usedtobe Posted December 11, 2011 Share Posted December 11, 2011 Which thread is Don's post in? I looked at the main forum and didn't see it but I didn't dig too deep either. The only thing I have against subforums is that I find myself stuck ours and I miss too much good info. Expecially from HM, Don S, and the usual suspects. It's just the one that says most strong positive ao events % events) lasted for over 40 days here and a thread he did on eastern during the 2009-2010 season on strong negative nao or Ao (I forget which) in which he found that the negative nao usually came back after it broke for a short period. Sorry for misleading you and wasting your time. Link to comment Share on other sites More sharing options...
BethesdaWX Posted December 11, 2011 Share Posted December 11, 2011 To me the low pressure over the lakes at both 850 and the surface suggests that the xmas day storm as it is modeled would probably be rain across dc despite the marginal 850 temps and thickness. That was the reason for the are you trolling comment. Yes, I can remember and Don s stats suggest when the ao is over 4 Sd that the positive AO lasts for 40 days or so. Bob Chill's stats suggest that even when we get a negative ao this winter it might not be long lasting. My guess for a break in the pattern is in Jan. The GFS xmas storm really isn't much of a pattern change. Looks like ZR potential? We haven't had a big ZR storm in awhile. A 1999 redux would be a dream $$$ maker for those of us in the tree business Link to comment Share on other sites More sharing options...
Bob Chill Posted December 11, 2011 Share Posted December 11, 2011 It's just the one that says most strong positive ao events % events) lasted for over 40 days here and a thread he did on eastern during the 2009-2010 season on strong negative nao or Ao (I forget which) in which he found that the negative nao usually came back after it broke for a short period. Sorry for misleading you and wasting your time. There are 2 things that you could never do to me and that is misleading me or wasting my time. I'm probably speaking for the enitire ma subforum (and main board as well) but I totally appreciate the time you spend here and the info you share. Probably some of the most level headed stuff on the board. I struggle understanding the larger scale features of weather but I'm half decent at statistical data analysis. I found Don's posts. The worst thing is that I posted in the same thread and all the good stuff came shortly after and I never revisited. It's too bad our real winter season is so short. Doesn't take much to steal a bunch of it away but it is what it is. Link to comment Share on other sites More sharing options...
Ellinwood Posted December 11, 2011 Author Share Posted December 11, 2011 10pm temps: DCA: 35 IAD: 31 BWI: 30 Gonna be a cold one. Link to comment Share on other sites More sharing options...
WVclimo Posted December 11, 2011 Share Posted December 11, 2011 DP is 14 and temp is down to 33....wonder if I will see my first teen low of the season 23/12 here. Clear skies, calm winds and rising barometer. First teens of the season here for certain tonight. Link to comment Share on other sites More sharing options...
BethesdaWX Posted December 11, 2011 Share Posted December 11, 2011 I have a bunch of garbled notes jotted down and I'm too lazy to dig deep in but I have noticed a couple of things that stand out. Generally speaking, when a sustained ao/nao signal develops (one way or the other) in Nov-Dec it does break during the winter but the break appears to be short lived before going back to the previous pattern. I don't really count spring and summer months when looking at sustained strong + or - patterns. I have generally been looking at nov - dec in particular. The NAO is much more volitile than the AO so usuing the Nov-Dec signal doesn't work out as well as the AO. It's very clear from a purely statistical standpoint that when there is a strong + or - AO index in the Nov-Dec timeframe (especially Dec), it's fairly uncommon for more than one month out of the following Jan-Mar timeframe to have the opposite index. Last year was one of those exceptions. AO was negative from August all the way through January and we all know what happened from Feb on last year. Another thing I've been thinking that is more of a wag than anything else is that the AO was negative a heck of alot more than positive during the 2005 through Jan of 2011. The long term -AO cycle (that I really don't know that much about) could have potentially switched on us in Feb of last year. Don't have a clue if that is right but it sure feels like the possibility of a longer term +AO cycle has started or at least the longer term -AO has ended for the time being. Who knows? Did you take into account when the AO and NAO phase shift began? The phase shift seemed to occur back in August? I think I can see the reason for it though, from my take the NAO represents the climate's stability, where a +NAO represents a more stable state, and a -NAO represents a state reacting to a change in energy levels and/or handling. The NAO correlates almost flawlessly to the Amount Of Change Between Solar Cycles, relative to our distance from equilibrium. When cycles are of similar strength for extended periods, less energy change = +NAO (stable state). More variance from one cycle to the next = -NAO (unstable state). LOL, look at how many moving parts the large scale pattern has during a deep -NAO, while in a +NAO everything seems more uniform. In our +NAO, as solar cycle 24 saw the jump in activity this summer, the difference between cycle 23 and 24 obviously decreased then, while the waker part of 24 had a larger deviation, especially last winter the difference had been huge. It's all about the change in external forcing IMO that determines the NAO state. 1900-1930: Little change in Sun, = +NAO. The next 4 cycles each featured greater variance from their predecessor, more variance each time..and the net NAO trend went down until the 1980 cycle, features less variance from the previous than the 1970 cycle did, but the variance was still large..so the NAO still averaged negative but not as much as before. 1990 cycle had almost no variance and the NAO went positive until it ended, the 2000s cycle featured more variance but still not much..hence a less +NAO. It all works. It's fascinating to see such a great correlation between the amount of change between solar cycles and the NAO index. I think our own position relative to equilibrium matters to though, and the Maunder Minimum featuring no real solar cycles would mean we'd have a long way to cool before reaching a stable state. Link to comment Share on other sites More sharing options...
yoda Posted December 11, 2011 Share Posted December 11, 2011 34/15 at 11 PM at DCA.... looks like the freeze is finally coming for DCA Link to comment Share on other sites More sharing options...
yoda Posted December 11, 2011 Share Posted December 11, 2011 33/17 midnight at DCA... Link to comment Share on other sites More sharing options...
MN Transplant Posted December 11, 2011 Share Posted December 11, 2011 Coolest temp of the season thusfar. Nice chilly one. Link to comment Share on other sites More sharing options...
BethesdaWX Posted December 11, 2011 Share Posted December 11, 2011 Have 28.8, DCA now decides to run just 4 degrees warmer? Thought warm microclimates are supposed become more pronounced in colder nights? (the "kelvin" effect?) Link to comment Share on other sites More sharing options...
Ian Posted December 11, 2011 Share Posted December 11, 2011 dca finally does it. 31 at 1 a.m. Link to comment Share on other sites More sharing options...
CranberryWX Posted December 11, 2011 Share Posted December 11, 2011 Heading for the mid teens tonight Link to comment Share on other sites More sharing options...
WxUSAF Posted December 11, 2011 Share Posted December 11, 2011 About 22F here. Link to comment Share on other sites More sharing options...
Fozz Posted December 11, 2011 Share Posted December 11, 2011 20 degrees here Link to comment Share on other sites More sharing options...
mitchnick Posted December 11, 2011 Share Posted December 11, 2011 meh, as the late, great Jack the Warmanista would have said....."850 temps started warming late yesterday" Link to comment Share on other sites More sharing options...
Midlo Snow Maker Posted December 11, 2011 Share Posted December 11, 2011 meh, as the late, great Jack the Warmanista would have said....."850 temps started warming late yesterday" god this winter is just sucking so far Link to comment Share on other sites More sharing options...
Solo2 Posted December 11, 2011 Share Posted December 11, 2011 19 for a low last night....pretty chilly out there. Link to comment Share on other sites More sharing options...
BethesdaWX Posted December 11, 2011 Share Posted December 11, 2011 bone chilling low of 28 Link to comment Share on other sites More sharing options...
EastCoast NPZ Posted December 11, 2011 Share Posted December 11, 2011 17F at 8AM. Coldest of the season. Link to comment Share on other sites More sharing options...
WinterWxLuvr Posted December 11, 2011 Share Posted December 11, 2011 18.1 for the low. Link to comment Share on other sites More sharing options...
CranberryWX Posted December 11, 2011 Share Posted December 11, 2011 15 for a low after a high of 37 yesterday...first day to stay in the 30s. The sun made it feel warmer though. Link to comment Share on other sites More sharing options...
Stormpc Posted December 11, 2011 Share Posted December 11, 2011 21.0 was low. Temps leveled out in the low 30's till around 11pm then crashed after. Coldest thus far. Link to comment Share on other sites More sharing options...
jonjon Posted December 11, 2011 Share Posted December 11, 2011 Low was 3.9 degrees here. I win Link to comment Share on other sites More sharing options...
EastCoast NPZ Posted December 11, 2011 Share Posted December 11, 2011 Low was 3.9 degrees here. I win Geebus! Do you still have snowcover? I would have thought last night was textbook for inversions. Link to comment Share on other sites More sharing options...
nw baltimore wx Posted December 11, 2011 Share Posted December 11, 2011 Geebus! Do you still have snowcover? I would have thought last night was textbook for inversions. Not far from Jon's B and B. http://www.whitegrass.com/report.html Link to comment Share on other sites More sharing options...
Wonderdog Posted December 11, 2011 Share Posted December 11, 2011 Got to 23 last night. Link to comment Share on other sites More sharing options...
Avdave Posted December 11, 2011 Share Posted December 11, 2011 19* for the low, crisp, cool morning, gorgeous outside Link to comment Share on other sites More sharing options...
MN Transplant Posted December 11, 2011 Share Posted December 11, 2011 27.1. Coldest by 4 degrees. Link to comment Share on other sites More sharing options...
Ian Posted December 11, 2011 Share Posted December 11, 2011 Darn DCA hit 32 at 11:59 p.m. so tied for third latest Link to comment Share on other sites More sharing options...
nw baltimore wx Posted December 11, 2011 Share Posted December 11, 2011 Darn DCA hit 32 at 11:59 p.m. so tied for third latest Do you know the year and least number of December days DCA hit freezing? Looking at the extended models, after tonight and maybe tomorrow, it may be a long while before it happens again. Link to comment Share on other sites More sharing options...
Recommended Posts
Archived
This topic is now archived and is closed to further replies.