KATU's Winter Weather Special: Decoding Winter in the Northwest скачать в хорошем качестве

KATU's Winter Weather Special: Decoding Winter in the Northwest

Predicting weather in the Pacific Northwest is challenging even on good days, let alone when winter weather is coming. The KATU Storm Tracker 2 Weather Team is here to decode winter weather. The Pacific Northwest is made up of dozens of microclimates. These locations control what happens to our weather daily. Columbia River Gorge: The Columbia River Gorge is the single largest factor when it comes to winter weather in the Portland area and southwest Washington and northwest Oregon. The gorge’s deep canyon walls and narrow passage create one of the most interesting meteorological setups anywhere in the world. As cold air descends from Canada, it spills over the Rocky Mountains and settles in eastern Oregon and eastern Washington. The air dams up against the eastern side of the cascades. An area of high pressure develops at the surface as the cold dense air sinks against the ground. When an area of low pressure begins to approach the Oregon coast, the wind begins to move westward through the gorge. As the air winds through the 80 miles, it begins to compress and speed up as the gorge narrows. As it makes it way past Crown Point in the western end of the gorge, wind speeds routinely exceed 100 mph as they spread out in eastern Multnomah and Clark counties. The cold air spreads out over Portland and then makes its way north into the Clark County lowlands and south into the Willamette Valley. As the area of low pressure gets closer, moisture moves up over top of the cold air, creating the classic Portland snowstorm set up. As long as the cold air keeps flowing out of the gorge, snow continues in the areas where the east wind exists. Without the Columbia River Gorge, the amount of snow west of the cascades would be almost nonexistent in our part of the region. Oregon Coast: The Oregon Coast is where most of our winter weather begins. Areas of low-pressure form over the Pacific Ocean and impact the Oregon and Washington coasts. Several times during the winter, we see atmospheric rivers deliver months-worth of rain in just a few days. One thing that we have started to understand is how these “AR” events play in snowstorms. When that cold air from the Columbia River Gorge gets pulled into the Portland area, and an atmospheric river moves in over the top of the cold air, we have seen snow amounts exceed ten inches several times in the past. In addition to potent rainstorms, we also see windstorms take shape along the coast. Areas of low pressure rapidly develop bringing winds to the coast and if the track of the storm is in the right place, winds can develop over the Willamette Valley. Western Washington County: The “Forest Grove Effect” When cold air moves in from the east, the air gets forced up against the coast range. The meteorological phenomenon is known as “cold-air damming.” Locally it’s known as the Forest Grove effect. The air can’t move anywhere and creates a dome of cold air that becomes thick enough to allow snow to fall as precipitation moves in overhead. Temperatures are often 5 to 10 degrees colder than locations at the same elevation just a few miles east. There have been several instances where Forest Grove and other communities along the east side of the coast range receive snow, while Hillsboro and Cornelius just have rain. The dome of cold air is tall enough that when the moisture moves in over top, it falls as snow. In areas where the cold air is not as thick, you see sleet or freezing rain occur. The same effect has been seen in central Oregon and Washington against the eastern side of the cascades. https://www.katu.com/local/katus-wint... #orwx #wawx #weather #winter #oregon #washington #meteorology #meteorologist #news #wind #rain #snow #snowfall #mountains _______________ Stay up to date with our social media: KATU on Facebook:   / katunews   KATU on Twitter:   / katunews   Subscribe to KATU on YouTube:    / @katunews   Daily News Playlist:    • KATU Daily News Playlist   For more information, visit https://katu.com/ Have a news tip? Send it directly to us: Email us: [email protected] Call the Newsroom: 503.231.4222 KATU is a OR based station and a ABC Television affiliate owned and operated by Sinclair Broadcast Group. Sinclair Broadcast Group, Inc. is one of the largest and most diversified television broadcasting companies in the country today. #KATU #Katu2abc #Portland #Oregon #localnews #oregonnews