wxgeek's weather-Weather Outlook Feb 8-18-Update 2/12

Update Fri Feb 13

Sunny and unseasonably warm statewide today with temps running 10-15 degrees above seasonal norms thanks to the upper ridge dominating weather across the western U.S. We should see even warmer temps and sunny skies on Saturday.

Models now suggest two distinct systems will affect CO weather Sunday and Monday. The first system will slide down Sunday and bring precip to northern CO, mostly north of I-70 but some precip may slide as far south as the Palmer Divide. Precip will begin Sunday morning with snow level around 6000 ft then diminish by Sunday evening. Northern and central mountains could see 1-3 inches of snow, while foothill and Urban Corridor areas likely to see less than 1 inch of accumulation, and with warm temps this week roads likely to remain wet. Next and stronger system will move south into CO on Monday. Precip will move south into northern CO late Sunday night and spread south during the day on Monday. This system will feature colder air and more precip. Precip will remain north of I-70 overnight, but move south of I-70 by dawn, just in time to mess up the morning commute. This system will be all snow, but only impact areas east of the Divide. Could see some moderate snowfall at times Monday morning, with snow diminishing by afternoon. Mountains east of the Divide could see 3-7 inches of snow, with foothills and Palmer Divide seeing 2-6 inches. Urban Corridor and plains could see 1-3 inches, with areas on the west and south side seeing highest amounts. Roads should be better by evening commute, but could still be some slick spots. Precip moves out by evening.

Latest models do not bring arctic air into eastern CO with this system now, so temps will be below seasonal norms Monday and Tuesday, but not the frigid arctic temps. Tuesday through Friday will be dry statewide with temps climbing to slightly above seasonal norms Wednesday through Friday next week. Next precip chances will be next weekend. Models a bit uncertain with how this system evolves, but still looks like decent chance for more precip next Saturday and Sunday.

Beyond that, models struggling to find a solution. Latest GFS runs keep upper ridge along the west coast and keep CO under northwest flow aloft, near the border of warm air to our west and cold air to our east. So last week of February could see cold arctic temps with some snow, or remain dry and mild, too early to tell which way things will go.

Across the eastern U.S. there is no doubt which way things will go. Poor souls in this area will continue to see very cold temps and lots of snow through the end of February. For the weekend, major winter storm will impact the Northeast. Snow moves into the eastern U.S. from the Mason-Dixon line northward during the day on Saturday. Generally light amounts for most areas. New England will be different. Saturday night into Sunday system undergoes extreme cyclogenesis with a 964 mb surface low (similar to a category 2 hurricane) forming off the Maine coast. This will bring very heavy snow to coastal areas of New England and surface winds of 35-60 mph, and some gusts in the 70-100 mph range. This will become a winter hurricane that features a 70 mb pressure gradient from the Great Lakes to New England. Needless to say, travel will come to a halt in most areas of New England on Sunday into Monday. Next week will see more snow and cold for the eastern U.S. with this pattern persisting into early March according to long range models. A forecaster in the NWS Boston office referred to the system this weekend undergoing "bombogenesis".

_________________
"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 Feb 12

Mild and dry day statewide today under partly cloudy skies. This pattern looks to persist through Sunday with temps well above seasonal norms as upper ridge dominates the weather pattern over the western U.S. Meanwhile, snow and cold persist across the Northeast U.S. under the influence of upper trough. Another potent winter storm is poised to move over the Northeast this weekend, with heavy snow and very strong winds creating blizzard conditions from Saturday into Sunday night. Expect travel disruptions over the Northeast this weekend that could linger into early next week. Residents in this region are likely not fond of ground hogs right now.

Models continue to suggest the upper ridge over the western U.S. will move west over the weekend into the eastern Pacific early next week. This will allow a system to move over CO from the northwest. Latest models bring precip into northern CO late Sunday night, then move south across most of CO during the day on Monday. Heaviest snow looks likely to be over the foothills and mountains east of the Divide south of I-70, similar to our system this week. For snow amounts, currently looks like 2-6 inches possible for the foothills and Palmer Divide, 1-4 inches for the Urban Corridor, and up to 12 inches for the central and southern mountains. These amounts are preliminary and could change either way based on future model runs. Arctic air will move into CO Monday night into Tuesday, so expect some very cold temps Monday into Tuesday. Latest models bring snow to an end Monday evening, with only some light flurries and lingering low clouds on Tuesday.

Warmer and dry conditions move back over CO next Wednesday through Friday. Next chance for precip will be next weekend. Models are currently vacillating between keeping upper ridge in the eastern Pacific beyond next week and allowing cold systems to move over CO, versus creating a blocking upper ridge over Alaska and allowing warmer and moist Pacific systems to move into the West Coast and then into CO. Either way, CO looks to receive continued precip chances through the end of the month, it will be temps that could vary.

Looking at longer term climate predictions, the latest ENSO update keeps the 3 month ONI average at 0.7, so our weak El Nino continues. However, the trend is for cooling in the equatorial eastern Pacific, so conditions in the Nino 3.4 region look to be cooling, yet some very warm water remains between Hawaii and Baja California, so a bit of an unusual El Nino pattern. Meanwhile, the positive MJO that was over the western U.S. in December, turned to a negative MJO during January and February, which accounts for our drier than usual pattern. A new positive MJO is entering the central Pacific and should be over the western U.S. during sometime in March and April, so we may still be poised for some abundant moisture in March and April if this pans out. The Climate Prediction Center is also predicting above average precip over much of the western U.S. from March through May. So keep your hopes alive we will have a snowy March and April that will keep our fire danger lower as we enter May and June.

_________________
"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 Wed Fab 11

Nice shot of snow last night. It appears the NAM model was correct, but sometimes hard to go with the outlier. Mostly sunny today as system moves out with temps near seasonal norms.

For Thursday through Sunday, upper ridge will build back in and warm temps above seasonal norms under mostly sunny skies statewide. Temps Saturday may be close to record levels in some areas.

The good news is that medium range models are suggesting a significant pattern change to take place early next week and persist into late February. The dominant upper ridge is forecast to retrograde westward into the eastern Pacific, which will allow systems to move down into CO from the northwest. First system will move into CO late Sunday night with precip moving into western CO overnight, then moving into eastern CO Monday into Tuesday. Foothills and plains could see significant snowfall Monday. Second surge is forecast to bring arctic air and some light snow to eastern CO on Tuesday, so temps well below seasonal norms. Arctic air will remain in place Wednesday under mostly sunny skies.

Dry conditions with temps near seasonal norms expected next Thursday and Friday. By next Saturday, a potentially significant winter system could move into CO and remain in place through Monday, which could bring significant snowfall to much of CO. Will have to wait and see what transpires. More systems may follow if models are correct, which could provide some much needed snowfall through the end of February.

_________________
"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 Tue Feb 10

Nice start to the day with some snow in the High Country and showers spilling into the western foothills. This activity should dissipate this afternoon. Then, by evening upper level trough will pass over CO and bring good chances for precip to the mountains, foothills and western plains mostly south of I-70. Cold front will cool temps and upslope flow will develop by this evening. Snow level will begin around 6000-7000 ft so initial precip will likely fall as rain in the Urban Corridor. Snow level will lower to plains level by midnight. Precip becomes likely between 5 pm and 8 pm, and will persist into early Wednesday morning, with the potential for some moderate to heavy snow at times tonight. For snow amounts, tough forecast. Models are all over the place, with NAM showing potential for heavy amounts, while GFS, Euro and WRF have lesser amounts. All models agree heavy snow is likely south of the Palmer Divide, especially across southern CO and over the Sangre de Cristo mountains where a Winter Storm Warning has been issued. For local foothills, believe 1-3 inches will cover most areas south of I-70, but potential for up to 6 inches exists for areas of the foothills, especially farther south. Snow should end from north to south by 3am to 6 am, but morning commute could be slick and slow. For the Urban Corridor, 1/2 to 2 inches possible mostly south of I-70, but up to 4 inches possible over the Palmer Divide and farther south. Mostly sunny skies will prevail Wednesday with temps near seasonal norms. Lots of melting so commute home should be fine.

Thursday though Sunday looks dry statewide with temps rising back above seasonal norms. Next chance for precip will be Monday into Tuesday with much colder temps according to models. Snow amounts could be several inches at this time. Then dry and mild looks to come back next week Wednesday through Friday, then next chance for precip 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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Nice to be back in CO once again, but what a wonderful trip to Costa Rica to celebrate my wife's birthday. Such a beautiful place with lovely people.

Now on to the weather. Windy and warm day ahead for CO with temps 10-20 degrees above seasonal norms. Westerly winds will subside some during the day but remain gusty at times, keeping heightened fire danger for areas absent of snow. Monday looks to be very similar to today with breezy and warm conditions statewide. Dominant upper level ridge over the western U.S. is responsible for our warm and dry weather, which has also kept the eastern U.S. cold and snowy as a large upper trough remains over the eastern U.S. More heavy snow for the Northeast today into Monday which could cause travel delays.

Change this week will happen Tuesday night into Wednesday afternoon as a weak upper level trough moves through the upper ridge. This will bring a chance for precip to central and eastern CO with snow level 6000-7000 ft Tuesday night lowering to 5000-6000 ft Wednesday morning. Currently looks like any snow amounts will remain on the light side, with perhaps 1/2 to 2 inches possible for the foothills and adjacent plains. Mountains could see a bit more, so the Wednesday morning commute could be a little slick and slower than usual.

Upper ridge builds back in Thursday and will keep CO dry with temps above seasonal norms Thursday into the weekend. Next chance for precip looks to be the middle of next week.

In general, current pattern will keep snowfall below average and temps above average. Unless we see a significant pattern shift later in February, could be yet another drier than average month for snowfall. Our seasonal snowfall currently stands at 49 inches for Conifer Mountain, which is well below our average of 70 inches through the end of January. With February currently looking below average, we are putting a lot of pressure on above average snowfall in March and April, which are the two snowiest months of the year on average. Not quite time to panic yet, as recent dry early starts to the year have ended with lots of moisture in the Spring and Summer, but we all know if the dryness continues we could see a difficult fire season ahead, so always best to be prepared.

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

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

Bump for 2/10 update

Bump for 2/11 update

Bump for 2/12 update

Bump for 2/13 update