thunderbolt Posted February 11, 2018 Share Posted February 11, 2018 Is there a difference between a ssw during a la Nina versus a ssw in a El Nino Link to comment Share on other sites More sharing options...
nzucker Posted February 12, 2018 Share Posted February 12, 2018 1 hour ago, thunderbolt said: Is there a difference between a ssw during a la Nina versus a ssw in a El Nino Well, SSWs are more common during El Ninos because the El Nino causes enhanced ozone transport to the North Pole via the Brewer-Dodgson Circulation. Low ozone is a common condition of La Ninas, which makes it harder to warm the stratosphere effectively. Link to comment Share on other sites More sharing options...
thunderbolt Posted February 12, 2018 Share Posted February 12, 2018 1 hour ago, nzucker said: Well, SSWs are more common during El Ninos because the El Nino causes enhanced ozone transport to the North Pole via the Brewer-Dodgson Circulation. Low ozone is a common condition of La Ninas, which makes it harder to warm the stratosphere effectively. Ok thank you for your response Link to comment Share on other sites More sharing options...
Rtd208 Posted February 12, 2018 Share Posted February 12, 2018 Link to comment Share on other sites More sharing options...
Paragon Posted February 12, 2018 Share Posted February 12, 2018 1 hour ago, Rtd208 said: East-based -NAO? Link to comment Share on other sites More sharing options...
Wannabehippie Posted February 12, 2018 Share Posted February 12, 2018 On 2/6/2018 at 3:13 PM, donsutherland1 said: If the vortex splits, that development would more likely favor Eurasian than North America. Still, the GEFS are hinting that the AO could plunge toward the end of the 15-day forecast period, so we'll see what happens. Looks like this is the case. Indexes are holding steady in keeping cold air away from the US east coast (except for some quick shots). Storms will likely go to west of the big cities, giving them rain. I would love to hear Dr. Judah Cohen's latest thoughts though. Link to comment Share on other sites More sharing options...
Rtd208 Posted February 12, 2018 Share Posted February 12, 2018 Link to comment Share on other sites More sharing options...
Rtd208 Posted February 12, 2018 Share Posted February 12, 2018 Link to comment Share on other sites More sharing options...
Rtd208 Posted February 12, 2018 Share Posted February 12, 2018 I would think even if we don't get the snow that with the potential blocking that may develop we should at least see slower moving and more potent storm systems. Correct? Link to comment Share on other sites More sharing options...
Rtd208 Posted February 12, 2018 Share Posted February 12, 2018 Link to comment Share on other sites More sharing options...
donsutherland1 Posted February 13, 2018 Share Posted February 13, 2018 6 hours ago, Wannabehippie said: Looks like this is the case. Indexes are holding steady in keeping cold air away from the US east coast (except for some quick shots). Storms will likely go to west of the big cities, giving them rain. I would love to hear Dr. Judah Cohen's latest thoughts though. I agree. Despite the EPS signal of strong blocking within 10-15 days, caution is likely in order. The EPS performed horribly at a similar timescale, completely missing the current AO+ regime. Link to comment Share on other sites More sharing options...
Rtd208 Posted February 13, 2018 Share Posted February 13, 2018 LOL Link to comment Share on other sites More sharing options...
Rtd208 Posted February 13, 2018 Share Posted February 13, 2018 Link to comment Share on other sites More sharing options...
Rtd208 Posted February 13, 2018 Share Posted February 13, 2018 Link to comment Share on other sites More sharing options...
bluewave Posted February 13, 2018 Share Posted February 13, 2018 https://ams.confex.com/ams/21Fluid19Middle/webprogram/Paper317541.html 12.2 Teleconnection between Madden Julian Oscillation and Sudden Stratospheric Warmings More Thursday, 29 June 2017: 10:45 AM Salon G-I (Marriott Portland Downtown Waterfront) Wanying Kang, Harvard University, Cambridge, MA; and E. Tziperman Recorded Presentation Sudden Stratospheric Warming (SSW) events influence the Arctic Oscillation and mid-latitude extreme weather. Observations show SSW events to be correlated with certain phases of Madden Julian Oscillation (MJO), but the teleconnection mechanism, its planetary wave propagation path and the teleconnection time scale are still not well understood. We study the Arctic stratosphere response to MJO forcing using two models. First, a comprehensive General circulation model (the Whole Atmosphere Circulation Model, WACCM) with standard and enhanced convection entrainment rate leading to stronger MJO. Second, an idealized dry dynamical core with and without idealized MJO-like forcing. We show that the frequency of SSW events increases significantly, and that the averaged polar cap temperature therefore increases significantly in response to stronger MJO forcing. Consistent with previous studies, we find that heat transport by stationary waves is a major contributor to the SSW response. We also find that MJO-forced transient waves propagate at about 70 mb toward the Arctic, and then travel toward the upper stratosphere, then leading to the stationary wave response. The cleaner results possible with the idealized model allow us to identify that the propagation time is of the order of 40-60 days, significantly longer than implied by previous studies. The horizontal propagation path is influenced by zonal jet exit regions, again in agreement with previous studies of remote tropospheric effects of MJO-forced planetary waves. Given that MJO is predicted to be stronger in global warming scenario, these results suggest that SSW events may become more frequent in a future warm climate, possibly with all the implications this has on tropospheric high latitude weather. - Indicates paper has been withdrawn from meeting - Indicates an Award Winner http://onlinelibrary.wiley.com/doi/10.1002/2015GL066984/full Finally, we reexamine the relationship between SST anomalies and MJO activity based on the historical record. Previously, Hendon et al. [1999] showed enhanced MJO activity, both globally and locally in the western/central Pacific, favored by positive SST anomalies in the central Pacific equatorial region around 160°E–160°W during November–March (their Figure 10). Link to comment Share on other sites More sharing options...
Wannabehippie Posted February 14, 2018 Share Posted February 14, 2018 On 2/13/2018 at 7:39 AM, Rtd208 said: Will it be an east based or west based -NAO? Link to comment Share on other sites More sharing options...
Rtd208 Posted February 14, 2018 Share Posted February 14, 2018 Link to comment Share on other sites More sharing options...
AfewUniversesBelowNormal Posted February 15, 2018 Share Posted February 15, 2018 +2000dm heights at 10mb 2-11/12. The record is a 20 period in 1965-66 I think with near +2000 mean I've seen a few Stratosphere warmings and models always go super ridiculous on -NAO 10+ days. I think they don't verify as strong There is a difference in La Nina and El Nina. I found SSWs were much less likely to occur in La Nina but don't remember the effect differences, something like 2.5/1 -NAO likely +15 days but this Winter there is so much mid-latitude warming you have to wonder if it will itself pump the SE ridge in reverse -PNA. probably Link to comment Share on other sites More sharing options...
bluewave Posted February 15, 2018 Share Posted February 15, 2018 According to GEOS/MERRA2, the historical record for eddy heat fluxes (since 1979) was just broken. These represent the waves that help drive the #SSW, which looks to be a record-setting event in a number of ways, at least in the stratosphere. pic.twitter.com/xySyAlwV0r 8:02 AM - 10 Feb 2018 Link to comment Share on other sites More sharing options...
Rtd208 Posted February 15, 2018 Share Posted February 15, 2018 Link to comment Share on other sites More sharing options...
EasternLI Posted April 28, 2018 Share Posted April 28, 2018 Great read explaining this event. Link to comment Share on other sites More sharing options...
MJO812 Posted April 30, 2018 Share Posted April 30, 2018 On 2/13/2018 at 6:44 AM, Rtd208 said: LOL It was very short lived Link to comment Share on other sites More sharing options...
MJO812 Posted April 30, 2018 Share Posted April 30, 2018 On 2/12/2018 at 6:19 PM, Rtd208 said: I would think even if we don't get the snow that with the potential blocking that may develop we should at least see slower moving and more potent storm systems. Correct? We got both =) Link to comment Share on other sites More sharing options...
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