Winter Storm Maximus Ushers in a New Weather Pattern


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The omega block has broken down. Image courtesy of the NOAA

The omega block has broken down. Image courtesy of the NOAA

Winter storm Maximus will dump heavy snow on parts of the mountain west as the polar vortex directs its wrath away from the east coast. At least temporarily.

The Omega Block Breaks Down

The weather pattern known as an omega block for the shape of the jet stream flow, which has existed for weeks over the eastern Pacific Ocean, has given way to a more natural west to east movement of weather systems.

As the block breaks, the polar vortex is assuming a new position and shape. Storms are now more likely to affect the west, though they could re-develop in the Great Lakes and even on the Atlantic Coast.

Polar Vortex Still Dominates Weather Over the United States

The polar vortex, which has driven Canadian air down through the midwest and into the east for several weeks, is reorienting more east-west. It is still relatively powerful and farther south than normal, but the dip in the jet stream has now migrated westward and is shallower than previously. The cold air will be confined to the northern Great Lakes, the northern plains, and the western third of the country. The deep south and east coast will be warmer than normal.

Short Waves Traveling Through the Jet Stream

The overall pattern is set by the large-scale dips in the jet stream; but individual storms are caused by shorter, sharper troughs. The omega block prevented these short dips from reaching the west coast. Alberta Clippers formed along the eastern curve of the omega block and headed southeast into the midwest, then intensified as they reached the east coast.

Now, the short waves will roll through California and the mountain west, and some, like Maximus, will intensify in the Rockies and eastward into the plains.

Winter Storm Maximus Will Produce Heavy Snow in Denver

In contrast to the omega block, which spawned moisture-starved Clippers, the new pattern will allow an increase in the amount of moisture available to storms like Maximus.

Pacific Ocean humidity will accompany the storms and warm, humid air will move northward from the Gulf of Mexico. In addition, the position of Maximus will cause east winds on the east slopes of the Rockies; the upslope motion wrings the moisture out, and Denver can expect a foot of snow, with greater amounts in the higher elevations.

Winter Storm Maximus’s Path

After he visits Denver, Maximus will set his sights on the midwest. With the strong temperature contrast shifting to the center of the country, Maximus will have potential energy off of which to feed, and moisture from the south. If there is good news in this, it is that much of the precipitation will fall as rain; in addition, areas affected by snow will be more accustomed to it, and hopefully more prepared than the southern cities such as Atlanta – brought to a standstill by Leon.

A band of snow will stretch through Missouri, Illinois, Indiana, and Michigan, but Saint Louis should be on the rainy side; Chicago and Detroit will be on the snowy side of Maximus. Snow amounts should be generally less than six inches, with parts of Michigan getting more. There could also be a narrow band of freezing rain at the boundary between snow and rain.

More Storms to Come

With the polar vortex keeping the far northern states in an icy grip, and warm Gulf of Mexico air moving north, the stage is set for additional snowstorms in the general area of the strongest temperature gradient.

A second wave is now entering the west coast and will follow Maximus. If the storm is worthy of a name, it will be called Nika. Current indications are that it could form in the southern plains on Monday and reach the east coast by Wednesday. As with Maximus, there will be a large area of rain, but the northern portion of the storm will be snow and freezing rain — possibly a lot.

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