wxgeek's weather-Nice Wknd, Big Snow next wk-Update 4/5

Update Sat Apr 6

Partly to mostly cloudy today as weak upper level disturbance approaches CO. Showers will develop this afternoon into this evening with snow level around 10,000 ft. Best chances will be across the High Country. As disturbance passes ocer CO tonight, some showers will be possible overnight into early Sunday morning with snow level lowering to near 9000 ft. Showers will re-develop Sunday afternoon and evening, mostly across the High Country once again with snow level around 10,000 ft.

So, another day and even less certainty regarding our upcoming storm. The only model that has remained consistent in the ECMWF, which tracks the upper low into the 4 Corners region Tuesday morning and moves it very slowly across southern CO. The WRF is somewhat similar to the Euro model, while the latest NAM and GFS models track the upper low to near the 4 Corners late Monday night then move the low rapidly northeast into northeast CO by Tuesday afternoon. The GFS anmd NAM solution would greatly limit snowfall in the foothills as the surface low moves too far north in response to the upper low tracking so far north. Liquid precip totals down to less than 0.5 inches with the latest GFS run, which would limit snow to 4-6 inches across the foothills. Heavy snow would move farther north into eastern WY and western SD/NE. However, the Euro models remains consistent for what that is worth, and would bring at least a foot of snow to most foothills areas from Monday night into Wednesday morning. My gut is still sticking with the Euro and close to a foot of snow, but the modelrama of wildly varying solutions is adding uncertainty into the forecast. At this point, we could see as little as 3 inches of snow or up to 18 inches, not a good range for planning I understand. Hopefully as the system begins to move onto the West Coast Sunday, models will get a better handle on things.

The remainder of next week still looking mostly dry, with some mountain showers possoible Thursday, otherwise 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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Update Fri Apr 5

Mostly coudy and warm today with mid and high clouds associated with a weak upper level trough moving across the state today. Some showers currently moving through the High Country,a nd some may drift across the foothills this afternoon and evening, but not much precip if any at all east of the Divide. Fortunately strong westerly winds have not materialized, but could pick up later this evening and tonight still.

Saturday should be mostly sunny to start, with some isolated showers mostly across the High Country in the afternoon and evening. Slight chance some could drift east across the foothills. Second upper level disturbance moves across Saturday night so some overnight showers possible over the High Country and foothills into early Sunday morning. Sunday will be partly to mostly cloudy with increased chances for showers in the afteroon and evening with isolated thundrestorms possible. Snow level the entire weekend around 10,000 ft, perhaps lowering to around 9000 ft Saturday night into early Sunday morning.

Spring storms are never easy to forecast, and the one for next week is being very uncooperative. Model solution are still all over the board, with the latest GFS runs moving the system through more as an open trough and much faster. Currently discounting the GFS solution, while the ECMWF, NAM, WRF and UKMET models in decent agreement. However, even within the ECMWF ensemble there are big differences, so forecast uncertainty is pretty high with this system right now. General concensus still has the upper level trough digging to neat the 4 Corners region by Monday night/Tuesday morning, then moving east across the CO/NM border with a deep surface low forming over the TX panhandle Monday night into Tuesday. If this scenario holds true, we would see good snow amounts for eastern CO from Monday night into Tuesday night. If the faster and more northern GFS solution is correct, snow amounts would be much lighter. I am still favoring the deeper and slower solution for now, so I still thinks we will see at least a foot of snow for most foothills areas, with the potential for more. If the slower and deeper solution is correct, snow level would begin high on Monday afternoon, around 10,000 ft, but lower quickly to near plains level by Tuesday morning and snow pretty hard most of the day Tuesday across all of eastern CO, with snow letting up by Wednesday morning. Will have to monoitor how the models converge over the weekend before any confidence can be garnered. Still best to prepare for the worst at this point.

_________________
"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 Thu Apr 4

Beautiful day across the state today, mostly sunny skies and temps above seasonal norms. The Spring "Green Up" is in full force below 6000 ft, and will gradually be working to higher elevations through April and May. Even warmer temps on tap for Friday, although strong west to southwest winds are expected to develop Friday afternoon into Friday night. This has prompted a Fire Weather Watch for areas of southern CO. Some showers will develop along a weak cold front Friday afternoon and evening, mostly over the High Country, but some showers could persist into the foothills and Urban Corridor. Snow level will be above 10,000 ft, so liquid precip for most areas. Slightly cooler temps on Saturday in the wake of the cold front, but a nice day with temps near seasonal norms and light winds. Isolated showers in the afternoon possible mostly over the south central mountains. Another weak system moves into CO Saturday night into Sunday morning bringing better chances for precip, especially across the mountains west of the Divide. Snow level 7000-8000 ft Saturday night, so mountains could see a few inches of snow overnight. Some showers possible across the foothills and Urban Corridor Saturday night into Sunday morning with snow level around 8000 ft. Showers expected to re-develop Sunday afternoon and evening with most activity over the High Country, but isolated showers possible over the foothills and plains with snow level around 9000 ft.

Then we will deal with a much more potent system early next week. Models still vacillating, but latest runs in slightly better agreement. Latest GFS would bring a vigorous upper trough from the Gulf of Alaska and dig it into the Great Basin on Monday, then develop a closed upper level circulation near the 4 Corners region by Tuesday morning, then move it to east central CO by Tuesday evening and east of CO by Wednesday morning. This scenario, if true, would bring heavy precip to much of CO Monday and Tuesday. Precip would move into western CO during the day on Monday with snow level around 9000-10,000 ft, and spread east into the foothills and plains by Monday night with snow level lowering to near plains level by Tuesday morning. Snow could be heavy at times Tuesday across all of CO and persist into Wednesday morning in eastern CO. Latest liquid precip totals are once again in the 1-2 inch range across the foothills, so doing the math with around a 12 inches of snow to 1 inch of water ratio (Spring ratio), you get the picture. Still too far off to make this a certainty, but getting close enough for residents to become prepared for this type of event, if you are not already.

the remainder of next week looks dry and mild with a few mountains showers. The following week has potential fire weather concerns, so getting more moisture will help reduce the fire threat.

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

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

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System yesterday did not live up to model expectations, but at this point we'll take any and all moisture. Fair and mild weather expected today through Friday as short wave upper ridge builds across CO, except for some isolated showers this afternoon and evening, mostly over the High Country with snow level 8000-9000 ft. Temps on Friday will be some 10-15 degrees above seasonal norms. As the upper ridge moves east, we will see some weak disturbances in westerly flow aloft pass over CO this weekend. This will lower temps slightly, and lead to a chance for afternoon and evening showers this weekend. Majority of any precip will be from the foothills west, with only slight chances for precip east of the foothills. Snow level will be at or above 10,000 ft mostly, and isolated thunderstorms will be possible each day.

Attention then turns to a possibly significant Spring storm early next week. Models are vascilating wildly from run to run with the track and intensity of the upper low/trough. General concensus is that a fairly deep upper level trough will move from the Pacific Northwest into the central/southern Rockies Monday into Tuesday. Some model runs have had a deep closed low that hangs over the area through Wednesday, while other runs have a much less impressive upper trough move through rather quickly. Thus, liquid precip amounts have ranged from 2-3 inches to 0.5 inches the past few days. Hard to tell which way this will end up. I tend to favor slower and deeper solutions this time of year, but that is not how it always evolves. Bottom line at this point is to expect colder temps and some precip at least Monday into Tuesday. How much precip will have to wait for now. Initial snow level looks to start out high Monday, in the 9000 - 10,000 ft range, but lower to near plains level by Tuesday morning. Precip could end as early as Tuesday afternoon, or persist into Wednesday morning. After that, models indicate dry and mild weather for late next week into next weekend.

In other worldwide news, parts of Argentina were hit with serious flooding the past 2 days. Areas near Buenos Aires received up to 16 inches of rain in 24 hours. That is more precip than we normally receive all year, and it came in a 24 hour period over a heavily populated urban area. Needless to say, serious flooding that resulted in loss of lives and property occurred.

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

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

Bump for April 4 update

Bump for 4/5 Update

Bump for 4/6 Update