The Great American Eclipse

The Great American Eclipse, August 21, 2017

Eclipse Stages

Image credit: Rick Fienberg

New July 4th 2017: We now have a video available expanding on the information below, you can check it out here.

On August 21 2017, a total solar eclipse will track from the Pacific coast to the Atlantic. The shadow of the moon will begin over Oregon and move east to Idaho, Montana, Wyoming, Nebraska, Kansas, Missouri, Illinois, Kentucky, Tennessee, Georgia, and South Carolina. The eclipse will begin in our area between 9:05 AM and 9:09 AM PDT. Totality for those within the path will begin between 10:19 AM and 10:29 AM PDT and last anywhere between 20 seconds and 2 minutes depending how close you are to the center of the path of totality.

Where can I see the eclipse?

All locations in our County Warning Area will see at least 93% of the Sun’s disk covered by the moon. Those very close to the inside edge of the red lines (such as the northern portions of Redmond) will only experience 20 to 30 seconds of totality, while those closest to the blue line will see up to 2 minutes. Only those areas in between the red lines will experience a total eclipse that includes stunning views of the Sun’s corona while those outside the red lines will only see a substantial darkening of the sky.

Blue line: Center of totality, near this line totality lasts a little over 2 minutes

Red lines: Northern and southern boundaries of totality

The view from outside the path of totality.

Image credit: Rick Fienberg

View of the corona inside the path of totality.

Image credit: Rick Fienberg

If you decide to endure the traffic and crowds and venture into the path of totality (and the weather cooperates) you will witness one of the most jaw-dropping spectacles in nature. The last total solar eclipse that was viewable from the Pacific Northwest was in 1979, and the next will not occur until 2045 in northern California.

What will the weather be like?

Forecast model solutions usually begin to diverge significantly beyond a week out. While broad trends in weather patterns be gleaned from them out to two weeks or more occasionally, specific forecasts for elements like cloud cover will not be well predicted this far out. Point based forecasts will become available on our website about a week out from the eclipse with additional forecast based decision graphics showing up a little before then.

Until we get to that point, we have to rely on climatology based forecasts to tell us what conditions will be most likely based on weather observations from previous years.

Luckily, the interior northwest is the most climatologically favored area in the country for cloud free skies in August in the path of the eclipse. We have a video detailing visual satellite imagery going back to 1979 for days surrounding August 21st, you can take a look at the condensed version in the images below.

Average Cloud Percentage

Ceiling Percentage

Average Cloud Cover at 11 AM PDT in August

Percent of Time Sky is More Than Half Covered by Clouds in August at 11 AM PDT

When significant clouds do occur this time of year they are generally associated with either a migratory low pressure system, or thunderstorms that form when a bit of North American Monsoon moisture finds its way this far north. On average these events combine to average 3 to 5 days in a typical August where portions of the eclipse path could be covered by clouds.

The end of August is just after our warmest point of the year with highs generally ranging in the mid 80s to lower 90s and relative humidities ranging from 20 to 30 percent in the afternoon in the lower elevations.

**Climatology for Locations in Path of Totality**
	Average High	Average Low	Record High	Record Low	August Days With Rain
John Day	86	47	103	35	3
Madras	82	50	97	38	2
Monument	90	48	110	36	3
Prineville	84	41	99	28	2
Redmond	84	45	96	34	2
Fossil	83	46	99	32	2
Dayville	90	48	108	39	3
Seneca	79	34	96	24	2
Long Creek	81	45	100	35	3
Antelope	84	48	101	33	2