Cascade Snow To Be Measured In Feet

An exaggerated jet stream pattern over the U.S. has led to some extreme rain and snow totals over the past several days, but changes are finally beginning.

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This pattern, known as an "omega block", established itself last weekend.

The jet stream took a big southward plunge over the Intermountain West as a large ridge of high pressure bulged over the eastern U.S. The jet stream dipped again off of the Eastern Seaboard (forming the Greek letter Omega).

A good analogy would be to place a wooden block in the middle of a running stream of water. The water is blocked from moving along and builds up on the left (or west) edge of the block. Storm systems caught in this type of pattern are often memorable. In the recent situation a storm system swung into the Rockies and was blocked from moving eastward, causing the storm to stall.

Moisture feeding into the storm fell as heavy, wet snow over a significant period of time across a section of the Rockies resulting in snowfall totals exceeding 4 feet in parts of Colorado.

Areas farther to the southeast, like central and southeast Texas, were inundated with torrential rain that created deadly flash flooding and the need for water rescues, especially in the Houston area.

(RECAPS: Deadly Houston Flood | Winter Storm Vexo)

There is some better news coming soon, however.

The "blocking" pattern is losing its tenacious grip and the ridge of high pressure aloft is sliding slowly eastward. At the same time, the storm system responsible for all of the heavy rain continues to drift northeastward through the northern Plains and Upper Midwest.

By Friday, the storm system will continue to progress northeastward and it will weaken considerably while the attending cold front will push eastward toward the Atlantic Coast.

This will bring a few days of dry weather to the southern Plains, including Houston and other parts of Texas. However, there are signs that a new storm system could bring more rain to the south-central states early next week, but details are uncertain.

(MORE: 7-Day National Forecast Maps)

Meanwhile, this pattern has created relatively warm and dry conditions in the eastern U.S. Late in the week, areas from the Great Lakes and Northeast to the Southeast will encounter some rain and slightly cooler temperatures. The cold front, and associated rain, will move offshore by the weekend. Rainfall totals in these areas will be generally light, so no flooding is expected.

PHOTOS: Photos of the Houston Flooding