nrgjeff Posted November 25, 2013 Share Posted November 25, 2013 Edit: Just saw the ice storm warning. Heavy rain and local flooding may steal some headlines. Any strong storms near the coast may be after dark. Back to winter, this will be more in-situ than classic wedge for western NC tonight/Tue morning. Northeast Georgia is more conditional with warmer temps at the moment. Lack of a good high is becoming less of an issue for NC with clouds hampering warming today and dews staying quite low. Sometimes ice just happens. Due to high QPF icing could should surprise esp high valleys. East facing slopes are a bigger concern than west facing slopes with good WAA. Hope east slopes get WAA too, if one likes heat and light for Thanksgiving. Then Tuesday evening thru Wednesday morning East Tennessee will play the snow game. Agree western NC shadows are hosed this event. However 12Z guidance perked up (again, zig zag, lol) for Northeast Tenn. Chattanooga will probably crap out. When unsure and/or 50/50 line is over CHA go rain. In contrast Tri Cities get snow in the same situation, but I think they have a much better than 50/50 shot at a couple inches of snow this time. Knoxville really is 50/50 with zig zag guidance; yes, 12Z says a dusting in Knox. Upper Cumberland Plateau in TN should get an inch or two, with Smokies picking up 6"+ at elevation. Ski areas should get some natural help Wednesday. Cheers! Link to comment Share on other sites More sharing options...
avianman Posted November 25, 2013 Share Posted November 25, 2013 That hole in the middle of Catawba County seems odd to me. Here's the current thinking of GSP with regards to ice accretion overnight: This is probably why they made the Ice Storm Warning call. Link to comment Share on other sites More sharing options...
calculus1 Posted November 25, 2013 Share Posted November 25, 2013 That hole in the middle of Catawba County seems odd to me. I agree. I had the same thoughts. Perhaps it's Lake Hickory effect warmth? Or urban heat island effect of the Hickory metroplex? Link to comment Share on other sites More sharing options...
nchighcountrywx Posted November 25, 2013 Share Posted November 25, 2013 Major Temperature Gradient Across North Carolina Forecast by NAM WRF for 1000pm Tuesday evening 26NOV13 A North Carolina Classic: Snow and Ice Storm in the Mountains 70 Degrees down east Image Courtesy of WeatherBell and Dr Ryan Maue Link to comment Share on other sites More sharing options...
avianman Posted November 25, 2013 Share Posted November 25, 2013 Lake Hickory isn't big enough for that. Lake James is 3 times the size and has no effect on the temps. I'm assuming they get these maps from model data. Do models take cities into account? I doubt they do. Very odd. I know. Perhaps it's Lake Hickory effect warmth? Or urban heat island effect of the Hickory metroplex? Link to comment Share on other sites More sharing options...
superjames1992 Posted November 25, 2013 Share Posted November 25, 2013 Wow, that's quite the gradient, as progged. 37F IMBY and over 60F in southeastern Guilford County just ~20 miles to the east. That would be impressive if it verifies. Link to comment Share on other sites More sharing options...
BullCityWx Posted November 25, 2013 Share Posted November 25, 2013 Well, the euro has come in colder at the surface. If it's to be believed, there could be a surprise significant ice storm across much of the western piedmont/foothills of NC. Link to comment Share on other sites More sharing options...
HurricaneTracker Posted November 25, 2013 Share Posted November 25, 2013 Well, the euro has come in colder at the surface. If it's to be believed, there could be a surprise significant ice storm across much of the western piedmont/foothills of NC. How much colder? How long does the ZR event last? Link to comment Share on other sites More sharing options...
DopplerWx Posted November 25, 2013 Share Posted November 25, 2013 Well, the euro has come in colder at the surface. If it's to be believed, there could be a surprise significant ice storm across much of the western piedmont/foothills of NC. yikes, euro puts some sig ice down for western nc. Link to comment Share on other sites More sharing options...
BullCityWx Posted November 25, 2013 Share Posted November 25, 2013 How much colder? How long does the ZR event last? Only 1 degree but it's the degree that matters. It looks like anywhere from .2 to .4 of ZR falls along 74 west of Charlotte up to I-40. The model doesnt look like it brings us above freezing until some time after 8AM. Link to comment Share on other sites More sharing options...
1300m Posted November 25, 2013 Share Posted November 25, 2013 Just a general statement on freezing rain but in my opinion/experience freezing rain with a temperature at or above 30F is typically a self-limiting process because the latent heat of freezing results in melting and warming of the near-surface layer, limiting ice accrual. Rarely have I ever seen a significant icing event occur when the surface temp wasn't colder than 30F during the event, although granted the antecedent cold conditions are helping to keep the ground (and other surfaces) cold before this one. Link to comment Share on other sites More sharing options...
GaWx Posted November 25, 2013 Share Posted November 25, 2013 Just a general statement on freezing rain but in my opinion/experience freezing rain with a temperature at or above 30F is typically a self-limiting process because the latent heat of freezing results in melting and warming of the near-surface layer, limiting ice accrual. Rarely have I ever seen a significant icing event occur when the surface temp wasn't colder than 30F during the event, although granted the antecedent cold conditions are helping to keep the ground (and other surfaces) cold before this one. Atlanta has had a good number of major and lengthy ZR's with the lowest near or even slightly above 30. I've researched numerous old icestorms in the area. It certainly isn't rare in this area though it may be in your area. Link to comment Share on other sites More sharing options...
tarheelwx Posted November 25, 2013 Share Posted November 25, 2013 My experience is that if the temp is 31 or 32 and the rain is moderate to heavy, it is very difficult for it to freeze. So my thinking is that this will be close, but not major. TW Link to comment Share on other sites More sharing options...
BullCityWx Posted November 25, 2013 Share Posted November 25, 2013 Just a general statement on freezing rain but in my opinion/experience freezing rain with a temperature at or above 30F is typically a self-limiting process because the latent heat of freezing results in melting and warming of the near-surface layer, limiting ice accrual. Rarely have I ever seen a significant icing event occur when the surface temp wasn't colder than 30F during the event, although granted the antecedent cold conditions are helping to keep the ground (and other surfaces) cold before this one. While I totally agree with you about it being an eventual self limiting process, I do want to mention the December 2005 event which was almost totally in-situ driven. You can see from the obs that it was about an 6 hour event but it was still a fairly damaging ice storm well into SC. http://www.wunderground.com/history/airport/KCLT/2005/12/15/DailyHistory.html Link to comment Share on other sites More sharing options...
1300m Posted November 25, 2013 Share Posted November 25, 2013 Atlanta has had a good number of major and lengthy ZR's with the lowest near or even slightly above 30. I've researched numerous old icestorms in the area. I'm referring to significant impacts with icy roads, downed trees, power outages and whatnot, rather than freezing rain by name only. I really find it hard to believe that you could get significant ice accrual with the surface temperature at only 31 or 32 degrees. I've never seen it myself. Also keep in mind that airport observations may not represent local effects, so just because ATL is reporting 32F doesn't mean that in the suburbs that's what the temperature actually is. This page also explains it pretty well: http://www.theweatherprediction.com/habyhints/210/ Link to comment Share on other sites More sharing options...
HKY18 Posted November 25, 2013 Share Posted November 25, 2013 I've noticed that trying to pinpoint exact location for damaging ice accural can be difficult. Literally have witnessed 1 to 2 miles being the difference between damaging ice to no ice whatsoever. Really think they're will be some surprises given how borderline the situation is. Link to comment Share on other sites More sharing options...
Thrasher Fan Posted November 25, 2013 Share Posted November 25, 2013 Quick question... Are there any good sites for observing wet bulb temps? Link to comment Share on other sites More sharing options...
drfranklin Posted November 25, 2013 Share Posted November 25, 2013 While I totally agree with you about it being an eventual self limiting process, I do want to mention the December 2005 event which was almost totally in-situ driven. You can see from the obs that it was about an 6 hour event but it was still a fairly damaging ice storm well into SC. Yikes, please don't remind me of the 2005 Ice Storm - devasting around here: Case Study from GSP After the ice storm, the City of Greenville, along with Duke Power, began sponsoring a residential line conversion/"Weather the Storm" - my overhead lines are now buried...for free (paid with grants from the City of Greenville/Duke Power). Link to comment Share on other sites More sharing options...
BullCityWx Posted November 25, 2013 Share Posted November 25, 2013 Yikes, please don't remind me of the 2005 Ice Storm - devasting around here: Case Study from GSP After the ice storm, the City of Greenville, along with Duke Power, began sponsoring a residential line conversion/"Weather the Storm" - my overhead lines are now buried...for free (paid with grants from the City of Greenville/Duke Power). Also known as the Larry Cosgrove "I hope you get an inch of ice" storm from the old board. I remember that hit GSP hard. Link to comment Share on other sites More sharing options...
BullCityWx Posted November 25, 2013 Share Posted November 25, 2013 I'm also afraid that with the air so incredibly dry, we're going to see temps wet bulb a degree or two colder than forecasted. The canadian holds onto ZR for most of the piedmont until 18z tomorrow. There's no way that happens but it's definitely something interesting to look at. Link to comment Share on other sites More sharing options...
1300m Posted November 25, 2013 Share Posted November 25, 2013 Quick question... Are there any good sites for observing wet bulb temps? Just choose Wet Bulb temperature from the drop down. http://nc-climate.ncsu.edu/map/ Link to comment Share on other sites More sharing options...
POWERSTROKE Posted November 25, 2013 Share Posted November 25, 2013 our local forecast was for 40, it reached 37 before clouds covered sun? Link to comment Share on other sites More sharing options...
strongwxnc Posted November 25, 2013 Author Share Posted November 25, 2013 And we have the 1st mention of the Cosgrove event.. Well played sir.. Also known as the Larry Cosgrove "I hope you get an inch of ice" storm from the old board. I remember that hit GSP hard. Link to comment Share on other sites More sharing options...
Thrasher Fan Posted November 25, 2013 Share Posted November 25, 2013 Just choose Wet Bulb temperature from the drop down. http://nc-climate.ncsu.edu/map/ Thanks! Link to comment Share on other sites More sharing options...
griteater Posted November 25, 2013 Share Posted November 25, 2013 Just choose Wet Bulb temperature from the drop down. http://nc-climate.ncsu.edu/map/ Nice map, you can also get sfc wet-bulb contours on the SPC Mesoscale Analysis Page under Winter Weather > Sfc Wet-Bulb Temp - http://www.spc.noaa.gov/exper/mesoanalysis/new/viewsector.php?sector=17# Link to comment Share on other sites More sharing options...
superjames1992 Posted November 25, 2013 Share Posted November 25, 2013 Could the higher resolution of the Euro and recently upgraded (last winter) GGEM be allowing them to sniff out the low-level in situ CAD more skillfully? If there is a decent ice storm in the Piedmont or foothills of NC/SC/GA, that would be a pretty big win for the GGEM, which has been harping on that for a few days. RAH now has light freezing rain accumulations in my forecast, so I'd have to think they'll be throwing out Winter Weather Advisories (or Freezing Rain Advisories?) later this afternoon for the western half of their forecast zone. Link to comment Share on other sites More sharing options...
Steven_1974 Posted November 25, 2013 Share Posted November 25, 2013 Were you around the center NC area I think back in 02 or 03? Don't remind me of that. It was awful. All I remember was hearing pine tress snap all night from the weight of the ice. Wondering if any around my house were going to drop on the house. Link to comment Share on other sites More sharing options...
Shawn Posted November 25, 2013 Share Posted November 25, 2013 Aside from subtle changes even 4 or so days ago.. I think the Canadian is gonna swing one out of the park this go around. It's amazing how consistent it's been with the precip type in the Upsate/Mountains etc. Link to comment Share on other sites More sharing options...
1300m Posted November 25, 2013 Share Posted November 25, 2013 Were you around the center NC area I think back in 02 or 03? I was, that one started out with temperatures in the 20s for most of the Piedmont to around 30 at FAY, which is when most of the major ice accrual occurred. GSO obs RDU obs FAY obs Link to comment Share on other sites More sharing options...
DaculaWeather Posted November 25, 2013 Share Posted November 25, 2013 Brand new Atlanta NWS video: http://www.daculaweather.com/4_nws_videos.php Link to comment Share on other sites More sharing options...
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