Wetand News

In many ways, meteorologists are in the art business, because many images produced by our models and observing systems are simply beautiful in their own right.  Many could be framed and would provide esthetic pleasure to most viewers. Perhaps among the most beautiful types of meteorological imagery are the satellite depictions of atmospheric water vapor.  Let me show you. Water vapor is a clear gas that is invisible to the naked eye. When you see a typical satellite image in the visible part of the spectrum (example below from today), you see the light from the sun reflected off the surface and clouds.   Water vapor in the atmosphere does not interact with visible light and so you can't see it.  Water vapor does interact with radiation in the infrared portion of the electromagnetic spectrum, where it both absorbs and emits radiation. NOAA GOES weather satellites have the capability of viewing the emission of water in the atmosphere.  In fact, the latest GOES satellit

You can probably tell by now that I am quite interested in astronomy... in fact, one of the most difficult decisions of my life was deciding between astronomy and atmospheric sciences..  I tried to bridge the gap by studying both as an undergraduate and working with Carl Sagan on modeling the Martian atmosphere.  But in the end, I went for atmospheric sciences. Anyway, tonight may be the best night yet to view Comet Neowise.  The sky is quite clear, with only a few thin cirrus clouds (see below). The atmosphere is very, very clean.   The Seattle PanoCam shows excellent visibility: And the latest air quality measurements show extremely clean air.  Looking at the particulates over Seattle, the values (PM2.5) are under 10 micrograms per meter cubed.   Take a deep breath--this is the good stuff. Sunset tonight is 9 PM.   My advice is wait until 10:45 PM to look, and it would be better to wait until 11:00 PM.   Astronomical twilight doesn't end until 11:35 PM...so th

One of the most extremely anomalies of Northwest weather is the tendency to get get very, very dry in late July. I mean we are drier than most of the eastern 2/3rds of the U.S..  Drier than Phoenix. And it happens very, very fast.  To illustrate, here is the probability of getting at least one-hundredths of an inch in a day at Seattle Tacoma Airport based on past climatology.  An amazing plummeting of precipitation probability from around 30% chance in a day for June to less than 10% during the last week in July.   From drizzly June gloom to late July sun. What causes this rapid desiccation of the Northwest? One big changes is that high pressure builds very rapidly  aloft during July.   To show that, here is a plot of the climatology of 500 hPa heights above Forks, on the Washington coast.  You can think of this like pressure at roughly 18,000 ft.  The black line shows the median value for each day.  The heights/pressures go up very, very rapidly in July to a peak in late

If you want to see one of the brightest comets of the past several decades, the viewing will be excellent tonight over the Northwest for comet Neowise. A picture taken by the Seattle National Weather Service last night If you want to view a spectacular video of the comet from Skunk Bay Weather on the Kitsap Peninsula, check this out: Our skies are clear or nearly clear today over nearly all the land area of the region, with the exception of the coast. There is no wildfire smoke to contend with. And the latest model cloud forecast suggests that excellent viewing conditions without clouds will continue for most areas tonight (see forecast for 11 PM tonight below).  Only the coast will be an issue. When and how should you view it? Because of our short nights and extended twilight, you have to wait at least an hour and a half after sunset (which is at 9 PM) to get a decent view.  So wait until 10:30 PM to check it out--and 11 PM would be better.  Middle of the night

The headlines are screaming about recent increases in coronavirus cases, with some suggesting that the essential problem is the loosening of the lockdowns and restrictions.  A number of media sources note that many of the problematic locations are "red" states with Republican leadership.  It is not surprising that moving out of lockdown resulted in more COVID-19 cases.  In addition, the increasing number of tests undoubtedly increases the number of known infected. But could there be something else going on? Could increased use of air conditioning, particularly in the southern tier of states, be a significant driver of increasing number of COVID-19 cases? This blog will attempt to help answer this question. So where is the virus really spreading?   A good way to see the problem locations is to view the percentage of positive tests.  A worsening epidemic is signaled by a higher percentage of positives, assuming there is widespread testing.  Positive percentage is

I got up at 3 AM this morning to view COMET Neowise.   The COMET had passed the sun on July 3, getting as close as 27 million miles, and is now moving back out into the solar system.  Its orbital period, the time to complete a loop from near the sun to location far beyond the planets, is 6800 years.  So you better catch it this time. It was not a little strange walking the streets to find a vantage point at 3:15 AM.   Some animals shuffled in the bushes and amazingly, there was some light on the northern horizon.   There is only about 2.5 hours of real night this time of the year and astronomical twilight had already begun when I was out there.   Extraordinarily, some folks were shooting off fireworks at the time and I could hear loud shouting in the distance. Perhaps their deep joy in seeing the comet. When I climbed to a good perch to view the northeast horizon, I was able to see Neowise----faint, but clearly visible.  Here is a shot from my smartphone. But if one wants

O K....we need a new name. Julanuary? Julember? Whatever the name, the last week has been mainly cloudy and well below normal in our area. According the maximum temperature anomaly map (difference from normal ) for Washington for the first seven days of July, the high temperatures in most of western Washington have been 6-12F below normal.     Even eastern WA has been generally cool. At SeaTac Airport, not a single day had the high temperature reached the normal values (low to mid-70s)--see below. Sunshine?     Much less than normal!  To illustrate, here is the solar radiation observed at the WSU AgWeather site in Seattle. We should be hitting a peak of about 950 this time of the year, but many days have been warmed by half or less (like yesterday and June 27th).   Just depressing. Normally, our region dries out rapidly after July 4th, with lots of sun each day.  Not this year.  Tomorrow?  Don't get your hopes up.  Another wet weather system is now approachin