Bye Bye Dry Streak

Saturday, September 8, 2012
9:07 P.M.

As I write this blog, I'm listening to Miles Davis' and John Coltrane's famous rendition of "Bye Bye Blackbird." It's a wonderful song, but as I listen to Miles' soulful tone, I can't help but feel a bittersweet sentiment in my soul. Because for me, the "Blackbird" is not only this dry streak, but this summer mindset in general. It's time to say goodbye to the lazy, long days of summer and it's time to think about school. I have to say though, I'm definitely looking forward to my sophomore year at the University of Washington and the experience of surrounding yourself with a seemingly unlimited supply of wonderful people, enlightening schoolwork, and drugs/sex/rock&roll. Just kidding about that last one. Kinda ;).

But in all seriousness, this front symbolizes summer's departure and autumn's arrival. It's Mother Nature's way of refreshing our minds and helping prepare us for the changes we will all experience as the nights become longer, the leaves become redder, the temperatures become cooler, and the days become rainier.

What's responsible for ending such a long dry spell? Let's look at some satellite photos to find out! I'm gonna go back in time a little for you, so you can see how the front that will bring us the first rain we have had in 48 days has come about.

03:30 pm PDT Fri 07 Sep 2012 - Eastern Pacific Infrared Satellite

The temperature at Sea-Tac Airport reached 90 degrees on Friday, which was the first time it has done so in 22 years. If you look at the satellite photo above, you can see a HUGE ridge of high pressure over the area with clear skies over all of Washington and much of the Pacific Northwest.

Today, the temperature only reached 77 degrees. Why?

09:30 am PDT Sat 08 Sep 2012 - Eastern Pacific Infrared Satellite

It's tough to make out, but there are some high clouds over the Pacific Northwest, and the flow transitioned from strongly offshore to slightly onshore. Our once strong ridge weakened considerably today.

Take a look at the latest satellite picture. The ridge has broken down even more, but more importantly, look at the Gulf of Alaska, and look at the center of low pressure that is beginning to form there. This, my friends, is the low pressure system that will give us the first rains we have seen in a very long time.

09:30 pm PDT Sat 08 Sep 2012 - Eastern Pacific Infrared Satellite

Obviously, you can't take satellite pictures in the future, but we do have a wonderful assortment of weather models that can do just that. Let's see what my favorite one, the UW WRF-GFS, says what the ultimate fate of this low pressure system will be.

Valid 11:00 pm PDT Sat, 08 Sep 2012 - 6hr Fcst - UW 36km WRF-GFS 3 hour precip

As of right now, there is a weak area of low pressure and some associated precipitation stretching from the Gulf of Alaska to the Queen Charlotte Islands.

But take a look at what is expected to happen a mere 12 hours later.

Valid 11:00 am PDT Sun, 09 Sep 2012 - 18hr Fcst - UW 36km WRF-GFS 3 hour precip

See that front? That's what's gonna bring the demise of our dry spell.

Here's a higher resolution model picture that shows you the 24-hour precipitation expected over our area from Sunday evening to Monday evening as the front brushes Washington.

Valid 05:00 pm PDT Mon, 10 Sep 2012 - 48hr Fcst - UW 4km WRF-GFS 24 hour precip

You can see that there is a little bit of precipitation over the Sea-Tac airport, and much more to the north, where a convergence zone is expected to form.

And, our dry spell will end.

Or will it?

Sorry, I couldn't help myself. :)

Charlie

It's Been 50 Days...

Thursday, September 6, 2012
10:24 P.M.

... since my last blog post.

Summer kind of does that to you. The more free time you have, the less you feel like doing. I've actually been quite busy with music and jobs, but that is no excuse for being off this blog for 50 days.

However, I do have one valid excuse, and that is that the Seattle-Tacoma International Airport has not seen any measurable rain in 46 days.

It's been boring, to say the least.

But as this dry spell has become longer and longer, my outlook on weather, and life in general, has changed.

Here's why. A 46-day long dry streak in Seattle is practically unheard of. There was a 51-day long dry streak in Seattle in 1951. I'd love to set a new record. Can we make it five more days?

Let's take a day-by-day precipitation analysis of the latest WRF-GFS UW model run to find out.

Some of the charts on that site are pretty tricky to read, but this one is pretty simple. Where there are colors, precipitation is expected to fall, and different colors respond to different amounts of precipitation.

Will we get to day 47?

Valid 05:00 pm PDT Fri, 07 Sep 2012 - 24hr Fcst - UW 12km 00z WRF-GFS 24 hour precip

Absolutely. Not a color to be found.

How about day 48?

Valid 05:00 pm PDT Sat, 08 Sep 2012 - 48hr Fcst - UW 12km 00z WRF-GFS 24 hour precip

Still clear over Seattle! But things start to get a little interesting on day 49.

Valid 05:00 pm PDT Sun, 09 Sep 2012 - 72hr Fcst - UW 12km 00z WRF-GFS 24 hour precip

Oh noes! The precipitation is infiltrating the Pacific Northwest. Seattle looks to stay dry for another day. Will the streak make it to 50?

Valid 05:00 pm PDT Mon, 10 Sep 2012 - 96hr Fcst - UW 12km 00z WRF-GFS 24 hour precip

The answer, in case you have poor eyes, is no. But there is hope! Weather models are not perfect, and there is a chance we could escape unscathed. I've never wished so hard for a dry day in my life.

Regardless of whether the streak gets broken, we look to be bone-dry for the foreseeable future. So go do something wet. Jump in the lake. Drink some orange juice. Make a slip-n-slide. But most of all, to all my friends and family, enjoy the rest of your summer. Because come November, there will be a lot more color on these maps.

Charlie

If You Can Hear Thunder, Does That Mean There is Lightning?

Friends say the darndest things...

I don't have the same "drive" to update my blog in the summer as I do in the winter. You've probably noticed. But folks, this last week has been pretty amazing. I can't recall ever seeing a week with as much thunderstorms in the lowlands as this one. And while our Oklahoman summer transplants may scoff at a Pacific Northwest "thunderstorm," I'm still glad they've been around. They add a little excitement to the otherwise humdrum summers of the Pacific Northwest.

What's been causing all these thunderstorms? Well, I'm not the greatest person to ask. They don't occur very often here and I don't know much about them. But what I do know is that from late Thursday to early Saturday, we had a very tight upper level low pressure center essentially stall over our area, and it provided moisture and lift. With moisture and lift, you get convection, and convection creates thunderstorms.

Valid 02:00 pm PDT Fri, 13 Jul 2012 - 9hr Fcst - UW 12z 12km WRF-GFS 500mb absolute vorticity, heights (initialized 5 A.M. Friday the 13th)

It seems like we often get thunderstorms with this type of scenario. We get these low pressure centers that direct warm, humid southerly air off the cascades and allow thunderstorms to travel from the Cascades down into the lowlands. That's right, our weather often comes from the EAST in these scenarios. Definitely a thing to delve deeper into.

The weather for the future? Kinda boring. :/

But if you hear thunder, you can bet your buttons that lightning isn't too far away.

Charlie

Summer Starts July 5th

Wednesday, July 4, 2012

12:06 A.M.

Us meteorologists like to joke that summer starts on July 5th. Well this year, that actually looks like it will be the case. Independence Day won't be bad at all. We'll start off with some clouds in the morning but quickly warm up to around 70 or so. The normal high for this time of year is 74.

And then, right on cue, July 5th rolls around, and we are forecast to hit 74. I think we might squeak out an extra degree, which would put us above average. And we don't just get above average and then fall below it again. We stay above average for as far as the model can forecast.

Valid 05:00 pm PDT Wed, 04 Jul 2012 - 24hr Fcst - UW 00z 36km WRF-GFS 1000-500mb thickness, SLP

Right now, we have a very weak jet stream over us, and this will further weaken throughout tomorrow and eventually cease to exist by Thursday night. After that, the jet stream will shift northward. The model above shows the 1000-500mb thickness. Where the thickness is higher, the temperatures are generally warmer. The temperatures get hot when you go inland!

But as the week progresses, we will warm up even further!

Valid 05:00 pm PDT Tue, 10 Jul 2012 - 168hr Fcst - UW 00z 36km WRF-GFS 1000-500mb thickness, SLP

Look at that! Warm temperatures up and down the Best Coast. Next week will be a great time to go swimming in Lake Washington.

Thanks,

Charlie

Back From The Dead!

My, my my! It certainly has been a long time. Well, I could enamor you with excuses, but I'm not here to justify my actions (or lack thereof).

I'm here to predict the weather.

To say that June has been rather chilly is an understatement. To quote Scott Sistek of KOMO, "Today marked the 20th time in June's first 25 days where temperatures stayed below average." Yeah. It's been pretty bad.


The last several Junes have been pretty darn chilly, and many have dubbed them as "June-uary" because of their unseasonable coolness. This is likely because of La Nina. Although La Nina is dead now, its effects tend to lag on well after the Pacific warms past the La Nina phase. I was down in Portland over the weekend visiting my uncle and a dear friend, and it was pretty wet there. I heard it was even wetter up here in Seattle.

... until we see some summer? Well, if trends are correct, we will start to see summer on July 5th. But the current forecast has a different outlook. It calls for a damp Tuesday, a wet Thursday, and a soaking Saturday, but Wednesday should be nice, Friday should be decent, and once we get into next week, it's cloudy mornings and sunny afternoons as far as the mind can grasp. Perfect summertime weather.

Ahhhhhhhhhh... it feels good to be back on the blog again. Thanks for reading. :)

Charlie