AFTER A VERY MILD PERIOD...COLD TEMPERATURES ARE EXPECTED TONIGHT BEHIND TODAYS COLD FRONT. VERY DRY AIR...LIGHT WINDS...AND CLEAR SKIES WILL ALL BE CONDUCIVE FOR TEMPERATURES TO QUICKLY FALL THIS EVENING...WITH SUB-FREEZING TEMPERATURES FOR NEARLY ALL OF EASTERN UTAH AND WESTERN COLORADO ON SATURDAY MORNING. OVERNIGHT LOWS WILL BE AROUND 10 DEGREES BELOW NORMAL RANGING FROM THE TEENS FOR THE HIGHER MOUNTAIN ELEVATIONS TO THE 20S OVER MOST OF THE VALLEYS. TEMPERATURES TO THESE LEVELS WILL THREATEN TREES THAT ARE BUDDING OR BLOOMING...TENDER PLANTS AND ANY EXPOSED WATER PIPES.