Stovepipe Posted January 27, 2014 Author Share Posted January 27, 2014 Its also catching the initial WAA precip I was worried about over N AL, N GA and even SERN TN...the signal is there on the NAM too but its very weak, I would not be surprised if there is a narrow band of snow breaking out as early as 8-9am for places like RMG, CHA, BHM and maybe ATL although believe it or not I could see them shafted between that WAA and then the main slug 12z RGEM snowfall Link to comment Share on other sites More sharing options...
tnweathernut Posted January 27, 2014 Share Posted January 27, 2014 This doesn't look terrible. I wasn't expecting more than virga or flurries, but this in house model looks like it could have been under the control of Robert Sent from my iPhone using Tapatalk Link to comment Share on other sites More sharing options...
Stovepipe Posted January 27, 2014 Author Share Posted January 27, 2014 Great googly moogly Robert! (Red emphasis mine) I don't think the models have a good handle on this at all. They continue to miss small, but important details, and in this pattern and setup, the details will mean everything. For starters, they missed the break-off upper low in Arizona. Now that will get sheared east soon but it 's important because it will maintain a continuous steady tap to the parent upper low and by 18 hours, you can see where RAP has it. It will bring a steady influx of vorts and even though the main parent probably never gets fully involved or picked, it probably doesn't have to. Because the whole setup is a great isentropic lifter. This is why the models have inched back west and north with time , recognizing the theory of how overrunning works. And in this case, it's a pretty interesting one because of so many factors and pieces at play. It's never easy in the Southeast. As the Montana wave dives strongly tomorrow early morn (see RAP), it will help the southern two waves to spread out energy, back the flow ever so slightly and moisture will break out quickly in probably two bands. One near the Gulf, and one further north, maybe Red River, Arkansas through TN. That one will be light but with time as the (by then) parent in the northern part of Mexico feeds into the digging Plains wave the whole axis backs nicely. And we've already seen what any RH field can do with cold air...look at TX, LA, MS recently with that weak event, and hardly any dynamics. So I think the models are blowing this badly. Moisture should begin to break out quickly maybe in two sections but by Tuesday night its joining as one from most of LA, and the southern and centra part of MS, then fanning northeast from middle TN, and southern VA and points in between. A pretty big chunk of Southeast real estate. And after that it's hard to say...still not trusting models verbatim here. But NAM looks ok at 5H and similar to what Euro had a couple or 3 days ago for this time frame, with a lot of energy that has slowed and deepened in the TN Valley, that keeps the moisture field going in southern, eastern Al, most of GA and most of the Carolinas but ending from west to east. The big winners in actual Qpf totals still should be southern Al, to middle and southern GA and much of SC, central and eastern NC and probably middle to eastern VA. But I'm questioning how much the models will be off further west because of the initial overrunning that usually starts before they think, and in this case has much more of a good tap going for it further west, especially considering how badly they are missing just 12 to 24 hours out. So trends, RAP and actual observations like the Water vapor are probably more important than assumming the GFS , NAM at 48 and 60 hours will be correct. I seriously doubt they are now, and you can tell something is wrong because of the subtle or even pretty stout changes run to run. Its about as a tight of a race between energy feeding into the northern stream, versus northern stream total dominance, as I can ever recall, so it's nearly impossible to make a forecast here, LOL. Some region is going to get a solid 8" snowfall out of this and honestly the way I think the 5H axis aligns and moisture continues to back build,and good upper jet location for areas east of Apps, from GA , I think much of SC, NC and southern to southeast VA stands a shot at a major snowfall by the time its over. And if the slow down trough happens in TN valley like I think, then eastern Carolinas are really in for a biggie, eastern VA as well...and many are going to get sleeted half to death (think south, middle GA to middle SC) plus some freezing rain.Don't be surprised to see major model swings, even this late. But I'm using synoptics theory to do my forcast .. There are good trends though if you're wanting snow back in eastern TN, much of Alabama and GA and western Carolinas though based on what I think will be much more overunning than any model shows. Here's a graphic to help explain the theory of what might happen. I hope your area gets snowed in, if that's what you're wanting. I see the NAM has zilch over me but the older I get the less I care for it. Too much hassle. Enjoy this fascinating Winter storm friends, and take care...watch out for some suprises..there will be some! robert Link to comment Share on other sites More sharing options...
Stovepipe Posted January 27, 2014 Author Share Posted January 27, 2014 UKMET precip hour 30, no clue on units: Link to comment Share on other sites More sharing options...
Stovepipe Posted January 27, 2014 Author Share Posted January 27, 2014 Weather Prediction Center: Link to comment Share on other sites More sharing options...
Stovepipe Posted January 27, 2014 Author Share Posted January 27, 2014 Another one of those local TV in house RPM models; Link to comment Share on other sites More sharing options...
Stovepipe Posted January 27, 2014 Author Share Posted January 27, 2014 12z GGEM snow hour 36 Link to comment Share on other sites More sharing options...
Chattownsnow Posted January 27, 2014 Share Posted January 27, 2014 I don't even really care what the models show at this point, just watch the sky and radar lol. not a single local meteorologist is mentioning even a possibility of flurries here so it really seems unlikely. but the models are still trying to figure this thing out so who knows. Link to comment Share on other sites More sharing options...
Stovepipe Posted January 27, 2014 Author Share Posted January 27, 2014 I don't even really care what the models show at this point, just watch the sky and radar lol. not a single local meteorologist is mentioning even a possibility of flurries here so it really seems unlikely. but the models are still trying to figure this thing out so who knows. WVLT here is calling for snow showers tomorrow morning. Based on everything I've seen, I think this is what we can expect from CHA to TYS to TRI: Expect nothing. Dusting - congrats, you made it through the virga with something to show for it. 1 inch - be very happy 2 inches or more - nekkid snow angel time because a miracle has happened. Link to comment Share on other sites More sharing options...
Blue Ridge Posted January 27, 2014 Share Posted January 27, 2014 This is beginning to remind me of a storm from 2010-2011. I'll dig and see if I can find the exact date. In short, a low that was otherwise far too south to affect us interacted with NS energy, resulting in a persistent band of light snow that lasted several hours. Link to comment Share on other sites More sharing options...
Stovepipe Posted January 27, 2014 Author Share Posted January 27, 2014 Water vapor porn http://www.daculaweather.com/4_nh_wv_loop.php Link to comment Share on other sites More sharing options...
Vol4Life Posted January 27, 2014 Share Posted January 27, 2014 NWS is now mentioning a slight chance of snow (30%) for tomorrow and tomorrow night for the Knoxville area. Earlier today, they were forecasting partly sunny conditions for tomorrow. Another 50-75 mile NW trend and those percentages will go up along with the probability of a little accumulating snow. Link to comment Share on other sites More sharing options...
Stovepipe Posted January 27, 2014 Author Share Posted January 27, 2014 18z Nam 24 hour snowfall hour 27 Link to comment Share on other sites More sharing options...
Stovepipe Posted January 27, 2014 Author Share Posted January 27, 2014 I'm amazed at how this has slowly trended over the past few days. If you had told me 4 days ago that east TN would have more snow than central NC with this thing I'd have said put down the crack pipe. Look at this hour 39: Granted it's the NAM but still.... Link to comment Share on other sites More sharing options...
tnmetalhead Posted January 27, 2014 Share Posted January 27, 2014 Pretty good discussion from MRX this afternoon... THE BIG QUESTION WITH THE FORECAST WAS THE AREA OF LIGHTPRECIPITATION THAT THE NAM AND NOW THE GFS AND ECMWF ARE SHOWINGALONG THE MOUNTAINS AND BRIEFLY OVER THE VALLEYS ON TUESDAY. GIVENTHE COLD AIR IN PLACE AND THE DEEP MOISTURE ASSOCIATED WITH THISWAVE...SOME ACCUMULATING SNOW WILL BE POSSIBLE /PRIMARILY OVER THEHIGHER TERRAIN/. AM THINKING THAT SOME OF THESE QPF SIGNALS/ESPECIALLY THE WIDESPREAD ONES OVER THE VALLEY/ AND A BIT OVERDONEAS THERE IS FAIRLY WEEK FRONTOGENESIS TAKING PLACE. HOWEVER...SOMEUPPER-LEVEL SUPPORT IS THERE WITH THE RIGHT ENTRANCE REGION OF THEJET ROTATING OVER THE REGION DURING THE AFTERNOON. THUS...INCREASEDPOPS FOR SOME LIGHT SNOW OVER THE VALLEYS AND SOME ACCUMULATINGSNOW OVER THE EAST TENNESSEE MOUNTAINS AND SOUTHWEST NORTH CAROLINADURING THE AFTERNOON. GIVEN THE UNCERTAINTY OF HOW WIDESPREAD THISACTIVITY WILL BE...HAVE BEEN CONSERVATIVE WITH SNOWFALL AMOUNTS. DOTHINK THAT PERHAPS AN INCH OR TWO WILL BE POSSIBLE ALONG THE HIGHMTNS GIVEN THE AVAILABLE MOISTURE AND HIGH RATIOS...WITH UP TO ADUSTING ELSEWHERE IN PARTS OF THE SURROUNDING VALLEYS AS A BULK OFTHE HEAVIEST PRECIPITATION WILL BE WELL TO THE SOUTH AND EAST. Link to comment Share on other sites More sharing options...
Stovepipe Posted January 27, 2014 Author Share Posted January 27, 2014 Pretty good discussion from MRX this afternoon... Welcome to the forum tnmetalhead! Link to comment Share on other sites More sharing options...
tnmetalhead Posted January 27, 2014 Share Posted January 27, 2014 I'm amazed at how this has slowly trended over the past few days. If you had told me 4 days ago that east TN would have more snow than central NC with this thing I'd have said put down the crack pipe. Look at this hour 39: Granted it's the NAM but still.... Wow, no kidding. Looks like a big chunk of Kentucky cashes in too. Link to comment Share on other sites More sharing options...
tnmetalhead Posted January 27, 2014 Share Posted January 27, 2014 Welcome to the forum tnmetalhead! Thank you sir! I was excited to see this new subforum! Link to comment Share on other sites More sharing options...
Reb Posted January 27, 2014 Share Posted January 27, 2014 Link to comment Share on other sites More sharing options...
bearman Posted January 27, 2014 Share Posted January 27, 2014 These kind of events are the most exciting even if nothing develops. I like surprises. The constant model watching and all the disappointments get old. It's great to get something sneak up on us. It is so rare these days Link to comment Share on other sites More sharing options...
Stovepipe Posted January 27, 2014 Author Share Posted January 27, 2014 These kind of events are the most exciting even if nothing develops. I like surprises. The constant model watching and all the disappointments get old. It's great to get something sneak up on us. It is so rare these days I hear you brother. Ultimately it's more fun to not be in the bullseye for days and then get a little surprise than the other way around. Gonna be a lot of disappointment over in the SE forum I'm afraid. Link to comment Share on other sites More sharing options...
tnmetalhead Posted January 27, 2014 Share Posted January 27, 2014 18z Hi Res NAM pretty generous to East TN Mtns. Link to comment Share on other sites More sharing options...
Stovepipe Posted January 27, 2014 Author Share Posted January 27, 2014 18z RGEM at hour 30: Keep in mind that all of these snow maps are 10:1 ratio. I'm hearing we might be able to push 12:1 or 15:1. The Cobb algorithm for the NAM added a full INCH to the verbatim snow total, bringing it to 2.1 inches for TYS. That was 12z, haven't seen the 18z Cobb output yet. Link to comment Share on other sites More sharing options...
Stovepipe Posted January 27, 2014 Author Share Posted January 27, 2014 RAP sim radar showing 20-30 dbz returns tomorrow morning. Still a pipe dream Reb? Link to comment Share on other sites More sharing options...
Chattownsnow Posted January 27, 2014 Share Posted January 27, 2014 Geez and I had pretty much given up on much of anything. Now I have to keep trolling the forums with these slight glimmers of hope lol. Link to comment Share on other sites More sharing options...
tnmetalhead Posted January 27, 2014 Share Posted January 27, 2014 The trends are definitely encouraging for East TN this afternoon. I honestly don't know what to expect...You're right though, ratios could be quite good If the dry air can be overcome! Link to comment Share on other sites More sharing options...
Tabbycat Posted January 27, 2014 Share Posted January 27, 2014 We might be on the right side of Knox county for a change, Stovepipe. I'd take 2" and be delighted, though I'm not messing it up with nekkid snow angels if it happens, lol. Link to comment Share on other sites More sharing options...
Stovepipe Posted January 27, 2014 Author Share Posted January 27, 2014 18z GFS hour 30 Link to comment Share on other sites More sharing options...
Stovepipe Posted January 27, 2014 Author Share Posted January 27, 2014 Robert just posted this on FB Thanks for all the new likes on this page. I'm so overwhelmed I can't answer all the PM's and emails though, but it's very much appreciated. This system is difficult, but it's never easy in the Southeast. I used a heavy dose of pattern recognition a few days ago when I saw the chance coming and the models are still playing catch-up. I have all my specific maps at the premium side, but I do put out custom maps here as well, and am working on one as we speak. The models aren't catching on to two things: 1) the amount of isentropic lifting from Texas, Red River and Tennessee Valley tonight and early Tuesday. 2) Not pulling enough energy off the top of the Baja/Mexico upper low, hence every run of RAP each hour increases the moisture output in that initial band, much as I ancticipated. 3) The models don't know what to do on Wednesday when the remnants of the Gulf upper low try to get handed off to a "shear axis" near the Tennessee Valley. Instead they sweep everything out to sea quickly, but that might be a big error in eastern Georgia, eastern Carolinas and eastern Virginia. 4) Overall moisture could still fill in much more than shown, but that's almost unknowable now, until the RAP model or the radar literally tells something different. Be on guard in the morning about anywhere from eastern TN, Alabama and all points east through Carolinas, Virginia, Georgia and eventually northern Florida. Yes, Florida Ice and Snow. Imagine! A dangerous ice storm for the SC low country and middle to south Georgia looks likely. Snow amounts are the trickiest to forecast. But much of NC, and VA, especially the further you go, are in fore sizeable snow. Atlanta, Charlotte, Raleigh, Richmond and Norfolk should measure decent snow with this event...Possibly over 6" in Raleigh and Norfolk. Link to comment Share on other sites More sharing options...
Vol Man Posted January 27, 2014 Share Posted January 27, 2014 Robert seems to be a little on an island with this one...but, he seems pretty sure about this developing over the TN Valley. Hopefully, we will be able to squeeze at least a little action out of this storm. Saturday morning surprised us....maybe tomorrow too. I will be watching the water vapor tonight...that always seems to be a good indicator this close in. Is there a specific area to watch for? Link to comment Share on other sites More sharing options...
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