SnowGoose69 Posted February 25, 2015 Share Posted February 25, 2015 The Euro clown snow maps are very low resolution and tend to spread or bleed the snow qpf contours outward on every side- so it gives the illusion of more snow down to south of I-20 but looking at the 2M temps and 850 temps they suggest not as much snow further south than what the accumulation maps show- and this also flies in the face of most of the other guidance. Also there is no evidence that the Doc is any better than the more hi-res models at this time frame History would suggest even the RGEM's snow gradient is hogwash in ATL, but I guess there are first times for everything, I dug and dug and dug today and as far as I can tell, what I was told is true, no big snowfall gradient involving a gulf low has ever occurred over Metro ATL, it HAS occurred in the case of a closed upper low, but not in this scenario. Gulf Lows usually see a gradient setup somewhere between MCN/FFC up through downtown in the case of a farther south track or in the case of a farther north track or stale airmass between RYY and the TN border. That would lead you to believe the latter occurs tomorrow, if the former occurs, well...then that was some seriously bad model forecasts. Link to comment Share on other sites More sharing options...
skbl17 Posted February 25, 2015 Share Posted February 25, 2015 At first glance, the 0z Euro looked a tad bit better for I-20 amount-wise. Probably not by enough to matter, but an improvement nonetheless. Link to comment Share on other sites More sharing options...
Cheeznado Posted February 25, 2015 Share Posted February 25, 2015 History would suggest even the RGEM's snow gradient is hogwash in ATL, but I guess there are first times for everything, I dug and dug and dug today and as far as I can tell, what I was told is true, no big snowfall gradient involving a gulf low has ever occurred over Metro ATL, it HAS occurred in the case of a closed upper low, but not in this scenario. Gulf Lows usually see a gradient setup somewhere between MCN/FFC up through downtown in the case of a farther south track or in the case of a farther north track or stale airmass between RYY and the TN border. That would lead you to believe the latter occurs tomorrow, if the former occurs, well...then that was some seriously bad model forecasts. Good post. I believe for this case the latter scenario which has occurred many times in the past- a lot of snow from somewhere near Marietta north- little south of there. Link to comment Share on other sites More sharing options...
skbl17 Posted February 25, 2015 Share Posted February 25, 2015 FFC's gone ahead and issued a freezing fog advisory for much of north Georgia...I don't think I've ever been under one of those before. Link to comment Share on other sites More sharing options...
superjames1992 Posted February 25, 2015 Share Posted February 25, 2015 21z SREF Plumes for select areas: AVL: 7.44" EMV: 6.91" GSO: 6.60" MWK: 6.02" GSP: 5.66" CLT: 5.34" ROA: 4.90" RDU: 4.65" Look up your own plumes here: http://www.spc.noaa.gov/exper/sref/fplumes/ Updated 03z SREF plumes: AVL: 7.39" EMV: 8.35" GSO: 7.59" MWK: 5.87" GSP: 5.22" CLT: 5.72" ROA: 4.56" RDU: 6.63" HSV: 5.82" BHM: 1.61" ATL: 1.01" Link to comment Share on other sites More sharing options...
jacobr57 Posted February 25, 2015 Share Posted February 25, 2015 Updated 03z SREF plumes: AVL: 7.39" EMV: 8.35" GSO: 7.59" MWK: 5.87" GSP: 5.22" CLT: 5.72" ROA: 4.56" RDU: 6.63" I have 8.09 as the mean of AVL? Maybe just checked the wrong plume or something. Regardless they're quite skewed due to the ARW family. Link to comment Share on other sites More sharing options...
superjames1992 Posted February 25, 2015 Share Posted February 25, 2015 I have 8.09 as the mean of AVL? Maybe just checked the wrong plume or something. Regardless they're quite skewed due to the ARW family. No, you're right. It looks like I didn't count the upslope snowfall after the main event. I'm surprised to see the mean jump to 7.5" here. Kind of crazy... I'm thinking 3-6" is a good call here at the moment, in any case. Maybe 4-8". If you look at GSO's means by SREF family: ARW: 12.99" (max: 14.56", min: 11.67") NMB: 5.94" (max: 9.47", min: 4.73") NMM: 4.03" (max: 6.23", min: 2.22") Link to comment Share on other sites More sharing options...
jacobr57 Posted February 25, 2015 Share Posted February 25, 2015 No, you're right. It looks like I didn't count the upslope snowfall after the main event. I'm surprised to see the mean jump to 7.5" here. Kind of crazy... I'm thinking 3-6" is a good call here at the moment, in any case. Maybe 4-8". Yea, it's definitely a good run for around here. Even taking the median instead of the mean to account for some of that ARW skew leaves Asheville with 7.3 inches or so. Definitely clustered in the 6 inch range though. Link to comment Share on other sites More sharing options...
superjames1992 Posted February 25, 2015 Share Posted February 25, 2015 Yea, it's definitely a good run for around here. Even taking the median instead of the mean to account for some of that ARW skew leaves Asheville with 7.3 inches or so. Definitely clustered in the 6 inch range though. Indeed. Even the two "worst" model families show means of 4"+ and 6". Not bad... Looks like the 06z NAM is about to run, so let's see if we can get NAM'd one more time before hitting the sack for the night. Tomorrow will be the day of radar/satellite/water vapor hallucinations, HRRR/RAP meltdowns, etc. Link to comment Share on other sites More sharing options...
5statewx Posted February 25, 2015 Share Posted February 25, 2015 Euro ENS looks good. Link to comment Share on other sites More sharing options...
lilj4425 Posted February 25, 2015 Share Posted February 25, 2015 Only ONE SREF member has me getting no snow. Almost all of them are between 5-6 inches. Link to comment Share on other sites More sharing options...
superjames1992 Posted February 25, 2015 Share Posted February 25, 2015 The 06z NAM is tracking our surface low further inland into SW GA with h5 heights higher in front of the low. The LP position is near Albany, GA at hr 21 with CLT getting crushed and heavy precip arriving into GSO and RDU. N GA is getting crushed, as well. At hr 24, the low is at 1000 mb over SAV. CLT has gotten crushed, but isn't snow anymore as of this frame and RDU, after getting crushed, is now right in the dividing line, with southern Wake County no longer snow. Everything is shifted a good 50 miles west. That being said, with heavy rates, RDU and CLT could maybe stay snow (haven't looked at soundings to see how warm the warm nose is). Link to comment Share on other sites More sharing options...
DixieBlizzard Posted February 25, 2015 Share Posted February 25, 2015 The 06z NAM is tracking our surface low further inland into SW GA with h5 heights higher in front of the low. The LP position is near Albany, GA at hr 21 with CLT getting crushed and heavy precip arriving into GSO and RDU. N GA is getting crushed, as well. thanks for the pbp James. Link to comment Share on other sites More sharing options...
lilj4425 Posted February 25, 2015 Share Posted February 25, 2015 The 06z NAM is tracking our surface low further inland into SW GA with h5 heights higher in front of the low. The LP position is near Albany, GA at hr 21 with CLT getting crushed and heavy precip arriving into GSO and RDU. N GA is getting crushed, as well. I imagine the upstate looks good too if those areas do. Link to comment Share on other sites More sharing options...
superjames1992 Posted February 25, 2015 Share Posted February 25, 2015 I imagine the upstate looks good too if those areas do. GSP is presumably snow throughout. CLT and RDU get some serious precip, but they do mix in all likelihood. 999 mb LP just offshore of Emerald Isle at hr 27... 996 mb LP ~100 mile offshore of Hatteras at hr 30... Link to comment Share on other sites More sharing options...
5statewx Posted February 25, 2015 Share Posted February 25, 2015 06z NAM isn't much different track wise, but takes heaviest batch of moisture over land in the Carolina's. Widespread 1.25-1.5" QPF Through hour 30---NAM is known for being too wet, but the fact that this run actually got wetter is intriguing. Verbatim, mixing would likely reach RDU&CLT... but just to the N and W is most/all snow with amounts locally up to and over a foot. Link to comment Share on other sites More sharing options...
DixieBlizzard Posted February 25, 2015 Share Posted February 25, 2015 Man, I hope this thing is as wet as advertised. Link to comment Share on other sites More sharing options...
superjames1992 Posted February 25, 2015 Share Posted February 25, 2015 Here is a weenie snow map. I think a decent bit of what falls in E NC is not snow (verbatim), however. Link to comment Share on other sites More sharing options...
LovingGulfLows Posted February 25, 2015 Share Posted February 25, 2015 NAM continues to trend better for my area. 2-3 inches based on that map. I was getting nothing just 2 run cycles ago. Link to comment Share on other sites More sharing options...
superjames1992 Posted February 25, 2015 Share Posted February 25, 2015 You know, looking at RDU's and CLT's Skew-Ts on the NAM, they really might be able to stay all-snow, though. It's really, really close and rates are intense. Might go isothermal and get heavy paste. Of course, ratios would probably suck and those maps us 10:1 ratios, so they would be overdone. GSO is comfortably a snow sounding throughout. Link to comment Share on other sites More sharing options...
DixieBlizzard Posted February 25, 2015 Share Posted February 25, 2015 You know, looking at RDU's and CLT's Skew-Ts on the NAM, they really might be able to stay all-snow, though. It's really, really close and rates are intense. Might go isothermal and get heavy paste. That would be amazing for those guys. Link to comment Share on other sites More sharing options...
lilj4425 Posted February 25, 2015 Share Posted February 25, 2015 Here is a weenie snow map. I think a decent bit of what falls in E NC is not snow (verbatim), however. Good thing that was posted at 3am. You would have weenies running rampant around here like horny rabbits if it was posted 12 hours earlier or later. Link to comment Share on other sites More sharing options...
Jet Stream Rider Posted February 25, 2015 Share Posted February 25, 2015 GSP is presumably snow throughout. CLT and RDU get some serious precip, but they do mix in all likelihood. 999 mb LP just offshore of Emerald Isle at hr 27... 996 mb LP ~100 mile offshore of Hatteras at hr 30... Loving this track! The low comes from deep in the western gom and ends up off Hatteras. Track of the big dog. Although the pressure isn't so deep, it should be deep enough. Wow! Here it is at hr 15 near the mouth of the Mississippi. Link to comment Share on other sites More sharing options...
5statewx Posted February 25, 2015 Share Posted February 25, 2015 Newest WPC 4"+ ... rest isn't out yet. Link to comment Share on other sites More sharing options...
superjames1992 Posted February 25, 2015 Share Posted February 25, 2015 Looks like the 4 km NAM is unsurprisingly following its 12 km twin and shifting heavy precip N/W. It has a 1000 mb LP right offshore of Myrtle Beach at hr 24. Link to comment Share on other sites More sharing options...
wxduncan Posted February 25, 2015 Share Posted February 25, 2015 Latest From GSP: .NEAR TERM /THROUGH TONIGHT/...AS OF 330 AM EST WEDNESDAY...SIGNIFICANT WINTER STORM STILL ON TRACKTO OVERTAKE THE REGION WEDNESDAY AFTERNOON/NIGHT. DEVELOPINGSURFACE CYCLONE AIDED BY EASTWARD ADVECTING POTENT UPPER SHORT WAVEIS GAINING STEAM ACROSS SOUTH TEXAS INTO THE WESTERN GULF THISMORNING. THIS SURFACE WAVE IS STILL PROGGED TO SLIDE ALONG THE GULFCOAST CROSSING NORTH FL...SOUTHERN GA/SC THIS EVENING. MODELS STILLTRANSLATE AMPLE QPF RESPONSE ATOP THE REGION BY WAY OF ENHANCEDUPGLIDE AIDED BY COUPLED JET ALOFT PROVIDING NICE UPPER SUPPORT.LIKEWISE...LATEST NAM12 ANALYSIS INDICATES AMPLE H7 FRONTOGENESISALONG THE NORTHERN FLANK OF THE SYSTEM AS IT SLIDES BY TO THE SOUTHAROUND THE 21Z-03Z TIMEFRAME. GIVEN ALL THE ABOVE...WOULD NOT BESURPRISED TO SEE IMPRESSIVE MESOSCALE BANDING OF SNOWFALL WITH THISSYSTEM. HIGH PRESSURE TO THE NORTH WILL BE ON THE MOVE WITH MODESTSURFACE COLD ADVECTION ASSOCIATED WITH IT. THE PRIMARY FCSTCHALLENGE WITH THIS SYSTEM IS WHERE/WHEN WILL THE RASN/SN LINE SETUPTHIS EVENING...AND HOW DOES THAT LINE UP WITH FCST QPF.FCST FEATURES INCREASING POPS FROM THE SOUTHWEST JUST BEFORE NOONWITH THERMAL PROFILES SUPPORTING ALL RAIN. FURTHER INTO THEAFTERNOON POPS SPREAD NORTH OVER THE SOUTHWEST NC MOUNTAINS...ALL OFNORTHEAST GA AND THE WESTERN HALF OF THE SC UPSTATE...BEFOREOVERTAKING THE NC PIEDMONT BY EARLY EVENING. AS PRECIP SLIDESIN...EXPECTING WETBULB EFFECTS TO ASSIST IN COOLING OF TEMPS THROUGHTHE LOW LEVELS...ALONG WITH GOOD DYNAMIC COOLING DUE TO THE INTENSEUPWARD MOTION BENEATH ABOVE MENTIONED COUPLED UPPER JET MAXIMA.THUS...EXPECTING RAIN TO CHANGE OVER TO SNOW ALONG OR JUST SOUTH OFI85 AROUND THE 6PM TIMEFRAME ACROSS GA/SC...THEN AN HOUR OR SO LATEROVER NC. IT IS ALSO AT THIS TIME WHEN IT IS FCST THAT MESOSCALEBANDING COULD OCCUR YIELDING POSSIBLE SNOWFALL RATES ON THE ORDER OF1-2 INCHES PER HOUR. ITS NEARLY IMPOSSIBLE TO DETERMINE EXACTLYWHERE THIS WILL OCCUR...AS WITH THE RAIN/SNOW LINE...BUT IT LOOKSTHAT THE I85 CORRIDOR IS LIKELY TO BE THE MOST FAVORABLE LOCATION.AS ALWAYS...DUE TO THE UNCERTAINTY OF ALL THESE FEATURESALIGNING...SNOW TOTALS COULD BE GREATLY AFFECTED OVER A SMALL...SAY30M AREA. AS FOR SNOW TOTALS...BLENDED IN HPC QPF WITH A TOUCH OFSREF AND ENDING UP WITH THE HEAVIEST AMOUNTS...IN THE 6-8 INCH RANGEALONG AND JUST NORTH OF I85...WITH AMOUNTS TAPERING A BIT FURTHERNORTH DUE TO PROXIMITY FROM QPF MAXIMA. SOUTH OF I85 EXPECTING THEMIXED PTYPE TO POSSIBLY AFFECT SNOW TOTALS SIGNIFICANTLY...WHEREGENERALLY 3-5 INCHES IS FCST. SNOW WILL CONTINUE THROUGH THEOVERNIGHT WITH INTENSITY BACKING OFF AS PRIMARY UPPER FORCING EXITSEAST. THUS...POPS REMAIN IN THE LIKELY RANGE UP UNTIL DAYBREAKTHURSDAY WHERE THEY TAPER FROM THE WEST TO CHANCE LEVELS WHEREPOSSIBLE DEFORMATION ZONE COULD ALLOW FOR FURTHER CONTINUATION OFSNOWFALL. Link to comment Share on other sites More sharing options...
5statewx Posted February 25, 2015 Share Posted February 25, 2015 06z GFS coming in a hair stronger and west. Track actually matches 06z NAM very well. Link to comment Share on other sites More sharing options...
JoshWeather Posted February 25, 2015 Share Posted February 25, 2015 The charlotte area seems to consistently be in the 3-5 inch area. Looks like jackpot could be anywhere from raleigh to NE NC in a line Link to comment Share on other sites More sharing options...
5statewx Posted February 25, 2015 Share Posted February 25, 2015 Looking at all the data... not one model shows snowfall totals under 6" for RDU. I'll take my chances Link to comment Share on other sites More sharing options...
Snow dog Posted February 25, 2015 Share Posted February 25, 2015 day1_psnow_gt_04.gifNewest WPC 4"+ ... rest isn't out yet. For upstate crowd, this map should put any concerns of a nice snow to bed. Nice little bullseye over Greenville! Link to comment Share on other sites More sharing options...
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