Wetand News

The third atmospheric river in a sequence will be directed towards our region tomorrow. Examining the situation, I was impressed by the rate at which this atmospheric river will be moving moisture into our region.   Specifically, the integrated water vapor transport (IVT), the product of water vapor and wind speed, is predicted to reach extraordinary levels tomorrow morning off our coast (see figure below).  Blue is high.  Purple levels are quite unusual, as is the great north-south extent of this moisture plume.    It is also coming almost from due west, rather than from the southwest as was true of most of the moisture plumes this fall. And the moisture/water vapor "river" of this event extends THOUSANDS of miles across the Pacific (see below).  Essentially from the Philippines to our door. This event will bring substantial precipitation to the regional terrain of Washington and Brtish Columbia, and with the moisture plume's west-east orientation, will bring one of the

Life is full of ironies and contradictions, and our weather situation of the past month is a wonderful example. A series of atmospheric rivers have moved into the Northwest this month, bringing above-normal precipitation on the western slopes of the Olympics and Cascades. Ironically, the SAME conditions that produce bountiful precipitation on the western slopes of our mountains cause drying over the downwind and lee slopes, resulting in profound rainshadows.   Huge precipitation contrasts reign. But to understand why this is true, you must understand the nature of atmospheric rivers. As I have mentioned in many blogs, atmospheric rivers are associated with plumes of large amounts of moisture from the tropics and subtropics that project into the midlatitudes.   For example, a well-defined tongue of moisture will be heading into our region this afternoon and overnight, as shown by a plot of such moisture at 10 PM tonight. This is a plot of integrated water vapor (IWV), which is th

The first of three plumes of moisture (atmospheric rivers) is upon us and moderate rain is currently observed along the coast (see radar at 8:30 AM).  If you are living in the interior of western Washington, NOW is the time to head out for some Thanksgiving exercise.  Rain will move in later this afternoon.  If you are in Oregon, you have the whole day. This first plume of moisture is associated with the first "atmospheric river" in a sequence of three. You can see the "river" in the satellite-based atmospheric water vapor image shown below. Lots of water vapor over the tropics, with thin tendrils of moisture heading into the midlatitudes, including one approaching our region. As I have explained previously, when such moisture is forced upwards by our terrain, moderate to heavy rain results. The media has recently discovered this term (atmospheric river), often hinting (or stating) that they are deadly or unusual.     Let me clarify things.  Atmospheric rivers a

Washington State and southern Brtish Columbia have experienced a very wet fall so far, with the atmospheric river of last weekend causing substantial flooding over Northwest Washington and the lower Fraser River Valley. But mother nature is not done with us ...we should not expect weather forbearance, considering that Thanksgiving week is climatologically the wettest, stormiest period of the year. Meteorological ground zero, so to speak. And to make the message clear:  not one, not two, but THREE significant atmospheric rivers will affect our region during the next seven days, with southern British Columbia getting the worst of it. Let me show you the predicted distributions of atmospheric moisture from the UW WRF modeling system. First, Thursday morning, with a potent atmosphere river of subtropical moisture aimed for northwest Washington State and southern BC.  A wet turkey day.  Sorry. By Saturday night ANOTHER atmosphere makes landfall in the same place!  And Tuesday afternoon an E

Last weekend there were highly damaging floods over Northwest Washington, with the town of Sumas and its vicinity being inundated by floodwaters.  Several landslides occurred, including some that closed  I5 near Bellingham. Town of Sumas, 2021, WSDOT Photo Within hours of this heavy rainfall event, politicians and the media were suggesting that this event was somehow unique and the result of global warming. For example, Governor Inslee called the flooding an example of  “a permanent state of attack by the forces of climate change.”   The New York Times claimed that flooding in Northwest Washington was caused by climate change (see below) Similar claims were found in the Washington Post and the Guardian.  And, of course, the Seattle Times had several stories, supported by a slew of "experts" (such as a Simon Fraser Professor) stating that climate change contributed to the flooding.   The truth is very different than these claims.    The Sumas area is extraordinarily prone to f

The coming weekend will be unusual for the region:  it will be totally dry as high pressure builds over the region! Sunday at 4 PM.  500 hPa heights (like pressure at 18,000 ft) This dry period is particularly welcome, allowing Northwest Washington a period to dry out before more rain comes in next week. But high pressure during fall can cause problems, allowing the surface to cool off to below freezing and allowing the possibility of roadway icing. My podcast describes this threat and how you can be on the lookout for potential signs of ice formation. You can listen to the podcast below or through your favorite podcast server. Some major podcast servers:     Like the podcast? Support on Patreon  Become a Patron! My next blog will be on the Sumas/NW Washington flooding, examining whether global warming is the cause, as claimed by some media and politicians.

 Today I have gotten several emails from folks seeing an unusual, if not disturbing, cloud pattern in the visible satellite imagery. I mean odd. As shown below, you can see the object of concern.....a nearly perfect rectangle in the low clouds (mainly stratus and stratocumulus) due west of Baja California Here is a closer view.   Wow. What is particularly odd  is that the box seems to nearly remain in place over time.  This is not normal. We have some international experts on low clouds in the subtropics in my department. In the past, several have talked about human intervention to modify such clouds artificially as a tool to reduce global warming. They assured me that no such experiment was going on and they could not explain this bizarre appearance. The Guardian newspaper also emailed about it, asking if this feature is the result of global warming.  I assured them that there was no reason to expect that to be the case.  And Charles Mudede, the self-styled "Green Mussolini"

 Extreme flooding forced by extraordinary precipitation has flooded the town of Sumas and other locales in Whatcom County. Landslides closed I5 and some other roads, and sewage overflows are threatening some water supplies in the area. The pictures are stunning. Downtown Sumas was flooded this morning. The nearby town of Everson is flooded. And landslides closed I5 near Bellingham: The Nooksack River achieved its all-time record river stage. The cause of these terrible conditions is very wet autumn followed by extremely heavy rainfall over the weekend.  Let me show you. Here are the 72 hr totals ending at 6 PM today.  A number of locations reported 8-10 inches...unbelievable... with 8.94 inches as Sumas Mountain and 9.88 inches near the international border.  Orcas Island, which is closer to the Olympic Rainshadow, got around 5 inches. But what made this even so deadly is that most of the precipitation fell in a 24-h period on Sunday (midnight to midnight).   This is shown below for th