving as the next system from the STJ "attacks" the departing high.  The GFS appears to have reverted to its 18z progression at 500.  Nevertheless, the surface looks quite similar if not a bit warmer than 6z.  How far that wintry precip spreads eastward is going to depend on where high pressure is, how much cold we get, and how quickly it retreats.  Classic set-up for the western forum areas if it verifies.  

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Massive 1050 high at 252 slides in right behind that system.  I like seeing repetitive cold shots and an active STJ...understatement of the new decade, right?  Great example of how modeling really likes significant cold to come into play after January 16/17.  Good storm signal.

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How many hours above freezing are we once we get to about to 252 give our take 6 hours to account for your location?...not seeing many at TRI.  That was an incredibly cold run.

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ECMWF Op is slower than the GFS on the cold next week. However the EPS is colder than the GEFS in the 11-15 day range. Hopefully my Panic Room I post ages well. Darth Vader: I find your lack of faith disturbing.

Thursday GFS runs have been cold in the extended, some stormy. Now those 11-15 day systems could go anywhere from Ohio to Florida; but, no worries if an 11-15 day storm cuts or is too buried. Main thing is the GFS has a cold 500 mb pattern. Is it just the dumb operational? GEFS isn't running as cold. Well, the EPS is running that cold. Perhaps the colder 500 mb weather pattern should be favored. EPS has also destroyed the GEFS recently; so, I kind of like a cold EPS.

Also some evidence the EPS is handling the MJO and other tropical signals better. I'm not sure about the SPV jostling, but Holston I love those 3D graphics either way. Finally the CFS is frozen so maybe the GEFS will go that way. See what the ECMWF weeklies have tonight. They are based on the 00Z (previous am) EPS so probably cold.

Closing with some non-model data. Jax has good posts in our ENSO thread. With the IOD relaxing but El Nino trying harder, perhaps the MJO will spend more time in true Pacific cold phases, vs just a secondary echo off the IOD. Still got convection in warmer phases, but there's plenty building in the colder phases too.

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Wow! A real life +PNA and cold that does not look especially transient, right in the heart of peak winter weather climo. We won't know what to do with ourselves if that look holds. 

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Thought I’d give a quick update on the mountain wave event. Already getting some gusts of around 60mph at Camp Creek today, but this isn’t the main event. 

There are still a few things that could go hinder mountain wave development this weekend. As Jeff mentioned in the Severe Weather topic, the NAM has shown signs of wanting to keep 700mb winds more southerly. If that happens, then that could hinder the critical layer development (need SW winds at 700).  Also, if there is any instability near the mountains, that could also decrease downslope potential.  With that said, if everything comes together this could be a very significant wind event. The parameters are some of the best that I can remember. Just talking potential, because it’s impossible to say for sure when you are talking about wind speeds within stationary gravity waves.

Here is one example of the Euro wind gust output. Not sure how reliable this particular product is, but models always underestimate winds with these events (along the mountains) so it caught my attention.

 

MW11120.png

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1 minute ago, Math/Met said:

Thought I’d give a quick update on the mountain wave event. Already getting some gusts of around 60mph at Camp Creek today, but this isn’t the main event. 

There are still a few things that could go hinder mountain wave development this weekend. As Jeff mentioned in the Severe Weather topic, the NAM has shown signs of wanting to keep 700mb winds more southerly. If that happens, then that could hinder the critical layer development (need SW winds at 700).  Also, if there is any instability near the mountains, that could also decrease downslope potential.  With that said, if everything comes together this could be a very significant wind event. The parameters are some of the best that I can remember. Just talking potential, because it’s impossible to say for sure when you are talking about wind speeds within stationary gravity waves.

Here is one example of the Euro wind gust output. Not sure how reliable this particular product is, but models always underestimate winds with these events so it caught my attention.

 

MW11120.png

I saw that MRX actually started putting social media posts out about it already. I wonder how many places in the United States have such a unique local phenomenon. I know Mount Washington gets extremely high winds but I don't know if that has anything to do with mountain waves.

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4 minutes ago, Holston_River_Rambler said:

I think I found it on weathermodels:

giphy.gif

so I guess it is just off the ground, like 30 feet? 

That seems to match the graphic I posted.

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17 minutes ago, John1122 said:

I saw that MRX actually started putting social media posts out about it already. I wonder how many places in the United States have such a unique local phenomenon. I know Mount Washington gets extremely high winds but I don't know if that has anything to do with mountain waves.

I know Boulder, CO gets mountain waves too. My former advisor during graduate school wrote a paper on it. Strange coincidence that we both had interests in mountain waves.

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38 minutes ago, Math/Met said:

I know Boulder, CO gets mountain waves too. My former advisor during graduate school wrote a paper on it. Strange coincidence that we both had interests in mountain waves.

Math/Met, what is the timing for this event on Saturday - more late in the day?  

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Area around the Medicine Bow Mountains in Wyoming do also. I've experienced those in that area not too far from Laramie with East winds especially.

 

Sent from my SM-G965U using Tapatalk

 

 

 

 

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19 minutes ago, Carvers Gap said:

Math/Met, what is the timing for this event on Saturday - more late in the day?  

It is a prolonged event,  but wind gusts should pick up by Saturday morning and continue into the evening.  The strongest LLJ winds move in later in the day. Sometimes there's a weakening of winds during the afternoon, and it gets stronger as the sun goes down.

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8 minutes ago, ShawnEastTN said:

Area around the Medicine Bow Mountains in Wyoming do also. I've experienced those in that area not too far from Laramie with East winds especially.

 

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Awesome.  Wyoming is one of my favorite places.  The winds there can blow at hurricane force for days on end on the Plains out there.  I follow some pages on FB(Wyoming through the Lens) which shows some crazy snow drifts that the can get from just 4" of snow.   The event last week that was blowing over trucks was incredible.  Wasn't really a mountain wave event, but was impressive.  I have been caught in thunderstorms out there that push through.  Nothing quite like the winds in that are of the world.  Easily is my favorite weather state.  I would imagine The Winds, Salt, Bighorns, and any range in SE WY(like the Medicine Bow) have some crazy spots.  Another cool deal are these little indentations called the Peter Sinks in Utah where they have some of the coldest temps in the lower 48.  These indentations get crazy cold.  Some researches thing these little cold indentations are found in Antartica as well and likely could break all-time record lows.  What is crazy is that you can walk into these little spots within a matter of a few steps.  Another place that gets fierce winds off the mountains is Browning, MT, on the reservation there.  Not really a mountain wave deal, but still impressive.  Kind of cool that we have this here in Tennessee though.

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