Jump to content
  • Member Statistics

    17,606
    Total Members
    7,904
    Most Online
    ArlyDude
    Newest Member
    ArlyDude
    Joined

December 15-17th Potential Winter Storm


SpartyOn

Recommended Posts

  • Replies 221
  • Created
  • Last Reply

Yeah the difference between the 18z GFS for the Euro 216 hour storm is just.... they are not even in the same ballpark. 500 MB ridging covering much of the US on the GFS, Euro has a storm.

Yeah the GFS is like non-existent for the second one at the same timeframe...and shears out the first one... :whistle:

Link to comment
Share on other sites

12z Euro ensemble mean has this, FWIW.

12zecmwfens850mbTSLPUS216.gif

12zecmwfens850mbTSLPUS240.gif

That is pretty impressive for them to have it that well defined as far out as that is. Nearly every ensemble member is picking up on something in that time rage. Again remember there is 51 of them.. One cluster is focused on a track towards Chicago, Then there is one over Ohio and then to a lesser extent a cluster near i95.. Spread goes from a track to Duluth ( furthest west ensemble track ) to a nor'easter..

Link to comment
Share on other sites

That is pretty impressive for them to have it that well defined as far out as that is. Nearly every ensemble member is picking up on something in that time rage. Again remember there is 51 of them.. One cluster is focused on a track towards Chicago, Then there is one over Ohio and then to a lesser extent a cluster near i95.. Spread goes from a track to Duluth ( furthest west ensemble track ) to a nor'easter..

Seems that way. And thanks for the details.

But if the 18z GFS ain't playing along, I'm punting. Next.

Link to comment
Share on other sites

About anything could happen with this system. There's definitely a chance that this system could be blocked from heading too far north. If the storm survives on the models throughout the week, I think it will produce snow a bit further south of this current one.

Link to comment
Share on other sites

That is pretty impressive for them to have it that well defined as far out as that is. Nearly every ensemble member is picking up on something in that time rage. Again remember there is 51 of them.. One cluster is focused on a track towards Chicago, Then there is one over Ohio and then to a lesser extent a cluster near i95.. Spread goes from a track to Duluth ( furthest west ensemble track ) to a nor'easter..

:lol: I guess theres no better place to be 10 days out than in the middle.

Link to comment
Share on other sites

Alright...mentioned the idea of a potential "one-two" type scenario in this general timeframe with one storm tracking rather far NW, and the second storm tracking farther southeast and putting more of this sub-forum into play. The models, especially the Euro are showing this scenario wonderfully right now.

post-525-0-66930800-1355108238_thumb.png

The GFS and Euro ensembles valid Friday morning are in good agreement in bringing a potent piece of energy out of the southwestern US...and both do a good job of showing that while AO/NAO blocking will to some extent will be present, that the polar jet will be running near or north of the US/Canadian boarder. This will significantly limit how much cold this first shortwave has to work with.

This is however, rather expectantly, where the model differences begin to increase significantly:

post-525-0-00778900-1355108604_thumb.png

The GFS ensembles, on the right, shear out the first shortwave, and in response show a much more zonal flow across the central and eastern US Saturday morning. The Euro ensembles are much more in agreement over bringing out the shortwave in one piece and not shearing it out. The GFS suite is also much flatter in the Pacific than the Euro suite and shows much less energy (our potential second storm, assuming there is even a first one this upcoming weekend) diving into the northwest US than the Euro suite.

Interestingly enough, it was the GFS suite that was generally flatter in the Pacific in the medium range prior to the ongoing storm across the Great Lakes/Ohio Valley, however, the synoptic set-up arguably favored a much stronger solution and mis-placement of much smaller scale features is what minimized the potential with this current storm.

When comparing the operational GFS and Euro (12z) valid 0z Saturday/15th, one can see significant differences in handling of polar branch shortwaves, which likely results in the GFS shearing out the shortwave ejecting into the Plains in this timeframe:

post-525-0-62420300-1355109261_thumb.png

The GFS is much more dominant with the polar branch S/W riding through the upper Midwest in this timeframe than the Euro, resulting in the northern wave shearing out the southern wave.

The GFS and Euro also differ in where they place the weak SE US ridging, with the GFS placing it farther east, right along the east coast. Given the -NAO, I'd slightly favor stronger troughing over extreme eastern Canada and the far NE US, allowing ridging to be focused a bit farther west, as the Euro dipicts.

post-525-0-74244900-1355110530_thumb.png

The GFS and Euro suites both show the MJO moving into phase 1 over the coming days...however, I am unsure if this will significantly modulate the Pacific jet, which is fully extended from southeast Asia towards western N. America, as this generally correlates with convection over the Atlantic and Africa...which won't significantly weaken the Pacific jet.

However, the monstor NE Asian vortex, aka a very strong -WPO, is expected to break down in a hurry over the coming days. This should allow ridging south of Alaska to shift towards the Aleutians, and pump very cold air into Alaska and western Canada. The caveat to this is that the GFS and Euro try to move a massive PV towards northern Alaska, and minimize how far north this ridging noses and how far south the cold can come. However, the stratosphere is very warm over this region, which may discourage such a massive tropospheric vortex in that area:

post-525-0-01421300-1355110932_thumb.gif

So all and all...a ton of conflicting signals in this timeframe.

If we can see the Pacific jet relax a little...I'd certainly favor a more significant first storm and second storm idea, with the second storm around the 18th being a potential snow maker. However, it is uncertain how much the Pacific jet will relax, with pros and cons on the field.

As always, smaller details, such as polar branch shortwaves, may also present a fly in the ointment.

So, to surmise, although I'm probably a bit pesimistic on storm chances in this timeframe, I can't conclusively say yet whether or not we'll see a storm or two materialize...or if the threat fizzles.

Link to comment
Share on other sites

Thanks for the write-up. Why has the Pacific jet been raging so much the past couple of years? Do you think Hurricane Sandy messed up our pattern?

Strong -PDO and La Nina last year did us in...this year we haven't really been able to break into a more El Nino like pattern and get convection east of the dateline yet...mainly due to the warm Indian Ocean/-PDO and only neutral warm ENSO. But that's a bit off topic for this thread.

Link to comment
Share on other sites

Strong -PDO and La Nina last year did us in...this year we haven't really been able to break into a more El Nino like pattern and get convection east of the dateline yet...mainly due to the warm Indian Ocean/-PDO and only neutral warm ENSO. But that's a bit off topic for this thread.

2010-11 was a La Nina with a potent -PDO. Matter of fact it was a stronger Nina than 2011-12. Of course good Atlantic blocking in 2010-11 was the great equalizer...along with favorable Aleutian Ridging. We had a terrible Pacific last winter, along with no help from the Atlantic side. All this you know of course, but it wasn't just simply a strong -PDO and Nina that did us in last winter.

Link to comment
Share on other sites

We have potential on the table, all you can ask for so far out with crappy models. GFS, of all things, now shows next Sundays (the 16th) event as suppressed enough to give us snow, not rain....but the storm in the 240-hr timeframe is nonexistent while the Euro has rain here for the 16th but a hell of a storm (including heavy snow for some) after the 228-hr timeframe or so.

Link to comment
Share on other sites

The Euro and GFS ensembles are worlds apart in how they handle the first shortwave (potential weekend storm) and of course the second shortwave (potential 18th-19th storm):

post-525-0-01482300-1355163830_thumb.png

The GFS is known to be too progressive with things, so there's certainly a chance it is too far southeast with the first shortwave.

Link to comment
Share on other sites

System next tue looks pretty sweet on the new Euro. Would probably be a good hit for the STL-LAF-DET corridor. :popcorn:

Euro has had it for several runs. Far too early but if it still has a storm 3-4 days from now then it will instill some confidence in an event in that timeframe.

Link to comment
Share on other sites

Doubt that the storm/s will be on the 00z run! :)..Don't believe anything these models show, especially in the long range!

Agree and disagree... the Euro has been showing both systems in similiar locations for 4 or 5 runs...timing has slowed a bit...

GFS has been swinging and missing in D4 to D8 range...

Either way, models are just flashy brochures for Disney World...Not the same as going there and experiencing it for yourself...

IMO

Link to comment
Share on other sites

Archived

This topic is now archived and is closed to further replies.

  • Recently Browsing   0 members

    • No registered users viewing this page.

×
×
  • Create New...