Wetand News

The Northwest Weather Workshop is the big local weather meeting of the year and it will take place online on Saturday, May 7th.    Anyone interested in Northwest weather and climate is invited to attend. If you are interested, check out the meeting website, which includes the latest agenda: https://a.atmos.washington.edu/pnww/ This year, the meeting will include several talks on the June 2021 heatwave and a session on wildfire meteorology.  Plus, more general presentations on local meteorology, regional climate, and weather technology. You must register on the above website to attend:  the zoom link for the meeting will be emailed to you the week before the meeting.  The meeting is free. This is hopefully the last year that the meeting will be virtual. See you there!.....cliff

 Had enough of the coldest mid-April on record?     Problem solved.  The frigid temperature regime is over. But there is a catch.  T he atmosphere is transitioning to a new regime, where the weather will be cloudy and wet over the Northwest and northern California. A deep trough of low pressure will settle in over the northeastern Pacific, as illustrated by the forecast upper-level flow at 500 hPa (about 18,000 ft) for the next ten days.  The blue colors indicated whether the upper-level heights/pressure will be lower than normal...something called a trough. A strong trough offshore means lots of clouds and precipitation over our region.  This is not a particularly cold pattern. Take a look at the predicted precipitation through Wednesday afternoon.  Oranges and reds are the heavy stuff, with lighter precipitation in green and blue.   Precipitation everywhere, but heaviest over Oregon and northern CA, where they need it.  Good for water resources. The precipitation total through Saturd

Several readers of this blog asked that I provide a summary of my views on global warming. To respond to these requests, I dedicated most of my Friday podcast to this issue--so please check it out (you can access the podcast below or through your favorite podcast service). For those who don't like podcasts, let me give you my bottom lines: 1.  Greenhouse gases (such as CO2 and methane) are increasing and human emissions are the main cause of the rise. 2.  The planet has warmed about 1°C during the past century and most, but not necessarily all, of that warming is due to increasing greenhouse gases in the atmosphere. 3.  Increasingly greenhouse gases affects some extremes (e.g., heat waves), but not others  (such as the intensity of winter storms reaching the Northwest) 4.  Changes in extremes due to global warming are relatively small today and generally eclipsed by natural variability.  Changes in extremes (such as heatwaves) will increase later in the century. 5.  Global warming

We are in the middle of one of the extreme cold periods in Northwest history.  Many locations are breaking daily and MONTHLY records for coldest maximum daily temperatures in April.  And to drive the point home, snow showers were observed around Seattle (see a WSDOT image from Auburn this morning). Let's consider two-day average temperatures for April.   The last two days were the COLDEST at Seattle in April for the entire record (77 years). Olympia?   The last two days were the coldest for April: Pasco?  Monday and Tuesday were the coldest as well: Yakima?  The last two days were the coldest. Daily and monthly records are falling throughout the region.  Consider Monday, April 11.. Daily records  for the coldest high temperatures fell over the region (see below) More impressively MONTHLY records also fell that day. What about the low temperatures today?   Below freezing all over Washington and Oregon with teens in the mountains.  This is April folks...we are experiencing late Decem

This may well end up as one of the coolest mid-Aprils in Northwest history. One sign was the great Portland snowstorm of April 11th, where several areas around Portland received 2-6 inches of wet snow.   Branches were broken around the region, leading to nearly 40,000 people losing power. A Portland sidestreet.  Picture taken by Justin Sharp A backyard with roughly 6 inches of snow.  Courtesy Justin Sharp. The temperatures the last few days have been record-cold throughout the region.   Consider the temperatures at Seattle and Kelso-Longview in western Washington for the past four days (see below-normal highs shown in purple and normal lows are cyan).  Temperatures were 10-15 degrees below normal, with some days the HIGHS are near the normal lows.  January in April. The forecasts for the next few weeks are EXTREMELY cool.   Below is the forecast anomaly (difference from normal) for surface temperature over the region.  Can't believe it .  Vast portions of our region are 10 degrees

 Portland residents will be telling their grandchildren about this one. The great Portland April snowstorm. The latest NOAA/HRRR forecast shows bountiful snowfall over the lowlands of SW Washington and NW Oregon for the 24 h ending 5 PM Monday, with several inches around Portland.    A drive down I-5 tomorrow morning may be exciting.  A drive through the Gorge could be dangerous.  And the southern Cascades will be hit hard. The even higher resolution UW forecast model has a similar solution (see below) This snow is very welcome, considering that the Oregon snowpack is currently below normal.  A late-season snow blast has a major impact on fire season. Why this extraordinarily late cold/snow event? We start with a very deep upper-level trough (see the forecast for 5 AM Monday below for 500 hPa...about 18,000 ft).  Very impressive. And this trough induces a deep low center (see the surface forecast for the same time), which draws in cold air from the north.  In addition, heavy p

  If you are living in western Washington, the next 48-h will afford your last chance to see some falling snowflakes. But don't start thinking about sledding and snowballs--there will be no lowland accumulation. Although it is unusual, snow has fallen and accumulated over the Washington lowlands in April, something shown by plots of extreme snowfall amounts in Seattle and Bellingham below. We have a chance this weekend and Monday....but then it will turn too warm for the remainder of the month. The freezing level over us right now over Puget Sound is now around 1700 ft.  Colder than freezing above and warmer than freezing below.  Most precipitation starts as snow high up and takes about 1000 ft to melt when it falls into above-freezing temperatures. Thus, right now, wet snow could fall to around 700 ft. The atmosphere will cool a bit tonight and precipitation can cause the atmosphere to cool from melting and evaporation.  So snowflakes will be able to descend lower tonight. As show