Steady rainfall is not a new thing in the Pacific Northwest. But the next round, which begins Tuesday, could cause flooding.
Setup
A slow-moving cold front is approaching the region from the Pacific Ocean. There’s enough moisture and instability to produce persistent rainfall for a few days. Rain may be heavy at times and thunderstorms could pop up in some places along the Interstate 5 corridor from Seattle to Portland, Oregon.
There’s potential for 3 to 6 inches of total rainfall over the northern and central Cascades, just north of the Seattle metropolitan area in Whatcom, Skagit and Snohomish counties, Washington. Rivers will begin rising Monday night, cresting late Thursday into Friday. The Skagit, Nooksack and Stillaguamish rivers may reach flood stage beginning Wednesday night.
The National Weather Service (NWS) has not yet issued a flood watch or flood warning for these areas, but this will likely change once the rainfall increases and starts spreading over the region.
Later in the week, this system will finally head to the east as a snowstorm, hitting the Rockies, Upper Midwest and portions of the Sierra Nevada.
Impact on freight
The Pacific Northwest is mostly made up of backhaul freight markets. This means there is more inbound freight than outbound, which leads to excess capacity of trucks and drivers.
SONAR ticker: HAUL map with forecast radar for Monday, Nov. 3, 2020, 2 p.m. EST
FreightWaves SONAR data shows backhaul markets in red and pink on its Headhaul Index (HAUL). The rainstorm over the next few days will mostly affect drivers heading into the Seattle and Portland markets to drop off freight.
Wicked winds
High winds will kick in Wednesday across Montana, impacting drivers on sections of I-15 and U.S. Highway 2. Dangerous crosswinds from the southwest will gust to 60 or 70 mph in Cut Bank, Havre, Great Falls, Helena and places in between. This will make deadheading — pulling an empty trailer — or carrying light loads especially risky.
The NWS has posted a high-wind watch for these areas from Wednesday morning through Thursday evening.