MJO812 Posted December 18, 2012 Share Posted December 18, 2012 Brett Anderson talking about the euro weeklies. New ECMWF model weeklies have trended colder into eastern Canada and U.S...will post tomorrow a.m. on blog. Link to comment Share on other sites More sharing options...
Guest Pamela Posted December 18, 2012 Share Posted December 18, 2012 It looks like we're going to cool down to near normal for a little while before another major storm heads well to our west. I really do believe that we are still at least a few weeks away from any significant wintry precipitation threats. WX/PT Flipping through the GFS 18z ensemble mean...after the cold front moves through Friday....a pretty reasonably cold period is forecast...I clicked on the remaining images through hour 384 / 850 mb temp and never saw the area get above +2 C. Obviously it does not account for some in between intervals...but I think there is a decent consensus that some moderately cold air will overspread the area into the start of January...and once some cold air is established...doesn't take too much to get some decent measurable snow...even a wave on a stalled front...or some type of weak cyclogenesis to our south. Throw in the fact that you are moving into a more favorable climatological period for snow...and something has to give eventually. Link to comment Share on other sites More sharing options...
MJO812 Posted December 18, 2012 Share Posted December 18, 2012 It looks like we're going to cool down to near normal for a little while before another major storm heads well to our west. I really do believe that we are still at least a few weeks away from any significant wintry precipitation threats. WX/PT GFS and Euro show below normal temps coming up after this weekend. Link to comment Share on other sites More sharing options...
Zir0b Posted December 18, 2012 Share Posted December 18, 2012 GFS and Euro show below normal temps coming up after this weekend. They've been showing that for a month straight... Link to comment Share on other sites More sharing options...
Wxoutlooksblog Posted December 18, 2012 Share Posted December 18, 2012 GFS and Euro show below normal temps coming up after this weekend. After this weekend until the next storm moves into the Great Lakes around the 27th. And then the next shot of cold air behind that system is colder still. We are alternating warm wet & cool dry. But there is nothing close to a pattern that is favorable for east coast snowstorms, nothing, at least not yet. The lower heights on the west coast are largely what causes each storm to hook well to the west of us. WX/PT Link to comment Share on other sites More sharing options...
nzucker Posted December 18, 2012 Share Posted December 18, 2012 All the models, including the 0z ECM, are showing the Alaska ridge developing after the -NAO weakens. That means we'll probably see a favorable period for wintry weather in early January regardless of what the post-Christmas storm does. With the -AO/-EPO being favored, temperatures should average below normal starting this weekend. Link to comment Share on other sites More sharing options...
H2Otown_WX Posted December 18, 2012 Share Posted December 18, 2012 The cut-off the 00z Euro features looks kind of far west given that it has a ridge axis right around Idaho which I always thought was right about where we want it. Just surprising to see such short wavelengths, looks like March. Link to comment Share on other sites More sharing options...
earthlight Posted December 18, 2012 Share Posted December 18, 2012 The GFS continues to break off a significant piece of the Pac ridge over Alaska, and the Euro is beginning to come into agreement. This is a pretty significant development for us. Link to comment Share on other sites More sharing options...
earthlight Posted December 19, 2012 Share Posted December 19, 2012 The medium range guidance is starting to pick up on the effects of the Alaskan ridge breaking off and beginning the changes in the Pac through Central Canada. It is not surprising to see some east shift in the medium-range storm system. Whether or not that storm works out, this feature sets up a great pattern for a system in the first week of January. 12z 12/18: http://www.meteo.psu.edu/~fxg1/ENSHGTAVGNH_12z/f168.gif 00z 12/19: http://www.meteo.psu.edu/~fxg1/ENSHGTAVGNH_0z/f156.gif ^ Notice the dramatic increase in height anomalies over Central Canada and number of members showing a legitimate block forming as a result, in part, of the Pac ridge breaking off over Alaska and shifting east. Link to comment Share on other sites More sharing options...
bluewave Posted December 19, 2012 Share Posted December 19, 2012 The models are indicating a low topped squall threat for early Friday morning across the area. We may see temps rise to around 50 or higher ahead of the storm limiting any surface inversion. This would allow stronger wind gusts of 50 mph or greater to mix down to the surface. Link to comment Share on other sites More sharing options...
nzucker Posted December 19, 2012 Share Posted December 19, 2012 What a dead airmass...still 40F at White Plains in the early morning hours with NW winds in mid-December. Horrible start to winter. Link to comment Share on other sites More sharing options...
nzucker Posted December 19, 2012 Share Posted December 19, 2012 The big system post-Christmas seems to be trending east on all models, so potentially a snow threat here. The blocking looked much stronger on the 0z ECM, and the 6z GFS runs a leading wave ahead of the main system, which depresses heights on the East Coast and sets up a much more favorable track. Very cold air after that system for sure with the -EPO developing. Link to comment Share on other sites More sharing options...
bluewave Posted December 19, 2012 Share Posted December 19, 2012 This December is a textbook example of how the Pacific pattern can dominate our weather despite blocking on the Atlantic side. Link to comment Share on other sites More sharing options...
Weathergun Posted December 19, 2012 Share Posted December 19, 2012 This December is a textbook example of how the Pacific pattern can dominate our weather despite blocking on the Atlantic side. Last December, at this time, the Atlanic side was uglier than Pacific side: Then both the Atlantic and Pacific sides just got worse, the rest of the month. You can tell we weren't going to change things for awhile. Fortunately none of the models are showing that this year. So off this alone, there is more hope for January. Link to comment Share on other sites More sharing options...
Edge Weather Posted December 19, 2012 Share Posted December 19, 2012 18z GFS has some bigtime snow/frozen precip for us on the 27th, with a transfer to the DelMarva, then south of Long Island. It shows a 980mb 50/50 low and a 1036 high over Ontario. The low is 992mb south of Long Island. Over 1 inch of precip, looks to be mostly frozen for Northern New Jersey, and possibly for NYC and Long Island. Link to comment Share on other sites More sharing options...
earthlight Posted December 19, 2012 Share Posted December 19, 2012 The GFS is again stronger with the block splitting off the Pac ridge into Alaska and then Central Canada. Also, with the vort on Christmas trending stronger and sagging the baroclinic zone to the south, the big ULL on the 26/27 can transfer the surface low east more effectively. Link to comment Share on other sites More sharing options...
earthlight Posted December 19, 2012 Share Posted December 19, 2012 Loop through the GEFS H5 height anomalies and watch the block splitting off the Pac Ridge through Alaska and into Central Canada...this is a game changer. Whether it gives us snow with the 12/26 system or not, it's setting the table. http://www.meteo.psu.edu/~fxg1/ENSHGTAVGNH_12z/ensloopmref.html Link to comment Share on other sites More sharing options...
Dsnowx53 Posted December 19, 2012 Share Posted December 19, 2012 The big thing I noticed is that the Christmas vort went a bit south and is having a noticeable effect on the pattern. It suppresses the height field and suppresses the baroclinic zone to the south. It prolongs are NW flow at 500mb as well. Yes there is a strong ridge ahead of the storm initially, but that ridge gets very much squashed by our strong NW flow at 500mb. That was what suppressed 2/6/10. This vort kind of "drags" the flow from the initial ULL that tries to move out, helping that to actually act as a 50/50, forcing redevelopment. Can we be sure this is right? Of course not. But it's something to watch for sure. Link to comment Share on other sites More sharing options...
NaoPos Posted December 19, 2012 Share Posted December 19, 2012 The big thing I noticed is that the Christmas vort went a bit south and is having a noticeable effect on the pattern. It suppresses the height field and suppresses the baroclinic zone to the south. It prolongs are NW flow at 500mb as well. Yes there is a strong ridge ahead of the storm initially, but that ridge gets very much squashed by our strong NW flow at 500mb. That was what suppressed 2/6/10. This vort kind of "drags" the flow from the initial ULL that tries to move out, helping that to actually act as a 50/50, forcing redevelopment. Can we be sure this is right? Of course not. But it's something to watch for sure. Did it @ 0z last night, not the 12z though. That's a pretty key piece to this set up. Link to comment Share on other sites More sharing options...
earthlight Posted December 20, 2012 Share Posted December 20, 2012 About a week after the long discussion regarding the analogs and changes occurring I think we can go back to the board and check out our progress since then. We are now seeing the forecast models indicating a "real" block moving into Central Canada, south of the Davis Straight. This isn't a true NAO block by definition but it's pretty loaded -- a piece splits off a N Atlantic ridge and another off a Pac/Aleutian ridge. The ensembles are showing multiple closed height contours so, if it comes to fruition, it will actually have some teeth to it. In addition, the splitting of this Pac ridge seems to be lighting the match for changes in the Pacific in regards to the EPO. In fact, a good amount of guidance shows a Pac flip to a more favorable state by 5-7 days time. This fits perfectly into the QBO analogs we discussed earlier, which show a mild December and poor pacific giving way to a much improved pattern with more cold on this side of the globe by January. Link to comment Share on other sites More sharing options...
Snow_Miser Posted December 20, 2012 Share Posted December 20, 2012 About a week after the long discussion regarding the analogs and changes occurring I think we can go back to the board and check out our progress since then. We are now seeing the forecast models indicating a "real" block moving into Central Canada, south of the Davis Straight. This isn't a true NAO block by definition but it's pretty loaded -- a piece splits off a N Atlantic ridge and another off a Pac/Aleutian ridge. The ensembles are showing multiple closed height contours so, if it comes to fruition, it will actually have some teeth to it. In addition, the splitting of this Pac ridge seems to be lighting the match for changes in the Pacific in regards to the EPO. In fact, a good amount of guidance shows a Pac flip to a more favorable state by 5-7 days time. This fits perfectly into the QBO analogs we discussed earlier, which show a mild December and poor pacific giving way to a much improved pattern with more cold on this side of the globe by January. John, How do these analogs look going into February and March? Thanks in advance. Link to comment Share on other sites More sharing options...
earthlight Posted December 20, 2012 Share Posted December 20, 2012 John, How do these analogs look going into February and March? Thanks in advance. The pattern generally holds through February with below normal temperatures across a good portion of the CONUS and a very favorable 500mb pattern/anomaly as well. Equal chances by March -- nothing too positively tilted in either direction. Link to comment Share on other sites More sharing options...
CooL Posted December 20, 2012 Share Posted December 20, 2012 http://www.meteo.psu.edu/~fxg1/ENSHGTAVGNH_18z/ensloopmref.html That looks excellent. Aleutian ridge looks like it's going to come roaring back Link to comment Share on other sites More sharing options...
nzucker Posted December 20, 2012 Share Posted December 20, 2012 http://www.meteo.psu...nsloopmref.html That looks excellent. Aleutian ridge looks like it's going to come roaring back The 18z GEFS look pretty cold in the long-range with a block over Central Canada and high heights over Siberia. Link to comment Share on other sites More sharing options...
uncle W Posted December 20, 2012 Share Posted December 20, 2012 The pattern generally holds through February with below normal temperatures across a good portion of the CONUS and a very favorable 500mb pattern/anomaly as well. Equal chances by March -- nothing too positively tilted in either direction. here is the stats for those Febs... year...temp...snowfall max/min temp... 2004....35.0.....0.7".....59 15...ten degrees warmer on average than January... 1985....36.6...10.0".....75 14...eight degrees warmer than January...Cold 1st half... 1980....31.4.....2.7".....57 12...two degrees colder than January... 1971....35.1.......T.......70 6.....eight degrees warmer than January...cold first half... Link to comment Share on other sites More sharing options...
earthlight Posted December 20, 2012 Share Posted December 20, 2012 It's often pretty hard to say what potential outcomes are on the table in the medium to long range -- and the potential post-Christmas storm falls into that category. But I'm becoming increasingly confident that this system is going to have a really, really hard time cutting to our west. The forecast models continue to trend more robust with the block which builds both from the N Atl ridge and a piece of the Pac ridge which traverses Alaska into Central Canada. This is not simply above normal heights -- this is a multiple closed contour blocking ridge. And if the GFS is right, there's a near 50/50 low as well. One way we could get screwed out of this setup, would be a solution similar to the Euro where there is no 50/50...instead the ridge heights actually extend southeast into parts of the Northeast US. Link to comment Share on other sites More sharing options...
earthlight Posted December 21, 2012 Share Posted December 21, 2012 Some hints of a split flow out west now on the medium range guidance. Hard to get too excited about this range...but encouraging nonetheless, especially given how nicely things have followed the QBO analogs to this point. Would be nearly comical to see a big flip in the pattern near the 1st of January as they indicated. But the split flow out west and that big southern stream vort swinging east like some models are showing would be remarkable..especially given the degree of cold air that likely would be available to the north. Link to comment Share on other sites More sharing options...
NaoPos Posted December 21, 2012 Share Posted December 21, 2012 Some hints of a split flow out west now on the medium range guidance. Hard to get too excited about this range...but encouraging nonetheless, especially given how nicely things have followed the QBO analogs to this point. Would be nearly comical to see a big flip in the pattern near the 1st of January as they indicated. But the split flow out west and that big southern stream vort swinging east like some models are showing would be remarkable..especially given the degree of cold air that likely would be available to the north. 0z GFS illustrates this beautifully! Link to comment Share on other sites More sharing options...
earthlight Posted December 21, 2012 Share Posted December 21, 2012 Well, 96 hours out, I think its safe to say that we're looking at the best blocking signal over Central Canada since 2010. Link to comment Share on other sites More sharing options...
Metsfan Posted December 21, 2012 Share Posted December 21, 2012 Well, 96 hours out, I think its safe to say that we're looking at the best blocking signal over Central Canada since 2010. That strong block helps to keep that 50/50 in place also increasing the confluence over southeastern Canada. I would think the Euro will start to catch on to this strong blocking and confluence and shift the storm threat east in the coming runs. Link to comment Share on other sites More sharing options...
Recommended Posts
Archived
This topic is now archived and is closed to further replies.