nzucker Posted January 13, 2011 Share Posted January 13, 2011 I think it is to early to say either way if this will be more wintry or more rainy. Flood threat does exist but that would depend on several factors included the current water content of the snow pack and its ability to absorb additional moisture, what surface temps would be if it was rain, ie rain and 35-40 vs 45-55 and what current river flow levels are. Regardless of all that a flood threat is one scenario to watch for just as an ice threat also is one to watch for especially north and west of NYC and PHI in the favored areas to CAD best. It doesn't look as if temperatures would warm much about 40F in this system...there is a good deal of CAD with the high moving off the coast, and we don't have a very strong surface low cutting to the west. Link to comment Share on other sites More sharing options...
Analog96 Posted January 13, 2011 Share Posted January 13, 2011 GFS Shows an inch or so Saturday with the Clipper, then 2-4" Monday night before we change over. Maybe those extra 3-5" (combined) help preserve our snowcover. Link to comment Share on other sites More sharing options...
Bluescat1 Posted January 13, 2011 Share Posted January 13, 2011 The one part that seems suspicious of an all Rain event is Mondays High is supposed to be in the low 30's before a storm comes tracking up coast where alot of Models have it taking a track up or near the benchmark..Let me say this if it was an all rain event on top of a snowpack followed by an Arctic freeze there would be some real problems with everything turning into a sheet of ice... I remember after the 93 storm they had to use front end loaders to remove the ice from our parking lot at work. Link to comment Share on other sites More sharing options...
Analog96 Posted January 13, 2011 Share Posted January 13, 2011 It doesn't look as if temperatures would warm much about 40F in this system...there is a good deal of CAD with the high moving off the coast, and we don't have a very strong surface low cutting to the west. That's part of it too, the absolute warmest I could see is probably 45 or so, and that would probably be brief. Link to comment Share on other sites More sharing options...
Analog96 Posted January 13, 2011 Share Posted January 13, 2011 That's part of it too, the absolute warmest I could see is probably 45 or so, and that would probably be brief. Also, there hasn't been much snow in the Poconos and Catskills, so runoff is not going to be much of a problem. Link to comment Share on other sites More sharing options...
Nikolai Posted January 13, 2011 Share Posted January 13, 2011 I don't think the prospects for the upcoming event are as bad as people are making them out to be. I'd take the solutions at hand with a major amount of salt for several reasons. We haven't seen the modeled track occur at all this winter, for one, and tracks do tend to repeat over the course of a winter. The high pressure is also rather impressive, and it wouldn't take much of a shift to get the low east of Labrador to shift into a more favorable position. This is an even more precarious setup when the northern stream is taken into account, given how many problems models have had modeling nrn stream events this year. I'd say the probability of a storm going too far west to give us appreciable QPF is higher than what's currently progged on the GFS. Link to comment Share on other sites More sharing options...
hudsonvalley21 Posted January 13, 2011 Share Posted January 13, 2011 GFS Shows an inch or so Saturday with the Clipper, then 2-4" Monday night before we change over. Maybe those extra 3-5" (combined) help preserve our snowcover. Do you think in areas north and west of NYC. There could be some CAD that could be tough to dislodge. The overnight lows are forcasted to be in the upper teens to low 20s. Might have some ice issues up this way. Link to comment Share on other sites More sharing options...
jdt Posted January 13, 2011 Share Posted January 13, 2011 That's part of it too, the absolute warmest I could see is probably 45 or so, and that would probably be brief. That is probably correct and thus unless it rains very heavy and quick I think the flood threat, on a large scale river and stream aspect, is probably minor. Of course street flooding due to blocked drains is another issue. I suspect the ice threat N&W is probably greater then the flood threat. Time will tell. Link to comment Share on other sites More sharing options...
IsentropicLift Posted January 13, 2011 Share Posted January 13, 2011 I've seen it before, it doesn' take a massive warm up to melt the snow pack when it's raining ontop of it. I'm not saying that we would loose all of it at once which would probably bring major flooding but the other factor is that it's been very cold as of late and the ground is frozen so that would cause alot of the rain to runoff rather than get absorbed. Also with the sun being out yesterday and today, the top layer of snow around here has been melting and then re-freezing at night, so that could make it harder for the snow to absorb the water. If you add a layer of ice ontop of the snow I would think that adds even more fuel to the fire. Link to comment Share on other sites More sharing options...
Analog96 Posted January 13, 2011 Share Posted January 13, 2011 Do you think in areas north and west of NYC. There could be some CAD that could be tough to dislodge. The overnight lows are forcasted to be in the upper teens to low 20s. Might have some ice issues up this way. Could be, but the problem is, the GFS has precipitation beginning Monday afternoon, so there won't be radiational cooling Monday night. It's all going to come down to how fast the high retreats. Link to comment Share on other sites More sharing options...
NortheastPAWx Posted January 13, 2011 Share Posted January 13, 2011 The GFS only maxes KAVP at 35*F on this run verbatim. With snowpack prior to the event and an apparent underestimation of CAD, the chance for an icestorm runs high in NEPA. http://wxweb.meteost...0&submit=submit All subject to change, of course. Link to comment Share on other sites More sharing options...
Analog96 Posted January 13, 2011 Share Posted January 13, 2011 I've seen it before, it doesn' take a massive warm up to melt the snow pack when it's raining ontop of it. I'm not saying that we would loose all of it at once which would probably bring major flooding but the other factor is that it's been very cold as of late and the ground is frozen so that would cause alot of the rain to runoff rather than get absorbed. Also with the sun being out yesterday and today, the top layer of snow around here has been melting and then re-freezing at night, so that could make it harder for the snow to absorb the water. If you add a layer of ice ontop of the snow I would think that adds even more fuel to the fire. You're talking about the snowpack as if it's all fresh snow. Underneath the snow that just fell, there is a layer of rock hard snow. That's not going anywhere fast. Link to comment Share on other sites More sharing options...
hudsonvalley21 Posted January 13, 2011 Share Posted January 13, 2011 Could be, but the problem is, the GFS has precipitation beginning Monday afternoon, so there won't be radiational cooling Monday night. It's all going to come down to how fast the high retreats. Thanks Link to comment Share on other sites More sharing options...
IsentropicLift Posted January 13, 2011 Share Posted January 13, 2011 You're talking about the snowpack as if it's all fresh snow. Underneath the snow that just fell, there is a layer of rock hard snow. That's not going anywhere fast. I see your point, I guess it will all come down to how much rain and how fast it falls but it does seem to be a prolonged event and one which will bring widespread heavy QPF. BTW, I'm refereing mostly to the Passaic River Basin which saw alot more snow than the Deleware. Ice storms around here just never seem to verify and the warm air always seems to work its way in faster than predicted but then again if we are talking about temps only making it to 35 I can see the ice issues. I would hope that a winter storm watch gets issued for this event if the ice threat looks real by Saturday. Link to comment Share on other sites More sharing options...
IsentropicLift Posted January 13, 2011 Share Posted January 13, 2011 BTW, how do dew points look for the event? Is it possible we could still get a wet snow at 35? Link to comment Share on other sites More sharing options...
Analog96 Posted January 13, 2011 Share Posted January 13, 2011 I see your point, I guess it will all come down to how much rain and how fast it falls but it does seem to be a prolonged event and one which will bring widespread heavy QPF. BTW, I'm refereing mostly to the Passaic River Basin which saw alot more snow than the Deleware. Ice storms around here just never seem to verify and the warm air always seems to work its way in faster than predicted but then again if we are talking about temps only making it to 35 I can see the ice issues. I would hope that a winter storm watch gets issued for this event if the ice threat looks real by Saturday. Also read what I said about runoff. The fact that snowfall has been below normal to our North and West will diminish flooding threats. Link to comment Share on other sites More sharing options...
Yes_Probably_Maybe_No Posted January 13, 2011 Share Posted January 13, 2011 I hope this trends weaker/faster. The clipper for this weekend was once modeled as a pretty big CAD event and now it'll only bring a snow shower or two (to Philly). Link to comment Share on other sites More sharing options...
Analog96 Posted January 13, 2011 Share Posted January 13, 2011 BTW, how do dew points look for the event? Is it possible we could still get a wet snow at 35? Absolutely not and it has nothing to do with dew points. At the start of the event, ALL levels, including the BL, are cold enough for snow. The upper levels will warm up before the surface, so wet snow at 35 is an absolute impossibility with this event. Link to comment Share on other sites More sharing options...
Zelocita Weather Posted January 13, 2011 Share Posted January 13, 2011 Also read what I said about runoff. The fact that snowfall has been below normal to our North and West will diminish flooding threats. I'm assuming GGEM is not good? Link to comment Share on other sites More sharing options...
Analog96 Posted January 13, 2011 Share Posted January 13, 2011 I hope this trends weaker/faster. The clipper for this weekend was once modeled as a pretty big CAD event and now it'll only bring a snow shower or two (to Philly). A Clipper would never be a CAD event. Link to comment Share on other sites More sharing options...
Analog96 Posted January 13, 2011 Share Posted January 13, 2011 I'm assuming GGEM is not good? To be honest, I didn't look at it. Link to comment Share on other sites More sharing options...
IsentropicLift Posted January 13, 2011 Share Posted January 13, 2011 Also read what I said about runoff. The fact that snowfall has been below normal to our North and West will diminish flooding threats. Well, with the flooding we got in March the snow pack was more or less gone except in upper Passaic/Sussex County. I'm a Firefighter and Morris County OEM estimated that the snowpack up their was holding about 9" of water. This was mostly due to the big noreaster we had in February which brought them about 40" of snow. I frequent West Milford and I can tell you personally that the snow pack up their is massive in some spots, and I have no idea what the water content is but their is 2-3' in most spots with piles all over the place 8-10' high where it was plowed. The water up their runs off into the Pequannock River which then dumps into the Pompton River which then dumps into the Passaic River. I've lived here all my life and everytime their has been a snow pack like we currently have it's been a game of Russian Roulette with the rain. Link to comment Share on other sites More sharing options...
jrodd321 Posted January 13, 2011 Share Posted January 13, 2011 I don't know, from what I've been hearing it sounds like the cold is hanging around longer and longer each run of the GFS. Maybe this event has a chance to keep trending a little weaker/south? Its still far out, and anything can happen this winter. Link to comment Share on other sites More sharing options...
hckyplayer8 Posted January 13, 2011 Share Posted January 13, 2011 http://www.meteo.psu.edu/~gadomski/CMC_12z/cmcloop.html GGEM looks like it agree's with last nights Euro run. Link to comment Share on other sites More sharing options...
Sundog Posted January 13, 2011 Share Posted January 13, 2011 Have we ever seen -50C 850's appear on the map? Link to comment Share on other sites More sharing options...
Yes_Probably_Maybe_No Posted January 13, 2011 Share Posted January 13, 2011 A Clipper would never be a CAD event. Yeah I know. The models 3-4 days ago had a much different setup though with a more potent northern stream and southern stream energy running around ahead of it. As you know now, there is no southern stream anymore and the northern stream energy is much less potent. I'm hoping we see something similar, but I'm not too optimistic and it appears to be the normal GFS game where it saw the storm but simply doesn't know when it'll occur. Link to comment Share on other sites More sharing options...
Noreaster07 Posted January 13, 2011 Share Posted January 13, 2011 12z GGEM Link to comment Share on other sites More sharing options...
jrodd321 Posted January 13, 2011 Share Posted January 13, 2011 Hard to tell, is this rain for us? Link to comment Share on other sites More sharing options...
jrodd321 Posted January 13, 2011 Share Posted January 13, 2011 http://www.meteo.psu...2z/cmcloop.html GGEM looks like it agree's with last nights Euro run. Disagree. By what Earthlight/Tombo said last night, the cold air was no where near any of us. The Canadian is very close to be a nice even for us. Cold air is close, but no cigar this run. Link to comment Share on other sites More sharing options...
NaoPos Posted January 13, 2011 Share Posted January 13, 2011 Hard to tell, is this rain for us? That would be correct. The dark grey line on the top right panel indicates no snow in SE PA. Link to comment Share on other sites More sharing options...
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