What Ingredients Do We Need For Snow?
POSTED: Tuesday, December 17, 2013 - 10:16am
UPDATED: Tuesday, December 17, 2013 - 11:09am
What Is The Best Time Of Year And Weather Scenario For Borderland Snow?
Tuesday, December 17th, 2013 — Many people here in the Borderland, love to see to see snow, especially close to Christmas. Stay with NewsChannel 9 as we are currently tracking a system Friday that will bring in some area snow. This Pacific system looks cold enough to produce snow down to the 5500 ft. level. Right now definitely the southern Sacramento Mountains and the Gila Mountains in New Mexico should get a decent 4” to 6 of snow accumulation. ”There will also probably be snow accumulation over the Organ Mountains and definitely St. Augustine Pass east of Las Cruces. In El Paso, the tops of the Franklin Mountains could turn white. Stay Tuned!
Winter storms are usually associated with areas of low pressure known as cyclones. Under normal circumstances the winds across southern New Mexico and far western Texas blow from west to east during the cool season with the high mountains over California, Arizona and northwestern Mexico blocking any low level moisture heading our way. This explains why the region is so dry from late September through early June. However any time from November through early April our mild dry weather can transform into cold, snowy or even icy conditions within hours if a cyclone develops intensifies and moves across certain areas of the southwest.
Cyclones can be very complex but one important characteristic is the wind flow counterclockwise around the center of low pressure. As a result, the ideal set up for snow across southern New Mexico and Far Western Texas is the development of a strong cyclone or low-pressure center at the surface over southern Arizona or northwestern Mexico. Theses systems move eastward or southeastward across Northern Mexico, South of the New Mexico borders. A storm evolving and tracking in this manner can pull cold Arctic air from Canada as far south as Mexico at the surface causing temperatures to fall below freezing. Of equal importance, the cyclonic flow around the low will also pull moist air from the Gulf of Mexico northward where it is forced up and over the colder air at covering the surface. This process is favorable for snow or less frequently, ice.
Another contributing factor for producing snow is the elevated terrain. As air from the lower elevations to the east rises over mountains of New Mexico and western Texas, further cooling takes place, this further enhances the production of snow. Finally when low pressure in the upper atmosphere moves into Arizona or northwestern Mexico, it causes the jet stream to become more southerly to the east with strong winds aloft transporting moisture from the Pacific or Baja into the southern Rockies. The approach of the upper low and jet stream acts to strengthen the surface cyclone plus provides another source of moisture to increase the potential for heavy snow.
Major snowstorms can strike southwestern New Mexico and Far Western Texas any time from late autumn through early spring. El Paso, Texas was paralyzed when from December 13th-14th, 1987 almost TWO FEET of snow fell over the city. A surprise springtime snowstorm also dumped 17 inches of snow across the El Paso area from April 5th-7th, 1983.
The greatest threat of snow is across the mountains, especially the Sacramento Mountains and the Gila Mountains. Cloudcroft, which is almost 9000 feet above sea level, averages 84 inches of snow a year, which is, more than the annual snow for Burlington, Vermont or Duluth, Minnesota. Travelers must remember during the cool season that heavy snow may be falling over the mountains even when it is mild and dry across surrounding deserts.
The last couple of years the Borderland have seen snow around Christmas and the start of the New Year. I will continue to update you on this weekend’s storm system rain and snow potential. El Paso averages 6.6” of yearly snowfall, let us hope we see some of that this holiday season.
(Photo-Angela Zaragoza-NC9 Viewer taken January 3rd, 2013 -KTSM)