Wednesday, July 18, 2012

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.


Wednesday, July 4, 2012

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.