Wetand News

 One of the advantages of residing in the northern portion of the U.S. is that occasionally we can view an aurora. And a beautiful one occurred last night, shown dramatically by the cameras at Greg Johnson's Skunk Bay Weather site in the northern part of the Kitsap Peninsula. Here is a video of it for your viewing pleasure. This event was associated with a Coronal Mass Ejection (CME) from the sun several days ago, which reached earth's orbit last night.  As a result, the Kp geomagnetic activity index climbed to around 5 (see plot below).  That is often high enough to get an auroral display around here.  It is still around 4. The interaction of particles from the sun and the earth's upper atmosphere and magnetic field produces a "donut" shaped areas of auroral activity, as illustrated by the short-term forecast of what happened last night. Disappointed about missing this celestial show? Don't worry, you may have another chance soon!   Another CME occurred and t

On Friday evening around 4:30 PM, strong winds ahead of powerful thunderstorms pushed across central Montana, resulting in localized duststorms in which visibility declined to near zero in seconds. As s result, at one location, (Hardin, Montana) a massive pile-up of cars and trucks occurred, resulting in six deaths and many injuries. Picture courtesy of Jose Strickland Such massive accident chains during dust storms are not rare. For example, several have occurred in Arizona and eastern Oregon/Washington, such as a 38-car crash near Prosser, WA in October 2003 (my NW weather book goes into this event and others) We understand the origin of such events, and as I will describe below, there are concrete steps, including new technology and meteorological guidance, that can hopefully reduce the frequency of such roadside carnage. The Montana Event The event on Friday occurred on Interstate 90, just east of Hardin, Montana (red arrow on map) That afternoon, a line of very strong thunderstor

We are two weeks away from the driest time of the year here in the Pacific Northwest. But why?   Why is the last week of July so arid around here, when that is not true over the eastern half of the U.S.? All is revealed in my Podcast (which you can listen to below). The West Coast is Very Dry in July.  While the eastern U.S. is Wet.  Why? And then there is this weekend.   It is not that it will be all bad, but our old friend, the east Pacific upper-level trough, will be visiting.....and, how do I say this politely?... such features are not associated with heat waves.   The National Weather Service weather icon for Saturday says it all: To listen to my podcast, use the link below or access it through your favorite podcast service. Some major podcast servers:     Like the podcast? Support on Patreon  Announcement I will be doing a special online zoom session for Patreon supporters on Saturday at 10 AM.  Come with your questions....and I will talk about the summer outlook as well. Patreo

 Some things in life are not fair.   We suffered from a cool/wet spring due to a persistent area of low pressure just offshore. Yes, it had its good points: eliminating drought, providing a bountiful snowpack, and suppressing wildfires.  But mildewed Northwest folks need a break with sun and warmth. And if we are ever going to get dry weather it should be now , since the second half of July is climatologically the driest period in the year, as shown below. But this is not a normal year. A threatening low-pressure area has been hovering offshore, and one of its evil progeny will push into our region on Saturday and Sunday. To see this, here is an upper-level map (500 hPa pressure level, about 18000 ft) for today at 11 AM.  You can think of the lines as pressure and blue/gray colors indicate pressures that are much below normal.  This is also known as a trough .   A ridge of high pressure is inland, keeping us near normal in temperature and relatively dry. But look at the forecast for S

 As I write this blog around 6 PM, marine air is surging into western Washington, with strong northwesterly winds pushing into the Strait of Juan de Fuca. At Race Rocks, south-southwest of Victoria, BC winds just gusted to 48 mph and the latest UW WRF forecast model predicts strong westerly wind gusts, reaching over 40 knots, in the eastern Strait at 8 PM (see forecast map below). We are now experiencing an onshore or marine push and the cool, dense marine air is moving in at low levels causing sea level pressure to rise.  Since the Cascades block much of the cool air from moving eastward, the pressure remains lower east of the Cascades.    Thus, the result of the low-level marine air instruction is to create a large pressure difference (or gradient) across the Cascades, as illustrated by the sea level pressure forecast for 8 AM Wednesday (see below).   The lines are isobars of constant sea level pressure, and you will note a lot of them over the Cascades where pressure is changing ra

There is a serious wildfire threat in eastern Washington right now, with a growing potential for large, fast-moving grass fires. For this threat to be realized, all it will take is strong winds and some careless ignition. I found huge amounts of annual grasses when I took a drive to  Thorp, Washington on Saturday.  Worrisome. Ironically, the key setup was the cool, moist spring we just completed, which led to bountiful grass production east of the Cascade crest.   The wonderful USDA Forest Service website fuelcast.net shows the situation clearly.  Below is a map of the current amount of annual herbacious plant material (such as annual grasses) in our region (I secured this from fuelcast). Substantial fuel amounts over the Columbia Basin and the eastern slopes of the Cascades, with large areas with more the 700 pounds per acres.  That is a lot of fuel for fire. How unusual is such accumulations of annual "fuels"?  The following graphic from fuelcast.net shows the deviation fr

This week I received a number of complaints about humidity.   Folks were sweating and icy drinks were drenched on the outside.  If one was from the eastern half of the U.S. one might laugh at such complaints, but one thing is true, the dew point temperature , a potent measure of atmospheric moisture was the highest of the past month, rising to near 60F (see plot of dew point at SeaTac below). My podcast talks about dew point temperature and tells you why it climated above normal earlier this week. My podcast also provides the forecast for the next week and talks about the mini-heatwave on Monday and Tuesday, when temperatures will surge into the 80s in western Washington, 90s in the Willamette Valley and over 100F in portions of the Columbia Basin (see forecast to 5 PM Monday below).  Cooler along the coast and northwest Washington. But by Wednesday, the cool marine air will come rushing back in. To listen to my podcast, use the link below or access it through your favorite podcast ser