Ralph Wiggum Posted December 13, 2020 Share Posted December 13, 2020 Put all discussion here for the upcoming December 16-17 winter storm. Let's keep it on point and clean. 1 Link to comment Share on other sites More sharing options...
Ralph Wiggum Posted December 13, 2020 Author Share Posted December 13, 2020 GEFS are moist. 1 Link to comment Share on other sites More sharing options...
Newman Posted December 13, 2020 Share Posted December 13, 2020 The top CIPS analogs for this storm. I always find these interesting to look at regardless if they actually have any real value or not lol. 1 1 Link to comment Share on other sites More sharing options...
Rtd208 Posted December 14, 2020 Share Posted December 14, 2020 Winter Storm Watch just issued here. Wow early. 1 1 Link to comment Share on other sites More sharing options...
Moderately Unstable Posted December 14, 2020 Share Posted December 14, 2020 18z euro agrees with the gfs, high qpf, cold. Yay! Re WSA: quite true, but they seem on point. 5"+. 5 is the abs worst case I wrote down earlier. The fact is, no model, no ensemble member, says Philly et al gets advisory snow. May as well give folks more notice so they can get salt or what have you early, instead of all crowding in a store the day before the event..mid-covid surge. We know it will be a WSW, we just don't know the precise amounts yet. Link to comment Share on other sites More sharing options...
loudmog Posted December 14, 2020 Share Posted December 14, 2020 I have been a lurker here for at least 5 years, probably more. Nice to see you all jump in, I checked yesterday and didn't see anything yet. After being so badly burned last year, who could blame anyone, haha. 1 Link to comment Share on other sites More sharing options...
Hurricane Agnes Posted December 14, 2020 Share Posted December 14, 2020 The Winter Storm Watch (I initially figured it was for tomorrow and would be converted to a WWA but this was for the Wednesday storm) - Quote Winter Storm Watch URGENT - WINTER WEATHER MESSAGE National Weather Service Mount Holly NJ 715 PM EST Sun Dec 13 2020 DEZ001-NJZ012-013-015>019-PAZ070-071-102-104-106-141200- /O.NEW.KPHI.WS.A.0001.201216T1200Z-201217T1200Z/ New Castle-Middlesex-Western Monmouth-Mercer-Salem-Gloucester- Camden-Northwestern Burlington-Delaware-Philadelphia- Eastern Chester-Eastern Montgomery-Lower Bucks- Including the cities of Wilmington, New Brunswick, Freehold, Trenton, Pennsville, Glassboro, Camden, Cherry Hill, Moorestown, Mount Holly, Media, Philadelphia, West Chester, Kennett Square, Norristown, Lansdale, Morrisville, and Doylestown 715 PM EST Sun Dec 13 2020 ...WINTER STORM WATCH IN EFFECT FROM WEDNESDAY MORNING THROUGH THURSDAY MORNING... * WHAT...Heavy snow possible. Total snow accumulations of 5 or more inches possible. Winds could gust as high as 30 mph. * WHERE...Portions of New Jersey, southeast Pennsylvania and northern Delaware along and near the I-95 corridor. * WHEN...From Wednesday morning through Thursday morning. * IMPACTS...Travel could be very difficult. The hazardous conditions could impact the morning or evening commute. * ADDITIONAL DETAILS...Snow is anticipated to move into the region Wednesday morning and some areas in the watch may mix with sleet and rain. We anticipate there will likely be a sharp gradient in snow totals depending on precipitation type. PRECAUTIONARY/PREPAREDNESS ACTIONS... Monitor the latest forecasts for updates on this situation. && $$ Deal/Gorse/Robertson Link to comment Share on other sites More sharing options...
Heisy Posted December 14, 2020 Share Posted December 14, 2020 7 minutes ago, Hurricane Agnes said: The Winter Storm Watch (I initially figured it was for tomorrow and would be converted to a WWA but this was for the Wednesday storm) - Impressively early. There’s just too much model agreement on the large scale features to not dO it. 1 Link to comment Share on other sites More sharing options...
Animal Posted December 14, 2020 Share Posted December 14, 2020 18z euro buries phl metro! 1 Link to comment Share on other sites More sharing options...
Ralph Wiggum Posted December 14, 2020 Author Share Posted December 14, 2020 2 minutes ago, Animal said: 18z euro buries phl metro! It sure does!! Still has that damn subsidence thing right over my area in Central Bucks. Different than the dry slot we saw progged earlier. This looks like a subsidence zone behind the area of insane frontogenic lifting. Going to be tough to nail that area down. I mean would it matter that much though we are talking the difference between 20" and 13" lol. At this point after the past few years I'm quite happy with a Warning criteria system. 1 Link to comment Share on other sites More sharing options...
Moderately Unstable Posted December 14, 2020 Share Posted December 14, 2020 You know, looking at the model consensus here, 3 days out, I'm really struck by how far forecasting science has advanced in the last 30 years. The fact we can, with some reasonable degree of confidence, say right now, when it's in the high 40s in Philly, that we'll get crushed in the middle of the week by a storm that hasn't EVEN FORMED YET, is pretty dang cool. Everyone always jokes to me that meteorologists have the only job where they're allowed to be wrong. But frankly, when I see stuff like this, it makes me really appreciate all of the professors and researchers and forecasters that have advanced us to this point. Ask a 60s meteorologist to predict this using a paper map of the current weather. Another thing I like about systems like this is, they're not "easy" to forecast per se, but unlike marginal events, where you have to hunt around for tiny kinks in the height lines trying to read the tea leaves, the big systems follow some basic rules vis a vis how strong mid lat systems form and operate, and have clear boundaries, so it's less hair splitting and more actual meteorology. 2 Link to comment Share on other sites More sharing options...
MJO812 Posted December 14, 2020 Share Posted December 14, 2020 1 1 2 Link to comment Share on other sites More sharing options...
jwilson Posted December 14, 2020 Share Posted December 14, 2020 39 minutes ago, Ralph Wiggum said: It sure does!! Still has that damn subsidence thing right over my area in Central Bucks. Different than the dry slot we saw progged earlier. This looks like a subsidence zone behind the area of insane frontogenic lifting. Going to be tough to nail that area down. I mean would it matter that much though we are talking the difference between 20" and 13" lol. At this point after the past few years I'm quite happy with a Warning criteria system. Based on relatively recent history, that area of subsidence seems fairly consistent. I remember watching those bands just to the west of my house (Hatboro) and being dismayed at the near-miss. That was during the last few of these Miller-B hybrid systems. Maybe it's just coincidence. I don't know if there's a climatological or geographical reason for it to happen that way outside of elevation and/or distance from the ocean. Link to comment Share on other sites More sharing options...
ChescoWx Posted December 14, 2020 Share Posted December 14, 2020 I do not see this at all as a Miller B or any type of hybrid B system....there is no primary going up well west with a 2nd low developing on the coast Link to comment Share on other sites More sharing options...
jwilson Posted December 14, 2020 Share Posted December 14, 2020 3 minutes ago, ChescoWx said: I do not see this at all as a Miller B or any type of hybrid B system....there is no primary going up well west with a 2nd low developing on the coast Isn't there a secondary in the Ohio Valley? The trend recently has been to kill it off quite quickly, but at least it used to be there. Also, this might of interest to you guys, but I had no idea there was an 18Z CMC? Is it of equivalent value? You can see the shift in the heaviest axis of precip from 12Z to 18Z, with the latter looking a lot more like the GFS. If this off, I guess we'd find out at 0Z. 12Z 18Z 1 Link to comment Share on other sites More sharing options...
The Iceman Posted December 14, 2020 Share Posted December 14, 2020 16 minutes ago, ChescoWx said: I do not see this at all as a Miller B or any type of hybrid B system....there is no primary going up well west with a 2nd low developing on the coast 1 Link to comment Share on other sites More sharing options...
Birds~69 Posted December 14, 2020 Share Posted December 14, 2020 Just getting around and reading the MA forum. DT rather aggressive for our general area. 70% of 10"+ sounds about right but 40% 20"+ sounds high.....maybe 40% 15"+. Oh well, I'll roll with it... 41F and waiting for model runs... Link to comment Share on other sites More sharing options...
RedSky Posted December 14, 2020 Share Posted December 14, 2020 Kuchera must see it coming down in cats paws clumps to hit these numbers Link to comment Share on other sites More sharing options...
Birds~69 Posted December 14, 2020 Share Posted December 14, 2020 NAM is on a LSD trip.... 1 Link to comment Share on other sites More sharing options...
Moderately Unstable Posted December 14, 2020 Share Posted December 14, 2020 Why is it so strongly set on the inland solution? Link to comment Share on other sites More sharing options...
Ralph Wiggum Posted December 14, 2020 Author Share Posted December 14, 2020 20 minutes ago, Birds~69 said: NAM is on a LSD trip.... That silly model is hell bent on giving us a major sleet event. All by itself it appears. Im fairly certain we can chalk it up to the NAM doing typical NAM stuff at range. If you follow the 500mb vorticity maps and compare with 18z there are improvements until about hour 54 irt slightly better confluence, slower departing hp, and better organization/tilt to the bowling ball coming across the Plains. Then at 54 hrs the surface gets all wonky. By this time tomorrow we should have a classic NAMming under our belts....I thought we were headed there just now until it got whack with the slp placement running into a deeper and better positioned hp. 1 Link to comment Share on other sites More sharing options...
Birds~69 Posted December 14, 2020 Share Posted December 14, 2020 2 minutes ago, Ralph Wiggum said: That silly model is hell bent on giving us a major sleet event. All by itself it appears. Im fairly certain we can chalk it up to the NAM doing typical NAM stuff at range. If you follow the 500mb vortices maps and compare with 18z there are improvements until about hour 54 irt slightly better confluence, slower departing hp, and better organization/tilt to the bowling ball coming across the Plains. Then at 54 hrs the surface gets all wonky. By this time tomorrow we should have a classic NAMming under our belts. Oh yeah, I've been around the block. It's not within range and doing silly things probably till later tomorrow/early Tuesday. Link to comment Share on other sites More sharing options...
Moderately Unstable Posted December 14, 2020 Share Posted December 14, 2020 Well, will be interesting to compare to other short range guidance. Sref etc. I just took a peek at the rpm model, can't post that, but it doesn't have the sleet pocket at the 72 hour mark (end of run). It does have a small sleet pocket over western VA similar to the NAM, but then that line doesn't extend out into PA as the NAM does. Perhaps suggests a potential for a brief period of sleet or ice in a mostly snow event. Definitely does not echo the NAMs craziness though. Link to comment Share on other sites More sharing options...
Ralph Wiggum Posted December 14, 2020 Author Share Posted December 14, 2020 5 minutes ago, Birds~69 said: Oh yeah, I've been around the block. It's not within range and doing silly things probably till later tomorrow/early Tuesday. Every other model is at least 10" here conservatively and the NAM is widespread 1-4" PHL, Delco, Chester, Montco, and Bucks? Ok. Link to comment Share on other sites More sharing options...
Ralph Wiggum Posted December 14, 2020 Author Share Posted December 14, 2020 4 minutes ago, Moderately Unstable said: Well, will be interesting to compare to other short range guidance. Sref etc. I just took a peek at the rpm model, can't post that, but it doesn't have the sleet pocket at the 72 hour mark (end of run). It does have a small sleet pocket over western VA similar to the NAM, but then that line doesn't extend out into PA as the NAM does. Perhaps suggests a potential for a brief period of sleet or ice in a mostly snow event. Definitely does not echo the NAMs craziness though. I wouldn't rule out the mix line getting to my area in Central Bucks but there will be enough moisture to provide snow depth prior to AND after the mix line punches thru then falls back. And that's still an IF the line gets this far N and W. Link to comment Share on other sites More sharing options...
Birds~69 Posted December 14, 2020 Share Posted December 14, 2020 6 minutes ago, Moderately Unstable said: Well, will be interesting to compare to other short range guidance. Sref etc. I just took a peek at the rpm model, can't post that, but it doesn't have the sleet pocket at the 72 hour mark (end of run). It does have a small sleet pocket over western VA similar to the NAM, but then that line doesn't extend out into PA as the NAM does. Perhaps suggests a potential for a brief period of sleet or ice in a mostly snow event. Definitely does not echo the NAMs craziness though. Believe it or not the NAM has had "wins" but it's such an outlier right now. Give it a day it will come around... 1 Link to comment Share on other sites More sharing options...
Moderately Unstable Posted December 14, 2020 Share Posted December 14, 2020 Lol, I believe you. It isn't a crappy model a la no gaps and co, I don't even know if they still run that. So many gaps. Just tends to be wet, over amped, and wild, vs the other contenders. Nam is the place to go if you like things wet and a bit crazy. Sometimes that's a winning combo though. . I mean, the main reason not to buy it, to my non expert eyes, is that it disagrees with everything else. Same reason you don't believe one ensemble member that says 30" when the rest say 3" or vice versa. 1 Link to comment Share on other sites More sharing options...
Ralph Wiggum Posted December 14, 2020 Author Share Posted December 14, 2020 ICON is an improvement. Stronger better positioned hp/CAD...thus colder. Starting to come around to other guidance finally. Link to comment Share on other sites More sharing options...
Birds~69 Posted December 14, 2020 Share Posted December 14, 2020 3 minutes ago, Ralph Wiggum said: I wouldn't rule out the mix line getting to my area in Central Bucks but there will be enough moisture to provide snow depth prior to AND after the mix line punches thru then falls back. And that's still an IF the line gets this far N and W. I'll be a little shocked if we don't hear pings/mix for a short time but minimal...it always happens but changes back to snow relatively quick. Especially as it pulls away... Link to comment Share on other sites More sharing options...
Moderately Unstable Posted December 14, 2020 Share Posted December 14, 2020 16 minutes ago, Ralph Wiggum said: ICON is an improvement. Stronger better positioned hp/CAD...thus colder. Starting to come around to other guidance finally. Could you tell me, where does the ICON rank in terms of performance versus the gfs euro and ukmet for Philly? Not super familiar w/ICON. Link to comment Share on other sites More sharing options...
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