Turning Colder, Chance of Rain/Snow Showers; White Christmas Only a Dream?

19 December 2013   Dr. Curtis James

The figure above indicates the forecasted high in orange (with error bar denoting the range of ensemble forecast members), average high for this time of year in orange (dashed line), forecasted low in blue (with error bar), average low this time of year in blue (dashed line), and forecasted wind speed in purple. Note that the wind speed forecast is sustained wind (not gusts), and it is based on only one model (not an ensemble).

Weather Discussion:

Much cooler weather in store for tomorrow as an upper-level low pressure system digs south and moves eastward across southern Arizona. The system will produce breezy south to southwest wind and daytime temperatures up to 15 degrees cooler tomorrow. Expect partly to mostly cloudy skies Thursday – Friday with a good chance of rain showers Thursday night – Friday morning, possibly changing over to wet snow showers Friday afternoon to Saturday. Light rain or snow showers could persist through the day on Saturday. Snow accumulation, if any, will be light.

A strong ridge of high pressure will return next week, for temperatures rising back up to near 60 on Christmas Eve and Christmas. There may be some patches of snow on the ground this Christmas, but no new snowfall is expected on Christmas. Based on a consensus among all of the long term forecast models, we can only dream of a white Christmas.

If it isn’t white, here’s hoping it’s merry for all of you!

C. James

Met Mail is an unofficial weather discussion and forecast transmitted once or twice a week via e-mail by the Embry-Riddle Department of Meteorology (http://meteo.pr.erau.edu/). Embry-Riddle offers an undergraduate bachelor-of-science degree program in Applied Meteorology. Please spread the word to all potential qualified candidates!

Further Information:

ERAU Applied Meteorology degree program

Official National Weather Service forecast

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