new mexico weather story by timothy shy of nws

We received the following description of New Mexico weather today from Timothy Shy, meteorologist at the National Weather Service:

New Mexico, especially the Four Corners region, is one of the cauldrons of the deep weather systems that get started here, and then sweep east to make weather and headlines across the plains and Appalachians, and on to the east coast.

The New Mexico Weather story is one of conflict between two basic regimes: warm air moving northward into the state from the tropics, and cold air plunging southward from the Gulf of Alaska and northeast Pacific along the U.S. west coast.

With spring, storms arriving over the southwest U.S. that have traveled southward from the British Columbia and Pacific Northwest coil up over the southern California coast. As these storms linger, strong west and southwest winds blow across New Mexico. With the sun gradually moving across the equator to warm more of New Mexico’s landscape, wind speeds become strong across the landscape, as faster moving air in the upper atmosphere works down to the surface. As storms move rapidly eastward into the central and southern plains, cooler air working in behind will return a hint of winter chill to New Mexico spring days.

Things change in the summer, as a long lobate ridge builds over the Gulf of Mexico, and surface low pressure deepens over the southern California deserts. Moisture pulled northward across New Mexico combined with moist southwest flow from the eastern Pacific set up the Southwest Monsoon, a period marked by showers and thunderstorms, and a significant contribution to New Mexico’s annual rainfall.

With the sun returning to the southern hemisphere in the fall, shorter days and less heating of the New Mexico surface produce a broad change in weather patterns. With storm tracks remaining to the north, and hurricanes and tropical storms remaining to the south, the state enjoys some of the classically best weather of its year. Sunny skies, generally light winds, and dry conditions dominate.

As fall closes and winter starts to open, storms in the Gulf of Alaska and along the Canadian west coast deepen and dive southward along the California coast, and stall as they ride over the warmer ocean waters of the tropics. As they stall, they begin an agonizingly slow eastward turn across the southwest U.S., spreading rain in advance, with rain changing to snow as the system moves through. Skiers love these systems, which bring the snow to the high peaks and lower valleys over the northern half of the state, and to the high peaks in the south. With colder air moving eastward and warm air returning, snow will melt from the valleys, but remain on the chillier mountaintops and in the high country near the Colorado border. The New Mexico winter is a winter of ups and downs and back and forths: winter as cold and blustery as neighboring Colorado, or as benign and warm as neighboring Mexico. As the sun returns across the equator once again, New Mexico returns to spring and the beginning of another year.

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