DaculaWeather Posted January 23, 2013 Share Posted January 23, 2013 Watch the CAD at about 40 hours, cold air comes pouring south. http://www.daculaweather.com/4_sref_09_2m_nws_loop.php Link to comment Share on other sites More sharing options...
FallsLake Posted January 23, 2013 Share Posted January 23, 2013 For locations that do get snow would the ratioes be higher? Not sure if upper air temps determine this or near surface (or both). Link to comment Share on other sites More sharing options...
Buddy1987 Posted January 23, 2013 Share Posted January 23, 2013 Can anyone see what the HP is up north? Wondering if it weakened at all to let the "trend" start when the low creeps a little more north as we get closer to the event. Would love for everyone to all have a 1/2 in QPF and stay below freezing throughout Link to comment Share on other sites More sharing options...
Brick Tamland Posted January 23, 2013 Share Posted January 23, 2013 I thought the other models were actually better than previous runs of the NAM. This run looks like things are trending better. Link to comment Share on other sites More sharing options...
Buddy1987 Posted January 23, 2013 Share Posted January 23, 2013 Watch the CAD at about 40 hours, cold air comes pouring south. http://www.daculaweather.com/4_sref_09_2m_nws_loop.php That is very impressive even drives the 32 line all the way to my parents in Charleston SC Link to comment Share on other sites More sharing options...
DaculaWeather Posted January 23, 2013 Share Posted January 23, 2013 Steve, please a brief education for me ... Thickness is, cloud coverage? depth of precip? Thanks still learning, Kat The thickness is the distance between those two levels. As it gets colder, that thickness decreases as the cold air is more dense. As the thickness gets lower, the chance for winter precip goes up. The P-type nomograms depict the thickness and displays the precip type based on that thickness. On the nomograms I have, if you scroll down below the first graph, there is another graph, if you hover over each section, it describes in more detail what happens if precip falls into those thicknesses. Link to comment Share on other sites More sharing options...
Tyler Penland Posted January 23, 2013 Share Posted January 23, 2013 Anybody know what's up with the hole over NE GA on FFC's map? lol Sent from my Nexus One using Tapatalk 2 Don't see a hole but if you're talking about the white area... guess what that is! What is it lol. Usually their graphicasts are pretty self explanatory. I know it isn't rain and sleet don't make sense. Not a precip hole either. Sent from my Nexus One using Tapatalk 2 Link to comment Share on other sites More sharing options...
Buddy1987 Posted January 23, 2013 Share Posted January 23, 2013 Simulated radar at 54 looks nice for most of us as well Link to comment Share on other sites More sharing options...
MotoWeatherman Posted January 23, 2013 Share Posted January 23, 2013 It's gonna be interesting watching the rest of the 12z runs come in. NAM at 1pm Friday has my sfc temp at 27 which spells a very nice freezing rain event. Soundings no longer show any potential for a brief column wetbulb below freezing so this would likely be a sleet to freezing rain type of deal. Link to comment Share on other sites More sharing options...
RaleighWx Posted January 23, 2013 Share Posted January 23, 2013 here is the 12z 4km NAM snow forecast for 60 hours http://raleighwx.americanwx.com/models/nam4km/12znamsnowSE060.gif Link to comment Share on other sites More sharing options...
MotoWeatherman Posted January 23, 2013 Share Posted January 23, 2013 Anybody know what's up with the hole over NE GA on FFC's map? lol Sent from my Nexus One using Tapatalk 2 It means you and I are screwed. LOL. Personally I don't think it makes any sense. Link to comment Share on other sites More sharing options...
franklin NCwx Posted January 23, 2013 Share Posted January 23, 2013 It's gonna be interesting watching the rest of the 12z runs come in. NAM at 1pm Friday has my sfc temp at 27 which spells a very nice freezing rain event. Soundings no longer show any potential for a brief column wetbulb below freezing so this would likely be a sleet to freezing rain type of deal.seems to be more waa in the midlevel. But that also brings in more qpf Link to comment Share on other sites More sharing options...
DixieBlizzard Posted January 23, 2013 Share Posted January 23, 2013 For North Georgia folks, is there any similarity between this storm and the mini ice storm of December 2010. That one had minimal precipitation but cold temps and cold ground made it a driving nightmare. What a nightmare for so little freezing rain! Cheston, if it were my guess, this actually reminds me a little more of January 2000, especially if there is more than .25 of ice accretion. This one might be a little nasty. Link to comment Share on other sites More sharing options...
Brick Tamland Posted January 23, 2013 Share Posted January 23, 2013 here is the 12z 4km NAM snow forecast for 60 hours http://raleighwx.americanwx.com/models/nam4km/12znamsnowSE060.gif Mix a couple of inches of snow with sleet and freezing rain and it's going to be major trouble on the roads. Link to comment Share on other sites More sharing options...
MotoWeatherman Posted January 23, 2013 Share Posted January 23, 2013 here is the 12z 4km NAM snow forecast for 60 hours http://raleighwx.americanwx.com/models/nam4km/12znamsnowSE060.gif How is that derived when soundings for even my back yard in far NE GA pretty much show freezing rain? Link to comment Share on other sites More sharing options...
beanskip Posted January 23, 2013 Share Posted January 23, 2013 Hard to have much confidence in these maps with the NAM's own sounding show almost all IP/ZR in I-85 corridor where this shows 2-4 inches of snow. here is the 12z 4km NAM snow forecast for 60 hours http://raleighwx.americanwx.com/models/nam4km/12znamsnowSE060.gif Link to comment Share on other sites More sharing options...
RaleighWx Posted January 23, 2013 Share Posted January 23, 2013 How is that derived when soundings for even my back yard in far NE GA pretty much show freezing rain? The run a post-processing algorithm that is applied to the model using certain parameters like temperatures/thicknesses at certain levels, wet-bulb temperatures, etc. YOu always use literal model snow forecasts with a grain of salt. Link to comment Share on other sites More sharing options...
MotoWeatherman Posted January 23, 2013 Share Posted January 23, 2013 seems to be more waa in the midlevel. But that also brings in more qpf Yep. But I will take that if we can get more QPF. This is pretty much an ice type of deal for us so as long as the CAD holds then let the WAA increase above the surface. Link to comment Share on other sites More sharing options...
SnowGoose69 Posted January 23, 2013 Share Posted January 23, 2013 The 12Z Canadian RGEM is similar idea to the NAM through 48... Link to comment Share on other sites More sharing options...
superjames1992 Posted January 23, 2013 Share Posted January 23, 2013 How good is the high-resolution NAM typically at (presumably) longer hours (48+)? I don't think I've really used that model much. Link to comment Share on other sites More sharing options...
MotoWeatherman Posted January 23, 2013 Share Posted January 23, 2013 The run a post-processing algorithm that is applied to the model using certain parameters like temperatures/thicknesses at certain levels, wet-bulb temperatures, etc. YOu always use literal model snow forecasts with a grain of salt. Of course. It's just that usually the maps line up a little better with sounding P-Types so that's why i asked. Link to comment Share on other sites More sharing options...
RaleighWx Posted January 23, 2013 Share Posted January 23, 2013 Of course. It's just that usually the maps line up a little better with sounding P-Types so that's why i asked. Sure yeah it is a complicated process. Typically it seems the NAM snow-forecasts are a bit overdone. Link to comment Share on other sites More sharing options...
NCSNOW Posted January 23, 2013 Share Posted January 23, 2013 Nam matches Euro from 0z very well. Only one model out there spilling the the dry bone Nada forecast still (GFS). Time for it to get on board. Link to comment Share on other sites More sharing options...
beanskip Posted January 23, 2013 Share Posted January 23, 2013 And it's QPF, and it's cold air avection, and ...... Sure yeah it is a complicated process. Typically it seems the NAM snow-forecasts are a bit overdone. Link to comment Share on other sites More sharing options...
RaleighWx Posted January 23, 2013 Share Posted January 23, 2013 BUFKIT soundings for the NAM soundings for RDU show 0.35 inches or so at RDU airport. Looks like the first 0.25 should be all snow, with the last 0.1 a snow/sleet mix. Taken literally. Link to comment Share on other sites More sharing options...
Wow Posted January 23, 2013 Share Posted January 23, 2013 Would be nice to see the nam gain support from other models. It can be used in conjunction with them, but alone it is virtuallly useless this far out IMO. If the euro/gfs/ggem can come in with a higher QPF output, it could be time to get excited for something more than a nuisance event. We shall see. The EE rule still applies! Link to comment Share on other sites More sharing options...
beanskip Posted January 23, 2013 Share Posted January 23, 2013 EE + WEEKEND RULE = WOOF! The EE rule still applies! Link to comment Share on other sites More sharing options...
calculus1 Posted January 23, 2013 Share Posted January 23, 2013 Soundings at Hickory seem to indicate start as snow then go to sleet. With the melting layer at 700/800 mb, there's still a lot of cold air to fall through below that with temps ranging from -4 to -8 C. I would assume then it would be able to refreeze before hitting the ground. Thus, sleet as opposed to freezing rain. Link to comment Share on other sites More sharing options...
EmersonGA Posted January 23, 2013 Share Posted January 23, 2013 What a nightmare for so little freezing rain! Cheston, if it were my guess, this actually reminds me a little more of January 2000, especially if there is more than .25 of ice accretion. This one might be a little nasty. I would take January 2000 over 2010 in a heartbeat. That one was beautiful and we didn't lose power. Link to comment Share on other sites More sharing options...
eyewall Posted January 23, 2013 Share Posted January 23, 2013 GFS is rolling. Link to comment Share on other sites More sharing options...
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