baroclinic_instability Posted January 30, 2011 Share Posted January 30, 2011 On this note, something else I posted elsewhere about SLR: + Positives Very deep dendritic growth zone/ice crystal formation zone, in some cases approaching 400mb, especially early Wednesday near the peak. Very cold profiles (850s around -10 to -15C) Deep/strong and persistent omega field intersected with DGZ High wind shear aloft in deep DGZ will cause enhanced dendritic/ice crystal shattering, which will actually help seed snow production in the lower cold layers (seeder-feeder type process). - Negatives High winds and wind shear will shatter dendrites as they hit the ground, tempering the ratio somewhat. Compaction from large amounts of snow Still thinking an average of 16-17:1 after this all shakes out. I do think we could get past 20:1 in the early morning hours of Wednesday as the DGZ approaches 400mb and the peak of the storm arrives. I always like your posts on ice crystal microphysics and snow ratios. Me thinks you did some research sometime in your career? Link to comment Share on other sites More sharing options...
Hoosier Posted January 30, 2011 Author Share Posted January 30, 2011 Just woke up to see two facebook posts from TV mets in Indy (different station) One is talking about the stormtrack, and how the Indy area is looking at our biggest ice event since 04.... The other says the low has shifted W enough that the main threat of damaging contions goes from Laf to Fort Wayne. Talk about a confusing message! Sent from my Droid using Tapatalk This is an awfully tough call. Right now the best icing potential looks to be just south of LAF/FWA, but the risk of it shifting slightly and catching some areas off guard is very real. Link to comment Share on other sites More sharing options...
Thundersnow12 Posted January 30, 2011 Share Posted January 30, 2011 We will likely see a 70% of 12" on those maps as we get closer. Link to comment Share on other sites More sharing options...
snowstormcanuck Posted January 30, 2011 Share Posted January 30, 2011 18z GFS looks the same at 48hr Looks a little slower at 54. Link to comment Share on other sites More sharing options...
csnavywx Posted January 30, 2011 Share Posted January 30, 2011 The negatives actually make the public impacts of this storm worse! The blowing, drifting and white out conditions are going to make travel, snow removal, etc. impossible. Haha, that's very true. Link to comment Share on other sites More sharing options...
cyclone77 Posted January 30, 2011 Share Posted January 30, 2011 15z SREF 12hr snowfall mean Link to comment Share on other sites More sharing options...
B-Rent Posted January 30, 2011 Share Posted January 30, 2011 This is an awfully tough call. Right now the best icing potential looks to be just south of LAF/FWA, but the risk of it shifting slightly and catching some areas off guard is very real.<br /> I don't know how much Indy media you watch, but if this busts in the metro, there's going to be a lot of confidence lost. They sounded the bread and milk alarm already, can't take that back. Sent from my Droid using Tapatalk Link to comment Share on other sites More sharing options...
baroclinic_instability Posted January 30, 2011 Share Posted January 30, 2011 GFS did shift W in the overall trough and height field config--so some credence can be given to that solution. NAM is too far W with the overall trough though. Link to comment Share on other sites More sharing options...
Thundersnow12 Posted January 30, 2011 Share Posted January 30, 2011 The sfc low is a hair west of the 12z run, sitting in extreme northeast AR on this run. Link to comment Share on other sites More sharing options...
csnavywx Posted January 30, 2011 Share Posted January 30, 2011 I always like your posts on ice crystal microphysics and snow ratios. Me thinks you did some research sometime in your career? Just lots of study on this subject. After running into some problems forecasting snow ratios one time, I decided to sit down and solve the problem by reading all I could about it. Fascinating stuff, really. There were a few cases (similar to this one) where the snow totals and rates were higher than expected due to that dual DGZ structure in the profile and high wind shear. It resulted in the upper DGZ furiously seeding the lower one with ice crystals and resulted in very efficient snow production. Link to comment Share on other sites More sharing options...
snowstormcanuck Posted January 30, 2011 Share Posted January 30, 2011 Echoing what OL said earlier, I'm leaning away from this being a historically significant snowstorm the further east you go. Should still easily be the biggest storm of the year though. Link to comment Share on other sites More sharing options...
npcougar Posted January 30, 2011 Share Posted January 30, 2011 That run looked pretty icy for central indiana. Link to comment Share on other sites More sharing options...
Thundersnow12 Posted January 30, 2011 Share Posted January 30, 2011 sfc low track is hair west of the 12z but barely. Link to comment Share on other sites More sharing options...
hawkeye_wx Posted January 30, 2011 Share Posted January 30, 2011 With the slower movement on the 18z NAM and GFS runs, they both also have a bit more push from the north over the upper midwest/great lakes. Each model has shifted a bit south with the qpf up here. Link to comment Share on other sites More sharing options...
baroclinic_instability Posted January 30, 2011 Share Posted January 30, 2011 Just lots of study on this subject. After running into some problems forecasting snow ratios one time, I decided to sit down and solve the problem by reading all I could about it. Fascinating stuff, really. There were a few cases (similar to this one) where the snow totals and rates were higher than expected due to that dual DGZ structure in the profile and high wind shear. It resulted in the upper DGZ furiously seeding the lower one with ice crystals and resulted in very efficient snow production. Snow ratios is definitely one of the hardest things to forecast. I definitely need to do more research into cloud microphysics. At UND we didn't do much as undergrads with cloud physics/microphysics. If you have any good links or information/papers send them this way--I would definitely be interested in giving it a read. Forecasting wise--snow ratios are affected by so many variables it is simply frustrating to say the least. The seeding scenario with dual DGZ's sounds really interesting. Link to comment Share on other sites More sharing options...
toronto blizzard Posted January 30, 2011 Share Posted January 30, 2011 Echoing what OL said earlier, I'm leaning away from this being a historically significant snowstorm the further east you go. Should still easily be the biggest storm of the year though. You still think 10-15"? Link to comment Share on other sites More sharing options...
TheWeatherPimp Posted January 30, 2011 Share Posted January 30, 2011 Both 18z NAM and 18z GFS colder across Central Indiana and Western Ohio FWIW Link to comment Share on other sites More sharing options...
wisconsinwx Posted January 30, 2011 Share Posted January 30, 2011 With the slower movement on the 18z NAM and GFS runs, they both also have a bit more push from the north over the upper midwest/great lakes. Each model has shifted a bit south with the qpf up here. Not good. Do you think that is a blip or a trend? Link to comment Share on other sites More sharing options...
Thundersnow12 Posted January 30, 2011 Share Posted January 30, 2011 > 1"/hr rates >100mb deep DGZ, seems a bit underdone given soundings are showing it being near 400mb deep for awhile. thats why we look at soundings and not just this lol Link to comment Share on other sites More sharing options...
Hoosier Posted January 30, 2011 Author Share Posted January 30, 2011 Both 18z NAM and 18z GFS colder across Central Indiana and Western Ohio FWIW It's close but LAF would be almost all snow especially on the GFS. My heart says yes but my brain says the warm air advection will be stronger. One of the most challenging setups I've seen around here...would be much easier being planted right in the middle of the heavy snow band. Link to comment Share on other sites More sharing options...
npcougar Posted January 30, 2011 Share Posted January 30, 2011 It's close but LAF would be almost all snow especially on the GFS. My heart says yes but my brain says the warm air advection will be stronger. One of the most challenging setups I've seen around here...would be much easier being planted right in the middle of the heavy snow band. Indy still looks at risk of a bad ice-storm. Link to comment Share on other sites More sharing options...
snowstormcanuck Posted January 30, 2011 Share Posted January 30, 2011 You still think 10-15"? lol, by our standards 15" would be historic. I said 8-14" earlier, and I'm starting to think the high end of that may be a stretch. There at least signs that the storm is going to max out to our west. Link to comment Share on other sites More sharing options...
hawkeye_wx Posted January 30, 2011 Share Posted January 30, 2011 SURFACE LOW FROM ROCKIES WILL PUSH EASTWARD...TO CENTRAL ARKANSAS...BEFORE LIFTING AND PIVOTING NORTHEAST LATE TUESDAY. UPPER LEVEL LOW WILL BE CENTERED OVER NORTHERN MISSOURI. THIS SOLUTION IS FURTHER EAST THAN PREVIOUS MODEL RUNS...BUT STILL HAS A LARGE IMPACT ON IOWA...WITH GREATEST IMPACT...FROM DEF ZONE PRECIP...ACROSS SE IOWA. LARGEST IMPACTS WILL BE TUESDAY...AS MOISTURE INCREASES ACROSS IOWA. EXTREMELY COLD TEMPERATURES MEAN THE DENDRITIC ZONE IS NEARLY COMPLETELY SATURATED...WITH GOOD SNOW PRODUCTION. SNOW RATIOS PUSH 20:1 ACROSS THE ENTIRE AREA TOWARDS END OF DAY TUESDAY. ATTM...TOTALLY SNOWFALL AMOUNTS SHOULD BE NEAR 10 INCHES IN THE NORTHWEST...COULD SEE NEAR A FOOT OF SNOW IN CENTRAL IOWA...WITH HIGHER AMOUNTS TO THE SOUTHEAST. 2 FEET IS NOT OUT OF THE QUESTION SE. HOWEVER...A BIG HOWEVER...EVEN THOUGH THE MODELS ARE IN GOOD AGREEMENT...STILL AM NOT SOLD ON PLACEMENT OF SYSTEM ON DAY 3. WOULD NOT BE SURPRISED TO SEE TRACK OF LOW CHANGE...ESPECIALLY PULLING FURTHER SOUTH OR BACK WESTWARD. THISWOULD HAVE A DRASTIC IMPACT ON PLACEMENT OF SNOWFALL TOTALS. Link to comment Share on other sites More sharing options...
baroclinic_instability Posted January 30, 2011 Share Posted January 30, 2011 Simply incredible. GFS sounding over N IL has 55+ kts easily to mix down within the dry adiabatic layer--that is potential for 60+ mph wind gusts and extremely fluffy snow. The blowing/drifting potential is simply hard to imagine. Link to comment Share on other sites More sharing options...
Thundersnow12 Posted January 30, 2011 Share Posted January 30, 2011 18z GFS trended down a bit here with 1.24" liquid. The NAM and Euro have been consistently higher. Link to comment Share on other sites More sharing options...
Harry Posted January 30, 2011 Share Posted January 30, 2011 It's close but LAF would be almost all snow especially on the GFS. My heart says yes but my brain says the warm air advection will be stronger. One of the most challenging setups I've seen around here...would be much easier being planted right in the middle of the heavy snow band. Amazing what a small nudge south will do huh? I mean how far is it from Cincy to Dayton? mention those because 12z had the surface low almost over Dayton at 72hrs while the 18z has it almost over Cincy at 66hrs. Link to comment Share on other sites More sharing options...
OceanStWx Posted January 30, 2011 Share Posted January 30, 2011 Snow ratios is definitely one of the hardest things to forecast. I definitely need to do more research into cloud microphysics. At UND we didn't do much as undergrads with cloud physics/microphysics. If you have any good links or information/papers send them this way--I would definitely be interested in giving it a read. Forecasting wise--snow ratios are affected by so many variables it is simply frustrating to say the least. The seeding scenario with dual DGZ's sounds really interesting. I believe it was ARX (Dan Baumgardt) that has done research on the extreme snow ratio events. I would check the "Items of Interest" part of their homepage to see if they have the study posted. Link to comment Share on other sites More sharing options...
patrick7032 Posted January 30, 2011 Share Posted January 30, 2011 Bufkit "BEST GUESSES" for the area for this storm. These are just straight 10:1 averages even though these areas should be in the 14:1 to 20:1 range based on what I am seeing....but for argumentative sake going straight 10:1 would yield in a 24 hr period based on the 12Z NAM: LOCATION: 10:1 15:1 ICE ACCUM DTX: 14.2 21.3 DTW 12.0 18.0 0.1 GRR 13.1 19.6 AZO 13.6 20.4 SBN 16.1 24.2 ORD 23.0 34.5 MKE 11.6 17.1 MKX 8.6 12.9 RFD 12.7 19.1 DVN 14.1 21.2 STL 2.4 3.6 1.45 Ice Pellets PIA 18.7 28.1 LAF 1.2 2.3 1.36 Ice Pellets DAY 0.2 0.3 0.32 Freezing Rain (lower totals due to dry slot and RA) Link to comment Share on other sites More sharing options...
Macintosh Posted January 30, 2011 Share Posted January 30, 2011 Wow a keeper Argh!!! Perry County, Missouri...RIGHT ON THE EDGE. Link to comment Share on other sites More sharing options...
cyclone77 Posted January 30, 2011 Share Posted January 30, 2011 With the slower movement on the 18z NAM and GFS runs, they both also have a bit more push from the north over the upper midwest/great lakes. Each model has shifted a bit south with the qpf up here. I think you're still in pretty good shape. The Euro has been amazingly consistent with the low track for the last 3-4 days. Everything has trended towards the Euro, starting with the NAM, and then the GFS/GEM. The SREF looks really nice as well. Ratios out your way will be even higher too. Link to comment Share on other sites More sharing options...
Recommended Posts
Archived
This topic is now archived and is closed to further replies.