Warming Up Over The Weekend!

Good afternoon everybody!

If the transition to autumn has sent your psyche to rock bottom, I bring good news that could help cure your blues. Summer will make a brief return on Sunday and stick around through early next week!

We’ve got a weak frontal system to get through first, but those are good too, as it will quench the ground’s thirst, and return our grass to a deep green hue. And come Sunday, our skies will turn a brilliant blue.

Ok, enough with the sappy rhymes. Let’s get scientific.

Valid 05:00 pm PDT, Thu 22 Sep 2016 - 12hr FcstCredit: University of Washington Atmospheric Sciences
Valid 05:00 pm PDT, Thu 22 Sep 2016 – 12hr Fcst
Credit: University of Washington Atmospheric Sciences

Here’s the current 500mb absolute vorticity chart, one of my favorites. As you can see, there’s a deep trough digging off the West Coast. It is currently spinning some moisture throughout the Intermountain West, but Seattle and Portland have stayed dry today. As the above chart shows, we have a weak ridge offshore that has helped bring sunny skies to the area, but a cold front is approaching from the west. It is hard to discern it in the chart above, so take a look at the chart below, which shows temperatures around 2,500 feet up, surface wind, and sea-level-pressure.

A ridge is off the coast, but a front is approaching. The "V" in the isobars (lines of constant sea-level-pressure) shows the front, with pressures falling ahead of it and rising behind itValid 05:00 pm PDT, Thu 22 Sep 2016 - 12hr Fcst
A ridge is off the coast, but a front is approaching. The “V” in the isobars (lines of constant sea-level-pressure) shows the front, with pressures falling ahead of it and rising behind it
Valid 05:00 pm PDT, Thu 22 Sep 2016 – 12hr Fcst
Credit: University of Washington Atmospheric Sciences

September fronts in the Pacific Northwest are some of the most pathetically anemic fronts you’ll find anywhere in the world, and though this front isn’t the wimpiest I’ve ever seen, it’s far less juicy and vigorous than the fronts we’ll see when November rolls around. However, the coast still stands to get a solid dose of rain and some gusty southerly winds Friday morning. The front will be torn up by the Olympics as it makes landfall, and as a result, the Seattle metropolitan area will only see light rain around noon Friday, with little in the way of wind.

Valid 08:00 am PDT, Fri 23 Sep 2016 - 27hr FcstCredit: University of Washington Atmospheric Sciences
Valid 08:00 am PDT, Fri 23 Sep 2016 – 27hr Fcst
Credit: University of Washington Atmospheric Sciences
Valid 05:00 am PDT, Sat 24 Sep 2016 - 48 FcstCredit: University of Washington Atmospheric Sciences
Valid 05:00 am PDT, Sat 24 Sep 2016 – 48 Fcst
Credit: University of Washington Atmospheric Sciences

After this front comes through, a ridge builds in and a weak thermal trough tries to extend northward into Western Washington from California, drying us out, calming us down, and clearing us up. Expect improving conditions on Saturday and sunny skies Sunday and Monday with highs skyrocketing to the mid-upper 70s throughout Western Washington, perhaps even hitting 80 in places on Monday. No, we aren’t witnessing the 90 degree temps we saw a month ago, but I don’t think most people are complaining.

Valid 11:00 pm PDT, Sun 25 Sep 2016 - 90 FcstCredit: University of Washington Atmospheric Sciences
Valid 11:00 pm PDT, Sun 25 Sep 2016 – 90 Fcst
Credit: University of Washington Atmospheric Sciences

Enjoy the sunshine!

Charlie

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