An Omega Block resembles the Greek letter Ω (Omega). It forms when the jet stream dips over the East and West Coasts while a ridge builds over the Central Plains. This setup allows storms to track along the jet stream, bringing unsettled weather to both coasts. Temperatures in the central part of the country are expected to rebound quickly, climbing into the 80s and 90s by Thursday. Cooler and wetter conditions will finally return to the Pacific Northwest which is experiencing one of its top-10 warmest and driest summers.
NEW YORK – After a couple of weeks under a stagnant weather pattern, things are finally shaking up across the continental U.S. as an Omega Block weather pattern will bring summer temperatures roaring back across the heartland, in addition to much-needed rain for the Pacific Northwest.
An Omega Block refers to dips in the jet stream where a large area of high pressure is bookended by two areas of low pressure, causing the pattern to resemble the Greek letter Omega (Ω) on a weather map.
This particular Omega Block will begin to develop tomorrow as high pressure finally returns to the central U.S., sending temperatures into the 90s and an area of low pressure brings more intense storms to the Pacific Northwest, which is experiencing one of its top-10 warmest and driest summers on record.
WHAT IS AN OMEGA BLOCK?
(FOX Weather)
Approaching triple-digit temperatures across parts of central US
After a couple of weeks of wet weather and some October-like temperatures, summer will make a comeback Thursday with temperatures in the 90s across the southern Plains and extending as far north as St. Louis, Missouri. Even Chicago is expected to crack the 80-degree mark.
By Friday, some 130 million Americans will be experiencing temperatures 10-15 degrees above average, feeling more like the middle of summer. The hot weather will persist through next Monday.
The ridge of high pressure building over the middle of the country will send storms from the West tracking along the jet stream into Canada before descending back to the East Coast. Thus, the Northeast will stay slightly cooler than average through Monday.
SEPTEMBER SKYGAZING GUIDE: SATURN SHINES BRIGHT, CORN MOON AND AUTUMNAL EQUINOX
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Rain to bring wildfire relief, flash flood threat to Pacific Northwest
Parts of the Pacific Northwest are already seeing some rain but a second, more intense round of storms will move into the region Thursday as the Omega Block weather pattern takes shape.
This rain will be beneficial for much of the Northwest which is in drought, according to the U.S. Drought Monitor. The region as a whole is experiencing one of its top-10 driest and warmest summers on record.
A Level 1 out of 4 flash flood risk has been issued by NOAA’s Weather Prediction Center across much of the Northwest and Northern Rockies through Sunday morning. A widespread 1-2 inches of rain is expected through the weekend.
A Flood Watch is in place now across portions of Oregon with the possibility of debris flows due to excessive rain over recent burn scars.
LIGHTNING STRIKES, DRY CONDITIONS SPARK DOZENS OF NEW BLAZES IN CALIFORNIA
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Wildfires, many of which have been caused by dry lightning, are burning across the region with little to no containment due to the dry conditions.
Smoke from these fires have created air quality issues for Washington, Oregon, Idaho, Montana and Wyoming at varying points this summer.
According to the FOX Forecast Center, the rainy weekend should help boost firefighting efforts.
(FOX Weather)
The precipitation will likely be too far north to help quell the Garnet Fire, which prompted Dense Smoke Advisories for parts of Central California and Nevada earlier this week.
