Thursday, December 17, 2015

Looking Toward Christmas

First a bit about low temperatures - yesterday morning was the coldest so far this season, here at the house, with a low of 21 F. The previous coldest was 23 F on December 2nd. There was a bit of damage here, as several Prickly Pear cactus (those located away from the warm adobe walls of the house) dropped limbs.

Looking ahead toward Christmas using the 192-hour forecasts from last evening, the global models indicate the next weather event may be around the 25th to 26th. The event that was earlier being forecast around next Monday has vanished from the forecasts; so much for that possibility

Above is the 192-hour 500 mb forecast from the operational ECMW, showing a strong system approaching the Southwest. The operational GFS forecast for the same time (below) indicates the system located a bit further west - but both models are trending toward a significant system in the Southwest by Christmas.

Both models also indicate a strong mountain wave over the Sierra Nevada Mountains northwest of Las Vegas. The GFS has a fairly substantial short wave over the Great Lakes Region, while the ECMWF has this feature off to the north and east, primarily impacting parts of eastern Canada.

The GFS ensemble plumes from 00 UTC last evening are just beginning to indicate the approaching system out at 192-hours in the QPF forecasts above. The temperature plumes below are of note for the rapid warm-up forecast for TUS tomorrow and Saturday.

More as Christmas approaches.

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