frd Posted December 8, 2019 Share Posted December 8, 2019 8 minutes ago, EastonSN+ said: The positive EPO is showing up here with a negative PNA. However, not the worst pattern we have seen as the NAO heads to almost neutral and the AO heads to slightly below neutral. Cold air would be lacking however if we can get a storm to cut underneath and strengthen like the last storm, with it being later in the year perhaps a bit of a better result. Any recent changes on your opinion for later in the month ? Are you still ( and hopefully I am recalling correctly ) more hopeful about a more conducive pattern for Jan. into Feb? Wonder if we ever get an "ideal " pattern ? Very difficult to have both a favorable Pac and Atlantic at the same time. Link to comment Share on other sites More sharing options...
uncle W Posted December 8, 2019 Share Posted December 8, 2019 10 minutes ago, frd said: Really interesting how this post 12/20 warm up seems to happen more frequently the last several years. Maybe this year will be a exception, but as you mention, the MJO progression increases the odds that it might occur yet again. we have to hope the ao and nao picks up the slack... 1 Link to comment Share on other sites More sharing options...
hudsonvalley21 Posted December 8, 2019 Share Posted December 8, 2019 11 minutes ago, SnowGoose69 said: It seems there is rarely an issue with these events as far as getting snow. Either they end up all snow once the FROPA occurs or the wave never develops at all and it’s all rain. There’s always a scare in the few hours preceding it where places like SWF/HPN/FWN are like 34/24 and the city is still 42/34 but inevitably the cold air makes it in. I always find these things to be all similar like most SWFEs are. If they happen it’s generally a good 2-6 inch type event with only a small percentage of them falling below or above that range 12 z NAM is showing that. But you know the NAM is definitely out to far now. We'll keep on watching the trends. Link to comment Share on other sites More sharing options...
MJO812 Posted December 8, 2019 Share Posted December 8, 2019 2 minutes ago, uncle W said: we have to hope the ao and nao picks up the slack... They look good this morning Link to comment Share on other sites More sharing options...
frd Posted December 8, 2019 Share Posted December 8, 2019 2 minutes ago, bluewave said: This seasonal pattern of warming around the solstice has been remarkably consistent. NYC has made it above 50 degrees every year since 2011. That is what I thought, but some folks deny it is really a pattern, due to the limited years. Personally, I am a believer, maybe the recent global warming , such as warming in the West Pac might be to blame, but the timing is remarkable. The timing issue around the solstice is the most intriguing element here. Link to comment Share on other sites More sharing options...
uncle W Posted December 8, 2019 Share Posted December 8, 2019 warmest Christmas days.... year...max/min 1889....64 43 snowy March... 1893....58 45 Snowy February... 1900....59 44 1915....55 38 snowy March... 1932....59 47 snowy February... 1933....55 34 snowy February 1936....56 40 1940....62 38 snowy March... 1964....60 49 snowy January... 1965....59 47 snowy January... 1979....61 50 March snow... 1982....64 41 snowy February... 1986....53 43 snowy January... 1987....53 48 snowy January... 1988....53 37 1994....59 41 February snow only... 2005....54 39 big Feb. Snow... 2008....57 33 March snow... 2014....62 44 50" snow season... 2015....66 57 big January snow... 2016....50 36 Feb March snows... Link to comment Share on other sites More sharing options...
White Gorilla Posted December 8, 2019 Share Posted December 8, 2019 1 hour ago, purduewx80 said: The battle between Tuesday's near-record warmth and the influx of Arctic air from the Lakes Wednesday will lead to an impressive jet streak across the Northeast. This kind of jet structure can lead to a band of moderate-heavy precipitation that would be our best bet for a few inches of wet snow Wednesday morning. NAM and GFS both showing a 170-190KT wind max between 200-300mb: Most of the forecast soundings suggest we go from rain to a wintry mix (IP and FZRA) over to snow, but we may not know exactly what transpires for another day or two. Sorry if this is a stupid question, but could you please explain how higher velocity jet enhances precipitation? I understand that the high temperature contrast would lead to higher wind velocity in the jet stream, but how does that translate into enhanced lift? Link to comment Share on other sites More sharing options...
hudsonvalley21 Posted December 8, 2019 Share Posted December 8, 2019 1 minute ago, bluewave said: NAM ratios in NYC look like 6:1. But the colder surfaces can pick up a few inches if it snows hard enough. The 10:1 ratios more than likely won't happen with this type of system. This will probably come down to a now casting event. Link to comment Share on other sites More sharing options...
SnowGoose69 Posted December 8, 2019 Share Posted December 8, 2019 3 minutes ago, bluewave said: NAM ratios in NYC look like 6:1. But the colder surfaces can pick up a few inches if it snows hard enough. Probably will be 6-7 to start and finish at around 10 Link to comment Share on other sites More sharing options...
hudsonvalley21 Posted December 8, 2019 Share Posted December 8, 2019 Link to comment Share on other sites More sharing options...
purduewx80 Posted December 8, 2019 Share Posted December 8, 2019 Just now, White Gorilla said: Sorry if this is a stupid question, but could you please explain how higher velocity jet enhances precipitation? I understand that the high temperature contrast would lead to higher wind velocity in the jet stream, but how does that translate into enhanced lift? Not stupid at all, it's quite complicated. See https://www.weather.gov/source/zhu/ZHU_Training_Page/winds/JetStream_Stuff/300_200_chart.htm for some in-depth descriptions behind the fluid dynamics. The image below is a simple model of a straight jet, things get more complicated when the jet streak is curved cyclonically vs anti-cyclonically. In the right entrance region (or right-rear quad) of the jet streak (where we are in the 250mb map I posted), you have extreme divergence aloft. That rapidly evacuating air aloft has to be replaced, so you get strong ascent from below, lowering pressures, etc - all this creates areas of convergence/frontogenesis in the low and mid levels (specifically near 700mb in this instance). Basically the upper jet helps strengthen any lower level baroclinic zone, creates strong lift and enhances/creates banded precipitation. 2 2 Link to comment Share on other sites More sharing options...
NYCweatherNOW Posted December 8, 2019 Author Share Posted December 8, 2019 Gfs looks good. It has freezing temps and snowing hard Wednesday 12z. I assume the temps crash even harder than modeled with a system like this! Link to comment Share on other sites More sharing options...
Doorman Posted December 8, 2019 Share Posted December 8, 2019 ...Central Appalachians through New England... Day 3... A cold front will drop southeast through the region Tuesday afternoon, while a southern stream shortwave lags back across Texas. As this shortwave begins to lift northeast, forcing through height falls and mid-level divergence will lift atop the front producing anafrontal moisture. As the cold air continues to filter southeastward, the column will cool, and forcing may become intense through robust and steeply sloped 850-600mb frontogenesis overlapped with RRQ diffluence of an intensifying 170+kt upper jet streak. The combination of intense ascent and a cooling column will cause precipitation to changeover from rain to snow. The guidance still differs considerably in timing and location of precipitation, but confidence is increasing in at least light snow accumulations along a swath from central TN northeast into southern ME. WPC probabilities for 2" are above 10% only in the terrain of the central Appalachians and into the Catskills/Berkshires, but with such intense forcing it is possible the column will cool more rapidly, and light snow accumulations may be possible early Wednesday even into the I-95 corridor. https://origin.wpc.ncep.noaa.gov/discussions/hpcdiscussions.php?disc=qpfhsd Link to comment Share on other sites More sharing options...
White Gorilla Posted December 8, 2019 Share Posted December 8, 2019 13 minutes ago, purduewx80 said: Not stupid at all, it's quite complicated. See https://www.weather.gov/source/zhu/ZHU_Training_Page/winds/JetStream_Stuff/300_200_chart.htm for some in-depth descriptions behind the fluid dynamics. The image below is a simple model of a straight jet, things get more complicated when the jet streak is curved cyclonically vs anti-cyclonically. In the right entrance region (or right-rear quad) of the jet streak (where we are in the 250mb map I posted), you have extreme divergence aloft. That rapidly evacuating air aloft has to be replaced, so you get strong ascent from below, lowering pressures, etc - all this creates areas of convergence/frontogenesis in the low and mid levels (specifically near 700mb in this instance). Basically the upper jet helps strengthen any lower level baroclinic zone, creates strong lift and enhances/creates banded precipitation. Wow, thanks so much for the very detailed explanation and description. Fascinating stuff! I love learning about the details. Thanks too for the fluid dynamics link. Always wanted to be a meteorologist as a kid, but math wasn't my strongest subject and I got intimidated by the prospect of engineering level mathematics in grad school. I am, however, grateful I can enjoy it as a passionate hobby at least and learn some things from the pros like you. 4 Link to comment Share on other sites More sharing options...
Snowshack Posted December 8, 2019 Share Posted December 8, 2019 7 minutes ago, bluewave said: While I was just focusing on this decade, the warming around the solstice is a long term trend. But this is not a guarantee that it will happen every year. The coldest departures so far this month before the 15th also fit into the long term pattern. Notice how there is less warming during the first half of December than the second half. If this pattern continues into late December, then the 2nd half temperature departure may be milder than they first half. But the amount of departure will determine whether we finish the month with a positive or negative temperature departure. Is there another period in DJF that has warmed more rapidly? Link to comment Share on other sites More sharing options...
snowman19 Posted December 8, 2019 Share Posted December 8, 2019 This is far from a “crushing” NAM run: https://www.tropicaltidbits.com/analysis/models/?model=namconus®ion=neus&pkg=asnowd&runtime=2019120812&fh=84 1 Link to comment Share on other sites More sharing options...
NYCweatherNOW Posted December 8, 2019 Author Share Posted December 8, 2019 My thinking right now 1 2 Link to comment Share on other sites More sharing options...
SnoSki14 Posted December 8, 2019 Share Posted December 8, 2019 I think we'll be lucky to see an inch. 7 1 1 Link to comment Share on other sites More sharing options...
MJO812 Posted December 8, 2019 Share Posted December 8, 2019 9 minutes ago, snowman19 said: This is far from a “crushing” NAM run: https://www.tropicaltidbits.com/analysis/models/?model=namconus®ion=neus&pkg=asnowd&runtime=2019120812&fh=84 I haven't seen 1 meteorologist that uses the snow depth maps. Link to comment Share on other sites More sharing options...
MJO812 Posted December 8, 2019 Share Posted December 8, 2019 Just now, SnoSki14 said: I think we'll be lucky to see an inch. Reason ? This isnt your typical rain to snow. It's a wave along the front. Remember 2016? We got a few inches after the change over. 1 Link to comment Share on other sites More sharing options...
snowman19 Posted December 8, 2019 Share Posted December 8, 2019 15 minutes ago, Snow88 said: I haven't seen 1 meteorologist that uses the snow depth maps. Using 10:1 ratio snowmaps for Wednesday is ludicrous. The ratios are going to be lower than that, Bluewave explained in detail why before, to say they won’t be is wishcasting. Plus those maps count sleet as snow 1 3 Link to comment Share on other sites More sharing options...
NYCweatherNOW Posted December 8, 2019 Author Share Posted December 8, 2019 CMC is a miss basically Link to comment Share on other sites More sharing options...
EastonSN+ Posted December 8, 2019 Share Posted December 8, 2019 1 hour ago, frd said: Any recent changes on your opinion for later in the month ? Are you still ( and hopefully I am recalling correctly ) more hopeful about a more conducive pattern for Jan. into Feb? Wonder if we ever get an "ideal " pattern ? Very difficult to have both a favorable Pac and Atlantic at the same time. Don and Bluewave are better placed to discuss the long range. I am a mere hobbyist 2 Link to comment Share on other sites More sharing options...
SnowGoose69 Posted December 8, 2019 Share Posted December 8, 2019 UKMET at quick glance on poor maps seems like it could be significant but may be more for inland locations 2 Link to comment Share on other sites More sharing options...
MJO812 Posted December 8, 2019 Share Posted December 8, 2019 13 minutes ago, SnowGoose69 said: UKMET at quick glance on poor maps seems like it could be significant but may be more for inland locations Yep it doesnt hold back anything 1 Link to comment Share on other sites More sharing options...
EastonSN+ Posted December 8, 2019 Share Posted December 8, 2019 12 minutes ago, Snow88 said: Yep it doesnt hold back anything How much it show for area? Link to comment Share on other sites More sharing options...
MJO812 Posted December 8, 2019 Share Posted December 8, 2019 2 minutes ago, EastonSN+ said: How much it show for area? Few inches with more to the north. Heaviest is along the coast. These waves mostly favor the coast but temps are an issue. We have to work on that. Link to comment Share on other sites More sharing options...
EastonSN+ Posted December 8, 2019 Share Posted December 8, 2019 Just now, Snow88 said: Few inches with more to the north. Heaviest is along the coast. These waves mostly favor the coast but temps are an issue. We have to work on that. Thanks Link to comment Share on other sites More sharing options...
HeadInTheClouds Posted December 8, 2019 Share Posted December 8, 2019 58 minutes ago, snowman19 said: Using 10:1 ratio snowmaps for Wednesday is ludicrous. The ratios are going to be lower than that, Bluewave explained in detail why before, to say they won’t be is wishcasting. Plus those maps count sleet as snow Stop preaching. Those snow depth maps can be very inaccurate also. During last storm you posted those maps that showed Albany area getting ridiculously low amounts of additional snow. In reality they got a foot more than those maps were showing. You also said there was no way the setup for that storm was going to produce wintry precip. I wound up with 11 inches from your forecast rain storm. You need to be more specific on which area you are talking about or just STFU. 1 4 2 Link to comment Share on other sites More sharing options...
bluewave Posted December 8, 2019 Share Posted December 8, 2019 You know that people are hungry for snow after last winter. If a coating to 3 mainly on colder surfaces potential causes all this bickering, then better hope the KU snow machine cranks up before the winter is over. I can’t even imagine what this place would have been like from 96-97 to 01-02. Or even 79-80 to 91-92 for that matter. 6 1 Link to comment Share on other sites More sharing options...
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