wxgeek's weather-Weather Outlook March 13-25-Update 3/18-afternoon

Showers beginning to move into western CO this afternoon related to upper trough over CA. Precip will spread east to about the I-25 corridor by this evening. Snow level currently at or above 10,000 ft and will lower to near 9000 ft by midnight as precip spreads across all of CO. Precip will become moderate to heavy at times tonight into Thursday morning as snow level lowers to 7000-8000 ft by Thursday morning. Precip will begin to diminish from north to south by late Thursday morning into Thursday afternoon, ending by evening. Snow level remains around 8000 ft during the day on Thursday. Latest models have reduced precip amounts some, but seem more realistic with amounts generally around 1 inch of liquid equivalent. Heaviest precip will be from the Divide east to about I-25, but will cover much of state. For the foothills, believe precip will turn to snow above 9000 ft tonight lowering to 7000-8000 ft by morning, but nearly all accumulation will be above 8000-9000 ft. Winter Storms Warning in effect for mountains between the Divide and the Front Range Crest, and Winter Weather Advisory for the foothills above 6000 ft. For snow amounts, areas in the mountains and foothills above 9000 ft could receive 5-12 inches of wet and heavy Spring snow. Areas between 9000 and 7000 ft could receive 3-7 inches. Roads below 8000 ft likely to remain mostly wet, but could be snow and ice packed above 8000 ft by Thursday morning, then become mostly wet by Thursday afternoon. All in all, a good soaking moisture event for much of CO, which is needed.

Skies clear and temps return to near seasonal norms or above by Friday. We should have another nice weekend, with mostly sunny skies and temps above seasonal norms with only a chance for showers across the south central mountains. Early next week should remain dry and mild.

Next precip chance will be from next Tuesday afternoon through Thursday afternoon. Cold front moves through late Tuesday with showers mostly west of the Divide. On Wednesday, uplsope flow and colder temps create snow across much of eastern CO with several inches possible for the foothills and Urban Corridor. Conditions clear by next Friday and look to remain dry and mild into next weekend.

_________________
"Climatology is what you expect, Weather is what you get".

"It is better to be roughly right than precisely wrong".

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So last look at latest models indicating a lot of precip will fall over the mountains, foothills and Front Range corridor from Wednesday afternoon into Thursday night. Assuming liquid equivalent will be from 1 to 1.5 inches, areas above 9000 ft could see up to and possibly over a foot of wet and heavy snow, with areas down to 8000 feet seeing up to 4-8 inches. Thus, roads above 8500-9000 ft could become snow packed by Thursday morning. NWs has issued a Winter Storm Watch for areas from the Divide east up to the western foothills above 9000 ft. For lower areas, this will be a good soaking.

_________________
"Climatology is what you expect, Weather is what you get".

"It is better to be roughly right than precisely wrong".

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A Happy St. Patrick's Day to all. After some morning low clouds, clearing out in most areas across eastern CO although some pockets of low clouds hanging on along the Palmer Divide. Temps near to below seasonal norms today.

Then the forecast gets interesting for the remainder of the work week. Most models have remained consistent in bringing good precip chances to most of CO Wednesday afternoon through Thursday evening. The question is how much precip. NAM forecasts 1-2 inches of liquid equivalent, GFS from 0.5 to 1.5 inches, while the ECMWF is much drier, less than 0.5 inches. Models seem to be picking up moisture from 3 sources, one upper trough over TX, one moving in from CA and one moving south from the northern Rockies. In general precip chances begin across western CO Wednesday afternoon, and move east to about I-25 by Wednesday evening. Snow level begins around 10,000 ft Wednesday afternoon, and lowers to near 9000 ft by Wednesday evening, then down to about 8000 ft overnight Wednesday, and possibly down to 7000-8000 ft Thursday morning and during the day on Thursday. Precip looks to end Thursday afternoon into Thursday evening and move south. So it appears most of eastern CO will have a decent wetting with anywhere from 0.5 to 2.0 inches of rain. The question remains how much snow will fall above 8000 ft. I believe snow will not really be an issue until after 9 pm to midnight Wednesday night for foothill areas. But by Thursday morning to evening, areas above 8000 ft could pick up several inches of wet and heavy snow. Much of initial snow will melt with warm temps this week, and temps will be warm enough Thursday that snow will have a hard time sticking except on grassy surfaces, but higher foothill areas could see 3-7 inches of snow by Thursday night. Mountain areas could also see 4-9 inches of snow above 8000-9000 ft.

Friday through Sunday looks mostly sunny with temps back above seasonal norms. Some showers may be possible each afternoon, mostly over higher terrain along the Divide. Early next week also looks dry and mild.

Next precip chances look to be Tuesday night into Wednesday night as a system passes to our north. Models indicate a cold front will drag across CO which will bring in cooler temps on Wednesday with snow down to plains level, although majority of precip will remain along and west of the Divide with this system. Conditions then look mostly dry and mild from next Thursday into next weekend.

It appears likely March will end with well below average snowfall for nearly all areas of CO, which puts a lot of pressure on a wet/snowy April and May if we have hopes of recovering to near normal seasonal snowfall.

_________________
"Climatology is what you expect, Weather is what you get".

"It is better to be roughly right than precisely wrong".

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Spectacular early Spring (yes, meteorologically Spring begins March 1) day across the state. Temps running 15-25 degrees above seasonal norms with some record temps possible. Denver currently at 76 degrees which ties the record high for the date, and will likely break the record later this afternoon. Monday looks pretty similar with temps slightly cooler, although well above seasonal norms. Some gusty west to southwest winds may develop tonight into Monday afternoon causing some fire weather concerns in areas without snow as RH values expected to be below 15% many areas. Models indicate a weak cold front will move into eastern CO late Monday afternoon or evening, with northeast surface winds that will increase low clouds along the Urban Corridor and into the foothills by Monday night. Currenty looks like snow level will be in the 9000-10,000 ft range Monday night into Tuesday morning, so not expecting any snow issues. Most likely outcome will be some fog and/or light drizzle Monday night into Tuesday morning. Conditions should gradually clear by Tuesday afternoon and evening.

Now onto the potential precip for later this week. Models remain fairly consistent in the pattern, split in upper flow with one upper trough over CA that moves east by mid week, and another upper trough from the northern Rockies that moves south over CO on Thursday. With this pattern, precip is expected to move into western CO during the day on Wednesday, spreading east to about the I-25 corridor by Wednesday evening. Snow level looks to be 9000-10,000 ft on Wednesday. Precip persists Wednesday night into Thursday morning with snow level lowering to 8000-9000 ft. Showers likely to persist during the day on Thursday with snow level lingering around 8000 ft. Systems are weak and somewhat disorganized, so precip is likely to be intermittent and showery in nature. Precip amounts from models are still looking at near 1 inch of liquid equivalent across the foothills. The issue will be warm temps and high snow levels will limit accumulations below 8000-9000 ft, so would not expect big travel issues this week. Higher foothill elevations could see 4-8 inches of snow from Wednesday into Friday morning but mostly on grassy surfaces. Conditions should clear out by Friday morning with temps returning to near or above seasonal norms Friday.

For the coming weekend, models suggest a back door cold front may push into eastern CO from the Central Plains bringing temps closer to seasonal norms, and may see some low clouds from the foothills east on Saturday. Sunday we could see some showers in the High Country, but overall a decent weekend for March.

Beyond that, models suggest fair weather early next week, then a chance for precip from a potentially vigerous system mid to late next week that would have much colder air and lower snow levels.

_________________
"Climatology is what you expect, Weather is what you get".

"It is better to be roughly right than precisely wrong".

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Precip has mostly moved south of the Palmer Divide and gradual clearing will continue this afternoon. A nice 4 inches of moisture laden snow fell on Conifer Mountain overnight, with snow level remaining around 8000 ft.

CO is in store for a beautiful Spring weekend with mostly sunny skies and temps from 10 to 20 degrees above seasonal norms. Sunday will be slightly warmer than Saturday, but some breezy westerly winds may develop Sunday afternoon.

For next week, models have been going through daily, if not run to run, gyrations. Latest consensus appears to be that upper ridge will remain in place early next week, and divert Pacific system to our north. Only a weak cold front will make it's way across eastern CO Monday night, but latest models keep CO dry, with slightly cooler temps on Tuesday. For mid to late next week, a complex pattern emerges that models are still struggling with. In general terms, upper level trough develops over central CA Wednesday which advects some sub-tropical moisture into CO. Another upper trough moves southeast from the northern Rockies Thursday into Friday which will bring a cold front south across CO. Neither of these systems is overly impressive looking. At the surface, precip moves into western CO during the day on Wednesday associated with upper trough over CA. Snow level will be in the 9000-10,000 ft range. Wednesday night precip is expected to move into eastern CO with snow level lowering to 7000-8000 ft. Precip persists across most of CO Thursday as effects of the two systems combine over CO, with snow level remaining in the 7000-8000 ft range. Precip continues Thursday night with snow level lowering to near 5500-6500 ft. Precip should move out of the area by Friday morning with gradual clearing on Friday. Snowfall amounts very difficult to figure at this point. Models still suggest from 0.5 to 1.5 inches of liquid equivalent will be possible with this event, so using Spring conversion of 12:1 sow to water ratio, some areas above 8000 ft could be looking at 6-18 inches of snow. However, given the lack of strong dynamics my instinct is to suggest snow amounts towards the lower end of that spectrum at this time. Since this is also a warm system, snow will be of the wet and heavy variety, but with warmer temps this weekend and early next week, not sure how much if any would accumulate on primary roads. Will have to see how this unfolds next week.

Beyond that, models suggest more precip chances next Sunday into the following Tuesday, then clear things out until a more significant looking system could arrive late in the week into the weekend of March 27-29.

For those interested, it appears that CO has lost our place in the record books for the most snow in a 24 hour period. The record CO held was set on April 14-15 1921 near Silver Lake, CO (close to St. Mary's Glacier)where 86 inches were recorded over a 24 hour period. It is not yet official, but WMO representatives are investigating reports of 100.8 inches falling in Capracotta, Italy in just 18 hours on March 5. Capracotta is in the Apeninne Mountains that run through the center of Italy. Capracotta is east of Rome at an elevation of 4600 ft above sea level.

_________________
"Climatology is what you expect, Weather is what you get".

"It is better to be roughly right than precisely wrong".

Bump for 3/15 Update

Bump for 3/17 update

Bump for 3/18 update

Bump for 3/18 afternoon update