wxgeek's weather-Mothers Day Snowstorm - Update 5/12

Update Mon May 12

Impressive snowstorm for eastern CO, especially for May. Snow reports from NWS show foothills north of I-70 received 10-28 inches, while south of I-70 areas received 10-20 inches. Metro area shows mostly 3-8 inch totals. Records also show the biggest snow event in May since 1993 was 18.5 inches in 1995, so it appears this will become the biggest May snow event since records on Conifer Mountain began in 1993. Also became our biggest snowstorm of the season, and has gone a long way in providing moisture and keeping fire danger down for a while.

Snow is winding down across most of CO with some lingering snow along the foothills, Urban Corridor and south central mountains. Conditions should improve through the afternoon most areas, although models show some additional accumulation expected across southwest and south central CO this afternoon and evening. Freeze Warning has been issued for most of eastern CO for tonight into Tuesday morning as temps expected in the mid to upper 20's, lower in the foothills. Tuesday will have slightly warmer temps, but still well below seasonal norms under partly cloudy skies. Some flurries possible mostly along and west of the Divide in the afternoon, with snow level 6000-7000 ft. Wednesday should see mostly sunny skies after another cool start, with only isolated afternoon showers over the High Country.

By Thursday, temps expected to warm back to near seasonal norms, but better chances for afternoon and evening showers from the mountains into the foothills and Urban Corridor and plains, with snow level 9000-10,000 ft. Isolated thunderstorms also possible. Friday will see even warmer temps as upper ridge builds back over the Great Basin. Scattered afternoon showers and isolated thunderstorms possible Friday into Friday evening, with snow level above 10,000 ft, but small hail will be possible in thunderstorms.

For the weekend, mostly dry and warm conditions expected statewide, with temps climbing above seasonal norms, and low 80's possible on the plains Sunday. Fair and warm weather expected to continue into early next week. By next Wednesday an upper trough will replace the upper ridge in the Great Basin, and will import moisture and instability into CO, which will increase chances for showers and thunderstorms from Wednesday into Friday, then drier and warmer weather expected to return for the following weekend.

With this past snow, season total at my home on Conifer Mountain increased to 126 inches. Better, but still well below the seasonal average of 170 inches and 74% of our seasonal average.

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

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

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Update Sun May 11

Heavy snow across northern CO overnight beginning to move south. Up to 12 inches reported overnight in the foothills of Larimer county. Banded precip associated with jetsream aloft will move south of I-70 this afternoon and evening, so heaviest snow for local foothills will be from Noon through midnight. Upper level low currently over southern UT and will move into southwest CO this evening, then fill (weaken) and move across eastern CO tonight as an open trough. Precip has turned to mostly snow across the Urban Corridor, but roads currently mostly wet below 8000 ft. As temps drop during the day and heavier snow moves in, expect most roads to become snow and ice packed later this afternoon and remain that way through Monday morning. Expect very slick roads as wet pavement turns to ice underneath snow. Models predict snow to persist across most of CO through Monday morning, tapering off by around noon, with flurries persistsing in the mountains through Monday evening. This will translate into a rough morning commute, so allow some extra time. Models consistent in snow amounts, so above amounts still look good. Currently about 3 inches on Conifer Mountain, so 8-14 by morning looks good, with the potential for up to 16 inches locally. Snow of the wet and heavy Spring variety.

Hopefully everyone has found their own way to combine Mothers Day with a nice Spring snowstorm. Lots of House of Cards in my future today.

After conditions clear Monday afternoon, temps will remain well below seaosnal norms through Wednesday. Dry conditions still expected with a few isolated showers later in the week. Temps return to seasonal norms late this week with dry and warm weather expected into the coming 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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Update Sat May 10

Showers and isolated thunderstorms moving across CO this afternoon. Snow level above 10,000 ft today.

Attention turns to incoming system. General trend in models has been to slow the system down. Latest runs have upper trough that is currently moving into the Pacific Northwest becoming a closed upper low over southern UT on Sunday morning, and moving into soutwhest CO by Sunday evening, then into eastern CO Monday morning. This translates into a later start to precip, and later end. Hence, showers this afternoon will die down after sunset. Precip associated with incoming system will move into western CO tonight and move into the northern foothills north of I-70 overnight. Snow level tonight will be near 8000 ft west of the Divide and 9000 ft east. By Sunday morning, surface low will be over southeast CO and cold front will begin to move south from WY. Precip looks to move south of I-70 after sunrise Sunday morning and will move south during the day, becoming moderate to heavy at times. Precip continues in the mountains all day Sunday. Snow level 6 am Sunday is expected to be around 8000 ft, and will lower during the day, down to around 6000 ft by 6 pm Sunday. Precip is expected to persist Sunday night into Monday morning now, ending by around Noon on Monday. Snow level will lower to plains level Sunday night.

For snow amounts, not an easy call. Models have lowered overall precip amounts slightly, but still robust between 0.75 and 1.5 inches most areas, near 2 inches over mountains. Thus, still see 1-2 feet of snow in the central and northern mountains, with highest amounts north of I-70. Southwest mountains will see 8-16 inches. For the foothills, still think 8-16 inches is a good range above 8000 ft, with highest amounts north of I-70 where local accumulations up to 2 feet will be possible. For areas around Conifer, think 8-14 inches more likely. For areas below 8000 ft, amounts likely to be slightly lower due to initial melting of snow Sunday morning and warmer initial temps. For the Urban Corridor, snow will not likely accumulate until late Sunday afternoon into Monday morning, thus amounts of 3-7 inches still seem reasonable, with 1-4 inches possible farther east on the plains. No matter how you look at it, a pretty impressive storm for mid May.

With the heavy wet snow, power outages will be likely. Northerly winds will accompany system on Sunday with speeds of 15-35 mph possible, which will reduce visibility and cause near whiteout conditions at times. In general, travel will be tough on Sunday, and become more difficult Sunday evening and night as temps drop and roads more likely to become snow and ice packed. Monday morning commute could be pretty ugly with snow and ice packed roads all the way into the Urban Corridor. Expect roads to be in preytty good shape for the evening commute.

For the rest of the week, dry conditions expected through next weekend, with only a few isolated showers possible late in the week. Temps will remain below seasonal norms Monday through Wednesday, then climb back to near seaosnal norms late in the week, and above seaosnal norms by next weekend.

Despite the weather, I hope everyone is able to still enjoy Mothers Day, and I hope all the Mom's are treated with the love and admiration they deserve.

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

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

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Mothers day forecast

After a brief taste of winter this week, mother nature is preparing a special event for Mothers Day. Perhaps Ma Natures children have not been so attentive this past year, so she has some venting to do.

Prior to that, more showers will develop this afternoon and evening, mostly across the mountains, but some may move into the foothills and Urban Corridor. Snow level looks to be around 9000 ft today, so a dusting and small hail all possible in showers, with a few isolated thunderstorms. Activity should die down after sunset.

Saturday will start out nice, then clouds increase from the west in the afternoon. Vigorous upper level trough will move from the Pacific Northwest into the Great Basin on Saturday, and then will move across southern CO on Sunday. Precip band will develop across western CO Saturday afternoon and evening, and move into northern and central CO Saturday night. As upper low and surface low move across southern CO Sunday, precip will become widespread Sunday across the entire state. Snow level will begin high Saturday afternoon, around 10,000 ft lowering to near 8000 ft by midnight, then down to around 6000 ft by Sunday morning. Snow level on Sunday expected to remain in the 5000-6000 ft range lowering to plains level by Sunday afternoon and night. Models are in good agreement on the track of the system, but precip amounts differ some. NAM has the highest precip amounts of nearly 2 inches of liquid equivalent across the Front Range, while the GFS has about 1 inch while the WRF between 1 and 2 inches. This will translate into a very wet and snowy period from Saturday night into early Monday morning. NWS has issued a Winter Storm Watch from Sunday morning through Monday morning for the mountains and areas above 6000 ft in the Metro Area and foothills. Models point to highest precip in the northern foothills, but all areas north of the Palmer Divide could see significant snowfall. So here is my snow amount forecast:

Mountains: 10-20 inches
Foothills and Palmer Divide: 8-16 inches (heaviest above 8000 ft and north of I-70)
Urban Corridor: 3-8 inches (heaviest on west and south side of town above 6000 ft)
Plains: 1-3 inches

Very hard to determine when snow will stick to paved roads. Initial snow likely to melt, but very heavy snow overnight Saturday could create slush and snow for Sunday morning. With daytime warmth, snow on roads may melt, but with moderate to heavy snow most of the day Sunday, snow may pile up on roads, especially above 7000-8000 ft, so driving may be difficult to get around Sunday in the foothills. By Sunday evening, roads very likely to become snow and ice packed and remain that way into the Monday morning commute. Snow looks to end sometime between midnight and 6 am Monday. This system will likely produce our biggest snowfall of the season, kind of ironic it has waited until now for our biggest dump, but this will provide some excellent moisture to keep fire danger low for a week or two in a critical fire month.

Because snow will be of the wet and heavy variety, this system also has the potential to create widespread power outages, so foothill residents may want to take precautionary power outage action Saturday.

Weather will return to dry and warmer Monday through Wednesday, with some showers possible Thursday and Friday next week, with snow level 8500-9500 ft.

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

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

Bump for 5/10 Update

Bump for Sunday 5/11 update

Bump for 5/12 update