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Medium/Long Range Discussion Part 2


IWXwx

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Not really sure what the expectations on here are...but I think the change to colder, after this warm period, has remained mid month all along. I wouldn't go looking for any real wintry outcomes, east of the Mississippi, until then. Outside of a thread the needle type event anyway. This especially for those that are rip and reading OP runs out to 10 or 16 days, every six hours. Remain calm, stay the course. 

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Cold air damming. A more popular phenomenon to the east of the Apps.

 

Yeah. I use the term loosely to describe situations where the ageostrophic flow is in place cutting off (or slowing) WAA to the east of the sfc low and keeping an antecedent cold/arctic airmass locked in place. But there's no real geographical impediment to the warmth which I believe is the textbook definition of CAD.

 

edit: locally we do get some microscale damming against the Niagara escarpment, so that's something.

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It is all based on blocking setup. Unlike 2009-10, this one is hitting further west. A flatter pattern would be better like we had. The AO "tanks", but there has to be a ridge somewhere..........

 

So sure, the pattern for the 8-15th will be troughy, but in the west. Hey, that is progress, it is no longer out in the pacific...........

 

Lasts nights 18Z GFS was a classic example of lacking a block..... 

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Meltdown watch issued. Starting Monday - unseeable future.

There is always Feb.

Jk

 

You better be kidding... 

 

The meltdown ends Sunday at noon.... How cold we end up, its anyones guess. 

 

The GFS is being a tad more kind than yesterday, but don't count that Pacific out.

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The GWO analogs eluded to this second warm up all the way back on Dec. 14. It will be short lived with the warmest air being tempered by cooler/colder air arriving in the Jan 15-19 range moving into the Jan 20-25 range with much colder air. Based on GWO and strat. analogs I'm guessing the coldest core of the 850 temps behind the short waves for the Jan 15-19 time frame will remain warmer than -15C then be reinforced with a coldest core of -15 to -25C for Jan 21-25 with a core of cold in the -25 to -30C range possibly as cold as -36C at some point for Jan 25-30. With -33C sneaking over the northern plains or GLKS or NE. Of course the cores of the coldest air will probably remain north of the border but still one can extrapolate what kind of 850 temps would be making down to the central US with those types of 850 temps just north of border.  With shortwaves arriving with more cold air for Jan 24-27 and Jan 27-29 and Feb 1-5. Though it appears the last week of Jan into Feb again would be the coldest air. Of course as stated before the caveat to these is how strong is the southerly flow ahead of these shortwaves that will also produce a spike in temps a day or two before the wave. So a strong wave will have a strong flow and could really spike temps for a day or two before it's arrive too. 

 

 

Actually I made a mistake when forecasting back in Dec. and I hate to flip flop...a big pet peeve of mine but since part of this is in testing stage I had conflicting strat and GWO signals for the 10-13 time frame and I assumed that the strat signal for cold would over whelm the GWO signal for warmth and the cold air would dominate for that time frame. But the GFS seems to be hinting that the GWO will dominate instead for that time frame. Which would change it to warm from Jan 8-10 then a fall in 850 temps for 1 or 2 days after peak in 850 temps then a spike in 850 temps Jan 11-13 which would put us back on track to a fall in 850 temps 1 or 2 days after that which lines up with the Jan 15-19 time cold pocket that I have forecasted previously. I still stand by a shortwave tracking through the central/eastern US although it may be weak Jan 10-11 as I stated last month. Which again since this is still in testing and working out kinks...so the GWO signal that I used that shows up for Jan 8-10 and Jan 11-13 may be a teleconnection that produces pattern (HP cell over the SE) that forces a wave to track west of the Mississippi and into Canada putting the east in a region of strong southerly flow that ends up producing warmer 850 temps. Since both waves for those periods on the GFS appear to stay west of the MS and track northward. 

 

snapback.pngQVectorman, on 14 December 2012 - 04:54 PM, said:

With the newest GWO numbers today the latest analogs indicate a 15-20F warm up in sfc temps Jan 3-Jan 6 compared to prior days highs across Midwest or NE (the Dec. 31-Jan 3 cold episode) and analogs suggest a stair stepped 15-20F temperature fall behind the warm up 1-2 days after that, meaning another spell of colder air Jan 5-8.


I extended my outlook through Jan 8 on Dec. 14. I still feel comfortable with those dates and with the newest GWO analogs and latest 10 and 30 mb temp forecast it appears the time frame between Jan 8-10 will see a warm up over the east with a short wave moving through the east Jan 10-11 with cooler air dropping in behind it for Jan 10-13 across the MW/GLKS and then pockets of cooler air arriving Jan 15-19 time frame for the east followed by a second reinforcement of cooler air Jan 20-24.

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Just like the 18z, the 0z GFS OP is positively craptastic; some light snow in the Upper Midwest and Northern Plains with a low about a week out, then a secondary low looks to try to get going by truncation time too far SE for many.  It might work, but I'm starting to wonder if a big storm will even happen in the region at all.

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Just like the 18z, the 0z GFS OP is positively craptastic; some light snow in the Upper Midwest and Northern Plains with a low about a week out, then a secondary low looks to try to get going by truncation time too far SE for many.  It might work, but I'm starting to wonder if a big storm will even happen in the region at all.

 

The GFS is probably trying to scoot the cold air and storm track to the east too fast. Wouldn't bet on anything beyond the next system coming.

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12z GEM blows up a huge storm late next weekend.  Would be a powerful blizzard for the Dakotas, with a good shot at some decent convection for many of us in the warm sector. 

 

That's the pattern changing storm that the Euro and GFS have been featuring.

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That's the pattern changing storm that the Euro and GFS have been featuring.

 

 

Yeah the LW trough digging in behind that storm is very impressive.  Should yield some major action.  Could be some extreme potential with this setup.  Tremendous cold air waiting to dump down with some unseasonable warmth out ahead of it.  If this evolves the right way this could end up being the storm of the winter for someone.  Gonna be a fun week or two ahead tracking all this.

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The 12z GFS comes close to something big around 120hr and looks like it's going to be but these backside waves look like they interfere and the main ULL jumps northeast really quick causing a positive tilt trof. Need it to really dig and move. 

Even though the operational models are having issues, this is the recipe for something big: 

12zENS6-10day850mbTempAnomalyNA.gif

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