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Met Winter Banter


dmillz25

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That Pac jet really wants to start crashing into the west in the medium to long range. Get ready for a lot of rain and 50s warm sectors for the next month. If that -NAO were to bite this could have been something but alas that went up in smoke. January is looking to come in +5 or better. Hopefully we get a Hail Mary the next six weeks like in 83 when the stars aligned in an otherwise overwhelmed El Niño pattern.

What guidance are you using for your +5 January call?

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6z GFS looks colder with an earlier transfer. Low is stronger and further east than the 0z run. Don't have soundings, but it looks like snow just NW of city.

It actually took a step back with the primary holding on for too long, behind the storm through there's a lot of energy, we'd need decent spacing though for something to amplify. I know it's fun to bittercast, but things look pretty decent till about the 20th, where we go from there will probably depend on whether or not we have a decent SSW event.
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What guidance are you using for your +5 January call?

Mostly the ensembles for general 500mb pattern and I look at all the operational models out to day 10 with heavier weight on the euro and ukmet.

+5 is based on the current positive departure weighed against what I see as normal cold days mixed with some anomalous warm sector days and high lows over the next two weeks and a mild zonal flow to finish January. I think we'll be in the +4-6 range. The blocking never held. Without that the pattern stinks.

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I Think the weekend storm is testimony to the fact of how difficult it is to get an MECS around here and how fortunate we have been over the last decade or so.  Having a 972mb.low at the BM on historically one of the coldest and snowiest days of the year and having to deal with a rainstorm is frustrating..We probably would overcome the WAA from the primary going to the lakes if we had some semblance of a high to drain some cold here down here. At the least we could have ended with a nice thump.

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Larry Cosgrove
 
 
A complex storm threat over the eastern third of the nation may bring some critical changes to U.S. weather starting this weekend. While this will be mainly a moderate/heavy rain event below the Mason-Dixon Line (perhaps some snow and sleet in middle Appalachia), intensification off of the New Jersey coast may enable a cold air draw from Quebec on Saturday PM into Sunday. So a surprise change to snow could occur from the PHL metro into New England. Following this system: an Arctic intrusion for the Midwest and Eastern Seaboard next week.

 

 
 

6z GFS looks colder with an earlier transfer. Low is stronger and further east than the 0z run. Don't have soundings, but it looks like snow just NW of city.

Positive trends from last night. Hopefully it continues today.

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10hpa stratosphere is severely perturbed now in the LR and displacing over Europe.

Today

gfs_Tz10_nhem_1.png

D15

gfs_Tz10_nhem_33.png

Immediate impacts of a displacement would benefit Europe. Mid and longer term impacts are up in the air. My gut tells me a displacement does us no good in this setup; we need a split. However there is a strong correlation between a displaced PV in mid/late January and a -AO for February/March.

More technical explanation provided by Judah Cohen - http://www.aer.com/science-research/climate-weather/arctic-oscillation

Larry Cosgrove  agrees with you

 

I should also mention that there is a huge sudden stratospheric warming event is taking place. By weakening the circumpolar vortex (this time in definitive fashion), chances for widespread blocking in western and northern North America will expand yet again in the last days of January.

 

 
Smile. It's winter.
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Wow some of these are incredibly stupid, I mean really +5 for January SMH. The gfs might've been on to something shortly after the weekend system lifts out.

There's going to be a variety of SW in the pattern that'll make them difficult to pinpoint by the models. Just because things haven't been going your way doesn't mean every post should scream "bust" on everything.

Until it's March 1st with nothing on the horizon, calling it quits now is foolish.

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For what seems to be the third or fourth time in the past 30 days, rumors are again flying about an imminent Sudden Stratospheric Warming (SSW) event. If the past rumors are representative, discussion that the polar vortex will split at the stratospheric level may also proliferate. So far, only a minor stratospheric warming has occurred and the stratospheric polar vortex has not split.

 

As with the earlier speculation, a large dose of caution is required.

 

First, as noted previously, the argument that upward propagating Rossby waves trigger SSW events is an oversimplification. Most such waves do not trigger SSW events. Only a few—about one every two winters—coincide with such events. I use the word “coincide,” because it is not clear from the literature whether the waves or waves coupled with antecedent conditions trigger such events. The literature suggests the latter e.g., one such proposed antecedent condition is a solar minimum. Eastward propagating “Wave 2” is particularly important.

 

For reference, prior to the January 2009 SSW, Wave 2’s amplitude rose well above 60 m/s:

 

strat01122016_3.jpg

Source: Correction to “First simulations with a whole atmosphere data assimilation and forecast system: The January 2009 major sudden stratospheric warming.

 

Second, such events can be top-down (starting at the highest levels of the stratosphere) or bottom-up (usually a response to deep blocking that has preceded it).

 

Third, because predictability of SSW events is poor beyond even 5 days, 360-hour forecasts are highly speculative.  In short, just as one can’t have much confidence that such an event will occur near the end of January, one can’t rule out such a possibility either. Until one gets within a few days of the possible event, one can’t have confidence. In terms of predictability, the literature suggests that the timeframe for reasonably accurate forecasting is “several days in advance.”

 

So far, perhaps in response to two strong wave fluxes (wave 1 and the more important, wave 2), the stratospheric polar vortex was displaced and a minor warming event occurred from 5 mb and upward. Much of the stratosphere has remained very cold. Over the next 240 hours, little changes are expected in terms of stratospheric temperatures.

 

New geopotential waves are forecast to be emerging in the extended range. Wave 1 is forecast to develop somewhat to the south of the most recent flux and at a somewhat lower level of the stratosphere. Wave 2 is forecast to develop somewhat to the north of the prior event and also at somewhat of a lower level of the stratosphere. The development of Wave 2 will need to be watched in terms of amplitude and temperature. However, at least through 240 hours, the forecast amplitude of Wave 2 does not approach levels seen during the January 2009 SSW.

 

For now, some degree of watching is warranted. It is premature to conclude that an SSW event is likely given the forecasts to date and the limited horizon for accurate forecasting. The failed prior forecasts for SSWs from earlier this winter (December and January) and also repeated failed forecasts for the stratospheric polar vortex to split provide a vivid reminder that overconfidence in stratospheric forecasting can be hazardous.  Nevertheless, “swings for the fences” remain all too common.  IMO, given the literature on such events, caution until there is a strong body of evidence within a workable forecasting horizon, is the more prudent approach.

 

If a true SSW occurs, one should see temperatures rise sharply throughout much or all of the area bounded by 60°N-90°N from 30 mb and upward. Moderate or minor warming events would lead to less coverage of warm anomalies in that region and less pronounced warming. If an SSW occurs, then one would next have to see if it propagates downward. Moreover, a few days prior to the event, one would likely see the forecast Wave 2 amplitude approach or exceed 40 m/s.

 

Stratospheric Temperatures:

Strat01122016_2.jpg

 

Strat01122016_1.jpg

 

strat01122016_4.jpg

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Comparing gfs 06z hour 102 with 00z hour 108, I find it interesting, on 06,.the low in ocean went further south east,while the inland low went further north and west.

Then comparing the 00z, the inland low went closer to coast and the low in ocean went closer to coast.

Seems there's playing opposites.

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Comparing gfs 06z hour 102 with 00z hour 108, I find it interesting, on 06,.the low in ocean went further south east,while the inland low went further north and west.

Then comparing the 00z, the inland low went closer to coast and the low in ocean went closer to coast.

Seems there's playing opposites.

That's why it's a step in the wrong direction, if that first storm can stay further SE and die out quickly as the coastal takes over(no further than southern Ohio) then this can be a great for our NW posters, the changes needed for the coast are probably out of reach.
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06z gefs, would appear on the esemble member pressure mode, that the ocean low absorbs the inland low at forecast hour 96, or off of south Carolina coast, coming north east, would seem temperatures are just too warm till hour 120, but I'm pretty sure by then it's too late

Do apologize, using my Android phone with Swype so I'll try to keep spelling errors etc to a minimum.

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