As I have noted many times, Oregon has some of the worst weather radar coverage in the country, with a large radar gap off its central and southern coasts and another gap east of Oregon
Important weather features approaching the coast may be missed, reducing short-term forecasting skills from western Oregon to western Washington. Probably including the missed Portland blizzard on February 22nd.
Below is a National Weather Service radar coverage map, with yellow indicating areas of low coverage (coverage below 3000 ft above ground). Coverage would be much worse near sea level. West Washington and the Washington coast have good coverage thanks to the Langley Hill (Hoquiam) radar, the Camano Island radar north of Seattle, and the Portland radar.
But most of the Oregon Coast is uninsured. The Portland radar was blocked by low-lying coastal mountains and the Medford radar was poorly positioned, so high (7500 ft) that the radar beam reached the coast at 13000 ft and even higher. than offshore.
Eastern Oregon was a radar disaster, with no coverage for large areas.
So what are we missing with such poor radar coverage? What would we see if there was radar there?
I thought I could tell you, using our regional high-resolution forecasting system.
Believe it or not, we can simulate what a radar image will look like using 3-D precipitation generated by forecasting models.
Consider last night at 6pm. The short-term (2-hour) forecast predicts heavy rainfall along and off the central and southern Oregon coasts. Western Oregon is experiencing showers and some rain has crossed the Cascades into eastern Oregon.
Do not compare that predicted precipitation with what echoes indicated by the combination of all local radars simultaneously.
A big difference.
Nothing along the central and southern coasts. There is nothing immediate downstream of the Cascades in eastern Washington. Large gaps in radar coverage.
Want another example? Consider March 2 at 10 am. The model predicts a strong front extending from the coast of the Pacific Ocean into northwest Washington. Meteorologists need to know the details of such an important feature.
The weather radars receive the extension on land but NOTHING offshore. Very bad.
We cannot assume that our models will always be correct. During some periods, such as the recent Portland snow event, our best numerical models are wrong, even for short periods of time, and so we need to be able to keep track of what is to come. happen offshore. Only then can we provide the public with reliable forecasts and warnings.
State-of-the-art forecasting technology allows information from radars to be imported into short-term forecasting models, such as NOAA’s High Resolution Rapid Refresh (HRRR) modeling system. As a result, forecasts to the west of Washington are improved because we have a coastal radar (Langley Hill)
Oregon has no such coastal radar and therefore forecasts for western Oregon are impaired.
Hopefully some Oregon representatives and US senators will bring this up.
