Cliff Mass Weather Blog (2024)

It is a phrase that puts fear into the hearts of all true Northwesterners: June Gloom.

You thought we escaped it? Think again.

But first, we have an even warmer day than today in store for Saturday, with Puget Sound Country hitting 80F and another ten degrees over the Columbia Basin.

During June Gloom periods the northeastern Pacific fills with low clouds, which push into western Washington and Oregon (see below). In fact, the whole West Coast can suffer from this affliction.

The cloud coverage this morning shows why today was so warm:

But Sunday morning is a different (and cloudier) story.

As is Tuesday (below)...and Wednesday and Thursday.... is the same. That is June Gloom!

The high-resolution MODIS satellite image taken mid-day yesterday was remarkable, with extensive wave-like cloud features east of the Cascade crest in Washington and Oregon (see below). More waves over Montana as well.

Here is a closer look at the waves over eastern Oregon. Very regular features with north-south cloud lines and clear zones between them.

A combination of heavy rain and wind, more reminiscent of November than June, came through yesterday and this morning, and the effects were substantial.

Winds gusting to 35-50 mph, acting on fully leafed out trees, led to massive loss of branches and trees. My bicycle commute to the UW along the tree-lines Burke-Gilman trail was interrupted by several major treefalls (see picture below).

Tens of thousands of Seattle City Light customers lost power this morning. Same for Puget Sound Energy.

Below is a plot of maximum winds overnight. Some mountain locations gusted over 60 mph, with over 45 mph near Puget Sound, the Strait, and the Washington coast.

Why were the winds so strong?

The figure below shows the sea level pressure (solid lines) at 8 AM this morning. A Pacific low-pressure system passed north of western Washington, creating a large north-south pressure difference that accelerated the winds northward.

Precipitation totals? Over the past 36 h (see below), the western slopes of the Cascades and Coastal Mountain received 2-4.5 inches.... a lot for June.

Puget Sound was rainshadowed by the Olympics and Seattle "only" received about 1 inch.

If you really want world-class mountain rainshadowing, head to a station just south of Port Townsend, which only received 0.11 inches over the same period (see red arrow). No wonder folks retire there.

Western Washington and Oregon rivers are running very high now, some at record levels (see below, blue and black dots are much, much higher than normal).

I hope the Drought Monitor folks will consider dropping the "moderate drought" designation for the western Cascades slopes.

More showers are occurring today across the region, as shown by the latest radar image (see below)

Enjoy this wet interlude. Drier conditions and a slow warm-up are expected Wednesday through Saturday, as our highs climb into the mid-70s.

Mother Nature is keeping the meteorological plate full for us.

My new podcast describes the latest on heavy rain events occurring on Sunday through Tuesday. But we are now close enough in time to see what's next: a minor heatwave peaking over next weekend, with the potential for thunderstorms from the Cascade crest eastward.

Friday afternoon, the European Center model has thunderstorms over eastern Washington

The simulated radar imagery from 11 PM next Saturday from the UW WRF model shows an area of thunderstorms moving into western Washington.

You can listen to the podcast below or through your favorite podcast server.

We are about to begin a historic rain event, with the one or two-day rainfall being in the top five of the historical record over Puget Sound. Some other locations we do even better.

Impressively, the Snoqualmie River is predicted to flood with record-breaking flows for any day in late May or the first half of June.

The rain will start mid-day on Sunday and it will go on for several days.

Let's start with the predicted total precipitation through Tuesday morning (below). Just wow...much of our mountain areas will receive over 3 inches, with limited areas getting over 5 inches.

An extraordinarily intense atmospheric river, one quite rare for early June, will slam into the region. The water vapor transport map for Sunday afternoon illustrates this (see below). This would be impressive in November. In June, startling.

Shockingly, this plume of moisture can be traced all the way back to southeast Asia!! (see map below for the same time). Another Chinese import (😃).

The sustained heavy rain is predicted to take the Snoqualmie River to flood stage--and the highest level ever observed this time of the year (see plot below from the NOAA/NWS Portland River Forecast Center). The orange line shows flood level and the upturned red arrows show the highest historical levels for each day.

How unusual is the event?

Below are the top ten precipitation values for SeaTac for the first half of June. The current predicted two-day total at that location is about 1.5 inches, so could enjoy the third or fourth wettest totals since 1945,

Keep dry!

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Announcements

I will be doing a podcast about the event later today.

I will be teaching ATMS 101 this fall--the introductory atmospheric sciences class.

The class will be BOTH in person at the UW and available over Zoom. Thus, folks can take it remotely.

If you are over 60, you can take the class through theACCESS programfor a very nominal charge (something like $20). During the past few years, several hundred have done so.

So if you are a UW student looking to learn about weather or a non-student interested in the topic, I welcome you to join me this fall.

An extraordinarily heavy precipitation event for early June will occur next week, with daily rainfall records falling and many regional rivers hitting record levels for June.

Rain so heavy that the wildfire threat will be greatly diminished for an extended period and regional reservoirs will get a mighty "top off" before our normally dry summer season.

Let me show you the latest forecasts, and be prepared to be amazed by the soggy bounty ahead.

Consider the latest European Center accumulated precipitation forecast for their model run starting 5 AM this morning (below).

The total through 5 PM today (Wednesday) is wet enough, particularly on the western side of Cascades where as much as an inch should fall.

With more showers on Saturday, the totals become more substantial over Northwest Washington.

But you haven't seen anything yet. A very moist atmospheric river comes in on Sunday/early Monday and precipitation totals go crazy, with 2-4 inches on the western slopes of the regional mountains.

The totals by Wednesday morning are staggering, with some favored locations getting to 4-6 inches of rain. This is unusual for June, to put in mildly.

After the turbulence encounter by a Singapore Airlines aircraft, there has been a slew of articles claiming that severe turbulence incidents are rapidly increasing due to global warming. The articles below in the Seattle Times and on the BBC are just two of hundreds of such stories

Several stories have been quite specific stating that turbulence has increased 55% in 50 years, based on a study by investigators at the University of Reading.

The media did not tell you that the increase was so minor. Still worried? And that paper said nothing about the other sources of strong turbulence, which in total are more important than the shear-induced, clear-air turbulence they considered.

And there are other technical problems with the above paper that could be a real problem. For example, the weather observational system has been greatly expanded and enhanced over the past 40 years, allowing observations to far better define atmospheric structures that can produce turbulence. Massive additions of satellite data and aircraft observations have occurred during the period in which the Reading group claimed the threat was increasing the most. Was the threat really increasing or was our ability to define strong wind shear layers getting better. They didn't say.

In summary, I believe there are no reliable studies that indicate a substantial increase in aircraft turbulence due to changing climate conditions. The media is needlessly causing folks to worry about flying.