yoda Posted December 2, 2019 Share Posted December 2, 2019 A decent event appears near the end of the 18z GFS run... probably going to be our first real threat of the season if what the EPS/GEFS are suggesting that we have we actually have 1 Link to comment Share on other sites More sharing options...
Scraff Posted December 2, 2019 Share Posted December 2, 2019 9 minutes ago, yoda said: A decent event appears near the end of the 18z GFS run... probably going to be our first real threat of the season if what the EPS/GEFS are suggesting that we have we actually have Feel like the Dec 11-12 time frame might need to be watched too. I like the end of the GFS run as well. Looking forward to your first play by play of the season. 1 Link to comment Share on other sites More sharing options...
WxUSAF Posted December 2, 2019 Share Posted December 2, 2019 4 minutes ago, Scraff said: Feel like the Dec 11-12 time frame might need to be watched too. I like the end of the GFS run as well. Looking forward to your first play by play of the season. If we could get a wave along the tail end of the front that time could have potential. 18z teases that, but the wave is weak and sheared. 2 Link to comment Share on other sites More sharing options...
Bob Chill Posted December 2, 2019 Author Share Posted December 2, 2019 16 minutes ago, Scraff said: Feel like the Dec 11-12 time frame might need to be watched too. I like the end of the GFS run as well. Looking forward to your first play by play of the season. Just be patient. Even though it looks like we go back to bn temps after a nice warm day or 2 next week, pulling an event out of the progressive flow with no block requires a lot of little things to work out. Most importantly tight spacing... Each airmass capable of producing snow will only be in a good spot for 2-3 days tops. Miss that window and the next event is likely rain. It does look like we're moving back into the game mid/late next week. Would be nice if the +pna pattern hangs on for 1-2 weeks so we can get more than one isolated chance at threading the needle 3 Link to comment Share on other sites More sharing options...
Bodhi Cove Posted December 2, 2019 Share Posted December 2, 2019 14 minutes ago, Scraff said: Feel like the Dec 11-12 time frame might need to be watched too. I like the end of the GFS run as well. Looking forward to your first play by play of the season. Bank on it. 8 am flight to Key West on the 12th for a Friday the 13th birthday weekend. Link to comment Share on other sites More sharing options...
Bob Chill Posted December 2, 2019 Author Share Posted December 2, 2019 14 minutes ago, WxUSAF said: If we could get a wave along the tail end of the front that time could have potential. 18z teases that, but the wave is weak and sheared. 18z gefs actually supports the ops idea. Unusual to see qpf panels like this 300 hours out. 3 Link to comment Share on other sites More sharing options...
poolz1 Posted December 3, 2019 Share Posted December 3, 2019 @frd Some positive signs amongst the muddy waters, imo. The propensity for HLB so far has been decent. Nothing sustained.....yet. Aleutian low seems to want to keep forming. No shortage of closed lows traversing the country. No red flags with the strat and if anything signs are positive. I know others have mentioned the MJO and the struggle models are having with it. I think once we get to mid Dec we will see the MJO stopping its flirt with phase 3 and circle back to 8/1. +IOD is coming down but SSTs still showing it plainly...it will have its say. Feeling pretty positive about late Dec and Jan....Though, I feel pretty positive every time before I play golf. Not so much once back to the clubhouse! 2 Link to comment Share on other sites More sharing options...
BTRWx's Thanks Giving Posted December 3, 2019 Share Posted December 3, 2019 Judah Cohen's winter forecast looks pretty good. https://www.aer.com/science-research/climate-weather/arctic-oscillation/ Link to comment Share on other sites More sharing options...
psuhoffman Posted December 3, 2019 Share Posted December 3, 2019 Gfs still brings the cold but this run it buried the pacific system into the Baja so probably just cold/dry. Link to comment Share on other sites More sharing options...
WEATHER53 Posted December 3, 2019 Share Posted December 3, 2019 Still looks good to get those highs rolling in and rolling out to north and not se ridge. Been saying no big warm up and think that holds thru end of month. Link to comment Share on other sites More sharing options...
psuhoffman Posted December 3, 2019 Share Posted December 3, 2019 0z gfs has a happy ending 1 1 Link to comment Share on other sites More sharing options...
ravensrule Posted December 3, 2019 Share Posted December 3, 2019 2 minutes ago, psuhoffman said: 0z gfs has a happy ending Those are the most satisfying. You wait so long and it finally pops a storm. Link to comment Share on other sites More sharing options...
yoda Posted December 3, 2019 Share Posted December 3, 2019 17 minutes ago, psuhoffman said: 0z gfs has a happy ending Really think that time period (Dec 16-19) is going to be our first real threat around here ETA: Actually, is it just me... or did the 00z GFS OP run at the end look like a train of threats headed our direction? Link to comment Share on other sites More sharing options...
yoda Posted December 3, 2019 Share Posted December 3, 2019 00z GGEM has the trailing wave idea but its too late for us... as usual (Dec 11-12) Link to comment Share on other sites More sharing options...
showmethesnow Posted December 3, 2019 Share Posted December 3, 2019 EPS is now fairly strongly picking up on the possibility of a deep dropping PV as well as the potential for a significant cold shot. Below is the run over run changes being seen. Note that we see a significant change in the heights. This is representative of the EPS now seeing lower pressures associated with the pv much farther south then previous runs. Thus we are seeing very significant run over run changes with the 850 temps which are also indicative of a deeper dropping pv. 4 Link to comment Share on other sites More sharing options...
midatlanticweather Posted December 3, 2019 Share Posted December 3, 2019 HM Tweets again reinforcing what is being discussed 3 Link to comment Share on other sites More sharing options...
frd Posted December 3, 2019 Share Posted December 3, 2019 30 minutes ago, midatlanticweather said: HM Tweets again reinforcing what is being discussed Excellent animation by Hugo regarding the upcoming wave break in the North Atlantic. Gives more support to something near mid month. The evolution of any -NAO is still key to an any snow possibilities down our way. By this time we are deeper in December, will be interesting to see what transpires in the NAO domain the second and third weeks of December. Maybe the block times perfectly with some over-running moisture to our South, as signs are for an active STJ this month. Also, note the changes here beyond December 7 th : 00Z GEFS 1.0° 100 hPa 60°N tercile categories The tercile-category anomaly of the lower-stratospheric polar vortex, defined by the 100 hPa 60°N zonal-mean zonal wind, has been used as a diagnostic for the behaviour in the ‘coupling layer’ between the stratosphere and troposphere, i.e. the level in the stratosphere where circulation anomalies are important for influencing tropospheric weather regimes (e.g. Charlton-Perez et al. 2018, Lee et al. 2019). The chart below shows the percent of GEFS members in each tercile anomaly category, based on daily 1979-2018 ERA-5 climatology. Weak = lower tercile; neutral = middle tercile; strong = upper tercile. Link to comment Share on other sites More sharing options...
frd Posted December 3, 2019 Share Posted December 3, 2019 Most excellent ! I totally agree, minute details in weather do matter, that is what makes this hobby so enjoyable. Next, I need snow, a lot of it please. I want to dust off the snowshoes. Link to comment Share on other sites More sharing options...
frd Posted December 3, 2019 Share Posted December 3, 2019 More on the possible NAO block from HM and his general thoughts about December. Great job so far Anthony ! Colder risks seem to be gaining traction lately. 3 Link to comment Share on other sites More sharing options...
poolz1 Posted December 3, 2019 Share Posted December 3, 2019 That post by Webb is a prime example of why trusting ensembles right now past D10 is risky. In 4 days it goes from CONUS torch/Pac flood to a nasty Arctic outbreak. 2 Link to comment Share on other sites More sharing options...
frd Posted December 3, 2019 Share Posted December 3, 2019 3 minutes ago, poolz1 said: That post by Webb is a prime example of why trusting ensembles right now past D10 is risky. In 4 days it goes from CONUS torch/Pac flood to a nasty Arctic outbreak. You know avoiding a massive and prolonged warm up in Canada, along with a loss of snow cover, similar to last December, in my opinion really ups the ante for severe arctic outbreaks here in our area. Snow cover to our North and Northwest is very impressive right now. 2 Link to comment Share on other sites More sharing options...
Bob Chill Posted December 3, 2019 Author Share Posted December 3, 2019 30 minutes ago, poolz1 said: That post by Webb is a prime example of why trusting ensembles right now past D10 is risky. In 4 days it goes from CONUS torch/Pac flood to a nasty Arctic outbreak. Webb jumped on the ens too quick. That look was fleeting and sporadic and not a building signal. There were plenty of conflicting signals at the same time but Webb wanted to be first to call the torch. 8 Link to comment Share on other sites More sharing options...
Bob Chill Posted December 3, 2019 Author Share Posted December 3, 2019 I generally look at the height fields and not numerical indices but the graphs are telling us something... Every major teleconnection has been zig zagging (that's a technical term) since mid Nov. There is no stability or persistence with long wave features. You know what that tells me? It tells me not to make any fast decisions/predictions about anything. Looks like we have building consensus for a +pna/-epo/+nao period coming up. That's enough to keep us in the game but the game will be difficult to win. Beyond that? Good luck guessing. 2 Link to comment Share on other sites More sharing options...
Bob Chill Posted December 3, 2019 Author Share Posted December 3, 2019 Digging back through the last week or so of ens runs, one thing does stand out with the EPS. The EPS has had multiple false signals of having a trough dig into the GoA or west coast in the long range. The GEFS/GEPS have been more consistent in showing more of a +pna and/or -epo building. Could be the MJO forecasts or it could be some sort of inherent bias. Don't really know the whys but the GEFS/GEPS appear to be verifying better d10+ in the Npac versus the EPS. Something to keep in mind when comparing ens runs in the LR. 1 Link to comment Share on other sites More sharing options...
Eduardo Posted December 3, 2019 Share Posted December 3, 2019 9 minutes ago, Bob Chill said: Digging back through the last week or so of ens runs, one thing does stand out with the EPS. The EPS has had multiple false signals of having a trough dig into the GoA or west coast in the long range. The GEFS/GEPS have been more consistent in showing more of a +pna and/or -epo building. Could be the MJO forecasts or it could be some sort of inherent bias. Don't really know the whys but the GEFS/GEPS appear to be verifying better d10+ in the Npac versus the EPS. Something to keep in mind when comparing ens runs in the LR. Great points here! Have the GEFS/GEPS also performed better on the MJO front, in fact? If so, then that's probably the best explanation for their better verification up-top. Link to comment Share on other sites More sharing options...
UniversesBelowNormal Posted December 3, 2019 Share Posted December 3, 2019 The +PNA without +ENSO subsurface is suspect (days 4-8) Major +NAO in December could be ramping up for major -NAO January, and Stratosphere warming in the wave Link to comment Share on other sites More sharing options...
frd Posted December 3, 2019 Share Posted December 3, 2019 I will take an order of blizzard, a side of drifts and for dessert a gale or two. 4 1 Link to comment Share on other sites More sharing options...
UniversesBelowNormal Posted December 3, 2019 Share Posted December 3, 2019 ^We can't get classic -NAO Link to comment Share on other sites More sharing options...
Bob Chill Posted December 3, 2019 Author Share Posted December 3, 2019 8 minutes ago, Eduardo said: Great points here! Have the GEFS/GEPS also performed better on the MJO front, in fact? If so, then that's probably the best explanation for their better verification up-top. I honestly don't worry about the MJO much unless it's an amplified wave in the crappy sectors. Since mid Nov it's been either a weak signal or in the COD. Ens have been agreeing on a weak trip in phase 2 and back to the COD and that's been going on for most of the last week although I don't check every day. Just a quick scan once in a while so my MJO obs could be flawed. The AO flip was well modeled by all ens and even ops. It's almost a lock that the east gets at least a brief warm period after the AO flips positive and that appears to be verifying over the next week or so. Back when the AO flip was first showing consensus it looked really ugly but thankfully that's backed off and the current +AO flip appears to be short lived and inconsequential in the bigger picture. The nPac appears to want to play nice and that's the best way to avoid a +AO shutout/torch. 2 Link to comment Share on other sites More sharing options...
psuhoffman Posted December 3, 2019 Share Posted December 3, 2019 QBO for November came in at 5.07. Looking at the progression the closest matches to this year are 2004, 2002, 1997, 1978, and 1969. Of those the best match purely on QBO continues to be 2002 with the last 3 months all being nearly identical. Of the 15 winter months those years the AO was negative 12/15 months. The only year of those that didn't feature a -AO for 2/3 months was 2004-5 but it is notable that year started with an extremely +AO and flipped mid January. There were 2 other years that were somewhat close, 1955 and 1961. If we include those the AO was negative 17/21 months. 4 Link to comment Share on other sites More sharing options...
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