Warmest September on record

[BLI snowman]

SEA is cruising to its warmest September on record. 64.9 was their mean as of today, with the monthly record only at 64.35 (1974).

 

Looks like PDX will also cap off its warmest September on record by a hair. 67.9 was their mean going into today and 67.6 is the record (1994). 

 

While the 30 year departures  weren't completely huge (+3.5 and +3.3 respectively), that's good enough to get the job done this time of year.

[Jesse]

PDX will tie 1994 assuming they see a high of about 65 today.

 

Balmy month though. They come so easily these days. Looks like October could be a repeat!

[TT-SEA]

Nice month. 

 

Also much wetter than normal at SEA.

 

And for the record... yes we were due for more warmth after the warmth of July and August.

[Jesse]

Justin, I'm assuming this is now the warmest JAS on record for PDX as well?

[Deweydog]

Sexy.

[Dan the Weatherman]

As long as we continue to have the dominance of what has recently become known as the Ridiculously Resilient Ridge (RRR or Triple R) in the northeastern Pacific, the Pacific NW and CA are going to remain warmer than normal until there is a large scale change in this pattern. I am hoping that change comes sometime this fall so that the entire west coast doesn't get stuck in a terrible drought situation like what has happened in CA over the last two years.

[TT-SEA]

As long as we continue to have the dominance of what has recently become known as the Ridiculously Resilient Ridge (RRR or Triple R) in the northeastern Pacific, the Pacific NW and CA are going to remain warmer than normal until there is a large scale change in this pattern. I am hoping that change comes sometime this fall so that the entire west coast doesn't get stuck in a terrible drought situation like what has happened in CA over the last two years.

 

Don't bother lumping WA in with SoCal.    Its a hollow argument.

 

Seattle is running 10 inches above normal for rainfall this year... and Portland is 3 inches above normal.     And it will no doubt rain a great deal up here in the next 6 months regardless of the pattern... just how it works.

 

You guys are in a different world down there... not seeing rain for years.  

[TT-SEA]

Point of reference (over the long term) here is the total precip departure for the last 3 years.     You can see its been very wet up here overall and particularly in the Cascades which is the source of our water supply.   Those dry areas in the eastern part of WA and OR still benefit from the very wet period in the Cascades as compared to normal.

 

http://s22.postimg.org/mvc6t2gxt/anomimage.gif

[TT-SEA]

PDX will tie 1994 assuming they see a high of about 65 today.

 

Balmy month though. They come so easily these days. Looks like October could be a repeat!

 

PDX was warmer than 65... always a cold bias.      

 

Mark posted on the record being set:

 

http://fox12weather.wordpress.com/2014/09/30/warmest-september-on-record-in-portland/

[Jesse]

67/53 at PDX today brings the monthly average to 67.6 - exactly tied with 1994.

[BLI snowman]

Justin, I'm assuming this is now the warmest JAS on record for PDX as well?

 

 

Yeah, by a decent amount.

[BLI snowman]

We're having a very warm year, the only thing keeping this year from being fully historic is the very cold February. That was the last cool month for the region.

[Jesse]

We're having a very warm year, the only thing keeping this year from being fully historic is the very cold February. That was the last cool month for the region.

 

I was thinking the same thing earlier today. If February hadn't been so cold we would be surpassing 1992 right about now.

 

We'll see if we can pull off a below average November or December this year, but the weather feels like it's determined to torch for a while longer.

[BLI snowman]

I was thinking the same thing earlier today. If February hadn't been so cold we would be surpassing 1992 right about now.

 

We'll see if we can pull off a below average November or December this year, but the weather feels like it's determined to torch for a while longer.

 

 

On the bright side, the torchiest years (1934, 1958, 1992) generally have something decent in the following winter. This year's not quite on that level yet though.

[Jesse]

On the bright side, the torchiest years (1934, 1958, 1992) generally have something decent in the following winter. This year's not quite on that level yet though.

It might be if the 00z GFS verifies.

 

596dm heights in mid-October?

[Dan the Weatherman]

Don't bother lumping WA in with SoCal.    Its a hollow argument.

 

Seattle is running 10 inches above normal for rainfall this year... and Portland is 3 inches above normal.     And it will no doubt rain a great deal up here in the next 6 months regardless of the pattern... just how it works.

 

You guys are in a different world down there... not seeing rain for years.  

I am looking at this past year, not the last three lumped together. It has been warmer than normal and drier than normal for much of the west coast since last winter with the exception of NW Washington, and yes that includes Seattle and North Bend. Your area has been the exception to the rule.

[TT-SEA]

I am looking at this past year, not the last three lumped together. It has been warmer than normal and drier than normal for much of the west coast since last winter with the exception of NW Washington, and yes that includes Seattle and North Bend. Your area has been the exception to the rule.

 

 

Yes... ironically the wettest Feb-Aug in Seattle history.    

 

Nonetheless... the whole region was thoroughly soaked last week and even when the PNW is 'dry' in the winter months (Oct-Apr) its still quite wet here.

 

Have you been up here?   You might look at a precip departure map and see brown up here and imagine things looking like SoCal.    We could be extremely dry in the winter and its still sopping wet by your standards.   

[BLI snowman]

It might be if the 00z GFS verifies.

 

596dm heights in mid-October?

 

Well, for a year that's been so warm it also really hasn't had much of any historic heat. So there's that.

[Jesse]

Well, for a year that's been so warm it also really hasn't had much of any historic heat. So there's that.

I could be wrong but I thought 1934, 1958 and 1992 didn't really have any historic heat waves either. Just sustained warmth for long stretches of the year.

 

Patterns that produce historic heat tend to have more ups and downs associated with them.

[Jesse]

Btw, from what I can tell, SEA had an average of 65.7 in September 1967, meaning this year wasn't the record.

[BLI snowman]

I could be wrong but I thought 1934, 1958 and 1992 didn't really have any historic heat waves either. Just sustained warmth for long stretches of the year.

 

Patterns that produce historic heat tend to have more ups and downs associated with them.

 

1958 might be comparable, although the July 1958 event was pretty intense. 1934 (March, April, October) and 1992 (February, May, June) each had some fairly remarkable airmasses.

[BLI snowman]

Btw, from what I can tell, SEA had an average of 65.7 in September 1967, meaning this year wasn't the record.

 

Good call, I actually overlooked that one yesterday as I hurried through the data. 1967 was the warmest September on record statewide, and it should stay that way.

 

Also worth noting that though PDX may have inched their way to a monthly record, 90% of it was due to the warm lows. September 2014 wasn't even top 5 in Portland for average highs. I think that indicates that PDX's record results were an anomaly and largely UHI related.

[TT-SEA]

Good call, I actually overlooked that one yesterday as I hurried through the data. 1967 was the warmest September on record statewide, and it should stay that way.

 

Also worth noting that though PDX may have inched their way to a monthly record, 90% of it was due to the warm lows. September 2014 wasn't even top 5 in Portland for average highs. I think that indicates that PDX's record results were an anomaly and largely UHI related.

 

Don't think it was anomaly... although if it was UHI then it would be something more permanent.    Here is Cliff's take:

 

http://cliffmass.blogspot.com/2014/09/minimum-temperature-heat-wave.html

[Deweydog]

Good call, I actually overlooked that one yesterday as I hurried through the data. 1967 was the warmest September on record statewide, and it should stay that way.

 

Also worth noting that though PDX may have inched their way to a monthly record, 90% of it was due to the warm lows. September 2014 wasn't even top 5 in Portland for average highs. I think that indicates that PDX's record results were an anomaly and largely UHI related.

From a 500mb perspective, this month was certainly nothing special. The entire summer for that matter...

[Jesse]

From a 500mb perspective, this month was certainly nothing special. The entire summer for that matter...

Warm NPAC SSTs!

[Jesse]

Good call, I actually overlooked that one yesterday as I hurried through the data. 1967 was the warmest September on record statewide, and it should stay that way.

 

Also worth noting that though PDX may have inched their way to a monthly record, 90% of it was due to the warm lows. September 2014 wasn't even top 5 in Portland for average highs. I think that indicates that PDX's record results were an anomaly and largely UHI related.

I was perusing downtown's records and all of their record warm average September mins were 57.5 degrees or higher. Warmest ever September overall was 1974 with an average temp of 69.

 

PDX's (still somewhat) superior radiational cooling prowess has always prevented them from putting up numbers like that. But it is eroding.

[Deweydog]

Warm NPAC SSTs!

Persistence. It's not that hard to be warm.

[Jesse]

Persistence. It's not that hard to be warm.

 

We have certainly made it look easy the past several months.

 

It's not that hard to be cold either, if the pattern supports it. Persistence. Vagueness.

[BLI snowman]

Don't think it was anomaly... although if it was UHI then it would be something more permanent.    Here is Cliff's take:

 

http://cliffmass.blogspot.com/2014/09/minimum-temperature-heat-wave.html

 

It was certainly a warm month everywhere, but my point was that it doesn't appear likely that many or any rural stations set a monthly record. Years like 1974 for example, which had an incredible 500mb pattern, were hotter.

 

PDX set a record largely based on their increased difficulty in getting below 55 degrees nowadays during the summer, as opposed to their early decades

[Jesse]

It was certainly a warm month everywhere, but my point was that it doesn't appear likely that many or any rural stations set a monthly record. Years like 1974 for example, which had an incredible 500mb pattern, were hotter.

 

PDX set a record largely based on their increased difficulty in getting below 55 degrees nowadays during the summer, as opposed to their early decades

 

Bingo.

 

Doesn't tell the whole story since this September did indeed have very warm low temps regionally. But I think it's fair to say PDX's numbers are a little padded compared to previous decades at this point. Mainly in regard to MINs.

[Brennan]

HAs anyone heard of or from SnowmanJim?

[Jesse]

HAs anyone heard of or from SnowmanJim?

 

He's around. Waiting for a pattern change before he starts posting again.

[TT-SEA]

It was certainly a warm month everywhere, but my point was that it doesn't appear likely that many or any rural stations set a monthly record. Years like 1974 for example, which had an incredible 500mb pattern, were hotter.

 

PDX set a record largely based on their increased difficulty in getting below 55 degrees nowadays during the summer, as opposed to their early decades

 

Anecdotally... the nights seemed warmer this summer (and in September as well) at my house which I think is pretty well insulated from any UHI effect.  

 

In other words... I believe the pattern was more responsible than the UHI for the persistent warmth this summer.

[BLI snowman]

Bingo.

 

Doesn't tell the whole story since this September did indeed have very warm low temps regionally. But I think it's fair to say PDX's numbers are a little padded compared to previous decades at this point. Mainly in regard to MINs.

 

At Olympia, it looks like it was the 7th warmest. 3rd warmest for Bellingham. 6th warmest for Eugene. I think you'll see it finish in the 7 to 10 range for the region as a whole, the cool shot midmonth on the eastside also made a dent over there. 

[BLI snowman]

Anecdotally... the nights seemed warmer this summer (and in September as well) at my house which I think is pretty well insulated from any UHI effect.  

 

In other words... I believe the pattern was more responsible than the UHI for the persistent warmth this summer.

 

Obviously. Remember, I'm talking about the summer's historic standing only. The pattern was the key driver in the persistently warm temperature departures, but the scale of the departures themselves was often conditional this summer based on the UHI. September was a big example of that. 

 

That being said, I think it's fair to argue that for the region overall, it was the most persistently warm July/August/September since records began. Only a short list of years that really come close (1958, 1967, 1990, 1998). UHI or not, it's been impressive.

[Deweydog]

We have certainly made it look easy the past several months.

 

It's not that hard to be cold either, if the pattern supports it. Persistence. Vagueness.

What's vague? You've been here right?

[Jesse]

What's vague? You've been here right?

 

Yes, and the persistence has definitely been very persistent!

 

I'm thinking persistence is to blame.

[Deweydog]

Yes, and the persistence has definitely been very persistent!

 

I'm thinking persistence is to blame.

Well people still to seem to have issue dissecting it. When things are persistently warm, the numbers will probably reflect said warmth.

[Jesse]

Well people still to seem to have issue dissecting it. When things are persistently warm, the numbers will probably reflect said warmth.

 

I guess I want to dig a little deeper. What mechanisms have been causing the warmth to be so persistent? Besides persistence.

 

I would think the unusual patterns over the NPAC this year have played some role.

[Deweydog]

I guess I want to dig a little deeper. What mechanisms have been causing the warmth to be so persistent? Besides persistence.

Persistent mechanisms.

 

You may want persistent cold at some point so it should be comforting to know such persistence can persist.