RaleighWx Posted February 25, 2015 Share Posted February 25, 2015 One thing I think may being missed with regards to overcoming boundary layer warmth, particularly with the triangle, is that amount of dry air in the 700-900mb layer. Dewpoints are -15 to -20C in that layer tomorrow afternoon. Once precip falls into that, evaparational cooling will knock temps down quickly, and that cold air will transfer to the surface with precipitation. That is why temps fall at the surface even though surface wet bulbs are above freezing. Link to comment Share on other sites More sharing options...
LovingGulfLows Posted February 25, 2015 Share Posted February 25, 2015 My money right now is that's going to come south 30-40 miles but I've been wrong before If that happens, I will cry tears of happiness. It would be put in the purple. I can definitely see it happening it we get colder 800 temps. The rain/snow line sets up about 10-15 miles south of central Atlanta. Link to comment Share on other sites More sharing options...
Portsmouth Weather Posted February 25, 2015 Share Posted February 25, 2015 Crap, I'm in the DT bullseye of 8-10. Those start times don't make any sense. In the bullseye as well. I'm feeling good about this storm!! Link to comment Share on other sites More sharing options...
WxJordan Posted February 25, 2015 Share Posted February 25, 2015 MY FIRST CALL MAP.... There will be surprises from this system, and someone will receive a lot of snow. I would not be shocked to hear some totals of 12 inches of snow, especially in the northeast part of NC and southeastern VA. Some areas could see bands of snow putting down 2-3 inches per hour. Crazy rates will be likely across the southeast. Thundersnow will also be possible as the storm deepens off the eastern seaboard. The difficult part of this forecast is determining where that elusive rain/snow line will set up. This map does a decent job at determining where that rain/snow line will set up; however, it may shift 30-50 miles depending on the final track of the storm. The energy at 500 mb is really strong, and this is what makes this storm different compared to the storm last week. The upper level dynamics are better, and thus I think precipitation totals will be higher as well. I actually think most areas east of the Blue Ridge will see over .5 of an inch of precipitation from the event in just 9 hours. Raleigh could see over an inch of precipitation from this event. There is no doubt this will be a fun storm to track, and I am looking forward to seeing what this storm produces. To read more about my opinions on this storm, you can visit my website: http://wxjordan.com/weather-forecast/forecast/184-major-winter-storm-brings-big-snow-to-southeast-united-states Link to comment Share on other sites More sharing options...
SnowGoose69 Posted February 25, 2015 Share Posted February 25, 2015 One thing I think may being missed with regards to overcoming boundary layer warmth, particularly with the triangle, is that amount of dry air in the 700-900mb layer. Dewpoints are -15 to -20C in that layer tomorrow afternoon. Once precip falls into that, evaparational cooling will knock temps down quickly, and that cold air will transfer to the surface with precipitation. That is why temps fall at the surface even though surface wet bulbs are above freezing. That's what worries me near Atlanta and they have the advantage of it occurring earlier before much heating occurs, same thing there with tons of dry air in that layer and the WAA just isnt that strong on most models below 800mb other than the NAM, if it cools below 0C it's probably going to stay there Link to comment Share on other sites More sharing options...
Tony Sisk Posted February 25, 2015 Share Posted February 25, 2015 Crap, I'm in the DT bullseye of 8-10. Those start times don't make any sense. I'm assuming the PM times should be WD and not TH 4 PM Wednesday 7 PM Wednesday Link to comment Share on other sites More sharing options...
mikepie Posted February 25, 2015 Share Posted February 25, 2015 That's what worries me near Atlanta and they have the advantage of it occurring earlier before much heating occurs, same thing there with tons of dry air in that layer and the WAA just isnt that strong on most models below 800mb other than the NAM, if it cools below 0C it's probably going to stay there I live 2 miles N of the Airport and noticed I could clearly see the moon when I was just walking my dogs. Curious to see if we can get some good surface cooling and maybe lock in some cooler surface temps. We already busted today, FFC had me getting to 43 but only got to 37 or so. Link to comment Share on other sites More sharing options...
JacobNC Posted February 25, 2015 Share Posted February 25, 2015 Jon Cash, former WAVY-TV Met says: "...Some models paint 2-5” of snow while others bring in a foot! Which one is correct? This is where meteorologists earn their paychecks! Here’s my thinking. Almost every storm coming from this direction this year has moved further north than advertised. Hence, the higher snow totals are the more likely scenario. The rain snow line will be located on a line from just south of Elizabeth City and Kill Devil Hills. Hence, it appears this will be a snow event for the metro Hampton Roads area with parts of Carolina possibly mixing with rain if that line moves a bit further north than predicted. Temps will be in the upper 20s during the event and the snow will stick to all the roads. It is highly doubtful there will be school Thursday or Friday and even tomorrow it will be in question due to the snow currently falling. Here’s my first attempt at snowfall totals. I will adjust this again sometime tomorrow before the storm moves in..." Snow Totals for Wednesday night into Thursday morning. Southside (VA Beach, Norfolk, Chesapeake, Portsmouth) 8-12” Suffolk 6-10” Franklin 5-9” Smithfield 4-8” Hampton 6-10” Newport News 6-10” Williamsburg 4-8” Gloucester 3-7” Eastern Shore 6-12” Elizabeth City 4-12” (dependent on switch to rain?) Edenton 4-12” (dependent on switch to rain?) Outer Banks 1-12” lowest Hatteras and highest Corolla Amazing how within just one county (Dare) you could have people getting all rain and others getting a foot of snow. Link to comment Share on other sites More sharing options...
RaleighWx Posted February 25, 2015 Share Posted February 25, 2015 That's what worries me near Atlanta and they have the advantage of it occurring earlier before much heating occurs, same thing there with tons of dry air in that layer and the WAA just isnt that strong on most models below 800mb other than the NAM, if it cools below 0C it's probably going to stay there I certainly dont envy forecasters for Atlanta. I feel RDU is relatively easy compared to them. Link to comment Share on other sites More sharing options...
deltadog03 Posted February 25, 2015 Share Posted February 25, 2015 btw, snow could get an early start per rap with the finger of snow. I wouldn't be too surprised if far western areas of georgia saw something as early as 15z. also...the rap is south of the nam at 18 hours with the surface low I actually think things trend quicker and colder, with some south drift tonight. Link to comment Share on other sites More sharing options...
deltadog03 Posted February 25, 2015 Share Posted February 25, 2015 there is actually many breaks in the clouds tonight. Link to comment Share on other sites More sharing options...
SN_Lover Posted February 25, 2015 Share Posted February 25, 2015 SREF looks worse and worse for CLT. Lets see what the models do tonight. Link to comment Share on other sites More sharing options...
deltadog03 Posted February 25, 2015 Share Posted February 25, 2015 How about WAA for everyone south of Canada?? and rain for everyone? Link to comment Share on other sites More sharing options...
BIG FROSTY Posted February 25, 2015 Share Posted February 25, 2015 How about WAA for everyone south of Canada?? and rain for everyone? lol, Only if you can get temps up to 70! So we can play some golf!!! Link to comment Share on other sites More sharing options...
wake4est Posted February 25, 2015 Share Posted February 25, 2015 Robert's call. Link to comment Share on other sites More sharing options...
wxduncan Posted February 25, 2015 Share Posted February 25, 2015 Latest video update from Brad Panovich: https://www.youtube.com/watch?v=2XfzMr1bz2w&feature=youtu.be&a Link to comment Share on other sites More sharing options...
superjames1992 Posted February 25, 2015 Share Posted February 25, 2015 Looks like the SREF is coming in less insanely amped with precipitation. Maybe the Apps Running members are now gone. Link to comment Share on other sites More sharing options...
LovingGulfLows Posted February 25, 2015 Share Posted February 25, 2015 Robert's map actually looks good tbh. Could definitely see that happening. Link to comment Share on other sites More sharing options...
Isopycnic Posted February 25, 2015 Share Posted February 25, 2015 Latest video update from Brad Panovich: https://www.youtube.com/watch?v=2XfzMr1bz2w&feature=youtu.be&a Link to comment Share on other sites More sharing options...
griteater Posted February 25, 2015 Share Posted February 25, 2015 Euro Ens Mean QPF has been a little higher than the Op in each of the last 3 runs for CLT. For 12z, the mean was a little higher than the Op for CLT, RDU, and GSO. I suppose the higher res Op runs should get more weight, but the higher mean values are nice to see. Link to comment Share on other sites More sharing options...
packfan98 Posted February 25, 2015 Share Posted February 25, 2015 Looks like the SREF is coming in less insanely amped with precipitation. Maybe the Apps Running members are now gone. ] I'm betting that will also result in a colder run. Link to comment Share on other sites More sharing options...
GaWx Posted February 25, 2015 Share Posted February 25, 2015 Regarding whether or not KATL is mainly rain, does anyone recall the great 3/24/1983 snow? KATL got the heaviest snow since 1940. From what I was told by someone in Cobb county, nobody expected it to be snow. It turned out to be a mainly very wet snow with huge flakes. I wasn't in ATL to experience it. Could this end up similar? Opinions? Link to comment Share on other sites More sharing options...
SnowGoose69 Posted February 25, 2015 Share Posted February 25, 2015 So far looking at the precip in NM and TX the NAM/GFS are not even close, the 18Z NAM was better than the 12Z but both the 12 and 18Z GFS/NAM runs are verifying too slow and too far NW as a general idea. The RGEM/Euro are closer to reality, does not mean this will translate downstream though. Link to comment Share on other sites More sharing options...
griteater Posted February 25, 2015 Share Posted February 25, 2015 PROBABILISTIC HEAVY SNOW AND ICING DISCUSSION NWS WEATHER PREDICTION CENTER COLLEGE PARK MD 440 PM EST TUE FEB 24 2015 VALID 00Z WED FEB 25 2015 - 00Z SAT FEB 28 2015 ...SRN PLAINS/LOWER MS VALLEY TO THE SOUTHERN APPALACHIANS/SOUTHEAST/MID-ATL... A VERY COMPLEX FORECAST FOR THE SOUTHERN TIER OF THE COUNTRY ON WED AND THURS.... AS AN ACTIVE SRN BRANCH WITH GULF OF MEXICO AND SUBTROPICAL MOISTURE INTERACTS WITH POLAR AND ARCTIC HIGH PRESSURE FOR THE THREAT OF EXTENSIVE WINTER WEATHER. A CLOSED MID TO UPPER LOW OVER AZ/NM WILL EJECT OUT IN THE SRN PLAINS/LOWER MS VALLEY ON WED AND PROGRESS ALONG THE FAST SRN BRANCH INTO THE SOUTHEAST LATE WED INTO THURS. THIS SYSTEM SHOULD BEGIN TO TAP A BRIEF BUT ANOMALOUS SURGE IN LL MOISTURE FROM THE GULF OF MEXICO WITH PWS AOA 1 TO 2 TIMES ABOVE STANDARDIZED ANOMALIES. THIS MOISTURE WILL OVERRUN A FORMING BAROCLINIC ZONE NEAR THE CENTRAL GULF COAST AND MODEL THERMAL PROFILES SUGGEST POSSIBLE STREAK OF HEAVY SNOW AND NARROW TRANSITION ZONE FROM NERN TX TO NRN GA/SRN APPALACHIANS... WITH THE HEAVIEST FROZEN PRECIP ACROSS NERN TX/SRN AR/NRN MS/AL INTO NRN GA. AS A SURFACE LOW DEVELOPS AND ARRIVES TO JUST OFFSHORE OF THE FL PANHANDLE LATE WED... THIS LOW WILL JUMP TO THE CAROLINAS COAST BY THURS MORNING. THIS SHOULD RESULT IN A POTENTIALLY DECENT DYNAMIC COOLING REGIME FROM NRN GA/ERN TN THROUGH NC/SRN VA AND PERHAPS FARTHER NORTH. THIS ENTIRE FCST SOUNDS FAIRLY STRAIGHT FORWARD... HOWEVER A DECENT AMOUNT OF SPREAD EXISTS WITH THE GUIDANCE. THE CLEAR TREND OVER THE PAST 24 HRS IS A CONTINUED TREND TO THE NORTH WITH THE EXTENSION OF THE DEVELOPING PRECIP SHIELD. THE 12Z NAM/09Z SREF MEAN ARE AN ACTUAL CLEAR OVER-AMPLIFIED SOLUTION... WHILE THE GFS/ECMWF ARE MORE SUBDUED. WPC BOUGHT THE NORTHWARD TREND BUT REMAINED CONSERVATIVE IN RELYING CLOSE TO THE GLOBAL DUO OF THE GFS/ECMWF THROUGHOUT. THIS MEANS DRAWING SNOW FARTHER NORTH INTO PARTS OF THE TN VALLEY/APPALACHIANS AND MID-ATL REGION. THIS FCST REMAINS FLUID ESPECIALLY THURS FOR A REGION SUSCEPTIBLE TO ANY WINTER WEATHER INVOLVING AN ACTIVE SRN STREAM... PLENTY OF MOISTURE AND ARCTIC AIR. Link to comment Share on other sites More sharing options...
SnowGoose69 Posted February 25, 2015 Share Posted February 25, 2015 Regarding whether or not KATL is mainly rain, does anyone recall the great 3/24/1983 snow? KATL got the heaviest snow since 1949. From what I was told by someone in Cobb county, nobody expected it to be snow. It turned out to be a mainly very wet snow with huge flakes. I wasn't in ATL to experience it. Could this end up similar? Opinions? Here it is.....the setup looked colder with more cold air in place with a more south track of the upper lows http://mp1.met.psu.edu/~fxg1/NARR/1983/us0324.php I checked out CIPS today and no setup really resembled this with the surface low so far south yet the 500 low relatively far north....1/24/91 I thought was the closest one overall and it was not a spectacular match Link to comment Share on other sites More sharing options...
J.C. Posted February 25, 2015 Share Posted February 25, 2015 Robert's call. This is the third forecast map I've seen on this thread in the past hour that includes the CAE area, and points northwest. Most of the models are showing a rain-snow line inverted up toward the I-85 corridor from ATL and points east, not flat following I-20 east of Atlanta. Forecasters must be drawing these maps from knowledge and experience. Link to comment Share on other sites More sharing options...
Tacoma Posted February 25, 2015 Share Posted February 25, 2015 Robert showing Asheville and surrounding area in a swath of 8+ inches and said if deformation band comes thru like its looking could be up to 12 in areas of that swath of 8+. Link to comment Share on other sites More sharing options...
No snow for you Posted February 25, 2015 Share Posted February 25, 2015 So far looking at the precip in NM and TX the NAM/GFS are not even close, the 18Z NAM was better than the 12Z but both the 12 and 18Z GFS/NAM runs are verifying too slow and too far NW as a general idea. The RGEM/Euro are closer to reality, does not mean this will translate downstream though. That is great news. I really want to see how much moisture it can pick up in the gulf and bring up here. Was it you that said the Temps out there had busted to the low side? Link to comment Share on other sites More sharing options...
Cold Rain Posted February 25, 2015 Share Posted February 25, 2015 Robert showing Asheville and surrounding area in a swath of 8+ inches and said if deformation band comes thru like its looking could be up to 12 in areas of that swath of 8+. He's got the classic snow hole right over the Triangle where it belongs. Good forecast. In other news, the most important NAM run of the season on tap. 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/ Link to comment Share on other sites More sharing options...
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