Weather Blog

State's drought could spell early end to autumn leaves displays

State's drought could spell early end to autumn leaves displays
Photo courtesy: Meg McDonald, Wild Northwest Beauty Photography

So in driving around town this September, it seemed to my untrained eye that the autumn leaves were turning earlier than usual, with some trees already golden brown or red and half empty. Could it be a by-product of the hot summer?

I asked some experts at the University of Washington Botanical Gardens and it turns out it's yes and no.

First of all, according to Dr. Sarah Reichard, the director of the University of Washington Botanic Gardens, there are some tree species around here that are typical "early shedders" of their leaves in September, like Red Maples and Vine Maples -- probably a lot of what I was seeing.

What triggers the leaf color-changing process in those trees -- and eventually the other deciduous species -- is the increasing length of nighttime darkness in September and early October. The lack of sunlight messes with the photosynthesis process and it begins to breakdown, leaving the green colors to fade away and revealing the colors of other materials in the leaves. (If you want the really in-depth botanic explanation, check out this page by the United States National Arboretum.)

So that's why the time autumn leaves begin to change are pretty consistent for any region year-to-year, because the changes in length of day are the same every year, and why the seasons begin a little earlier in the north than the south because the length of days are getting shorter, quicker.

But it turns out weather can have a hand in both how brilliant a display is… and how long it lasts.

The perfect scenario for a lengthy, robust autumn leaves season is to have sunny, warm days, and cold nights -- but not too cold -- with little or no wind and ample soil moisture. According to the United States National Arboretum, cool nighttime temperatures combined with sunny days create more of the colorful materials inside the leaves, leading to a more brilliant display of color. But if it gets too cold and we get an early frost or freeze, it destroys the process, meaning an early end to the color generations and, in turn, an early end to the season.

Drought conditions like we've had around here tend to accelerate the decay process that keeps the leaves attached to the trees, making them fall earlier. Some at the UW think this may also be contributing to what seems like more leaves on the ground earlier this year around here -- the trees are feeling the stress of the drought and the leaves don't have as strong a bond to the trees. So while temperature-wise we've had good conditions to create colorful displays so far this September and early October, the dry weather will likely mean the trees will go bare sooner. (In other words, enjoy it while it lasts!)

Other factors that can spell an early end to the season would be stormy conditions. Usually the "stormy" season doesn't really get going in Western Washington until the third week in October -- which works well since that's past the typical peak of the fall colors anyway. But pelting raindrops and strong winds will knock the leaves off earlier too.

So summing it all up for what to expect in Western Washington for an autumn leaves season this October: With the generally sunny weather and cool overnight temperatures we've had this first week of October, we should have great colors, but the oveall dry weather means the season probably won't last as long as usual.

Stormier weather is in the forecast for the end of the week and weekend which could start knocking the leaves off -- more than it would in a normal rainfall year. However, extended forecasts are trending drier again for the middle of the month so whatever survives the weekend should look really good.

Watch: Northern Lights shimmer over Mt. Baker

Once again, our clear early autumn skies have come at a great time -- this time to catch another show of the Northern Lights across the Pacific Northwest.

Meg McDonald of Wild Northwest Beauty Photography just spent several days hiking around Mt. Baker and had her cameras at the ready when this dazzling display of the aurora peeked out Saturday night.

Mariners fans treated to near-record amount of sunshine this summer

Mariners fans treated to near-record amount of sunshine this summer
FILE -- The Seattle Mariners held their second annual “Bark at the Park,” which brought hundreds of dogs and their owners to the left field bleachers at Safeco Field on July 10th 2015. (Joshua Lewis / Seattle Refined)

Beachgoers and outdoor cafe connisours weren't the only people to benefit from the summer of sunshine this year. So did the Boys of Summer.

The super warm Seattle Summer of 2015 just narrowly missed setting a Safeco Field record for fewest number of times the roof has been extended in a season.

This year, just 11 of the Mariners' 81 home games have been played with the roof closed for all or part of the game, according to team spokesperson Rebecca Hale (5 games under the roof from the start; 6 closed duing the game.) The rains Friday night left it one short of matching 2006 and 2012 for the fewest closures in a year.

'Water year' rainfall nearly normal, so how are we in a drought?

'Water year' rainfall nearly normal, so how are we in a drought?
Teanaway River July 2015. On July 9th, the Teanaway River was flowing at 8 cfs. The normal range for this particular day is between 75-200 cfs. With flows this low, water temperature is also a major problem. The river gage at Red Bridge Road reported water temperature of 78.8 °F that day. (Photo and caption courtesy: Washington Department of Ecology.)

Happy start of the rainy season in Seattle! Sure, it's blazing sunshine of late again, but Oct. 1 is the official start and thus also marks the start/end point of the "water year."

In addition to tracking rainfall from Jan. 1 to Dec. 31, NOAA also tracks it from Oct. 1 to Sept. 30 (calling it the "water year" rainfall) since our rainy season goes from October to March, this way we can also get a good gauge of the autumn/winter as a whole and its impact on our water and snowpack situations.

For 2014-15, Seattle ended up with 36.82 inches of rain, just 2/3" below the normal of 37.49 inches.

But this year, it'd be real nice if "rainy season" lived up to its title, since our drought is still going stong.

Now some are probably wondering: "Wait a minute, but you just said we weren't that far below normal for our past 'water year', how can it be a drought?" Indeed, last year we had about 39.11" for our 2013-14 water year -- just a little more than 2" than this year -- and we weren't in this bad of shape.

Cool September breaks Seattle's 18-month heat streak

Cool September breaks Seattle's 18-month heat streak
Photo: Mirwais Azami Photography

Seattle's 18-month streak of consecutive months with above normal monthly temperatures has finally (mercifully?) come to an end.

September's average temperature was 60.5 degrees, coming in below our typical average temperature of 61.3 degrees. It's the first time we've been below normal for a month since Feb. 2014.

Supermoon plus eclipse equals rare sky show Sunday night

Supermoon plus eclipse equals rare sky show Sunday night
A lunar eclipse is seen on Saturday, April 4, 2015, in Placerville, Calif. (AP Photo/The Sacramento Bee, Randall Benton)

What happens when you combine a "Supermoon" with a total lunar eclipse this Sunday night?

Something that is even rarer than once in a blue moon!

When a full or new moon makes its closest approach to Earth, that's a supermoon. Although still about 220,000 miles away, this full moon will look bigger and brighter than usual. In fact, it will be the closest full moon of the year, about 30,000 miles closer than the average distance. (The moon's orbit is far from a perfect circle.)

Loud 'crazy birds' update: Blame Greater White-fronted geese?

Loud 'crazy birds' update: Blame Greater White-fronted geese?
Greater White-fronted geese. (Photo courtesy: North Dakota Game & Fish Department)

A mystery of what caused a very loud ruckus of birds over South King County Sunday night may be solved.

Reports flooded in across a wide swath of area ranging from about Puyallup's South Hill to Enumclaw of birds that sounded distressed, circling for hours.

Grant Canterbury, a biologist with the U.S. Fish and Wildlife Service in Portland says the noisy birds were Greater White-fronted geese, who were on their fall migration.

Seattle summer (mercifully?) ends after breaking or tying 28 records

Seattle summer (mercifully?) ends after breaking or tying 28 records
Seattle on a sunny Friday. (Photo: Tim Durkan)

Autumn officially began its reign in Seattle at 1:21 a.m. Wednesday and it was none too soon for those who don't have air conditioning and waded through the hottest summer on record.

Many records were shattered to lengths that records are rarely broken -- such as 12 days at or above 90 degrees this year, topping the old record by 33 percent!

Since when does autumn begin on Sept. 23?!?

Since when does autumn begin on Sept. 23?!?
Photo courtesy: Meg McDonald, Wild Northwest Beauty Photography

 Happy first day of autumn! Hey, wait, today's the 23rd, right?

I don't know about you, but growing up, I learned the seasons changed on the 21sts of their month, but it seems like that's rarely the case. Autumn began on Sept. 23 this year -- the same year that spring began on March 19.

It turns out, I don't know where we got Sept. 21 as a good date to teach us in school, because autumn hasn't started for real on the 21st in any of our lifetimes. The earliest start to autumn in the past 115 years is 7:50 a.m. (PDT) on Sept. 22 in 2012. To that effect, spring won't start on the 21st in most of our lifetimes either, unless you're super healthy (or perhaps reading this a grade school project) and live to the year 2102.

Photo puts massive Eastern Washington wildfires into perspective

Photo puts massive Eastern Washington wildfires into perspective
Photo: NASA/MODIS Satellite of Washington (false color) taken on Sept. 21, 2015, via National Weather Service in Spokane.

We already know it's been a record-setting wildfire season, with nearly 1 million acres burned across Eastern Washington.

The fires are mostly out now, but their burn marks remain.

Climbers create their own amazing shot of 'Brocken Spectre'

Climbers create their own amazing shot of 'Brocken Spectre'
Photo of "Brocken Spectre" atop Tramanos Mountain on Sept. 19, 2015 courtesy Radka Chapin.

It's not easy to create your own optical illusion, but mountain climbers and hikers who have ever been out and about on a sunny and foggy day did just that, creating what's known as a "Brocken spectre."

Radka Chapin and her husband got to see the amazing sight while they were up at Tamanos Mountain on Saturday.

"We got treated to a spectacular light show with Brocken Spectre," she said. "We spent several hours on the summit! We tried to leave several times but then the Spectre would start showing again and it was so magnificent, we had to stay and watch it. We ended up hiking out with headlamps :) "

What was with all the crazy birds in SE King County Sunday night?

It wasn't the reincarnation of an Alfred Hitchcock movie, but we got several reports of strange, loud bird behavior in Southeast King County Sunday night.

People emailed from Graham, Enumclaw, Bonney Lake and South Hill/Puyallup noting the bird commotion, asking us if we had any idea what was happening.

"Anyone know what's going on with the birds??" one person posted on a neighborhood Facebook post. "There have been a lot of them, and I do mean it sounds like a lot of them, over the last several hours. We've lived up here for 10 years, and never, until tonight, heard all this noise. They get quiet, then they start up again. At times they sound like they're in flight, but always close by."

New forecasts still say mild winter, hot summer again for Northwest

New forecasts still say mild winter, hot summer again for Northwest
Photo: Jason Shipley

Despite September looking like it will break our streak of 18 consecutive months with warmer than normal temperatures in Seattle (although not a guarantee yet), the newest 90-day forecast maps from NOAA's Climate Prediction Center are pretty adamant we'll start the streak anew in October.

And it's likely the new streak will get several months under its belt as well, as the maps still suggest high confidence we'll be warmer than normal through the winter. The confidence drops a little in spring and a little farther for summer 2016, but the odds given are still much better for more relative heat than relative chill.