packbacker Posted January 16, 2013 Share Posted January 16, 2013 RPM certainly is eye candy given that this thing is just a few hours away. I can't help to think that some will feel some real heartbreak though when the actual event begins. All in all, this could be a win for the NAM. Took the other models (Euro, GFS) to the woodshed if any of this verifies. Can you post where you view that at? The NE folks said it did well with there storm. Link to comment Share on other sites More sharing options...
burgertime Posted January 16, 2013 Share Posted January 16, 2013 By hour 33 on the hi res NAM CLT west is all snow Link to comment Share on other sites More sharing options...
BIG FROSTY Posted January 16, 2013 Share Posted January 16, 2013 Our criteria may be higher than the Piedmont now after 2010...not sure. Yes that's possible! I thought about that too! Link to comment Share on other sites More sharing options...
Met1985 Posted January 16, 2013 Share Posted January 16, 2013 GSP official forecast for AVL is only 1-3", per their updated zone forecast. Personally, given the 18Z run of the NAM, I think this is way too conservative. Still feel 4-6" a good bet for downtown, with 8-12" likely across the Smokies and northward up the spine of the Apps. Thanks Hurricane. I think they are being a little too conservative also especailly this coming up from the south. This is how we get our big storms in the mountains. Link to comment Share on other sites More sharing options...
packbacker Posted January 16, 2013 Share Posted January 16, 2013 Th 4km HWRF is tick SE and a tick weaker through 24. Link to comment Share on other sites More sharing options...
valkhorn Posted January 16, 2013 Share Posted January 16, 2013 Accuweather is giving Knoxville 3-6", The Weather Channel puts us in a no snow hole, and the NAM is giving us 6". Morristown's official forecast is a half inch of snow, if any at all. Strange. Link to comment Share on other sites More sharing options...
chapelhillwx Posted January 16, 2013 Share Posted January 16, 2013 Th 4km HWRF is tick SE and a tick weaker through 24. Where do you access that? I can't find it for the life of me. Thanks! Link to comment Share on other sites More sharing options...
ncwinterwxman Posted January 16, 2013 Share Posted January 16, 2013 The better performance of the NAM is to be expected given its high resolution and the convective scheme that is used. Inside of 48 hours out, the NAM is by far one of the best performing models MOST of the time and so really and truly I don't know why people even look at the global models (GFS, Euro, CMC) when forecasting inside of 48 hours out. RPM certainly is eye candy given that this thing is just a few hours away. I can't help to think that some will feel some real heartbreak though when the actual event begins. All in all, this could be a win for the NAM. Took the other models (Euro, GFS) to the woodshed if any of this verifies. Link to comment Share on other sites More sharing options...
SnowGoose69 Posted January 16, 2013 Share Posted January 16, 2013 The SPC WRF which I've found does a remarkable job on these events alot of the time supports WXSouth's idea that NRN GA could get pounded, very close to ATL as well. Link to comment Share on other sites More sharing options...
Met1985 Posted January 16, 2013 Share Posted January 16, 2013 AVERY-MADISON-YANCEY-MITCHELL-HAYWOOD-BUNCOMBE- INCLUDING THE CITIES OF...NEWLAND...SPRUCE PINE...WAYNESVILLE... ASHEVILLE WINTER STORM WARNING IN EFFECT FROM 1 PM THURSDAY TO MIDNIGHT EST THURSDAY NIGHT... THE NATIONAL WEATHER SERVICE IN GREENVILLE-SPARTANBURG HAS ISSUED A WINTER STORM WARNING FOR HEAVY SNOW...WHICH IS IN EFFECT FROM 1 PM THURSDAY TO MIDNIGHT EST THURSDAY NIGHT. THE WINTER STORM WATCH IS NO LONGER IN EFFECT. * LOCATIONS...THE CENTRAL AND NORTHERN MOUNTAINS OF NORTH CAROLINA. * HAZARDS...HEAVY SNOW. * TIMING...A TRANSITION FROM RAIN TO SNOW IS EXPECTED BY THURSDAY AFTERNOON. * ACCUMULATIONS...SNOW ACCUMULATION OF 4 TO 8 INCHES AT HIGHER ELEVATIONS. ACCUMULATIONS IN THE VALLEYS OF 2 TO 4 INCHES. * IMPACTS...SNOWFALL CREATING HAZARDOUS DRIVING CONDITIONS. HEAVY WET SNOW COMBINED WITH GUSTY WINDS MAY KNOCK DOWN TREES AND PULL DOWN POWER LINES IN SOME AREAS. * TEMPERATURES...FALLING INTO THE LOWER 30S BY LATE AFTERNOON. * WINDS...NORTH 10 TO 20 MPH WITH GUSTS UP TO 35 MPH. PRECAUTIONARY/PREPAREDNESS ACTIONS... A WINTER STORM WARNING FOR HEAVY SNOW MEANS SEVERE WINTER WEATHER CONDITIONS ARE EXPECTED OR OCCURRING. SIGNIFICANT AMOUNTS OF SNOW ARE FORECAST THAT WILL MAKE TRAVEL DANGEROUS. ONLY TRAVEL IN AN EMERGENCY. IF YOU MUST TRAVEL...BE SURE TO TAKE ALONG YOUR CELL PHONE. WEAR A WARM COAT...GLOVES...AND BOOTS. KEEP A BLANKET... FLASHLIGHT...FOOD...AND WATER IN YOUR VEHICLE IN CASE OF AN EMERGENCY. Link to comment Share on other sites More sharing options...
tnweathernut Posted January 16, 2013 Share Posted January 16, 2013 Morristown TN NWS office is so conservative, they didn't even place the Tricities of TN under an advisory?? Virtually every model shows the deform in our area. It's hard to imagine wanting to wait till the night before the event to issue something. Waiting to issue an ADVISORY?? I am biased toward wanting snow, but IMO this level of conservativeness is just too much. I would have gone with an advisory and then you could have leaned on BOTH sides of the fence for possibly more or less snow. Now they are liable to have to issue Winter Storm Warnings tonight after 0z, where nothing is currently issued. By the time that comes out, everyone is in bed................................and this is an afternoon event the NEXT day. SMH Link to comment Share on other sites More sharing options...
bingcrosbyb Posted January 16, 2013 Share Posted January 16, 2013 Latest RPM showing convective snow showers over NE AL. Must be some incredible snowfall rates. Link to comment Share on other sites More sharing options...
packbacker Posted January 16, 2013 Share Posted January 16, 2013 Where do you access that? I can't find it for the life of me. Thanks! It's on Raleigh's model page, it's updating just a hair slower than weatherbell. 18z 4km HWRF run is sweet spot up I-85 with RDU in the 2-4" range. Link to comment Share on other sites More sharing options...
Kilgore Trout Posted January 16, 2013 Share Posted January 16, 2013 GSP official forecast for AVL is only 1-3", per their updated zone forecast. Personally, given the 18Z run of the NAM, I think this is way too conservative. Still feel 4-6" a good bet for downtown, with 8-12" likely across the Smokies and northward up the spine of the Apps. I agree that 1-3 may be conservative, but looking at the model output, the bulk of the precip is happening before the cold comes in. It looks like there is going to be a 3-6 hour window where the rain will have changed to snow from around 7 or 8 Thursday evening till midnight. The first couple of hours ought to be fun, but we are also fighting warm ground temps that will probably melt a couple of inches as well. Unless we can see that changeover earlier, or the moisture lingers longer than modeled, I think getting 6 in AVL will be hard to do. My thought right now is 3-4. Link to comment Share on other sites More sharing options...
burgertime Posted January 16, 2013 Share Posted January 16, 2013 Hi Res NAM has qpf totals going bonkers just west of CLT. 5 + inches of total QPF starting from 18z. CLT around 4 inches. Hard to tell total of snow but probably around an inch of QPF of snow? Link to comment Share on other sites More sharing options...
wncsnow Posted January 16, 2013 Share Posted January 16, 2013 Winter Storm Warning for us in the McDowell and Burke county portion of the foothills.. Also here is GSP's updated snowmap...http://www.erh.noaa.gov/gsp/stormtotal/StormTotalSnowFcst.png Link to comment Share on other sites More sharing options...
bingcrosbyb Posted January 16, 2013 Share Posted January 16, 2013 HPC, after it's discarding of the NAM earlier this week as an "outlier", folds: Link to comment Share on other sites More sharing options...
burgertime Posted January 16, 2013 Share Posted January 16, 2013 Winter Storm Warning for us in the McDowell and Burke county portion of the foothills.. Also here is GSP's updated snowmap...http://www.erh.noaa.gov/gsp/stormtotal/StormTotalSnowFcst.png Wow GSP is usually always conservative on these. Good to my my back yard (sorta) with 2.5 Link to comment Share on other sites More sharing options...
ncwinterwxman Posted January 16, 2013 Share Posted January 16, 2013 Don't quote me on this, but I ***think*** it was the GFS...however both the GFS and ECMWF generally caught on at about the same time...the GFS is slowly getting better from what it used to be...better resolution and better physics packages are coming online and so I expect its improvement to continue... Which model saw this event best and first from the longrange? Link to comment Share on other sites More sharing options...
SnowDeac Posted January 16, 2013 Share Posted January 16, 2013 Hi Res NAM has qpf totals going bonkers just west of CLT. 5 + inches of total QPF starting from 18z. CLT around 4 inches. Hard to tell total of snow but probably around an inch of QPF of snow? If we can get that level of precipitation falling to produce those QPF totals, then I would imagine the changeover would happen sooner rather than later. Either way, there is going to be some nasty black ice on Friday morning. Link to comment Share on other sites More sharing options...
burgertime Posted January 16, 2013 Share Posted January 16, 2013 One other thing that I'd be cautious about is the potential for downsloping in the escarpment just south and east of the highest elevations in the Appalachians This happens a lot with these marginal setups but any sort of adiabatic warming thanks to strong northwesterly flow off the Appalachians could put a serious damper on both precipitation and snowfall accumulations in areas that typically do very well in CAD setups. If there was a good analog to the potential outcome of this system, I'd look at the 2009 March 1-3rd southeast snowfall event in the Southeast. CIPS analog guidance is used quite frequently by the RAH office, and this particular event is actually #3 on all of the analog cases for this event in the 36 hour period. The similarities are pretty remarkable with the exception that its about 2 months later in the season. In terms of expected conditions, the March 1-3rd event had more cold air to work with, but at the same time more solar radiation that was eating away at the cold air source region. However, that particular event also highlights my concerns with descent on the lee side of the mountains, where a local minima in snowfall accumulated resulted. Now again I think this event I'm highlighting above had more cold air to work with, but the advantage with this particular system upcoming is that we are still in the middle of winter, so those that do switch over to snow are more likely to get decent accumulations in the absence of a strong sun elevation angle. In heavy wet snow situations such as this, ground temperature is more of an afterthought rather than a primary limiting factor for snowfall accumulation since heavy snowfall rates can easily overcome a warm ground temperature. Thanks Phil, I know this was asked before about why there is less in those areas. That answers that. Link to comment Share on other sites More sharing options...
Winterhawk Posted January 16, 2013 Share Posted January 16, 2013 The SPC WRF which I've found does a remarkable job on these events alot of the time supports WXSouth's idea that NRN GA could get pounded, very close to ATL as well. That would be a treat; tks for the info. Wll be interesting to see how the short-range hi-res models do with this one. Trends have been rather favorable so far.. Link to comment Share on other sites More sharing options...
Thrasher Fan Posted January 16, 2013 Share Posted January 16, 2013 Which model saw this event best and first from the longrange? I'd have to say the NAM even in its not so longrange format had this nailed from the time it entered into its range. GFS struggled with basically every aspect except the idea of a storm occuring. Never had temps or QPF accurate. Link to comment Share on other sites More sharing options...
valkhorn Posted January 16, 2013 Share Posted January 16, 2013 Any Hi Res surprises west of the mountains by chance? I'd love to see the hi res NAM output for snow in East TN - The latest I can find is the 12z. Link to comment Share on other sites More sharing options...
HurricaneTracker Posted January 16, 2013 Share Posted January 16, 2013 I agree that 1-3 may be conservative, but looking at the model output, the bulk of the precip is happening before the cold comes in. It looks like there is going to be a 3-6 hour window where the rain will have changed to snow from around 7 or 8 Thursday evening till midnight. The first couple of hours ought to be fun, but we are also fighting warm ground temps that will probably melt a couple of inches as well. Unless we can see that changeover earlier, or the moisture lingers longer than modeled, I think getting 6 in AVL will be hard to do. My thought right now is 3-4. I respectfully disagree. The bulk of the precip occurs during the transition time. Yes, the snow window is 5pm to 10pm, but with possible thundersnow and very intense upward vertical velocities ( > 24 umb/s), I expect snowfall rates to be 2-3" per hour. Subtract the first hour for melting and making slush, and then the rest of the time, 7-10pm for snow. That gives us an easy 6". This is a very dynamic system! Surface temps will be offset by the heavy snowfall rates, and "warm ground" will be quickly overtaken as well. This system is being underrated, yet all the maps I've seen suggest a really powerhouse storm. Do not underestimate the power of the ULL, mid-lapse rates, and snowfall rates! Link to comment Share on other sites More sharing options...
RaleighWx Posted January 16, 2013 Share Posted January 16, 2013 Euro Ensemble in good agreement with operational euro as far as snowfall accumulation. Link to comment Share on other sites More sharing options...
Kilgore Trout Posted January 16, 2013 Share Posted January 16, 2013 I respectfully disagree. The bulk of the precip occurs during the transition time. Yes, the snow window is 5pm to 10pm, but with possible thundersnow and very intense upward vertical velocities ( > 24 umb/s), I expect snowfall rates to be 2-3" per hour. Subtract the first hour for melting and making slush, and then the rest of the time, 7-10pm for snow. That gives us an easy 6". This is a very dynamic system! Surface temps will be offset by the heavy snowfall rates, and "warm ground" will be quickly overtaken as well. This system is being underrated, yet all the maps I've seen suggest a really powerhouse storm. Do not underestimate the power of the ULL, mid-lapse rates, and snowfall rates! Thanks for your thoughts, and I do hope you are right (you present a strong case). The key is going to be how quick that transition happens. Link to comment Share on other sites More sharing options...
valkhorn Posted January 16, 2013 Share Posted January 16, 2013 MRX just bumped up the local forecast for Knoxville to 1-3". If they're still playing it conservative, then maybe we'll get more? It's still under advisory criteria. Link to comment Share on other sites More sharing options...
tnweathernut Posted January 16, 2013 Share Posted January 16, 2013 MRX just bumped up the local forecast for Knoxville to 1-3". If they're still playing it conservative, then maybe we'll get more? It's still under advisory criteria. Updated to give KTRI an inch or less. What am I missing? Kind of comical to be honest. Link to comment Share on other sites More sharing options...
RaleighWx Posted January 16, 2013 Share Posted January 16, 2013 For those looking for 4km NAM graphics. Here is my page. I am still tweaking things so a few parameters arent plotting. But here it is: http://raleighwx.americanwx.com/models/NAM4km.html Link to comment Share on other sites More sharing options...
Recommended Posts
Archived
This topic is now archived and is closed to further replies.