Update Thu Feb 28
A sad goodbye to a wonderfully snowy February, March is not looking nearly as bountiful. Weak system will move north of CO today and bring snow to the northern and central mountains from this afternoon into Friday. Looking at 1-4 inches west of the Divide. A few flurries possible this evening and tonight for the foothills and plains, but most likely areas will be east of I-25 as northwest winds create downsloping and dry winds for the foothills. Big impact from this system will be winds for the foothills. Northwest to north winds of 25-50 mph will develop this afternoon and strengthen overnight into Friday morning. With recent snow, blowing and drifting of snow may become an issue across roadways, such as US 285 through South Park. Winds will gradually die down Friday afternoon. Temps will begin to warm Friday, with temps above seasonal averages by the weekend. Saturday likely to be the warmest day, as I think cloud cover will limit temps a bit on Sunday, but still warm for this time of year.
Next system to skirt north of CO will impact weather late Sunday into Monday. Snow chances increase across western CO by Sunday afternoon with nearly all snow remaining west of the Divide. Cold front will bring cooler temps to eastern CO Monday, but little if any snow expected for the foothills and plains from this system. Winds again will be the biggest impact. West to southwest winds will develop Sunday ahead of the system across the foothills and adjacent plains, then winds shift to west to northwest after cold front passes Sunday night, and continue into Monday morning, so a blustery day on Monday. Upper ridge then builds back into CO bringing above average temps and dry conditions across the state Tuesday and Wednesday. Models bring a new system into the picture next Thursday/Friday. Majority or precip looks to remain west of the Divide with this system as well, although better chances east of the Divide at this time. No significant snow makers appear on long range models through the middle of March.
Boy, that sure was a deep 2 inches of snow yesterday
![:) :)](/media/kunena/emoticons/smile.png)
As much as I hate busting forecasts, I am very pleased with the additional snow cover, it actually looked like winter this morning. With that 12 inches yesterday, we are now at 53 inches for February, which makes this the snowiest February on record (since 1993). Average for the month is about 20 inches using the long term average, and about 30 inches using a shorter term average from 2006. Comparing monthly averages from the longer term data versus my shorter term data indicates that monthly trends in snowfall have changed recently. The longer term data shows March and April being the snowiest months, while shorter term data shows the snowiest months being from December to February. Obviously not enough data to make any conclusions, but some interesting trends. We now stand at 84 inches for the season, which is now 94% of average snowfall through the end of February using the long term average, and 68% of average using the short term average. We still have a long way to go to get to our average seasonal snowfall (172 or 192 inches). Using longer term data, we would normally say we have our snowiest months coming up, but recent data suggest we perhaps should not expect as much snow in March and April as we used to. This combined with the latest climate outlook from the Climate Prediction Center that indicates we should expect below average precipitation from March through May and above average temps would still cause some concerns for water and fire danger. Hopefully the climate predictions are wrong and we see at least average snowfall into May. I will enjoy the snow pack on the ground while it lasts.
So now on to the forecast. A weak upper level trough will pas sto the north of CO Thu/Fri, and bring good chances for snow to the mountains west of the Divide Thursday into Friday morning. East of the Divide, models now suggest little if any snow. What looks very likely, is that very strong upper level northerly winds behind this system will bring strong surface winds to higher elevations and the foothills Thursday night into Friday morning. This northerly direction typically causes problems on US 285 through South Park, so with recent snow, expect blowing and drifting snow Thursday night into Friday, and possible road closures along 285 through South Park.
Upper level ridge builds into the western U.S. on Friday and will bring warm and dry conditions to CO. Temps will warm back above seasonal norms on Friday and Saturday under mostly sunny skies, so a good weekend to be outside if possible. Next upper level trough will approach CO on Sunday afternoon and bring snow to western CO Sunday afternoon into Monday morning. Currently looks like 4-8 inches possible across the northern and central mountains. Latest models suggest little if any snow will make it east of the Divide. Cold front will bring cooler temps on Monday and some gusty westerly winds, but not much in the way of additional snow.
Upper ridge then builds back in next Tuesday and Wednesday, so warm and dry conditions across the state. Next system could bring precip to western CO next Thursday and Friday, with a chance some could make it into the foothills, but too early for any confidence on that.
In general, recent long range models suggest the first half of March will be rather dry across CO. This tends to make sense as February was very wet due to a nice MJO that moved into the eastern tropical Pacific basin. That MJO has moved east, and no future MJO is currently on the horizon. MJO stands for Madden-Julian Oscillation, and if you want additional understanding of this phenomenon, here is a link describing the phenomenon and the influence on weather:
http://en.wikipedia.org/wiki/Madden%E2% ... scillation
(yes, I realize it is Wikipedia, but it has a very nice description and examples)