cae Posted March 15, 2014 Share Posted March 15, 2014 Wow, big difference for Towson on the 18z NAM. I was wrong earlier about the 12z NAM -- the 4 mm I saw was for the second wave at the end of the run, and there was nothing from the first wave. In the 18z NAM, we get 16 mm from the first wave, and another 48mm (and still going at 84) on the second wave. Yes, it's the NAM at 84, but fwiw the second wave is a borderline ice storm verbatim (surface at freezing) with 850 temps crashing below freezing near the end. Link to comment Share on other sites More sharing options...
Scarlet Pimpernel Posted March 15, 2014 Share Posted March 15, 2014 The prime difference with the 18z nam and the globals is the 850 low is more organized with better circulation. The n-nw side of the shield is simply more juiced with a banded structure. Euro is kinda weak and strung out in comparison. GFS is more of a middle ground between them. The nam is "supposed" to be a better model at picking up on things like this at short leads because of its resolution. We'll see how things go tonight and tomorrow. I'm not willing to discount the nam just because it's an outlier. Even though the totals seem quite unlikely, the better expanse and banded nature of the precip is believable. I kinda feel the same way zwyts does. The possibility of a better organized system has just presented itself. But until it has support, favoring it is a big mistake. You know, as I was looking at the 850-mb earlier along with the other levels, I was thinking to myself that the circulation at 850 was mighty nice compared to before. There's good inflow coming right into the area off the Atlantic, as well as the classic CAD signature. Link to comment Share on other sites More sharing options...
Heisy Posted March 15, 2014 Share Posted March 15, 2014 Well this looks funkyhttp://www.instantweathermaps.com/NAM-php/showmap-conusncep.php?run=2014031518&var=PCPPRSTMP_850mb&hour=084 Dynamic cooling, lol...goes to show you how ****ty the NAM is in the LR, not like we didn't know though. Link to comment Share on other sites More sharing options...
Bob Chill Posted March 15, 2014 Share Posted March 15, 2014 You know, as I was looking at the 850-mb earlier along with the other levels, I was thinking to myself that the circulation at 850 was mighty nice compared to before. There's good inflow coming right into the area off the Atlantic, as well as the classic CAD signature. After taking a second look I'm not sure if its really that now. The lp is further north than 12z. H5 is just a bit more amped in front with a bit of relaxation from the wall above us. The lp is only modestly more organized but the track is better. I think that combo of slight differences made for a much improved solution. Link to comment Share on other sites More sharing options...
T. August Posted March 15, 2014 Share Posted March 15, 2014 Several brush fires in Carroll County this afternoon. Had one impinge on a house and actually caught it on fire. There was one in Harford County too. Link to comment Share on other sites More sharing options...
snowfan Posted March 15, 2014 Share Posted March 15, 2014 Hi res NAM is out of control. The airports are in a nice 6-8/6-9" swath. Link to comment Share on other sites More sharing options...
Deck Pic Posted March 15, 2014 Share Posted March 15, 2014 the last time DC got 4" this late in the season was 1964 Link to comment Share on other sites More sharing options...
snowdude Posted March 15, 2014 Share Posted March 15, 2014 the last time DC got 4" this late in the season was 1964 When was the last time the heat island DCA recorded 4 inches of snow in a storm? *saracasm* Link to comment Share on other sites More sharing options...
ers-wxman1 Posted March 15, 2014 Share Posted March 15, 2014 Fantasy land NAM at 84hr would be a moderate to major coastal flood issue on top of the rain and snow melt with freshwater issues! Hope for sure it's wrong. Link to comment Share on other sites More sharing options...
wxmeddler Posted March 15, 2014 Share Posted March 15, 2014 The back end dynamic cooling is all Sleet, there is a warm layer at 750mb but verbaitm its gusting 30 kts out of the NE and sleet. Link to comment Share on other sites More sharing options...
Scarlet Pimpernel Posted March 15, 2014 Share Posted March 15, 2014 Fantasy land NAM at 84hr would be a moderate to major coastal flood issue on top of the rain and snow melt with freshwater issues! Hope for sure it's wrong. Funny thing is, if it were not all that much colder, it would be an unreal heavy wet snow! But unfortunately the cold air at the surface and mid-levels has retreated by that point. Actually the Shenandoah would get some good snow at least for awhile as depicted (from what I could see). It is fantasy land, but I hope that solution verbatim is nowhere near what happens. I know it's March, but it would be nice to keep the snow we do get for a little while rather than washing it away in a deluge almost right after the last flake falls! Link to comment Share on other sites More sharing options...
Scarlet Pimpernel Posted March 15, 2014 Share Posted March 15, 2014 The back end dynamic cooling is all Sleet, there is a warm layer at 750mb but verbaitm its gusting 30 kts out of the NE and sleet. Yeah, for S. PA it would be quite the funky solution!! I didn't look much at the different levels, but sleet with high winds would be...well...not a common experience! Link to comment Share on other sites More sharing options...
Deck Pic Posted March 15, 2014 Share Posted March 15, 2014 When was the last time the heat island DCA recorded 4 inches of snow in a storm? *saracasm* less than 2 weeks ago (3.8) Link to comment Share on other sites More sharing options...
nj2va Posted March 15, 2014 Share Posted March 15, 2014 18Z RGEM total precip: Link to comment Share on other sites More sharing options...
yoda Posted March 15, 2014 Share Posted March 15, 2014 18z RGEM ~14mm or so at DCA using image above Link to comment Share on other sites More sharing options...
WxMan1 Posted March 15, 2014 Share Posted March 15, 2014 Even this time yesterday I was thinking 2-4" type range for the metro region, 3-6" tops. But, I will say, for those worried about what was a drying trend on the north end of the EC and NAM...how did that drier solution work out along I-70 during the last event? It's awfully hard to comprehend the moisture an ULL plume in a little over 24 hours away passing too far to our south (low-mid level fgen too suppressed), when we're sitting close ro 70F today. My latest thoughts for DC I'm dubious of what can stick here in DC before around 3-4z....and after 15z....here is latest approx QPF in the 3z to 15z period 12z Euro: 0.3" 12z Canadian: 0.4" 12z GFS: 0.35" 18z NAM: 0.75" Until the NAM has more support, for now I'd probably toss it and lean toward 0.4".....will use 8:1 ratios to balance the fact that it may be a lower ratio event even when snowing and 32 or under, account for antecedent conditions and climo, the fact that we may not get much accumulation toward the beginning and end of that window, AND to account for the possibility of some minor accumulation before and after the window (particularly after when we "could finish with a heavy burst a la 3/3). I think 2-4" is the right forecast at this time for DC proper. Link to comment Share on other sites More sharing options...
aldie 22 Posted March 15, 2014 Share Posted March 15, 2014 For Ian...the back half of the NAM for jyo is over an inch of freezy rain...I'm assuming all of that accumulates Link to comment Share on other sites More sharing options...
EasternUSWX Posted March 15, 2014 Share Posted March 15, 2014 GFS pretty much holds suit. Link to comment Share on other sites More sharing options...
SomeguyfromTakomaPark Posted March 15, 2014 Share Posted March 15, 2014 GFS pretty much holds suit. Yep looks great, 0.6-0.7 by 15z Link to comment Share on other sites More sharing options...
ers-wxman1 Posted March 15, 2014 Share Posted March 15, 2014 Solid GFS run, 0.50-1.0 area wide Link to comment Share on other sites More sharing options...
Deck Pic Posted March 15, 2014 Share Posted March 15, 2014 Solid GFS run, 0.50-1.0 area wide problem for DC is ~0.4" falls by midnight...maybe 0.35" after that...No reason to take it too seriously...it did this on 1/21.... Link to comment Share on other sites More sharing options...
Bob Chill Posted March 15, 2014 Share Posted March 15, 2014 problem for DC is ~0.4" falls by midnight...maybe 0.35" after that...No reason to take it too seriously...it did this on 1/21.... Yep, 2-4 inside the beltway and 3-6 outside seems solid still. Link to comment Share on other sites More sharing options...
MacintoshPro Posted March 15, 2014 Share Posted March 15, 2014 Wow, thats a powerful system! http://radar.weather.gov/ridge/Conus/full_loop.php Link to comment Share on other sites More sharing options...
SomeguyfromTakomaPark Posted March 15, 2014 Share Posted March 15, 2014 Yep, 2-4 inside the beltway and 3-6 outside seems solid still. Soundings are good to go at 00z, maybe this time it's right and we do a little better. Link to comment Share on other sites More sharing options...
Bob Chill Posted March 15, 2014 Share Posted March 15, 2014 Soundings are good to go at 00z, maybe this time it's right and we do a little better.Maybe but it seems like they are always to quick at the surface. I would think 11pm or even midnight for dc to get to 32. Prob 10pm for me. Euro was much warmer but also weaker and strung out with the precip. Im sure that played a role. Would be awesome if the best rates held off until the surface gets right. We don't have a big cushion to waste to get to 4". Link to comment Share on other sites More sharing options...
kurtstack Posted March 15, 2014 Share Posted March 15, 2014 If the CWG 1-4" forecast is gonna bust,it's definitely going to bust on the high side of that envelope it would appear. Link to comment Share on other sites More sharing options...
Bob Chill Posted March 15, 2014 Share Posted March 15, 2014 One of the wildcards is the potential banded nature of the shield. Could be some mod/heavy for a time over some areas. Nowcasting will be fun. Link to comment Share on other sites More sharing options...
MacintoshPro Posted March 15, 2014 Share Posted March 15, 2014 If the CWG 1-4" forecast is gonna bust,it's definitely going to bust on the high side of that envelope it would appear. I think it may be a little low, especially after the latest GFS and NAM. The GFS has been very consistent today, so I think that maybe 3-6" is a better call, with locally higher amounts where highest banding materializes. Link to comment Share on other sites More sharing options...
aldie 22 Posted March 15, 2014 Share Posted March 15, 2014 One of the wildcards is the potential banded nature of the shield. Could be some mod/heavy for a time over some areas. Nowcasting will be fun. You called? Link to comment Share on other sites More sharing options...
Ian Posted March 15, 2014 Share Posted March 15, 2014 For Ian...the back half of the NAM for jyo is over an inch of freezy rain...I'm assuming all of that accumulatesTalking about that low is about as stupid as this forum gets. Link to comment Share on other sites More sharing options...
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