Gastonwxman Posted January 5, 2011 Share Posted January 5, 2011 What was going on with the GGEM at the hr. 126? It had a 0 850 spot surrounding the NC/SC/GA/TN border area. Never understood why the modeling does that sometimes. Link to comment Share on other sites More sharing options...
phil882 Posted January 5, 2011 Share Posted January 5, 2011 What was going on with the GGEM at the hr. 126? It had a 0 850 spot surrounding the NC/SC/GA/TN border area. Never understood why the modeling does that sometimes. Well keep in mind that when the 850mb temperatures are just a slight bit above 0 degrees C, the dewpoint is likely quite a bit below 0 degrees C. This is especially true in CAD regimes, where cold dry air filters down from northerly locations. In essence, when the atmosphere starts to saturate due to precipitation, the temperature falls not only at the surface, but also aloft due to evaporational cooling as the atmosphere attempts to moisten up. Thus, you can see small circles of sub 0 degree C air at 850mb where precipitation has just started to invade a region thanks to evaporational cooling. Does that explain it? Its quite common to see this in the southeast, since we are often just slightly too warm before precipitation invades the area. Link to comment Share on other sites More sharing options...
Gastonwxman Posted January 5, 2011 Share Posted January 5, 2011 Well keep in mind that when the 850mb temperatures are just a slight bit above 0 degrees C, the dewpoint is likely quite a bit below 0 degrees C. This is especially true in CAD regimes, where cold dry air filters down from northerly locations. In essence, when the atmosphere starts to saturate due to precipitation, the temperature falls not only at the surface, but also aloft due to evaporational cooling as the atmosphere attempts to moisten up. Thus, you can see small circles of sub 0 degree C air at 850mb where precipitation has just started to invade a region thanks to evaporational cooling. Does that explain it? Its quite common to see this in the southeast, since we are often just slightly too warm before precipitation invades the area. Indeed it does. Thanks for taking the time to clarify this for me. I had someone ask me earlier what it meant, but couldn't give them an answer. Link to comment Share on other sites More sharing options...
NCSNOW Posted January 5, 2011 Share Posted January 5, 2011 Thanks Lookout/Phil for annalysis last night; Where we are at, at the moment; Nice trend is shaping up with potential southeast snowstorm for late weekend. We have 2 models with a similar forecast that is carrying some weight since one of them is the euro with 2 consecutive runs inside 5 days now. Add to this flavor the Nam at hr 84 showing something similar and now the 6z gfs trending toward the same idea ,its plausible to start getting exicited. It will take a few more days to nail down the exact details, but things in model world are starting to fall in line with the pattern that is evolving. Kudos to Allen, Robert and others for recognizing the potential that exist due to the pattern we are entering. Hopefully everyone in the SE can get some white carpet laid down and make the future long cold snap more enjoyable. Here is the 6z gfs. It still weakens out the lead shortwave, then comes back on day 7 and gets the second shortwave going pretty good for NC. But atleast the low is not heading to Cuba or Lake Michigan this run. Link to comment Share on other sites More sharing options...
burgertime Posted January 5, 2011 Share Posted January 5, 2011 Wow at the GGEM and the Euro, great runs for sure. Robert hit the nail on the head calling that the Euro last night would have a superb solution and sure enough it did. Link to comment Share on other sites More sharing options...
burgertime Posted January 5, 2011 Share Posted January 5, 2011 Well keep in mind that when the 850mb temperatures are just a slight bit above 0 degrees C, the dewpoint is likely quite a bit below 0 degrees C. This is especially true in CAD regimes, where cold dry air filters down from northerly locations. In essence, when the atmosphere starts to saturate due to precipitation, the temperature falls not only at the surface, but also aloft due to evaporational cooling as the atmosphere attempts to moisten up. Thus, you can see small circles of sub 0 degree C air at 850mb where precipitation has just started to invade a region thanks to evaporational cooling. Does that explain it? Its quite common to see this in the southeast, since we are often just slightly too warm before precipitation invades the area. Dude why do you not have a red tag? Or at least a yellow pro forecaster tag? Link to comment Share on other sites More sharing options...
DaculaWeather Posted January 5, 2011 Share Posted January 5, 2011 Nice summary NCSnow. Thanks! The first thing I do when I get up is come read what happened last night! Birmingham is starting to get on the bandwagon for this weekend in their AFD. Lot's of moisture headed our way it appears, for Alabama it's all a rain event.http://www.daculawea...wide_master.php GSP just in 6:28am Link to comment Share on other sites More sharing options...
phil882 Posted January 5, 2011 Share Posted January 5, 2011 Finally had a chance to post my thoughts this morning... lots to talk about but I focused on the threat for today since its the most pressing... there will be time to talk about the system this weekend soon! http://blizzard.atms.unca.edu/~pppapin/local_jan.html Link to comment Share on other sites More sharing options...
DaculaWeather Posted January 5, 2011 Share Posted January 5, 2011 FFC's AFD is wishy-washy as usual Link to comment Share on other sites More sharing options...
Psalm 148:8 Posted January 5, 2011 Share Posted January 5, 2011 FFC's AFD is wishy-washy as usual Here's where they fess up: 550 AM EST WED JAN 5 2011 THIS HAZARDOUS WEATHER OUTLOOK IS FOR NORTH AND CENTRAL GEORGIA. .DAY ONE...TODAY AND TONIGHT NO HAZARDOUS WEATHER IS EXPECTED AT THIS TIME. .SYNOPSIS... AN UPPER LEVEL STORM SYSTEM WILL MOVE TOWARD GEORGIA TODAY BRINGING RAIN TO MOST AREAS THROUGH TONIGHT. .DAYS TWO THROUGH SEVEN...THURSDAY THROUGH TUESDAY SOME COMPUTER FORECASTS INDICATE SNOW MAY BE POSSIBLE ACROSS NORTH GEORGIA ON SUNDAY. STAY TUNED FOR LATER FORECASTS ON THIS POSSIBLE WINTER WEATHER EVENT. OTHERWISE...NO HAZARDOUS WEATHER IS EXPECTED AT THIS TIME. Link to comment Share on other sites More sharing options...
Itunis Posted January 5, 2011 Share Posted January 5, 2011 Here's where they fess up: 550 AM EST WED JAN 5 2011 THIS HAZARDOUS WEATHER OUTLOOK IS FOR NORTH AND CENTRAL GEORGIA. .DAY ONE...TODAY AND TONIGHT NO HAZARDOUS WEATHER IS EXPECTED AT THIS TIME. .SYNOPSIS... AN UPPER LEVEL STORM SYSTEM WILL MOVE TOWARD GEORGIA TODAY BRINGING RAIN TO MOST AREAS THROUGH TONIGHT. .DAYS TWO THROUGH SEVEN...THURSDAY THROUGH TUESDAY SOME COMPUTER FORECASTS INDICATE SNOW MAY BE POSSIBLE ACROSS NORTH GEORGIA ON SUNDAY. STAY TUNED FOR LATER FORECASTS ON THIS POSSIBLE WINTER WEATHER EVENT. OTHERWISE...NO HAZARDOUS WEATHER IS EXPECTED AT THIS TIME. Hey, at this point and with waffling models there is no way for them to pin down what will happen. I think they're doing OK so far. Get a few more model runs under our belts (and reduce the divergence between models) and then they'll start being more bullish. Link to comment Share on other sites More sharing options...
Weather Czar Posted January 5, 2011 Share Posted January 5, 2011 As A weenie I really hope the whole 240 hour run of the CMC will verify! Major hit this weekend and next Friday with extreme cold. Link to comment Share on other sites More sharing options...
Local Yokel Wx Posted January 5, 2011 Share Posted January 5, 2011 Finally had a chance to post my thoughts this morning... lots to talk about but I focused on the threat for today since its the most pressing... there will be time to talk about the system this weekend soon! http://blizzard.atms.../local_jan.html Phil, Thanks for keeping us mtn folks feed with great disco! Big fan of your work and more so since you're only 20 min away! Link to comment Share on other sites More sharing options...
Lowpressure Posted January 5, 2011 Share Posted January 5, 2011 Very nice write up Phil. Seems reasonable and well thought out. Good work. Link to comment Share on other sites More sharing options...
GaWx Posted January 5, 2011 Share Posted January 5, 2011 Sorry, for me the Euro is a better solution..... Agreed 100% for ATL. It isn't even close IF one wants snow over IP/ZR. The 0Z Euro is a major snow with 850's below 0C with ~0.70" of qpf! That should be enough for 5-6" of snow even allowing for some leeway due to initial melting and possible overestimation of qpf. This scenario is about as good as it gets for ATL with a near perfect Miller A track across N FL. It would be the biggest moderate to strong La Nina snowstorm for ATL since 2/1894! OTOH, the GGEM's low track is too far north for much, if any, snow at ATL. The Miller A low tracks to near Savannah instead of N FL or far SE GA.. Also, the 850's are too warm..so it would be almost all IP/ZR/R. Then again, it could be a doozy of an IP/ZR storm if there is enough cold/dry wedging due to a whopping ~1`" qpf!. So, if that is what one wanted over snow, it is likely better for them. Link to comment Share on other sites More sharing options...
Poimen Posted January 5, 2011 Share Posted January 5, 2011 HPC is discounting the GGEM at this time (no surprise). However, the discussion this morning throws us a bone I believe: AFTER GUIDANCE GENERALLY TRENDED FASTER/MORE AMPLIFIED WITH W-CNTRL CONUS FLOW IN THE PRIOR 24 HRS... SOLNS NOW REFLECT SOME MODERATION AWAY FROM THAT IDEA AND AS A RESULT THE LEADING SRN STREAM SHRTWV IS MORE SUPPRESSED AS REFLECTED IN MOST GUIDANCE FROM BEFORE YDAY. THE GFS AND CMC ARE THE LEAST AMPLIFIED BY EARLY NEXT WEEK BUT THE CMC HAS AN OUTLIER EVOLUTION OVER THE ERN PAC WHICH ARGUES FOR DISCOUNTING ITS SOLN. GIVEN THE DEVELOPMENT OF DAILY OSCILLATION IN GUIDANCE... AN INTERMEDIATE SOLN COMPOSED OF THE 00Z ECMWF AND 12Z ECMWF ENSEMBLE MEAN APPEARS TO BE THE BEST OPTION THRU AT LEAST THE WEEKEND. LATER IN THE PERIOD THE GEFS MEAN JOINS THE ECMWF MEAN ALOFT... AND IN SHOWING WRN ATLC SFC DEVELOPMENT CLOSER TO THE COAST THAN THE OPERATIONAL GFS/ECMWF. TYPICAL DIFFICULTY THAT GUIDANCE HAS WITH IMPORTANT DETAILS BEYOND 2-3 DAYS WOULD RECOMMEND A COMPROMISE BETWEEN THESE TWO CLUSTERS AS A STARTING POINT. If that development occurs along the GA/SC coast then many of us should be in business. Link to comment Share on other sites More sharing options...
strongwxnc Posted January 5, 2011 Share Posted January 5, 2011 Great Disco last night folks. So will the models converge today or continue to make us draws lines in the sand or bring out the box or horse shoes ? Link to comment Share on other sites More sharing options...
Poimen Posted January 5, 2011 Share Posted January 5, 2011 I can't believe no one has talked about the DGEX yet. I know this model generally stinks but I think it is hinting at something close to what HPC is talking about this morning. The initial wave dampens out as it crosses Florida but then redevelops off the SE coast as the next upper disturbance comes in from the west: Link to comment Share on other sites More sharing options...
WeatherNC Posted January 5, 2011 Share Posted January 5, 2011 I can't believe no one has talked about the DGEX yet. Link to comment Share on other sites More sharing options...
Amos83 Posted January 5, 2011 Share Posted January 5, 2011 Great Disco last night folks. So will the models converge today or continue to make us draws lines in the sand or bring out the box or horse shoes ? I tend to believe the models will still have problems today. The pattern is extreme so modeling with have a hard time with each wave and where everything sets up show until more pieces are in play. I would look to see if the 12z EURO today continues with its trend from yesterday's 12z and 0z runs to see if it can develop some consistency. IF the 12z is still showing a good hit for Sunday night/Monday for the SE that will be 3 runs in a row and I'll begin to get a little excited. I believe the EURO did a pretty good job yesterday, like Foothills was saying, and think in the end it will be a east/west tracking storm where a good chunk of Tenn, N. AL, N. GA, W. SC, and NC end up getting a nice event. However a lot can change...... Link to comment Share on other sites More sharing options...
Poimen Posted January 5, 2011 Share Posted January 5, 2011 lol yeah, that map looks kind of familiar! Link to comment Share on other sites More sharing options...
Amos83 Posted January 5, 2011 Share Posted January 5, 2011 If the DGEX is correct the CLT triangle of absolute snow death would continue... a low dampening out as it moves into FL then redeveloping off the SE coast as depicted would leave a big snow hole between the CLT area and foothills. At least it is showing the potential for this weekend so I'll take it for now Link to comment Share on other sites More sharing options...
Poimen Posted January 5, 2011 Share Posted January 5, 2011 If the DGEX is correct the CLT triangle of absolute snow death would continue... a low dampening out as it moves into FL then redeveloping off the SE coast as depicted would leave a big snow hole between the CLT area and foothills. At least it is showing the potential for this weekend so I'll take it for now Yeah, but as you know the details are far from certain. Perhaps this will the type of system that brings good over running snows to most everyone and then the coastal takes over- or something along those lines. Something akin to March 1980. Who knows??? Link to comment Share on other sites More sharing options...
burgertime Posted January 5, 2011 Share Posted January 5, 2011 If the DGEX is correct the CLT triangle of absolute snow death would continue... a low dampening out as it moves into FL then redeveloping off the SE coast as depicted would leave a big snow hole between the CLT area and foothills. At least it is showing the potential for this weekend so I'll take it for now I've said it before and I'll say it again, if the DGEX has you with a foot of snow days away you have a better chance of getting zero....I prefer to not be in the bullseye on it As for your thoughts on the models, I think they finally are starting to get a handle on it. Look for the 12z GFS to come in agreement with the Euro and the Euro to continue it's solution. I really doubt we see a shift with the 12z runs. Just my gut feeling. I'm feeling really good about this system and the best thing about the 00z Euro and 6z GFS is that it kept us in NC cold enough for all snow. Link to comment Share on other sites More sharing options...
Amos83 Posted January 5, 2011 Share Posted January 5, 2011 Yeah, but as you know the details are far from certain. Perhaps this will the type of system that brings good over running snows to most everyone and then the coastal takes over- or something along those lines. Something akin to March 1980. Who knows??? Agree, I'm not saying it wont happen that way just what usually happens. Usually as redevelopment takes place like shown on the DGEX it pulls what precip is west toward the core thus leaving I-85 and points west screwed. I'm not saying that is what will happen but what could happen.... again this is the DGEX we are talking about so I'm not worried. Link to comment Share on other sites More sharing options...
Amos83 Posted January 5, 2011 Share Posted January 5, 2011 I've said it before and I'll say it again, if the DGEX has you with a foot of snow days away you have a better chance of getting zero....I prefer to not be in the bullseye on it As for your thoughts on the models, I think they finally are starting to get a handle on it. Look for the 12z GFS to come in agreement with the Euro and the Euro to continue it's solution. I really doubt we see a shift with the 12z runs. Just my gut feeling. I'm feeling really good about this system and the best thing about the 00z Euro and 6z GFS is that it kept us in NC cold enough for all snow. I agree Burger..... it all about trends. I'm liking what the trends have been over the past 24 hours and hope to see them continue. What I meant was that I don't think the major models will all be in agreement yet. However I think we will continue to see them trend toward a good snow event for a lot of us. Either way the next couple of weeks are going to be fun to watch. Link to comment Share on other sites More sharing options...
burgertime Posted January 5, 2011 Share Posted January 5, 2011 Agree, I'm not saying it wont happen that way just what usually happens. Usually as redevelopment takes place like shown on the DGEX it pulls what precip is west toward the core thus leaving I-85 and points west screwed. I'm not saying that is what will happen but what could happen.... again this is the DGEX we are talking about so I'm not worried. Yep the Christmas storm was a perfect example. We got 3-4 while everyone around us was in 5-8 . Hopefully if the DGEX is right we could squeeze more then 2-3 inches out of it. However I am not buying what the DGEX is selling, mainly just cause I'm a Link to comment Share on other sites More sharing options...
strongwxnc Posted January 5, 2011 Share Posted January 5, 2011 Does the DGEX have a wheel house? I mean, does it have a time frame that it scores good in? Yep the Christmas storm was a perfect example. We got 3-4 while everyone around us was in 5-8 . Hopefully if the DGEX is right we could squeeze more then 2-3 inches out of it. However I am not buying what the DGEX is selling, mainly just cause I'm a Link to comment Share on other sites More sharing options...
Poimen Posted January 5, 2011 Share Posted January 5, 2011 Does the DGEX have a wheel house? I mean, does it have a time frame that it scores good in? Probably not. What I find interesting about it's solution is two things. (1) I think it resembles something close to what HPC is talking about this morning. (2) If my memory is correct, I believe the 12Z EURO from Monday had a very similar solution. Link to comment Share on other sites More sharing options...
DaculaWeather Posted January 5, 2011 Share Posted January 5, 2011 Does the DGEX have a wheel house? I mean, does it have a time frame that it scores good in? I want to say it's two or three days but someone please correct me if I'm wrong. Link to comment Share on other sites More sharing options...
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