eurojosh Posted November 25, 2014 Share Posted November 25, 2014 So when does NWS pull the trigger for DC metro? At least for WWA? Link to comment Share on other sites More sharing options...
yoda Posted November 25, 2014 Share Posted November 25, 2014 Looks to me that the sounding above 600mb is almost unstable at 15Z. Not sure what that means. Does that usually mean a chance of thundersnow Wes? Link to comment Share on other sites More sharing options...
usedtobe Posted November 25, 2014 Share Posted November 25, 2014 I think the NAM becomes more useful from here out. 24 hours out it should in theory have a decent handle on the lower levels. The cooling makes sense. I'd expect that a theme of the day. Theoretically, that's true though if it is overdoing precip it might be lowering the temps too much. Link to comment Share on other sites More sharing options...
usedtobe Posted November 25, 2014 Share Posted November 25, 2014 Does that usually mean a chance of thundersnow Wes? Good question, maybe though the soundinglooks a little different than most thundersnow soundings. Link to comment Share on other sites More sharing options...
Quasievil Posted November 25, 2014 Share Posted November 25, 2014 personally, I don't care if it's the NAM, the worst of them all, but it shows a trend that was also reflected on the 6z RGEM so in that regard, whether I believe the NAM verbatim, it shows a glimmer of hope that the next 18-24 hrs. will trend colder after most models warmed the preceding 24 hrs. Bluntly, I can't help but think that this is the normal Lucy and Charlie Brown with the football. These trends should be taken with a grain of salt, IMO. Link to comment Share on other sites More sharing options...
Bob Chill Posted November 25, 2014 Share Posted November 25, 2014 I think the NAM becomes more useful from here out. 24 hours out it should in theory have a decent handle on the lower levels. The cooling makes sense. I'd expect that a theme of the day. I agree. Nam always jumps around leading into large developing precip events. Once init data includes early stages of development it does much better. Maybe not qpf but certainly other things like vv's and thermals. Link to comment Share on other sites More sharing options...
Ian Posted November 25, 2014 Share Posted November 25, 2014 Theoretically, that's true though if it is overdoing precip it might be lowering the temps too much. The Euro has crushed us with precip for like 350 runs. If we don't get some heavy precip I'm never looking at it again. Of course getting it timed right and everything, but... Link to comment Share on other sites More sharing options...
Scarlet Pimpernel Posted November 25, 2014 Share Posted November 25, 2014 If gfs/euro tick better on temps there's going to be a lot of weenie backpedaling. I may bump a few just for some cheap thrills. My personal over/under is 4" but I may need to measure hourly to get there. We can hope the temps show an improvement like the NAM did. And I'm sure one would sacrifice weenie backpedaling if we get more snow than we thought before! Your over/under looks pretty reasonable for where you're at. I'm a bit closer in toward DC than you, so I might go with ~2" IMBY for that. And I may have to measure half-hourly! Link to comment Share on other sites More sharing options...
MN Transplant Posted November 25, 2014 Share Posted November 25, 2014 I don't have a great snow memory, how often do we actually do ok on snowfall after >0.5" of rain. I can't think of any recent ones off the top of my head. Link to comment Share on other sites More sharing options...
DDweatherman Posted November 25, 2014 Author Share Posted November 25, 2014 I don't have a great snow memory, how often do we actually do ok on snowfall after >0.5" of rain. I can't think of any recent ones off the top of my head. True, the second half of 1/26/11 after the morning stuff when areas changed to rain included some heavy rainfall before the changeover, but not sure how much that amounted to overall. Link to comment Share on other sites More sharing options...
Bob Chill Posted November 25, 2014 Share Posted November 25, 2014 I don't have a great snow memory, how often do we actually do ok on snowfall after >0.5" of rain. I can't think of any recent ones off the top of my head. Jan 11 comes to mind Link to comment Share on other sites More sharing options...
aldie 22 Posted November 25, 2014 Share Posted November 25, 2014 I don't have a great snow memory, how often do we actually do ok on snowfall after >0.5" of rain. I can't think of any recent ones off the top of my head. Obviously I prefer it to start as snow but it's pretty cool watching the driving rain start to changeover. Seems like about 8-10am is when that may happen at JYO... Link to comment Share on other sites More sharing options...
Scarlet Pimpernel Posted November 25, 2014 Share Posted November 25, 2014 I don't have a great snow memory, how often do we actually do ok on snowfall after >0.5" of rain. I can't think of any recent ones off the top of my head. Perhaps 1-26-2011 (Commutageddon)? Though we had snow very early in the day, a break in the precip, then heavy rain that was followed by sleet...then the amazing snow rates. Not sure if we got 0.5" rain before the change-over though. It was pretty darned wet before it switched to sleet/snow I recall, and no snow on the ground when that started (I ended up with 8"). Link to comment Share on other sites More sharing options...
WxUSAF Posted November 25, 2014 Share Posted November 25, 2014 I don't have a great snow memory, how often do we actually do ok on snowfall after >0.5" of rain. I can't think of any recent ones off the top of my head. Yeah, I was going to say 1-26-11 like other folks, but I think we got a respectable amount of rain between the WCB and ULL snows on Feb 13 this year. Both those storms were pretty similar in pattern (WCB snows, lull with rain, ULL snows), but quite different then what we're facing. Link to comment Share on other sites More sharing options...
Scarlet Pimpernel Posted November 25, 2014 Share Posted November 25, 2014 Yeah, I was going to say 1-26-11 like other folks, but I think we got a respectable amount of rain between the WCB and ULL snows on Feb 13 this year. Both those storms were pretty similar in pattern (WCB snows, lull with rain, ULL snows), but quite different then what we're facing. Feb. of this year was my other thought too. Though we had a good coating of snow already on the ground even with the rain and drizzle, it wasn't bare. Link to comment Share on other sites More sharing options...
real Posted November 25, 2014 Share Posted November 25, 2014 personally, I don't care if it's the NAM, the worst of them all, but it shows a trend that was also reflected on the 6z RGEM so in that regard, whether I believe the NAM verbatim, it shows a glimmer of hope that the next 18-24 hrs. will trend colder after most models warmed the preceding 24 hrs. Didn't all the models trend "colder" in hours before 3/5/13 and the bust last December. And the post Mortem of those were you shouldn't be fooled by last minute cooling trends when so many other factors suggest limits on snowfall in I-95 corridor? Link to comment Share on other sites More sharing options...
WxUSAF Posted November 25, 2014 Share Posted November 25, 2014 Feb. of this year was my other thought too. Though we had a good coating of snow already on the ground even with the rain and drizzle, it wasn't bare. I had about 14" from the WCB on the ground in the morning and then it melted/compacted with the rain, but was far from bare when the ULL snows kicked in. Link to comment Share on other sites More sharing options...
Bob Chill Posted November 25, 2014 Share Posted November 25, 2014 Didn't all the models trend "colder" in hours before 3/5/13 and the bust last December. And the post Mortem of those were you shouldn't be fooled by last minute cooling trends when so many other factors suggest limits on snowfall in I-95 corridor?Temps busted with the march storm because rates and dynamics never materialized. Early on it snowed nicely before the plug suddenly got yanked from the wall.If this storm fizzles from guidance the same thing will happen. But it's a very different type of storm either way Link to comment Share on other sites More sharing options...
DDweatherman Posted November 25, 2014 Author Share Posted November 25, 2014 I had about 14" from the WCB on the ground in the morning and then it melted/compacted with the rain, but was far from bare when the ULL snows kicked in. I had 11 from it and had 6ish left in Dundalk before 3 additional inches from the ULL. Link to comment Share on other sites More sharing options...
Scarlet Pimpernel Posted November 25, 2014 Share Posted November 25, 2014 I had about 14" from the WCB on the ground in the morning and then it melted/compacted with the rain, but was far from bare when the ULL snows kicked in. Same here...I had 12" before the rain, still had a heavy covering (though compacted a lot) by the time the ULL snow came in. I only got ~2" additional from that, but it came down really hard for awhile. Link to comment Share on other sites More sharing options...
Heisy Posted November 25, 2014 Share Posted November 25, 2014 For us in Philly Feb 5 2001 was a heavy rain to back end whiteout.... Link to comment Share on other sites More sharing options...
H2O Posted November 25, 2014 Share Posted November 25, 2014 Didn't all the models trend "colder" in hours before 3/5/13 and the bust last December. And the post Mortem of those were you shouldn't be fooled by last minute cooling trends when so many other factors suggest limits on snowfall in I-95 corridor? agree. when we have to rely on the storm to generate the cold it can occur that the models overdo temps. and many areas never see the forecast temps needed to get the glorious changeover or sustainable rates Link to comment Share on other sites More sharing options...
MN Transplant Posted November 25, 2014 Share Posted November 25, 2014 Jan 2011 had excellent dynamics which aren't present with this storm, unfortunately. Link to comment Share on other sites More sharing options...
Ian Posted November 25, 2014 Share Posted November 25, 2014 I wouldn't be surprised if a lot of people west of 95 don't see much pure rain. I mean white rain is the same I guess, though I'd hedge snowy. Busts teach lessons but you should focus on the current situation more than busts when it comes to thinking up what will happen. Link to comment Share on other sites More sharing options...
DDweatherman Posted November 25, 2014 Author Share Posted November 25, 2014 Why I like this more than 3/6: The dynamics are more widespread and are not as in dire need for everywhere as 3/6, though its close. -We have a better sun angle overall and respectively -The euro has been modeling intense precip in the region that could be convective in nature -This storm is taking a textbook snowstorm track if cold air were to be present -The column/skew-t's are solid above 950, and we are not depending on an isothermal sounding. Link to comment Share on other sites More sharing options...
usedtobe Posted November 25, 2014 Share Posted November 25, 2014 Yeah, I was going to say 1-26-11 like other folks, but I think we got a respectable amount of rain between the WCB and ULL snows on Feb 13 this year. Both those storms were pretty similar in pattern (WCB snows, lull with rain, ULL snows), but quite different then what we're facing. But both of those lows had closed upper lows with them if I remember right. As you note, the set upp was much different for those storms than this one. Link to comment Share on other sites More sharing options...
Scarlet Pimpernel Posted November 25, 2014 Share Posted November 25, 2014 Temps busted because rates and dynamics never materialized. Early on it snowed nicely before the plug suddenly got yanked from the wall. If this storm fizzles from guidance the same thing will happen. But it's a very different type of storm either way I remember the same exact thing. Early in the morning there was some snow on the ground and for a time it was coming down nicely. Then literally wham! that was it other than a few popcorn snow showers the rest of the day in amongst a mix of white rain/snow. Dynamics stayed to our south as I recall, RIC and surrounding areas scored big on the ULL while we got little to nothing. Link to comment Share on other sites More sharing options...
DDweatherman Posted November 25, 2014 Author Share Posted November 25, 2014 I really do like our current Dews with regard to where they are projected to be. A little glimmer of hope possibly. Link to comment Share on other sites More sharing options...
mitchnick Posted November 25, 2014 Share Posted November 25, 2014 personally, there is nothing more satisfying to this weenie than witnessing rain changing to heavy, accumulating snow likewise, there nothing more demoralizing than to wait for changeovers that either never occur or occur too late to accumulate snow since elevation will be a big consideration, for those who are interested I suggest 2 sites the top one allows you to input your address and it states your exact elevation and the bottom one is a NWS product that lets you zoom in to get a very good idea of elevations that are displayed on the bottom right of the page http://veloroutes.org/elevation/ http://preview.weather.gov/edd/?lat=40.329452873812926&lon=-75.73059082031124&zoom=6&ql=FFFFFFTFFFFFFFFFFFFFFFFFF&ml=&bm=Google_Terrain&lsr=F&lfc=F&rt=obs&rf=major|moderate|minor|action&ht=F&pid=N0Q&sf=GOES_Infrared&ri=15&obs=TFTTFFFFFFTFFFFT&is=1&ou=mph&od=-50&ships=F&cluster=T&radO=0.75&satO=0.75&hazO=0.55&tropO=0.7&ndfdO=0.7&ndfdR=Continental_US&ndfdF=Maximum_Temperature_%28%C2%BAF%29&ndfdT=12&ndfdTS=&f100=F&lviz=F&fullscreen=F&fxt=Point_%28Text_Only%29&ppd=24&pdy=3&satf=60&obsync=F&owv=F&flavor=Advanced&tfo=&tfd=&tfw=null&ht=F&hd=F&ho=null&hf=null&hb=F&ot=Meteorological_Observation&hvt=F&sht=T&uwl=F Link to comment Share on other sites More sharing options...
T. August Posted November 25, 2014 Share Posted November 25, 2014 Early Feb. this year I got over an inch of rain I believe, then it switched to snow. .5" of snow on grass. Different situation entirely, but it can happen. Link to comment Share on other sites More sharing options...
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