August 2017 PNW Discussion Thread

[luminen]

Why's that? Our biggest snow usually comes from temps around -2 to 1C.

 

I like big snows as much as the next guy but bitter cold is where it's at, as long as there is 2"+ on the ground. Add some strong winds to the mix and... 

 

Looking like I'll get 0.50" of rain with this next system...

[DareDuck]

Today was our 56th consecutive day at or above 80 and 17th at or above 90. I believe we're also at 40 total 90+ plus days. However, no days above 100 in Bend so far. Looks to come to an end tomorrow thankfully.

[GHweatherChris]

Holy , it's raining!!!

[VancouverIslandSouth]

Holy s**t, it's raining!!!

 

Looks like a fairly robust front on the radar. So long smokey skies!

[TT-SEA]

Looks like a fairly robust front on the radar. So long smokey skies!

 

Air quality is already good across the region.   But it will be nice to have a real front for extra measure.  

 

So glad we missed the entire smoke event... it just started when we were leaving and it cleared up just as we came home.   I saw enough smoke on web cams though to know how bad it was here.

[VancouverIslandSouth]

Air quality is already good across the region.   But it will be nice to have a real front for extra measure.  

 

So glad we missed the entire smoke event... it just started when we were leaving and it cleared up just as we came home.   I saw enough smoke on web cams though to know how bad it was here.

 

It started noticably clearing out here yesterday and low level air quality improved but today was the first time in over a week I've seen the Olympic Mountains. This front should clear up whatever was left. It's Alberta's turn now:

 

http://i.imgur.com/H7MGAUK.png

[TT-SEA]

Got home in time to do some harvesting in the garden before it got dark tonight.   The garden did awesome despite not being watered for the last week... and actually everything grew by leaps and bounds.   Our tomato plants were about 5 feet tall when we left and now they are about 8 feet high.  We have tons of zucchini about ready to pick now as well.

 

Peas and beans and potatoes and lots of dahlias were picked tonight...

 

[Front Ranger]

The beneficial aspects of smoke to gardens are really underrated.

[TT-SEA]

The beneficial aspects of smoke to gardens are really underrated.

 

Hard to argue with the results!   

 

Actually... the smoke might have keep the evaporation of moisture down a little.   It definitely took the edge off the heat wave.  

[TT-SEA]

The 00Z GFS is the complete opposite of its 12Z run for next weekend... much more troughy and cool.   

[Geos]

Nice to see rain on the radar again. Was a nice day today.

[Jesse]

The 00Z GFS is the complete opposite of its 12Z run for next weekend... much more troughy and cool.

Good.

[TT-SEA]

Front is shearing apart... might not amount to much.

[wx_statman]

Around what time does PDX see the biggest drop in its % of days at or above 90?

 

Looks like it's from August 9th (25%) to August 16th (9%). In other words, right now. 

[Jesse]

Looks like it's from August 9th (25%) to August 16th (9%). In other words, right now.

Interesting. This kind of backs up what I was trying to say yesterday. Right around now is when things start moving in the other direction.

[wx_statman]

Interesting. This kind of backs up what I was trying to say yesterday. Right around now is when things start moving in the other direction.

 

Yes, this is also the time of year when our average temp starts dropping. 

[Jesse]

Yes, this is also the time of year when our average temp starts dropping.

Now I'm curious about when the % chance 100+ days peaks. How exactly do you pull up the chart that makes this sort of thing relatively easy to calculate, again?

[wx_statman]

Now I'm curious about when the % chance 100+ days peaks. How exactly do you pull up the chart that makes this sort of thing relatively easy to calculate, again?

 

Go to the NOWData page on the Portland NWS site. This is what your query should look like:

[wx_statman]

I wish there was a way to look up streaks. I'm thinking about importing a csv file of PDX max/min data into R (the statistical software). I can probably figure out a way to run a consecutive days function in there. 

[VancouverIslandSouth]

Hard to argue with the results!   

 

Actually... the smoke might have keep the evaporation of moisture down a little.   It definitely took the edge off the heat wave.  

 

The evaporation rate seemed considerably lower last week with the smoke filtering the sun. My wife filled a bird bath during the thick of it and it took about 5 days to evaporate. With smokeless summer days it typically evaporates in 2~3 days.

 

Still I'm glad to see it gone, Victoria proper just recorded its first measureable rain in 21 days. Victoria airport the first in what I believe is 55 days, which sets a new record for longest dry streak.

[Jesse]

Go to the NOWData page on the Portland NWS site. This is what your query should look like:

 

Thank you! Looks like it peaks on both August 8th and 11th, with a 5.3% occurrence rate on both of those days.

 

95+ days peak on the 8th and 10th of August, with 11.8% occurrence rate for both of those days.

 

Seems that for both of these thresholds there is a gradual buildup staring around the middle of July, then a sharp drop off moving past the second week of August.

[Phil]

I wish there was a way to look up streaks. I'm thinking about importing a csv file of PDX max/min data into R (the statistical software). I can probably figure out a way to run a consecutive days function in there.

If you have time, you could check to see if you can find a diffraction pattern in the spatial distribution of the 100+ readings. I've found this pattern in a number of stations around here in the summer, almost like the interference pattern observed in the double slit experiment.

[wx_statman]

If you have time, you could check to see if you can find a diffraction pattern in the spatial distribution of the 100+ readings. I've found this pattern in a number of stations around here in the summer, almost like the interference pattern observed in the double slit experiment.

 

I'm not just talking about 100 degree streaks...any streaks. For example, if I wanted to figure out the most consecutive days with maximums below 58 (random example), I could call it up with a function. 

[wx_statman]

Thank you! Looks like it peaks on both August 8th and 11th, with a 5.3% occurrence rate on both of those days.

 

95+ days peak on the 8th and 10th of August, with 11.8% occurrence rate for both of those days.

 

Seems that for both of these thresholds there is a gradual buildup staring around the middle of July, then a sharp drop off moving past the second week of August.

 

I posted some results a week ago in a different thread:

 

http://theweatherforums.com/index.php/topic/1400-unusual-weather-trivia-that-is-hard-to-google/?p=249684

 

Since that time, August 9th has moved from 24% to 25% probability of 90 degrees...94 on Wednesday. 

[ShawniganLake]

Tough day for BC fire fighters. Strong winds, lightning, dry fuels have pushed fires past guard lines and started new fires and brought new evacuations.

 

The Elephant hill fire has progressed significantly to the North and towards our Property in that area. Not sure how close it has moved but I am hearing that they have moved structural protection units into the southern sections of our community.

 

This picture was taken along Hwy20, understandably that highway has been closed.

[Phil]

To open the upcoming cold season, NH snowcover remains approximately +2 standard deviations above normal, for the 20yr record period of higher resolution satellite observations.

 

[TT-SEA]

The dry streak at SEA ends with precip recorded on just a single hourly observation with a total of .02 for the event.

 

And only .08 here so far... although it is still drizzling. 

 

Very disappointing totals from what looked like a fairly robust front.  

[Phil]

Note the subsidence centered over the northern periphery of the WPAC warm pool on the GFS/GEFS.

 

https://www.tropicaltidbits.com/analysis/models/?model=gfs&region=global&pkg=chi200&runtime=2017081306&fh=-114&xpos=0&ypos=304

 

The MJO is temporarily suppressing the multidecadal tendency for increased off-equator (NH based) WPAC convection. This will promote a waveguide that favors a trough anomaly over western North America until the MJO propagates into the Pacific during early or middle September.

[Phil]

[Phil]

FWIW, I believe the chances of a mid-September heatwave are also elevated this year, given the MJO periodicity and pronounced WPAC warm pool and low frequency +PMM circulation.

[stuffradio]

It rained overnight, but not much. I haven't checked the manual rain gauge yet, but my weather station is only reporting 0.03 inches. There was a power outage too for a few minutes.

[Anti Marine Layer]

The dry streak at SEA ends with precip recorded on just a single hourly observation with a total of .02 for the event.

 

And only .08 here so far... although it is still drizzling. 

 

Very disappointing totals from what looked like a fairly robust front.  

 

Very much like most of California's "storms" in the winter seasons before this year. Even the ones that looked like they could bring some good rain would always fizzle out at the last minute,

[Timmy]

The dry streak at SEA ends with precip recorded on just a single hourly observation with a total of .02 for the event.

 

And only .08 here so far... although it is still drizzling.

 

Very disappointing totals from what looked like a fairly robust front.

I don't think it was ever supposed to amount to anything at least down here

[Phil]

I guess a wildcard could be Atlantic hurricane activity later this month. With sufficient extratropical diabatic heat release, the NATL wavetrain/NAO (et al) could be altered enough to destructively interfere with any MJO-forced Western NAMR ridge, at least for a time. It would require a perfectly timed major hurricane(s), though, between August 20th - 28th, right before the MJO enters the WPAC again in September.

[TT-SEA]

I don't think it was ever supposed to amount to anything at least down here

 

I was expecting at least a widespread .25 for most areas up here based on the models over the past couple days.

[Phil]

I guess a wildcard could be Atlantic hurricane activity later this month. With sufficient extratropical diabatic heat release, the NATL wavetrain/NAO (et al) could be altered enough to destructively interfere with any MJO-forced Western NAMR ridge, at least for a time. It would require a perfectly timed major hurricane(s), though, between August 20th - 28th, right before the MJO enters the WPAC again in September.

So I'd lean warm to very-warm in the PNW for September, but it's definitely not as straightforward this time, compared to August which was almost a slam dunk, even 6+ weeks out.

 

Then in late September into October, we'll have to see whether the Eurasian circulation transitions quickly into the winter state an we develop a stronger Siberian High (good sign for cooler weather/blocking heading into cold season and a cooler PNW in most cases) or maintain the monsoonal circulation for longer like most recent years (warm signal for PNW during -QBO years via +EPO/wave dispersion in NPAC).

[Phil]

Also, I cannot emphasize how important it is (IMO) that we avoid major geomagnetic storms/proton blasts in Sep/Oct/Nov during a -QBO fall/winter, just a few years removed from solar max.

 

The conduits to NH blocking during -QBO winters are more coherent and accessible vs +QBO winters, but getting the cold/blocking to favor North America (as opposed to Eurasia) is much more challenging under -ENSO bias.

 

The cases of successful PNW winters under -QBO/-ENSO are almost exclusively confined to weak solar wind years in the modern climate era. The system is just now beginning the transition out of its solar-max Pacific circulation (started back in M/A/M this year), so we'd like the fastest transition possible. Unlike the +QBO boundary state, which favors a strong/poleward NPAC high in nearly all cases, the -QBO years can easily go nuclear with the +EPO/GOA vortex if the NAM/strat are pulled positive.

 

Given the systematic transition out of the solar maximum circulation is just beginning, IMO we don't want to upset the process by crippling the BDC/cooling the upper stratosphere before the cold season NAM conduits open/mature (usually around the holidays).

[Jesse]

A refreshing, fine drizzle here this morning.

[TT-SEA]

So I'd lean warm to very-warm in the PNW for September, but it's definitely not as straightforward this time, compared to August which was almost a slam dunk, even 6+ weeks out.

 

Then in late September into October, we'll have to see whether the Eurasian circulation transitions quickly into the winter state an we develop a stronger Siberian High (good sign for cooler weather/blocking heading into cold season and a cooler PNW in most cases) or maintain the monsoonal circulation for longer like most recent years (warm signal for PNW during -QBO years via +EPO/wave dispersion in NPAC).

 

It does not feel like a warm to very warm September coming... that is just intuition based on local history and not scientific in any way.     

 

Although I have been wrong many times before using that method.

[TT-SEA]

12Z GFS and 12Z GEM both significantly backed off on the troughing for next weekend that their 00Z runs showed.