Deck Pic Posted February 14, 2016 Share Posted February 14, 2016 The intensity of the rain matters a lot. Moderate to heavy rain is not going to acrete significantly at or near freezing. Not to mention, water has a very high specific heat, and a much greater thermal conductivity than air. Therefore, rain will quickly bring the surface temp to the temperature of the rain. I don't think the cold ground matters for very long. I think the evolution here is really important. Not saying the 4kNAM is right, but there is a pretty big lull in the western burbs before the big warm push comes, and even then the model keeps the western burbs at 32. This is kind of a 2-part event and we have to score some precip in part 1 ETA - this is hour 51 Link to comment Share on other sites More sharing options...
EastCoast NPZ Posted February 14, 2016 Share Posted February 14, 2016 I think the evolution here is really important. Not saying the 4kNAM is right, but there is a pretty big lull in the western burbs before the big warm push comes, and even then the model keeps the western burbs at 32. This is kind of a 2-part event and we have to score some precip in part 1 Screen Shot 2016-02-13 at 10.04.10 PM.png That scenario is our worst nightmare out here. Link to comment Share on other sites More sharing options...
Bob Chill Posted February 14, 2016 Share Posted February 14, 2016 Bob, I respect you, but if you look at the pages back me and ers-wxman were both doing detailed pbp of the NAM... I made one sarcastic posts that half of the board seemed to get... and suddenly got attacked while at least two Winchester guy sarcastically mourned about their 0.1" of precipitation. And also, RGEM looks marginally warmer at the surface than the NAM... would probably mean less ice, especially for the non-favored areas. In the hours between runs banter doesn't matter much. But right in the middle runs posting something that causes a slew of responses is a derailment and not why we're here. Winchester guys bumming out a out light precip and posting about it won't derail anything. There's a difference. On topic- the rgem makes more sense than the Nam. A little warmer at the surface and not as prolific with the front end stuff. Link to comment Share on other sites More sharing options...
kurtstack Posted February 14, 2016 Share Posted February 14, 2016 the jet stream tends to tell ya where the high pressure will go. look at 250mb winds and that will explain it. Sent from my iPhone using Tapatalk Link to comment Share on other sites More sharing options...
Deck Pic Posted February 14, 2016 Share Posted February 14, 2016 That scenario is our worst nightmare out here. you've already gotten 0.4" QPF by this point with temps in the teens and 20s Link to comment Share on other sites More sharing options...
WinterWxLuvr Posted February 14, 2016 Share Posted February 14, 2016 you've already gotten 0.4" QPF by this point with temps in the teens and 20s Yeah, the 4K is a better event for the most part because its so much colder. Link to comment Share on other sites More sharing options...
WinterWxLuvr Posted February 14, 2016 Share Posted February 14, 2016 Somebody post the link to the color rgem maps I see posted here. The ones with precip type. Link to comment Share on other sites More sharing options...
Bob Chill Posted February 14, 2016 Share Posted February 14, 2016 Yeah, the 4K is a better event for the most part because its so much colder. One thing I question about the nam twins is punching precip into the hp so early. That's a tall order with a 1035+ not too far away. RGEM makes more sense in my brain even though it's not as kind in the snow dept. I hope my logic is flawed. Link to comment Share on other sites More sharing options...
cae Posted February 14, 2016 Share Posted February 14, 2016 Somebody post the link to the color rgem maps I see posted here. The ones with precip type. Do you mean this one? http://collaboration.cmc.ec.gc.ca/cmc/cmdn/pcpn_type/pcpn_type_gem_reg.html It's usually one of the first sites to show the RGEM. Link to comment Share on other sites More sharing options...
hazwoper Posted February 14, 2016 Share Posted February 14, 2016 I think the evolution here is really important. Not saying the 4kNAM is right, but there is a pretty big lull in the western burbs before the big warm push comes, and even then the model keeps the western burbs at 32. This is kind of a 2-part event and we have to score some precip in part 1 ETA - this is hour 51 Screen Shot 2016-02-13 at 10.04.10 PM.png The heavy precip after that lull would easily push surface temps above 32 Link to comment Share on other sites More sharing options...
psuhoffman Posted February 14, 2016 Share Posted February 14, 2016 You should be a professional meteorologist for the NWS who only forecasts bust scenarios. since we fail 90% of the time, finding the way we fail seems to be the best way to forecast. When I start having trouble finding a way to fail that's when I know we get crushed. I knew 72 hours out dc to balt was getting obliterated by snowzilla and by 48 hours when the euro started to cave knew up here was too. Unfortunately fail is usually the better way to go. Sometimes I'm also just throwing out what to be wary of. Someone has to be the pessimist. Link to comment Share on other sites More sharing options...
Deck Pic Posted February 14, 2016 Share Posted February 14, 2016 The heavy precip after that lull would easily push surface temps above 32 I've never asserted otherwise...though I haven't followed this event for the far northern Philly suburbs, so not sure what will happen there Link to comment Share on other sites More sharing options...
Deck Pic Posted February 14, 2016 Share Posted February 14, 2016 One other thing to mention that I was going to post before the board went down - I'd definitely want to be in the usual elevated spots for this one. Hopefully we can at least get some light snow during the day on Monday since it will stick...It would be ashame not to take some advantage of the air mass.....I think it also worth reminding everyone that the ice event last winter was really impressive, even here. It is hard to get some epic ice event, but minor-moderate ice events can happen, even in DC (not saying it will this time). Link to comment Share on other sites More sharing options...
cae Posted February 14, 2016 Share Posted February 14, 2016 One other thing to mention that I was going to post before the board went down - I'd definitely want to be in the usual elevated spots for this one. Hopefully we can at least get some light snow during the day on Monday since it will stick...It would be ashame not to take some advantage of the air mass.....I think it also worth reminding everyone that the ice event last winter was really impressive, even here. It is hard to get some epic ice event, but minor-moderate ice events can happen, even in DC (not saying it will this time). In a CAD event, are lower elevations more likely to see ice? Link to comment Share on other sites More sharing options...
WinterWxLuvr Posted February 14, 2016 Share Posted February 14, 2016 Do you mean this one? http://collaboration.cmc.ec.gc.ca/cmc/cmdn/pcpn_type/pcpn_type_gem_reg.html It's usually one of the first sites to show the RGEM. That's the one. Thank you. Link to comment Share on other sites More sharing options...
WinterWxLuvr Posted February 14, 2016 Share Posted February 14, 2016 One thing I question about the nam twins is punching precip into the hp so early. That's a tall order with a 1035+ not too far away. RGEM makes more sense in my brain even though it's not as kind in the snow dept. I hope my logic is flawed. That evolution works well here according to that depiction but it would be tough waiting for it. Link to comment Share on other sites More sharing options...
BTRWx Posted February 14, 2016 Share Posted February 14, 2016 In a CAD event, are lower elevations more likely to see ice? Sometimes that can happen, but I think it's more a case by case basis. Of course western areas and higher elevations are typically favored, but not always. For this event they are. Link to comment Share on other sites More sharing options...
ers-wxman1 Posted February 14, 2016 Share Posted February 14, 2016 In a CAD event, are lower elevations more likely to see ice? Depends on the depth of the cad Link to comment Share on other sites More sharing options...
Deck Pic Posted February 14, 2016 Share Posted February 14, 2016 GFS is way west.... Link to comment Share on other sites More sharing options...
yoda Posted February 14, 2016 Share Posted February 14, 2016 GFS is way west.... Looks like 2-3? Link to comment Share on other sites More sharing options...
WinterWxLuvr Posted February 14, 2016 Share Posted February 14, 2016 I guess there's not much to say about the gfs. It seems it was only a matter of time before it decided to run the low up the west side of the apps. Link to comment Share on other sites More sharing options...
MacintoshPro Posted February 14, 2016 Share Posted February 14, 2016 GFS is weak sauce. Looks like 1-2" before a change to ZR. Keeps the heavier precipitation to South/Central VA, like the NAM Link to comment Share on other sites More sharing options...
clskinsfan Posted February 14, 2016 Share Posted February 14, 2016 The RGEM weenie map actually looks very similar to the 4k map through 48. The NAM gets the precip in a little earlier. But they are pretty similar overall. And the GFS is a horrific debacle. Link to comment Share on other sites More sharing options...
Deck Pic Posted February 14, 2016 Share Posted February 14, 2016 GFS is weak sauce. Looks like 1-2" before a change to ZR. Keeps the heavier precipitation to South/Central VA, like the NAM it's a huge shift in 6 hours....doesn't change a whole lot on the front...but accentuates the risk that the front end could be wimpy. Link to comment Share on other sites More sharing options...
SLPressure Posted February 14, 2016 Share Posted February 14, 2016 GFS is way west.... Wow! West Virginia runner. Long live the King or just a hiccup? Link to comment Share on other sites More sharing options...
yoda Posted February 14, 2016 Share Posted February 14, 2016 So we have for snowfall: 4km NAM 4-6, NAM/RGEM 2-4... GFS 1-3... that sound about right? Link to comment Share on other sites More sharing options...
WinterWxLuvr Posted February 14, 2016 Share Posted February 14, 2016 GFS is weak sauce. Looks like 1-2" before a change to ZR. Keeps the heavier precipitation to South/Central VA, like the NAM GFS is a totally different scenario now. That low going up the west side of the apps isn't all that shocking. It won't be shocking if the next run has it on the east side. Link to comment Share on other sites More sharing options...
MacintoshPro Posted February 14, 2016 Share Posted February 14, 2016 GFS isn't totally different for DC. Still light overrunning snows with a bit of ZR then driving rain. Looks like 12z and 06z. I'm not sure the further west track really affected the outcome. Link to comment Share on other sites More sharing options...
MacintoshPro Posted February 14, 2016 Share Posted February 14, 2016 GFS has us in the low 50s Tuesday, while the NAM has us in the low 30s Link to comment Share on other sites More sharing options...
CAPE Posted February 14, 2016 Share Posted February 14, 2016 I noticed the NAVGEM shifted its track west of the mountains at 18z...but meh its the NAVGEM. Now the GFS does it lol. Link to comment Share on other sites More sharing options...
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