All posts by Matthew Leach

Winter Outlook 2013-2014: Another “wild card” year

Christmas Day Snow, 2012 in Seabeck. Photo by Don Geidel
Christmas Day Snow, 2012 in Seabeck. Photo by Don Geidel

Alright, I have put this off long enough! Time to do my yearly ritual of witchcraft–erm, I mean, long range forecasting.

Let’s make this clear from the beginning: There are many variables to consider when making a forecast that extends months into the future; weather forecasters struggle enough to get tomorrow’s forecast right. Among the most popular ways to determine long term trends are ocean temperatures, which can play a significant role in what kinds of land temperatures and precipitation will be most prominent during a given season.

At the present, the north Pacific Ocean is in a cold phase, which has correlated to cooler, more active weather for the West in the past, but isn’t necessarily a determining factor.

In addition, the equatorial Pacific can give us an even clearer look into general seasonal weather patterns, from the development of an El Nino event, which leads to warmer and drier conditions for the Pacific Northwest, or a La Nina pattern, which brings colder and wetter weather. Unfortunately, neither of those patterns will be able to help in this year’s forecast because we are witnessing the rise of what is unofficially known as La Nada. That’s right: no warm signals and certainly no cold signals. It’s no wonder meteorologist call this pattern a “wild card”.


Let’s revisit what analogs are and why they might be useful in constructing a forecast.

Analogs are past years that exhibit some similar weather activity to the current year, and as a result weather forecasters try to match up the past with the present to see if there’s some type of correlation or pattern occurring. More often than not it’s just a guide, but sometimes history does repeat itself.

Other reliable pieces of data essential for producing a long range forecast is the ONI, or Oceanic Nino Index to track what El Nino, La Nina or neutral years in the past match up similarly to the present day. The records I have go all the way back to 1950. Solar activity can be another major factor to the weather over the years, but I haven’t weighted that heavily enough in my forecast mainly because of the lack of data. Lastly, I used the PDO readings (Pacific Decadal Oscillation) to finalize my findings.

Here are some of the top corresponding years:

2012 (interestingly enough)



If any of you remember the winters of 2012-2013, 1990-1991 or 1978-1979, you will recall that there’s a healthy mix of benign weather  (dry, mild, no snow) and awesome weather (arctic intrusions, buckets of snow). As it so happens, that’s probably the best description of what to expect this winter.

Screen Shot 2013-11-16 at 3.11.46 PM


Screen Shot 2013-11-16 at 3.12.04 PM


There are some strong signals indicating December will, once again, provide us with some of the best opportunities for some chilly weather, but perhaps not the most ideal for snow. The reemergence of a pretty healthy ridge will limit the amount of precipitation we receive, but not for long. After a generally pleasant beginning to the month, there are signs that the jet stream will gradually begin to sag south and west, bringing in a decent shot of cold and moist weather. Could this result in a repeat of last years white Christmas event? The chances are, of course, very low, but it looks like we could at least be heading in the right direction. Temperatures will average a couple degrees below normal with precipitation right around average, if not a little below.


January, as a whole, looks downright chilly for most of the country, with very little in the way of temperature fluctuations. An active jet stream and negative PNA (Pacific/North American teleconnection pattern) should also increase the mount of storminess on the West Coast with plenty of mountain snow and several shots at lowland snow. This doesn’t look like a pattern conducive to too many “Pineapple Express” systems, however, so precipitation likely won’t exceed average by much if at all. The coldest and stormiest periods will be between the 1st and the 15th with a gradual change for the drier by the end of the month.


February, as has been typical in the Northwest for quite some time, will be drier than normal, but this time with a twist: It also looks a bit chillier than normal. This will be primarily due to cold overnight low temperatures, as most daytime temperatures should average at or slightly above normal. The most active weather will be found further east as the PNA shifts to a positive phase and the North Atlantic Oscillation, or NAO, takes a plunge. However, it looks like we could run into a few “overrunning” events along the Hood Canal as we switch to some milder weather towards the end of the month.

MARCH 2014

After a chilly start, we’ll likely see fairly tranquil conditions be the dominant feature through March with below normal precipitation. In fact, we could see some record high temperatures towards the end of the month.

So there you have it! A pretty cold and active beginning to winter with a gradual change to milder and drier weather. We’ll check back in once spring rolls around to see how I did.

Have a great weekend, and stay warm!

Matthew Leach

Forecasting Kitsap

Questions? Comments? Photos? E-mail Matt Leach at:


Why do leaves change color in the fall?

The chilly nights and mild days of late have helped accelerate the process by which leaves change their color. Peak times to view fall foliage differ all across the country, but we still have a few more weeks before the great Northwest’s colorful show of reds, oranges and yellows vanish for another year.

But this begs the question: What causes leaves to change color in the first place?

Photo by flickr user: ForestWander
Photo by flickr user: ForestWander

Between late August and early October, many people all across the United States and Canada willingly travel hundreds of miles to witness one of Mother Nature’s most beautiful pieces of artwork: fall foliage. A most breathtaking natural spectacle, the wild splashes of red, orange, brown and yellow leaves racing up and down rolling hills and lining quaint neighborhoods brings a certain homey nostalgia with it. However, some places seem to have a tendency to produce this natural artwork more flamboyantly than others, and there’s a good reason for it.

Those green leaves that we often run to for protection on hot summer days contain what is called chlorophyll. There is so much of this pigment within the leaves that it masks the others. Sunlight is one of the biggest factors in providing chlorophyll, so naturally summertime is when green leaves thrive. However, as light diminishes come autumn, so does the chlorophyll. This finally allows the other natural pigments, called carotenoids, to steal the show. They come in yellow, brown, orange and a variety of hues in between.

Photo by flickr user: Christopher Penn
Photo by flickr user: Christopher Penn

There are some colors, however, that appear on leaves that weren’t there before, and these are called anthocyanin pigments. These red and orange colors form due to an increase in sugar concentration in plants, typically occurring towards the end of summer. The more anthocyanins present, the more burning reds you’ll see on your next fall foliage trip.

Colder, northern climates tend to accelerate the process of chlorophyll decomposition. For instance, St. Paul, Minnesota would see fall foliage peak around late September, but Tulsa, Oklahoma would likely see it peak in early November. This shows that temperature does effect leaf coloration to some degree, but it is not the determining factor. The sunnier the autumn days, the brighter the “new” colors.

If autumn welcomes us with plenty of autumn sunshine with cool, crisp nights next year, expect a dazzling show.  On the other hand, if the clouds just won’t quit and the air remains a bit on the mild side, expect a more conservative presentation of duller yellows and browns.

Grab your umbrellas, and maybe your snorkels, too. It’s going to get wet around here!

Go figure! Western Washington is going to get wet. But let’s be clear about what weather models are advertising for this weekend: It’s not going to be a typically drippy late September weather pattern. A series of fronts will actually move their way through Western Washington that could pack enough of a punch to take care of July, August and September’s rain totals combined.

Here’s a look at what I’m seeing by 5pm Friday evening:

Screen Shot 2013-09-26 at 6.45.46 PM

Seems innocent enough, right? About a quarter inch of rain for the main Kitsap area with places to the south or north receiving a bit more. What’s the big deal? Well, here’s Saturday’s system (totals ending at 5am Sunday):

Screen Shot 2013-09-26 at 6.46.10 PM

I don’t know about you, but the western part of this map looks like a big, nasty bruise. And I suppose in some ways it could be considered such. Rainfall totals by early Sunday morning could amount to as much as 2.50″ for Kitsap County. Incredible! But let’s take a step back and look at this sucker from a 72-hour point of view (totals from Friday through Sunday PM):

Screen Shot 2013-09-26 at 6.46.45 PM

I was about to put a “Viewer Discretion is Advised” label on this picture because of its graphic content. In 72-hours, the University of Washington’s Atmospheric Sciences models place us anywhere between…*gulp*…2.50″ to 4.50″. I don’t know of any other way to say it: This weekend will be an absolute washout. A soaker.

Ok, now that you know the precipitation stats, why is this happening to us? What has innocent Western Washington done to deserve this deluge of rain in such a short amount of time? Friday’s system is really nothing impressive, but Saturday’s storm will have remnants from an old typhoon that will help boost the precip totals. So basically, wave after wave of what would normally be a typical rainy Washington weekend is being enhanced by more moist influences.

Stay tuned for some possible Flood Watches or Flood Warnings. I wouldn’t be surprised if they were posted in the coming days.

Once the storm passes Sunday night though, the snow level really plummets. By Monday the snow level will be at around 5,000′ with temperatures barely reaching the upper 50s.

So stock up on the umbrellas! We might think we’re used to rain, but this kind of rain doesn’t come around very often…

Have a safe weekend,

Matthew Leach

Forecasting Kitsap

Questions? Comments? Photos? E-mail me at:

We’ve reached that (coveted? blessed? cursed?) milestone of 90º in September…


First of all, sorry for the black text on the light blue background. Is it bothering all of you as much as it’s bothering me? I can’t tell you how many times I’ve tried to change it to white.

ANYWAY, we did it. Since 2:30 pm we’ve been sitting at a solid 90º. It’s about 3:30 pm right now and I’m confident we’ll be able to squeeze out a few more degrees before this early September heat spell winds down. This means our record high temperature of 86º set back in 2011 is…well, a thing of history.

We still have a couple more days of unseasonable warmth as offshore winds and a late-season thermal trough slowly fizzle away. Thursday and Friday both look mostly sunny with highs in the low to mid 80s. For those just itching for more fall-like weather, true relief arrives by the weekend with highs settling down into the low to mid 70s.

Have a great day!

Matthew Leach

Forecasting Kitsap

Questions? Comments? Photos? E-mail me at:

Early September heatwave on the way


In this morning’s weather discussion on the Kitsap Sun’s homepage, I discussed the possibility for a pretty major heatwave to take place midweek this week. Not that I advocate playing hooky, but…well, if there was anytime to take a few days off of work or school to enjoy summer’s last hoorah, it would be Wednesday and Thursday of this week. Heck, let’s just add in Friday for good measure 😉

A building thermal trough from the south is getting ready to pump in some heat for Western Washington from the already heat-opressed regions of the Desert Southwest (read more about thermal trough’s here). This will spell a series of sunny and hot early September days with clear nights. In fact, we could have some of the warmest temperature readings of the season over the next few days.

Here is a temperature forecast brought to you by the University of Washington’s Atmospheric Sciences department. The following map shows Wednesday’s high temperatures. As you can see, most of Kitsap County is well into the 80s, if not near 90 degrees for some spots:

Screen Shot 2013-09-10 at 10.29.25 AM

And here’s a peek into Friday, which shows us “plummeting” to near 80 degrees:

Screen Shot 2013-09-10 at 10.32.08 AM

Reaching 80 degrees in September has actually become quite the norm around here in recent years, but reaching 90 is nothing short of a late summer miracle. Here are some years we got close to or exceeded 90 degrees in the past decade:

  • September 11th, 2011: 86 degrees
  • September 22nd, 2009: 93 degrees (I should also add we dipped down to a jaw-dropping 46 degrees that night!)
  • September 10th, 11th 2007: 84 degrees
  • September 3rd, 2006: 95 degrees (also an overnight low of 46!)
  • September 28th, 2003: 86 degrees

Another interesting note: We have managed to exceed 90 degrees twice in the past decade, while every year before that going back to the early 90s we hardly ever got close. To compliment that, particularly warm Septembers have almost always correlated with a sharply colder and wetter fall season. Why? I’m not sure, but the correlation is there!

How about breaking records? That’s tough to say around here, since record keeping is spotty in the Kitsap area, but the records I have indicate today (September 10th) holds a record high of 84 degrees set back in 2007, September 11th’s record is 86 degrees set back in 2011, and September 12th’s record is 82 set back in 2002. I think we have a decent shot at breaking all of those records!

So yes, it’s going to get exceedingly warm around these parts over the next couple of days. But fear not, cool weather lovers! Our natural air conditioning kicks in by the weekend into early next week, bringing temperatures back to the low to mid 70s. Weather conditions beyond that get a little fuzzy to pin down, but it does appear this is summer’s last gasp.


Matthew Leach

Forecasting Kitsap

Questions? Comments? Photos? E-mail me at:


September making it a goal to outdo August storms


Rain Storm

Photo by YouNews contributer CadenceWhittle, Mukilteo, WA (8/29/2013)

The above picture is probably all that is needed to conjure up memories of a stormy late August evening. Then again, this turbulent event wasn’t all that long ago. In fact, tomorrow (Thursday) marks the one week anniversary of this rare August weather pattern, and we’re about to go another round of heavy rain and storms because…well…Mother Nature says so.

First of all, a FLOOD WATCH is in effect from 12:00 pm September 5th through 6:00 pm September 6th  for the Puget Sound region including Kitsap County. This watch has been issued because, according to the National Weather Service,


Is it just me, or does it sound weird to say this is our second major storm of the summer season? We hardly ever have a first!

Let’s take a look at this bad boy on the satellite picture. Notice the tight spin just off the coast:


That clearly defined low pressure system will slowly track eastward through Oregon and then creep northward toward our area. This won’t be the kind of tightly-wound low pressure system that produces extreme wind, but it will produce some pretty hefty rain totals (hence the Flood Watch):


The above image, which comes via the University of Washington’s plethora of weather models, advertises about an inch or more of rain for much of Western Washington (green/pink colors), with most of the coast experiencing lighter totals in the 0.30-0.70″ range.

Also, if we take a look at the CAPE (Convective Available Potential Energy), it is exceptionally high for our region (the brighter the shade, the more instability)


Therefore, expect not only periods of heavy rain Thursday into Friday morning, but also a series of thunderstorms. Of course, startling thunder, blinding lightning and copious amounts of rain in a short amount of time come in the “thunderstorm package deal.”

So there you have it! It’s going to be a wet and stormy 48 hours, so be prepared for areas of flooding and unfavorable traffic conditions.

Be safe out there! More updates as they come…

Matthew Leach

Forecasting Kitsap

Questions? Comments? Photos? E-mail me at:

Stormy August skies continue into the weekend

Image by YouNews user ahudda
Seattle Lightning. Image by YouNews user ahudda

What a show last night! Reports from all across the peninsula revealed lightning was extensive and thunder was often loud enough to shake windows and wake many out of a deep sleep. We even had a bit of rain and hail last night, and some areas reported increasing wind. But the turbulent skies of August haven’t finished their show. No, if anything, Mother Nature is going to pick up where she left off.

That spinning area of low pressure is already kicking up some moisture that will serve to fuel the atmosphere with more instability. Depending on the amount of sunshine we receive this afternoon, we could be looking at another very impressive show. Here’s an excerpt from the most recent discussion by the Seattle NWS:


So we have a couple more days left to dodge the strikes and the wind. Just be extremely careful with your outdoor activities. If you hear or see a storm approaching, take cover. But if you’re taking cover and happen to remember to take and send some cool storm photos, I would be most grateful 🙂

Have a wonderful weekend!

Matthew Leach

Forecasting Kitsap

Questions? Comments? Cool storm photos? E-mail me at: