Spokane to Portland Maine Turbulence Forecast

GEG → PWM · 2,262 miles · ~5h 1m

What to Expect

The Spokane to Portland Maine route can be a mixed bag in terms of turbulence, mainly because it crosses so many different types of terrain. Departing Spokane, you might encounter some Mountain Wave Turbulence as you cross the Northern Rockies; this is caused by wind flowing over the mountains. As you head east over the Great Plains and the Upper Midwest, you could experience Clear-Air Turbulence, which, as the name suggests, occurs even in perfectly clear skies. Crossing the Great Lakes, there's a chance of Lake-Effect Turbulence, created by cold air moving over warmer lake waters. Further along, as you approach the Northern Appalachians, Mechanical Turbulence can occur, caused by wind interacting with the rough terrain. Finally, as you approach the Atlantic Seaboard, there is the possibility of Clear-Air Turbulence. Pilots are very familiar with these patterns and use weather forecasting to navigate the smoothest possible path. They constantly monitor and adjust course as needed to minimize any bumps.

The Spokane to Portland Maine route crosses the Northern Rockies, a rugged expanse of high peaks in Montana, Idaho, and Wyoming. Mountain wave turbulence is frequent here, especially when Pacific storm systems push strong winds over the Continental Divide. Pilots often report moderate chop between 30,000 and 40,000 feet over this region.

Turbulence Factors on This Route

• Mountain Wave Turbulence: The Northern Rockies generate powerful lee waves when Pacific fronts drive westerly flow across the high terrain.
• Clear-Air Turbulence (CAT): The jet stream frequently meanders over the Great Plains, producing wind shear and clear-air turbulence at cruising altitudes.
• Lake-Effect Turbulence: The Great Lakes produce lake-effect convection and low-level wind shear from land-water temperature contrasts.
• Mechanical Turbulence: The Northern Appalachians generate low-level mechanical turbulence during strong post-frontal northwest winds.

When Is This Route Bumpiest?

For the smoothest possible flight, aim for summer or early fall. The atmosphere tends to be more stable during these months, reducing the likelihood of turbulence over the plains and mountains. Late fall, winter, early spring, and early winter tend to be bumpier. This is when stronger winds aloft can create more Mountain Wave Turbulence over the Rockies and more Clear-Air Turbulence across the plains. The colder temperatures over the Great Lakes and the rougher wind conditions over the Appalachians can also increase the chances of Lake-Effect and Mechanical Turbulence, respectively.

Tips for This Flight

If you're concerned about turbulence, booking a morning flight is often your best bet, as the atmosphere tends to be more stable earlier in the day. Any turbulence you might encounter on this route will likely feel like driving over a series of small, unexpected potholes. Consider choosing a seat over the wing, as it tends to be the most stable part of the plane. Stay well-hydrated before and during your flight; dehydration can heighten anxiety. Remember that the flight crew is highly trained and experienced in handling all types of conditions, and their priority is always your safety and comfort.

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Forecasts based on NOAA HRRR and GFS atmospheric model data.