December Mid-Long Range Discussion

[usedtobe]

The superenemble mean from last night still shows a warmish pattern through the dec 17th or so. Note the ridge in the pacific forces lower heights in the west which in turn leads to a positive anomaly over the southeast. It's almost an identical pattern to the one shown on my last CWG discussion that Mitch and a few others weren't so happy about. Such a pattern would again favor lows tracking to our north leaving us in the warm sector.

The gefs 300 hr ens mean from the 06Z run has a cooler look as it pulls the positive anomaly associated with a negative nao westward enough to actually lower our heights. there even is a slightly below normal light blue area of southeaster VA and NC. That gives a little hope that a weak wave could slip south of us but the location of the ridge in the Pacific and the negative heights over the southwest suggest the low track would probably not be that favorable at least for a primary low. I'm also not yet ready to buy the western placement of the high heights over Greenland. It seems like the models have tried that a run or two before without it happening.

I still am not overly excited by the pattern. If the blocking does come west strongly into Greenland there is precident for getting out temps to or below normal (see don sutherland's post from yesterday. However, usually for long range stuff, it's wiser to hold off on making a big pattern flip to colder until there is more consensus. The CFS2 model for week 3 shows really cold air across western Canada but most of the eastern half of the u.s. being warmer than normal. It flips every couple of days.

[stormtracker]

It's only 10 days away guys.

[Bob Chill]

Wes, what are your thoughts irt a comparison with Dec 61? It's not common to have a -pna/ao/nao combo. I could only find a couple instances where it was anomalous. Dec of 96 had it as well.

I tend to agree that odds favor a warmer pattern with the lowest heights in the conus out west. And it's also not a good idea to just jump in a buy the gfs' handling of the nao yet. Especially this far out. But the 500 anom maps between this dec and dec 61 are pretty similar. Especially in the pac. Does make me wonder if a flip to cold isn't as far fetched as it may seem.

[mitchnick]

The superenemble mean from last night still shows a warmish pattern through the dec 17th or so. Note the ridge in the pacific forces lower heights in the west which in turn leads to a positive anomaly over the southeast. It's almost an identical pattern to the one shown on my last CWG discussion that Mitch and a few others weren't so happy about. Such a pattern would again favor lows tracking to our north leaving us in the warm sector.

huh...I didn't read it

[Deck Pic]

Wes, what are your thoughts irt a comparison with Dec 61? It's not common to have a -pna/ao/nao combo. I could only find a couple instances where it was anomalous. Dec of 96 had it as well.

I tend to agree that odds favor a warmer pattern with the lowest heights in the conus out west. And it's also not a good idea to just jump in a buy the gfs' handling of the nao yet. Especially this far out. But the 500 anom maps between this dec and dec 61 are pretty similar. Especially in the pac. Does make me wonder if a flip to cold isn't as far fetched as it may seem.

nice comparison and it is going to take some time.....I think there is a reasonable shot of a good last 1/3 of DEC IF we get the central/west based block which has been hinted at....The Pacific is probably going to remain somewhat hostile though Wes's post suggests it may get better...I think it is going to take til at least the last week of DEC for us to get a period of below normal heights in the mid-atlantic/southeast...

[WinterWxLuvr]

The superenemble mean from last night still shows a warmish pattern through the dec 17th or so. Note the ridge in the pacific forces lower heights in the west which in turn leads to a positive anomaly over the southeast. It's almost an identical pattern to the one shown on my last CWG discussion that Mitch and a few others weren't so happy about. Such a pattern would again favor lows tracking to our north leaving us in the warm sector.

The gefs 300 hr ens mean from the 06Z run has a cooler look as it pulls the positive anomaly associated with a negative nao westward enough to actually lower our heights. there even is a slightly below normal light blue area of southeaster VA and NC. That gives a little hope that a weak wave could slip south of us but the location of the ridge in the Pacific and the negative heights over the southwest suggest the low track would probably not be that favorable at least for a primary low. I'm also not yet ready to buy the western placement of the high heights over Greenland. It seems like the models have tried that a run or two before without it happening.

I still am not overly excited by the pattern. If the blocking does come west strongly into Greenland there is precident for getting out temps to or below normal (see don sutherland's post from yesterday. However, usually for long range stuff, it's wiser to hold off on making a big pattern flip to colder until there is more consensus. The CFS2 model for week 3 shows really cold air across western Canada but most of the eastern half of the u.s. being warmer than normal. It flips every couple of days.

Interesting Wes that 1992 and 1984 are in that list. Those were "late blooming" winters, at least down in SWVA. I also find it of note that 1970 is showing up there as I mentioned it yesterday. It's a good analog up to this point, but there's no way to know if we end up like that winter. I don't really have any stats on that one, or the other two for that matter, for this area except that Winchester had a good snow season in 1970-1971 (it was a good Dec snow month as well).

[Bob Chill]

GFS says its not sure whats going to happen after the cutter. Not that bad of a look and a 300hr threat. lol

At the very least it doesn't look torchy in the lr.

[WVclimo]

Interesting Wes that 1992 and 1984 are in that list. Those were "late blooming" winters, at least down in SWVA. I also find it of note that 1970 is showing up there as I mentioned it yesterday. It's a good analog up to this point, but there's no way to know if we end up like that winter. I don't really have any stats on that one, or the other two for that matter, for this area except that Winchester had a good snow season in 1970-1971 (it was a good Dec snow month as well).

I looked around for some good Winchester data, and couldn't find any either, prior to the late 90's.

1970-71 had 34.2" at MRB. Wasn't a very cold winter, but the 12.3" snow on New Years Eve/ Day was on the ground for most of January.

1984-85 is not a winter we want to see again. 12.5" of snow at Martinsburg, and with the exception of the severe cold snap around the time of Reagan's 2nd inauguration it was a really warm winter. 70+ degree highs the last half of December, including a 77 at MRB on the 29th. Then winter basically ended 2/15.

1992-93 was a 43.9" winter Wasn't much cold around, but when it did get cold enough it produced, with frequent snowfalls in February and March. An excellent year to be N and W.

Bob Chill's 1961-62 winter was also a good one here. 38.6" including the 18" of wind-driven snow on 3/5-6.

[nw baltimore wx]

GFS says its not sure whats going to happen after the cutter. Not that bad of a look and a 300hr threat. lol

At the very least it doesn't look torchy in the lr.

That run looks like it is trying to set us up for some Christmas shopping in the snow.

[eurojosh]

That run looks like it is trying to set us up for some Christmas shopping in the snow.

Perhaps, but I'd trade 4 inches on the 312hr GFS for 1 inch on the 24hr Euro...

[MillzPirate]

the GFS has been hinting at a coastal storm sometime in the 15th-18th range for several days now

[bjohnson102184]

Perhaps, but I'd trade 4 inches on the 312hr GFS for 1 inch on the 24hr Euro...

Crawl before you can walk........

[Bob Chill]

After taking a better look at the GFS it's still hanging on to the notion that the nao is going be a bit more favorable and the AO looks quite negative too.

I you run the 250 and 500 loops in the npac it looks kind of interesting too. Not an active STJ but the flow into the US looks pretty good. At the very least it appears the gulf is open for business if anything in the ns can dig. Maybe the dry pattern is changing?

It precarious at best to think that things are going to turn quickly in our favor but models are at least picking up on some potential important changes. Gotta get through a storm track to our west first. That's all but guaranteed. What happens after is still pretty much unknown.

[Bob Chill]

This illustrates much better than what I was trying to say:

Yea, I know it's 300 hours and I'm not expecting anything. Just pointing out the progged flow over the pac and conus. IF anything brewed along the gulf coast in this setup it would be pretty wet. Something to keep an eye on for another 6 hours before it vanishes.

[nw baltimore wx]

This illustrates much better than what I was trying to say:

Yea, I know it's 300 hours and I'm not expecting anything. Just pointing out the progged flow over the pac and conus. IF anything brewed along the gulf coast in this setup it would be pretty wet. Something to keep an eye on for another 6 hours before it vanishes.

What's it going to take to have that building ridge in the Pacific completely break down that trough?

[Bob Chill]

What's it going to take to have that building ridge in the Pacific completely break down that trough?

That will take time but it's not necessary for us to have a decent pattern. It all comes down to the placement and strength of the -nao. The GFS op and ens both show some good stuff. As long as the nao isn't too far east it really puts the squeeze on the flow pushes the higher heights out of the way after 192 hrs or so.

The op looks really good in fantasy land too. Solid -nao and the lower heights over AK bulge and start to push the ridge in the pac to the east. This map progression illustrates it pretty well but I don't really believe it yet.

This is hr 192-240-300 of 12z gfs:

[nw baltimore wx]

That will take time but it's not necessary for us to have a decent pattern. It all comes down to the placement and strength of the -nao. The GFS op and ens both show some good stuff. As long as the nao isn't too far east it really puts the squeeze on the flow pushes the higher heights out of the way after 192 hrs or so.

The op looks really good in fantasy land too. Solid -nao and the lower heights over AK bulge and start to push the ridge in the pac to the east. This map progression illustrates it pretty well but I don't really believe it yet.

This is hr 192-240-300 of 12z gfs:

If nothing else, it at least looks like there's some hope. As has been discussed by others, sometimes things play out more slowly in the real world than the models suggest, but hopefully those maps suggest that a change may be coming. Personally, I'm hoping it happens the week before and through Christmas.

[Bob Chill]

If nothing else, it at least looks like there's some hope. As has been discussed by others, sometimes things play out more slowly in the real world than the models suggest, but hopefully those maps suggest that a change may be coming. Personally, I'm hoping it happens the week before and through Christmas.

You pretty much have to think the gfs is going too hog wild. It may be onto the right idea but it's tough to buy being cold coast to coast. Especially with the ridge in the pac. Sure it can happen but the NAO needs to be an awful big bully to make it happen.

I think in reality we'll see things trend towards better blocking around GL but until the ridge in the pac makes a move we probably are on the outside looking in here in the ma. The nao could flex enough to put NE in the game but what else is new.

[WinterWxLuvr]

I looked around for some good Winchester data, and couldn't find any either, prior to the late 90's.

1970-71 had 34.2" at MRB. Wasn't a very cold winter, but the 12.3" snow on New Years Eve/ Day was on the ground for most of January.

1984-85 is not a winter we want to see again. 12.5" of snow at Martinsburg, and with the exception of the severe cold snap around the time of Reagan's 2nd inauguration it was a really warm winter. 70+ degree highs the last half of December, including a 77 at MRB on the 29th. Then winter basically ended 2/15.

1992-93 was a 43.9" winter Wasn't much cold around, but when it did get cold enough it produced, with frequent snowfalls in February and March. An excellent year to be N and W.

Bob Chill's 1961-62 winter was also a good one here. 38.6" including the 18" of wind-driven snow on 3/5-6.

I've got Winchester data back to about 1900. I don't know how reliable it is, but it is precise. It has the winters (analogs) of 1961, 1966, 1970 as good snow years. I don't have that data on this computer, but I do know that 1993 is the Superstorm year (of course).

[Bob Chill]

And the euro says don't put away your t-shirts yet. Just a bit different handling of the nao in the lr. GFS says big negative and euro says going big positive. uh oh.

I think the wrong panel loaded on raleigh's site. I just hit refresh and the -nao is there. -pna is winning though but that's fine. GFS and Euro are similar in some ways. Main diff with the euro is the trough out west is deeper and the nao is a bit further east.

[Snow_Miser]

And the euro says don't put away your t-shirts yet. Just a bit different handling of the nao in the lr. GFS says big negative and euro says going big positive. uh oh.

I think the wrong panel loaded on raleigh's site. I just hit refresh and the -nao is there. -pna is winning though but that's fine. GFS and Euro are similar in some ways. Main diff with the euro is the trough out west is deeper and the nao is a bit further east.

The 12z ECMWF is better with how it handles the NAO when compared to the 00z run. You can see some positive anomalies getting established in the crucial west based regions, whereas those positive anomalies were virtually non-existent on the 00z run. Warm for the east because of the -PNA though.

[clskinsfan]

The Pac is just ugly. But I am loving the look of that west based -NAO....We are going to need that to have any chance with the Pac the way it is.

[WinterWxLuvr]

The 12z ECMWF is better with how it handles the NAO when compared to the 00z run. You can see some positive anomalies getting established in the crucial west based regions, whereas those positive anomalies were virtually non-existent on the 00z run. Warm for the east because of the -PNA though.

Isn't that from Nov?

Now its not.

[WVclimo]

I've got Winchester data back to about 1900. I don't know how reliable it is, but it is precise. It has the winters (analogs) of 1961, 1966, 1970 as good snow years. I don't have that data on this computer, but I do know that 1993 is the Superstorm year (of course).

That's cool that you have that. I'd love to see it. I'd be interested in cross-checking some events with another local station, if you'd be amenable to sharing. The data I have from Martinsburg has some odd reports included that I have tried to compare to nearby COOP stations to get a better sense of what took place, but its always tough finding good data for specific events.

Also, the MRB data begins in 1926 when the airport started, and that excludes a lot of good stuff from the first couple of decades of the 20th century, which featured some pretty extreme weather at times.

[WinterWxLuvr]

That's cool that you have that. I'd love to see it. I'd be interested in cross-checking some events with another local station, if you'd be amenable to sharing. The data I have from Martinsburg has some odd reports included that I have tried to compare to nearby COOP stations to get a better sense of what took place, but its always tough finding good data for specific events.

Also, the MRB data begins in 1926 when the airport started, and that excludes a lot of good stuff from the first couple of decades of the 20th century, which featured some pretty extreme weather at times.

Be happy to do that once I'm home. If I forget, PM me. I don't have that site here and don't even know it by name. It's not great for all years, but is good for years pretty far back.

[usedtobe]

huh...I didn't read it

I thought you commented on it, I probably mixed you up with Leesburg or someone else. They were actually made comments in a joking manner

..Bob, I found 8 (I think) of your 18 years to have a rpna and neg AO and posted the worst outcome for the month. The others were not as bad and ranged from normal to below normal. I think the 1st half of Dec is pretty much lost. As to the 1961 analog, none of the 10 dates for the superens mean from last night were from 1961 for what that is worth. The 360 GFS ebs neab looks somewhat interesting with the low heights over New England suggesting that the west based nao may be exerting itself. That is what happened during the bulk of your neg pna, neg nao years so it's probably going to eventually happen. IThe euro has a closed 500h blocking high that is still east of where we want it at 240 hrs but it probably will retrogress somewhere down the line. The Pacific still is a problem suggesting storms would have to be weak or reform after tracking to the OH balley. Anyway that's my quick take on the subject though I really didn't look at it for very long as I've been visiting with friends from AZ all day.

[ravensrule]

I thought you commented on it, I probably mixed you up with Leesburg or someone else. They were actually made comments in a joking manner

..Bob, I found 8 (I think) of your 18 years to have a rpna and neg AO and posted the worst outcome for the month. The others were not as bad and ranged from normal to below normal. I think the 1st half of Dec is pretty much lost. As to the 1961 analog, none of the 10 dates for the superens mean from last night were from 1961 for what that is worth. The 360 GFS ebs neab looks somewhat interesting with the low heights over New England suggesting that the west based nao may be exerting itself. That is what happened during the bulk of your neg pna, neg nao years so it's probably going to eventually happen. IThe euro has a closed 500h blocking high that is still east of where we want it at 240 hrs but it probably will retrogress somewhere down the line. The Pacific still is a problem suggesting storms would have to be weak or reform after tracking to the OH balley. Anyway that's my quick take on the subject though I really didn't look at it for very long as I've been visiting with friends from AZ all day.

I cannot believe you did not spend all day on this, and have not been busy making videos all day. You should be ashamed of yourself.

[Bob Chill]

Appreciate the insight as always Wes. I'm not even paying attention to the first half of the month. That fate appears to be sealed. Once the relatively strong cutter makes it's pass things should be a bit more clear one way or another. At the very least it seems plausible for things to improve as we get into the last 10 days of the month. And that's totally fine too.

I graphed the 1961 Nov-Dec daily pna index and there was a pronounced flip positive at the end of the month. There are some similarities with 61 and 2012 with the Nov-Dec pna. I can't believe how long the PNA has been negative. Quite a stretch of months with a - reading (going on 7 now) and now we have quite a stretch of consecutive days. All bad things must come to an end right? lol

[mitchnick]

I thought you commented on it, I probably mixed you up with Leesburg or someone else. They were actually made comments in a joking manner

..Bob, I found 8 (I think) of your 18 years to have a rpna and neg AO and posted the worst outcome for the month. The others were not as bad and ranged from normal to below normal. I think the 1st half of Dec is pretty much lost. As to the 1961 analog, none of the 10 dates for the superens mean from last night were from 1961 for what that is worth. The 360 GFS ebs neab looks somewhat interesting with the low heights over New England suggesting that the west based nao may be exerting itself. That is what happened during the bulk of your neg pna, neg nao years so it's probably going to eventually happen. IThe euro has a closed 500h blocking high that is still east of where we want it at 240 hrs but it probably will retrogress somewhere down the line. The Pacific still is a problem suggesting storms would have to be weak or reform after tracking to the OH balley. Anyway that's my quick take on the subject though I really didn't look at it for very long as I've been visiting with friends from AZ all day.

don't get me wrong; I didn't read it because the subtext told exactly what it was going to say

[mitchnick]

Appreciate the insight as always Wes. I'm not even paying attention to the first half of the month. That fate appears to be sealed. Once the relatively strong cutter makes it's pass things should be a bit more clear one way or another. At the very least it seems plausible for things to improve as we get into the last 10 days of the month. And that's totally fine too.

I graphed the 1961 Nov-Dec daily pna index and there was a pronounced flip positive at the end of the month. There are some similarities with 61 and 2012 with the Nov-Dec pna. I can't believe how long the PNA has been negative. Quite a stretch of months with a - reading (going on 7 now) and now we have quite a stretch of consecutive days. All bad things must come to an end right? lol

odd though Bob

11/61 gave BWI 3.2" and this year nothing

otoh, the storm after Sandy was close to something here for sure, so maybe the warmer regime killed us idk....you can see I'm stretching here so save me! lol