High-impact storms to create tricky holiday travel

Travelers will be heavily impacted by Mother Nature this week across a large part of the country (see Fig. 1). A potent storm system is taking shape across the Pacific right now and will move into northern California & southern Oregon late Tuesday night, eventually impacting most of the western United States. To give you an idea of the forecast intensity of this storm, it is expected to rapidly deepen and pack winds up to 80 mph (that’s the wind strength of a Category 1 Hurricane).

Fig. 1: Storm threats through Thursday

This storm will move inland Tuesday into Wednesday aiding in heavy mountain snow, valley flash flooding and damaging wind gusts across parts of the West. The California Sierra-Nevadas will be walloped with heavy, wet snow through Thanksgiving. 2-3′ are possible within the higher elevations. Snow levels will drop to 4,000′ as the system begins to depart. The valleys will also receive heavy precipitation. This precipitation will fall in the form of rain. 1-4″ are possible with flash flooding a real threat in the valleys. The greatest flash flood threat, and mudslide threat, exists near burn scars. 

National Weather Service offices have issued numerous winter weather products (Watches, Warnings and Advisories) for the region (see Fig. 2). Oregon, California, Nevada, Utah and Idaho will all see impacts from this storm. As the storm ejects toward the east, impacts will be felt across New Mexico, Arizona and Colorado by late week. New Mexico will see a double punch as moisture off of the Pacific will generate a wintry mixture by Wednesday. This wintry mixture will spread into the Texas & Oklahoma Panhandles. 

Fig. 2: Current western winter weather alerts

The West isn’t the only part of the country dealing with high-impact weather that will impact travel. The Rockies east into the Plains will see moderate to heavy snow accumulations through mid-week as a low develops on the east side of the Rockies. A heavy swatch of snow will occur on the north side of this low extending from Colorado east into Nebraska, southern Nebraska & northern Kansas. Eventually, Iowa, Minnesota & Wisconsin will get in on the action. Widespread 6-12″ are expected in this region with isolated 1-2′ amounts near the Rockies and close to Lake Superior. As this storm intensifies, winds may gust between 40 to 70 mph, which would greatly reduce visibility. Winter weather alerts are in place for part of the Rockies and Plains (see Fig. 3).

Fig. 3: Current Plains winter weather alerts