Roger Smith

It's a weather thread, a travelogue and a place to get spiritual counselling. I hope the GFS sees the error of its ways and repents.

I blew up my screen mag to the max and the ICON track is about 50s.e. RIC to 50e BAL to TTN to EWR. The pressure is falling steadily into the 980s by about PHL. It does not look perfect for everyone but something to hope for in terms of GFS/GEM backtracks later on, we hope. One of the moving parts that evokes less than perfect trust here is the arctic high, it is a puny thing at present, just 1020 mb over Thomson MB, and while -38F sounds frigid, that is not exceptionally cold for the location near center of high pressure at 0700h local time. Which makes me wonder if the thing can ever reach 1036 mbs let alone low 1040s. I suppose if it was really weak it might have to push down behind the vortmax instead so there is that.

12z ICON has the thermal gradient intruding for a few hours into e MD but holds the cold air in place for areas nw of DC, not ideal but similar to the last run of the ECM now. The 500 mb low tracks almost overhead and towards NYC. Would say it's 8-16" for some parts of noVA and w MD, 4-8" for DC and BAL with full transition to rain followed by wrap around flurries. Anyway there is a lot of time left, the first storm hasn't even materialized yet, let alone this one.

meteociel.fr tres rapide

12z ICON is about six hours slower than previous run and has moved slightly towards the ECM but it still looks okay for a good part of the region (at 114h). Track is now something like New Bern to SBY to TTN to NYC

Let the sorcery begin, a thousand weather wizards all chanting Quebec high coastal track max the cold confine the warmth. All hail King Euro and Prince Icon. And Baron Ukie. A plague be upon you, GEM and GFS. The wizards of wPA have a much different chant. Off with their heads.

The cold looks less extreme on more recent model runs than when I posted, so maybe the values shown will be too cold now. Reality could be closer to -2 in the east and -5 for Chicago if the cold is just mundane. We have to get the eastern locations below normal first, then see how sustained the cold trend really proves to be. Your numbers look pretty good in general, especially in terms of relative scoring. (that is by the way against the law in 37 of the 50 states and most provinces of Canada)

Arnt you suppose to call for 22-28? Might be better if I call for heavy rain.

UK OK ... coastal and good snow potential. Over to EURO but anything could happen here, we're dealing with some rather weak building blocks that all have to balance perfectly for any solution, including the bad ones.

The GGEM looks a bit better than the GFS but not much and doesn't quite catch fire. Not sure if your discussion about ICON has seen the 00z run early or still waiting to see it? I saw it on meteociel and it looks good. Track is coastal. Problem with ICON is that it tends to go to various extremes and unless the outcome is extreme that makes it unlikely to verify. But you can always hope. Bit of a blind man's bluff at this point, working with some very weak signals that have ways of producing a good storm. Would not toss at this early stage.

Get greedy. Retrograde the whole pattern and get the ocean storm too. There's no limit to optimism, pessimism has the lower bound of zero unless maybe one could visualize negative snow.

They call the 18z GFS the pub run in the UK. Apparently this one is a tavern run.

Have just edited in some second place temperature finishes for Dec 2021, weeks of 10th-16th to 12th-18th. While 2021 was unable to match 2015 for those weeks, it did move into second place for all three on mean maximum and mean daily, just the middle one of the three for mean minimum. The values can be seen in the December post back in the thread, but are basically around average highs of 58F and mean daily 50F, but in the vicinity of six degrees short of the 2015 record values, about 1-2 F above the previous second place values from years such as 1984 and 2006 (for those weekly intervals). Working on the record weekly snowfall amounts now. Will post those in about a week or so (maybe after the weekend storm does its thing).

That NAVGEM offering when applied to weighted model consensus means a 15 mile shift to the east and 0.5 mb deeper. Not a bad thing. Pros don't always go on weighted model consensus, they sometimes pick a favorite or a consensus of two that they think have the better handle. But when a lot of models are showing very similar outcomes, a weighted model consensus often outperforms any one model taken alone. A good rule for the weighting might be 30% GFS, 25% Euro, 15% UK, 15% GGEM, and when time scale permits, 15% NAM. Go with RGEM instead of GGEM whenever possible. Ignore ICON and JMA. NAVGEM differentials are probably not that significant but if you wanted to give it 5% then if it's 300 miles east, that vector is 15 miles east. If it's 10 mb deeper that's 0.5 mb.

I think any attempt to track inland will play out as a double-centered tucked storm, the 500 mb evolution does not support much inland movement of mild air, but of course the North Atlantic is remarkably warm just offshore too, whether that remains true after the earlier storm comes and goes through the Gulf of Maine remains to be seen. My numbers are based on this model consensus for rapid or explosive deepening verifying, if later model runs back off that idea then I would withdraw those numbers. Snowfall rates of 3-4" an hour are possible with that kind of explosive development. But I do anticipate a large gradient as I said, a lot of the NYC metro could see mixing so snowfalls might be around 9-15" for many, 15-24" across parts of n NJ and Yonkers-White Plains, 24-30" further north and west. It would come down for about 24h at 1-3" an hour in some places (if these early indications prove correct). Would say there is more potential for the eventual track to be east rather than west of what is now shown, a certain amount east is good in general for snow potential, especially with similar rapid development. Blizzard of Feb 1899 not that different an evolution from what I can see on historical maps, of course the depth of inland cold air greater and probably the Atlantic not as warm, but track is quite similar. That storm gave NYC 16" and DC 20" (in the city rather than at DCA location now). Some similarity to 93 storm but can't see this tracking into the Hudson valley or even New England as the 500 mb low tracks northeast rather than north-northeast or north. Anyway, exciting winter compared to how it was looking in December. Like the grips guy says on the golf commercial, feels good huh?

The larger scale picture does not fit the scenario of a strong push of mild air inland, my hunch is that in the explosive cyclogenesis phase which appears likely near the Delmarva, the eventual shape of this storm will be double-centered with a triple point near the Texas Tower moving northeast to Nantucket. It could allow a blizzard to develop in many areas and confine the mixing zone to eastern LI and perhaps right along the coast to JFK, and down the Jersey coast to ACY then into the Delmarva. Could be a very large snowfall gradient across the NYC metro as a result. Potential for 24-30 inch snowfalls with this, most likely location would be n NJ, lower Hudson valley, w CT into central MA. (and further south in parts of e PA, w MD, n VA).

With the explosive cyclogenesis factor, this would produce extreme snowfall rates over the region and the frontal boundaries might not be as far inland as feared because of the rapid development. Also would expect a correction on this westward trend as chinook signal is filtered out of the development (chinooks confuse models a bit as there is warmth that won't travel downstream). The genesis for this storm is the short wave moving inland over the Pac NW and then due to sneak through the upper level ridge out west to form a Rocky Mountain lee depression in se CO that generates low pressure in Texas. The key is the strength of the arctic high moving southeast to wedge between this storm and the previous one which would be up around Baffin Island by Sunday. As that crests ahead of the bombing east coast cyclone, cold air will be hard to push out, if the 985 mb low verifies but closer to a track up the coast and towards east half NYC metro, then sleet stays coastal - Delmarva and S+ axis is closer to I-95 although still somewhat further inland. Blizzard of 1899 followed a similar evolution and crossed n FL, came up the coast and bombed out near Delmarva. Depth of cold air not quite up to that standard and more similar to the Blizzard of 93 which also came across ne FL. Something big is in the works and the timing at full moon brings in a lot of strong analogues. This could easily top 30" somewhere in the subforum, most likely sw to nw of DC. Would say 8-12" DCA and 15-20" IAD, 10-15" BWI, mostly sleet to rain SBY, multi-phase crapfest RIC, 2" rain se VA. Thundersnow and thundersleet very likely.

How about Full Moon Freeze Fest Spectacular? I had a dream too.

You learn a lot here, I never knew there was a Buffalo in Maryland.

Anomalies and projections ... ________________________ DCA _ NYC _ BOS __ ORD _ ATL _ IAH ___ DEN _ PHX _ SEA ____ (10d anom) _______+0.5 _ +1.0 _ +1.9 ___ -7.1 __+4.3 _ +3.0 __ -5.5 _ -1.1 __ -3.6 ____ (20d anom) _______-0.6 _ -0.8 _ -0.4 ___ -3.1 __+1.6 _ +1.4 __ +0.2 _+1.0 __ -0.7 11th__ (p20d anom) ___-3.0 _ -2.5 _ -2.0 ___ -8.0 __ 0.0 _ +2.5 __ +1.5 _ +2.0 __ 0.0 11th__ (p27d anom) ___-4.0 _ -4.0 _ -4.0 ____ -9.0 _ -2.0 _ 0.0 ___ +2.0 _ +2.5 _ +1.0 21st __ (p31d anom) __ -2.0 _ -2.0 _ -2.0 ____ -4.0 __ 0.0 _ 0.0 ___ -1.0 _ 0.0 __ +0.5 30th __ (p31d anom) __ -2.5 _ -3.0 _ -2.5 ____-5.0 _ -0.5 _-1.0 ___ -1.0 _ +1.0 _ -1.5 end of month anom ___ -2.9 _ -3.4 _ -2.5 ____ -4.6 _ -0.3 _ -1.0 ___ -0.8 _ +0.9 _ -1.8 (see previous post for updated snowfall totals) 11th _ The month started very mild in the east which is why the anomalies are still holding on to small positive values after ten days but basically the pattern changed around the 3rd and has remained rather cold since then, and is about to get even colder, with the last third of the month looking even colder. That cold air may eventually spill down to the Gulf coast and as we learned last February, a few days in the deep freeze at Houston can wipe out a significant positive anomaly very quickly, so I have tentatively dropped the projection to zero by the 27th but if that cold air fails to reach IAH then it could be closer to +3, if the outbreak is severe for 4-6 days than it could be -3.0 very quickly. ORD never gets much of a break from the cold but SEA is quickly coming out of the deep freeze and should eventually get to positive numbers. DEN had some deep cold for a few days but has flipped to very mild and could push past the conservative +2.0 that I show here. Nothing very simple about this pattern, but historic cold appears to be heading for the east after the end of this week which will produce a couple of near normal days before the cold arrives. 21st _ The colder trend was weaker than expected for the east but the milder trend was about as predicted in the west. This has left most locations with small negative anomalies to the 20th. Another cold spell looms for the east so the projections there go back below normal. DEN looks to be in a variable regime with some quite cold days keeping the average close to normal there. SEA will continue a slow rise towards an outcome just above normal, possibly. Snowfall amounts to date were updated in the previous post. Only BUF has had a heavy snowfall so far and SEA has not added to its impressive earlier totals. 30th _ Snowfall totals updated after the big storm yesterday (in the northeast). DEN and ORD have been adding some significant amounts too. Also, a new set of provisionals is available, so that scoring below can be updated. These new provisionals will be converted into the final values by mid-day Tuesday 1st. 31st _ Preliminary final anomalies have been posted from known data including the 31st, these will be adjusted when finalized, and then scoring will be adjusted (so I don't do the same thing twice, the scoring you see as of now is based on the earlier provisionals -- these new ones may change the scoring order a bit here and there). 1st __ Final anomalies posted, scoring is final.

GFS looked promising to me, for day 7, and the Euro looks way too slow with the first low which is likely to be much further northwest into the Baffin Island region by day 6 not lingering off Labrador. There's almost zero storm potential on the Euro-CMC consensus but just one turn of the dial away from a good outcome on the GFS. Some ensemble members have that turn of the dial. Two factors may help. One is that low pressure connecting back from the arctic remnant of the first storm to the Great Lakes could drop an energy center into a good spot by day six. Another is that full moon is on Jan 17th. This brings several good analogues into play. I would look for gradual trending of all guidance towards a big storm in the region on Jan 17-18.

It must be the effects of climatology change.

The 2021 data have all been entered into the supporting excel files and new versions are now available at Net-weather. Scroll back to the first post in this thread for the link and look for the most recent post in the linked thread. 2021 was tied third warmest on record for Toronto in this data set, and remained near that level even when earlier years were given the advantage of an urban heat island upward adjustment. NYC was closer to 8th warmest (the official data have not been confirmed, going by the monthly averages the year is around 8th) and once again, earlier years do not push in despite a boost; the recent warmth is somewhat more than just the urban heat island so it is tending to keep the raw data and adjusted data similar near the top. Less prolific warm months such as July 2021 sink down a bit in the adjusted data. While NYC had quite a wet year (10th wettest of 153) Toronto was much closer to average. The same trends were in evidence except that Toronto had a very dry August (NYC had excessive rainfalls from late August into early Sept after quite a wet July, and October was also rather wet). The fact that Nov-Dec 2021 turned dry at NYC prevented the year from overtaking 9th and 8th place years which would have happened with just normal amounts of precip in the last two months. Although it was generally quite a warm year, records were not unusually frequent, and there was one notable cold event at the end of May with some record low maxima set (unusual in this era) as well as very late traces of snow at Toronto (snow fell in small measurable amounts outside the city around May 29th). The data files in this thread have been largely brought up to date now with 2021 ranks inserted. The Net-weather thread has some additional record high min data for years 1869-1900 at NYC, which I won't edit in here because the next step will be to post a more user-friendly log of these as they change through time, but if anyone is interested in reading the material it can be found in the Net-weather version of this thread for NYC years 1869 to 1900. (once again, if you're a first time visitor to this thread, go to the original post and you'll see why there is a link to Net-weather, the excel files are too large to upload here)

George BM has higher forecasts than any other player in all four locations. I took numbers that were just slightly higher than 2nd highest forecasts in general, and found the following: I started with values equal to second highest forecasts and checked each forecast that was among the top five. Those are the five who need more snow than me, and they are generally in a zone where they need quite a bit more. Anyway, at that first level, ldub23 (second highest totals) easily wins over the 3rd to 5th highest, he has two of those second highest numbers, another is just 1.0" under, and for RIC ldub23 is 4" under second highest. So it would appear to be a straight up contest between ldub23 and GeorgeBM if more snow than ldub23's forecast materializes. Therefore the amounts GeorgeBM would need would be any combination of smaller errors, which could occur with four cases where he is 0.1" or more ahead, or various other combinations. If all the errors were equal, then he would need 32.6" more at BWI, 20.3" more at DCA, 39.2" more at IAD, and 23.5" more at RIC. Those are season totals of 42.4" BWI, 29.9" DCA, 47.6" IAD and 25.5" RIC. You could jog those around, as long as the four totals add up to at least 145.4" then GeorgeBM could win.

On the subject of the BWI 6.8 or 6.0, they still say 6.8 in the CF6 product also. It is not without precedent for a value in the CF6 to undergo later changes, so worth keeping an eye on that detail. Looking at the current standings, it is interesting that the first forecast in the current rankings with a higher forecast for DCA than snow already measured is 12th (and they have only 0.2" to use up) and the next after that is in 27th place. This would be reduced somewhat if we counted only the ranked forecasts that were not eliminated (those that can only sink lower in the standings now). Also of interest is that of the first twelve forecasts including that first one that could benefit from DCA snow, only three can benefit from further snow at BWI. Another very moderate event such as 4" BWI and DCA 5" IAD and 3" RIC would move the lead down to current 27th place IUsedtoHateCold with 28th place RodneyS then second with 30th place Weather53 in third. Looking at current departures, most people in that part of the table have the makings of one plausible snowstorm, while people down near the bottom have a requirement for one large storm or two moderate ones. My residual snowstorm is 13.7" BWI, 8.6" DCA, 18.2" IAD and 12.8" RIC. But I would settle for two that added up to that.