wxgeek's weather-Updated precip forecast Sept 14

Update Wed Sep 14

Ingredients coming together for a good soaking today and tonight. Upper level low current near Las Vegas and will continue to track towards the northeast through Thursday and provide ample moisture and instability. Surface cold front has made it's way along the front range this morning, and more cold air from Wyoming will reinforce the front later today and tonight to keep low level upslope flow going. Precip should start this afternoon, between noon and 3 pm, and become heavy at times this evening and tonight. Precip totals look to be between 0.5 and 1.0 inches for this event in the foothills, with possible higher totals in heavier thunderstorms, which will be embedded in rain at times this evening and tonight.

Snow level looks to remain at or above 10,000 ft, but some flakes are possible down to 9000 ft overnight. Only minimal accumulation below 11,000 ft, and would only expect accumulation on grassy surfaces below 11,000 ft due to warm asphalt. Bottom line is the drive up the hill and back down Thu morning should only be wet, but driving conditions in heavy rain and standing water still needs extra caution, and fog and low visibilities will also be present this afternoon into Thu morning.

Some precip and low clouds/fog will linger into Thursday afternoon. Upper ridge builds back in Friday through the weekend, so warmer temps back to seasonal norms and isolated afternoon/evening thunderstorms for Friday through Sunday.

Good news is this precip will significantly lower fire danger for a while. Winter Weather Advisory is in effect in the central and southwest mountains above 10,000 ft for 2-6 inches of snow tonight.

Long range progs have changed their mind about next week. Latest models now build a big upper ridge into the area which will keep temps above normal and dry for most of next week.

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We should see above average temps Monday and Tuesday, with only isolated afternoon and evening thunderstorms, which will mostly remain over higher terrain to the west. A pretty big change will occur on Wednesday when an upper level low that has been parked off the central CA coast kicks out and moves across CO. This will combine with a cold front moving down from the north. The combination will provide widespread rain and embedded thunderstorms by Wednesday afternoon that will persist into Wednesday night. Some areas could receive 0.25 to 0.75 inches of precip from this event. After passage of the cold front Wednesday afternoon temps will lower significantly and we will have upslope flow Wednesday night into Thursday morning which will cause fog and low visibilities in the foothills. Snow level should be between 10,000 and 11,000 ft Wednesday night, but I could possibly see a dusting down to 9000-9500 ft Wednesday night. Thursday should remain mostly cloudy and cool under an upslope flow with some showers and light rain persisting into Thursday evening.

Upper ridge then builds back into CO on Friday and temps will rebound to seasonal norms from Friday through the weekend. We will return to mostly dry conditions with only isolated afternoon/evening thunderstorms.

Long range progs indicate another cold front coming down from the north next week, which would again cool temps and bring increased precip chances. This cold front currently looks fairly strong and could bring snow down to 7000-8000 ft if current models verify.