If the weather report is all the "news" you need, is it any more "accurate" than regular news?

 

There is a line in a Simon & Garfunkel song that goes “I can gather all the news I need on the weather report,” and I suppose for some occupations it is, like airline pilot or farmer. Because I don’t have a car and walk around outside a lot, I have to pay attention to the possibility of rainfall—and Seattle is supposedly one of the wettest cities in the country. But despite this reputation, it just seems that way because of constant cloud cover.

Seattle averages about 308 days a year of cloud cover, in which 226 are defined as “heavy” cloud cover; an average of about 150 days a year sees actual rainfall, but the rain is rarely heavy. While Miami averages 67 inches of rain a year, and New York City about 50 inches, Seattle’s updated yearly average is now 39.5 inches.

In NOAA’s October to September calendar—which at least in Washington correlates with the beginning of the official “rainy season” which lasts from October through March—we have seen the “official” precipitation level at 40.43 inches, which is already an inch above normal with a little less than five months till September 30. But that “official” climate data for Seattle is actually recorded further south, at Seattle-Tacoma International Airport, which is about 14 miles from downtown. Just how accurate is it in regard to what is happening in Seattle?

Let’s compare the precipitation numbers recorded at Sea-Tac with those recorded at King County International-Boeing Field, which is 10 miles down the road from Sea-Tac and four miles from downtown Seattle. First Sea-Tac:

 

Now Boeing Field:

 

Sea-Tac recorded 1.02 inches, while Boeing recorded .51, exactly half the amount. But it gets more interesting if we see what was recorded the previous day. First Sea-Tac:

 

And now Boeing:

 

Sea-Tac recorded .44 inches, while Boeing Field—which is technically within the Seattle city limits—recorded just .07 inches. Remember that these two locations are only 10 miles apart, and there are no significant geographical variables to explain it, just urban sprawl, and their locations adjacent Puget Sound’s Central Basin no different:

 

 

Being near a large body of water doesn’t necessarily mean there is more water to create rain through evaporation. Southern California is next to the Pacific Ocean, but sees little or no rainfall most of the year because persistent high pressure ridges keep precipitation that soaks the Pacific Northwest from moving south. It was another matter when I was stationed at Fort Hood, Texas, where it almost never rained, but when it did it was so torrential that "rain raid" alarms went off to warn people to seek immediate shelter. In Western Washington, coastal areas and the Olympic Peninsula can see up to 200 inches a year; I recall that the first six weeks I was stationed at Fort Lewis, which is located just outside the peninsula, it “drizzled” 24 hours a day non-stop. Yet locations like Port Angeles in the northern coast of the peninsula averages less rain a year than Seattle, caused by the “rain shadow” effect of the mountains in the Olympic National Park.

It’s still not “easy” to explain the differences in precipitation in two locations virtually right next to each other. Seattle supposedly is in the middle of a major convergence zone, with differing weather patterns from different directions effecting the weather, so that may explain how Sea-Tac and Boeing Field can have vastly different readings; in fact the latter can at times have precipitation readings while none are recorded at Sea-Tac at all—and this is certainly true even in Kent, which is 12 miles from Sea-Tac, and can see seemingly heavy rain but little or none is recorded at Sea-Tac, and vice-versa.

So if there is such a difference in precipitation amounts—and temperature, since “hot” air generated on the runways can blow toward the weather reading devices and record incorrect air temperatures by a few degrees--why is Sea-Tac still the "official" weather-reading station in the area (sure looks "high-tech," doesn't it)?:

 

 

We are informed that it is not important what the numbers coming from Sea-Tac Airport are as they relate to the region as a whole; they will continue to be the “official” numbers for Western Washington because its data has been recorded for a longer period than other weather reporting stations (over 75 years), and thus it is more useful for meteorologists to gauge climate changes over the years.