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Thank the Omega Block for our warm, dry weather

Posted at 1:52 PM, Apr 15, 2016

WEST MICHIGAN — Despite the fact we’ve had some ups and downs in our weather the past few weeks with almost 10″ of snow just in the month of April alone (normal is less than 2″), and now this long, dry stretch of warm temperatures above normal…there is indeed a rhyme and reason for the madness. Thank (or blame it on) the last letter of the Greek alphabet Omega. The symbol itself looks like a horseshoe, but what does it have to do with our weather? Here’s the connection.

We’ve probably all heard about the upper level river of fast-moving winds we call the Jetstream. This stream of air moves (or carries) low  and high pressure systems across the country from west to east. When the Jetstream dips south, we call that a trough…usually characterized by cooler-than-normal temperatures and unsettled weather with precipitation. When the Jetstream pushes, bubbles, or lifts north, we call that a ridge…associated with a ridge of high pressure with warmer-than-normal temps and dry, sunny conditions.

Our pattern unfolding has a deep trough over the western and eastern United States, with a strong ridge of high pressure over the Midwest and Great Lakes. See photo attached to this story. The orange colored line shows the Jetstream location this weekend with the giant high pressure system in place, flanked by troughs of low pressure on the left and right. The shape resembles the Omega sign and is a type of blocking pattern. The storm track the past few days has been (and will be for a few more days) through the Rockies, Central, Northern Plains. It’s difficult for clouds and precipitation to penetrate the “wall” of dry air and this ridge. That’s why those of us underneath this bubble or ridge remain dry, cloud-free, and warmer than normal. Frankly, until the Omega breaks down, things won’t change. Any cold front that can sneak through the ridge is generally weak and moisture-starved.

All things considered, look for continued dry, sunny conditions through the entire weekend with only a slight chance of a shower Monday evening/night as a weak cold front slips through the state. Get the complete forecast at www.fox17online.com/weather.