December 2019 Med/Long Range Disco

[CAPE]

Improving look in the NA in the LR on the 18z GEFS. Weak ridging over GL with a 50-50 low. Xmas eve eve.

[AmericanWxFreak]

Euro looks goodish for midweek 

[WxUSAF]

1 minute ago, AmericanWxFreak said:

Euro looks goodish for midweek 

18z euro is quite good apparently and snowing at the end of the run

[MillvilleWx]

3 minutes ago, WxUSAF said:

18z euro is quite good apparently and snowing at the end of the run

Tis quite solid. 

[CAPE]

4 minutes ago, WxUSAF said:

18z euro is quite good apparently and snowing at the end of the run

Looks a heck of a lot better than 12z.

[Weather Will]

There seems to be an interesting dynamic going on in the form this year or tension since so many have called for s torch in December and that may or may not verify.  To be fair, I have not heard or seen anyone calling for a snowy December so expectations should be very low.  Would take the 18Z EURO in a heartbeat.

[NorthArlington101]

10 minutes ago, losetoa6 said:

Ensembles back the Euro  op up for Wed  . Lots of nice hits  . Big shift from 12z 

Just to back this up with maps:

12z:

18z:

[jaydreb]

I can extrapolate a good hit from this.  Snow in Alabama and Mississippi can’t be a bad thing. 

Edit: Posted 18z.  0z is even better.  

[yoda]

3 minutes ago, jaydreb said:

I can extrapolate a good hit from this.  Snow in Alabama and Mississippi can’t be a bad thing. 

That's 18z... 00z is just finished and looks decent at 84

[yoda]

3 minutes ago, losetoa6 said:

Nam joins the party 

Looks somewhat similar to the 18z Euro 

[WinterWxLuvr]

NAM always joins the party.

Super accurate at 84 too

[WinterWxLuvr]

9 minutes ago, WxWatcher007 said:

There’s only one thing we can do at a time like this:

LOL that had to hurt

[psuhoffman]

37 minutes ago, losetoa6 said:

The thing is many ensembles are real juiced . It wouldn't surprise me if a thin swath of moderate totals like 3-6" 4"-8" comes out of this in the end but a long way to go and tight margins most likely for the winners vs losers.  I'm leaning i81 corridor. 

People question these frontal wave setups all the time but they can work. Problem is because they are discreet waves in a progressive pattern they are incredibly finicky and hard for guidance to pin down with any accuracy at range. So when they are on guidance at day 7 or 10 there is very little chance they will be right. Either there is no wave or the boundary isn’t located exactly right at that lead so it’s somewhere else.  We’re getting close enough to start taking it seriously but there will be adjustments and shifts even within 48 hours with these. Anyone who says they know what is going to happen is full of it.  Slight adjustments in the timing, press of cold, and amplification are the difference between rain, snow, and a squashed wave.  I feel like we’re in the game but I won’t feel confident about a setup like this until very short range. That’s why people “think” they never work. When they do we usually didn’t see them coming. When we see them from range they often don’t. 

[jaydreb]

GFS is pretty good for areas N & W.  Just a touch too warm for DC Metro but time for things to change.  

[Ji]

2m temps are blowtorch 

[psuhoffman]

Interesting developments wrt the high latitudes on tonight’s ops and not forever out in time either.  Definitely need to watch this for a possible phase change in the AO NAO which would seriously change the calculation for snow in the current pattern in our favor. 

[NorthArlington101]

EURO held pretty steady. Ens lost a little enthusiasm but 18z had some big hits so I’m not shocked the mean dropped off a bit.

[showmethesnow]

06Z has the same general distribution with snowfall (Kuchera) as we saw on the overnight run though totals are slightly less. Generally a 2-6" event through the DC/Balt corridor with the higher amounts N/W of the cities.

[Weather Will]

6z GFS. Kuchera WB.  My take as of now is that since day before will be in the 60s and sUrface temps Wed morning just around freezing NW of DC,  BA, this will be white rain inside the Beltways, and a grass coverer if we are lucky NW.

[Ralph Wiggum]

10 minutes ago, Weather Will said:

6z GFS. Kuchera WB.

Snow depth maps are usually a more accurate depiction and I say this seriously. Not always, but usually. Many would take this and enjoy the Hallmark scene and cardinals flying around look.

[CAPE]

1 hour ago, showmethesnow said:

06Z has the same general distribution with snowfall (Kuchera) as we saw on the overnight run though totals are slightly less. Generally a 2-6" event through the DC/Balt corridor with the higher amounts N/W of the cities.

Looking at all the latest runs, in general the best forcing for a longer duration looks to occur NW parts of the region, so even with marginal surface temps a few inches may accumulate. The fall line and points SE have some work to do, with temps mostly mid 30s and maybe not getting the best rates either. That's not a good combo, but it could change(might get worse lol).

[PDIII]

8 minutes ago, Ralph Wiggum said:

Snow depth maps are usually a more accurate depiction and I say this seriously. Not always, but usually. Many would take this and enjoy the Hallmark scene and cardinals flying around look.

That looks about right.. I would just make the white spot about 10 miles larger in diameter and put one of Baltimore too

[Weather Will]

20 minutes ago, Ralph Wiggum said:

Snow depth maps are usually a more accurate depiction and I say this seriously. Not always, but usually. Many would take this and enjoy the Hallmark scene and cardinals flying around look.

I would take it in a minute!

[poolz1]

It seems that models are waffling on how much energy is pulled out of the southern piece.  Slight changes are the dif between snow tv, coating-2" or a nice 2-4/3-6...

To add to PSU's post above....

[frd]

9 hours ago, psuhoffman said:

Interesting developments wrt the high latitudes on tonight’s ops and not forever out in time either.  Definitely need to watch this for a possible phase change in the AO NAO which would seriously change the calculation for snow in the current pattern in our favor. 

I see a noticeable AO ensemble change with today's forecast, a decent majority of the members take the AO to neutral to even negative by mid-month. This is a rather big change in the last 24 hours.  

 

[CAPE]

CFS has a much improved look for the rest of the month compared to what it had been advertising previously. Supposedly it is pretty accurate in this range, and it aligns with what we are seeing on the global ensembles. Pretty cold look here for week 3 of December.

Potentially active too with a split flow and hints of lower pressure in the SW.

[frd]

20 minutes ago, C.A.P.E. said:

CFS has a much improved look for the rest of the month compared to what it had been advertising previously. Supposedly it is pretty accurate in this range, and it aligns with what we are seeing on the global ensembles. Pretty cold look here for week 3 of December.

Yes, this is in the CFS's wheelhouse. The intriguing  part though is the time period, December 22nd  to the 29 th. 

Looking at the MJO convection and the expected progression , along with the various indices, especially the  EPO region, it looks as if we lose the -EPO due to the MJO progression, at the same time the AO and even the NAO regions improve. This all takes place between the 9 th and the 16 th. 

The CFS here is implying a shift to the colder outcome later in the month.  So, maybe we warm prior to Christmas,  as we have every year for the past 8 years and then the pattern becomes favorable again. This would match some analogs.   I can buy this outlook with the assumption that the CFS is seeing through the moderation period.   

[Bob Chill]

A lot of signs on the ens that we lose the Pac in a couple weeks. Not saying I think we flip warm and stay there but it sure looks like (to me) a relax is coming for north america in general. 

[frd]

2 minutes ago, Bob Chill said:

A lot of signs on the ens that we lose the Pac in a couple weeks. Not saying I think we flip warm and stay there but it sure looks like (to me) a relax is coming for north america in general. 

 

I know this is speculation, however, do you think the CFS is seeing beyond the moderation period with the outlook that CAPE just posted  ? 

 

 

[WxUSAF]

8 minutes ago, Bob Chill said:

A lot of signs on the ens that we lose the Pac in a couple weeks. Not saying I think we flip warm and stay there but it sure looks like (to me) a relax is coming for north america in general. 

Lol, just as the pole and Atlantic look to shift better, the Pac wants to take a crap. I’m still skeptical until it happens since this has been advertised a few times in the last 6 weeks only to either not happen or be very transient.