Warwick WX Posted December 11, 2019 Share Posted December 11, 2019 Some mood snow still hanging on for dear life in Dedham, thought it would be over by now. Eyeballing the depth outside it appears in the 3" range. Link to comment Share on other sites More sharing options...
CoastalWx Posted December 11, 2019 Share Posted December 11, 2019 Kills me not to be home. Hopefully over 4 now. Link to comment Share on other sites More sharing options...
TauntonBlizzard2013 Posted December 11, 2019 Share Posted December 11, 2019 Let’s see if this last little pulse can push us to half a foot Link to comment Share on other sites More sharing options...
wxeyeNH Posted December 11, 2019 Share Posted December 11, 2019 Sharp back edge to the clouds. Beautiful day inbound down there. Come north young men to see bare ground! 1 2 3 1 Link to comment Share on other sites More sharing options...
40/70 Benchmark Posted December 11, 2019 Share Posted December 11, 2019 35 minutes ago, ORH_wxman said: You can see how good the snow growth was in that pic. This storm had high ratios. Esp elevated terrain where they didn't lose much qpf on the front end of the changeover. Dendritic growth was excellent and that variable was actually portrayed very consistently on model guidance. One lesson this event should probably drive home is when there is really good snow growth progged, don't get too bearish/pessimistic. Cross hair structure makes up for many different types of sins on an event. If the lift had been progged to be maxing out near that layer of dry air, then it would have been different. But in this case, it was above the dry air in a saturated snow growth zone. This is what I need to work on....my sounding interpretation. Killed me here...this is why this situation was an exception to the rule. I missed that. Link to comment Share on other sites More sharing options...
dendrite Posted December 11, 2019 Share Posted December 11, 2019 41 minutes ago, ORH_wxman said: You can see how good the snow growth was in that pic. This storm had high ratios. Esp elevated terrain where they didn't lose much qpf on the front end of the changeover. Dendritic growth was excellent and that variable was actually portrayed very consistently on model guidance. One lesson this event should probably drive home is when there is really good snow growth progged, don't get too bearish/pessimistic. Cross hair structure makes up for many different types of sins on an event. If the lift had been progged to be maxing out near that layer of dry air, then it would have been different. But in this case, it was above the dry air in a saturated snow growth zone. Yup...good midlevel fronto with big omega crosshaired in the DGZ. Idk why we trust the GFS with its low levels either. It was probably too gung-ho with the H8 dry advection. I think I mentioned yesterday how the mesos had been more moist in that layer. 2 Link to comment Share on other sites More sharing options...
40/70 Benchmark Posted December 11, 2019 Share Posted December 11, 2019 46 minutes ago, ORH_wxman said: You can see how good the snow growth was in that pic. This storm had high ratios. Esp elevated terrain where they didn't lose much qpf on the front end of the changeover. Dendritic growth was excellent and that variable was actually portrayed very consistently on model guidance. One lesson this event should probably drive home is when there is really good snow growth progged, don't get too bearish/pessimistic. Cross hair structure makes up for many different types of sins on an event. If the lift had been progged to be maxing out near that layer of dry air, then it would have been different. But in this case, it was above the dry air in a saturated snow growth zone. Would checking for frontogenesis in mid levels and seeing if it aligns with high RH allow for proper diagnosis? Link to comment Share on other sites More sharing options...
40/70 Benchmark Posted December 11, 2019 Share Posted December 11, 2019 41 minutes ago, Ginx snewx said: You started mentioning it yesterday and yes I do pay attention to your posts. Lol good job identifying that. Looks like it's over here. 4.3 final Your sounding skill paid off here. Good job. Link to comment Share on other sites More sharing options...
dendrite Posted December 11, 2019 Share Posted December 11, 2019 13 minutes ago, wxeyeNH said: Sharp back edge to the clouds. Beautiful day inbound down there. Come north young men to see bare ground! Tropical Northfield. 1 Link to comment Share on other sites More sharing options...
TauntonBlizzard2013 Posted December 11, 2019 Share Posted December 11, 2019 Dumping dendrites.... vis is low. About half a foot Link to comment Share on other sites More sharing options...
subdude Posted December 11, 2019 Share Posted December 11, 2019 nice numbers for everyone. pics in Northfield NH are Link to comment Share on other sites More sharing options...
weatherwiz Posted December 11, 2019 Share Posted December 11, 2019 6 minutes ago, dendrite said: Yup...good midlevel fronto with big omega crosshaired in the DGZ. Idk why we trust the GFS with its low levels either. It was probably too gung-ho with the H8 dry advection. I think I mentioned yesterday how the mesos had been more moist in that layer. Let's say that the dry air did get in here...would you think this plays out differently? When you look at the observed soundings from last night just behind the front...that dry air was legit...something prevented the dry air from really creeping in...maybe evap cooling, CAA, and rapid upward motion offset this drying? Link to comment Share on other sites More sharing options...
Briz600 Posted December 11, 2019 Share Posted December 11, 2019 Little over 4 here which is what I expected. Link to comment Share on other sites More sharing options...
dendrite Posted December 11, 2019 Share Posted December 11, 2019 8 minutes ago, 40/70 Benchmark said: Would checking for frontogenesis in mid levels and seeing if it aligns with high RH allow for proper diagnosis? 00z 3km NAM from last night...cross sections through that banding. You can see the omega bullseye "crosshaired" through that max DGZ of -12C to -18C. That's pretty damn high up at 500mb, but if you look at the lower image the RH was high enough for deposition with respect to ice. Also, it was just moist enough in the low levels to prevent virga. This suggests a pretty sharp cutoff though with the sinking air just west of the banding and lower RH. 1 Link to comment Share on other sites More sharing options...
OSUmetstud Posted December 11, 2019 Share Posted December 11, 2019 2 minutes ago, weatherwiz said: Let's say that the dry air did get in here...would you think this plays out differently? When you look at the observed soundings from last night just behind the front...that dry air was legit...something prevented the dry air from really creeping in...maybe evap cooling, CAA, and rapid upward motion offset this drying? Because it SNE and you guys are on like a 15 to 20 year heater? Link to comment Share on other sites More sharing options...
40/70 Benchmark Posted December 11, 2019 Share Posted December 11, 2019 2 minutes ago, weatherwiz said: Let's say that the dry air did get in here...would you think this plays out differently? When you look at the observed soundings from last night just behind the front...that dry air was legit...something prevented the dry air from really creeping in...maybe evap cooling, CAA, and rapid upward motion offset this drying? I looked out and saw the snowgrowth last night, and knew that I had made a bad call...slow progression of RAD confirmed. Link to comment Share on other sites More sharing options...
40/70 Benchmark Posted December 11, 2019 Share Posted December 11, 2019 2 minutes ago, dendrite said: 00z 3km NAM from last night...cross sections through that banding. You can see the omega bullseye "crosshaired" through that max DGZ of -12C to -18C. That's pretty damn high up at 500mb, but if you look at the lower image the RH was high enough for deposition with respect to ice. Also, it was just moist enough in the low levels to prevent virga. This suggests a pretty sharp cutoff though with the sinking air just west of the banding and lower RH. Can you diagnose that via charts? Link to comment Share on other sites More sharing options...
dendrite Posted December 11, 2019 Share Posted December 11, 2019 2 minutes ago, weatherwiz said: Let's say that the dry air did get in here...would you think this plays out differently? When you look at the observed soundings from last night just behind the front...that dry air was legit...something prevented the dry air from really creeping in...maybe evap cooling, CAA, and rapid upward motion offset this drying? I think the GFS was just overzealous with the dry air. The precip was heavy enough too to keep any slightly drying layer saturated with sublimational wetbulbing. That 3km NAM I just posted was a lot more moist at H8 over C CT than the GFS was. Link to comment Share on other sites More sharing options...
DavisStraight Posted December 11, 2019 Share Posted December 11, 2019 1 hour ago, Ginx snewx said: Here's their pic. Rutland is 1200' el, they always do well. Link to comment Share on other sites More sharing options...
weatherwiz Posted December 11, 2019 Share Posted December 11, 2019 1 minute ago, OSUmetstud said: Because it SNE and you guys are on like a 15 to 20 year heater? Not sure I understand Just now, 40/70 Benchmark said: I looked out and saw the snowgrowth last night, and knew that I had made a bad call...slow progression of RAD confirmed. I guess that's what my mistake was...there is no question snowgrowth was going to be great...even looking at bufkit soundings all week...there was great omega into the DGZ with sufficient RH...but for some reason I thought the dry air/subsidence in the llvls would win out. At the end of the day I just don't think the dry air worked in like what was modeled...if it did maybe it would have been different. But OTOH great omega into the DGZ doesn't only help support great snowgrowth...it also promotes high precip rates. Link to comment Share on other sites More sharing options...
40/70 Benchmark Posted December 11, 2019 Share Posted December 11, 2019 Yea, 3-6" was good south of here, but I, think up here 2-4 or 1-3 was more appropriate. Link to comment Share on other sites More sharing options...
weatherwiz Posted December 11, 2019 Share Posted December 11, 2019 1 minute ago, dendrite said: I think the GFS was just overzealous with the dry air. The precip was heavy enough too to keep any slightly drying layer saturated with sublimational wetbulbing. That 3km NAM I just posted was a lot more moist at H8 over C CT than the GFS was. Makes a great deal of sense...certainly going to make mental note of this for the future. I also need to do more with cross-sectional analysis...a more dedicated analysis of cross-sections could have yielded a different thought/interpretation process from me. Link to comment Share on other sites More sharing options...
40/70 Benchmark Posted December 11, 2019 Share Posted December 11, 2019 Just now, weatherwiz said: Not sure I understand I guess that's what my mistake was...there is no question snowgrowth was going to be great...even looking at bufkit soundings all week...there was great omega into the DGZ with sufficient RH...but for some reason I thought the dry air/subsidence in the llvls would win out. At the end of the day I just don't think the dry air worked in like what was modeled...if it did maybe it would have been different. But OTOH great omega into the DGZ doesn't only help support great snowgrowth...it also promotes high precip rates. I need to incorporate soundings more....I get away with it in big dogs, but there smaller marginal events can burn me. Link to comment Share on other sites More sharing options...
dendrite Posted December 11, 2019 Share Posted December 11, 2019 2 minutes ago, 40/70 Benchmark said: Can you diagnose that via charts? I'm not sure what you're asking. Diagnose what specifically? Link to comment Share on other sites More sharing options...
40/70 Benchmark Posted December 11, 2019 Share Posted December 11, 2019 2 minutes ago, dendrite said: I think the GFS was just overzealous with the dry air. The precip was heavy enough too to keep any slightly drying layer saturated with sublimational wetbulbing. That 3km NAM I just posted was a lot more moist at H8 over C CT than the GFS was. Even the EURO snow map from 12z yesterday was like 1-2"... Link to comment Share on other sites More sharing options...
weatherwiz Posted December 11, 2019 Share Posted December 11, 2019 Just now, 40/70 Benchmark said: I need to incorporate soundings more....I get away with it in big dogs, but there smaller marginal events can burn me. It can be tough to incorporate soundings...moreso b/c its more work then just analyzing charts...clicking and generating soundings...ughhh. Soundings are a tremendous value though as we get inside 24...even 36 hours. Sometimes what I'll do is pick some "key locations"...so like pick a western location, northern, southern, and eastern...and just see how the structure of the atmosphere compares across these point locations Link to comment Share on other sites More sharing options...
40/70 Benchmark Posted December 11, 2019 Share Posted December 11, 2019 Just now, dendrite said: I'm not sure what you're asking. Diagnose what specifically? OMEGA and RH level and alignment...what exactly ials OMEGA, lift/deformation? This is where the lack of met degree shows... Link to comment Share on other sites More sharing options...
dendrite Posted December 11, 2019 Share Posted December 11, 2019 Just now, 40/70 Benchmark said: Even the EURO snow map from 12z yesterday was like 1-2"... Yeah but that was 10:1 right? Maybe QPF overperformed a bit, but the banding looked pretty good so that's not too surprising. I didn't see coco obs, but I assume some of the bigger totals were pushing 15-20:1? Link to comment Share on other sites More sharing options...
weatherwiz Posted December 11, 2019 Share Posted December 11, 2019 I'll chime in as well. Do you have bufkit, Ray? If not coolwx.com has great tools to see what you could with bufkit. coolwx.com > Hourly forecast models > then you can choose plot, station, and model on the left hand side. Here is the 0z 3K NAM for BDL: 1. the -12C to -18C range is illustrated...this is where snow growth is most optimized 2. I highlighted by the purple box where the negative values of omega area (negative values of omega indicate rising motion). Notice how you have very negative values of omega right inside the snowgrowth zone...this is referred to as a "cross hair signature". When this occurs and you have sufficient ice and RH in this layer (what's great about bufkit is you can overly RH with this...I'll post an example) you're not only going to maximize snow growth...but you're going to get very intense precip rates 3. I circled area of dry air in the low-levels around 6z or so...that was my flag for all this Now let's look at the RH profile. The time of snow was prior to 12z...well the heaviest anyways. Notice something...very moist...the dry air in the lower levels doesn't take over until around 12z...AFTER the precip has fallen. My mistake here was harping that drier air would be in place earlier...but between 0z-12z...you have a very deep moist profile here (noted by the high RH values through the troposphere 1 1 Link to comment Share on other sites More sharing options...
SouthCoastMA Posted December 11, 2019 Share Posted December 11, 2019 Heavy snow. Measuring in a bit Link to comment Share on other sites More sharing options...
Recommended Posts
Create an account or sign in to comment
You need to be a member in order to leave a comment
Create an account
Sign up for a new account in our community. It's easy!
Register a new accountSign in
Already have an account? Sign in here.
Sign In Now