April Showers Brought More May Showers

Don't be confused by the title of this blog...I know that the saying is "April showers bring May flowers" but this year, the April showers brought May flowers and May showers. Lots of May showers.

We are forecasting a week of showers. If you’re saddened by a lot of rain icons on your weather app, most days just have showers. Try counting how many times I say showers in this blog...

Expect partly cloudy-partly sunny weather for the next week. Showers will be likely on every day, except Friday the 15th, which will be sunny and 65-70 degrees! After that, steadier rain will move through the area at times from Saturday-Monday.

Some of the showers could be stronger, with possible heavy rain, gusty winds, and in a rare case hail and thunderstorms. I took this picture on Tuesday, showing a strong cell near Federal Way. 

This cell was pretty routine for this pattern, with some heavy rain under those dark clouds.

Enjoy the showers and sunbreaks, and know that an above average summer lays ahead, hopefully with lots of sun for us to enjoy! 😊

Also, I said showers 13 times including in this sentence and in the title 🌧🌧

Chance of Thunderstorms This Evening

Forecast models are showing increased instability this evening, particularly in the mountains and South Puget Sound area.

At this time, the greatest threat for thunderstorms is from 5-10 PM. The forecast model below shows the CAPE (convective available potential energy...or instability) at 7 PM. 

You will notice that the CAPE values in the South Sound are 400-950 j/kg. That’s pretty unstable for our area. 

Why is this happening on a sunny day? Because it’s sunny. Sunny weather allows for daytime heating which greatly increases instability. (We didn’t have enough daytime heating this weekend to support thunderstorms). 

Some cells have already began in the Cascades, with some lightning reported as well. Expect some to move into the lowlands as the evening goes on. 

As always, expect gusty winds, heavy rain, and possible hail and lightning in any showers that move through tonight. Rain returns tomorrow...but from Thursday to Monday it will be sunny and 70-85 degrees!!!!

Strong Cold Front, Chance of Thunderstorms This Weekend

Reflection: Posted on Monday 5/4

Due to plentiful clouds on Saturday, instability for thunderstorms failed to develop. The cold front on Saturday also moved slower than expected, making it harder for storms to form on the frontal boundary.

Sunday also failed to produce enough instability for thunderstorms. It was a hit-or-miss day in terms of rain showers.

Sunny and 75-80 likely at the end of the week...stay tuned!!

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Showers are moving in to Puget Sound as part of a warm front begin to come in off the coast. However, Saturday is when the weather gets interesting. Let's examine it...

Stage One: Pre-frontal Showers

Before the front moves through, showers will be present in the area, along with instability in the atmosphere. Around 5 AM tomorrow, showers will start to increase. Inside these showers will be heavy rain, gusty winds, and possible hail & lightning.

I would expect these showers to continue until around noon on Saturday.

Stage Two: Cold Front With Embedded Thunderstorms

Around 1 PM tomorrow, an unseasonably strong cold front will move through Western Washington. This forecast model shows the simulated radar at 2 PM Saturday. 

I made a pink line that shows the back of the cold front and what approximate direction it is moving. You will notice that the rain inside this front is heavy at times. 

As the front is moving through Western Washington, the air will be unstable. The model below (also for 2 PM Saturday) shows instability, or CAPE (Convective Available Potential Energy).

It is very interesting that at the same time that the front is moving through Western Washington, there is an area of increased instability. The CAPE values in the front are 200-300 j/kg. Winds will also gust 20-30 mph during the frontal passage, with higher gusts possible.

Those values are enough to cause thunderstorms in Western Washington. Please be prepared for heavy rain, strong winds, lightning strikes, and hail. 

There is a potential for stronger-than-normal thunderstorms, and there is a marginal risk of sever thunderstorms in parts of the Pacific Northwest tomorrow. Take a look at this map below from NOAA's Storm Prediction Center.

Notice the darker shade of green over parts of Oregon and Eastern Washington. That means an increased risk of severe thunderstorms (damaging winds, severe hail, heavy rain, very low tornado possibility).

There is a chance that a stray strong thunderstorm will make its way in to Western Washington. That's why we should always be prepared!

Stage Three: Sunday Thunderstorms

After the front moves through on Saturday, instability will remain. At this time, the highest chance of thunderstorms will be from 11 AM to 10 PM on Sunday. Additionally, there is a higher chance for storms from 5-10 PM. 

This entire weather sequence will drop 0.7-1.1 inches of rain. 

Remember to be prepared for thunderstorms, hail, gusty winds, and heavy rain.