Wetand News

 Several blog readers have asked me about the impacts of a toxic release over Ukraine.  Where would it go?   Could the Northwest be in the line of fire? We are talking about the fallout from a nuclear device, leaking radiation from a damaged nuclear plant, or toxics associated with chemical or biological weapons. To explore this concern, I created air trajectories--showing the three-dimensional path of air parcels-- starting over Ukraine at three levels (6000, 7000, and 8000 meters above sea level).  This corresponds to 20,000 ft, 23,000 ft and 26000 ft ASL).  This work was done with the NOAA online HYSPLIT model and assumed the "event" occurred today at 11 AM and traced the trajectories for 240 hours. My mouth dropped when I saw the plot:  the two lower trajectories went right over Washington State (see upper panel below). But it is worst than that:  the lowest trajectories descended towards the surface in the latter half of their travels. The trajectories shown above would

If you want to take a very fast flight across the Pacific from Tokyo to Seattle, book your ticket on Sunday. Normally, such flights take about 8.5 hr.   But Sunday you will do it in well under 8 hours..perhaps as short as 7.5 hr--and I suspect the route will be more direct than normal. The reason: a nearly continuous, strong jet stream across the Pacific. As a reminder, a jet stream is a relatively narrow current of strong winds in the upper troposphere and lower stratosphere, typically found between 25,000 and 40,000 feet above sea level. To illustrate, here are the predicted winds (in knots) at around 38,000 ft (200 hPa pressure) at 5 PM PDT Sunday..  Reds and browns are the strongest winds-- with the most energetic winds of 150-175 knots (175-200 mph) A balloon released from Japan could make it across the Pacific (roughly 4700 miles) in roughly a day in a half.   The jet stream is the locus of clouds and storms and a map of predicted cloudiness (simulated satellite image) for 5 PM P

Meteorologists have no need to purchase artwork. The reason is that imagery from satellites, radars, and numerical models is often stunning.   Let me show you an example:  water vapor imagery from weather satellites. Most of the satellite imagery you see on TV and the media uses wavelengths that DON'T show you the atmosphere.  Visible satellite imagery shows you how much solar radiation is reflected off clouds and surface.  Infrared satellite imagery tells you the temperatures of clouds and surface, based on how much radiation they emit. But there are exceptions to this situation, and the most important is wave vapor imagery that displays the amount of radiation emitted by water vapor in the atmosphere.  Where the imagery is white, that means a great deal of moisture is in the upper troposphere (roughly 20,000-35,000 ft), where temperatures are relatively cool.  Dark shades indicate little upper-atmosphere moisture and plenty in the lower atmosphere. We are ready....let's look

 My new podcast addresses a question I am often asked.  How far into the future are weather forecasts skillful?   The answer has changed radically during the past three decades and I tell you why.   Just to motivate the discussion, here is a plot of the skill of the National Weather Service global model (GFS) for various lead times (blue bar).   The skill holds up well for the first four days, but you see a big drop during the second week.   This plot also shows the skill of ensemble systems in which many forecasts are made and averaged: the skill holds longer. My podcast also provides the weekend weather forecast and tells you where you can drive to experience the mid-70s!  See below on how to access the podcast. 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  Announcements With COVID declining, the department is starting public lectures, and the first one is a very g

During the past year or so, whenever there is a significant precipitation event on the West Coast, the media headlines "atmospheric rivers."   Ten years ago, hardly anyone talked about such rivers.  Now, they are mentioned all the time! To illustrate the change, here is the google trends analysis of searches on "atmospheric river" from 2004 to today.  Before 2010, almost no one was searching for the term.  But this November, it was very, very popular.  The same thing is true of mentions in newspapers and online. What has changed? Several people have asked me whether atmospheric rivers are a new weather feature forced by global warming. Others ask me whether global warming has made atmospheric rivers stronger and more frequent. Well, it is time to "clear the air."    The phenomenon now known as atmospheric rivers is as old as the hills.  They have NOT gotten stronger or more frequent on the U.S. West Coast, although they may in the future. I should note t

Throughout history, weather has played a critical role in war, and thus it may be of value to review the past, present, and future weather situation in Ukraine to garner insights into the future of this terrible conflict. Weather Conditions for Offensive and Defensive Operations Cloudy, rainy, and low-visibility conditions generally favor defense, since offensive operations--from aircraft-based attacks, intelligence collection from aircraft or satellites, and artillery targeting--are undermined by stormy, rainy, or cloud-enshrouded situations. February was drier and sunnier than normal over Ukraine, and was followed by a cool/cloudier period in early March.  During the last week anomalous high pressure has existed to the north of Ukraine (see upper-level map yesterday, below), producing warmer and drier conditions over the country.   This has been beneficial to Russia's offensive operations. Upper-level (500 hPa, about 18,000 ft) maps, with the colors indicating how much the situat

Residents of the Northwest are a savvy group regarding precipitation, considering their considerable experience with the wet stuff.    And the really precipitation-aware know about an interesting subtlety:  the late-winter precipitation plateau and the mid to late March transition over western Washington.  And the eastern Washington precipitation leveling during spring.  And more. To illustrate, consider the climatology precipitation at Seattle Tacoma Airport, showing the probability of experiencing 0.01 or 0.10 inches of precipitation in a day. The wettest period at SeaTac is from mid-November through early January, when the incoming storms off the Pacific are strongest and more frequent.  Then the probability of precipitation declines a bit in January, followed by little change through mid-March.  Subsequently, from the last few weeks of March through early May, precipitation significantly declines.   I call this the "spring drying."    Interestingly, there is a bit of an u

I am often asked about TV weathercasters.  Are they really meteorologists?  How good are their forecasts?      I answer these questions and more in my podcast. Western Washington has been lucky to have exceptionally talented and knowledgeable TV weathercasters, such as Steve Pool (left) and Shannon O'Donnell (right) And then this is ANOTHER atmospheric river coming our way later on Sunday.  Here is the forecast map of atmospheric moisture at 2 AM Monday.  The red and whitish colors indicate large amounts of moisture--headed our way. The bulk of the moisture will hit the northwest part of Washington and southwestern BC as shown by the accumulated precipitation through 5 PM Monday.  Very wet on Vancouver Island! More on the forecast in my podcast, as well as my discussion of TV weather. 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 

After the Ides of March I generally start thinking about summer water resources, with the snowpack, reservoir levels, and predicted Columbia River flow utmost in mind. The bottom line is that the state is in good shape waterwise for this summer. The snowpack is a bit below normal right now ---but not too bad at around 85% of normal for the State. Considering the snow that will fall during the next week (see forecast below), we will be in good shape snow-wise going into the spring.   And then there are the reservoirs.    The most critical is the Yakima reservoir system that supplies water to a lot of agriculture around Yakima and Selah (see below).   Wow.  These reservoirs are in tremendous shape....WAY above normal.     So full of water that we are about 2-3 months ahead of normal filling. Plenty of water for hops and tree fruit! Seattle's reservoirs are slightly above normal, and would have been hugely above normal, if Seattle had not released lots of water to prevent the

The ongoing tragedy in Ukraine has a number of meteorological dimensions, some of which will be touched upon in this blog. To begin, the war has essentially cut off surface meteorological observations over the region.  Below is the plot from a few hours ago.  Great density of weather observations over Europe....and even some over Russia....but virtually no weather data coming out of Ukraine.   Western Russian was pretty chilly...temperatures only in the teens (F).   We are now coming into mud season over Ukraine and vicinity, mud that has the bain of intended conquerors for centuries.   As shown in the climatological temperatures for Kyiv shown below, March is a time of very rapid warming, which results in the rapid melting of snow.                                                                    Graph courtesy of WeatherSpark And  in late spring precipitation begins to increase as well (see climatological rainfall below)' With warming temperatures, melting snow, and then increas