Phil

I actually tend to agree with Jim on this one (snowwizzard). Our most epic late December/January's had shitty Novembers. 1915, 1949, 1968, 1971, 1988, 1990, 2003, 2008... yeah some of these years weren't incredible, but find a year that featured an arctic blast and snow at SEA in Nov that also featured a top tier blast in the Dec 20-Jan 31 period...

 

Jim is hoping for the big blast in late December through January. If we get a full fledged blast in November, it more than likely means we won't have a top tier December or January... it's just how s**t works here. The atmosphere doesn't like multiple full fledged artic blasts in the PNW in one winter. Anyone can say oh what about November 2006, or 2010. There are exceptions to every rule...

 

I'm also a little confused on the whole PNA discussion between Phil and Jim. I think we're talking apples to oranges. Old PNA and new PNA seem scaled totally different. I don't even think the new PNA is very indicative of PNW troughing. The old PNA basically mirrored the pattern in the PNW. If there was a GOA ridge and PNW trough the PNA was negative, vice versa. Jim's outlook on this is a bit more simplified as opposed to Phils.

 

Jim remember diving into the PNA/PDO and the NP index for hours on end back in the mid 2000s? Miss those days bud.

The two PNA calculations are fairly similar overall..both are positive for this month. The problem is there really hasn't been much GOA ridging this month. There was a period of EPO blocking/anticyclonic breaking during the first week of the month, but nothing that resembled a -PNA.

Sure, a -EPO usually does lead to western troughing, but that's not the same thing as a -PNA. I want to see a -PNA develop in November, because there are no analogs with top-tier January blasts that featured +PNAs in both October and November:

It is interesting to note the "old formula" PNA does show we have had some negative PNA episodes this month. I have never understood the finer points of the new formula, but sometimes it doesn't show negative PNA when we have a GOA ridge / Western trough. I would also like to make the point it might be fine to have negative PNA in November, but I want to avoid significant cold weather during the month. Hope that clears everything up.

 

ftp://ftp.cdc.noaa.gov/Public/gbates/reforecast2/teleconn/pna.png

Improved domainal consistency and overlap in the new version.

Semantics aside, October will clearly finish as a coherent +PNA month. Not much GOA blocking, but plenty of polar blocking, which is a good thing in the long run.

However, noting this fact, a warm/+PNA November is something that we'd want to avoid at all costs after a +PNA October. Analogs get ugly fast when you start stringing +PNA months together like that during the autumn, regardless of ENSO/QBO, as it's often reflective of a background boundary state of some sort.

The 00z GFS is depicting the craziest +WPO/+PNA/-AO pattern I've ever seen. Holy smokes.

I'd like the 1983/84 analog a lot more if it didn't feature a supermassive black hole at the North Pole. Otherwise, it's a pretty good one IMO.

FWIW, I think there's a good chance we see the lowest October AO in recorded history this year. Definitely notable/important in regards to forward progression/extrapolative analoging.

Perfect fall day and a great way to abruptly rid the world of any reminders of summer.

 

Late November looks interesting.

Today @ Bald Knob, WV. 'Tis almost that time of year.

https://m.facebook.com/story.php?story_fbid=1166074236813494&id=577901605630763&__tn__=%2As

I do not think his "rooting" will make a big difference what the outcome is... Just saying Let him root ... we get what we get and it may be s**t or a big hit... OOOOoooo poetic.

Lol, wasn't trying to suggest he's god in disguise. Just trying to understand his line of thinking here, that's all.

I don't buy this November blast = crap January thing at all. I guess it depends on what you consider "major", but these are the biggest ones on record:

 

1896 (late January arctic intrusion, ridiculously cold March)

1900 (early January cold and snow)

1911 (late December/early January cold and snow

1955 (great winter, including cold in late January/early Feb)

1985 (long fake cold spell in December, torch January)

2006 (cold/snow in January)

2010 (cold spell in late December/early January that was close to awesomeness, late Feb blast)

 

Seems like every winter in our recorded history that had a major cold wave in November had something else later on, and all but one of them had something in January - the only exception was 85-86, but the extended November cold/snow and the December cold more than makes up for that. I guess we've never had a truly epic 1916/1950 type January after a November cold wave, but those kind of Januaries are very rare in the first place. I see no reason why you wouldn't want to see a major blast in November.

Exactly. Plus +PNA Novembers during -ENSO tend to precede winters with weaker SE-ridges by frequency, not to mention more +PNA and/or +EPO.

Especially after a +PNA October..the -ENSO years with back to back +PNAs in Oct/Nov are (generally) sucky in the PNW.

We want to suppress the subtropical high south to allow cooler/ wetter weather for the Southwest during winter. What do you see in terms of rainfall for California later this week and into November, Phil?

 

I think California will actually cash in on some storminess during early and/or mid November, as another +WPO surge in concurrence with a completion of a strong EAMT cycle weakens/dislodges the standing convective wave @ 120E, weaking the Walker Cell and leading to another Niño-esque pattern for at least the first 10 days of November.

Didn't you see the map I made? The Novembers were obviously GOA trough, Western ridge, Eastern trough. Sounds like +PNA to me. Either that or I'm missing something.

The point was, years that were +PNA in October, then flipped around to -PNA in November, were much better winters in the PNW than years that were +PNA in both October and November. No analog years w/ +PNAs in both October and November featured Arctic blasts during the following Januaries.

This October will finish with a fairly strong +PNA. Not a single day with a -PNA, actually. Statistically, you'd definitely want a flip into a -PNA during November, otherwise..well, we can cross that bridge if/when we come to it.

I really hope we skip November. I suppose we could get away with a borderline snow. The thing we want to avoid is extreme blocking with a major cold wave in November.

I still don't understand your line of thinking here. There aren't any analog years that featured a +PNA in both October and November, followed by an Arctic blast in January. None. Zero.

Why would you root for something that'd statistically eliminate your chance for a midwinter blast?

Is this just a hunch? Not saying I have the answers, but the past is often prologue in cases like this, IMO.

My original feeling was that December and February would be our 2 best months. Could be another bookend winter in the works.

Many of the analogs are hinting at February, yeah. Personally I think the strongest blocking will set up during January, but exactly where is another story. Hard for me to tell.

A poleward migration of the subtropical high (if it's over the NE Pacific) would make it easier to get Arctic air into the NW. Placement of the high is pretty crucial.

It's not the subtropical high (itself) that breaks poleward during Arctic events, though.

Now for how those winters (Jan & Feb) turned out. A 180 degree reversal.

Want to guess how many of those were +PNA in both October and November?

Answer is two, and neither are very reflective of the pattern ongoing since late August. In -ENSO years where October featured a +PNA, those that flipped -PNA in November were much better winters in the PNW. It's not really debatable IMO.

That wasn't the issue at all from 2006-14. Was the Pacific Hadley Cell weaker in that period (which also happened to be dominated by -PDO/-ENSO)?

Well, I never said it'd preclude Arctic intrusion. There were several factors supporting Arctic intrusion during that time period, and the results would have been more impressive under an antecedent equatorward Hadley Cell regime.

All else ignored, Niña/-PDO favors a weaker but broader Pacific Hadley Cell, so there's more extratropical variability there in general. El Niño favors a stronger/tighter Pacific Hadley Cell overall.

Warm and wet. Feels like it might flip the second half of November.

That's been my thinking too..about a week before thanksgiving?

12z EPS is still bullish on the +PNA/+WPO through d15, FWIW.

http://i724.photobucket.com/albums/ww243/phillywillie/Mobile%20Uploads/DB7091E0-3881-40BB-AE1F-8482AAC44F4B_zps3m3iwsju.png

What -ENSO years have seen that? I imagine it's a fairly short list.

Eliminating stronger Niñas, the most recent years are 1959/60, 1980/81, 1983/84, and 2008/09, though 1983/84 and 2008/09 aren't very similar pattern wise.

Stronger Niñas that accomplished this include 1974/75, 1988/89, 1998/99, 1999/00, 2000/01, and 2007/08. Mostly crappy winters except for 1988/89.

Is that why Spokane had their snowiest two year period on record from 2007-09?

Is Spokane a borderline snow climate like SEA/PDX et al?

A few things here:

1) What timescale are you looking at? The Hadley Cells are quite unstable, and vary significantly on month-to-month scales, in both latitude and intensity, sometimes by 50-70% of the entire trend since the 1970s, though usually not quite to that extent.

2) The broadening Hadley Cells are reflected by a poleward migration of the subtropical highs, northern jet, and the horse latitude desert zones, as well as a weakened/wider ITCZ/equatorial convective integral. So, overall, this makes it more difficult for Arctic air to enter the PNW, and while this might not matter for less borderline locations like Spokane, it'll make a difference in the western lowlands.

It should also be noted that the Atlantic Hadley Cell hasn't reorganized in the same manner as the NPAC cell, and is subject to more significant absolute intraseasonal variability regardless, so these effects have been less noticeable in the Eastern US/Europe over recent decades (though other significant expressive shifts have occurred there).

We did have that major block that would have caused a major Arctic blast (if it had been winter) earlier in the month though. You seem to freaking out a bit.

I'm still optimistic for you this winter. Always have been.

I'll be less optimistic if November runs another +PNA, though.

Note there hasn't been a single -PNA day in October so far..

After a +PNA October, we definitely don't want to see November follow with another +PNA. Very ugly stats on -ENSO years w/ back to back +PNAs in Oct/Nov, with a few exceptions.

http://www.cpc.ncep.noaa.gov/products/precip/CWlink/pna/pna.sprd2.gif

We're fine. November is getting close and we want positive PNA in November after the long reign of GOA ridging. Perfect progression. I would have liked to have gotten one more good negative PNA spike before the end of October, but it's not a huge deal.

That's not supported by the data I'm looking at. The -ENSOs with -PNAs in November generally featured stronger -PNAs in DJF, and visa versa.

Also, October is going to finish with a clear +PNA average, so if both October and November finish with a +PNA, then statistically speaking, the forward progression becomes more problematic.

Agreed. The variation in Hadley cells is not the primary driver of local snowfall trends, IMO.

I strongly, strongly, strongly disagree.

Another thing we need to remember is the Hadley cells were also expanded in the latter part of the 19th century. It worked well for us then. I think it all comes down to overall context (the overall setting these things are couched in).

They were broad, true, but they were also weak. Essentially an inverted Hadley/Walker intensity ratio vs today, relatively speaking.

Today they're strong and broad/poleward.

Love the storm app by wunderground..very reflective wind speed maps. Can see the zone of higher winds locally, typical of downslope events.

http://i724.photobucket.com/albums/ww243/phillywillie/Mobile%20Uploads/2DCE84E7-E125-4360-A2E6-65D357A198B0_zpswgwx2ou8.png

Got my personal station up and running on the app as well. Has both real and interpolated gust values based on the timing between transmissions, I assume.

http://i724.photobucket.com/albums/ww243/phillywillie/Mobile%20Uploads/A4D60463-F2BD-4793-B1EF-5CFC92B32FD9_zpspaxtvsic.png

I personally believe LWX is (once again) underestimating winds east of the Blue Ridge.

 

Current forecast is for 30-35mph gusts, which makes no sense to me. I'd put money down that DCA, IAD, and BWI all observe gusts between 40-50mph by noon Saturday.

With winds gusting between 40-50mph area wide today, LWX has finally caved and issued a last-minute wind advisory. I love LWX to death, but I think this one was obvious given W/NW wind climo is fairly straightforward here, IMO. Downslope days almost always overperform modeling south of the Mason-Dixon line when insolation is ample, especially on the bookends of the cold season.

WIND ADVISORY UNTIL 5PM EDT SAT WIND ADVISORY IN EFFECT UNTIL 5 PM EDT THIS AFTERNOON

THE NATIONAL WEATHER SERVICE IN BALTIMORE MD/WASHINGTON HAS ISSUED A WIND ADVISORY WHICH IS IN EFFECT UNTIL 5 PM EDT THIS AFTERNOON.

* TIMING ONGOING. STRONG WINDS WILL CONTINUE THROUGH THE AFTERNOON BEFORE DIMINISHING THIS EVENING.

* WINDS NORTHWEST WINDS WITH GUSTS OF 45 TO 50 MPH POSSIBLE.

* IMPACTS SCATTERED TREE AND POWER LINE DAMAGE. DIFFICULTY DRIVING HIGH PROFILE VEHICLES.

PRECAUTIONARY/PREPAREDNESS ACTIONS A WIND ADVISORY MEANS THAT WINDS OF 45 TO 55 MPH ARE EXPECTED. WINDS WILL BE STRONG ENOUGH TO MAKE DRIVING DIFFICULT ESPECIALLY FOR HIGH PROFILE VEHICLES. DRIVE CAUTIOUSLY.