Lookout Posted January 7, 2011 Share Posted January 7, 2011 The nam's simulated radar is damn impressive. It certainly seems like it has some convective elements in it, which isn't surprising considering the 700mb VV's..it brings the heart of it right over the atlanta/athens/85 corridor. Any locations caught under such a band would pick some extremely impressive snow rates in a hurry..and dropping more snow than expected. I know it's the long range nam but good lord I hope it verifies. A stripe of 1 inch amounts from atlanta to athens/85 corridor into the upstate. Link to comment Share on other sites More sharing options...
Shawn Posted January 7, 2011 Share Posted January 7, 2011 It could make sense with upper level dynamics, not a strong surface low, driving the show. Not saying this run is correct, but it is not insane. Yeah, that's a pretty good point. It looks like I was just impatient and it nails us good around hour 78 anyway. Wow @ that spot around Macon/Augusta Link to comment Share on other sites More sharing options...
Cheeznado Posted January 7, 2011 Share Posted January 7, 2011 Snow accumulation product has solid 6-9" over all of north GA- precip type maps say changeover to sleet about 15Z, Link to comment Share on other sites More sharing options...
Shawn Posted January 7, 2011 Share Posted January 7, 2011 NAM looks to maybe get 4-6" in my area of Lexington, SC. I hate these snowfall maps though! Link to comment Share on other sites More sharing options...
BullCityWx Posted January 7, 2011 Share Posted January 7, 2011 Link to comment Share on other sites More sharing options...
Rankin5150 Posted January 7, 2011 Share Posted January 7, 2011 i put it in scattered parts of this thread, but basically its dynamics aloft haven't matched the surface, what should happen, but I don't know why, other than this might be a bias or a reflection of the strong high pressure in the Ohio Valley, and the strong 50/50 confluence, which we don't have much of, so since this is a rare situation, its hard to say. We just don't get many setups like this, but when we did in the past, the precip shield just traversed right along, basically up 85 for us. However this time we've got the incoming rockies system so that is messing with the model's physics. But, once again, this is similar to the Jan 1983 system, somewhat, but not an exact setup, so who knows what really happens. I'm inclined to think the usual will occur with what happened in the past. And that blended with the dynamics and track and setup I'm seeing is that snow will stretch from northeast Texas to southern third of Arkansas and spread east/northeast from there, and I'd ad the heavies snow might be north Texas, southern Ark, to central/north Miss, and probably would include n. Alabama, n. Ga and once we get into the western Carolnas it just depends on how much lift carries east. Normally, I'd say good setup but with the models all dropping amounts suddenly here, that gives me pause. We really need more time to see the trends, and not get gung ho on the amounts yet. It could still easily be a big snowfall here, but theres never a guarantee on any one specific spot, esp right here, which might be the hardest spot in the U.S. to accurately forecast a snowstorm becuase of the extreme complex mtn. interactions we have. Just looking at the rest of the 18z run, it appears its a good bit wetter here , with a general look of the JMA and SREF ensembles, on the precip shield orientation. I noticed it held the 5H vort together stronger clear through Tennessee and northern GA. But its an off run of NAM, obviously we'll be watching the 00z closely. Nothing is certain, good or bad , here. Thanks for putting this all into one post Robert. It helps me understand to where I can maybe chime in on a model run down the road. Thanks again! I appreciate the Mods allowing us to learn and the Met's providing the time to explain! Link to comment Share on other sites More sharing options...
FoothillsNC Posted January 7, 2011 Share Posted January 7, 2011 Huge hit all areas just to my southwest. Even here its around .60" I'm guessing but havent' studied the exact qpf, just the trends. The orientation looks realistic, and no doubt this is major snow in n. Ga and Ala, Miss, where the moisture and cold are maximized. The folks just south of the heart of the snow area will have a massive sleet storm and a few spots of ZR somewhere in central Ga back west to central MS. Link to comment Share on other sites More sharing options...
Cheeznado Posted January 7, 2011 Share Posted January 7, 2011 I think these NAM snow depth products include at least sleet and maybe even ZR- that has too much "snow" in central GA Link to comment Share on other sites More sharing options...
SN_Lover Posted January 7, 2011 Share Posted January 7, 2011 Here is a previous time frame with the same model. Very impressive! Link to comment Share on other sites More sharing options...
burgertime Posted January 7, 2011 Share Posted January 7, 2011 Huge hit all areas just to my southwest. Even here its around .60" I'm guessing but havent' studied the exact qpf, just the trends. The orientation looks realistic, and no doubt this is major snow in n. Ga and Ala, Miss, where the moisture and cold are maximized. The folks just south of the heart of the snow area will have a massive sleet storm and a few spots of ZR somewhere in central Ga back west to central MS. I love what the NAM was showing in the overall setup. I really feel like Matt and Brandon that this thing is going to come down to almost a nowcast situation. For the folks on the wrong side of that cutoff....boy what a heartbreaker. Link to comment Share on other sites More sharing options...
RevDodd Posted January 7, 2011 Share Posted January 7, 2011 Per the NAM soundings, a good bit of that wedge of precip into central NC could be sleet or FRZ. Link to comment Share on other sites More sharing options...
Lookout Posted January 7, 2011 Share Posted January 7, 2011 Huge hit all areas just to my southwest. Even here its around .60" I'm guessing but havent' studied the exact qpf, just the trends. The orientation looks realistic, and no doubt this is major snow in n. Ga and Ala, Miss, where the moisture and cold are maximized. The folks just south of the heart of the snow area will have a massive sleet storm and a few spots of ZR somewhere in central Ga back west to central MS. Looking closely it would appear I would get 1 inch liquid, ALL snow..before getting some light sleet/freezing rain/drizzle. I sure hope the other models agree but I'm interesting in the idea of convective elements and thundersnow within some of this which would really make things impressive. Link to comment Share on other sites More sharing options...
burgertime Posted January 7, 2011 Share Posted January 7, 2011 I think these NAM snow depth products include at least sleet and maybe even ZR- that has too much "snow" in central GA I believe the SV maps account for ZR and sleet, they have the northern half of GA in 4-8 with a small area NW of ATL in 8-12...for us in WNC it's just 2-4 except around GSP and directly north it's 4-8 Link to comment Share on other sites More sharing options...
CaryWx Posted January 7, 2011 Share Posted January 7, 2011 Can't say I like central NC chances based on RAH. Sounds like a second stronger low will be west of the apps and the weaker one to move out of the GOM and offshore in the Atlantic. This will hurt the ability to get good cold (snowy) air into our region. AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE RALEIGH NC 316 PM EST FRI JAN 7 2011 ...CONCERNING THE POTENTIAL WINTER SYSTEM TO AFFECT REGION MONDAY AND TUESDAY...DISTURBANCES IN THE SPLIT FLOW OVER THE WEST COAST HAVE JUST TODAY BECOME WELL SAMPLED AS THEY MOVE INTO THE DESERT SOUTHWEST AND PACIFIC NORTHEAST RESPECTIVELY. MODELS CONTINUE TO INDICATE THE SOUTHERN STREAM WAVE WILL EJECT EASTWARD AND DEAMPLIFY AS IT CROSSES THE MID-MISSISSIPPI VALLEY REGION ON SUNDAY. ON ITS HEELS...THE NORTHERN STREAM WAVE WILL DIG SOUTH THROUGH THE ROCKIES THROUGH MONDAY. THERE HAS BEEN A TREND TO DEAMPLIFY THE SOUTHERN WAVE MORE AND PULL IT NORTH THROUGH THE TENN VALLEY...WHICH LEADS TO A WEAKER SURFACE LOW ALONG THE GULF COAST AND A SECONDARY WAVE WEST OF THE MOUNTAINS. GOOD AGREEMENT AT 84HRS (MONDAY EVENING) OF A LOW CROSSING FLORIDA AND MOVING UP THE CAROLINA COAST MONDAY NIGHT AND TUESDAY....WITH MOISTURE SURGING ACROSS THE AREA SOUTHWEST TO NORTHEAST MIDDAY MONDAY THROUGH TUESDAY MORNING...EXITING TO THE NE DURING THE DAY TUESDAY. CONCERNING PTYPES...QUITE A BIT OF UNCERTAINTY REMAINS...BUT A WEAK COASTAL LOW...LACK OF A TRUE HIGH PRESSURE TO THE NORTH...AND A SECONDARY SURFACE LOW AND H85 LOW WEST OF THE MOUNTAINS SUPPORTS A MORE MIXED PTYPE EVENT. SINCE THE LEAD SHORTWAVE IS FORECAST TO BE DEAMPLIFIED AND THE BEST HEIGHT FALLS WITH THE NORTHERN WAVE ARE PROGGED TO OCCUR OVER THE OHIO VALLEY..PRECIP AMOUNTS LOOK TO BE MAINLY DRIVEN BY MODEST WARM ADVECTION FROM THE SOUTHEAST. THIS ALSO ARGUES FOR A TRANSITION FROM SNOW AT ONSET TO A PTYPE MIX LATE MONDAY THROUGH TUESDAY MORNING (SNOW NW AND RAIN SE)...FITTING CLIMATOLOGY QUITE WELL. GFS/ECMWF CRITICAL THICKNESS NOMOGRAMS SUPPORT THIS THINKING ALSO...SO THE CURRENT FORECAST REFLECTS MORE IN THE WAY OF A MIX FOR A LARGER PORTION OF THE CWA TO THE SOUTHEAST OF THE TRIAD. TEMPS STARTING MONDAY MORNING WILL BE LARGELY INFLUENCED BY THE TIMING OF PRECIP ONSET...BUT GIVEN A COLD START WILL LIKELY HAVE A HARD TIME SURPASSING THE MID 30S...MAYBE UPPER 30S WHERE PRECIP HOLDS OFF LONGEST.-- End Changed Discussion -- Link to comment Share on other sites More sharing options...
MichaelJ Posted January 7, 2011 Share Posted January 7, 2011 Looking at the comparison graphic the precip field has definitely come North a good bit Link to comment Share on other sites More sharing options...
Wow Posted January 7, 2011 Share Posted January 7, 2011 Sounding for CLT... All snow - 5.2" QPF: 0.48" Sfc temps in the mid 20s throughout Ratio 10 to 15:1 Link to comment Share on other sites More sharing options...
BullCityWx Posted January 7, 2011 Share Posted January 7, 2011 Sounding for CLT... All snow - 5.2" QPF: 0.48" yep, seems to be all snow until 84 where it's probably sleet or freezing drizzle, depending on how much moisture is left and where it's at in the atmosphere. The NAM is a nudge north with the QPF from having a major event here. Link to comment Share on other sites More sharing options...
burgertime Posted January 7, 2011 Share Posted January 7, 2011 Sounding for CLT... All snow - 5.2" QPF: 0.48" Sfc temps in the mid 20s throughout Ratio 10 to 15:1 I'll take it with the optimism that more moisture comes in. Would be great if we get the higher end of the ratios. Link to comment Share on other sites More sharing options...
HKY_WX Posted January 7, 2011 Share Posted January 7, 2011 updated http://www.examiner.com/weather-in-charlotte/current-thoughts-on-coming-winter-storm Link to comment Share on other sites More sharing options...
Rankin5150 Posted January 7, 2011 Share Posted January 7, 2011 yep, seems to be all snow until 84 where it's probably sleet or freezing drizzle, depending on how much moisture is left and where it's at in the atmosphere. The NAM is a nudge north with the QPF from having a major event here. Based on past storms, the odds of MORE QPF are still in our favor Jerms and JohnWow. We just have to wait and see I guess... Link to comment Share on other sites More sharing options...
FoothillsNC Posted January 7, 2011 Share Posted January 7, 2011 I hate to read too much into an 18z run, but it maintains the upper support 6 hours longer (think the models have been doing that for a few runs now) and the VV are excellent along its path, and between it and the surface low, but mainly underneath the comma head crossing Alabama, central and northern Georgia and into the western Carolinas, then it weakens on the last panel. The trend is probably what matters. Snow rates would get heavy quickly in N. Ga especially, meaning Atlanta and points north really around 20, north, because the air is so cold aloft and the surface is probably mid 20's, maybe even lower 20's in northeast GA early Monday morning, with heavy snow and strong northeast winds...Perfect damming from a 1032 high over the Ohio Valley. I guess only time will tell if the vort holds stronger, we really don't need a good surface low, the moisture is mostly going to come from the good overrunning well north of the surface low and the divergence associated with 5H feature., atleast for the western Carolinas Link to comment Share on other sites More sharing options...
tgarren Posted January 7, 2011 Share Posted January 7, 2011 based on what i have seen i am not that excited for our chances in the more central and eastern areas of nc. what the models seem to all agree on is there will be a storm, it will blow up in the gulf and then it will weaken as it moves north and west. its possible that it maeks it up this way but any model you look at its making its way up here as a weakening system, not one that is strengthening. that worries me for moisture as well as temps and the models show both these fears. maybe the next few runs will change but given what i see i just don't have high hopes for my area. i do hope it slams the guys in GA though. hope to be reading plenty of obs posts with you guys going crazy! Link to comment Share on other sites More sharing options...
Wild Weather Monger Posted January 7, 2011 Share Posted January 7, 2011 ATL 1.02 75% snow AHN 1.03 90% snow PDK 1.02 90% snow MCN 1.19 50/50 snow/zr...ouch BHM 1.06 90% snow Surface temps well below freezing. Occurs at night. Historic storm for the deep south verbatim. Link to comment Share on other sites More sharing options...
CaryWx Posted January 7, 2011 Share Posted January 7, 2011 Brandon, that "surface reflection" you speak of in your write-up is what makes me believe will actually weaken the s/w over the GOM and possibley rob a good portion of NC from deep enough (solid) CAD for predominent snow. Basically what RAH is "currently" suggesting. Does that sound plausible? Link to comment Share on other sites More sharing options...
beanskip Posted January 7, 2011 Share Posted January 7, 2011 Atlanta - 6-8 inches of snow with .25 inch of ice on top? OUCH! ATL 1.02 75% snow AHN 1.03 90% snow PDK 1.02 90% snow MCN 1.19 50/50 snow/zr...ouch BHM 1.06 90% snow Surface temps well below freezing. Occurs at night. Historic storm for the deep south verbatim. Link to comment Share on other sites More sharing options...
Stormsfury Posted January 7, 2011 Share Posted January 7, 2011 Looking closely it would appear I would get 1 inch liquid, ALL snow..before getting some light sleet/freezing rain/drizzle. I sure hope the other models agree but I'm interesting in the idea of convective elements and thundersnow within some of this which would really make things impressive. There are. Earlier soundings had KMCN with thundersleet at hour 81 I believe on the 12z NAM run Link to comment Share on other sites More sharing options...
rosie Posted January 7, 2011 Share Posted January 7, 2011 I think these NAM snow depth products include at least sleet and maybe even ZR- that has too much "snow" in central GA Am I seeing right, a foot in this area? Link to comment Share on other sites More sharing options...
MichaelJ Posted January 7, 2011 Share Posted January 7, 2011 Good disco Brandon and it makes a lot of sense. If that surface reflection gets too strong however, then it would definitely rob moisture from the s/w coming up from the South. Link to comment Share on other sites More sharing options...
SnowNiner Posted January 7, 2011 Share Posted January 7, 2011 Thanks! The southern stream shortwave is getting properly sampled over the next several model cycles, although keep in mind that the models ingests a lot of data from aircraft soundings as well.. so its likely getting a pretty good sample currently with the ULL being near LAX. Yeah I'm starting to think this s/w is what it is....to borrow from the John Fox vocabulary. Looking at the water vapor loop, it doesn't look as impressive as the Christmas storm when it was spinning out in the pacific. Plus I'm not hearing any news stories about California getting hammered by a storm. I think this wave just isn't very strong and the models are picking up on that. Well see what the models say tomorrow. I think that tells the tale. Link to comment Share on other sites More sharing options...
RaleighWx Posted January 7, 2011 Share Posted January 7, 2011 My afternoon update. http://www.examiner.com/weather-in-raleigh/some-light-snow-possible-tonight-with-another-southeast-winter-storm-later Link to comment Share on other sites More sharing options...
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