Nikolai Posted January 17, 2011 Share Posted January 17, 2011 5-10 mile band of ZR? where are you getting that idea from? The more I look at this, the more I think a significant ice event is becoming LIKELY for NW NJ and the Hudson Valley... Narrow stripe sounds better. But my point is, events that have been forecasted to have large amounts of ZR over large areas generally haven't panned out in recent years, with most of the forecasted ZR coming as sleet instad. Link to comment Share on other sites More sharing options...
IsentropicLift Posted January 17, 2011 Share Posted January 17, 2011 From past experiences, the line between little ice and some ice seems to always be 287 and the line between some ice and major ice seems to be Rt. 23 and if that ends up being the case, warnings will definitly be needed 20 miles west of the city. Link to comment Share on other sites More sharing options...
hudsonvalley21 Posted January 17, 2011 Share Posted January 17, 2011 Agreed. And the problem is that it's very hard to determine exactly where the ice/no ice line will set up, since a few tenths of a degree can make all the difference. If I were on shift at NWS today, I would rather overwarn for ice than underwarn. Could be a mess around KPOU with QPF at 1.40 per the NAM. http://68.226.77.253/text/NAM80km/NAM_Kpou.txt Link to comment Share on other sites More sharing options...
Stormlover74 Posted January 17, 2011 Share Posted January 17, 2011 Yeah but if we are talking strictly R/S line, precipe type, Ringwood is going to be more similar to Andover than MMU. Used to work in Parsippany for many years and while we got more snow than EWR, many times that 'Snow north and west of 287' didnt apply in that part of Morris county. Andover is way too far West. Link to comment Share on other sites More sharing options...
Quincy Posted January 17, 2011 Share Posted January 17, 2011 SREF probabilities: >0.5" precip - 95% for all of NJ, extreme eastern PA, NYC, SE NY state and all of CT >1.0" precip - 85% from PHL-NYC (narrow strip), then 50% covers almost all of NJ, NYC, SE NY state and MOST of CT. Link to comment Share on other sites More sharing options...
Parsley Posted January 17, 2011 Share Posted January 17, 2011 Would an earlier start mean more snow before a changeover? @ Parsley - What are you thinking for down this way, seems were on the fence (as usual) Just from my past 6 years living around here, events like this tend to changeover in our necks of the woods between 8am-10am. PTW tends to lose the cold air a few hours after PHL, its further north from PTW where its tough to scour out the coldest air. Just a guess based on what I see and a blend of the NAM and GFS surface temps. POTTSTOWN LIMERICK A KPTW NAM MOS GUIDANCE 1/17/2011 1200 UTC 12z-31 15z-33 18z-35 We'll see what the 12z GFS #'s look like. Probably a few degrees colder at each time stamp based on what people are saying. So middle of the road would be toward about 15z-16z between the 2 models. Link to comment Share on other sites More sharing options...
IsentropicLift Posted January 17, 2011 Share Posted January 17, 2011 Total 84hr accumulations per the 12z NAM for each type of precip. Indicates 1-2" of plain rain from I-95 south and east. Less than 0.2" of snow for most of the area except up to 0.4" OPF of snow for the north philly burbs and Orange County and then 1"+ QPF points north. Virtually no sleet and then a pocket of between 0.10" to locally 0.50"+ of freezing rain centered over Northern NJ, portions of the lower hudson valley with a bullseye near West Milford, Warwick area. Sounds quite reasonable ATM. Link to comment Share on other sites More sharing options...
Quincy Posted January 17, 2011 Share Posted January 17, 2011 even as icy as the NAM is, the cold will likely be underestimated. the question in my mind is, are the temps a modest 1-2F colder, or are they even colder? I have seen a few ice events where the forecast is mid 30s and temps get stuck in the upper 20s. I'm liking the track of the low, but we need those NE to N winds to really kick in. Link to comment Share on other sites More sharing options...
IsentropicLift Posted January 17, 2011 Share Posted January 17, 2011 Latest from Mt. Holly, sounds like they don't know who to believe on this one... NEAR TERM /UNTIL 6 PM THIS EVENING/... -- Changed Discussion --NO BIG CHANGES WERE MADE WITH THE 11 AM SHORT TERM UPDATE. AS FAR AS THE 12Z INITIALIZATION WENT, THE GFS LOOKED BETTER THAN THE NAM OVERALL, ALTHOUGH BOTH MODELS DID NOT SHOW ANY GLARING ERRORS. THE 500MB TROF WAS NOT AS SHARP OVER LOUISIANA AS DEPICTED BY THE NAM ON ITS INITIALIZATION, MAYBE MAKING FOR A WIDER TURN FOR THE SURFACE LOW. THE GFS CAPTURED THE 850MB TEMP FIELD BETTER THAN THE NAM, ALTHOUGH NO MODEL IS AS COLD AS THE IAD SOUNDING AND IN GENERAL 850MB TEMPS ARE COLDER (ABOUT 1C) THAN MODEL INITIALIZATIONS TO OUR IMMEDIATE S. THE GFS INITIALIZED QUITE WELL AT 925MB.-- End Changed Discussion -- Link to comment Share on other sites More sharing options...
goldstar Posted January 17, 2011 Share Posted January 17, 2011 even as icy as the NAM is, the cold will likely be underestimated. the question in my mind is, are the temps a modest 1-2F colder, or are they even colder? I have seen a few ice events where the forecast is mid 30s and temps get stuck in the upper 20s. I'm liking the track of the low, but we need those NE to N winds to really kick in. How do you see the current obs over the region today compared to the models? Thank you for your contribution to Americanwx! Link to comment Share on other sites More sharing options...
Analog96 Posted January 17, 2011 Share Posted January 17, 2011 Latest from Mt. Holly, sounds like they don't know who to believe on this one... NEAR TERM /UNTIL 6 PM THIS EVENING/... -- Changed Discussion --NO BIG CHANGES WERE MADE WITH THE 11 AM SHORT TERM UPDATE. AS FAR AS THE 12Z INITIALIZATION WENT, THE GFS LOOKED BETTER THAN THE NAM OVERALL, ALTHOUGH BOTH MODELS DID NOT SHOW ANY GLARING ERRORS. THE 500MB TROF WAS NOT AS SHARP OVER LOUISIANA AS DEPICTED BY THE NAM ON ITS INITIALIZATION, MAYBE MAKING FOR A WIDER TURN FOR THE SURFACE LOW. THE GFS CAPTURED THE 850MB TEMP FIELD BETTER THAN THE NAM, ALTHOUGH NO MODEL IS AS COLD AS THE IAD SOUNDING AND IN GENERAL 850MB TEMPS ARE COLDER (ABOUT 1C) THAN MODEL INITIALIZATIONS TO OUR IMMEDIATE S. THE GFS INITIALIZED QUITE WELL AT 925MB.-- End Changed Discussion -- WOW! Tony sounds like he's saying it could be colder than any model is showing! Link to comment Share on other sites More sharing options...
Quincy Posted January 17, 2011 Share Posted January 17, 2011 How do you see the current obs over the region today compared to the models? Thank you for your contribution to Americanwx! Temperatures are basically where they were forecast to be, BUT, daytime readings are barely rising right now. Definitely a good sign going into tonight. Link to comment Share on other sites More sharing options...
Quincy Posted January 17, 2011 Share Posted January 17, 2011 WOW! Tony sounds like he's saying it could be colder than any model is showing! It could be. I remember one ice storm that affected NJ a few years back...progged temps were in the mid-30s, but readings didn't even get over 30 in some areas. These ice events can definitely have some tricks up their sleeves, but only time will tell... Link to comment Share on other sites More sharing options...
Analog96 Posted January 17, 2011 Share Posted January 17, 2011 It could be. I remember one ice storm that affected NJ a few years back...progged temps were in the mid-30s, but readings didn't even get over 30 in some areas. These ice events can definitely have some tricks up their sleeves, but only time will tell... VD 2007? Link to comment Share on other sites More sharing options...
gravitylover Posted January 17, 2011 Share Posted January 17, 2011 Please be colder Snow is easier to shovel than sleet and freezing rain. Link to comment Share on other sites More sharing options...
Parsley Posted January 17, 2011 Share Posted January 17, 2011 New 12Z MOS numbers are out on the GFS http://www.weather.g...p/avnmosmap.php POTTSTOWN/LIMERICK KPTW GFS MOS GUIDANCE 1/17/2011 1200 UTC 12z-27 15z-30 18z-33 vs. 12Z NAM MOS GUIDANCE 12z-31 15z-33 18z-35 Link to comment Share on other sites More sharing options...
rygar Posted January 17, 2011 Share Posted January 17, 2011 I don't know, feel like we've been her before many times in the past few years (not so much last y ear). Anecdotal only, but it seems historically only a very small area does well with this type of storm, and the majority of us rapidly change from snow earlier than progged, and then from ZR to rain earlier than expected. Link to comment Share on other sites More sharing options...
Quincy Posted January 17, 2011 Share Posted January 17, 2011 VD 2007? probably was. surface charts show a much different scenario, as a more wound up low tracked RIGHT along the coastline. I think the track of this low is important. with the low passing east of ACY and east of LI, it's really going to be difficult to get much warm air to work in away from the immediate shoreline. Link to comment Share on other sites More sharing options...
Quincy Posted January 17, 2011 Share Posted January 17, 2011 WOW. big surprise - new MAV MOS has a high of only 31 at Danbury! I did not see that coming. Link to comment Share on other sites More sharing options...
phlwx Posted January 17, 2011 Share Posted January 17, 2011 GFS has its cold bias at work again it seems. I'd lean towards the NAM on temps IMBY and the GFS on QPF. The NAM is good at damming situ better than the GFS. I think in the end the NAM temp profile wins most MOS sites. Link to comment Share on other sites More sharing options...
IsentropicLift Posted January 17, 2011 Share Posted January 17, 2011 Looks like the best bet here is up to 0.10" of ice on a line from the NJ turnpike on south eastward up to Trenton. Then between 0.10" - 0.25" of ice on a line from west of the turnpike to the east of 287 and north of I-80. Then between 0.25"-0.50" on a line west of 287 and north of I-80. 0.50"+ with locally higher amounts possible in the highest elevations of Western Passaic County, Sussex County and the lower Hudson valley. Anybody else think thats reasonable? Link to comment Share on other sites More sharing options...
Parsley Posted January 17, 2011 Share Posted January 17, 2011 GFS has its cold bias at work again it seems. I'd lean towards the NAM on temps and the GFS on QPF. The NAM is good at damming situ better than the GFS. I think in the end the NAM temp profile wins most MOS sites. Agreed. Take a compromise of both the GFS and NAM (12z runs) and you are looking at changeover (freezing to non freezing precip.) times for SE PA...... around 12z PHL around 15z PTW around 16-17z RDG-UKT around 18z ABE Link to comment Share on other sites More sharing options...
jasonli18t Posted January 17, 2011 Share Posted January 17, 2011 only 23.4 degrees here on long island right now with a dewpoint of 9...I have seen many messy situations start out this way here on the north shore. We got 6 inches of sleet and over a half inch of zr back in VD 07. Link to comment Share on other sites More sharing options...
cut Posted January 17, 2011 Share Posted January 17, 2011 WOW. big surprise - new MAV MOS has a high of only 31 at Danbury! I did not see that coming. I am in Trumbull, right in the valley in which rt. 25 lies. I find that if the wind is E to SE the cold air gets carved out pretty easily, if the wind much north of Easterly, then the cold has some staying power. The orientation of the valley is the driving force I believe, as it opens up to the sound and Bridgeport. Looks like this one will be dicey. Link to comment Share on other sites More sharing options...
goldstar Posted January 17, 2011 Share Posted January 17, 2011 Is there a precedent for any particular model/sets of models to be able to handle these types of events with good verification of the CAD and timing of the changeovers? Link to comment Share on other sites More sharing options...
jasonli18t Posted January 17, 2011 Share Posted January 17, 2011 I am in Trumbull, right in the valley in which rt. 25 lies. I find that if the wind is E to SE the cold air gets carved out pretty easily, if the wind much north of Easterly, then the cold has some staying power. The orientation of the valley is the driving force I believe, as it opens up to the sound and Bridgeport. Looks like this one will be dicey. The sound is frigid right now...if you are going to warm it will be due to winds off the ocean. Water temps off the coast of new haven are down around 34 degrees, with water temps of 33-37 for basically the entire sound. Link to comment Share on other sites More sharing options...
dtk Posted January 17, 2011 Share Posted January 17, 2011 Is there a precedent for any particular model/sets of models to be able to handle these types of events with good verification of the CAD and timing of the changeovers? Yes, none of them handle it well Link to comment Share on other sites More sharing options...
atownwxwatcher Posted January 17, 2011 Share Posted January 17, 2011 All i can say for the ABE area is that we are suppose to hit a high of 27 today and go down to 19 tonight...As of 12 noon we are sitting 1 degree above our overnight low @ 20 currently...Dewpoint is 4. So it seems at least at this point in the game..we are colder then expected... Link to comment Share on other sites More sharing options...
phlwx Posted January 17, 2011 Share Posted January 17, 2011 All i can say for the ABE area is that we are suppose to hit a high of 27 today and go down to 19 tonight...As of 12 noon we are sitting 1 degree above our overnight low @ 20 currently...Dewpoint is 4. So it seems at least at this point in the game..we are colder then expected... http://www.nws.noaa.gov/cgi-bin/mos/getall.pl?sta=KABE the 12z GFS has you at 18 at 1 PM. You're going to blend between the NAM and GFS in all likelihood. Link to comment Share on other sites More sharing options...
Analog96 Posted January 17, 2011 Share Posted January 17, 2011 GFS has its cold bias at work again it seems. I'd lean towards the NAM on temps IMBY and the GFS on QPF. The NAM is good at damming situ better than the GFS. I think in the end the NAM temp profile wins most MOS sites. Yeah, great idea! Let's use the NAM MOS, which is showing a 7 degree spread between temps and dew points with heavy precipitation falling, because that always happens, right? Link to comment Share on other sites More sharing options...
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