wxgeek's weather-Dry/Breezy, Precip wed/sun-Update 6/18

Update Wed Jun 18

Weak cold front has backed into northeast CO overnight, ushering in slightly cooler temps and easterly winds along with higher RH values. This front has washed out along the Palmer Divide this morning, and has just pushed up against the foothills. Farther west, weak cold front associated with upper level trough over the northern Rockies is just moving into western CO with some rain showers along front. As daytime heating destabilizes atmosphere, expect more showers and thunderstorms to develop along western cold front as it moves across CO this afternoon and evening. Limited moisture from the foothills west, so most showers/thunderstorms will be high based storms with dry lightning possible and gusty outflow winds. As this front works into the Urban Corridor, storms may intensify with better low level moisture, although storms are not expected to become severe. Precip amounts expected to be light due to limited moisture and fast moving nature of storms. Best precip chances will be east of I-25 later this afternoon and evening. Storm motion is expected to be from the west at 15-25 mph. All activity should exit the state by midnight. Temps expected to be near seasonal norms today.

Thursday through Saturday is expected to be mostly dry statewide. Temps will gradually warm from near seasonal norms Thursday to above Friday and Saturday. Very slight chances for isolated afternoon storms on Saturday, mostly east of I-25. Somewhat better precip chances will exist on Sunday from the Divide east, but activity expected to be isolated with slightly cooler temps, but still above seasonal norms.

For next week, isolated afternoon and evening showers and thunderstorms look to be possible Monday through Friday, with best chances from the Divide into the foothills. Precip amounts do not look terribly high, unless you happen to be directly underneath a strong shower, so pretty typical summertime pattern of diurnal convection as upper level ridge begins to build in earnest across the western U.S. As upper ridge builds, surface temps will climb to normal summertime values. With warmer temps and light precip amounts, ground fuels will continue to dry out through June into early July, so fire danger expected to be at highest levels of the season for the next few weeks, until the North American Monsoon begins. Hopefully we can escape any large fires for the next few weeks.

_________________
"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 Jun 17

Another warm and windy day across the state today. Southwest winds generally in the 20-50 mph range today with strongest winds in the mountains. RH values slightly higher than yesterday, but still below 20% most areas, so more fire weather concerns today, especially western and south central CO where Red Flag Warning in effect again today. Winds expected to remain gusty into this evening. Temps again 10-15 degrees above seasonal norms today. Farther north, Winter Storm Warnings in effect for the northern Rockies where 1-2 feet of snow possible above 6500 ft in portions of MT.

Wednesday starts out warm and breezy as deep upper low for this time of year moves east across the northern Rockies. Upper trough and associated cold front will move from west to east across CO Wednesday afternoon and evening. Showers and thunderstorms expected to develop along front and move through the mountains early afternoon, then into the foothills late afternoon and Metro area and plains evening. Air mass in place will be relatively dry, so do not expect large precip amounts from any showers and thunderstorms, which will also be fast moving, from the west at 15-25 mph. Precip amounts expected to be less than 0.10, with some higher amounts possible east of I-25 in heavier showers/thunderstorms. Storms not expected to reach severe limits due to lack of low level moisture, but some small hail and gusty winds possible. Most activity should be east of CO by midnight.

Thursday and Friday look mostly dry statewide. Temps Thursday near seasonal norms, warmer on Friday. By the weekend, some low level moisture expected to return from the Central Plains, so chances for showers and thunderstorms back in the forecast, mostly east of the Divide. Precip chances slight on Saturday, then better for Sunday into most of next week. Upper ridge builds back into the western U.S. so temps expected to be above seasonal norms Saturday through next week, but enough low level moisture will be present to aid thunderstorm development in the afternoon and evening hours. Storms will be slower moving, so higher precip potential will exist most of next week. This is good news for most areas, as recent warm temps and winds have dried out surface fuels. Fire districts have raised fire danger to HIGH, so any precip will help limit higher fire danger next week.

Tracking the North American Monsoon, daily average dew points in Tucson currently in the low 40's, so gradually increasing. Average daily dew point temps of 54 deg F are required to officially begin Monsoon season. Currently looks like early July time frame for the beginning of the NAM, so pretty typical start. Once the NAM makes it to CO, our fire danger should decrease as more abundant precip occurs along with higher RH values due to higher dew point temps.

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

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

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Warm and Windy day across the state today. Temps above seasonal norms, southwest winds of 15-35 mph and RH values below 10% most areas. Red Flag Warning in effect due to dangerous fire weather conditions for much of western and south central CO today, and these will likely be extended on Tuesday as well. Recent precip has kept fire danger below critical levels in the foothills as ground fuel moisture content still relatively high. Gusty southwest winds will persist this afternoon into tonight, especially over the mountains and foothills, with little RH recovery overnight.

Upper trough currently in the Pacific Northwest is forecast to move into the northern Rockies by Wednesday. This position is farther north than models suggested last week, so temps will not cool down as much and precip will be limited this week. Flow aloft will remain southwesterly until upper trough passes Wednesday night. This will keep trajectory of smoke from fires in AZ and NM into CO, so expect hazy skies and some smoke smell through Wednesday. As upper trough moves to our north, an associated cold front will move across CO Wednesday afternoon/evening. Showers and thunderstorms will likely develop along this front as it moves across CO. Because there is dry southwest flow ahead of this system, not very much moisture for system to work with, hence precip chances will be limited to brief showers and thunderstorms Wednesday afternoon and evening. Best chances will remain across the eastern plains Wednesday evening and night as better low level moisture exists there. For storms that do form, chance some could become severe as good shear profile will exist. Winds will remain fairly strong Wednesday, southwest ahead of front, and west to northwest behind front.

Thursday will be cooler with temps near seasonal norms, and dry statewide. Friday will be warmer but also mostly dry statewide. By this weekend, some low level moisture is expected to return with southeast surface winds across eastern CO. This will lead to isolated afternoon and evening showers and thunderstorms both days, with Sunday having slightly better precip chances mostly from the Divide east. Next week looks similar, with warm temps and isolated afternoon and evening showers and thunderstorms, pretty typical summer weather pattern for CO. This pattern will likely lead to ground fuels drying out some over the next 7-14 days, so fire danger is likely to increase until the North American Monsoon begins.

Longer range models continue to suggest that upper ridge will build over the western U.S. as well as over the Central U.S. by the end of June. This would then support the beginning of the North American Monsoon. We will have to wait and see how the details shake out on the timing for this.

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

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

Bump for 6/17 update

Bump for 6/18 update