usedtobe Posted December 2, 2010 Share Posted December 2, 2010 I wrote this last night mostly before seeing the 00Z nam so it sort of lost it's impact. One thing I didn't discuss because of the forum was the importance of the difference in tilts of the two troughs and how having a negative tilt increases the upper level divergence and lifting which leads to more precipitation and lowering of pressures. http://voices.washingtonpost.com/capitalweathergang/ Link to comment Share on other sites More sharing options...
Kevin Druff Posted December 2, 2010 Share Posted December 2, 2010 One thing I didn't discuss because of the forum was the importance of the difference in tilts of the two troughs and how having a negative tilt increases the upper level divergence and lifting which leads to more precipitation and lowering of pressures. Yay for me! I actually noticed that WITHOUT the hand-holding. Link to comment Share on other sites More sharing options...
usedtobe Posted December 3, 2010 Author Share Posted December 3, 2010 It's good that 300 plus hour forecasts suck so much as the 12Z Friday gfs really looks nina-like with the trough going back in the west and the block shifting enough east to open the floodgates for warmth across the middle of the country. It's probably going to be wrong as it's in strong opposition to the euro weeklies though they also have not been the greatest. I'm of two thoughts, one even when the nao weekens and goes positive during really negative nao periods, it usually tanks a second time. That tendency may be fighting the nina and mjo which would favor the 12Z gfs. I have no confidence in me being able to tell which idea has more weight. I can convince myself of either argument. My gut feeling now is that the gfs will flip to a colder look in that time range at 18Z but ..... Link to comment Share on other sites More sharing options...
mdsnowlover Posted December 3, 2010 Share Posted December 3, 2010 It's good that 300 plus hour forecasts suck so much as the 12Z Friday gfs really looks nina-like with the trough going back in the west and the block shifting enough east to open the floodgates for warmth across the middle of the country. It's probably going to be wrong as it's in strong opposition to the euro weeklies though they also have not been the greatest. I'm of two thoughts, one even when the nao weekens and goes positive during really negative nao periods, it usually tanks a second time. That tendency may be fighting the nina and mjo which would favor the 12Z gfs. I have no confidence in me being able to tell which idea has more weight. I can convince myself of either argument. My gut feeling now is that the gfs will flip to a colder look in that time range at 18Z but ..... Its good that your on this board. I'd rather read your thoughts on weather than continually follow the gfs, no matter what model run is on. Thanks for your contribution to this board. and, of course, eventhough its early, happy holidays to you Wes. Link to comment Share on other sites More sharing options...
usedtobe Posted December 3, 2010 Author Share Posted December 3, 2010 Its good that your on this board. I'd rather read your thoughts on weather than continually follow the gfs, no matter what model run is on. Thanks for your contribution to this board. and, of course, eventhough its early, happy holidays to you Wes. The operational GFS is certainly the outlier as the ensembles have a much colder look and don't drop the low into the southwest or move the atlantic block as far east. The euro 240 hour prog looks frigid but the model has not been good lately and seems to me to have been showing too much amplitude at that time range. Link to comment Share on other sites More sharing options...
usedtobe Posted December 5, 2010 Author Share Posted December 5, 2010 The 192 hour system that showed up on the gfs and euro last night is encouraging for those on the east as there at least is room for a good system on both sets of progs. The euro ensembles also liked having a storm but the mean kept it a little too far inland for most of the south of 40 group to cash in. I didn't check the superensemble analogs to see how many snowstorms showed up, but did note that all ten dates were from the 1950s and 1960s, a period when the negative nao dominating. 5 of the dates were associated with fairly strong la ninas. three of the dates were from 1955-1956, a year when the nao was negative most of the winter once the negative nao got going during the latter half of december, same held for 1954-1955. The other date from 1950-1951 which only had a negative nao during dec and then again in March. All those years had 10-12 inch of snow at dca for the season. I din't check farther north, I'll leave that to Unc w. MY comments about the pattern and the progs show how stupid it sometimes is trying to say what might happen beyond 5 days. The best could can usually do is couch things compared to climo and sometimes you'll still look quite dumb. I didn't like the pattern because of no 50 50 low yesterday, it's still missing today but the models don't seem to care. We'll see. I'd like the pattern if I lived north of PHL. We guys south just have to wait to see whether the euro or GFS idea is best. I ended up looking at the dates spit out by the superensembles and they spit out only one 1" plus event at DCA in the ten dates given. I guess I should also look at IAD and BWI but I don't have their dates. Last year, the superensembles were really good at expressing the potential of the pattern. This will be a good test of them this year Link to comment Share on other sites More sharing options...
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