Why the Seattle weather?


For over a week now the forecast has sounded like a broken record… “cloudy, rain, fog, drizzle, etc.” October is not traditionally a soggy month for Hampton Roads. In Norfolk, we average 3.42″ of rain for the entire month of October. We have already topped that mark and we are less than half way through the month. So why do we seem to be stuck in this Seattle-like weather pattern?

Generally speaking, weather systems have to be pushed or steered in to (and out of) an area. In the case of tropical systems, the tropical easterlies or trade winds combine with the westward flowing warm waters of the Gulf Stream to move systems from the African Coast toward North America. In the case of an area of low pressure or a front, the Jet Stream does much of the steering across the U.S. So what has caused our Coastal Low to be “stuck” off the Mid-Atlantic coast?


Let’s start with a look back… This system started as Tropical Storm Karen in the Gulf of Mexico. It lost its tropical characteristics on Sunday, October 6th near the panhandle of Florida. The leftover clouds, rain, and area of low pressure were pulled up the East Coast along an approaching front. As the front cleared the coast line it fell apart, leaving the low (Karen leftovers) behind.

Since then the pattern has been quiet. No fronts moving through courtesy of a big ridge in the Jet Stream. (Side note: The Jet Stream is an area of fast moving air in the upper atmosphere that acts as a “highway” for weather to move along.)

This is what the Jet Stream has looked like for the past several days. Big ridge off the Pacific Coast, big trough over the Rockies, and another ridge over the East Coast. That means that any weather systems (fronts, lows, etc) that impact the Rockies will be pushed north over the Great Lakes or push south over the Gulf states. The end result… nothing pushes our coastal low out to see and we stay stuck in the pattern.

JetStream The good news is the Jet Stream moves! (just relatively slowly) We should start to see a pattern shift later this week. At least enough of a shift to allow a cold front to move through and break us out of this Pacific Northwest pattern.