heavy_wx Posted December 5, 2013 Share Posted December 5, 2013 I think MDT will see some snow Friday night but I do agree that it may not happen with enough precip left to do much in the way of accumulations. Most of the model guidance I've seen focuses the axis of heavier snows near or just north of Pittsburgh and runs it northeastward from there, actually leaving most of the central areas with more of a 1-2 type event. The Euro curiously has a much more expansive area of decent snowfall, covering much of Pennsylvania within it's 3 inch contour (except for a small portion of the north central and SE PA). Agreed, I think the higher terrain northwest of UNV has a better chance for advisory level snow. The Euro appeared to be a bit cooler and farther south with the heavier precip than the GFS. The GFS develops a slightly stronger low east of the Appalachians which generates a greater component of low-level flow parallel to the temperature gradient. This greater frontogenesis that results is likely why the GFS has a higher amount of QPF. However, it would be warm enough to cut down on the frozen precipitation southeast of the higher plateau region of central PA. Link to comment Share on other sites More sharing options...
NortheastPAWx Posted December 5, 2013 Share Posted December 5, 2013 Tuesday night forecast low is down to 9. Brrr. Link to comment Share on other sites More sharing options...
Rick G Posted December 5, 2013 Share Posted December 5, 2013 Tuesday night forecast low is down to 9. Brrr. Time to bring in the brass monkeys..... (favorite saying from MASH) Anyone else notice that the NWS is trying (at least from my perspective) to micromanage the warnings? It seems like they (Binghamton) try to end a warning before the last flake has fallen. Link to comment Share on other sites More sharing options...
Mallow Posted December 5, 2013 Share Posted December 5, 2013 NAM and many of the SREFS are warm with the second wave. A lot more of them are mostly rain now... Link to comment Share on other sites More sharing options...
easternsnowman Posted December 5, 2013 Share Posted December 5, 2013 boooo Just the nam up to it's usual nonsense! Although the further north the better. Link to comment Share on other sites More sharing options...
Atomixwx Posted December 5, 2013 Share Posted December 5, 2013 DT just illicited a very loud guffaw with a picture he posted of a midget cuddling a miniature pony lololol Link to comment Share on other sites More sharing options...
NortheastPAWx Posted December 5, 2013 Share Posted December 5, 2013 6z NAM is pretty much all rain. Link to comment Share on other sites More sharing options...
sauss06 Posted December 5, 2013 Share Posted December 5, 2013 6z NAM is pretty much all rain. yeah, i don't understand why it wants to warm the temps up. Looks to me like is in the 20s, then once the precip gets here it goes to the mid 30s? Link to comment Share on other sites More sharing options...
Eskimo Joe Posted December 5, 2013 Share Posted December 5, 2013 yeah, i don't understand why it wants to warm the temps up. Looks to me like is in the 20s, then once the precip gets here it goes to the mid 30s? Prolonged easterly / southeasterly fetch off the ocean. The source region is 50+ degree ocean water. Use NOAA Bouy 44009 for your water temperature information during snow storms. When it's above 40 degrees, you're going to have a hard time getting a real snow or ice scenario. Link to comment Share on other sites More sharing options...
Jmister Posted December 5, 2013 Share Posted December 5, 2013 The NAM and SREFs have been warm for the last several runs now. The precip type map shows the story of where accumulating snows are most likely to occur. Even the GFS has been downplaying the cooler wave (Friday night) and is mostly rain throughout much of the area. I think CTP's current forecast needs to be changed to reflect more liquid as right now it shows accumulating snow Friday night (at least for UNV). Monday's event still spells ice trouble for a lot of us, but only for a few hours as we all should get well above freezing as the low lifts northwest of us. Just a shame we couldn't get any of these waves to amplify along the longwave trough. They all just get strung out along the positively-tilted east side of the trough. But it's only early December so there's plenty ahead! Link to comment Share on other sites More sharing options...
heavy_wx Posted December 5, 2013 Share Posted December 5, 2013 The Euro is still a bit more favorable for snow near UNV. There is a layer around 800mb that is above freezing at 18z Friday but cools to freezing by 00z Saturday. Text output from the Euro shows 0.43 inches QPF between 00 and 06z. The differences between the Euro and the GFS are subtle. A slightly stronger surface low develops east of the Appalachians on the GFS which could be transporting warmer air aloft more efficiently than the Euro. The Euro develops more of its precip frontogenetically after the cold air is in place. The placement of the thermal boundary is pretty similar between the two models; the more key difference I think is the degree of frontogenesis going on during the colder air. The NAM is quite a bit different, placing the colder 1000-850 mb thicknesses a good 50 miles northwest of the Euro and GFS. Link to comment Share on other sites More sharing options...
JamieOber Posted December 5, 2013 Share Posted December 5, 2013 NAM seems to be a bit colder at 12Z, looks like about .25 that falls with 850s and surface at or below freezing for UNV. Link to comment Share on other sites More sharing options...
Mallow Posted December 5, 2013 Share Posted December 5, 2013 Honestly, I'm not just being a snow weenie here.... but given the option, I ALWAYS, ALWAYS choose the Euro over the NAM. I could probably count on one hand the number of times I've seen the NAM beat the Euro when they were clearly in two different camps. Link to comment Share on other sites More sharing options...
Mallow Posted December 5, 2013 Share Posted December 5, 2013 yeah, i don't understand why it wants to warm the temps up. Looks to me like is in the 20s, then once the precip gets here it goes to the mid 30s? Prolonged easterly / southeasterly fetch off the ocean. The source region is 50+ degree ocean water. Use NOAA Bouy 44009 for your water temperature information during snow storms. When it's above 40 degrees, you're going to have a hard time getting a real snow or ice scenario. The 06z NAM didn't have the second storm in yet. The "all rain" was in reference to the first potential snow event, and that storm is associated with northerlies at the surface. The second snow->ice event at hr 84 on the 06z NAM looks like it's going to resemble the other models. Link to comment Share on other sites More sharing options...
Mallow Posted December 5, 2013 Share Posted December 5, 2013 Honestly, I'm not just being a snow weenie here.... but given the option, I ALWAYS, ALWAYS choose the Euro over the NAM. I could probably count on one hand the number of times I've seen the NAM beat the Euro when they were clearly in two different camps. Basically, to me, it looks like the 850 0C line doesn't move because 850 flow is almost dead in an odd lull between the southern 850mb height gradient and the northern one. This prevents good westerlies from advecting in cooler 850s. But even with weak 850mb advection, it's possible to get the 850mb temperatures to cool dynamically, say with the vertical motion associated with frontogenesis. Perhaps the Euro just has better vertical motion than the NAM over "true central" PA. Link to comment Share on other sites More sharing options...
JamieOber Posted December 5, 2013 Share Posted December 5, 2013 The 06z NAM didn't have the second storm in yet. The "all rain" was in reference to the first potential snow event, and that storm is associated with northerlies at the surface. The second snow->ice event at hr 84 on the 06z NAM looks like it's going to resemble the other models. lol, yeah, saw that. One other thing, those easterly winds didn't really prevent last Tuesday from being an ice storm. It's quite significant for the LSV but less so up here. Link to comment Share on other sites More sharing options...
cfbaggett Posted December 5, 2013 Share Posted December 5, 2013 I am loath to believe the NAM and the SREFS and ignore the Euro. Low level Arctic air tends to overperform. This will be a very fresh and very cold air mass that will press hard. Look at temperatures in the Midwest this morning and the winds that are advecting them. Look at Cheyenne with an anomaly of -45 earlier this morning. The Euro ensemble means for the first event are: UNV: 6" IPT: 6" CXY: 2" AOO: 6" JST: 7" Subtract 1" from each for initial melting, add a range of +/-1", and you have my forecast. This event is similar to one that delivered 4.4" at UNV last year, a flat wave along a SW-NE tilted stationary front on January 16th. I recall that the NAM didn't fully comprehend it until 24 hours from the event occuring. The SREFS are just little baby NAMs that are born three hours after mommy NAM is released from the psych ward. As far as the Sunday evening/Monday event; the cold air will hang tough. We only managed 34F at UNV last week without an Arctic high to our north! I believe there will be areas in central PA that will be completely frozen for this event. So yes, I am optomistic. I can't help it. Link to comment Share on other sites More sharing options...
cfbaggett Posted December 5, 2013 Share Posted December 5, 2013 Honestly, I'm not just being a snow weenie here.... but given the option, I ALWAYS, ALWAYS choose the Euro over the NAM. I could probably count on one hand the number of times I've seen the NAM beat the Euro when they were clearly in two different camps. Basically, to me, it looks like the 850 0C line doesn't move because 850 flow is almost dead in an odd lull between the southern 850mb height gradient and the northern one. This prevents good westerlies from advecting in cooler 850s. But even with weak 850mb advection, it's possible to get the 850mb temperatures to cool dynamically, say with the vertical motion associated with frontogenesis. Perhaps the Euro just has better vertical motion than the NAM over "true central" PA. ^^^ Agree 100%. Link to comment Share on other sites More sharing options...
JamieOber Posted December 5, 2013 Share Posted December 5, 2013 I am loath to believe the NAM and the SREFS and ignore the Euro. Low level Arctic air tends to overperform. This will be a very fresh and very cold air mass that will press hard. Look at temperatures in the Midwest this morning and the winds that are advecting them. Look at Cheyenne with an anomaly of -45 earlier this morning. The Euro ensemble means for the first event are: UNV: 6" IPT: 6" CXY: 2" AOO: 6" JST: 7" Subtract 1" from each for initial melting, add a range of +/-1", and you have my forecast. This event is similar to one that delivered 4.4" at UNV last year, a flat wave along a SW-NE tilted stationary front on January 16th. I recall that the NAM didn't fully comprehend it until 24 hours from the event occuring. The SREFS are just little baby NAMs that are born three hours after mommy NAM is released from the psych ward. As far as the Sunday evening/Monday event; the cold air will hang tough. We only managed 34F at UNV last week without an Arctic high to our north! I believe there will be areas in central PA that will be completely frozen for this event. So yes, I am optomistic. I can't help it. holy ****, I literally lol'd at this. Link to comment Share on other sites More sharing options...
PennMan Posted December 5, 2013 Author Share Posted December 5, 2013 holy ****, I literally lol'd at this.Same here. I agree with the low probability of significant warming Monday with the antecedent airmass and strong high to the north. The valleys of Central PA might see 32.5° at best. Link to comment Share on other sites More sharing options...
Mallow Posted December 5, 2013 Share Posted December 5, 2013 holy ****, I literally lol'd at this. Ditto Link to comment Share on other sites More sharing options...
Jmister Posted December 5, 2013 Share Posted December 5, 2013 Nam has cooled down at 12z, so you can be almost certain the SREFs will follow. I do think the NAM/SREFs are inferior to the EURO and other globals, but it is good to see them cool down too. Let's see what the rest of the 12z suite does... And Cory, you should pick up your red tag! We all can vouch that you are a meteorologist and a damn good one at that! Link to comment Share on other sites More sharing options...
heavy_wx Posted December 5, 2013 Share Posted December 5, 2013 But even with weak 850mb advection, it's possible to get the 850mb temperatures to cool dynamically, say with the vertical motion associated with frontogenesis. Perhaps the Euro just has better vertical motion than the NAM over "true central" PA. Maybe, but the 12z NAM produces more QPF than the Euro. Also the 850 mb vertical velocities look to be similar with those on the Euro, maybe even a bit greater over central PA. The NAM also has a layer from 850 to 750 mb that is above freezing until 06z, after which both models end precipitation. Link to comment Share on other sites More sharing options...
sauss06 Posted December 5, 2013 Share Posted December 5, 2013 I'm starting to think that this is the most difficult storm/system that i have tried to keep up with and learn. Link to comment Share on other sites More sharing options...
cfbaggett Posted December 5, 2013 Share Posted December 5, 2013 Nam has cooled down at 12z, so you can be almost certain the SREFs will follow. I do think the NAM/SREFs are inferior to the EURO and other globals, but it is good to see them cool down too. Let's see what the rest of the 12z suite does... And Cory, you should pick up your red tag! We all can vouch that you are a meteorologist and a damn good one at that! Give me a couple more years, and then I will be able to add meteo to my name... I keep good company here at PSU, and I am continually amazed at how bright and gifted the students are here. Link to comment Share on other sites More sharing options...
Mallow Posted December 5, 2013 Share Posted December 5, 2013 Maybe, but the 12z NAM produces more QPF than the Euro. Also the 850 mb vertical velocities look to be similar with those on the Euro, maybe even a bit greater over central PA. The NAM also has a layer from 850 to 750 mb that is above freezing until 06z, after which both models end precipitation. Hmm. Wonder why the discrepancy, then... Link to comment Share on other sites More sharing options...
Itstrainingtime Posted December 5, 2013 Share Posted December 5, 2013 I'm starting to think that this is the most difficult storm/system that i have tried to keep up with and learn. I agree...but I'm also having a hard time following because there are 2 separate threats that are being lumped together in essentially the same discussion. Those of us in the LSV (and those going to the Steelers game) are keying in on Sunday, while those north and west are focused on Friday night. Some great discussion and analysis...just hard to figure which event some are discussing. Link to comment Share on other sites More sharing options...
djr5001 Posted December 5, 2013 Share Posted December 5, 2013 I am loath to believe the NAM and the SREFS and ignore the Euro. Low level Arctic air tends to overperform. This will be a very fresh and very cold air mass that will press hard. Look at temperatures in the Midwest this morning and the winds that are advecting them. Look at Cheyenne with an anomaly of -45 earlier this morning. The Euro ensemble means for the first event are: UNV: 6" IPT: 6" CXY: 2" AOO: 6" JST: 7" Subtract 1" from each for initial melting, add a range of +/-1", and you have my forecast. This event is similar to one that delivered 4.4" at UNV last year, a flat wave along a SW-NE tilted stationary front on January 16th. I recall that the NAM didn't fully comprehend it until 24 hours from the event occuring. The SREFS are just little baby NAMs that are born three hours after mommy NAM is released from the psych ward. As far as the Sunday evening/Monday event; the cold air will hang tough. We only managed 34F at UNV last week without an Arctic high to our north! I believe there will be areas in central PA that will be completely frozen for this event. So yes, I am optomistic. I can't help it. lets play find the front!! lol http://www.meteo.psu.edu/~fxg1/DEPHR/last.html http://www.meteo.psu.edu/~fxg1/DT24/t0.gif I do think sorta similar to last week that the areas that manage a changeover tomorrow night and keep this fresh snow on Saturday will see colder temperatures than the models are currently predicting and yes with a more established high lock in the colder air near the surface once again for Sunday/Monday unlike last week though... there will likely be a good bit of rain before a changeover instead of snow first then change over... will be interesting to see how easy the places that do changeover tomorrow accumulate As for warm sea surface temperatures... at the surface it impacts far eastern PA more than the Harrisburg region... I have seen in the past where a east/southeasterly wind pushes the cold air into the eastern side of the mountains and places like MDT wind up 5-10 degrees colder than Reading and east... aloft it certainly hurts any chance for snow and can warm 850mb level enough that if we see heavy periods of rain the warmer air can mix down to the surface a little... lighter rainfall and we could see temperatures close again for ice potential Link to comment Share on other sites More sharing options...
mupawxnut Posted December 5, 2013 Share Posted December 5, 2013 Any predictions for icing in Millersville, PA? Link to comment Share on other sites More sharing options...
NortheastPAWx Posted December 5, 2013 Share Posted December 5, 2013 "The SREFS are just little baby NAMs that are born three hours after mommy NAM is released from the psych ward." Forever quoted Link to comment Share on other sites More sharing options...
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