November Medium/Long Range Discussion

[Weather Will]

The big story for early next week will be the shot of cold air.  Let's hope it is a sign of things to come.   Seems like last several years it took forever to get any cold air into the mid Atlantic. WB EURO Tues am. apparent temps  and anomalies... time to drain the outside spigots.

[bncho]

on the bright side, however, 12z EPS shows a decent signal (albeit slightly less than last 12z), showing 29 out of 50 (58%) hits for at least one of the four airports.

 

[Interstate]

16 minutes ago, Weather Will said:

The big story for early next week will be the shot of cold air.  Let's hope it is a sign of things to come.   Seems like last several years it took forever to get any cold air into the mid Atlantic. WB EURO Tues am. apparent temps  and anomalies... time to drain the outside spigots.

There is no way I get into the teen and Baltimore gets to 20 degrees.

[Eskimo Joe]

 

 

[bncho]

my wag at next week, west has a better chance of accumulation (obviously) and South of DC is favored to see some flurries (if anything manages to happen there).
 

[Ji]

Mark Margarbage on twitter using the CFS to try to justify a snowstorm in a few days

[Weather Will]

25 minutes ago, Interstate said:

There is no way I get into the teen and Baltimore gets to 20 degrees.

Apparent temps: wind chills.

[yoda]

LONG TERM /MONDAY THROUGH FRIDAY/...
Surface cold front will be off the Atlantic coast Monday
morning with a deep parent upper trough expected to pivot
overhead by early Tuesday. Strong cold air advection is expected
behind this front Sunday night through Monday evening on
blustery NW winds gusting up to 35 mph. Temperatures Monday and
Tuesday will be hard to get out of the 40s with wind chills in
the 20s at night and mid 30s during the day. Accumulating snow
showers are expected for areas west of the Allegheny Front. High
Froude numbers on Monday associated with the strong NW flow
indicate potential for snow showers to make it well east of the
mountains Monday afternoon, possibly dusting the ground in a few
places. Over the mountains, two to fourth tenths liquid water
equivalent amounts combined with high SLRs of 18 to 1 may yield
snow totals of 3 to 7 inches over the favored upslope areas such
as Bayard WV and western Garrett County MD. As of right now, it
still looks like an advisory level snow event with a small
chance of meeting warning criteria.

[Weather Will]

WB latest weeklies.  Cool and normal precip leading into Christmas.  Does not look like a torch leading into the holidays this year.

[Stormchaserchuck1]

7 hours ago, Terpeast said:

Would you say that the PNA pushing positive despite the +WPO/Pacific marine heat wave is what's behind some of the suppressed storm tracks that gave Louisiana and Florida and SE VA double digit snows? That's just me visualizing the patterns in my head... but I haven't really looked at the PNA data (been heads down with MJO at work lately).

+WPO is actually cooler pattern in the extreme Southeast. It's main effect is a ridge in SE Canada and around the Great Lakes/Midwest/Northeast. I think the digging trough that was +wpo/+pna related, and the fact that it happened 1 day from the coldest of the year on average (Jan 27). Surprisingly, the NAO/AO was not negative for that event.. so in the optimal scenario, it could have gone even further south! 

[frd]

36 minutes ago, Weather Will said:

WB latest weeklies.  Cool and normal precip leading into Christmas.  Does not look like a torch leading into the holidays this year.

Of course there is very little fundamental accuracy this far out however it would be nice to see a more robust signal for precipitation in our area. 

 

A lot will depend on the configuration and presence of blocking if we are to get any snowfall prior to the holidays. 

 

And years past going far back with a Nina when it has been cold in December which has happened on quite a few occasions it has normally been dry right when the cold snap ends was when the precipitation set in as you can imagine a typical occurrence cold dry warmer wetter.

[WxUSAF]

Totally my anecdotal observations, but it seems like the weeklies are ok at picking out a single “pattern change” during the forecast period, but then don’t properly show how that new pattern may evolve or change. So I buy a “good” pattern develops after thanksgiving, but I doubt it looks the same for the subsequent 4 weeks.

[CAPE]

51 minutes ago, WxUSAF said:

Totally my anecdotal observations, but it seems like the weeklies are ok at picking out a single “pattern change” during the forecast period, but then don’t properly show how that new pattern may evolve or change. So I buy a “good” pattern develops after thanksgiving, but I doubt it looks the same for the subsequent 4 weeks.

Imo the extended products are 'useful' a week to 10 days beyond day 15 of the latest ens runs. Beyond that.. crapshoot.

[Stormchaserchuck1]

We haven't had a Week 3-4 this cold since January last year. 

[Stormchaserchuck1]

15 minutes ago, CAPE said:

Imo the extended products are 'useful' a week to 10 days beyond day 15 of the latest ens runs. Beyond that.. crapshoot.

Is there a place that does the 2-6 week forecasts for GEFS and EPS for free, or do you have to pay for it? 

[Eskimo Joe]

The 18z GFS has finally started to trend toward the Euro and Canadian at bringing the PV lobe farther southwest. Maybe this increases the chances for conversational flurries on Monday, 11/10?

[Stormchaserchuck1]

18z GFS ensembles has a strong -NAO through the whole run.. we haven't seen something like that in a while.. we've had -NAO's but they've had problems sustaining. GEFS says 15 days and going, which is a good trend! It doesn't rapidly switch back to positive at the end of the run right now. 

At 84hr we have <-360dm 500mb going through PA/MD/VA. That's a big negative anomaly!