December Medium/Long Range Discussion

[bncho]

i would wait to call 12/2-3 dead until the nov 30 storm happens. 36 hours out from then and there's still lots discrepancy between models. indy doesn't know whether they're going to get 8 inches of snow or just plain rain rn

[WEATHER53]

That high  running off Maine just as it starts is no good for 12/2.  
Further west  by 350 miles is needed

[mitchnick]

[mitchnick]

Euro is a N&W event similar to map above.

[Weather Will]

WB 0Z ensembles for early next week:

[TSSN+]

6z euro still looks on for northwest crew. 
 

 

[stormy]

6 hours ago, WEATHER53 said:

That high  running off Maine just as it starts is no good for 12/2.  
Further west  by 350 miles is needed

100% correct. 

Possible, but the 12-2 system has the deck stacked against it. 

No 50-50 low,  no Lakes to New England H.P. as a cold air source.

And of course, our long time drought pattern that no one fully understands is again an aggravating factor.  The GFS dropped the QPF from 1.48" for Augusta at 06  11-27 to .60" at 06  11-28.  I don't have enough fingers to count how many times this has happened during the past 4 months.   

[WxUSAF]

33 minutes ago, TSSN+ said:

6z euro still looks on for northwest crew. 
 

 

Fall line event makes sense for climo in early season

[Terpeast]

Small bit of good news - cold is overperforming. For the midwest storm, their forecasters shifted their maps a tick south.

[mitchnick]

7 minutes ago, Terpeast said:

Small bit of good news - cold is overperforming. For the midwest storm, their forecasters shifted their maps a tick south.

We'll take anything we can get.

[winter_warlock]

Which is more accurate. Euro control. Or Euro AIFS? 

[87storms]

GFS vortmax is further north than we'd want based on "my lack of formal training" experience.  Euro is further south, but still not completely ideal.  That's been a trend for the last couple years...northern stream is either too far north or flatting the southern stream.  At this point, I just want a storm that reminds me that we can in fact get a southern stream dominant wave that drops an inch of precip over the region.

[WVclimo]

06Z GFS looks pretty slick out this way Tuesday morning. 0.75” FZRA.  A lot of it with temps 29-30°

 

[frd]

The AO remains positive, but we have intense cold in Canada and a weak PV. 

The MJO and the general progression could show potential Dec 15 th to Jan 5 th for the East Coast. 

>>>

 

 

 

 

 

[Eskimo Joe]

Good to see the MJO crawl through Phase 7, 8, 1. The other year it damn near blasted through over 4 days. 

[Terpeast]

9 minutes ago, Eskimo Joe said:

Good to see the MJO crawl through Phase 7, 8, 1. The other year it damn near blasted through over 4 days. 

Yeah, if it rockets through the cold phases, it won't do anything for us. A slow crawl hugging COD would extend cold risk for us.

[frd]

12 minutes ago, Terpeast said:

Yeah, if it rockets through the cold phases, it won't do anything for us. A slow crawl hugging COD would extend cold risk for us.

I believe @GaWx had a detailed post about the benefits of a favorable phase(s) closer to the COD,  versus high amplitude. 

 

[mitchnick]

Icon isn't great, but it has creeped further south making it a lot closer than 0z and 6z.

[MillvilleWx]

58 minutes ago, frd said:

The AO remains positive, but we have intense cold in Canada and a weak PV. 

The MJO and the general progression could show potential Dec 15 th to Jan 5 th for the East Coast. 

>>>

 

 

 

 

 

That's not a bad look for the MJO if that were to materialize. Having it decay in Phase 8 and enter the COD opens the door for more prolonged cold and semi-active periods. Hopefully this is a sticky forecast. 

[TSSN+]

43 minutes ago, mitchnick said:

Icon isn't great, but it has creeped further south making it a lot closer than 0z and 6z.

Think we sneak out something but how much tbd 

[bncho]

EPS signals that we still have lots of chances after Dec 2.

[TSSN+]

CMC like here’s something different 

 

 

[TSSN+]

Actual ends up like euro at 6z

 

[MillvilleWx]

22 hours ago, MillvilleWx said:

AIFS and ECWMF are in closer proxy to each other wrt handling the 5H pattern. A little flatter and confluence better for here, however the HP to the north isn't as pronounced compared to GFS/CMC which would play a role into the antecedent airmass domain the storm would attack. Guess is the GFS/CMC are too amped at the moment and will likely shift closer to the AIFS/ECENS combo. This has climo, fall line type event written all over it. Early in the season for the lowlands.

Mentioned this yesterday and I haven't wavered on this forecast yet. I feel any wintry precip in the region will be confined northwest of the fall line. The key is the timing of the HP movement to the east and the the low attack. A few days ago, we had a little more stay in the HP to the north which would offset some of the warm advection from prevailing southeast flow and provide a deeper wedge to break through. Now the high is shifting east and in a classic spot for a positive u-vector wind anomaly to take shape earlier, eroding CAD prior to approach of the main precip field. Magnitude of cold is subjective, so it's plausible the wedge is deeper than advertised from the preceding pattern, or the low isn't as robust and doesn't have the stronger boundary layer WAA regime materialize making it easier for the cold to remain. The fact stands that the current forecast would yield little wintry precip for the lowlands and is shaping to be a classic elevation/longitudinal type pattern for the area. Further north and west, the better the chance. EC AIFS and AIFS-ENS are still in pretty good agreement on some low-end threat for snow/sleet prior to the setup yielding all rain for the area. Would need a massive shift in the HP to the north about 200-350 miles further west as @WEATHER53 alluded to in a recent post. Still super early in the season, so it's just nice to have something trackable at this point instead of watching temps in the 50s and 60s and swatting mosquitos into December. 

[Ji]

GFS did tick south from 00z

[Weather Will]

WB 12Z GEFS is better for NW burbs. Some nice hits....

[mitchnick]

6 minutes ago, Ji said:

GFS did tick south from 00z

Personally feel that'll be the trend in keeping with the season. How far, who knows. Still think we're all in the game, but odds do favor N & W like 80-90% of all snow chances around here.

[TSSN+]

Ukmet pretty shredded system still gives far nw 2-3” but it looks nothing like gfs or cmc. 

[mitchnick]

Just now, TSSN+ said:

Ukmet pretty shredded system still gives far nw 2-3” but it looks nothing like gfs or cmc. 

A weak p.o.s. is on the table imho. Without a stronger higher, the cold air will give up on the fight easier and we'll lose lift. So I'm not feeling locked in on any scenario at this point.