Some Weather To Watch this Week

Nice lighting on the Catalinas at sunset last evening (Sunday, 10 November).

This morning a very serious cold front is heading down the northern Plains and south along the Front Range of the Rockies. The NAM 850 analysis at 5 am this morning (above) shows temperatures as cold as -14C over North Dakota, where morning lows fell to zero or below F. It looks like this front will backdoor into southeast Arizona during the night, as it plunges south all the way to the Gulf of Tehuantepec in Mexico. The 850 mb forecast below is valid at 5 pm pm MST tomorrow (12 November). This front will bring the Tucson area a period of strong easterly to southeasterly winds tomorrow and Wednesday.

The GFS long-term, ensemble forecasts are also interesting. As a strong 500 mb trough develops over the West, some GFS members bring subtropical moisture northward into the Southwest by the end of the week. At this time 7 of 12 members of the GFS forecast precipitation into southeastern Arizona for the 12-h ending at 5 am next Saturday morning. Above is the surface and precipitation forecast for then from one of the GFS members. So, this will be something to keep an eye on.