Ger Posted March 15, 2014 Share Posted March 15, 2014 When does the 12z GGEM initialize? Link to comment Share on other sites More sharing options...
Scarlet Pimpernel Posted March 15, 2014 Share Posted March 15, 2014 it's usually pretty smart to take an ensemble range of start/stop time -- find a 15 hour duration then divide the mean qpf by 15 hours because you know it's probably going to have a linear precip rate over those 15 hours Now that's pretty funny... So...rough math suggests DCA gets 0.5" snow an hour for 15 hours per SREF. So what accumulates will be the hours without March high sun angle. I do believe chris87 was being a bit sarcastic, not serious, with the "linear precip rate" comment! Well, I think so anyhow! Link to comment Share on other sites More sharing options...
WxMan1 Posted March 15, 2014 Share Posted March 15, 2014 The NAM did nudge the .25 and .50 contours a little farther north compared to the 06Z, with the .01 just south of the Mason/Dixon line. However, I wouldn't look at the 4km high-res NAM (Conest). As one would expect, an even tighter gradient on the northern fringe, as in 0.0 for northern Mo. County. I will say it again, outside of the .30 to .40" of QPF that was wasted away to rain/sleet, and the fact that the event will be more of a late evening/overnight/early AM one instead of pre-dawn to early afternoon one, the concerns here are remarkably similar to that of 03/03.. Link to comment Share on other sites More sharing options...
WxMan1 Posted March 15, 2014 Share Posted March 15, 2014 12Z RGEM: about 10 mm (~0.4") for DCA through 12Z Monday. Link to comment Share on other sites More sharing options...
Scarlet Pimpernel Posted March 15, 2014 Share Posted March 15, 2014 The NAM did nudge the .25 and .50 contours a little farther north compared to the 06Z, with the .01 just south of the Mason/Dixon line. However, I wouldn't look at the 4km high-res NAM (Conest). As one would expect, an even tighter gradient on the northern fringe, as in 0.0 for northern Mo. County. I will say it again, outside of the .30 to .40" of QPF that was wasted away to rain/sleet, and the fact that the event will be more of a late evening/overnight/early AM one instead of pre-dawn to early afternoon one, the concerns here are remarkably similar to that of 03/03.. Pretty much. Who would have thought that in March, we'd be nervous about too much of a cold air push suppressing precip too far south! For two events, no less. Link to comment Share on other sites More sharing options...
winterymix Posted March 15, 2014 Share Posted March 15, 2014 Now that's pretty funny... I do believe chris87 was being a bit sarcastic, not serious, with the "linear precip rate" comment! Well, I think so anyhow! Yeah, i see that but the precip rate will probably be fairly linear, the important point being that accumulation may be very limited during daylight hours due to light intensity. Link to comment Share on other sites More sharing options...
yoda Posted March 15, 2014 Share Posted March 15, 2014 Just for reference, didn't we all complain about the NAM on the 3/3 storm... then cheer when the 0z run that night finally get a clue? I know NAM was off a bit on snow accums, but NAM did come north at the last min on that storm... just the dry cold air ate alot of our snow Link to comment Share on other sites More sharing options...
Bob Chill Posted March 15, 2014 Share Posted March 15, 2014 this airmass is definitely less impressive if still impressive. the NAM does a good job modeling the sharpness of an edge which is perhaps legit but location is another story. It just seems too tight. You go from .50 to nothing in 30 miles. High res has a gradient so tight that you go from 1" to zero in 60 miles. I would expect the lighter amounts away from where the jackpot is to be spread further north with broader contours. I may not know what the heck I'm talking about but it doesn't seem probable with this setup. Link to comment Share on other sites More sharing options...
yoda Posted March 15, 2014 Share Posted March 15, 2014 Through 24... looks like GFS will hold or nudge ever so slightly south on the SLP maps... but less QPF on the northern side comparing to 06z GFS Link to comment Share on other sites More sharing options...
gymengineer Posted March 15, 2014 Share Posted March 15, 2014 12Z RGEM: about 10 mm (~0.4") for DCA through 12Z Monday. And about 0.2" to the M/D line. Link to comment Share on other sites More sharing options...
yoda Posted March 15, 2014 Share Posted March 15, 2014 DCA/NE VA/S MD jackpot at 39 with 0.25 QPF... Link to comment Share on other sites More sharing options...
stormtracker Posted March 15, 2014 Author Share Posted March 15, 2014 snow by 8 per GFS....interesting enough, the GFS sounding for 5pm is snow as well. Link to comment Share on other sites More sharing options...
SomeguyfromTakomaPark Posted March 15, 2014 Share Posted March 15, 2014 A little drier on the northern edge (m/d line) initially but no gigantic shifts here. This solution would be great for everyone. Link to comment Share on other sites More sharing options...
stormtracker Posted March 15, 2014 Author Share Posted March 15, 2014 GFS is pretty nice Link to comment Share on other sites More sharing options...
T. August Posted March 15, 2014 Share Posted March 15, 2014 GFS is pretty nice Agreed. It gives us northerners some hope lol. Link to comment Share on other sites More sharing options...
MacintoshPro Posted March 15, 2014 Share Posted March 15, 2014 GFS boldly defies Euro and NAM, shows bullseye around DC and n/w. Link to comment Share on other sites More sharing options...
Bob Chill Posted March 15, 2014 Share Posted March 15, 2014 nice dc-bwi corridor .5-.6 through 2am eta: .6-.7 fairfax/loudon Solid run for sure Link to comment Share on other sites More sharing options...
Ian Posted March 15, 2014 Share Posted March 15, 2014 From worst model of them all back to favored status. Good for you goofus. Link to comment Share on other sites More sharing options...
chris87 Posted March 15, 2014 Share Posted March 15, 2014 The SREF and 12z NAM support each other although the NAM shows the south trend and therefore the SREF is overdoing north of DCA. Tell me how I busted Tuesday. so your forecast is 0.5 qpf at DCA with no accumulation -- i can't speak for everyone, but i'll give you that and hold you to it! Link to comment Share on other sites More sharing options...
midatlanticweather Posted March 15, 2014 Share Posted March 15, 2014 It just seems too tight. You go from .50 to nothing in 30 miles. High res has a gradient so tight that you go from 1" to zero in 60 miles. I would expect the lighter amounts away from where the jackpot is to be spread further north with broader contours. I may not know what the heck I'm talking about but it doesn't seem probable with this setup. Bob, the system last week that hit NC was super juicy at the NC/VA line, but it did not make it very far north at all.. it hit a dry HP that just killed northward movement and ate any precip headed this way. I think we have the same scenario. on 3/3 the HP was pressing as the precip arrived.. maybe I am wrong, but I think the HP is outpacing the moisture this time and thus we are missing whatever bit we got last time... If I lived in SC I would watch out (LOL) - just thinking of how far south that system went from NY to below us last time! Link to comment Share on other sites More sharing options...
Bob Chill Posted March 15, 2014 Share Posted March 15, 2014 From worst model of them all back to favored status. Good for you goofus. I like the gfs overall. Not a bad panel through 8am: Link to comment Share on other sites More sharing options...
midatlanticweather Posted March 15, 2014 Share Posted March 15, 2014 Wasn't the same story being played out on 3/3? GFS was always better than every other model? Not trying to be a downer, but I am fairly certain that was the case! Link to comment Share on other sites More sharing options...
SomeguyfromTakomaPark Posted March 15, 2014 Share Posted March 15, 2014 I like the gfs overall. Not a bad panel through 8am: gfspaddyprecip.JPG Beautiful: 4-7 inches overnight Sunday. Just this one time GFS!!!! Be right. Link to comment Share on other sites More sharing options...
Bob Chill Posted March 15, 2014 Share Posted March 15, 2014 Bob, the system last week that hit NC was super juicy at the NC/VA line, but it did not make it very far north at all.. it hit a dry HP that just killed northward movement and ate any precip headed this way. I think we have the same scenario. on 3/3 the HP was pressing as the precip arrived.. maybe I am wrong, but I think the HP is outpacing the moisture this time and thus we are missing whatever bit we got last time... If I lived in SC I would watch out (LOL) - just thinking of how far south that system went from NY to below us last time! That's a bad comparison. Last week was a cutoff. If you weren't near the ull then you got nothing (as expected). This system is completely different with a plume of waa far out in front of the slp/850 low. Link to comment Share on other sites More sharing options...
WxMan1 Posted March 15, 2014 Share Posted March 15, 2014 GFS very consistent QPF-wise, at least through 18Z Monday. 06Z run was a tad under .75" for DCA through 18Z Mon, the 12Z GFS is a tad higher, closer to 0.80". The bulk of which is through 12Z. GFS is very similar with the amounts around the M-D line. Link to comment Share on other sites More sharing options...
winterymix Posted March 15, 2014 Share Posted March 15, 2014 so your forecast is 0.5 qpf at DCA with no accumulation -- i can't speak for everyone, but i'll give you that and hold you to it! My impression is for accumulation around DCA but not after about 9 am or 10 am unless the rates are moderate. Light daytime snow isn't going to accumulate around DCA in mid-March on south-facing sidewalks and on most street surfaces; grass and shady areas, maybe so. Late night, no problem. Anyhow, the 12Z NAM gives me 3" to 5" in N MD with 8:1 ratios. Link to comment Share on other sites More sharing options...
yoda Posted March 15, 2014 Share Posted March 15, 2014 Got to say LWX is going to have a really hard time with issuing WWAs... or even WSW's... I guess you could blanket WWA's and then upgrade to WSW's once event gets going and you have a better handle on what radar is doing and showing Link to comment Share on other sites More sharing options...
chris87 Posted March 15, 2014 Share Posted March 15, 2014 NAM 0" here and GFS 5-7". 36hrs out. Good old models. sure for your discrete point -- what do you expect out of models? this is an extremely tight gradient -- i'm sorry you're on the edge of it -- the current 12z guidance that has come out are all in an expected range of uncertainty for the current lead time Link to comment Share on other sites More sharing options...
midatlanticweather Posted March 15, 2014 Share Posted March 15, 2014 That's a bad comparison. Last week was a cutoff. If you weren't near the ull then you got nothing (as expected). This system is completely different with a plume of waa far out in front of the slp/850 low. good points! Thanks! Link to comment Share on other sites More sharing options...
EasternUSWX Posted March 15, 2014 Share Posted March 15, 2014 sure for your discrete point -- what do you expect out of models? this is an extremely tight gradient -- i'm sorry you're on the edge of it -- the current 12z guidance that has come out are all in an expected range of uncertainty for the current lead time What do I expect? I expect some consistency. Model went from being near NY with snow to now barely scrapping PA in like 24hrs. Also 36hrs away from an event would think maybe we have a clue what might happen. Link to comment Share on other sites More sharing options...
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