CoastalWx Posted March 10, 2013 Share Posted March 10, 2013 It's also a reason why frictional convergence aids in QPF bumps along the MA coast. Link to comment Share on other sites More sharing options...
Arnold214 Posted March 10, 2013 Share Posted March 10, 2013 Yeah if you have an environment that is already prone to DVM..then the flow off the hills is the nail on the coffin. I'm just totally shocked it stayed so persistent. Maybe you have, but I have never seen anything like that. Just incredible.I gotta imagine the bottleneck in the atmosphere may have helped in the persistence of this. Yeah I have never seen something like this so persistent unless it is purely terrain related. Northeast low level flow events generally don't do this down there. I'm pretty sure the cause (or most of the cause) was the persistent downglide but why that happened in the first place I have no idea. Link to comment Share on other sites More sharing options...
eekuasepinniW Posted March 10, 2013 Share Posted March 10, 2013 test. Link to comment Share on other sites More sharing options...
eekuasepinniW Posted March 10, 2013 Share Posted March 10, 2013 oh holy crap it worked. I copied over just the new file that I thought handled image processing rather than everything. why didn't I think of this 2 months ago. Link to comment Share on other sites More sharing options...
Arnold214 Posted March 10, 2013 Share Posted March 10, 2013 oh holy crap it worked. I copied over just the new file that I thought handled image processing rather than everything. why didn't I think of this 2 months ago. Ok. I'll try now. Link to comment Share on other sites More sharing options...
Damage In Tolland Posted March 10, 2013 Share Posted March 10, 2013 On that image Eek posted you can see how the echoes contined to blossom over the hills around here. They kept re generating in that same area and then that monster band came in from Windham County. And you can also see the down sloping in the valley to the west from Springfield down to HFD. Based on that you have to say the terrain helped us here in NE CT. That sinking motion out over RI had to come back up and it seems like the hills were able to make that happen Link to comment Share on other sites More sharing options...
ORH_wxman Posted March 10, 2013 Share Posted March 10, 2013 On that image Eek posted you can see how the echoes contined to blossom over the hills around here. They kept re generating in that same area and then that monster band came in from Windham County. And you can also see the down sloping in the valley to the west from Springfield down to HFD. Based on that you have to say the terrain helped us here in NE CT. That sinking motion out over RI had to come back up and it seems like the hills were able to make that happen The terrain was a pretty minor factor down there IMHO...it was some sort of mesoscale interaction probably with the two phasing upper air lows. Terrain is only a notable factor there if the BL wind is out of the south or southeast. If terrain has been a larger factor in that whole setup, we would have seen the echoes immediately regenerate in the RI hills...and we didn't see that happen. Link to comment Share on other sites More sharing options...
Damage In Tolland Posted March 10, 2013 Share Posted March 10, 2013 The terrain was a pretty minor factor down there IMHO...it was some sort of mesoscale interaction probably with the two phasing upper air lows. Terrain is only a notable factor there if the BL wind is out of the south or southeast. If terrain has been a larger factor in that whole setup, we would have seen the echoes immediately regenerate in the RI hills...and we didn't see that happen. But they were right to west of the up glide over SE Mass and I remember asking this before the storm but those are 300-500 feet lower than our hills and there wasn't enough lift there or enough time to get the precip going again. You had that reestablish that fetch over a longer period of time and distance and that meant it would look for the next highest spot once it had travelled enough distance. That's why the valley down sloped . It's very clear on that radar Link to comment Share on other sites More sharing options...
ORH_wxman Posted March 11, 2013 Share Posted March 11, 2013 But they were right to west of the up glide over SE Mass and I remember asking this before the storm but those are 300-500 feet lower than our hills and there wasn't enough lift there or enough time to get the precip going again. You had that reestablish that fetch over a longer period of time and distance and that meant it would look for the next highest spot once it had travelled enough distance. That's why the valley down sloped . It's very clear on that radar The area of enchancement in NE CT is likely related to the snow hole over RI...not upslope/downslope. You get upward motion in SE MA and then an area of enhancement downward motion over RI and then back upward again. Likely due to whatever mesoscale feature got stuck over RI from the phasing ULLs. The terrain argument makes no sense...again it would have immediately started regenerating over NW RI where the largest terrain difference over a short distance occurs on a large enough scale to matter. ITs very possible the valley to the west was downsloping...but the main effect we are talking about right now is the RI hole which had no terrain involvement. Link to comment Share on other sites More sharing options...
CoastalWx Posted March 11, 2013 Share Posted March 11, 2013 The terrain issue could have been an issue over se ct but I still can't grasp what in the sam hell Caused that persistent downglide over RI for 24 hrs. Link to comment Share on other sites More sharing options...
CoastalWx Posted March 11, 2013 Share Posted March 11, 2013 Mike thanks for images. Link to comment Share on other sites More sharing options...
Arnold214 Posted March 11, 2013 Share Posted March 11, 2013 The terrain issue could have been an issue over se ct but I still can't grasp what in the sam hell Caused that persistent downglide over RI for 24 hrs. Really don't know. My first guess would probably be something like deep layer mass piling on the mass coastline caused a standing-wave like pattern. But, I have no way to verify that or even if it is possible. In talking with walt this evening he seems to recall another storm in the mid or late 90s that produced similar results but couldn't remember exact dates. Link to comment Share on other sites More sharing options...
free_man Posted March 11, 2013 Share Posted March 11, 2013 The intense OEH bands over E MA would lead to a natural area of subsidence? "Between bands". Vaguely reminds me of '96. Big differences from south shore M over to RI. Different setup/orientation though. Do the Blue Hills chain have any subtle impact? Is there a slight downslope from Sharon/Foxboro to N RI hills, downward... depending on the sfc wind? Link to comment Share on other sites More sharing options...
CoastalWx Posted March 11, 2013 Share Posted March 11, 2013 We sometimes see a quick drop off in QPF over RI and ern CT with deep layer easterly flow like that, but that up-down-up pattern is something I can't recall. I thank my lucky stars I was not caught in that. Link to comment Share on other sites More sharing options...
CoastalWx Posted March 11, 2013 Share Posted March 11, 2013 The intense OEH bands over E MA would lead to a natural area of subsidence? "Between bands". Vaguely reminds me of '96. Big differences from south shore M over to RI. Different setup/orientation though. Do the Blue Hills chain have any subtle impact? Is there a slight downslope from Sharon/Foxboro to N RI hills, downward... depending on the sfc wind? I'm sure the hills from Brookline on se to the Blue Hils which stretch into Quincy have some effect in terms of upslope. They defitnely do not have much rise, but when you have 50-60 kts of inflow at 500-1000' and the lower levels are moist and unstable....those hills add in srfc convergence and the lift justs gives those bands added oomph. I don't they have that much effect in downsloping, but perhaps slightly if the atmospheric profile allows it....but I don't think it's much. Places like RI may have less moisture since much of it gets squeezed out to the northeast unless mesoscale processes like frontogenesis help out there. Link to comment Share on other sites More sharing options...
free_man Posted March 11, 2013 Share Posted March 11, 2013 I'm sure the hills from Brookline on se to the Blue Hils which stretch into Quincy have some effect in terms of upslope. They defitnely do not have much rise, but when you have 50-60 kts of inflow at 500-1000' and the lower levels are moist and unstable....those hills add in srfc convergence and the lift justs gives those bands added oomph. I don't they have that much effect in downsloping, but perhaps slightly if the atmospheric profile allows it....but I don't think it's much. Places like RI may have less moisture since much of it gets squeezed out to the northeast unless mesoscale processes like frontogenesis help out there. RI was jackpotting the lulls! That aspect interests me much more than the actual jackpots. A very primitive and amateur point I would make is that if MQE can get that little enhancement from time to time, then there must be some small price to pay downstream -especially with the remaining hills downstream like Moose Hill, and etc. They're all higher than anything in the eastern 2/3 or 3/4 of RI. And the majority of the precip from that OEH stuff is wrung out there. Not unlike, "for every high there must be a low". Link to comment Share on other sites More sharing options...
CT Rain Posted March 14, 2013 Share Posted March 14, 2013 Really don't know. My first guess would probably be something like deep layer mass piling on the mass coastline caused a standing-wave like pattern. But, I have no way to verify that or even if it is possible. In talking with walt this evening he seems to recall another storm in the mid or late 90s that produced similar results but couldn't remember exact dates. Just saw these images. Nice. The first thing I thought was the same thing.... some type of standing wave pattern from the strong convergence over E Mass. Link to comment Share on other sites More sharing options...
CoastalWx Posted March 14, 2013 Share Posted March 14, 2013 Just saw these images. Nice. The first thing I thought was the same thing.... some type of standing wave pattern from the strong convergence over E Mass. But that's the thing...I can't think of something lasting that long....just insane. Link to comment Share on other sites More sharing options...
Ginx snewx Posted March 14, 2013 Share Posted March 14, 2013 But that's the thing...I can't think of something lasting that long....just insane.What really intrigued me was as the axis pinwheeled and the flow veered in the final hours the drying continued. I can see how a consistent piling would be repeated over and over but when the geometry changed the effect did not. I knew that night once I figured out after the third time of hearing an approaching roar, subsequent radar blow up to my west and instant calm with a quick burst of snow that this was unlike any storm I had witnessed. It really was a memorable experience being right on the edge of a total whiff. Link to comment Share on other sites More sharing options...
CT Rain Posted March 14, 2013 Share Posted March 14, 2013 But that's the thing...I can't think of something lasting that long....just insane. Probably was since the flow and TROWAL setup was just so long lasting. It seemed like the neverending storm with only one mechanism of lift. It's not like we went through WCB and then flipped into some deformation on the back end. Link to comment Share on other sites More sharing options...
CT Rain Posted March 14, 2013 Share Posted March 14, 2013 What really intrigued me was as the axis pinwheeled and the flow veered in the final hours the drying continued. I can see how a consistent piling would be repeated over and over but when the geometry changed the effect did not. I knew that night once I figured out after the third time of hearing an approaching roar, subsequent radar blow up to my west and instant calm with a quick burst of snow that this was unlike any storm I had witnessed. It really was a memorable experience being right on the edge of a total whiff. Definition of NB. lol. What was so odd with this one was how localized some of the banding was. Glastonbury (same elevation as here in the valley) wound up with nearly 20" and we struggled to 7". It wasn't downsloping but it was likely a more modest example of what the had in RI... with some very shallow DVM. The radar would have looked a lot uglier had we been closer to any radar site. Link to comment Share on other sites More sharing options...
Baroclinic Zone Posted March 15, 2013 Share Posted March 15, 2013 May have been posted somewhere already but here is the NESIS Rating for the system. #36 on the list http://www.ncdc.noaa.gov/snow-and-ice/rsi/nesis Link to comment Share on other sites More sharing options...
joey2002 Posted March 16, 2013 Share Posted March 16, 2013 This NWS map wasn't final, but it showed just how sharply the snowfall totals went from 6" to 20"... Link to comment Share on other sites More sharing options...
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