HurricaneTracker Posted November 25, 2014 Share Posted November 25, 2014 Here is my first call map, might need to update it sometime tomorrow. Nice!. I think this is an excellent first call map for snow. Some additional things too watch: 1. Models trending a tad wetter. Perhaps an extra tenth or so of liquid. This could be another .5" to 1" of snow. Euro still shows .70" of liquid tho is on the high end of its own ensembles. If it verifies, could squeak out another inch. 2. Timing. Most, if not all the snow, falls by 12Z Wednesday. I have examined the soundings closely and I think anyone above 2100' will see snow. See my earlier post for that detail. If the system slows down then it makes a later onset and increases the chance of much more rain than snow. I look forward to seeing an updated map tomorrow following the 00 and 12Z guidance!. Good luck to all! Link to comment Share on other sites More sharing options...
Hvward Posted November 25, 2014 Share Posted November 25, 2014 Nice!. I think this is an excellent first call map for snow. Some additional things too watch: 1. Models trending a tad wetter. Perhaps an extra tenth or so of liquid. This could be another .5" to 1" of snow. Euro still shows .70" of liquid tho is on the high end of its own ensembles. If it verifies, could squeak out another inch. 2. Timing. Most, if not all the snow, falls by 12Z Wednesday. I have examined the soundings closely and I think anyone above 2100' will see snow. See my earlier post for that detail. If the system slows down then it makes a later onset and increases the chance of much more rain than snow. I look forward to seeing an updated map tomorrow following the 00 and 12Z guidance!. Good luck to all! Thanks HT! I am looking back now, have been at work all day! The timing should be nice for us. It will be awesome to see some big flakes falling! BTW 0z NAM trending wetter .41" of precip @ hr33 which would be 4am and total precip of .5-.75 in northern Buncombe and .75-1" in southern Buncombe and Northern Henderson co. This could be setting up for a fun event. Link to comment Share on other sites More sharing options...
franklin NCwx Posted November 25, 2014 Share Posted November 25, 2014 Nam just came in wetter and colder! 21z sref is 3 inches for both franklin and asheville. Link to comment Share on other sites More sharing options...
jacobr57 Posted November 25, 2014 Share Posted November 25, 2014 Thanks HT! I am looking back now, have been at work all day! The timing should be nice for us. It will be awesome to see some big flakes falling! BTW 0z NAM trending wetter .41" of precip @ hr33 which would be 4am and total precip of .5-.75 in northern Buncombe and .75-1" in southern Buncombe and Northern Henderson co. This could be setting up for a fun event. The NAM was much wetter this run. I'm crossing my fingers for you guys in Asheville and north! I'm afraid I might be fringed down in Hendersonville. Link to comment Share on other sites More sharing options...
jacobr57 Posted November 25, 2014 Share Posted November 25, 2014 Thought you guys might be interested in this: Link to comment Share on other sites More sharing options...
griteater Posted November 25, 2014 Share Posted November 25, 2014 I'm going to be at 3500 ft near Spruce Pine tomorrow night. Looking at GFS (18z) and NAM (00z) soundings for downtown Asheville, I'm seeing the wet bulb zero height around 3800-4000ft, dropping to 3300-3800ft, with surface wet bulbs in the 37>35 degree range. That would imply rain to rain/snow mix to me. Are folks thinking it will be colder than the verbatim soundings? Seems like the Euro may be a touch colder. Opinions? This run of the NAM was a little warmer for downtown Asheville (on the soundings). Link to comment Share on other sites More sharing options...
wncsnow Posted November 25, 2014 Share Posted November 25, 2014 I'm going to be at 3500 ft near Spruce Pine tomorrow night. Looking at GFS (18z) and NAM (00z) soundings for downtown Asheville, I'm seeing the wet bulb zero height around 3800-4000ft, dropping to 3300-3800ft, with surface wet bulbs in the 37>35 degree range. That would imply rain to rain/snow mix to me. Are folks thinking it will be colder than the verbatim soundings? Seems like the Euro may be a touch colder. Opinions? This run of the NAM was a little warmer for downtown Asheville (on the soundings). Are you the poster with the property on seven mile ridge? My dads side of the family grew up there and I still have an uncle who lives there Link to comment Share on other sites More sharing options...
griteater Posted November 25, 2014 Share Posted November 25, 2014 Are you the poster with the property on seven mile ridge? My dads side of the family grew up there and I still have an uncle who lives there Cool, my in laws live up there Link to comment Share on other sites More sharing options...
wncsnow Posted November 25, 2014 Share Posted November 25, 2014 Cool, my in laws live up there Nice, I love the south toe river area, has some interesting microclimates. I think seven mile ridge does well with this setup 3-6 inches definitely possible Link to comment Share on other sites More sharing options...
griteater Posted November 25, 2014 Share Posted November 25, 2014 Nice, I love the south toe river area, has some interesting microclimates. I think seven mile ridge does well with this setup 3-6 inches definitely possible Thanks, it's neat having that extra bit of cooling up on the ridge....but man, it keeps trending a little warmer...00z GFS looks too warm even up there to me. The airmass that we start with is just so marginal Link to comment Share on other sites More sharing options...
wncsnow Posted November 25, 2014 Share Posted November 25, 2014 Thanks, it's neat having that extra bit of cooling up on the ridge....but man, it keeps trending a little warmer...00z GFS looks too warm even up there to me. The airmass that we start with is just so marginal Yea, the GFS looks pretty awful for all of the mountains, it very well could be a rate driven thing even at your elevation. I would still be surprised if you don't get at least an inch or 2 Link to comment Share on other sites More sharing options...
Met1985 Posted November 25, 2014 Author Share Posted November 25, 2014 Great analysis guys! Looking back at the GFS last night that would not be good for us at all. We would barely get anything out of that solution. Not sure on the overnight Euro but this mornings NAM keeps on impressing me. It comes in at some pretty decent totals for the first wave. I could see a 2-4 inch snowfall for several areas out of this. Also the second wave for Thanksgiving day keeps on looking better and better, Could be some nice upslope snowfall along the boarder counties. I do think we start off as rain first. Basically all the models are hinting at this and I think it is a sure thing, Then the Cold air bleed down the mountains. The higher you are the better you are. Grit I would think you will be in a good spot. Link to comment Share on other sites More sharing options...
Tacoma Posted November 25, 2014 Share Posted November 25, 2014 WWA advisories were just issued for Buncombe County, Madison County, Haywood County and Transyalvania County and a few others and then around Boone Winter Storm Warning. Link to comment Share on other sites More sharing options...
Hvward Posted November 25, 2014 Share Posted November 25, 2014 Great analysis guys! Looking back at the GFS last night that would not be good for us at all. We would barely get anything out of that solution. Not sure on the overnight Euro but this mornings NAM keeps on impressing me. It comes in at some pretty decent totals for the first wave. I could see a 2-4 inch snowfall for several areas out of this. Also the second wave for Thanksgiving day keeps on looking better and better, Could be some nice upslope snowfall along the boarder counties. I do think we start off as rain first. Basically all the models are hinting at this and I think it is a sure thing, Then the Cold air bleed down the mountains. The higher you are the better you are. Grit I would think you will be in a good spot. NAM QPF continues to increase and is very impressive like you stated. The shortwave that also follows could over perform. All and all I like the setup and hope to see the NAM continue to trend wetter. Has most of Buncombe Co. in the .75"-1" territory. Link to comment Share on other sites More sharing options...
HurricaneTracker Posted November 25, 2014 Share Posted November 25, 2014 WWA advisories were just issued for Buncombe County, Madison County, Haywood County and Transyalvania County and a few others and then around Boone Winter Storm Warning. Be forewarned - GSP issues this WWA for elevations above 3500' in all of these counties. This suggests no measurable snow in the valleys at all. Will need to take a closer look at the soundings to see what happened, but GFS is all rain while NAM is going bonkers. My experience in these differing model solutions is that the GFS almost always wins around here... Link to comment Share on other sites More sharing options...
SnoJoe Posted November 25, 2014 Share Posted November 25, 2014 This is going to be a nail bitter for sure. YANCEY-MITCHELL-INCLUDING THE CITIES OF...BURNSVILLE...SPRUCE PINE433 AM EST TUE NOV 25 2014...WINTER WEATHER ADVISORY IN EFFECT FROM 9 PM THIS EVENING TO4 PM EST WEDNESDAY...THE NATIONAL WEATHER SERVICE IN GREENVILLE-SPARTANBURG HAS ISSUEDA WINTER WEATHER ADVISORY FOR SNOW...WHICH IS IN EFFECT FROM 9 PMTHIS EVENING TO 4 PM EST WEDNESDAY.* LOCATIONS...YANCEY AND MITCHELL COUNTIES IN NORTH CAROLINA.* HAZARDS...ACCUMULATING SNOWFALL.* TIMING...CHANCES INCREASING BY LATE EVENING...SNOW CONTINUINGOVERNIGHT INTO WEDNESDAY MORNING...BEFORE TAPERING OFF BYAFTERNOON.* ACCUMULATIONS...1 TO 4 INCHES...LOCALLY HIGHER AMOUNTS POSSIBLEIN THE HIGHER ELEVATIONS.* IMPACTS...SNOW ACCUMULATING ON ROADS COULD RESULT IN HAZARDOUSDRIVING CONDITIONS.* TEMPERATURES...LOWER TO MID 30S. Link to comment Share on other sites More sharing options...
HurricaneTracker Posted November 25, 2014 Share Posted November 25, 2014 A quick look at GFS and NAM soundings for Asheville suggest a complete night and day difference between the two. GFS never has a snow sounding, with surface temps in the upper 30s the entire time and 850mb temps at zero. Meanwhile, NAM is much colder, down to 32 at the surface and a classic heavy wet snow sounding with nearly isothermal layer say 800-600mb. Classic. Now...anybody have any thoughts on model performance? FWIW, the 00Z Euro came in with almost all rain as well. Link to comment Share on other sites More sharing options...
Hvward Posted November 25, 2014 Share Posted November 25, 2014 A quick look at GFS and NAM soundings for Asheville suggest a complete night and day difference between the two. GFS never has a snow sounding, with surface temps in the upper 30s the entire time and 850mb temps at zero. Meanwhile, NAM is much colder, down to 32 at the surface and a classic heavy wet snow sounding with nearly isothermal layer say 800-600mb. Classic. Now...anybody have any thoughts on model performance? FWIW, the 00Z Euro came in with almost all rain as well. Yeah euro ensemble was very different compared to deterministic. Only obs I have is that the gfs last night had mby at 47 this morning and my low was 42. This one is going to be a nail bitter like joe said. Also a nice stratus deck over the valley this morning. Would think that should keep temps down a bit today but I am just wishing I think. Link to comment Share on other sites More sharing options...
franklin NCwx Posted November 25, 2014 Share Posted November 25, 2014 Gfs is a furnace nam is a snow sounding. Link to comment Share on other sites More sharing options...
franklin NCwx Posted November 25, 2014 Share Posted November 25, 2014 leaving the house with 37degree looks like mostly cloudy Link to comment Share on other sites More sharing options...
Hvward Posted November 25, 2014 Share Posted November 25, 2014 Night and day on Bufkit. 06z NAM 06z GFS Link to comment Share on other sites More sharing options...
HurricaneTracker Posted November 25, 2014 Share Posted November 25, 2014 Yeah euro ensemble was very different compared to deterministic. Only obs I have is that the gfs last night had mby at 47 this morning and my low was 42. This one is going to be a nail bitter like joe said. Also a nice stratus deck over the valley this morning. Would think that should keep temps down a bit today but I am just wishing I think. Yea, really need to get a handle on these 2m temps. I do believe NAM has done better with those so far this season. Even then, aloft above the surface, both models are so very far apart. Let's hope this gets rectified at 12Z. Link to comment Share on other sites More sharing options...
griteater Posted November 25, 2014 Share Posted November 25, 2014 A quick look at GFS and NAM soundings for Asheville suggest a complete night and day difference between the two. GFS never has a snow sounding, with surface temps in the upper 30s the entire time and 850mb temps at zero. Meanwhile, NAM is much colder, down to 32 at the surface and a classic heavy wet snow sounding with nearly isothermal layer say 800-600mb. Classic. Now...anybody have any thoughts on model performance? FWIW, the 00Z Euro came in with almost all rain as well. Hard to envision the NAM beating a Euro/GFS combo Link to comment Share on other sites More sharing options...
franklin NCwx Posted November 25, 2014 Share Posted November 25, 2014 Sref held serve here for just overy 2 inches, most give at least an inch. Lol at the plumes for asheville. There are two camps, either asheville gets 6+ or Nothing. Link to comment Share on other sites More sharing options...
franklin NCwx Posted November 25, 2014 Share Posted November 25, 2014 Hug the nam Link to comment Share on other sites More sharing options...
griteater Posted November 25, 2014 Share Posted November 25, 2014 Hi Res NMM simulation... Link to comment Share on other sites More sharing options...
griteater Posted November 25, 2014 Share Posted November 25, 2014 NAM soundings are warmer compared to 6z, but seem to crash a little faster with the heavier precip Link to comment Share on other sites More sharing options...
HurricaneTracker Posted November 25, 2014 Share Posted November 25, 2014 Well, GFS came in and it continues to look very warm for the mountains. Meanwhile, the 12Z NAM holds serve and is much colder at the surface (and aloft!) and suggests a good 6-hour window of snow in AVL. So it comes down to which sounding looks most realistic, taking into account known model biases. NAM at 12Z Wednesday, showing a classic SNOW sounding: GFS at 12Z Wednesday showing a deep warm layer near the surface (i.e., rain): Note their differences, especially at 850mb, which the GFS is a good 2 degrees warmer than the NAM. Both have a very similar look upstairs at 500mb, so I am having a hard time finding reasons why the NAM is so cold (or the GFS so warm). It is at such instances where a blend of the two models is most likely what any forecaster would do, since both NAM and GFS could be right solutions. So my final call for AVL is 0.7" of very slushy snow, no road or travel issues, and all melting in the afternoon. This should fall between 5am and 8am. This is based upon two things: 1) how mild it has been the last few days and 2) typically around here, once an event starts as rain, it is tremendously difficult to get it to switch over to snow in setups like this. This is an event that starts as rain - all models agree upon that. The NAM simply cools the column more due to stronger forcing (i.e., rates), whereas the GFS (and Euro, really) has much lighter precip and not as high total QPF. Even for higher elevations, GFS implies snow level is at or above 5000'. I will happily eat crow if my forecast crashes and burns (and the NAM verifies!). But thought I would share my reasoning. Cheers! Link to comment Share on other sites More sharing options...
wncsnow Posted November 25, 2014 Share Posted November 25, 2014 Sound reasoning, but I highly doubt areas above 3,000 ft have much trouble going over to snow, especially if the precip rates are increased. New GFS shows heavier precip compared to past few runs, although not quite as heavy as NAM Link to comment Share on other sites More sharing options...
franklin NCwx Posted November 25, 2014 Share Posted November 25, 2014 Sound reasoning, but I highly doubt areas above 3,000 ft have much trouble going over to snow, especially if the precip rates are increased. New GFS shows heavier precip compared to past few runs, although not quite as heavy as NAMthe only problem is its warm up to 5000ft. Link to comment Share on other sites More sharing options...
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