Chinook Posted November 23, 2019 Author Share Posted November 23, 2019 Thanksgiving Week = traffic snarled with heavy snow across the country Link to comment Share on other sites More sharing options...
smokeybandit Posted November 24, 2019 Share Posted November 24, 2019 First time in my adult life I'm not traveling anywhere for Thanksgiving, so let it snow! Link to comment Share on other sites More sharing options...
Chinook Posted November 24, 2019 Author Share Posted November 24, 2019 NWS digital forecasts are now at 9.1" for Fort Collins-Loveland and also the same for Denver (Stapleton) up to Tuesday, 5:00PM. Link to comment Share on other sites More sharing options...
Chinook Posted November 24, 2019 Author Share Posted November 24, 2019 NWS digital forecast as of this morning Link to comment Share on other sites More sharing options...
MidlothianWX Posted November 25, 2019 Share Posted November 25, 2019 This looks like a BIG one for the northern Front Range folks. Couldn't ask for a better setup with the 700mb low track. Cold temps should make for some great ratios. My current record single-storm total out here is 13.5" so let's see if we can push past that Link to comment Share on other sites More sharing options...
Chinook Posted November 25, 2019 Author Share Posted November 25, 2019 Just for fun, I checked the SREF plumes for Fort Collins-Loveland, which have QPF values of 0.44" to 1.90", which could be 4.4" to 19.0" at 10:1 ratio. The GEFS plumes for GXY (Greeley) have 0.44" to 1.13" which could be 4.4" to 11.3". Also, just for fun, if you check the SPC web page, the HREF (high-resolution models ensemble) is within range to give a max snowfall amount. The regular NAM has 0.8" of QPF (Denver) up to 1.6" of QPF (Fort Collins-Loveland). Let's just say, in my entire time in Fort Collins/Loveland, the best November snowstorms were 7.4" in 2006, and 9.0" in 2011. When I lived in the Midwest, November did not produce this type of snow. Link to comment Share on other sites More sharing options...
raindancewx Posted November 25, 2019 Share Posted November 25, 2019 This is one of the widest spreads I've ever seen for Albuquerque within 84 hours - literally near 0 rain to near 10 inches of snow. I've been leaning toward a coating to three with some rain, but I'd like to see the European win. Link to comment Share on other sites More sharing options...
mayjawintastawm Posted November 25, 2019 Share Posted November 25, 2019 OK, just as things were getting consistent with around a foot of snow for Denver metro, some models are pulling the plug less than 12 hours before things start, especially in my neck of the woods. WTF?? I can look at GFS, NAM and HRRR. GFS is backing off some (6-9 inches); NAM backing off a bit more (like 5-7), and HRRR keeps the Metro area completely dry through midnight while whacking Fort Collins with over an inch of precip. Jeesh. Link to comment Share on other sites More sharing options...
MidlothianWX Posted November 25, 2019 Share Posted November 25, 2019 Here is QPF from the 18z NAM for the Front Range: I know it's the NAM but it's fun to look at. If you are in Longmont/Berthoud right now, watch out. Boulder looks to be just shy of 2" on that. I'm getting really pumped about this one - I haven't seen over 16" IMBY since PDII in 2003. Link to comment Share on other sites More sharing options...
ValpoVike Posted November 25, 2019 Share Posted November 25, 2019 Snow ratios are going to be important tonight. What is the current thinking on that? I saw NWS discussion of 15:1 +, but that was a day or so ago... Link to comment Share on other sites More sharing options...
MidlothianWX Posted November 25, 2019 Share Posted November 25, 2019 16 minutes ago, ValpoVike said: Snow ratios are going to be important tonight. What is the current thinking on that? I saw NWS discussion of 15:1 +, but that was a day or so ago... BoulderCAST was saying 15:1 for the most part with periods of up to 18:1. I haven't taken time to look at the soundings though. I'd tend to think you'll get in on some of the upslope action where you are. Link to comment Share on other sites More sharing options...
snowfan789 Posted November 25, 2019 Share Posted November 25, 2019 40 minutes ago, MidlothianWX said: Here is QPF from the 18z NAM for the Front Range: I know it's the NAM but it's fun to look at. If you are in Longmont/Berthoud right now, watch out. Boulder looks to be just shy of 2" on that. I'm getting really pumped about this one - I haven't seen over 16" IMBY since PDII in 2003. That’s a huge increase from the last run. Not sure if that’s indicative of a legitimately higher impact than anticipated but it’s sure fun to look at, and last-minute trends can be meaningful. I imagine that’d be a top-five storm for at least Boulder and Fort Collins if it verified. Link to comment Share on other sites More sharing options...
MidlothianWX Posted November 25, 2019 Share Posted November 25, 2019 19 minutes ago, snowfan789 said: That’s a huge increase from the last run. Not sure if that’s indicative of a legitimately higher impact than anticipated but it’s sure fun to look at, and last-minute trends can be meaningful. I imagine that’d be a top-five storm for at least Boulder and Fort Collins if it verified. Yeah, someone is going to get pounded with 2-3" /hr rates and I think the models are just honing in on where the upsloping/convergence takes place. Seems like NE Boulder and SE Larimer are the place to be right now for the qpf max but other factors could cause areas just west to win out. I lived in the Mid-Atlantic long enough to be NAM'd several times. Will be interesting to see what the 18z runs of the globals do. For Boulder proper, 23" would be top 10 all time and 26" would be top 5. Link to comment Share on other sites More sharing options...
MidlothianWX Posted November 25, 2019 Share Posted November 25, 2019 18z High Res GFS: Models seem to like Erie-Longmont-Berthoud for the QPF max. Link to comment Share on other sites More sharing options...
snowfan789 Posted November 25, 2019 Share Posted November 25, 2019 8 minutes ago, MidlothianWX said: 18z High Res GFS: Models seem to like Erie-Longmont-Berthoud for the QPF max. That’s also a little better than the last run for Denver, but not as dramatically so as the NAM. Still, latest trends = encouraging. Things could still change in the other direction but I think it’s reasonable to be cautiously optimistic at this point. Link to comment Share on other sites More sharing options...
snowfan789 Posted November 25, 2019 Share Posted November 25, 2019 46 minutes ago, MidlothianWX said: Yeah, someone is going to get pounded with 2-3" /hr rates and I think the models are just honing in on where the upsloping/convergence takes place. Seems like NE Boulder and SE Larimer are the place to be right now for the qpf max but other factors could cause areas just west to win out. I lived in the Mid-Atlantic long enough to be NAM'd several times. Will be interesting to see what the 18z runs of the globals do. For Boulder proper, 23" would be top 10 all time and 26" would be top 5. In my anecdotal experience, the NAM tends not to significantly over predict in Colorado. That is in contrast to the Nor’easters I used to experience when living in New England. Link to comment Share on other sites More sharing options...
smokeybandit Posted November 25, 2019 Share Posted November 25, 2019 NWS upped the floor amounts for most of the area. Link to comment Share on other sites More sharing options...
MidlothianWX Posted November 25, 2019 Share Posted November 25, 2019 7 minutes ago, snowfan789 said: In my anecdotal experience, the NAM tends not to significantly over predict in Colorado. That is in contrast to the Nor’easters I used to experience when living in New England. That's good to hear. I've been let down by way too many NAM fantasy maps in the DC/RIC area. Hoping Denver gets solid totals out of this one too. I wish I knew more about local snow climo, just haven't lived here long enough. From looking at historic "big ones", it appears that the bullseye outside of the upsloping spots is usually somewhere along I-25. Link to comment Share on other sites More sharing options...
MidlothianWX Posted November 25, 2019 Share Posted November 25, 2019 3 minutes ago, smokeybandit said: NWS upped the floor amounts for most of the area. I appreciate you moving out here man. Brought that solid MA HECS energy with you. Knowing how things go, it could be a while before another like this comes our way so let's enjoy it. Link to comment Share on other sites More sharing options...
smokeybandit Posted November 25, 2019 Share Posted November 25, 2019 Just now, MidlothianWX said: I appreciate you moving out here man. Brought that solid MA HECS energy with you. Knowing how things go, it could be a while before another like this comes our way so let's enjoy it. I do what I can. Link to comment Share on other sites More sharing options...
ValpoVike Posted November 25, 2019 Share Posted November 25, 2019 NWS has a narrow stripe of 33" (high end amounts) just into the foothills of Larimer basically on a Drake to Mishawaka line. Link to comment Share on other sites More sharing options...
mayjawintastawm Posted November 25, 2019 Share Posted November 25, 2019 36 minutes ago, snowfan789 said: In my anecdotal experience, the NAM tends not to significantly over predict in Colorado. That is in contrast to the Nor’easters I used to experience when living in New England. I know, right?! When I was in SNE it would have stupid high amounts, and here in CO it lives up to its name: the No Accumulation Model. Link to comment Share on other sites More sharing options...
Chinook Posted November 25, 2019 Author Share Posted November 25, 2019 Sometimes I'm not sure how the NAM deals with upslope flow when things are less obvious with upslope flow direction and speed. The GFS is more consistent at predicting snowfall amounts near my place. Anyway, the snow has started here at about 2:00 or slightly earlier. We already have 1" of snow in less than 2 hours. Greeley is above freezing with rain, currently. That will change quickly. At the end of the storm, I will make a loop of 850mb temps, 500mb vorticity, composite radar, and GFS-6hr precip/SLP. note: 18z models still have 10-12" at locations of 5-10 mi southeast of Denver, with ECMWF still at 10" (8" on map, but ratios will be higher than 10:1) Link to comment Share on other sites More sharing options...
ValpoVike Posted November 25, 2019 Share Posted November 25, 2019 Coming down pretty good up here northeast of EP. Nearly 3" so far over about 2.5 hours. So far so good on ratios as the flake size is good. Link to comment Share on other sites More sharing options...
smokeybandit Posted November 25, 2019 Share Posted November 25, 2019 Bonus snow squall here on the Palmer Divide to get the temps below freezing Link to comment Share on other sites More sharing options...
Chinook Posted November 26, 2019 Author Share Posted November 26, 2019 1 hour ago, ValpoVike said: Coming down pretty good up here northeast of EP. Nearly 3" so far over about 2.5 hours. So far so good on ratios as the flake size is good. It's nearly the same here, the radar shows a max of precipitation here at Loveland, Lyons, and Estes Park. Link to comment Share on other sites More sharing options...
MidlothianWX Posted November 26, 2019 Share Posted November 26, 2019 Just about 2" on the ground here with a temp of 29.5. Link to comment Share on other sites More sharing options...
MidlothianWX Posted November 26, 2019 Share Posted November 26, 2019 Looks like the Longmont-Loveland-Lyons triangle is getting smoked right now per radar. Link to comment Share on other sites More sharing options...
mayjawintastawm Posted November 26, 2019 Share Posted November 26, 2019 Greetings from the dry slot. Congrats to those in Longmont/Broomfield and points north! Loveland and FoCo were shafted so many times the past year... now it's your turn. We'll get into it, eventually, I hope. Link to comment Share on other sites More sharing options...
MidlothianWX Posted November 26, 2019 Share Posted November 26, 2019 0z NAM comes back down to earth just a bit with a qpf total of 1.55" for Boulder, which means all globals show between 1.5-1.6". HRRR seems to place the highest totals on a line from Lyons to Fort Collins. Death band is looking pretty sick right now. Currently 28 with heavy snow here. Link to comment Share on other sites More sharing options...
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