wxgeek's weather-Weather Outlook April 11-17

Another beautiful day across the state today. Weak cold front from the north will back door and stall over the eastern Plains this evening, which will lead to cooler temps, southeast winds and low clouds over the Plains east of a line from about Ft. Morgan to Limon. We will also see an increase in mid level moisture being advected from the south into south central CO that will lead to a chance for afternoon and evening showers with a slight chance for an isolated thunderstorm Tuesday. Best chances will be in the foothills and Palmer Divide. Wednesday looks similar to Teusday with southeast flow and low clouds over the eastern Plains, and a slight chance for an afternoon/evening shower or thunderstorm.

Weak upper trough from the west coast will move west and north of CO Wednesday night into Thursday. Major impact will be southwest flow increasing Wednesday night into Thursday with this system, so fire danger increases Wednesday night into Thursday. Foothills will see south to southwest winds of 15-35 mph Wednesday night and Thursday. Associated cold front moves across the state Thursday afternoon so temps cool some on Friday, with some moisture moving into western CO west of the Divide with snow level 7000-8000 ft. East of the Divide a cool and dry day on Friday.

Big change in the weather pattern looming for this coming weekend and early next week. Models still going through their normal iterations on the track of the upcoming system, but the general concensus at this time is to bring a large and deep upper trough from the west coast into the Great Basin/ Desert Southwest on Saturday and move the system slowly east across NM and CO SUnday into Monday. Definitely cooler temps, more clouds and the chance for precip returns this weekend into early next week. Timing and track of the system will determine our actual weather, but right now would plan for the possibility of a Spring snowstorm for the foothills Sunday and Monday. Snow level looks to be somewhere between 5500 and 7000 ft, so hard to tell if snow will impact the Urban Corridor, but looks pretty likely in the foothills. Since this system looks likely to develop into a cutoff low, forecast is also likely to change several times this week before models get a better handle on things.
_________________
"Climatology is what you expect, Weather is what you get".

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

Wed Apr 11

Good chance for afternoon and evening showers and isolated thunderstorms today. Best convergence area appears to be along the foothills initially where southeast flow from the Plains meets southwest flow over the mountains. This convergence area likely to move east over the Urban Corridor and Plains later this evening and tonight as upper trough passes. I currently don't see a good shear profile so don't think the chance for severe thuderstorms is very high, although we could see some hail from stronger cells. Unfortunately unless you are right under one of these showers/storms, not much overall precip to ease fire concerns, and any lightning from thunderstorms could spark new fires.

Southwest winds should pick up tonight into Thursday as upper trough moves east, so fire danger will raise Thursday with low TH values expected and stronger winds. Any precip Thursday looks to be confined to the higher mountains west of the Divide. Associated cold front will cool temps slightly on Friday with showers confined to the central and northern mountains with snow level 7000-8000 ft.

Attention then turns to system for this weekend. General concensus of models is that a deep upper trough with a closed circulation will move from the Pacific coast to near the CA/VN/AZ border area on Saturday. This will bring precip into western CO west of the Divide Friday night into Saturday, with snow level 6500-7500 ft. Upper trough is forecast to move across CO on Sunday with a surface low developing over northeast CO and drags a cold front through the foothills Saturday night. This track keep the majority of precip west of the Divide and north of I-70. If the upper trough/low tracks farther south, better precip chances for areas south of I-70. Even with the current forecast track, precip chances look good for the foothills and Urban Corridor Sunday into Monday morning. Snow level currently looks to set up between 5500-6500 ft, so questionable how much snow would accumulate in the Urban Corridor, but above 7000 ft accumulating snow looks like a good bet. Right now, best guess is only a few inches, maybe 2-5 in favored areas, and 1-3 in less favored areas from Saturday night through Monday afternoon. However, if the track of the system changes, then snow amounts would change. More southern track and we see more snow, if the system tracks farther north or faster, less snow. This system will also likely have convective elements to it, so areas that have convective showers could receive a very quick -2 inches of snow, or rain with hail at lower elevations. The bottom line is to expect much cooler temps and unsettled weather Saturday through Monday with some much needed precipitation likely.

Tuesday through Wednesday next week look mild and dry, and then models indicate another upper trough to move through CO late next week, so precip chances for Thursday into Saturday.
_________________
"Climatology is what you expect, Weather is what you get".

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