SnowGoose69 Posted January 17, 2013 Share Posted January 17, 2013 The snow with the upper low over Mississippi is quite a bit north right now of where it was modeled by the 00Z NAM...this may very well have zero impact downstream...but right now JAN is basically being dry slotted while SWRN TN and NRN MS are getting snow in places that looked like they'd be too far north. Link to comment Share on other sites More sharing options...
Avdave Posted January 17, 2013 Share Posted January 17, 2013 Yeah I dont think it's game over. Look like lot of energy getting going down south. LOL Link to comment Share on other sites More sharing options...
Herb@MAWS Posted January 17, 2013 Share Posted January 17, 2013 Well this is more of an obs/nowcasting post but since there is no thread for that yet I'll post it here. The 6 hr sim radar panel of the 6z nam is pretty close to what I'm looking at on the real radar. The 9 hr panel shows the northern edge of the precip dip south and then at 12 and 15 comes back north a little and sits just south of DC metro. Still too close for me to write this one off. If that northern edge is 50 miles north we could be in business. I was thinking the same thing. The past 2 years, we saw a lot examples of "the N-ward Trend" which always seemed to bring S-ern New England back into the game even when they were earlier thought to be out of a main snow threat area. So, maybe it's our turn in Central MD/NOVA to benefit from one of these N-ward trends. Part wishcasting and maybe partly radar hallucinating. Link to comment Share on other sites More sharing options...
Fozz Posted January 17, 2013 Share Posted January 17, 2013 So, maybe it's our turn in Central MD/NOVA to benefit from one of these N-ward trends. Part wishcasting and maybe partly radar hallucinating. We did.......in January 2010 Link to comment Share on other sites More sharing options...
usedtobe Posted January 17, 2013 Share Posted January 17, 2013 I was thinking the same thing. The past 2 years, we saw a lot examples of "the N-ward Trend" which always seemed to bring S-ern New England back into the game even when they were earlier thought to be out of a main snow threat area. So, maybe it's our turn in Central MD/NOVA to benefit from one of these N-ward trends. Part wishcasting and maybe partly radar hallucinating. The trouble is that we're 41 degrees and the models have the boundary layer staying in the upper 30s durinng the bulk of the storm/day so even if we get the QPF, it might not matter unless it is really heavy which could help lower the temps. Lots of factors are working against the storm. Link to comment Share on other sites More sharing options...
SomeguyfromTakomaPark Posted January 17, 2013 Share Posted January 17, 2013 I was thinking the same thing. The past 2 years, we saw a lot examples of "the N-ward Trend" which always seemed to bring S-ern New England back into the game even when they were earlier thought to be out of a main snow threat area. So, maybe it's our turn in Central MD/NOVA to benefit from one of these N-ward trends. Part wishcasting and maybe partly radar hallucinating. The complete lack of precip blossoming anywhere above that northern edge isn't encouraging, however like I said, it's literally 20-40 miles south of DC. Too close not to keep a close eye on. Link to comment Share on other sites More sharing options...
snowfan Posted January 17, 2013 Share Posted January 17, 2013 Far too warm to get any meaningful accums prior to sunset. QPF is being wasted. Link to comment Share on other sites More sharing options...
usedtobe Posted January 17, 2013 Share Posted January 17, 2013 Far too warm to get any meaningful accums prior to sunset. QPF is being wasted. Exactly though I can hear a few sleet pllets with my 41 degree temps. Link to comment Share on other sites More sharing options...
WxMan1 Posted January 17, 2013 Share Posted January 17, 2013 Something to think about for those toward the north (DC area): The latest RAP continues to nudge some accumulating pcpn farther north into DC. By 03Z the RAP has about 0.10" of 6 hourly pcpn into DC while the other models remain dry. As you know, any pcpn before 21-00Z will basically be wasted; i.e. we'll get nothing from the WWA side of this system (not surprising to you I'm sure). Looking at some of the cross sections of moisture/omega/temps, as well as 700-500 mb theta-e lapse rates, it would seem that we could certainly see a narrow band of steadier pcpn (snow) this evening well north of the main widespread pcpn. You've seen this before: a band of snow well north of the main action, surrounded on either side by next-to-nothing, due in large part to the fact that even though the low levels aren't as moist as farther south, because of where the fgen/omega/moisture zone is (farther aloft compared to the south), it just so happens to be within the -12 to -18C layer, which would optimize the dendritic growth potential. Exactly *Where* any northern band sets up is still an unknown, but my hunch is it would be quite close if not within the DC metro area, perhaps bisecting EZF, likely in a SW-NE fashion. Certainly not as heavy compared to the main action farther south, but certainly "locally" higher than amounts on either side. Both the NAM and the GFS hint at this, with a northern axis of snow, with little/none just to the south of this axis, then the main snow area south of that. Link to comment Share on other sites More sharing options...
yoda Posted January 17, 2013 Share Posted January 17, 2013 Well, um, 09z SREFs says 0.25 QPF into DC and 0.5 into EZF... yeah... Link to comment Share on other sites More sharing options...
southmdwatcher Posted January 17, 2013 Share Posted January 17, 2013 We had a 10 minute period of moderate rain and sleet around 45 minutes ago just south of Waldorf, looks like a NC storm today.......I like Yoda's post^^^^^^^ north trend commence. Link to comment Share on other sites More sharing options...
WinterWxLuvr Posted January 17, 2013 Share Posted January 17, 2013 It ain't gonna help me, but the storm seems to be coming along nicely. Bet somebody gets thumped Link to comment Share on other sites More sharing options...
WxMan1 Posted January 17, 2013 Share Posted January 17, 2013 Far too warm to get any meaningful accums prior to sunset. QPF is being wasted. Yep. It's ALL about the back-side deformation/frontogenetic axis. The models show the best elevated TROWAL staying south of us in the DC area. For central and southern VA, it's a tricky forecast, because while it may be bloody warm for a while (i.e. all day), if/should they get underneath that favorable deformation zone, pcpn rates would really pick up and column cooling could quickly drop 37-39 down to 32-34 and S or S+. So for the coastal plain to our south, I still don't have a problem with the 3-6" forecast. It's just going to have to fall within a 6 hour window, something like 22-04Z or 00-06Z, but the conceptual model certainly suggests that could certainly be the case (1/2 inch to inch per hour rates for 4-6 hours). Link to comment Share on other sites More sharing options...
WxMan1 Posted January 17, 2013 Share Posted January 17, 2013 Well, um, 09z SREFs says 0.25 QPF into DC and 0.5 into EZF... yeah... What really matters is not the 24 hr QPF from 12Z today through 12Z tomorrow...but more like a 12hr fcst from 21Z through 09Z. All the qpf before 21-00Z today will be in liquid form... Link to comment Share on other sites More sharing options...
yoda Posted January 17, 2013 Share Posted January 17, 2013 well... if we still follow the models any... 12z NAM finally tosses us in DC a bone... but is it too late? Link to comment Share on other sites More sharing options...
MN Transplant Posted January 17, 2013 Share Posted January 17, 2013 What really matters is not the 24 hr QPF from 12Z today through 12Z tomorrow...but more like a 12hr fcst from 21Z through 09Z. All the qpf before 21-00Z today will be in liquid form... Both the 12z NAM and 12z RAP shut off any precip by 00z for the DC metro. Link to comment Share on other sites More sharing options...
BTRWx Posted January 17, 2013 Share Posted January 17, 2013 well... if we still follow the models any... 12z NAM finally tosses us in DC a bone... but is it too late? I see a tighter gradient again on the 12Z NAM, but I think the good stuff appears closer to the city during the bulk of the activity relative to recent runs. http://mag.ncep.noaa.gov/nam/12/nam_namer_015_precip_p12.gif Link to comment Share on other sites More sharing options...
WinterWxLuvr Posted January 17, 2013 Share Posted January 17, 2013 well... if we still follow the models any... 12z NAM finally tosses us in DC a bone... but is it too late? I hope y'all can pull it out, but it's probably just one more kick in the seeds. Link to comment Share on other sites More sharing options...
Yeoman Posted January 17, 2013 Share Posted January 17, 2013 Both the 12z NAM and 12z RAP shut off any precip by 00z for the DC metro. Being 45 degrees at 9am, at least anything that does fall should stick nicely Link to comment Share on other sites More sharing options...
WxMan1 Posted January 17, 2013 Share Posted January 17, 2013 Both the 12z NAM and 12z RAP shut off any precip by 00z for the DC metro. Yep, I see that. And that is too bad for us up here wanting snow. It's always "delicate" or precarious for us during events when the entire WAA side goes toward rain, and we're banking on a few or more hours of banded snows along/near the mid level deformation axis. Situations when the system has to generate it's own cold air, during the event, via column cooling, instead of having the antecedent cold air in place. Too many doubts with 1) how much moisture and 2) critical surface temps to feel comfy with getting anything over a dusting to an inch for most. Oh well.. Link to comment Share on other sites More sharing options...
ag3 Posted January 17, 2013 Share Posted January 17, 2013 NAM gives DC .31" of total precip. Similar to the new srefs. Here is a total precip map from the 9z srefs: Link to comment Share on other sites More sharing options...
ag3 Posted January 17, 2013 Share Posted January 17, 2013 12z NAM text output for DC. 1st bold is surface temp. 2nd is 850 temps and 3rd bold is previous 6 hours precip: THU 1P 17-JAN 5.2 -0.8 1020 73 87 0.07 564 547 THU 7P 17-JAN 2.0 -4.1 1021 90 76 0.21 558 542 FRI 1A 18-JAN 1.9 -5.1 1020 86 35 0.03 555 539 Link to comment Share on other sites More sharing options...
usedtobe Posted January 17, 2013 Share Posted January 17, 2013 NAM gives DC .31" of total precip. Similar to the new srefs. Here is a total precip map from the 9z srefs: Ask yourself how much of that is rain versus snow. The soundings suggest quite a bit of it and my 40 degree temp also argues that most will be wasted until dark. Link to comment Share on other sites More sharing options...
WxMan1 Posted January 17, 2013 Share Posted January 17, 2013 NAM gives DC .31" of total precip. Similar to the new srefs. Here is a total precip map from the 9z srefs: ...yes, but only .11" of which falls from 21-09Z. And if we're not sufficiently cold yet by 00Z, guess how much pcpn the new NAM has btwn 00-12Z? 0.00. Next system please... Link to comment Share on other sites More sharing options...
ag3 Posted January 17, 2013 Share Posted January 17, 2013 Ask yourself how much of that is rain versus snow. The soundings suggest quite a bit of it and my 40 degree temp also argues that most will be wasted until dark. Definitely. The 1st half is rain/slop. Skew-T soundings support snow for the last half of the storm. Will probably only stick to grassy areas (becasue of surface temps), but snow is snow. P.S. I dont live anywhere near this area. I'm just trying to help out since I see people are pretty down in this sub-forum. Link to comment Share on other sites More sharing options...
usedtobe Posted January 17, 2013 Share Posted January 17, 2013 ...yes, but only .11" of which falls from 21-09Z. And if we're not sufficiently cold yet by 00Z, guess how much pcpn the new NAM has btwn 00-12Z? 0.00. Next system please... The models trended a lot warmer over the past 24hrs and only some of that was due to the lighter precip most was due to the lack of cold air initially. Looks like yesterday's warmer GFS soundings were closer to being right than the NAMs. Link to comment Share on other sites More sharing options...
wasnow215 Posted January 17, 2013 Share Posted January 17, 2013 ...yes, but only .11" of which falls from 21-09Z. And if we're not sufficiently cold yet by 00Z, guess how much pcpn the new NAM has btwn 00-12Z? 0.00. Next system please... maybe for DC but for ezf and places like it...this system please. Link to comment Share on other sites More sharing options...
Deck Pic Posted January 17, 2013 Share Posted January 17, 2013 The models trended a lot warmer over the past 24hrs and only some of that was due to the lighter precip most was due to the lack of cold air initially. Looks like yesterday's warmer GFS soundings were closer to being right than the NAMs. shocker Link to comment Share on other sites More sharing options...
ag3 Posted January 17, 2013 Share Posted January 17, 2013 ...yes, but only .11" of which falls from 21-09Z. And if we're not sufficiently cold yet by 00Z, guess how much pcpn the new NAM has btwn 00-12Z? 0.00. Next system please... Yeah. Soundings are iffy, but there should at least be snow falling. Here is hour 9 off the 12z NAM: Link to comment Share on other sites More sharing options...
ag3 Posted January 17, 2013 Share Posted January 17, 2013 maybe for DC but for ezf and places like it...this system please. Yeah. EZF sounding at hour 9, is better then DCA. Mostly because of the heavier precip able to cool the last 100mb of the atmosphere: Link to comment Share on other sites More sharing options...
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