Yesterday's high was 74. Today, we still climbed into the low 60s. Tomorrow, we shall drop to 56 with cloudy skies. However, the polar jet stream sets up a pattern on Tuesday that I have not seen in years. It turns south over Western Canada and aims straight for Arizona. This will pull in very cold air starting Tuesday night. In addition, a low-pressure system will bring snow chances both Wednesday and Thursday. Your 9-Hour Forecast for Monday and your general forecast are below... TONIGHT:     The skies will be partly cloudy overnight, and the chilly north breeze will range from 5-10 mph.  The low will drop to 31 at the airport, 28 in the valley.  FORECAST:    KTSM has issued a Weather Authority Alert for a significant and sustained drop in temperatures as well as snow accumulations starting Wednesday.  Monday will be partly to mostly cloudy and cooler with a high of 56.  The NE-E winds will range from 5-20 mph, a little gusty at times on the west slopes.  Tuesday will be mostly cloudy to overcast but dry with a high of 49.  Late Tuesday night, prepare for strong east-NE winds as a cold front pushes in.  Wednesday will be cloudy and very cold with a high of 35.  Expect scattered snow showers starting early in the morning and lasting on and off through the day with light to moderate snow accumulations (2 to 5 inches) by Wednesday night.  We drop to 21 that night.  Thursday will be cloudy and cold with a high of 38. Again, expect more scattered snow showers on and off through the day as a low-pressure system moves through.  We are likely to rack up additional snow by Thursday night.  Skies start to clear on Friday with a high of 46.  Saturday morning, skies will be clear, and temperatures will drop to 14 at the airport, close to 10 in the valley.