TheTrials Posted December 5, 2011 Share Posted December 5, 2011 1004mb surface low just off of Ocean City Maryland at 66 hrs. Precip for everybody but it looks like rain. Best dynamics still south of us so far. 40 F line running just east of NYC. it's not cold enough till its over, which is pretty much should be expected in this setup. Link to comment Share on other sites More sharing options...
earthlight Posted December 5, 2011 Author Share Posted December 5, 2011 Link to comment Share on other sites More sharing options...
NaoPos Posted December 5, 2011 Share Posted December 5, 2011 it's not cold enough till its over, which is pretty much should be expected in this setup. Adam is saying 2-4" in the phl thread from richmond to portland. Link to comment Share on other sites More sharing options...
TheTrials Posted December 5, 2011 Share Posted December 5, 2011 Adam is saying 2-4" in the phl thread from richmond to portland. I dont have soundings, but i would imagine based on how warm things are to start that a lot of what falls along the coast would be wet. Further inland and high in elevation different. Soundings will come out later. Link to comment Share on other sites More sharing options...
TheTrials Posted December 5, 2011 Share Posted December 5, 2011 John, look at how warm it is to start, its not a great profile to aritifically, cool, so the 850 and 540 lines when the storm is over could really be deceiving here. Someone will have the text output soon enough. Link to comment Share on other sites More sharing options...
MJO812 Posted December 5, 2011 Share Posted December 5, 2011 John, look at how warm it is to start, its not a great profile to aritifically, cool, so the 850 and 540 lines when the storm is over could really be deceiving here. Someone will have the text output soon enough. I thought the Euro has a warm bias. A lot of people have said this. Link to comment Share on other sites More sharing options...
jm1220 Posted December 5, 2011 Share Posted December 5, 2011 I dont have soundings, but i would imagine based on how warm things are to start that a lot of what falls along the coast would be wet. Further inland and high in elevation different. Soundings will come out later. I think too much is made of how the coast can't snow and only inland can in marginal setups like this. I think that dynamics will play a role, but if the coast can sustain winds from the N or NNE behind the front, they can change over quicker than many expect. Obviously it snowed over most of LI enough to stick before Halloween. I remember a lot of people saying the same on 12/5/03, when the non-dynamic WAA precip was all snow all across Long Island. That's of course if this vort/low can take a favorable track. Again, the pattern dictates that we about need perfect luck for that to happen. Link to comment Share on other sites More sharing options...
TheTrials Posted December 5, 2011 Share Posted December 5, 2011 I thought the Euro has a warm bias. A lot of people have said this. it can be a little warm with surface temps, but with such a bad antecedent airmass, i don't think its off here. Soundings will be the key. We are only seeing 6 hour increments and its too warm to snow when already almost .25 has fallen in KNYC 6 hours later, its over, and then the profiles look good for wet snow, but in between, is a mysters till the soundings come out. Link to comment Share on other sites More sharing options...
uofmiami Posted December 5, 2011 Share Posted December 5, 2011 Hi guys! Just wanted to stop in and see how things were going! Real bad, we have a +AO & +NAO, we are screwed! Link to comment Share on other sites More sharing options...
TheTrials Posted December 5, 2011 Share Posted December 5, 2011 I think too much is made of how the coast can't snow and only inland can in marginal setups like this. I think that dynamics will play a role, but if the coast can sustain winds from the N or NNE behind the front, they can change over quicker than many expect. Obviously it snowed over most of LI enough to stick before Halloween. I remember a lot of people saying the same on 12/5/03, when the non-dynamic WAA precip was all snow all across Long Island. That's of course if this vort/low can take a favorable track. Again, the pattern dictates that we about need perfect luck for that to happen. this isn't a bombing LP with H5 cutoff etc. Its a very FM system with limited room to cool. l don't see the dynamics here necessary for the coast to see anything substantial accumulate. Link to comment Share on other sites More sharing options...
tmagan Posted December 5, 2011 Share Posted December 5, 2011 KISP NAM BUFKIT sounding December 8th 11Z. Link to comment Share on other sites More sharing options...
atownwxwatcher Posted December 5, 2011 Share Posted December 5, 2011 Just thought i would add 66 hours in here! Link to comment Share on other sites More sharing options...
snywx Posted December 5, 2011 Share Posted December 5, 2011 Just thought i would add 66 hours in here! But what a minute... Its impossible!! It cant happen Lookin good for areas just inland with some elevation.. Maybe 2-4" Link to comment Share on other sites More sharing options...
jm1220 Posted December 5, 2011 Share Posted December 5, 2011 this isn't a bombing LP with H5 cutoff etc. Its a very FM system with limited room to cool. l don't see the dynamics here necessary for the coast to see anything substantial accumulate. On 12/5/03, we had all snow even to the beaches, well before the low started to bomb. It was all warm advection snow then. It's not a ridiculously early time of the year to see snow at the coast without a bombing low, and the air behind the front at least seems marginally cold. Not to say it's all snow or anything there, but Euro at least looks to me like a period of snow for a while as the storm departs. Link to comment Share on other sites More sharing options...
TheTrials Posted December 5, 2011 Share Posted December 5, 2011 On 12/5/03, we had all snow even to the beaches, well before the low started to bomb. It was all warm advection snow then. It's not a ridiculously early time of the year to see snow at the coast without a bombing low, and the air behind the front at least seems marginally cold. Not to say it's all snow or anything there, but Euro at least looks to me like a period of snow for a while as the storm departs. woa, it was cold on 12/5/03, ice cold with a strong hp to the north. Not even close to this setup. Here is the setup. Link to comment Share on other sites More sharing options...
TheTrials Posted December 5, 2011 Share Posted December 5, 2011 But what a minute... Its impossible!! It cant happen Lookin good for areas just inland with some elevation.. Maybe 2-4" no one said that for Middletown NY at 800 feet elevation at the foot of the catskills. Link to comment Share on other sites More sharing options...
ag3 Posted December 5, 2011 Share Posted December 5, 2011 Euro has snow, even to NYC. 1"-3" in this pattern is great. Link to comment Share on other sites More sharing options...
earthlight Posted December 5, 2011 Author Share Posted December 5, 2011 Wunderground maps are 2-4" with locally higher amounts everywhere. Link to comment Share on other sites More sharing options...
jm1220 Posted December 5, 2011 Share Posted December 5, 2011 woa, it was cold on 12/5/03, ice cold with a strong hp to the north. Not even close to this setup. Here is the setup. Most predictions that day had maybe 1-2" of slop to rain for Nassau County, before the main snow hit the next day. By the night of 12/5, we had 8" on the ground and not one drop of rain or a sleet pellet. We had another 5-6" the next day for an event total of around 14". I think we were maybe 35F or so that morning, and then we crashed down to 28-29 and stayed there. Link to comment Share on other sites More sharing options...
MJO812 Posted December 5, 2011 Share Posted December 5, 2011 Even D.C sees accumulating snow on the Euro. Impressive. Link to comment Share on other sites More sharing options...
WeatherFox Posted December 5, 2011 Share Posted December 5, 2011 Wunderground maps are 2-4" with locally higher amounts everywhere. But you don't believe it though.. Link to comment Share on other sites More sharing options...
ag3 Posted December 5, 2011 Share Posted December 5, 2011 Euro will get wetter every run. It has over 1" of precip in Richmond area. Expect to see that spread up to our area. Link to comment Share on other sites More sharing options...
jm1220 Posted December 5, 2011 Share Posted December 5, 2011 Euro will get wetter every run. It has over 1" of precip in Richmond area. Expect to see that spread up to our area. I'm actually surprised it's this wet given how weak a vort this is overall. Not a tremendous amount of forcing or dynamics. Link to comment Share on other sites More sharing options...
eduggs Posted December 5, 2011 Share Posted December 5, 2011 The shortwave is de-amplifying rapidly as it traverses east thanks to the influence of the height field to the north. That is actually "saving us" in this situation (aka giving us more than a 0% chance), so although it is a southwest flow event it is not your typical one. The shortwave is weakening because the longwave pattern is evolving into a configuration that doesn't favor strengthening, i.e., it's not on the downstream side of the trof base. But moreso, it's deamplifying because the strongest winds aloft are downstream, which is kind of like pulling a curved rope straight. I'm not a physicist, but I think this analogy is valid. Weakening waves can be bores because they rarely become real or modeled blizzards. They rarely produce prolonged or excessive QPF, and they lack dynamics. But this is also why they produce some of the best surprises - because they are downplayed. In our case we have a very nice looking wave at 48hours or so that dissipates fairly rapidly. But a pretty decent surface front sags south of our latitude before some good southerly flow sets at all levels producing some WAA over top of the shallow cold. Early on, that could produce some short lived moderate or heavy precipitation, especially just to the southwest. I think surface temperatures look marginally cold for snow, esp. just west of I-95. I don't think this is quite so hopeless as a thread-the-needle scenario. If the airmass is supportive (temps and dews on Wed in the upstate will give a hint) and a distinct shortwave and area of PVA survives into the Mid-atlantic, I think someone in the tri-state has a low to moderate probability of at least 1" of snow. Link to comment Share on other sites More sharing options...
phils1 Posted December 5, 2011 Share Posted December 5, 2011 Detailed video discussion on the latest 12Z GFS and 12Z NAM model runs at http://spam.com/category/phl/ with a focus on the much more similar handling by the models of the upper level system associated with this potential storm. Both models suggest snow late Wednesday night and early Thursday in the Mid-Atlantic region, including the I-95 corridor, with some accumulations possible. Link to comment Share on other sites More sharing options...
earthlight Posted December 5, 2011 Author Share Posted December 5, 2011 But you don't believe it though.. The entire thing is still questionable to me. Yesterday I said that I thought it would be extremely, extremely hard to get snow into the city or surrounding areas in this pattern..and I obviously meant that lol. It will take the perfect timing and perfect track to get that to happen. Link to comment Share on other sites More sharing options...
Sundog Posted December 5, 2011 Share Posted December 5, 2011 woa, it was cold on 12/5/03, ice cold with a strong hp to the north. Not even close to this setup. The temps were near 40 that night in the city before that snow began. Plus the rain/snow line was much farther south in 12/03. All we need it to be is just south of our area. Link to comment Share on other sites More sharing options...
eduggs Posted December 5, 2011 Share Posted December 5, 2011 1) That is previous precip and current 850 temps, means very little 2) Surface could be torching, no way to know Only one member shows a semi-torch at the surface. The rest are marginally supportive of snow, at least away from the immediate coast (and especially after 09z Thursday morning). Interestingly there are a few members that delay the deamplification of the shortwave and really blow up the storm off the SNE coast. That's noteworthy as guidance almost universally weakens the mid-level support fairly rapidly. There are more members showing a good hit than not this run. Link to comment Share on other sites More sharing options...
eduggs Posted December 5, 2011 Share Posted December 5, 2011 John, look at how warm it is to start, its not a great profile to aritifically, cool, so the 850 and 540 lines when the storm is over could really be deceiving here. Someone will have the text output soon enough. It's not artificial cooling. It's synoptic cooling. CAA. Winds are out of the west and northwest south of around 700mb. Whether this boundary to a supportive airmass sags far enough south in the first place is a question I still have. If the shortwave (which is really superimposed on the longwave before 48hrs or so) is actually a bit stronger than currently modeled, the surface low could make an early run towards the Ohio Valley. The resulting southerly flow would initially taint the boundary layer airmass (something like the UKMET depiction), but it should definitely cool if and when a surface low forms or tracks southeast of the metro. Link to comment Share on other sites More sharing options...
TheTrials Posted December 5, 2011 Share Posted December 5, 2011 It's not artificial cooling. It's synoptic cooling. CAA. Winds are out of the west and northwest south of around 700mb. Whether this boundary to a supportive airmass sags far enough south in the first place is a question I still have. If the shortwave (which is really superimposed on the longwave before 48hrs or so) is actually a bit stronger than currently modeled, the surface low could make an early run towards the Ohio Valley. The resulting southerly flow would initially taint the boundary layer airmass (something like the UKMET depiction), but it should definitely cool if and when a surface low forms or tracks southeast of the metro. The synoptic cooling doesn't kick in until after the precip is well underway and almost over, especially with only a small 6 hour window here. Link to comment Share on other sites More sharing options...
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