BTRWx Posted January 11, 2017 Share Posted January 11, 2017 2 minutes ago, PaEasternWX said: If the nam went out longer it looks like nam'd There's a reason it doesn't. Link to comment Share on other sites More sharing options...
PaEasternWX Posted January 11, 2017 Share Posted January 11, 2017 1 minute ago, yoda said: Its only out to 60 that I see Look at that blob of moisture nam'd surface is below freezing if it went out farther Link to comment Share on other sites More sharing options...
yoda Posted January 11, 2017 Share Posted January 11, 2017 2 minutes ago, PaEasternWX said: Look at that blob of moisture nam'd surface is below freezing if it went out farther Meh... I foresee cold rain... especially since 850 line is already NW PA Link to comment Share on other sites More sharing options...
BTRWx Posted January 11, 2017 Share Posted January 11, 2017 1 minute ago, yoda said: Meh... I foresee cold rain... especially since 850 line is already NW PA Come on Yoda, use the better data! Link to comment Share on other sites More sharing options...
BTRWx Posted January 11, 2017 Share Posted January 11, 2017 Note the differences in 2m temperatures for 6z Saturday... eta: look along the spine of the Apps 18Z op NAM 18Z 4km NAM nest Link to comment Share on other sites More sharing options...
NorthArlington101 Posted January 11, 2017 Share Posted January 11, 2017 Toss that NAM run, we all know we'll get a good one eventually. Link to comment Share on other sites More sharing options...
WinterWxLuvr Posted January 11, 2017 Share Posted January 11, 2017 40 minutes ago, BristowWx said: NAM looks cold to me but I'm driving in and have a tiny phone So you feel a computer model weather forecast for 3 days in the future is a good reason to drive and try to read a phone screen at the same time? You sure you've thought that one through? Link to comment Share on other sites More sharing options...
BristowWx Posted January 11, 2017 Share Posted January 11, 2017 14 minutes ago, WinterWxLuvr said: So you feel a computer model weather forecast for 3 days in the future is a good reason to drive and try to read a phone screen at the same time? You sure you've thought that one through? I'm gonna go with no...but my addiction has rendered me powerless. I was at a train stop waiting for the train to pass. And fixing a drink of course. Link to comment Share on other sites More sharing options...
BTRWx Posted January 11, 2017 Share Posted January 11, 2017 1 minute ago, BristowWx said: I'm gonna go with no...but my addiction has rendered me powerless. I was at a train stop waiting for the train to pass. And fixing a drink of course. You have to be/act smart to be here. Link to comment Share on other sites More sharing options...
Bob Chill Posted January 11, 2017 Author Share Posted January 11, 2017 GFS backing off on the strength of HP. Now time to worry about the north trend. Link to comment Share on other sites More sharing options...
yoda Posted January 11, 2017 Share Posted January 11, 2017 Just now, Bob Chill said: GFS backing off on the strength of HP. Now time to worry about the north trend. 18z GFS at 66 looks decent enough Link to comment Share on other sites More sharing options...
Bob Chill Posted January 11, 2017 Author Share Posted January 11, 2017 3 minutes ago, yoda said: 18z GFS at 66 looks decent enough Looks good to me. If the column is too warm then it pretty much looks good everywhere. Link to comment Share on other sites More sharing options...
yoda Posted January 11, 2017 Share Posted January 11, 2017 2 minutes ago, Bob Chill said: Looks good to me. If the column is too warm then it pretty much looks good everywhere. Soundings should be snow at 66 and 69... 69 is probably more sleet than snow Link to comment Share on other sites More sharing options...
BTRWx Posted January 11, 2017 Share Posted January 11, 2017 8 minutes ago, yoda said: 18z GFS at 66 looks decent enough I'm with you Yoda. The trend is currently our friend. Even if she starts heading more north, the cad will save us! Link to comment Share on other sites More sharing options...
Bob Chill Posted January 11, 2017 Author Share Posted January 11, 2017 GFS is close to freezing through 12z Sun and if too warm then most everyone will be below freezing during that time. ZR could be a problem for some folks depending on how much precip moves through overnight Sat. Link to comment Share on other sites More sharing options...
Scraff Posted January 11, 2017 Share Posted January 11, 2017 Just checking back in. So we screwed? Or we looking at a potential WWA Saturday? I can't keep up. ;-) Link to comment Share on other sites More sharing options...
BristowWx Posted January 11, 2017 Share Posted January 11, 2017 12K NAM keeps below 32 longest for the most area coverage. I suppose it should be tossed at this range but nice to see anyway Link to comment Share on other sites More sharing options...
yoda Posted January 11, 2017 Share Posted January 11, 2017 Hey @Bob Chill check out e51 on the 12z EPS Link to comment Share on other sites More sharing options...
psuhoffman Posted January 11, 2017 Share Posted January 11, 2017 31 minutes ago, Bob Chill said: GFS backing off on the strength of HP. Now time to worry about the north trend. The area that gets anything more then conversational winter precip is only about 50-75 miles wide. Any trend can be a problem. Link to comment Share on other sites More sharing options...
BTRWx Posted January 11, 2017 Share Posted January 11, 2017 5 minutes ago, BristowWx said: 12K NAM keeps below 32 longest for the most area coverage. I suppose it should be tossed at this range but nice to see anyway Seeing the 4km run colder than 12km is a good sign. Link to comment Share on other sites More sharing options...
BTRWx Posted January 11, 2017 Share Posted January 11, 2017 1 minute ago, psuhoffman said: The area that gets anything more then conversational winter precip is only about 50-75 miles wide. Any trend can be a problem. Drizzle that freezes is the best! Link to comment Share on other sites More sharing options...
eurojosh Posted January 11, 2017 Share Posted January 11, 2017 GFS has the best look yet. Link to comment Share on other sites More sharing options...
WxMan1 Posted January 11, 2017 Share Posted January 11, 2017 1 hour ago, BTRWx said: Seeing the 4km run colder than 12km is a good sign. This should come as no surprise given the NAM's superiority over the other models in terms of vertical resolution. In these highly stratified CAD setups, like with the other freezing rain event last month, the lowest 100 feet can have a strong temperature inversion the global models just do not have a handle on. If the precip stops, and the sun can break through, great, you start mixing, and it's not a problem getting over 32. However if you've got a layer of snow/sleet/ice on the ground, and if it's still precipitating, I'm going to lean on the meso model that has the most vertical levels in the PBL (which I think is the NAM, but am not sure compared to the ARW, NMMB, or NSSL WRF). Just in the last event, I couldn't get over the fact that for over 2 hours the tops of some pretty tall trees in my neighborhood were swaying, yet at the surface we were dead calm with ice everywhere an stuck at 32F. The fact that the tops of the trees were moving was indicative of how close the mixing/warmer air was...so close and yet so far, as we didn't get above freezing until long after the FZRA quit (it took breaks in the cloud cover to do so). Link to comment Share on other sites More sharing options...
BristowWx Posted January 12, 2017 Share Posted January 12, 2017 39 minutes ago, WxMan1 said: This should come as no surprise given the NAM's superiority over the other models in terms of vertical resolution. In these highly stratified CAD setups, like with the other freezing rain event last month, the lowest 100 feet can have a strong temperature inversion the global models just do not have a handle on. If the precip stops, and the sun can break through, great, you start mixing, and it's not a problem getting over 32. However if you've got a layer of snow/sleet/ice on the ground, and if it's still precipitating, I'm going to lean on the meso model that has the most vertical levels in the PBL (which I think is the NAM, but am not sure compared to the ARW, NMMB, or NSSL WRF). Just in the last event, I couldn't get over the fact that for over 2 hours the tops of some pretty tall trees in my neighborhood were swaying, yet at the surface we were dead calm with ice everywhere an stuck at 32F. The fact that the tops of the trees were moving was indicative of how close the mixing/warmer air was...so close and yet so far, as we didn't get above freezing until long after the FZRA quit (it took breaks in the cloud cover to do so). Interesting. So do the mesoscale models take this into account in advance? I mean in their numerical solution, is the fact of accumulated frozen precip weighted into the solutions they put out every six hours and then refined as the event gets closer? Link to comment Share on other sites More sharing options...
WxMan1 Posted January 12, 2017 Share Posted January 12, 2017 44 minutes ago, BristowWx said: Interesting. So do the mesoscale models take this into account in advance? I mean in their numerical solution, is the fact of accumulated frozen precip weighted into the solutions they put out every six hours and then refined as the event gets closer? I believe so. Sometimes, the CAD can be overdone, as in the case last month over the NC Piedmont during the same freezing rain event we had. The NAM 3km took too long to scour out the surface cold air in that case. The likely culprit? They did not get the precip the NAM was progging, thus the breaks in the overcast and the surface mixing arrived sooner. As you know, precip helps to cool the surface layer through the latent effects of evaporation and (when applicable) melting. As you alluded to, I think if the model senses snow/sleet/ice cover, then there's probably an added diabatic (cooling) component fed back into the calculation of surface temp. And in the absence of warm advection (which is pretty hard to get stuck in a CAD wedge with little if any surface wind), any bit of latent cooling from evaporation and/or melting can most certainly keep surface temps down. It's all about the precip though. It's much easier to hold the temps in check while maintaining precipitation, even if only drizzle. Link to comment Share on other sites More sharing options...
BristowWx Posted January 12, 2017 Share Posted January 12, 2017 12 minutes ago, WxMan1 said: I believe so. Sometimes, the CAD can be overdone, as in the case last month over the NC Piedmont during the same freezing rain event we had. The NAM 3km took too long to scour out the surface cold air in that case. The likely culprit? They did not get the precip the NAM was progging, thus the breaks in the overcast and the surface mixing arrived sooner. As you know, precip helps to cool the surface layer through the latent effects of evaporation and (when applicable) melting. As you alluded to, I think if the model senses snow/sleet/ice cover, then there's probably an added diabatic (cooling) component fed back into the calculation of surface temp. And in the absence of warm advection (which is pretty hard to get stuck in a CAD wedge with little if any surface wind), any bit of latent cooling from evaporation and/or melting can most certainly keep surface temps down. It's all about the precip though. It's much easier to hold the temps in check while maintaining precipitation, even if only drizzle. Thank you. I admire the work you guys do. you are living the dream...weather every day for a job. Must be awesome. Link to comment Share on other sites More sharing options...
BTRWx Posted January 12, 2017 Share Posted January 12, 2017 10 minutes ago, BristowWx said: Thank you. I admire the work you guys do. you are living the dream...weather every day for a job. Must be awesome. Double thanks! He just blew my mind. Link to comment Share on other sites More sharing options...
BristowWx Posted January 12, 2017 Share Posted January 12, 2017 2 minutes ago, BTRWx said: Double thanks! He just blew my mind. I know right. Getting an answer to a weather question from someone a senior forecaster at NCEP is like having Mick Jagger explain the finer points of rock and roll. Link to comment Share on other sites More sharing options...
BTRWx Posted January 12, 2017 Share Posted January 12, 2017 This could be looks bad. Link to comment Share on other sites More sharing options...
WxMan1 Posted January 12, 2017 Share Posted January 12, 2017 8 minutes ago, BristowWx said: I know right. Getting an answer to a weather question from someone a senior forecaster at NCEP is like having Mick Jagger explain the finer points of rock and roll. 14 minutes ago, BTRWx said: Double thanks! He just blew my mind. Thanks guys!! Like you, I have a passion for winter weather! Link to comment Share on other sites More sharing options...
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