wxgeek's weather-Dry, Mild & Breezy then?-Update 12/17

Update Tue Dec 17

Near record warmth is gracing much of CO this week while wildfire is spreading in CA, not usual stuff in mid December. Another warm and breezy day on tap before some cooler weather makes it's way into CO later this week. Upper level trough forecast to dig down the west coast Wednesday into Thursday before turning east into northern Mexico on Friday, then across the southern Plains Saturday and into the Ohio Valley Sunday. For CO, this is not an optimum track for snow, but as northern branch of the upper trough moves across there will be enough moisture and lift to provide some snow to the mountains. Latest models call for snow to move into western CO late Wednesday night into Thursday morning, then a cold front moves south across eastern CO Thursday night. Not much snow expected with the cold front for eastern CO, maybe a few flurries but not much more expected east of the Divide. Some light snow is possible west of the Divide Friday into Saturday as southern upper trough moves by to our south. Temps will be back closer to seasonal norms Friday through Sunday.

For next week, it should start off warm, dry and breezy Monday and Tuesday. For mid to late week, a weak upper level system will move down from western Canada and may bring some light snow to CO Wednesday into Thursday with cooler temps. Not much snow expected with this system. Models keep weak systems moving by in northwest flow aloft that could bring some light snow to mostly western CO into next weekend.

For those traveling, the above mentioned systems will bring snow to the Great Lakes and Northeast Thursday and Friday. The southern branch system will bring mostly rain to the southern plains and lower Mississippi Valley late Friday into Saturday, with the chance for some severe thunderstorms. This system will gather strength as it moves northeast Saturday and Sunday into the Ohio Valley, Great Lakes and Northeast. Snow looks to be confined to northern areas of the Great Lakes. Biggest travel disruptions look to be Chicago and northeast airports on Sunday. Conditions should clear out Monday. Great Lakes remain cold with some snow next week, otherwise no big travel issues expected.

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

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

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Sun Dec 15

Sunday through Thursday will feature dry weather across the state, with temps some 10-20 degrees above seasonal norms, and some windy periods. Westerly winds of 20-45 mph possible at times in the foothills from Sunday into Thursday. No precip is expected anywhere in the state during this period.

Models have changed the solution for the next upstream system. GFS and ECMWF are in good agreement that an upper trough will move south from western Canada later this week. Models split the energy into a northern and southern branch, which will diminish the impact from this system. Northern branch will move across the northern Rockies and northern Plains Wednesday into Thursday. Southern branch will have an upper low dig along the west coast into southern CA Thursday then into northern Baja on Friday. This upper low will eventually track across northern Mexico and then along the Gulf Coast early next week.

The impact to CO will be minimal from this scenario. A cold front will move into northeast CO Thursday night and bring some light snow to areas mostly north of I-70. There will not be any arctic air with this system now, so temps will only cool to seasonal norms, and snow amounts only expected to be in the 1-2 inch range for areas north of I-70. Foothills may see a dusting, but likely no snow at all now. After this system, models indicate a dry northwest flow regime will be present the week of xmas, with perhaps some mountain flurries, but no real significant snow and temps back above seasonal norms. It appears very likely we will end December with below average snowfall, getting us further behind in our snowfall for the season.

The new model solution also changes the forecast for the eastern portion of the country. It now appears the northern upper trough will bring some snow to the Great Lakes, upper Ohio Valley and Northeast Thursday into Friday, but nothing too serious. Some minor travel delays possible. The southern upper trough will develop later, and impact the southern Plains and lower Mississippi Valley next Sunday into Monday with mostly rain. System will develop into a significant system on Monday into Tuesday affecting the Ohio Valley, mid Atlantic states and Northeast, but snow and ice look to remain farther north in the upper Ohio Valley and Northeast. System could impact travel in this region, but not as much as previously thought. Great Lakes and Northeast look to remain cold with mostly lake effect snow week of xmas while the western U.S. remain dry and mild under upper level ridge.

_________________
"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 Dec 13

Pretty tranquil weather across the state today. Some very light flurries possible from this afternoon into Saturday morning over the High Country, but nothing substantial. Temps slightly cooler today and Saturday, but still near seasonal norms. Dry and breezy weather expected Sunday into Monday as northwest winds aloft pick up and create some mountain wave conditions that will bring gusty west to northwest winds to the mountains and foothills from Sunday afternoon into Monday evening. Temps will remain above seasonal norms Sunday into next Thursday. As our next system approaches late next week, westerly winds expected to increase ahead of this system Wednesday night into Thursday.

Models beginning to come into decent agreement on the track and timing of our next arctic system. Arctic front associated with a deep upper level trough will push south through CO Thursday night, bringing snow to all of CO by Friday morning. Snow looks to persist during the day on Friday, diminishing by Saturday morning. Temps don't currently look to be as cold as our last arctic blast, but that could change. Snow amounts currently look moderate, in the few to several inch category, but nothing major. Of course, we are still quite a ways out so models could change between now and then. The week of xmas continues to look cool with chances for light snow again on xmas eve and xmas day, then dry and mild into the new year.

The more significant impact continues to be a major if not epic winter storm from the Southern Plains to the Great Lakes and everything east from next Friday into next Sunday. This could be one of the worst ice storms in recent history over the Mississippi Valley, Ohio Valley and Mid Atlantic region, combined with significant snow to the north and heavy rain and severe thunderstorms to the south. Travel likely to be severely impacted over a very large portion of the country. This could also really mess up last minute xmas deliveries by all postal and parcel carriers.

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

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

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Thu Dec 12

Another beautiful day across the state today with temps well above seasonal norms. Quite a change from a week ago when temps were struggling to get above zero. Dry and mild weather pattern should persist into the middle of next week, with some gusty westerly winds at times. Weak upper level system passes over CO Friday that will cool temps slightly back to seasonal norms into Saturday. By Sunday, upper ridge builds along the West Coast and will keep a brisk northwest flow aloft over CO that will insure dry weather and mild temps, but will also cause strong west to northwest winds at times along the mountains and foothills. Gusty winds will be possible at times from Sunday into Tuesday.

For late next week, models are beginning the merry-go-round of possible solutions. We have everything from a cut-off low dropping down the west coast, to a significant upslope storm over CO, to a system passing to our north and east for late next week. I personally feel the system will move down from the north into the Great Basin and provide a decent snow event for CO from Thursday night into Saturday morning with cold arctic air accompanying the system, but models could go either way at this point, so will have to wait and see what transpires. Should have a much better handle by early next week. Even with the wide range of possible solutions, the consensus is that much colder temps with some snow will impact CO late next week.

The other national impact from this system will be a travel nightmare as the system moves east from Friday into the following Monday. Models still project a two pronged wallop east of the Mississippi that will bring heavy rain, freezing rain and sleet, and snow to a large portion of the eastern third of our country during one of the busiest travel periods of the year. If you are planning travel eastward during this period, keep a close eye on things as travel could become difficult to impossible with ripples that could impact air travel across the entire country.

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

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

Bump for 12/13 update

Bump for 12/15 update

Bump for 12/17 Update