August 2016 Observations and Model Discussion for the Pacific Northwest

[Jesse]

They just missed it, they have hit 89 a bunch of times already this year. Portland and Salem officially hit 89. Eugene and Troutdale hit 90 and Hillsboro hit 91.

Score!!

[Jesse]

Definitely liking the 06z ensembles:

 

[ShawniganLake]

We were driving through the desert areas SE of Cache Creek around 1am this morning and stopped to view the meteors. Pretty amazing view with clear skies, no light pollution, no trees, and no mountains too close to block your view. Probably could see 4-5 per minute at times. Even as we were driving we could notice them falling in front of us.

[Jesse]

We were driving through the desert areas SE of Cache Creek around 1am this morning and stopped to view the meteors. Pretty amazing view with clear skies, no light pollution, no trees, and no mountains too close to block your view. Probably could see 4-5 per minute at times. Even as we were driving we could notice them falling in front of us.

 

That sounds awesome. We are heading up towards Mount Adams tonight to do some viewing. It is pretty dark up there, although I'm not sure if it would be quite as dark as Interior BC.

[Front Ranger]

Sun angle and low level cold played a huge part in how those events unfolded, actually. Otherwise, from a strictly upper level standpoint, there have been several very comparable March airmasses to those in the airport era that produced -10c and even -15c or lower 850mb temps over the lowlands. 1955, 1976, and 1989 to name a few. 

 

Sun angle, or basically day time heating potential, yes. But the peak of those events, including Nov 2010 where SEA saw a high of 25 or 1985 where BLI saw a high of 15, had nothing to do with low level inversions. Those were well-mixed air masses. And we've seen nothing close in March for a long time.

[Jesse]

Most of next week has trended disturbingly cooler in recent runs.

[BLI snowman]

Sun angle, or basically day time heating potential, yes. But the peak of those events, including Nov 2010 where SEA saw a high of 25 or 1985 where BLI saw a high of 15, had nothing to do with low level inversions. Those were well-mixed air masses. And we've seen nothing close in March for a long time.

 

I wouldn't agree, 1985 in particular was still very low level influenced for places like Portland. 

 

http://mp1.met.psu.edu/~fxg1/NARR/1985/us1129.php

 

The 850mb temps down here bottomed out around -11c that month. We've seen similarly cold airmasses several times in March in the airport era.

[BLI snowman]

Most of next week has trended disturbingly cooler in recent runs.

 

Monday through Saturday still look like wall to wall 85+ with a couple of 95ish days thrown in for good measure.

 

Looks like the peak of our summer.

[Jesse]

Monday through Saturday still look like wall to wall 85+ with a couple of 95ish days thrown in for good measure.

 

Looks like the peak of our summer.

Perhaps. MOS guidance now has PDX in the low 80s Sunday-Wednesday. And they are usually no more than a few degrees off.

 

Late next week is still pretty up in the air.

[Front Ranger]

I wouldn't agree, 1985 in particular was still very low level influenced for places like Portland. 

 

http://mp1.met.psu.edu/~fxg1/NARR/1985/us1129.php

 

The 850mb temps down here bottomed out around -11c that month. We've seen similarly cold airmasses several times in March in the airport era.

 

I'm looking at the region overall, not just Portland. 

 

Yes, there were parts of 1985 that were mainly low level cold. But when you look at the overall air masses of 2010, 1985, 1955, hell even 2006 up north, there hasn't been anything close in March for a long time.

[Deweydog]

Most of next week has trended disturbingly cooler in recent runs.

What were you expecting?

[Jesse]

Something like this, of course.

 

[Deweydog]

Something like this, of course.

 

image.png

Gotta start thinking on your own, my man. Especially with climo lying on the ground outside the window in a thousand pieces.

[Jesse]

Gotta start thinking on your own, my man. Especially with climo lying on the ground outside the window in a thousand pieces.

 

I was being a bit sarcastic. I've been thinking his forecast for next week has been running too warm for a few days now.

[Deweydog]

 

I was being a bit sarcastic. I've been thinking his forecast for next week has been running too warm for a few days now.

He already tanked this morning's low...

[Jesse]

He already tanked this morning's low...

 

He does really well in the short term, generally skews a little warm past days 3-4.

 

It is pretty consistent.

[Deweydog]

He does really well in the short term, generally skews a little warm past days 3-4.

 

It is pretty consistent.

Run the #'s.

 

This is gonna be a lot of work.

[Jesse]

Run the #'s.

 

This is gonna be a lot of work.

 

Can't access old 7-days unless you save or screen shot them.

 

I guess I could for the one I just posted.

[Phil]

12z GFS likes the retrogression idea in the long range. FWIW, looks exactly like pattern analogs for Niña backgrounds w/ deamplifying WPAC forcing under weakening MJO dominance in face of lowfreq assertion.

[Deweydog]

Can't access old 7-days unless you save or screen shot them.

 

I guess I could for the one I just posted.

Perhaps a strongly-worded letter to the station manager at KPTV is in order.

[BLI snowman]

I'm looking at the region overall, not just Portland. 

 

Yes, there were parts of 1985 that were mainly low level cold. But when you look at the overall air masses of 2010, 1985, 1955, hell even 2006 up north, there hasn't been anything close in March for a long time.

 

Like I said, 1989, 1976, and 1955 were all fairly comparable March airmasses that dropped 850mb temps below -10c over western WA and OR. You also have 1971, 1960, and late March 1954. 

 

November 1955 was a true freak of nature, but otherwise UIL's coldest March airmasses are very in line with their coldest November airmasses

 

http://www.crh.noaa.gov/images/unr/soo/T850/low50-T850.pdf

[Jesse]

Perhaps a strongly-worded letter to the station manager at KPTV is in order.

 

Don't care that much.

 

It is what it is.

[Jesse]

Loving the trends for the last 1/3 of the month:

 

If the ensemble mean is close to accurate we are at our peak at 850mb today. 

[Deweydog]

Don't care that much.

 

It is what it is.

I suspect it's a subjective perception issue. He's still the most aggressive forecaster of any when it comes to the long range. There just aren't typically that many opportunities to go sexy cold these days. I still remember December 2008 when he had the week of the 14th entirely in the 20's. Sure looked sexy, but it sure didn't verify.

[Jesse]

I suspect it's a subjective perception issue. He's still the most aggressive forecaster of any when it comes to the long range. There just aren't typically that many opportunities to go sexy cold these days. I still remember December 2008 when he had the week of the 14th entirely in the 20's. Sure looked sexy, but it sure didn't verify.

 

Good points here. 

[Geos]

Special Wx statement out for Western Washington today. 

 

 

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE SEATTLE WA
338 AM PDT FRI AUG 12 2016

WAZ001-503-504-506-507-509>517-555-556-558-559-567>569-122300-
SAN JUAN COUNTY-WESTERN WHATCOM COUNTY-SOUTHWEST INTERIOR-
WESTERN SKAGIT COUNTY-EVERETT AND VICINITY-TACOMA AREA-
ADMIRALTY INLET AREA-HOOD CANAL AREA-LOWER CHEHALIS VALLEY AREA-
OLYMPICS-EASTERN STRAIT OF JUAN DE FUCA-
WESTERN STRAIT OF JUAN DE FUCA-NORTH COAST-CENTRAL COAST-
EAST PUGET SOUND LOWLANDS-BELLEVUE AND VICINITY-SEATTLE AND VICINITY-
BREMERTON AND VICINITY-CASCADES OF WHATCOM AND SKAGIT COUNTIES-
CASCADES OF SNOHOMISH AND KING COUNTIES-
CASCADES OF PIERCE AND LEWIS COUNTIES-
338 AM PDT FRI AUG 12 2016

...VERY WARM TEMPERATURES EXPECTED ACROSS MUCH OF WESTERN
WASHINGTON TODAY AND SATURDAY...

A RIDGE OF HIGH PRESSURE BUILDING OVER THE PACIFIC NORTHWEST WILL
PROVIDE SUNNY SKIES AND MUCH WARMER TEMPERATURES TODAY AND
SATURDAY. HIGH TEMPERATURES TODAY WILL REACH THE MID TO UPPER 80S
ACROSS MOST INTERIOR LOWLANDS...AND NEAR 90 IN THE SOUTHWEST
INTERIOR. TODAY WILL LIKELY BE THE WARMEST DAY AT THE COAST WHERE
HIGHS COULD REACH THE LOW 80S. TYPICALLY COOLER AREAS NEAR THE
WATERS OF THE NORTH INTERIOR AND STRAIT OF JUAN DE FUCA WILL TOP
OUT IN THE UPPER 70S.

ONSHORE FLOW DEVELOPS ALONG THE COAST SATURDAY WITH COOLER HIGH
TEMPERATURES ONLY REACHING THE UPPER 60S TO AROUND 70. HOWEVER...IT
WILL BE ANOTHER VERY WARM DAY INLAND WITH HIGHS GENERALLY REACHING
INTO THE MID TO UPPER 80S...EXCEPT LOWER 90S POSSIBLE OVER THE
SOUTHWEST INTERIOR AND EAST PUGET SOUND LOWLANDS. AREAS NEAR THE
WATER NORTH OF EVERETT WILL AGAIN STAY COOLER IN THE UPPER 70S.

IT WILL ALSO BE QUITE WARM IN THE MOUNTAIN VALLEYS AND PASSES WITH
HIGHS ALSO IN THE 80S FRIDAY AND SATURDAY. LOW TEMPERATURES DURING
THE PERIOD WILL PROVIDE SOME RELIEF OVERNIGHT WITH MAINLY MID TO
UPPER 50S...EXCEPT LOWER 60S IN THE SEATTLE METRO AREA.

THE VERY WARM TEMPERATURES MAY TEMPT INDIVIDUALS TO GO ONTO THE
AREA WATERWAYS. PLEASE BE AWARE THAT THE RIVERS AND WATERS ARE
STILL COLD. DEATHS DURING WARM SPELLS ACROSS THE PACIFIC
NORTHWEST OFTEN OCCUR FROM DROWNING DUE TO THE COLD WATER.

THE ELDERLY...AND THOSE WITH EXISTING HEALTH CONCERNS...SHOULD
REMAIN HYDRATED AND ATTEMPT TO STAY IN A COOL PLACE DURING THE
HEAT OF THE DAY.

 

 

 

Already at 76° here. Dew point at 63° is making it feel a little bit sticky.

[Jesse]

Pretty epic retrogression on the 12Z EURO.

 

Would love to see that verify.

[Front Ranger]

Like I said, 1989, 1976, and 1955 were all fairly comparable March airmasses that dropped 850mb temps below -10c over western WA and OR. You also have 1971, 1960, and late March 1954. 

 

November 1955 was a true freak of nature, but otherwise UIL's coldest March airmasses are very in line with their coldest November airmasses

 

http://www.crh.noaa.gov/images/unr/soo/T850/low50-T850.pdf

 

You're focusing on 850s now. I was simply responding to your assertion that the November air masses were colder on the ground due to inversions. Sun angle/longer days yes, inversions not so much. 

[Front Ranger]

Pretty epic retrogression on the 12Z EURO.

 

Would love to see that verify.

 

Yeah, it's a little warmer over the next week, but then big-time crash later on.

[BLI snowman]

You're focusing on 850s now. I was simply responding to your assertion that the November air masses were colder on the ground due to inversions. Sun angle/longer days yes, inversions not so much. 

 

Eh? The dynamics behind our inversion season literally go hand in hand with sun angle. You can't have one  aspect without the other. 

 

Our inversion season runs from roughly October 20 to February 20, when the sun angle is -10 degrees or lower over Portland. November is entering the heart of that season, again, due to sun angle. The sun isn't strong enough to mix out the air. It's just that simple, and it will have a noticeable impact on our weather after a cold front.

[Front Ranger]

Eh? The dynamics behind our inversion season literally go hand in hand with sun angle. You can't have one  aspect without the other. 

 

Our inversion season runs from roughly October 20 to February 20, when the sun angle is -10 degrees or lower over Portland. November is entering the heart of that season, again, due to sun angle. The sun isn't strong enough to mix out the air. It's just that simple, and it will have a noticeable impact on our weather after a cold front.

 

Again, the coldest parts of the Nov 1955, 1985 and 2010 events were well-mixed. There weren't inversions.

 

Shorter days does mean a smaller opportunity for day-time heating, and that has an effect everywhere.

[Phil]

Maybe Tim is onto something w/ the Canadian picking up on pattern changes before other guidance.

 

If the retrogression does occur (as I'm expecting it to), yesterday's 12z Canadian was once again the first to sniff it out, similar to how it sniffed out the slow ULL.

[Jesse]

Maybe Tim is onto something w/ the Canadian picking up on pattern changes before other guidance.

 

If the retrogression does occur (as I'm expecting it to), yesterday's 12z Canadian was once again the first to sniff it out, similar to how it sniffed out the slow ULL.

 

I think both the Canadian and EURO will take turns doing that. The GFS, less so. It's mainly a follower model these days it seems. One reason I look at the GFS ensembles just as much if not more than the operational.

[BLI snowman]

Again, the coldest parts of the Nov 1955, 1985 and 2010 events were well-mixed. There weren't inversions.

 

Shorter days does mean a smaller opportunity for day-time heating, and that has an effect everywhere.

 

That's only true for 2010. That was a quick-hitter. 1985 and 1955 both had healthy low level inversions develop after the initial CAA. Which wouldn't have been possible a few months later. 

 

And those were all incredibly anomalous events from a regional perspective, akin to something like March 1906 or March 1960 if you're looking at the opposing end of the season. 

[Front Ranger]

That's only true for 2010. That was a quick-hitter. 1985 and 1955 both had healthy low level inversions develop after the initial CAA. Which wouldn't have been possible a few months later. 

 

And those were all incredibly anomalous events from a regional perspective, akin to something like March 1906 or March 1960 if you're looking at the opposing end of the season. 

 

So the day BLI saw a high of 15 in Nov 1985 was due to an inversion? OLM's 24/12 day on 11/12/55?

[BLI snowman]

So the day BLI saw a high of 15 in Nov 1985 was due to an inversion? OLM's 24/12 day on 11/12/55?

 

The 1955 event was low level based by the 15th or so.

 

And there was clearly a low level cold pool developing by this point in the 1985 event, followed by an upper level reload which was in fact a more low level seepage oriented event. 

 

http://mp1.met.psu.edu/~fxg1/NARR/1985/us1124.php

 

It's entirely inaccurate to say that neither event featured inversions or low level cold pools develop. As I said before, a few months later that type of progression would not have been possible. 

[Deweydog]

So the day BLI saw a high of 15 in Nov 1985 was due to an inversion? OLM's 24/12 day on 11/12/55?

A great deal of 1985's greatness was outflow related, disproportionate to the amount of upper level cold. It's pretty established this is a dynamic which is directly related to inversion season.

[Jesse]

The 12Z EURO ensembles look cooler overall than even the operational from the middle of next week onward.

 

This feels very similar to what happened in late July. Hopefully persistent offshore ridging keeps being a prominent pattern driver like this through the Fall and Winter.

[FroYoBro]

Pretty epic retrogression on the 12Z EURO.

 

Would love to see that verify.

Retrogressions can only be epic in the winter. 

[Front Ranger]

The 1955 event was low level based by the 15th or so.

 

And there was clearly a low level cold pool developing by this point in the 1985 event, followed by an upper level reload which was in fact a more low level seepage oriented event.

 

http://mp1.met.psu.edu/~fxg1/NARR/1985/us1124.php

 

It's entirely inaccurate to say that neither event featured inversions or low level cold pools develop. As I said before, a few months later that type of progression would not have been possible.

I didn't say neither event featured low level inversions. You must have misunderstood. I was talking about the peaks of those events, the coldest days, ie those days I referenced in each event. And you avoided my question about those particular days.

 

March hasn't produced anything like those well-mixed days in a very long time. And I just don't think there's any easy explanation for why the early cold season (Nov-Dec) has produced much more impressive air masses relative to average than later in the cold season (Jan-Mar). It's a well documented phenomenon for the past several decades.