December and a Hint of January Pattern Discussion

[Bob Chill]

Our big mid month warmup looks to be mid 50's friday and low 60's saturday. That is all. 

[usedtobe]

GFS op showing a second wave on the boundary after the front clears. Ens semi-agree. SS alive and well. 22nd-24th definitely a period of interest if nothing else.

The GEFS members are all over the place on the placement of the trough at 240 with implications that the next low could still go to our north even though the euro has the front through really quickly.  A few members really pulls the trough back in the west.  Makes for an interesting pattern but a messy one.  Not the kind I like to forecast. 

[usedtobe]

Our big mid month warmup looks to be mid 50's friday and low 60's saturday. That is all. 

I think there were be two days in the 60s.  one will have it's high in the morning sort of like we had with the last warm shot. 

[Bob Chill]

The GEFS members are all over the place on the placement of the trough at 240 with implications that the next low could still go to our north even though the euro has the front through really quickly.  A few members really pulls the trough back in the west.  Makes for an interesting pattern but a messy one.  Not the kind I like to forecast. 

 

Yea, it's way way too far out there to worry about specifics. Once the frontal passage and overall boundary placement is resolved with some accuracy we can probably start to speculate a but more. Instead of period of interest I should have said the earliest chance for the cities to get accum snow.

 

This next cold shot looks pretty impressive for the conus. Our mess may not be as messy if things line up ok. 

[Ji]

have you seen the spectacular Jan flip on the CFsv2?

[Cold Rain]

have you seen the spectacular Jan flip on the CFsv2?

That took, what, about 3 days to completely reverse?

[mitchnick]

have you seen the spectacular Jan flip on the CFsv2?

just as important as temps

[Bob Chill]

Not mad at the + precip anoms in NW mexico into texas...that can only mean one thing...

[Ian]

GFS op showing a second wave on the boundary after the front clears. Ens semi-agree. SS alive and well. 22nd-24th definitely a period of interest if nothing else.

DT was hyperventalating abouTWEUFT thaGT on FDBBOKO last NIGHTSD!!! 

[ravensrule]

DT was hyperventalating thaGT on FDBBOKO last NIGHTSD!!!

Farsi would have been easier to understand.

[HM]

How did DC, BWI and really the whole area do, snowfall-wise, in the 1961 and 1990 events?

 

The dates were 12/27-28 for 1990 and 12/23-24 for 1961. In PHL, the snow totals were 6.4" and 5.9" respectively. Interestingly, both periods are beginning to show up now on long-range ensembles, post-EPO blast, as possible times moisture surges north along frontal boundary.

[usedtobe]

Today's CPC superensemble mean is the most bullish this year for the potential for a storm in it's 5 day window.  Centered on what would be the equivalent of dec 23.  Of the 10 analogs dates, only 8 years were represented as both 1951 and 1990 shows up twice with different dates.  Of the 9 independent years there years with  storms that produced more than an inch of snow at DCA. 

 

1967 which had 2 the biggest being 4.7"

1990  which had a 3 incher

1968 with a 1.2 incher

1951 2 storms, one for each of the analogs.  The biggest was 3.4"

1990 a three inch storm. 

 

It's not a pattern to get a huge storm but is one that can get a 1-5 inch storm.  It's about as good as you'll get with no blocking over Greenland or Baffin Bay. 

 

 

[usedtobe]

How did DC, BWI and really the whole area do, snowfall-wise, in the 1961 and 1990 events?

 

The dates were 12/27-28 for 1990 and 12/23-24 for 1961. In PHL, the snow totals were 6.4" and 5.9" respectively. Interestingly, both periods are beginning to show up now on long-range ensembles, post-EPO blast, as possible times moisture surges north along frontal boundary.

Both were 3 inch and change events. 

[Bob Chill]

Both were 3 inch and change events. 

 

yep, and all mixed up with drizzle and light rain either first or last. Nice pull out of cpc. White Christmas odds increasing? Article tomorrow?? lol

[gymengineer]

Today's CPC superensemble mean is the most bullish this year for the potential for a storm in it's 5 day window.  Centered on what would be the equivalent of dec 23.  Of the 10 analogs dates, only 8 years were represented as both 1951 and 1990 shows up twice with different dates.  Of the 9 independent years there years with  storms that produced more than an inch of snow at DCA. 

 

1967 which had 2 the biggest being 4.7"

1990  which had a 3 incher

1968 with a 1.2 incher

1951 2 storms, one for each of the analogs.  The biggest was 3.4"

1990 a three inch storm. 

 

It's not a pattern to get a huge storm but is one that can get a 1-5 inch storm.  It's about as good as you'll get with no blocking over Greenland or Baffin Bay. 

 

 

And I think one more year, Wes. Two days after 1/6/99, DCA had 2.2". That was the snow to freezing rain storm where the cold air hung on longer than forecast and portended the historic ice storm the following week.

[gymengineer]

yep, and all mixed up with drizzle and light rain either first or last. Nice pull out of cpc. White Christmas odds increasing? Article tomorrow?? lol

And 1990 was a decent ice storm after the snow in the suburbs. 

[HM]

Both were 3 inch and change events. 

 

 

yep, and all mixed up with drizzle and light rain either first or last. Nice pull out of cpc. White Christmas odds increasing? Article tomorrow?? lol

 

Thanks guys and good post Wes. Looks like a heightened potential here near xmas.

[WxUSAF]

I love it when Wes talks dirty. 

[winter_warlock]

Yeah, there's a definite signal there.  Wonder if the Euro will have it

hmm idk bud I think euro only goes out to 240... but im probably wrong lol

[WinterWxLuvr]

Our big mid month warmup looks to be mid 50's friday and low 60's saturday. That is all.

Yes, any prolonged warmup is in serious danger as is any chance for a warm December. A day or three in the 60's will taint a monthly average. I don't care what the average is, the fact is that Winchester has a shot at 10 straight under 40 if we can survive tomorrow, and probably more than 10 with complete snow cover before the 18th of December. The temp run would also be 17 of the last 23 under 40. Both stats are impressive. I know it hasn't been quite as cold near the cities and not anywhere near as snowy, but it's been cold. Anybody using an avg Dec temp to describe this month about next Wed is simply going to be talking out the side of their mouth. If forecasts verify, we are going to have had a cold December.

[stormtracker]

the euro goes out to 296?

 

 

hmm idk bud I think euro only goes out to 240... but im probably wrong lol

 

Cool, because Bob referenced the period beginning on the 22nd....which is 240 hours from now.

[Heisy]

Feels like the pattern is just going to reset & repeat itself, looking at both LR EURO/GFS a lot of energy is going to dive into the west just like what happened few weeks ago, it'll bleed east eventually, and we'll still have no block. Looks like an almost identical pattern. 

[TowsonWeather]

6Z GFS says White Christmas!

 

Lock it in. ;-)

[Cold Rain]

Feels like the pattern is just going to reset & repeat itself, looking at both LR EURO/GFS a lot of energy is going to dive into the west just like what happened few weeks ago, it'll bleed east eventually, and we'll still have no block. Looks like an almost identical pattern.

The LR models are relentless in not showing any blocking. Every now and then, they show a little bit of a PNA ridge and a decent trough in the east, but very soon, the progs revert back to the scenario you described above, which makes sense, given the current state of the atmosphere. But it's really striking how usually, out in fantasy land, you'll see plenty of ridging or blocking in the NAO domain, but this season so far, that isn't really even showing up at all. I guess it really speaks to how stable the +AO/+NAO is.

[Bob Chill]

Cool, because Bob referenced the period beginning on the 22nd....which is 240 hours from now.

I knew exactly what you are saying. At this range all we can really look at is trends with trough axis and timing of frontal passage.

I glanced through all the ensembles this morning. The euro is a bit slower clearing the front but that's inconsequential at this point. Everything is pointing towards getting it through before xmas eve. At the very least, odds seem pretty fair to have a cool/cold Christmas. That's important to me personally regardless of snow.

The signs are becoming more clear that the goa ridging is going to connect with ridging in the west coast. This is not a repeat of the last pattern. It's actually a more promising sign for a more substantial event. STJ remains active and it's a pretty good split flow look if everything verifies even close to what is being shown. The kind of setup that can phase something.

The placement of the boundary and how it evolves is less clear. We want don't want it to clear too far off the coast (not likely) but we also don't want it to set up too far west and wobble back and forth over us. That could happen so I don't doubt that kind of outcome. Still isn't a dagger. Just more precarious.

GFS ensembles show a good chance at moisture continuing to pulse along the boundary after it clears. Several events if you look verbatim but that's not worth worrying about. My wag is we are in the crosshairs for moisture but airmasses will be marginal again. But below normal even modestly in late december is plenty enough for some frozen. I'm feeling better than 50% odds at this time that we have an event or 2 that includes frozen during christmas week. That's about as much as you can speculate.

The split flow look has be more intrigued. With the ridging in the west, we don't need a block nearly as bad for a solid event. I'll be watching closely.

This doesn't look like a pattern repeat to me. It's not a record breaking cold dump into the pac nw that bleeds. The invasion is centered more over the rockies. as things progress eastward the ridging in the west centers re-enforcing shots into the middle of the country and our way relatively quickly. Overall, the pattern remains ripe for some form of wintry weather from Christmas - New Years.

Best december since 09! lol

[WinterWxLuvr]

I knew exactly what you are saying. At this range all we can really look at is trends with trough axis and timing of frontal passage.

I glanced through all the ensembles this morning. The euro is a bit slower clearing the front but that's inconsequential at this point. Everything is pointing towards getting it through before xmas eve. At the very least, odds seem pretty fair to have a cool/cold Christmas. That's important to me personally regardless of snow.

The signs are becoming more clear that the goa ridging is going to connect with ridging in the west coast. This is not a repeat of the last pattern. It's actually a more promising sign for a more substantial event. STJ remains active and it's a pretty good split flow look if everything verifies even close to what is being shown. The kind of setup that can phase something.

The placement of the boundary and how it evolves is less clear. We want don't want it to clear too far off the coast (not likely) but we also don't want it to set up too far west and wobble back and forth over us. That could happen so I don't doubt that kind of outcome. Still isn't a dagger. Just more precarious.

GFS ensembles show a good chance at moisture continuing to pulse along the boundary after it clears. Several events if you look verbatim but that's not worth worrying about. My wag is we are in the crosshairs for moisture but airmasses will be marginal again. But below normal even modestly in late december is plenty enough for some frozen. I'm feeling better than 50% odds at this time that we have an event or 2 that includes frozen during christmas week. That's about as much as you can speculate.

The split flow look has be more intrigued. With the ridging in the west, we don't need a block nearly as bad for a solid event. I'll be watching closely.

This doesn't look like a pattern repeat to me. It's not a record breaking cold dump into the pac nw that bleeds. The invasion is centered more over the rockies. as things progress eastward the ridging in the west centers re-enforcing shots into the middle of the country and our way relatively quickly. Overall, the pattern remains ripe for some form of wintry weather from Christmas - New Years.

Best december since 09! lol

Funny you mentioned 09.  As of today, I think it exceeds December 09, even in DC.  Correct me if I'm wrong.  Of course, we need some big events from now to New Years to stay ahead of it.

[Scarlet Pimpernel]

I knew exactly what you are saying. At this range all we can really look at is trends with trough axis and timing of frontal passage.

I glanced through all the ensembles this morning. The euro is a bit slower clearing the front but that's inconsequential at this point. Everything is pointing towards getting it through before xmas eve. At the very least, odds seem pretty fair to have a cool/cold Christmas. That's important to me personally regardless of snow.

The signs are becoming more clear that the goa ridging is going to connect with ridging in the west coast. This is not a repeat of the last pattern. It's actually a more promising sign for a more substantial event. STJ remains active and it's a pretty good split flow look if everything verifies even close to what is being shown. The kind of setup that can phase something.

The placement of the boundary and how it evolves is less clear. We want don't want it to clear too far off the coast (not likely) but we also don't want it to set up too far west and wobble back and forth over us. That could happen so I don't doubt that kind of outcome. Still isn't a dagger. Just more precarious.

GFS ensembles show a good chance at moisture continuing to pulse along the boundary after it clears. Several events if you look verbatim but that's not worth worrying about. My wag is we are in the crosshairs for moisture but airmasses will be marginal again. But below normal even modestly in late december is plenty enough for some frozen. I'm feeling better than 50% odds at this time that we have an event or 2 that includes frozen during christmas week. That's about as much as you can speculate.

The split flow look has be more intrigued. With the ridging in the west, we don't need a block nearly as bad for a solid event. I'll be watching closely.

This doesn't look like a pattern repeat to me. It's not a record breaking cold dump into the pac nw that bleeds. The invasion is centered more over the rockies. as things progress eastward the ridging in the west centers re-enforcing shots into the middle of the country and our way relatively quickly. Overall, the pattern remains ripe for some form of wintry weather from Christmas - New Years.

Best december since 09! lol

 

Interesting ideas, I've been kind of thinking the same thing and looking at the period from near Christmas to the end of the month.  Haven't looked a whole lot at the ensembles yet, but it's good to hear they're in line as well.  The deterministic GFS sure has been hinting at some very cold air pushing into the central and eastern US, and a good +PNA setting up, despite a relative lack of -NAO blocking.  It seems to have been hitting on the Dec. 25-28 time period for some kind of good storm, though it's not worth looking at specific details at this point.  Key is some kind of signal is there right now.  All in all, could be fun times ahead.

[yoda]

12z GFS blasts in some frigid air behind a CF around the 23rd... i think the loss of resolution after 192 "moderates" the blast some... otherwise it doesn't look like much goes on

[mattie g]

Funny you mentioned 09.  As of today, I think it exceeds December 09, even in DC.  Correct me if I'm wrong.  Of course, we need some big events from now to New Years to stay ahead of it.

 

I had close to 5" on 5 Dec 09, though DC proper had quite a bit less, I believe.  I've had a hair over 3" this year.

[MN Transplant]

I had close to 5" on 5 Dec 09, though DC proper had quite a bit less, I believe.  I've had a hair over 3" this year.

 

I had 3".  DCA was under an inch.