PB GFI Posted November 28, 2014 Share Posted November 28, 2014 The key with those MJO forecasts will be getting a strong enough push into 8 with some amplitude. The Euro forecasts heading for the COD side of 8 would probably mean that the pattern would become less bad mid-month and not necessarily great. We want to see a robust push into 8 like we saw in the recent El Nino Decembers of 2002 and 2009. A turn into COD instead of stronger 8 would probably mean that we could see a moderate snow event sometime between December 19-31. But the chance of getting a major snowfall of 6" or more would be lower unless later Euro runs bring the MJO wave with more amplitude into 8 like we saw in 2002 and 2009. 200210.phase.90days.gif.small.gif 200910.phase.90days.gif.small.gif Yeh def wana see more amplitude like NCEP s . There are some euro members that bring it all the way thru in it`s LR so hopefully that pic gets clearer as we get closer . Link to comment Share on other sites More sharing options...
wkd Posted November 28, 2014 Share Posted November 28, 2014 The weather does not have a memory...all evidence to the contrary nonwithstanding. My sentiments exactly. This is why it annoys me when people invoke climatology as a factor in individual storms. Link to comment Share on other sites More sharing options...
Juliancolton Posted November 28, 2014 Share Posted November 28, 2014 A somewhat false statement considering that soil moisture is an effective medium range forecast tool- as per CPC. What is soil moisture and its self reinforcing tendency than a sort of 'storm track memory'? Personally, the recurring Low track over the Great Lakes towards James Bay/Ungava has me considering the potential of a continuing +NAO... There's a reason why persistence forecasting is largely obsolete in the mid-latitudes... Link to comment Share on other sites More sharing options...
Jaguars Posted November 28, 2014 Share Posted November 28, 2014 A warm up is inevitable as MJO moves through phases 4-6. And like DT said, even if MJO enters phase 7 around DEC11 give it a few days for changes in CONUS...so DEC 15-18 looks to be good. With that said....12z GFS 500 mb anomalies Nice. If memory serves, didn't Euro & GFS consistently try and warm up mid to long ranges last winter after week or so long cold periods only to then time after time back them down? And then ultimately would go basically zonal followed by a reloaded cold regime in Eastern CONUS? Or am I just suffering from cold biased dementia? Link to comment Share on other sites More sharing options...
SnoSki14 Posted November 28, 2014 Share Posted November 28, 2014 Such a warm look on the ensembles as we approach mid month. It's definitely troublesome given seemingly more favorable signals from the MJO and EPO. It only leads to me believing it might take until post 12/20 for colder air to work in. Link to comment Share on other sites More sharing options...
PB GFI Posted November 28, 2014 Share Posted November 28, 2014 Such a warm look on the ensembles as we approach mid month. It's definitely troublesome given seemingly more favorable signals from the MJO and EPO. It only leads to me believing it might take until post 12/20 for colder air to work in. Dude its 1 ish warm week - ( week 2) . Calm down . The warm ups have been getting muted in the LR .You are not getting wire to wire cold . Yesterday you wanted to PUNT December . I guess its a good sign today that you only want to S% can 3 weeks . Link to comment Share on other sites More sharing options...
SnowGoose69 Posted November 28, 2014 Share Posted November 28, 2014 Yeah, we need the MJO to push into 8 with amplitude during an El Nino December or we end up like 82 and 94 where the +EPO runs the table. 198210.phase.90days.gif.small.gif 199410.phase.90days.gif.small.gif Even if it does not make phase 8 odds are this December would not be anything like 82 and 94, those Decembers simply had no arctic air to be found in Canada at all. Link to comment Share on other sites More sharing options...
uncle W Posted November 28, 2014 Share Posted November 28, 2014 Even if it does not make phase 8 odds are this December would not be anything like 82 and 94, those Decembers simply had no arctic air to be found in Canada at all. there was some arctic air in December 1982 around the 12th...It was brief and came with some snow...1994 had no such intrusion... Link to comment Share on other sites More sharing options...
Jaguars Posted November 29, 2014 Share Posted November 29, 2014 That's the operational GFS 384 and not the ensemble mean. The ensemble mean has a milder look like the Euro ensembles.. Gotcha Link to comment Share on other sites More sharing options...
stadiumwave Posted November 29, 2014 Share Posted November 29, 2014 That's the operational GFS 384 and not the ensemble mean. The ensemble mean has a milder look like the Euro ensembles. Spoke to soon my friend. Link to comment Share on other sites More sharing options...
Neblizzard Posted November 29, 2014 Share Posted November 29, 2014 Spoke to soon my friend. If anyrhing that looks like a strong El Niño with higher than normal heights over the plains and lower than normal heights over the south. They have been very inconsistent in the 11-15 day range. Link to comment Share on other sites More sharing options...
Isotherm Posted November 29, 2014 Share Posted November 29, 2014 Everything going as planned thus far. Perturbations to the stratospheric vortex should continue in early December as the Gulf of Alaskan trough / Russian high pattern resumes, enabling more effective upward propagation of tropospheric waves. As per Judah Cohen's research, vertical wave activity flux anomalies generally exceed 0.16 m2/s-2, upwards of 0.28, approximately 1-2 weeks prior to vortex displacement and splitting events. Current conditions indicate that poleward heat flux at 100mb has surged over 20 K m/s. This is significant, and even though we're seeing a slight lessening of WAF now, I expect that this isn't a "failed" event, and Cohen's research dictates a continued attack of the stratospheric vortex. One would anticipate a stratospheric warming event probably in the first half of December. With regards to the troposphere, most of my winter-outlook analogs featured quite a bit of variance, with the "Warmest" cases finishing around near normal along the East Coast for December. The northern plains might have a tendency to torch for the early/mid part of the month given analogs and current guidance, but we'll see. Analyzing tropical forcing, December of 2003 had a MJO progression that was predominately unfavorable, through phases 3-7: Even given poor tropical forcing, the month was not a blowtorch for the East. Rather, temperatures ended up near normal: 1979 had a similar USA temp orientation; however, the MJO wave was much weaker through phases 3-7. This month looks to feature a more amplified MJO wave, which may or may not make it to phase 8. My point is that even IF it fails to do so, similar past regimes have shown that December will not be a blowtorch or even much warmer than normal for the East. We may even end up colder than normal, especially if the wave is more amplified and progresses quickly into phase 7-8. The precursor tropospheric pattern for stratospheric warming events is also a rather benign one for the CONUS, another reason why the first half of December may not be too wintry. Going forward, all the pieces continue to come together in terms of the SAI/-QBO/+ENSO induced strong WAF / stratospheric perturbation, as well as the tropospheric +ENSO/+PDO/-EPO pattern in the means. Link to comment Share on other sites More sharing options...
Isotherm Posted November 29, 2014 Share Posted November 29, 2014 This month's WAF activity mirrors quite closely November of 1996, one of the few early SSW cases. Note the striking similarity in timing w/ the poleward heat flux in the latter part of November. 2014: 1996: The AO in 1996 turned consistently strongly negative by the second week of December, and persisted about 5 weeks, through mid January. Obviously timing won't be identical, but 1996 might be a good analog as far as stratospheric progression. If correct, we could potentially see a more strongly negative AO initiating in approximately 10-14 days (assuming things progress as planned with continued perturbation). The ECMWF control shows the 'potential' in the future w/ a tanking AO post December 9th, and the ECMWF ensemble mean has been gradually trending more negative in the longer term. Link to comment Share on other sites More sharing options...
NEG NAO Posted November 29, 2014 Share Posted November 29, 2014 This month's WAF activity mirrors quite closely November of 1996, one of the few early SSW cases. Note the striking similarity in timing w/ the poleward heat flux in the latter part of November. 2014: 1996: The AO in 1996 turned consistently strongly negative by the second week of December, and persisted about 5 weeks, through mid January. Obviously timing won't be identical, but 1996 might be a good analog as far as stratospheric progression. If correct, we could potentially see a more strongly negative AO initiating in approximately 10-14 days (assuming things progress as planned with continued perturbation). just hope the snowfall total is not just like 1996 - a Trace of snow in NYC in December and 10 inches total for the season http://www.erh.noaa.gov/okx/climate/records/monthseasonsnowfall.html Link to comment Share on other sites More sharing options...
PB GFI Posted November 29, 2014 Share Posted November 29, 2014 Tom great piece . I actually think the GFS MJO amplified look has the UKMET and adjusted Euro bias MJO on its side They all take it into 7 8 . I think there is some good agreement there Link to comment Share on other sites More sharing options...
Absolute Humidity Posted November 30, 2014 Share Posted November 30, 2014 just hope the snowfall total is not just like 1996 - a Trace of snow in NYC in December and 10 inches total for the season http://www.erh.noaa.gov/okx/climate/records/monthseasonsnowfall.html There's a Cohen interview thread on the main page that may address that very concern. Apparently a strong persistent low has developed in NW Asia that is weaking the SAI SCE strat warming response and Cohen says this feature is more typical with low SAI SCE years and will be destructive for any SSW if this low continues to persist. Thoughts? Link to comment Share on other sites More sharing options...
stadiumwave Posted November 30, 2014 Share Posted November 30, 2014 There's a Cohen interview thread on the main page that may address that very concern. Apparently a strong persistent low has developed in NW Asia that is weaking the SAI SCE strat warming response and Cohen says this feature is more typical with low SAI SCE years and will be destructive for any SSW if this low continues to persist. Thoughts? Read that & has definitely alarmed me. Link to comment Share on other sites More sharing options...
Isotherm Posted November 30, 2014 Share Posted November 30, 2014 Tom great piece . I actually think the GFS MJO amplified look has the UKMET and adjusted Euro bias MJO on its side They all take it into 7 8 . I think there is some good agreement there Thanks Paul! There's a Cohen interview thread on the main page that may address that very concern. Apparently a strong persistent low has developed in NW Asia that is weaking the SAI SCE strat warming response and Cohen says this feature is more typical with low SAI SCE years and will be destructive for any SSW if this low continues to persist. Thoughts? We need to monitor forecasts to see if it actually occurs as current runs suggest (prior runs did not have a NW Asian low). However,even if this trough does retrograde into NW Asia, model consensus is for it to be a transient feature. ECMWF ensemble mean has the low in NW Asia D 2-5, then the pattern reverses post D7 to a Scand / NW Asia ridge and Siberian mid level trough. My take is we're looking at a temporary relaxation in stratospheric perturbation in the short term, but the attack will return quite strong in the medium range and beyond. Link to comment Share on other sites More sharing options...
jdrenken Posted November 30, 2014 Share Posted November 30, 2014 One must also not forget the direct correlation between the MJO and lag for SSW. Link to comment Share on other sites More sharing options...
MJO812 Posted November 30, 2014 Share Posted November 30, 2014 Latest TelliesPNA is still forecasted to risehttp://www.cpc.ncep.noaa.gov/products/precip/CWlink/pna/pna.shtmlAO looks like it will fall into the negative category with some members in the positive categoryhttp://www.cpc.ncep.noaa.gov/products/precip/CWlink/daily_ao_index/ao.sprd2.gifNAO has mixed signalshttp://www.cpc.ncep.noaa.gov/products/precip/CWlink/pna/nao.sprd2.gif Link to comment Share on other sites More sharing options...
Isotherm Posted November 30, 2014 Share Posted November 30, 2014 Other important points to consider are the following: 1. We don't necessarily need a SSW to induce a blocky / negative AO tropospheric pattern. Stratospheric temperatures at 70mb finished warmer than normal for November (which, as noted in my winter discussion, provides a high probability that the AO will average negative in the ensuing DJF period). Perturbation of the stratospheric vortex has been consistent for the past several weeks as evidenced by the surge in wave activity flux anomalies since November 20th to near record daily levels. The stratosphere is warm and the vortex is currently experiencing a near split at various levels. While the vortex will recover in the short-term, what has already transpired (tropospheric-->stratospheric wave activity) will aid in inducing a negative AO by the second week of December. Tropospheric forcing mechanisms like Pacific tropical convection progression should become more favorable as well in a couple weeks. 2. The north Pacific pattern may prevent the realization of a widespread cold CONUS regime for at least the first half of December. While the AO likely will become increasingly negative in the second week of December, temperatures may not respond immediately until retrogression of the GOA low into the Aleutians occurs. Assuming we see that feature resume by mid December, we will see the CONUS temperature pattern follow suit. 3. The upcoming week will not be all that warm for the northern tier due to the current -EPO episode, which promotes strong arctic surface highs near the Canadian border. Warm-ups will be transient through Dec 7th in the Northeast, with the potential for some interior Northeast wintry precip later this week via overrunning of the cold high. 4. The peak / climax of the potential torch period for the CONUS could occur Dec 6th-16th given the EPO transition positive via the lowering of heights near the BC west coast. This should allow mild-maritime Pacific flow for at least a week in December. All the while, the AO will likely be negative as the EPO turns positive. This will dump the cold into Asia for the time being. Keep in mind the EPO is generally a more important teleconnector for temperatures in the CONUS than the AO. A +EPO/ -AO combination tends to be a milder one at this time of year. This is why the retrogression of the GOA trough into the Aleutians is key, regardless of the AO state going forward, the latter of which should be predominately negative (good news). Link to comment Share on other sites More sharing options...
Isotherm Posted November 30, 2014 Share Posted November 30, 2014 And we may have to be patient as it could take a while to get the cross polar flow reestablished once all the cold shifts over to Asia early this month. So even if telecos gradually improve, we could be looking at mostly stale cold air until that cold in Asia can be tapped. Agree. My guess at this point is that the real "onset" to persistent winter conditions as a whole in the CONUS could occur sometime in the second half of the month, potentially by the 20th or thereafter. At this point though, I wouldn't be forecasting torch type departures for the East Coast, and as noted above, I could see a finish similar to 2003/1979 with near normal values here w/ a torchy northern plains, depending upon the timing of the pattern shuffling. Link to comment Share on other sites More sharing options...
uncle W Posted November 30, 2014 Share Posted November 30, 2014 December 1979 started out with a very positive AO... 1979 11 29 1.0101979 11 30 2.7801979 12 1 4.5931979 12 2 5.0401979 12 3 4.5801979 12 4 4.4531979 12 5 4.8001979 12 6 3.9161979 12 7 2.8141979 12 8 3.1851979 12 9 3.2121979 12 10 3.085 nao... 1979 11 29 0.4521979 11 30 1.0451979 12 1 1.4571979 12 2 1.7081979 12 3 1.4251979 12 4 0.9871979 12 5 0.5791979 12 6 0.1471979 12 7 0.1421979 12 8 0.5761979 12 9 0.7321979 12 10 0.8111979 12 11 0.632 pna... 1979 11 28 0.7841979 11 29 0.8871979 11 30 0.7281979 12 1 0.8251979 12 2 0.3371979 12 3 0.0541979 12 4 -0.1011979 12 5 -0.4601979 12 6 -0.5331979 12 7 -0.5011979 12 8 -0.6311979 12 9 -0.8131979 12 10 -0.9941979 12 11 -1.156 epo... 1979 11 30 -85.371979 12 01 62.771979 12 02 129.461979 12 03 63.331979 12 04 65.521979 12 05 34.691979 12 06 -3.461979 12 07 -25.581979 12 08 -57.971979 12 09 -109.011979 12 10 -152.041979 12 11 -190.451979 12 12 -198.041979 12 13 -225.641979 12 14 -254.261979 12 15 -299.481979 12 16 -226.241979 12 17 -90.471979 12 18 -8.361979 12 19 30.641979 12 20 69.001979 12 21 119.781979 12 22 142.231979 12 23 148.191979 12 24 237.001979 12 25 330.551979 12 26 309.001979 12 27 218.311979 12 28 125.28 in 1979-80 there were wild swings in the epo all winter...The AO was at near record high levels...pna was positive going to negative...the nao was mostly positive...This year the AOis negative so far...the nao is positive...the pna is forecast to go positive... Link to comment Share on other sites More sharing options...
Weathergun Posted November 30, 2014 Share Posted November 30, 2014 The key with those MJO forecasts will be getting a strong enough push into 8 with some amplitude. The Euro forecasts heading for the COD side of 8 would probably mean that the pattern would become less bad mid-month and not necessarily great. We want to see a robust push into 8 like we saw in the recent El Nino Decembers of 2002 and 2009. A turn into COD instead of stronger 8 would probably mean that we could see a moderate snow event sometime between December 19-31. But the chance of getting a major snowfall of 6" or more would be lower unless later Euro runs bring the MJO wave with more amplitude into 8 like we saw in 2002 and 2009. 200210.phase.90days.gif.small.gif 200910.phase.90days.gif.small.gif Yeah, we need the MJO to push into 8 with amplitude during an El Nino December or we end up like 82 and 94 where the +EPO runs the table. 198210.phase.90days.gif.small.gif 199410.phase.90days.gif.small.gif Today's forecast GEFS well into phase 8 and EC ENS only in the COD. Even father apart. Although if the EC was correct, I still strong +PDO this year would still support an Aleutian low, -EPO/+PNA. 1984 had a weak +PDO and 1994 had a strong -PDO: Link to comment Share on other sites More sharing options...
Isotherm Posted November 30, 2014 Share Posted November 30, 2014 December 1979 started out with a very positive AO... 1979 11 29 1.0101979 11 30 2.7801979 12 1 4.5931979 12 2 5.0401979 12 3 4.5801979 12 4 4.4531979 12 5 4.8001979 12 6 3.9161979 12 7 2.8141979 12 8 3.1851979 12 9 3.2121979 12 10 3.085 nao... 1979 11 29 0.4521979 11 30 1.0451979 12 1 1.4571979 12 2 1.7081979 12 3 1.4251979 12 4 0.9871979 12 5 0.5791979 12 6 0.1471979 12 7 0.1421979 12 8 0.5761979 12 9 0.7321979 12 10 0.8111979 12 11 0.632 pna... 1979 11 28 0.7841979 11 29 0.8871979 11 30 0.7281979 12 1 0.8251979 12 2 0.3371979 12 3 0.0541979 12 4 -0.1011979 12 5 -0.4601979 12 6 -0.5331979 12 7 -0.5011979 12 8 -0.6311979 12 9 -0.8131979 12 10 -0.9941979 12 11 -1.156 epo... 1979 11 30 -85.371979 12 01 62.771979 12 02 129.461979 12 03 63.331979 12 04 65.521979 12 05 34.691979 12 06 -3.461979 12 07 -25.581979 12 08 -57.971979 12 09 -109.011979 12 10 -152.041979 12 11 -190.451979 12 12 -198.041979 12 13 -225.641979 12 14 -254.261979 12 15 -299.481979 12 16 -226.241979 12 17 -90.471979 12 18 -8.361979 12 19 30.641979 12 20 69.001979 12 21 119.781979 12 22 142.231979 12 23 148.191979 12 24 237.001979 12 25 330.551979 12 26 309.001979 12 27 218.311979 12 28 125.28 in 1979-80 there were wild swings in the epo all winter...The AO was at near record high levels...pna was positive going to negative...the nao was mostly positive...This year the AOis negative so far...the nao is positive...the pna is forecast to go positive... Yeah, 1979 will probably be warmer than this December given the AO was strongly positive (+1.2). 2003's AO averaged near neutral for December, and the AO forecast going forward is generally negative in the longer term, so the 2003 December temperature departure finish of near normal is likely toward the "warmer end" of the spectrum for our results locally. I highly doubt we see a warmer / much warmer than normal December in the final tally. Link to comment Share on other sites More sharing options...
PB GFI Posted November 30, 2014 Share Posted November 30, 2014 Yeah, 1979 will probably be warmer than this December given the AO was strongly positive (+1.2). 2003's AO averaged near neutral for December, and the AO forecast going forward is generally negative in the longer term, so the 2003 December temperature departure finish of near normal is likely toward the "warmer end" of the spectrum for our results locally. I highly doubt we see a warmer / much warmer than normal December in the final tally. Great disco in NE with regards to Cohen. Mid Dec to mid Feb would b epic. Link to comment Share on other sites More sharing options...
Isotherm Posted November 30, 2014 Share Posted November 30, 2014 Great convo in NE with regards to Cohen. Mid Dec to mid Feb would b epic It would be nice if we could time the conducive pattern / high latitude blocking episode with our best period climatologically, namely Dec 20-Feb 20 as you said. 2010-11 was one of my favorite winters not only b/c of the snowfall but the excellent timing. It's probably better that we didn't lock in a strongly -NAO/AO pattern beginning in late Nov/now, as historically, we'd likely hold the regime for 60 days maximum, and consequently break down near the end of January. If we can initiate the sustained blocking regime in late December, we have a chance to hold it through most of the rest of meteorological winter, before the vortex re-intensifies/cools again. Link to comment Share on other sites More sharing options...
PB GFI Posted November 30, 2014 Share Posted November 30, 2014 It would be nice if we could time the conducive pattern / high latitude blocking episode with our best period climatologically, namely Dec 20-Feb 20 as you said. 2010-11 was one of my favorite winters not only b/c of the snowfall but the excellent timing. It's probably better that we didn't lock in a strongly -NAO/AO pattern beginning in late Nov/now, as historically, we'd likely hold the regime for 60 days maximum, and consequently break down near the end of January. If we can initiate the sustained blocking regime in late December, we have a chance to hold it through most of the rest of meteorological winter, before the vortex re-intensifies/cools again. That's why I said earlier no one like to punt 2 weeks of a 12 to 16 week pattern but the slivers I'm ok giving up are first 15 and the last 15. Getting the physical drivers to coalesce during the middle 60 makes those winters memorable Link to comment Share on other sites More sharing options...
Stormlover74 Posted November 30, 2014 Share Posted November 30, 2014 OT but the last time I traveled over Christmas was 2002. This year I'm supposed to be in NC from the 22nd-26th. I expect something will happen that week Link to comment Share on other sites More sharing options...
Weathergun Posted November 30, 2014 Share Posted November 30, 2014 A +PDO doesn't always translate into a strong -EPO pattern here in December. December 86-87 featured a strong +PDO but the EPO remained positive. One way or another, we'll need a retrogression of the Aleutian Low later this month for a more favorable pattern to begin to develop. 500.png We still have deep negative height anomaly over Aleutians. It looks we wind up with fast flow and pacific air flooding over the CONUS with +NAO. Link to comment Share on other sites More sharing options...
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