July 2016 Observation and Model Discussion for the Pacific Northwest

[TT-SEA]

Looks pretty short lived to me as the ridge retrogrades to the GOA later in week 2.  I reserve the right to revise this however.

 

 

I am thinking it will be pretty warm on the east side of the mountains in August.   

 

Tougher call on this side.

[TT-SEA]

Windy out there.    

 

New ECMWF shows large band of convection (or at least rain) forming in SW WA and moving through the Seattle area early tomorrow morning just like previous runs and the WRF.

[Phil]

Didn't someone say a couple weeks ago that the last week of July would be warm?

Yes, I believe someone did. Again, congrats, you got this one right.

[ShawniganLake]

With northerly flow/downsloping? Around here, that'd knock dewpoints down 5-10 degrees, easy.

 

Heck, I've seen downsloping knock dews from 77 to 65 within an hour.

Downsloping makes lows even warmer here regardless of dewpoint.  A breezy night is about the only way it stays above 60 here locally.  I know many places on Vancouver Island can stay in the 70's with a north wind and warm airmass in the summer. 

[TT-SEA]

Yes, I believe someone did. Again, congrats, you got this one right.

 

I think I said the same thing about the last week of June well in advance.    Also about that pesky very troughy period in the first part of the month.   

 

Sort of feels like summer really started just after 7/15.  

 

This of course with the understanding that in the big picture you were far superior.  

[Phil]

Tough climate to forecast here.

 

I think using local history with the right analog years was a good approach. July happened to play out like a script laid out by similar years. Cold and damp in the first part of the month... even keel through the middle... warm in the end. The reverse of what the tropical forcing indicated in late June.

 

Might be good way to predict the future by looking at what actually happened here in similar situations in the past. Or maybe it just worked well this time.

 

We do it all the time in the winter with mixed results so maybe it works better in the relative stability of summer.

Actually, the tropical forcing w/ typical poleward lag would normally have predicted a warm 1st week of July, troughy/cool remainder of the month. Problem is, this year the poleward circulations are constructively feeding back w/ the forcing in such a manner that they're very receptive to stimuli w/ the same aforementioned construction.

 

Essentially, La Niña has the NPAC by the balls already. Usually don't see that until August.

[Geos]

Will be interesting to see if the ECMWF is correct on the convection in the AM.

 

Days 7-11 the warmest.

 

[Phil]

I think I said the same thing about the last week of June well in advance. Also about that pesky very troughy period in the first part of the month.

 

Sort of feels like summer really started just after 7/15.

Lol, I beat you in June dude.

 

You missed the early June heatwave, I didn't. Hence, I scored better overall in the forecast contest for that month, even at SEA where I nailed the +2.6 departure right on the nose.

 

Not bragging, just putting it out there.

[TT-SEA]

Actually, the tropical forcing w/ typical poleward lag would normally have predicted a warm 1st week of July, troughy/cool remainder of the month. Problem is, this year the poleward circulations are constructively feeding back w/ the forcing in such a manner that they're very receptive to stimuli w/ the same aforementioned construction.

 

Essentially, La Niña has the NPAC by the balls already. Usually don't see that until August.

 

That clearly happened in 1988 as well?

[Phil]

That clearly happened in 1988 as well?

Yes, 1988 locked in exceptionally early, even more-so than this year.

[TT-SEA]

Lol, you caved to me on June.

 

You missed the early June heatwave, I didn't. Hence, I scored better overall in the forecast contest for that month. In fact, I nailed SEA's departure right on the nose.

 

Yes... overall.

 

But at the end of the heat wave... I said probably 2 weeks of troughing and then the last week of June would be warm.     

 

Honestly... the heat wave in early June was when I knew my thoughts for summer were going to be wrong.   That is when I adjusted to your early regime change idea.

[GHweatherChris]

We had an unexpected very heavy rain shower move through about 20 minutes ago, our daughter decided it was a good time to run outside and play soccer in our backyard, so we did!

[TT-SEA]

Yes, 1988 locked in exceptionally early, even more-so than this year.

 

Really see similarities to 1988 this year.   Off by about a week.  

 

In 1988 there was deep troughing and cold weather late June to early July... then really warm for the entire second half of July.    Cool in early August and then more heat and ridging in the second half of August.  

 

If we have a similar situation this year running a week behind:

• Warm through the first 10 days of August
• Cool and troughy for a week in the middle of August
• Warm and ridgy from 8/20 well into September

[Geos]

Lightning lighting up the sky to the WNW with that cell near Port Townsend. 

[ShawniganLake]

Lightning lighting up the sky to the WNW with that cell near Port Townsend. 

I can see the same thing to my south, but it might be that cell over the Olympics.  That cell has been throwing out a ton of lightning. 

[TT-SEA]

Lightning lighting up the sky to the WNW with that cell near Port Townsend. 

 

 

[Geos]

I can see the same thing to my south, but it might be that cell over the Olympics.  That cell has been throwing out a ton of lightning. 

 

It's a nice show. Nice cloud to ground strike just now. Can actually hear the thunder off in the distance.

[Phil]

 

 

Really see similarities to 1988 this year. Off by about a week.

 

In 1988 there was deep troughing and cold weather late June to early July... then really warm for the entire second half of July. Cool in early August and then more heat and ridging in the second half of August.

 

If we have a similar situation this year running a week behind:

• Warm through the first 10 days of August
• Cool and troughy for a week in the middle of August
• Warm and ridgy from 8/20 well into September

The two problems with 1988 are the IO/IOD and solar forcing. Due to these differences, a wave-1 convective signature in the tropics developed early and persisted in 1988, while we've had a clear wave-2 signature this year.

 

So I wouldn't expect to follow 1988, especially in late August/September. I think a blend of the other wave-2 years (1995, 1983, and 1980) will work best overall from 8/15 to 9/15.

[ShawniganLake]

Victoria (YYJ) might pull off a midnight high tomorrow.  73F there at 11pm.  Average high this time of year is 72F there. 

[TT-SEA]

The two problems with 1988 are the IO/IOD and solar forcing. Due to these differences, a wave-1 convective signature in the tropics developed early and persisted in 1988, while we've had a clear wave-2 signature this year.

 

So I wouldn't expect to follow 1988, especially in late August/September. I think a blend of the other wave-2 years (1995, 1983, and 1980) will work best overall from 8/15 to 9/15.

 

Interesting.

 

September of 1995 was very warm here.    Top tier.

 

ECMWF shows a break down of the hot spell now at 240 hours.   If that trough verifies my guess is that it does not really dig down into the PNW but rather zips through BC.   Definitely would cool it down to normal or a little below.   Obviously we are not going to just stay hot.   But there will likely be more warm spells ahead.

 

http://stream.ecmwf.int/data/atls18/data/data01/scratch/ps2png-atls18-95e2cf679cd58ee9b4db4dd119a05a8d-oyHe8e.png

[Phil]

I like your initial call of troughing from 8/5-8/15. Personally would extend it to ~ 8/20 for the reasons in my earlier post.

 

The poleward WAFs out of the EPAC shut down during the 1st week of August, so the forcing for that ridge won't be there anymore, with the residual AAM propagating poleward as the next round of Niña forcing takes hold in the Pacific.

[VancouverIslandSouth]

Victoria (YYJ) might pull off a midnight high tomorrow.  73F there at 11pm.  Average high this time of year is 72F there. 

 

That area must have managed to stay sheltered. Things cooled off a bit here after the rain, it was around 70~72F now down to about 66F. It's still looking quite active over the Olympics.

[Jesse]

00z GFS ensembles hint at a pretty quick hitting heat wave.

 

[Phil]

Here's SEA on the 00z ECMWF. Final 6 days obviously the warmest relative to average.

 

 

Here's PDX. Hawt but possibly overdone given the range.

 

 

OT, but I thought the one bright side of you guys entering a period of ridging would be me getting into some troughing, but that's obviously not going to happen with the high hemispheric wavenumber. I'm really starting to hate this climate. Just relentless from July-September every d**n year.

 

[Geos]

Another cell has sparked off along the Hood Canal now. Throwing out visible lightning bolts.

[ShawniganLake]

That area must have managed to stay sheltered. Things cooled off a bit here after the rain, it was around 70~72F now down to about 66F. It's still looking quite active over the Olympics.

Up this way, the first few hours of the marine push are usually very mild.  Currently close to 70F here with a west wind gusting close to 25mph.  Occasionally we get a marine push that initiates in the late afternoon.  That initial burst of west wind will often spike the temp 3-6F in a short amount of time. I assume its downsloping off the hills to our west.  

 

http://www.victoriaweather.ca/stations/latest/temperature_all.all.png

[ShawniganLake]

Not really how it works with these types of setups. This one is pretty standard summer stuff here. The instability is mostly elevated above the boundary layer so our daytime surface heating/surface CAPE is a bit less relevant. Maintaining midlevel moisture and instability, convection will fire up overnight. Just a matter of proportion in regards to the track of upper level low. Often times the marine surge will even act like a low level jet and trigger in the late evening and overnight hours.

Nice call.

[MossMan]

Still 62 degrees with cloudy skies early this AM, heard some rumbling sometime in the middle of the night, but still nice and dry here as of now.

[snow_wizard]

00z GFS ensembles hint at a pretty quick hitting heat wave.

 

image.png

 

Yup.  Loving the fact that GOA ridge sets up again.

[The Swamp]

Should end up with some impressive rainfall totals here in the swamp. Wow!

 

Hope it clears up and warms up soon. My tomato plants are drowning.

[GobBluth]

Yup.  Loving the fact that GOA ridge sets up again.

06 seems even faster in collapsing the ridge over the nw

[TT-SEA]

Rain is right where the models showed last night.

 

[TT-SEA]

06 seems even faster in collapsing the ridge over the nw

 

 

06Z GFS ensemble mean does not show a big change in the long run... probably not going to crash too hard.

 

http://mp1.met.psu.edu/~fxg1/ENSHGTAVGNH_6z/f300.gif

[GobBluth]

06Z GFS ensemble mean does not show a big change in the long run... probably not going to crash too hard.

 

http://mp1.met.psu.edu/~fxg1/ENSHGTAVGNH_6z/f300.gif

Probably back into a constant onshore flow low 80s pattern. 

[TT-SEA]

.26 at SEA in the last 2 hours.

[Jesse]

Nice call.

Not for down here. That was in response to Matt and myself agreeing that best dynamics would be up north.

[MossMan]

The ground is just turning wet up here.

[Jesse]

Have been getting a good soaking all morning here. Very nice going into what will be some of our hottest weather of the summer so far.

 

I see PDX picked up 0.23 in the last hour.

[stuffradio]

Have been getting a good soaking all morning here. Very nice going into what will be some of our hottest weather of the summer so far.

 

I see PDX picked up 0.23 in the last hour.

I was happy to see rain this morning because I hilled up my potatoes on the weekend.

[TT-SEA]

.30 at SEA now... put them above normal for July rainfall.