usedtobe Posted February 17, 2012 Share Posted February 17, 2012 Yeah we have been. I had some hope we could maybe get at least grazed, yesterday..but I don't think it's going to happen. I swear 7/10 times this would have probably come north enough to graze us, but the confluence this time around is killing us, even without a strong block. For use I think the most interesting thing has been the vort dropping out of the north that produces the confluence and delivers and actual cold shot taking a marginal airmass on the NAm and making it a cold one. Of course the dynamics and strong lifting are also helping but the cooling start before the precip gets here. The 18Z gfs did the same thing albeit with less precip and a little less cold. Link to comment Share on other sites More sharing options...
winterymix Posted February 17, 2012 Share Posted February 17, 2012 For anyone with the Kocin book nearby, none of the near misses seem much like the NAM depiction. None of the near misses depict good snow to the PA line with a cut-off in southern NJ. This should be far short of a KU system but here are some old analogs from the book: 20-21 Feb 1929 18-20 Feb 1979 25-27 Jan 1987 22-24 Feb 1987 Link to comment Share on other sites More sharing options...
Midlo Snow Maker Posted February 17, 2012 Share Posted February 17, 2012 48 hr RGEM looks a bit like the NAM at 48 hrs to this weenie http://www.weatherof...ast/520_100.gif mitch do us a favor. you post so many links can you just insert them by clicking on this box and pasting the link in--- help a weenie out Link to comment Share on other sites More sharing options...
CoastalWx Posted February 17, 2012 Share Posted February 17, 2012 For use I think the most interesting thing has been the vort dropping out of the north that produces the confluence and delivers and actual cold shot taking a marginal airmass on the NAm and making it a cold one. Of course the dynamics and strong lifting are also helping but the cooling start before the precip gets here. The 18Z gfs did the same thing albeit with less precip and a little less cold. That's also a nice high presentation that you have...maybe even classic looking for you guys? Anyways, it's kind of funny because Saturday will not feel like snow, with those temps. But, the mercury falls Saturday Night, just in time for the moisture to come in. At least that's how it looks for now. You guys still could see movement to the north or south a bit. Link to comment Share on other sites More sharing options...
ACFD FIREMAN Posted February 17, 2012 Share Posted February 17, 2012 What an amazingly odd looking "decent" snow producer for us. Still, it looks great. Link to comment Share on other sites More sharing options...
mitchnick Posted February 17, 2012 Share Posted February 17, 2012 mitch do us a favor. you post so many links can you just insert them by clicking on this box and pasting the link in--- help a weenie out OK, I do it sometimes but don't do it for fear of the old days when there were seemingly hundreds of them in a thread and slowed the board Link to comment Share on other sites More sharing options...
baroclinic_instability Posted February 17, 2012 Share Posted February 17, 2012 The 0Z NAM verbatim is one of the most impressive displays of frontogenetic processes you will ever see in a non oceanic bomb complete with perfect horizontal deformation frontogenesis, likely some negative EPV/convective instability, and a nearly vertically co-located mid level front/upper level divergent jet streak. It would be the perfect setup, and a rare example of a non Noreaster event for the MA with heavy snow potential. Link to comment Share on other sites More sharing options...
baroclinic_instability Posted February 17, 2012 Share Posted February 17, 2012 That's also a nice high presentation that you have...maybe even classic looking for you guys? Anyways, it's kind of funny because Saturday will not feel like snow, with those temps. But, the mercury falls Saturday Night, just in time for the moisture to come in. At least that's how it looks for now. You guys still could see movement to the north or south a bit. I was thinking it was a bit "non-classical". It is a somewhat odd storm to me because there is little to no coastal influence. Only classic part to me is the lee-side development (at least IMO). Link to comment Share on other sites More sharing options...
mitchnick Posted February 17, 2012 Share Posted February 17, 2012 The 0Z NAM verbatim is one of the most impressive displays of frontogenetic processes you will ever see in a non oceanic bomb complete with perfect horizontal deformation frontogenesis, likely some negative EPV/convective instability, and a nearly vertically co-located mid level front/upper level divergent jet streak. It would be the perfect setup, and a rare example of a non Noreaster event for the MA with heavy snow potential. I recall that PDII had an impressive east-west band before the SLP got going that was very slow to progress to the north with heavy snow (BWI had T-snow) any similarities Link to comment Share on other sites More sharing options...
CoastalWx Posted February 17, 2012 Share Posted February 17, 2012 The 0Z NAM verbatim is one of the most impressive displays of frontogenetic processes you will ever see in a non oceanic bomb complete with perfect horizontal deformation frontogenesis, likely some negative EPV/convective instability, and a nearly vertically co-located mid level front/upper level divergent jet streak. It would be the perfect setup, and a rare example of a non Noreaster event for the MA with heavy snow potential. Yeah I thought it looked great. For those who just want to see a simplified version of this, just look at the H7 winds at 18z Sunday. Notice how 50kt south winds are just south of DC with nearly calm winds just north of the center. That means one thing..convergence and rising motion. Also note weak north winds across PA. Big time thermal packing in the mid levels, if this were to happen. It's the NAM, but I think it has the idea of a very strong band on the nrn periphery of this. We always see this when there is good confluence in the northeast. Link to comment Share on other sites More sharing options...
PhineasC Posted February 17, 2012 Share Posted February 17, 2012 Yeah I thought it looked great. For those who just want to see a simplified version of this, just look at the H7 winds at 18z Sunday. Notice how 50kt south winds are just south of DC with nearly calm winds just north of the center. That means one thing..convergence and rising motion. Also note weak north winds across PA. Big time thermal packing in the mid levels, if this were to happen. It's the NAM, but I think it has the idea of a very strong band on the nrn periphery of this. We always see this when there is good confluence in the northeast. Thank you. The first post was clearly made by a brilliant met, but I was too dumb to understand. Let him write the textbook and then you teach it. Link to comment Share on other sites More sharing options...
usedtobe Posted February 17, 2012 Share Posted February 17, 2012 I was thinking it was a bit "non-classical". It is a somewhat odd storm to me because there is little to no coastal influence. Only classic part to me is the lee-side development (at least IMO). It is but in some ways has morphed into one that has some similarites. We have the upper low near nova scotia to help with the confluence and a vort track that is pretty classic as is the 850 low track. It's odd to get them in a la nina year with a positive AO but I guess stats are only stats. Link to comment Share on other sites More sharing options...
gymengineer Posted February 17, 2012 Share Posted February 17, 2012 For anyone with the Kocin book nearby, none of the near misses seem much like the NAM depiction. None of the near misses depict good snow to the PA line with a cut-off in southern NJ. This should be far short of a KU system but here are some old analogs from the book: 20-21 Feb 1929 18-20 Feb 1979 25-27 Jan 1987 22-24 Feb 1987 1/30/10: Link to comment Share on other sites More sharing options...
CoastalWx Posted February 17, 2012 Share Posted February 17, 2012 I was thinking it was a bit "non-classical". It is a somewhat odd storm to me because there is little to no coastal influence. Only classic part to me is the lee-side development (at least IMO). I thought for MA snows..the way the confluence is to the northeast..that the high was a little more classical looking. Even the Feb 6 2010 deal had the high to the nw. But, I'll leave that to Wes..that is his expertise. Link to comment Share on other sites More sharing options...
midatlanticweather Posted February 17, 2012 Share Posted February 17, 2012 It is times like this, when the mets get talking, that I just am amazed at what they teach! Thanks mets! Link to comment Share on other sites More sharing options...
usedtobe Posted February 17, 2012 Share Posted February 17, 2012 Thank you. The first post was clearly made by a brilliant met, but I was too dumb to understand. Let him write the textbook and then you teach it. Phin, Another thing to look for is at the 850 low and the temp lines around it. When they are really getting squeezed together with time and you also have convergence across the region, you usually will have some kind of deformation zone and banding especially if the winds a blowing across the temp lines in a direction that should be bringing some warm air northward or westward and instead the temp lines at 850 are shifting south and east. Then you usually have frontogenesis which when its strong enough can lead to epv (slantwise convection). The latter is just another type of instability that can lead to enhanced upward motion and precip rates. Link to comment Share on other sites More sharing options...
gymengineer Posted February 17, 2012 Share Posted February 17, 2012 And I know this site lost its luster once we moved past the 09/10 winter (where it produced some Wes-like accurate forecasts well in advance), but click the SE and NE squares at hour-72 and explore a bit: http://www.eas.slu.e...COLD/analog.php These are analogs run off of the 12Z GFS Link to comment Share on other sites More sharing options...
BlizzardNole Posted February 17, 2012 Share Posted February 17, 2012 ... it's kind of funny because Saturday will not feel like snow, with those temps. But, the mercury falls Saturday Night, just in time for the moisture to come in. At least that's how it looks for now... I remember a storm in early February 1997 where it was in the 50s the day before and I was not buying into a storm happening. I remember chuckling when I heard winter storm warning on the radio that afternoon, but it did snow about 6" in central MD the next day - very wet snow. I don't know what happened in the cities, or what kind of set-up it was. Ring a bell for anyone? Link to comment Share on other sites More sharing options...
PhineasC Posted February 17, 2012 Share Posted February 17, 2012 Phin, Another thing to look for is at the 850 low and the temp lines around it. When they are really getting squeezed together with time and you also have convergence across the region, you usually will have some kind of deformation zone and banding especially if the winds a blowing across the temp lines in a direction that should be bringing some warm air northward or westward and instead the temp lines at 850 are shifting south and east. Then you usually have frontogenesis which when its strong enough can lead to epv (slantwise convection). The latter is just another type of instability that can lead to enhanced upward motion and precip rates. Ha, I have distilled this all down into my theory of the "Leesburg Heavy Snow Band." My theory says that Leesburg gets fringed in every big storm coming up from the south but a mega-band always sets up over them anyway and they do great. Link to comment Share on other sites More sharing options...
HM Posted February 17, 2012 Share Posted February 17, 2012 The 60hr NAM at 850mb has a classic deformation zone across the Mid Atlantic. This is like it came out of a book or something (although I know it should be plotted on potential temperature). Link to comment Share on other sites More sharing options...
HoarfrostHubb Posted February 17, 2012 Share Posted February 17, 2012 Thank you. The first post was clearly made by a brilliant met, but I was too dumb to understand. Let him write the textbook and then you teach it. I've told him several times he could teach this. He's damned good at that Link to comment Share on other sites More sharing options...
Deck Pic Posted February 17, 2012 Share Posted February 17, 2012 I remember a storm in early February 1997 where it was in the 50s the day before and I was not buying into a storm happening. I remember chuckling when I heard winter storm warning on the radio that afternoon, but it did snow about 6" in central MD the next day - very wet snow. I don't know what happened in the cities, or what kind of set-up it was. Ring a bell for anyone? yes...2/8/97....nice 4-7" storm.....didn't stick that well though Link to comment Share on other sites More sharing options...
gymengineer Posted February 17, 2012 Share Posted February 17, 2012 I remember a storm in early February 1997 where it was in the 50s the day before and I was not buying into a storm happening. I remember chuckling when I heard winter storm warning on the radio that afternoon, but it did snow about 6" in central MD the next day - very wet snow. I don't know what happened in the cities, or what kind of set-up it was. Ring a bell for anyone? Matt already answered you... although the 50's were 3 days before the storm, not the day before. 2/7 highs: 43 DCA, 41 IAD, 42 BWI Link to comment Share on other sites More sharing options...
snownerd Posted February 17, 2012 Share Posted February 17, 2012 I took the NE and SE sim radars at hour 60 from http://www.meteo.psu...ewallhires.html and hooked them together, looks nice: Link to comment Share on other sites More sharing options...
MD Snow Posted February 17, 2012 Share Posted February 17, 2012 Northern stream looks a little stronger this go around and things looks slightly suppressed so far. Link to comment Share on other sites More sharing options...
PhineasC Posted February 17, 2012 Share Posted February 17, 2012 The GFS appears to be doing something similar to the NAM. The first piece of 500 energy is racing ahead and another piece is hanging back and dropping south. Link to comment Share on other sites More sharing options...
snowdude Posted February 17, 2012 Share Posted February 17, 2012 ok, enough old snowstorm memories. GFS is out to 42. Link to comment Share on other sites More sharing options...
yoda Posted February 17, 2012 Share Posted February 17, 2012 00z GFS and 18z GFS match SLP placement at 8 PM SAT (00z SUN, which is at 48 hrs on 00z NAM fyi)... 00z has a bit more QPF in MS/AL Link to comment Share on other sites More sharing options...
baroclinic_instability Posted February 17, 2012 Share Posted February 17, 2012 0z GFS is definitely not going to be a NAM run. It has more frontal DMC early which inhibits advection across the WCB early on. It looks flatter aloft too. Link to comment Share on other sites More sharing options...
PhineasC Posted February 17, 2012 Share Posted February 17, 2012 0z GFS is definitely not going to be a NAM run. It has more frontal DMC early which inhibits advection across the WCB early on. It looks flatter aloft too. That doesn't sound good. Link to comment Share on other sites More sharing options...
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