The Oregon Coastal Radar Gap

It was 10:30 AM on Thursday morning and the forecast models predicted that a deep low center from a Pacific storm was moving up the Oregon coast.    For meteorologists, it was crucial to know exactly where the low was located, both to check the model forecasts and to improve upcoming model runs. The visible satellite image was not definitive, with an elongated trough and no clear circulation evident.   But the models were emphatic it was off the coast somewhere.  But where?

What did the National Weather Service weather radars show?

The new Langley Hill radar on the Washington Coast was too far north, since the low was probably off the southern/central Oregon Coast.  It did not show a circulation, since it was too distant.

The Portland radar, too far from the ocean and the lower beam blocked by the coastal mountains, showed practically nothing offshore.  We see this problem all the time--the Portland radar is not very useful for viewing coastal or offshore weather.

The Medford, Oregon radar, too far inland and too high (it is on top of Mt. Ashland at around 7500 ft) showed little offshore.   No help at all over the ocean.

Putting all the radars together in a composite, there is little evidence of the circulation around the low...or anything else off of Oregon.  Not good.

Four hours later, when the the low center was further north and in the range of the Langley radar, the swirling circulation around the low was evident.  But for critical hours we did not have a good fix on the low.

The problem?    A huge gap in radar coverage over the Oregon coast and coastal ocean west of Oregon.  Here is an official National Weather Service radar map that shows the problem.  As I mentioned in a previous blog, there is also a major gap in coverage on the eastern slopes of the Cascades,

Since storms often come from the southwest and west, that means a major metropolitan area (Portland) lacks proper (or any) radar coverage upstream.   And as illustrated with the storm this week, it hurts western Washington forecasting as well, but at a more extended time range.  The lack of radar coverage off of the Oregon coast is something that Portland TV meteorologist Mark Nelsen has been blogging about repeatedly.  He knows.

The lack of a coastal radar is a particular problem today, since the National Weather Service forecast systems, like the new High Resolution Rapid Refresh (HRRR),  assimilates all U.S. radars before they make their forecasts.   That means that the radar information is used to describe the atmosphere, which greatly improves the forecasts.  I have noticed that the HRRR often gets offshore structures that are only described by the Langley radar.  Imagine if we had a similar radar on the Oregon coast!

As we learned with the acquisition from the Langley Hill radar near Hoquiam, the National Weather Service will not fix this problem without intense local lobbying.  I tried contacting the Oregon congressional delegation, but they were not interested in talking to someone from out of state. Oregon State residents, businesses, and organizations need to work together, in concert with their congressional representatives, to make the case for an Oregon coast coastal radar and to push for its acquisition.