Mallow Posted December 5, 2013 Share Posted December 5, 2013 How are soundings looking for above 850mb this run? I agree it's much improved and if it comes down heavy enough, the snow might just make it down if the warm layer isn't too thick. I posted some soundings on the previous page for the grid point closest to the city of State College. Of course, that's the grid point to the northwest, and the one to the northeast is warmer. Link to comment Share on other sites More sharing options...
Mallow Posted December 5, 2013 Share Posted December 5, 2013 Lol, too late hopes are up!! Keep in mind that the clown map is showing accumulating snows for areas that aren't even shown getting any real snow on the 3-hourly plots. The algorithm seems to be a bit wonky. Link to comment Share on other sites More sharing options...
NeffsvilleWx Posted December 5, 2013 Share Posted December 5, 2013 People SE of the UNV-IPT corridor shouldn't get their hopes up based on this clown map (yet), but... Never do! Link to comment Share on other sites More sharing options...
MAG5035 Posted December 5, 2013 Share Posted December 5, 2013 How are soundings looking for above 850mb this run? I agree it's much improved and if it comes down heavy enough, the snow might just make it down if the warm layer isn't too thick. The cross section i took from Pit to Allentown was much warmer at that 850-700 level than the Euro, staying above freezing for the hours of best precip all the way back to about Johnstown's longitude and at or even slightly above 0ºC all the way back to Pittsburgh (esp hours 30-33). Pretty cold air does undercut below 850 and is likely supportive of sleet for JST and probabaly AOO and UNV. This cross section is basically a straight line from Pittsburgh to Allentown, so it could give a good indication of the column for places in between like Johnstown, Altoona, State College, and Harrisburg. I'd have to draw a different line for a better representation of northern places like Williamsport or southern places like York and Lancaster. Link to comment Share on other sites More sharing options...
canderson Posted December 5, 2013 Share Posted December 5, 2013 Never do! +1 Seriously, I only believe it'll snow when I see it sticking to my driveway. Link to comment Share on other sites More sharing options...
Jmister Posted December 5, 2013 Share Posted December 5, 2013 For UNV 18z NAM Cobb data has 0.63" of ZR after a lot of rain. The soundings themselves don't agree with this, but it is a very marginal setup. My guess is that the immediate State College area gets rain to sleet to a little snow at the end. We tend to change over to sleet earlier than expected with these situations, but hang on to the warm layer longer than expected. Link is here if you want to check out the closest location to you: http://www.meteor.iastate.edu/~ckarsten/cobb/cobb.php?model=namm&site=kunv Link to comment Share on other sites More sharing options...
JamieOber Posted December 5, 2013 Share Posted December 5, 2013 CTP snowmap has <1" for my area while CTP grids for Friday night continue to say snow, maybe mixed with sleet and zr..turning to all snow after 10pm with a half to three quarters of QPF. Same thing for places like Johnstown and State College. Somethins gotta give there, they should be issuing their afternoon updates shortly. The Euro has continued to be the most supportive model for a sizable snowfall in most of Central PA vs the other models that focus more on Western/NW PA. AccuPro's 3D cross section product helps alot with visualizing the progression of the cold air. I wish I could post a pic of it but thats a big no no. Taking a cross section from Pit across the state to Allentown using the Euro shows that the cold air undercuts west to east from about 850mb and lower first initially leaving the relatively warm layer from 850 to 700mb that has been discussed about. However that particular layer is cold enough (barely) to support snow all through the column when it counts at hours 36 and 42 for the central areas...probably at the expense of good snow ratios. Cold enough air at those levels don't quite get to the Sus Valley in time for very much snow, although the 0ºC isotherm is undercutting at about 925mb. This warmer layer between 850-700mb also makes for higher 1000-500mb thickness and thus you can't really use the traditional 540 line to place the rain/snow line. The 546 line might be a better one to use in this instance. Wonder if they'll change that now that there's not much model support. Never mind...just saw above that there is model support. Link to comment Share on other sites More sharing options...
Wmsptwx Posted December 5, 2013 Share Posted December 5, 2013 Lol, I'm not expecting anything more than a light coating at the end so we'll see what happens!! Link to comment Share on other sites More sharing options...
NeffsvilleWx Posted December 5, 2013 Share Posted December 5, 2013 Link is here if you want to check out the closest location to you: http://www.meteor.iastate.edu/~ckarsten/cobb/cobb.php?model=namm&site=kunv Thanks Jmister, I was trying to remember that link for my link dump on the last page. Link to comment Share on other sites More sharing options...
jm1220 Posted December 5, 2013 Share Posted December 5, 2013 The cross section i took from Pit to Allentown was much warmer at that 850-700 level than the Euro, staying above freezing for the hours of best precip all the way back to about Johnstown's longitude and at or even slightly above 0ºC all the way back to Pittsburgh (esp hours 30-33). Pretty cold air does undercut below 850 and is likely supportive of sleet for JST and probabaly AOO and UNV. This cross section is basically a straight line from Pittsburgh to Allentown, so it could give a good indication of the column for places in between like Johnstown, Altoona, State College, and Harrisburg. I'd have to draw a different line for a better representation of northern places like Williamsport or southern places like York and Lancaster. Ahh, so tons of sleet. Hopefully there's not a large ZR zone. Link to comment Share on other sites More sharing options...
2001kx Posted December 5, 2013 Share Posted December 5, 2013 For UNV 18z NAM Cobb data has 0.63" of ZR after a lot of rain. The soundings themselves don't agree with this, but it is a very marginal setup. My guess is that the immediate State College area gets rain to sleet to a little snow at the end. We tend to change over to sleet earlier than expected with these situations, but hang on to the warm layer longer than expected. Link is here if you want to check out the closest location to you: http://www.meteor.iastate.edu/~ckarsten/cobb/cobb.php?model=namm&site=kunv that shows 10" for dubois Link to comment Share on other sites More sharing options...
Jmister Posted December 5, 2013 Share Posted December 5, 2013 that shows 10" for dubois With the amount of precip it has falling after 21z Friday that would actually make sense. However, we all know the NAM is notorious for overdoing precip! Link to comment Share on other sites More sharing options...
Wmsptwx Posted December 5, 2013 Share Posted December 5, 2013 How's GFS looking? Link to comment Share on other sites More sharing options...
JamieOber Posted December 5, 2013 Share Posted December 5, 2013 Thanks Jmister, I was trying to remember that link for my link dump on the last page. You can also add this. It has all the levels: http://www.wxcaster.com/models_text.htm Easier to read than a skew-t, at least for me. Link to comment Share on other sites More sharing options...
JamieOber Posted December 5, 2013 Share Posted December 5, 2013 How's GFS looking? It looks great but I don't know about that warm layer...an expert can say better. Link to comment Share on other sites More sharing options...
Wmsptwx Posted December 5, 2013 Share Posted December 5, 2013 Yea, 850 line is awesome!! Looks like at the very least advisory level sleet/snow. Link to comment Share on other sites More sharing options...
NeffsvilleWx Posted December 5, 2013 Share Posted December 5, 2013 You can also add this. It has all the levels: http://www.wxcaster.com/models_text.htm Easier to read than a skew-t, at least for me. Awesome, thanks! Link to comment Share on other sites More sharing options...
MAG5035 Posted December 5, 2013 Share Posted December 5, 2013 It looks great but I don't know about that warm layer...an expert can say better. I"ll be able to say once I see the full suite of products. AccuPros rapid update has been screwy since they've released their new version of Accuweather Professional. I can see the basic stuff but I can't see the updated expanded pick of products like 700 temps, ptypes, accums, etc until the whole model run is complete. I used to be able to see all that stuff with the rapid update. At any rate 850mb def looks good.. might even be colder than the Euro. Link to comment Share on other sites More sharing options...
Mallow Posted December 5, 2013 Share Posted December 5, 2013 For UNV 18z NAM Cobb data has 0.63" of ZR after a lot of rain. The soundings themselves don't agree with this, but it is a very marginal setup. My guess is that the immediate State College area gets rain to sleet to a little snow at the end. We tend to change over to sleet earlier than expected with these situations, but hang on to the warm layer longer than expected. Link is here if you want to check out the closest location to you: http://www.meteor.iastate.edu/~ckarsten/cobb/cobb.php?model=namm&site=kunv Why? The NAM is the pretty much the warmest model (besides the SREFs, which are awful), and even it is marginal for snow. 18z GFS is even a bit colder than the 12z. Link to comment Share on other sites More sharing options...
Jmister Posted December 5, 2013 Share Posted December 5, 2013 Looking at the Skew-T for UNV, it is lots 'o sleet from 18z Fri to 00z Sat, but becoming snow not much after that. Link to comment Share on other sites More sharing options...
Jmister Posted December 5, 2013 Share Posted December 5, 2013 Here are skew-t's for 18z and 00z at UNV from 18z GFS: Link to comment Share on other sites More sharing options...
mupawxnut Posted December 5, 2013 Share Posted December 5, 2013 They suck any time, but in the winter they really suck. Especially in an area where most services are overhead and a lot of trees. Combine that with this country's substandard power grid, and you are talking trouble. Link to comment Share on other sites More sharing options...
Jmister Posted December 5, 2013 Share Posted December 5, 2013 Why? The NAM is the pretty much the warmest model (besides the SREFs, which are awful), and even it is marginal for snow. 18z GFS is even a bit colder than the 12z. Part of my reasoning is based on what I've seen happen in the past. My other reasoning is because I like to have low expectations and be surprised when we exceed them. Real scientific, I know. But the warming from 800-700mb is showing up on most models and that needs to be taken into account. But it is encouraging to see the models continue to cool all layers more and more. Also, what's with CTP's forecast? Less than 1/2" of snow and sleet?! That's a far cry from the forecast earlier today! Link to comment Share on other sites More sharing options...
Mallow Posted December 5, 2013 Share Posted December 5, 2013 Here are skew-t's for 18z and 00z at UNV from 18z GFS: Keep in mind those are for the point to the northeast! The point to the northwest looks even better. Link to comment Share on other sites More sharing options...
Wmsptwx Posted December 5, 2013 Share Posted December 5, 2013 Lol...is the GFS a sleet fest? The 850s looks solid and it has great precip! Link to comment Share on other sites More sharing options...
Mallow Posted December 5, 2013 Share Posted December 5, 2013 Part of my reasoning is based on what I've seen happen in the past. My other reasoning is because I like to have low expectations and be surprised when we exceed them. Real scientific, I know. But the warming from 800-700mb is showing up on most models and that needs to be taken into account. But it is encouraging to see the models continue to cool all layers more and more. Also, what's with CTP's forecast? Less than 1/2" of snow and sleet?! That's a far cry from the forecast earlier today! I donno, we had a storm kinda like this last year and it turned out to be almost all snow, if I remember correctly. Link to comment Share on other sites More sharing options...
NortheastPAWx Posted December 5, 2013 Share Posted December 5, 2013 So where are we at after the 18z models? I'm seeing like 2-3 different interpretations. Also, isn't the ECM typically worse in the short range than mid? Link to comment Share on other sites More sharing options...
Wmsptwx Posted December 5, 2013 Share Posted December 5, 2013 So where are we at after the 18z models? I'm seeing like 2-3 different interpretations. Also, isn't the ECM typically worse in the short range than mid? I agree man, I can't read models as well as the mets and I see everything from a high end advisory event to rain ending as a bit of snow being mentioned here. And it starts tomorrow Link to comment Share on other sites More sharing options...
Mallow Posted December 5, 2013 Share Posted December 5, 2013 So where are we at after the 18z models? I'm seeing like 2-3 different interpretations. Also, isn't the ECM typically worse in the short range than mid? GFS and NAM are both colder on their 18z runs than they were on their 12z runs. How much snow they give State College depends mostly on which product you look at, and which grid point as well. Both have trended towards the 12z Euro, which is mostly snow for us. If the Euro is worse in the short range than the mid, I haven't noticed it. It certainly still verifies better than most of the other models in my experience. But that's not to say it's guaranteed to win every storm. Link to comment Share on other sites More sharing options...
Mallow Posted December 5, 2013 Share Posted December 5, 2013 18z GFS ensembles are also much improved. Lots of cold members, only a couple warm ones. Link to comment Share on other sites More sharing options...
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