August 2017 PNW Discussion Thread

[Phil]

Discussing the models. They changed. A 1977-like flip looked to be on the table early on in the month. By mid month the writing was on the wall that things would run very warm overall.

Where's my credit, dam*it?!

[TT-SEA]

Where's my credit, dam*it?!

 

If September is warm and dry here then I will be giving you major kudos... that does not seem likely given the evolution this summer so it would be a great prediction if it works out.

[Jesse]

Where's my credit, dam*it?!

 

Cancelled out by your busted June/July.

[Phil]

If September is warm and dry here then I will be giving you major kudos... that does not seem likely given the evolution this summer so it would be a great prediction if it works out.

I was wrong back in June, so it could easily happen again. My screw ups tend to cluster together (usually when the QBO is between phases, since I rely on it for multi-month forecasts), so I'm still wary about getting over-confident again.

 

I'm more confident in a warm September than a dry one, mostly thanks to a developing WPAC MJO event. There will be a significant diabatic heat release from the resulting typhoon train that ignites over those scorching warm pool SSTs, under the convectively active domain of the MJO. Looks similar to last August in terms of the tropical forcing, though -QBO will play differently on the extratropical wavetrains.

[Phil]

The MJO should reach the WPAC during the second week of September, so I'm watching for another strong ridge and heat spike between 9/10 and 9/20.

[Jesse]

The MJO should reach the WPAC during the second week of September, so I'm watching for another strong ridge and heat spike between 9/10 and 9/20.

 

Seems like we will be getting one this weekend into early next week as well. Any WPAC forcing involved there? Or is this one just for shits and giggles.

[TT-SEA]

Models picking up on a hurricane meandering around SE Texas and Louisiana early next week.   The GFS has it coming into south Texas and then going back out in the Gulf of Mexico and moving north into Louisiana.  

 

Here is the 00Z ECMWF for next Monday...

 

[Front Ranger]

Comparing the Puget Sound to the Willamette Valley can be a bit of an apples/oranges affair. July 1958 was favored for the Puget Sound. Incredible anomalies. Monroe pulled off an 87.7 mean maximum for the month, almost 4F higher than any other month on record. Even Clearbrook averaged 85.1 for a max. 

 

On the other hand, PDX averaged "only" 83.5, and Eugene's 87.5 came in lower than Monroe. In 2014 alone, EUG averaged warmer maximums in both July (87.6) and August (87.8). July 1958 isn't the standard bearer for the Willamette Valley like it is in the Puget Sound. 

 

The point wasn't about the exact month, but rather this month vs. all-time record warm month. 

 

Since you brought up EUG, they are also running about 1.5 degrees cooler than their all-time record warm month.

[Front Ranger]

If September is warm and dry here then I will be giving you major kudos... that does not seem likely given the evolution this summer so it would be a great prediction if it works out.

 

Agreed. A warm/dry September happened in about 1/3 of the main analogs I've liked since late July, so it certainly wouldn't shock me, but I don't think it's the most likely outcome.

 

A warm/wet September like 2013 would really throw a wrench in the kudo-giving!

[Phil]

Seems like we will be getting one this weekend into early next week as well. Any WPAC forcing involved there? Or is this one just for shits and giggles.

The expanded WPAC warm pool is part of the reason for it, with a well-timed rossby wave packet responsible for the rest.

[Phil]

The 12z GFS dumps 40-50"+ of rain on Houston, TX. Yikes.

[Phil]

Agreed. A warm/dry September happened in about 1/3 of the main analogs I've liked since late July, so it certainly wouldn't shock me, but I don't think it's the most likely outcome.

 

A warm/wet September like 2013 would really throw a wrench in the kudo-giving!

Are you still calling for a cooler than average September?

[TT-SEA]

Labor Day weekend looking hot on the 12Z GFS.   Might complete the trifecta of warm, dry weather on all three of the summer holidays this year.

 

[wx_statman]

The point wasn't about the exact month, but rather this month vs. all-time record warm month. 

 

Since you brought up EUG, they are also running about 1.5 degrees cooler than their all-time record warm month.

 

It's also currently not the warmest month on record at PDX, albeit we're only running 0.3F behind July 1985. The good old UHI is propping up PDX minimums, so no shocker there. 

[Jesse]

It's also currently not the warmest month on record at PDX, albeit we're only running 0.3F behind July 1985. The good old UHI is propping up PDX minimums, so no shocker there.

Pretty hard to imagine a scenario where the heat forecast for the 27th-29th doesn't put them over the top, though.

 

Do you think present day PDX would have run appreciably warmer in August of 1967?

[Front Ranger]

Are you still calling for a cooler than average September?

 

Still sticking with September having the coolest anomalies of the summer, which is what I've been going with since May. Average to a little cooler than average.

 

I haven't analyzed anything since the last time I looked at the pattern progression/analogs, which was a couple weeks ago.

[Front Ranger]

It's also currently not the warmest month on record at PDX, albeit we're only running 0.3F behind July 1985. The good old UHI is propping up PDX minimums, so no shocker there. 

 

Yep, that was basically my point, differences between record warm months in the Willamette Valley vs. Puget Sound aside.

[James Jones]

Pretty hard to imagine a scenario where the 27th-29th don't put them over the top, though.

 

Do you think present day PDX would have run appreciably warmer in August of 1967?

 

PDX averaged 88.1 / 57.7 while downtown averaged 88.5 / 61.4. The UHI effect at the present day PDX is probably not as strong as the old downtown station but I think it's a decent approximation for what modern day PDX might have done in 1967.

 

One difference is that 8/1967 had generally lower dewpoints than this one so that would help exaggerate the UHI effect.

[Phil]

Still sticking with September having the coolest anomalies of the summer, which is what I've been going with since May. Average to a little cooler than average.

 

I haven't analyzed anything since the last time I looked at the pattern progression/analogs, which was a couple weeks ago.

So, a "clear" cool west, warm Midwest/East?

 

The big change I would now make is for September. I think the likelihood of a warm September in the West (including the PNW) has gone down significantly. Primary analogs now show a clear cool West/warm Midwest East signal for September.

[Phil]

[Front Ranger]

PDX averaged 88.1 / 57.7 while downtown averaged 88.5 / 61.4. The UHI effect at the present day PDX is probably not as strong as the old downtown station but I think it's a decent approximation for what modern day PDX might have done in 1967.

 

One difference is that 8/1967 had generally lower dewpoints than this one so that would help exaggerate the UHI effect.

 

Yeah, it depends on the station, but 1-3 degrees tends to be the amount of UHI warming many such stations have seen. So that would match up with those numbers.

[Front Ranger]

So, a "clear" cool west, warm Midwest/East?

 

The majority of analogs I looked at a few weeks ago still showed that. Though the first 3 weeks of this month unfolded fairly close to what I was expecting, I would like to see some sort of western troughing signal show up over the next couple weeks in the models. I'll try to look at things closer sometime in the next week and make an updated post in the summer predictions thread.

[SilverFallsAndrew]

Why not extreme SE Oklahoma in 7 years?

 

Dallas gets almost 4 minutes of totality on 4/8/2024... and just east of Dallas its well over 4 minutes.

 

Yes, I am almost definitely going to go to this one. Given 3 of my kids live in Oklahoma, they will be 11 and 9 in 2024 too, so definitely an age when they can enjoy it. And then look forward to 2045 . 

[SilverFallsAndrew]

Another hot August...The beat goes on...I am just working on getting through it and on to Fall/Winter. With a weak Nina in play perhaps we get the goods. 

[BLI snowman]

Pretty hard to imagine a scenario where the heat forecast for the 27th-29th doesn't put them over the top, though.

 

Do you think present day PDX would have run appreciably warmer in August of 1967?

 

Easily.

 

Downtown had a 61.45 mean minimum that month while PDX was 57.68. This month so far PDX is at 60.14 and downtown is at 60.94. The disparity has lessened considerably.

[Front Ranger]

The 12z GFS dumps 40-50"+ of rain on Houston, TX. Yikes.

 

Euro also shows a slow, meandering track that would likely result in severe flooding for that area.

[TT-SEA]

Euro also shows a slow, meandering track that would likely result in severe flooding for that area.

 

 

Total rain per 12Z ECMWF over the next week...

 

[Jesse]

Easily.

 

Downtown had a 61.45 mean minimum that month while PDX was 57.68. This month so far PDX is at 60.14 and downtown is at 60.94. The disparity has lessened considerably.

I can never figure out how to check current monthly observations at Downtown. Is it in the NowData?

[BLI snowman]

I can never figure out how to check current monthly observations at Downtown. Is it in the NowData?

 

Yes, also viewable on WRCC's page.

[Jesse]

12Z EURO slices the next heat event down to two or so days. Looks like it is getting ready to build another strong ridge in toward day 10, though.

[Timmy]

Looks like it's trying to rain in Portland now

[Jesse]

Looks like it's trying to rain in Portland now

Looks to be trending east.

[Jesse]

The fire on upper Eagle Creek, in the Gorge, has tripled in acreage the last few days. Could be a pretty bad situation if we get some east wind driven heatwaves in the first few weeks of September.

[Deweydog]

The 75 streak is in some serious hot water tomorrow.

[wx_statman]

Saw a few warm raindrops downtown a little earlier. 

[Anti Marine Layer]

I see Poway has not broken out of the marine layer clouds yet. What month is it again?

[Front Ranger]

I see Poway has not broken out of the marine layer clouds yet. What month is it again?

 

What thread is this again?

 

[wx_statman]

Pretty hard to imagine a scenario where the heat forecast for the 27th-29th doesn't put them over the top, though.

 

Do you think present day PDX would have run appreciably warmer in August of 1967?

 

I'm sure it would have. PDX managed a 57.7 minimum average in August 1967, more than 2F lower than this month. 

[Deweydog]

Virga!!!

[Jesse]

The 75 streak is in some serious hot water tomorrow.

76-77 at PDX tomorrow. Mild start, sunny afternoon.