Clinch Leatherwood Posted January 27, 2014 Share Posted January 27, 2014 Bottom line one model will bump NW and then fade back while another one jumps NW. As of right now the 18z GFS and 12z Euro are on board for approximately a coating to an inch around the canal with amounts increasing to potential advisory level snows over Nantucket. The 18z RGEM was a tick more robust than the 12z which would support the general coating to a few inches from NW to SE in coastal SE MA/Cape Cod. The 18z GEFS are a bit more amped than even the OP...which many times leads to a future tick NW in the operational model. I haven't seen the 12z Euro ENS....The 18z NAM backed off pushing the bar for one inch snows back towards ACK.Of note, models have struggled to the southwest with the most notable adjustment being a substantial increase in QPF up to the NW edge in the last day or two. It appears that what's happening is the models are trying to decide whether or not the precip shield will bend more ENE/NE after about the level of offshore NJ or will it continue more NE/NNE and graze coastal areas? Part of the problem is the energy ejecting out of Mexico which should slowly come into better focus tonight.I haven't paid a ton of mind to this other than the general trend. Taking a very, very basic look to me tonight it almost appeared that the 18z GFS may have overdone how fast that sw system was ejecting in Mexico vs it's earlier run (which was drier).So...we wait. The movement on both the 18z GFS and 12z Euro was significant vs the previous runs which is either a red flag for future potentially impactful changes...or as a "we toss" moment. We'll see in a few hours. Fear Leon.Taunton NWS has weighed in as well "TUESDAY NIGHT...MODELS HAVE TRENDED TOWARD A SLIGHTLY MORE AMPLIFIED UPSTREAM TROFAS SHORTWAVE ENERGY DIVES INTO THE LOWER MS VALLEY. OCEAN STORMSTILL FORECAST TO REMAIN WELL SE OF THE BENCHMARK BUT IT IS NOWCLOSER AND THERE IS AGREEMENT THAT NW EDGE OF PRECIP SHIELD WILLCLIP AT LEAST THE CAPE/ISLANDS. THERE IS NOW HIGH CONFIDENCE OFAT LEAST 0.10" QPF REACHING ACK AND NAM/ECMWF INDICATE 0.25" UP TOACK AND 0.10" UP TO THE CANAL. GEFS ENSEMBLES HAVE 50% PROB OF0.25" TO ACK. CONFIDENCE IS INCREASING IN AN ADVISORY SNOWFALLFOR ACK WITH MINOR ACCUM TO THE CANAL AND POSSIBLY FAR SE MA ANDCOASTAL RI ALTHOUGH THIS IS LESS CERTAIN. NAM IS INDICATING GOODMID LEVEL FRONTOGENESIS AND LIFT THROUGH THE FAVORABLE SNOW GROWTHREGION ACROSS THE CAPE/ISLANDS. THERE WILL BE A SHARP CUT OFF TOTHE PRECIP SO IT COULD REMAIN DRY JUST INLAND FROM THE CANAL...BUTANY SLIGHT SHIFT IN THE TRACK WILL BE CRITICAL TO MORE SNOW ORLITTLE IF ANY SNOW." Link to comment Share on other sites More sharing options...
Baroclinic Zone Posted January 27, 2014 Share Posted January 27, 2014 Yeah, Cape and Islands look to be getting some snow out of this. May just amount to a dusting/coating like the other day but should make our Cape contingent happy. I lump you in the Cape as you're right there. Link to comment Share on other sites More sharing options...
HoarfrostHubb Posted January 27, 2014 Share Posted January 27, 2014 UUU might be in on it too Link to comment Share on other sites More sharing options...
Clinch Leatherwood Posted January 27, 2014 Author Share Posted January 27, 2014 We're fighting a dry wind with this one. We will need the moisture to get a little further NW than normal to produce. It's a real toss up....at first bluff it looks like it should stay progressive and mostly miss but then there's the argument that it will sharpen up enough just in time. 0z models should tell the tale. Link to comment Share on other sites More sharing options...
jamesnichols1989 Posted January 28, 2014 Share Posted January 28, 2014 The behavior of the Northern and Southern stream shortwaves in question appear to be on par with the 12z model suite, no real changes which would make this go either way. Right now the southern stream shortwave is slower than its northern stream counterpart. Question is will the southern stream shortwave eject northeastward out ahead of the northern stream, or will it slow down some and wait for the following shortwave? Link to comment Share on other sites More sharing options...
Ginx snewx Posted January 28, 2014 Share Posted January 28, 2014 Met Phil 888 posted this in the SE thread might be important to you codders The baja ULL is an important player in the evolution of this event, but I think the more important observation is what is already happening. A stronger than modeled piece of vorticity is currently merging with the polar shortwave over NM/TX. Note that this feature previously didn't exist in the medium range up until 18 hours before today's 12z analysis and is likely playing at least some role in why we have seen a substantial shift northward with the precipitation over the last 36-48 hours as the merger of that vorticity with the large scale shortwave has allowed a deeper 500 hPa trough thats extended further west. Note the vortmax in AZ that is now merging with the larger scale trough... this matters! Link to comment Share on other sites More sharing options...
Clinch Leatherwood Posted January 28, 2014 Author Share Posted January 28, 2014 Met Phil 888 posted this in the SE thread might be important to you coddersThe baja ULL is an important player in the evolution of this event, but I think the more important observation is what is already happening. A stronger than modeled piece of vorticity is currently merging with the polar shortwave over NM/TX. Note that this feature previously didn't exist in the medium range up until 18 hours before today's 12z analysis and is likely playing at least some role in why we have seen a substantial shift northward with the precipitation over the last 36-48 hours as the merger of that vorticity with the large scale shortwave has allowed a deeper 500 hPa trough thats extended further west. Note the vortmax in AZ that is now merging with the larger scale trough... this matters! Steve yep can see this on the rap this afternoon as it relates out there. Also note the area in Mexico as it changed on the 12 vs 18 gfs. 0z rap continues to jack it up. Funny this is one area in the grid that still causes major issues even for the euro Link to comment Share on other sites More sharing options...
Modfan Posted January 28, 2014 Share Posted January 28, 2014 Met Phil 888 posted this in the SE thread might be important to you codders The baja ULL is an important player in the evolution of this event, but I think the more important observation is what is already happening. A stronger than modeled piece of vorticity is currently merging with the polar shortwave over NM/TX. Note that this feature previously didn't exist in the medium range up until 18 hours before today's 12z analysis and is likely playing at least some role in why we have seen a substantial shift northward with the precipitation over the last 36-48 hours as the merger of that vorticity with the large scale shortwave has allowed a deeper 500 hPa trough thats extended further west. Note the vortmax in AZ that is now merging with the larger scale trough... this matters! To us up here or just the Cape and Islands? Link to comment Share on other sites More sharing options...
Ginx snewx Posted January 28, 2014 Share Posted January 28, 2014 To us up here or just the Cape and Islands?cape maybe Newport New Bedford Link to comment Share on other sites More sharing options...
Clinch Leatherwood Posted January 28, 2014 Author Share Posted January 28, 2014 Btw the interesting thing to me is the interaction being more robust already has the rap running north of the more aggressive guidance. Link to comment Share on other sites More sharing options...
CoastalWx Posted January 28, 2014 Share Posted January 28, 2014 Models are pretty good so it's not like that s/w is a big surprise. In the grand scheme it won't do much other than the typical small bumps NW or SE. Link to comment Share on other sites More sharing options...
jamesnichols1989 Posted January 28, 2014 Share Posted January 28, 2014 If that is true, this could slow down the northern stream shortwave or speed up the southern stream shortwave for a potential phase in streams, however this is least likely. The SREFs mean SLP has it track just outside the benchmark with a pressure of around 1008mb. This is much stronger than the mean SLP was yesterday, about 8mb. Maybe this is being seen by guidance. Link to comment Share on other sites More sharing options...
CoastalWx Posted January 28, 2014 Share Posted January 28, 2014 SREFs ticked SE. Link to comment Share on other sites More sharing options...
jamesnichols1989 Posted January 28, 2014 Share Posted January 28, 2014 Not by a whole lot Scott. Still have the .1" of QPD line over the Canal. They got stronger with the surface low as it nears about 100 miles southeast of the benchmark. Link to comment Share on other sites More sharing options...
CoastalWx Posted January 28, 2014 Share Posted January 28, 2014 Not by a whole lot Scott. Still have the .1" of QPD line over the Canal. They got stronger with the surface low as it nears about 100 miles southeast of the benchmark. Goes into the category of the waffles. Link to comment Share on other sites More sharing options...
TauntonBlizzard2013 Posted January 28, 2014 Share Posted January 28, 2014 I've got 1 eye half open on this threat. It's going to take an epic short term model bust for this to be anything more than a dusting here. Even if it does move nw, there is a lot of dry to fight through. I do think the islands outer cape could be in for an inch or two or three maybe Link to comment Share on other sites More sharing options...
jamesnichols1989 Posted January 28, 2014 Share Posted January 28, 2014 Is anyone else having trouble with the NAM right now? NCEP site doesn't have the NAM on it for 00z run. Link to comment Share on other sites More sharing options...
Clinch Leatherwood Posted January 28, 2014 Author Share Posted January 28, 2014 Is anyone else having trouble with the NAM right now? NCEP site doesn't have the NAM on it for 00z run. It's a ton wetter down south vs it's 18 or 12z runs. Primarily due to the stuff Phil was talking about. Link to comment Share on other sites More sharing options...
CoastalWx Posted January 28, 2014 Share Posted January 28, 2014 It's more about this coming east quicker and not getting buried like we mentioned last night. The quicker the ULL in baja comes east..the better the chances of a stronger low. Link to comment Share on other sites More sharing options...
Clinch Leatherwood Posted January 28, 2014 Author Share Posted January 28, 2014 0z NAM a pretty significant reversal from the 18z Link to comment Share on other sites More sharing options...
Clinch Leatherwood Posted January 28, 2014 Author Share Posted January 28, 2014 It's more about this coming east quicker and not getting buried like we mentioned last night. The quicker the ULL in baja comes east..the better the chances of a stronger low. Yeah, we don't really want the same things as our counterparts in the SE. The new nAM looks good, it'll be in league with the 18z GFS and the 12z Euro. Link to comment Share on other sites More sharing options...
weathafella Posted January 28, 2014 Share Posted January 28, 2014 It's a ton wetter down south vs it's 18 or 12z runs. Primarily due to the stuff Phil was talking about. Pretty good through 36. Per nam you shovel. Or at least sweep. Link to comment Share on other sites More sharing options...
Clinch Leatherwood Posted January 28, 2014 Author Share Posted January 28, 2014 Nice little hit S&E and possibly all the way back to coastal CT and RI with some reasonable omega showing up on the NAM now. Link to comment Share on other sites More sharing options...
CoastalWx Posted January 28, 2014 Share Posted January 28, 2014 The NAM has a better s/w kink feature over PA which increases divergence and allows for WAA further north. You can see this at hr 33 near eastern PA. Link to comment Share on other sites More sharing options...
Clinch Leatherwood Posted January 28, 2014 Author Share Posted January 28, 2014 The NAM has a better s/w kink feature over PA which increases divergence and allows for WAA further north. You can see this at hr 33 near eastern PA. Yeah general .25 or so... canal east. accumulating snows up to Bob and just S&E of Ginxy. Link to comment Share on other sites More sharing options...
RUNNAWAYICEBERG Posted January 28, 2014 Share Posted January 28, 2014 don't see this often Link to comment Share on other sites More sharing options...
RUNNAWAYICEBERG Posted January 28, 2014 Share Posted January 28, 2014 The NAM has a better s/w kink feature over PA which increases divergence and allows for WAA further north. You can see this at hr 33 near eastern PA. yea, good difference from say the 12z gfs...if only the pv could drop the s/w in on the backside and not shove it off the coast as much. Link to comment Share on other sites More sharing options...
Clinch Leatherwood Posted January 28, 2014 Author Share Posted January 28, 2014 Pretty good through 36. Per nam you shovel. Or at least sweep. Be ironic if I shoveled from Winter Storm Leon after breaking your stones for weeks. Link to comment Share on other sites More sharing options...
Clinch Leatherwood Posted January 28, 2014 Author Share Posted January 28, 2014 Will need to see the rest of the suite but the NAM would bring accumulating snow to many in S&E New England, even CoastalWx would get some. Advisory level for the Cape up to about me, and maybe a warning for ACK. The NAM shifts everything NW from about VA/NC to us but it still doesn't quite pull everything far enough for a real smash...it's more like the best just clips ACK while the rest of us get less. Interesting. GFS and Euro were on the heavier bus first, let's see what they do this run as the NAM is a useless model when it comes to "trends". It's changed course now 3 times in the last 3 runs. Link to comment Share on other sites More sharing options...
CoastalWx Posted January 28, 2014 Share Posted January 28, 2014 I would be interested if I were Scott and points east. Doubtful anything here. Link to comment Share on other sites More sharing options...
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