wxgeek's weather-Weather Outlook June 11-20-Update 6/13

Update Fri Jun 13

Happy Friday the 13th to all. Warm and windy across the state today. Winds southwesterly in the mountains and foothills, southerly on the plains. Speeds in the 15-35 mph range with some gusts to 50 mph so far. Expect wind speeds to increase this afternoon and evening, so possibility of localized power outages and downed trees. Red Flag Warning in effect for the Western Slope as RH values generally below 15%, RH values are higher east of the Divide where surface fuels still have higher moisture content to limit fire danger, although weather conditions still quite dangerous. Winds should gradually die down overnight, although gusty winds still possible at times into Saturday morning. Temps should be 10-15 degrees above seasonal norms today. Precip chance very remote and confined to the far eastern plains this afternoon.

On Saturday, generally a pretty nice day to get out and enjoy the local activities. Winds may be gusty in the morning, but should diminish through the day. Temps still on the warm side of normal, but not as warm as Friday. A cold front associated with an upper level trough passing to our north will move through the state from west to east during the afternoon and evening. Showers and thunderstorms likely to develop along this front over the mountains and northeast CO. Precip will mostly be north of I-70, but a few showers could make their way into the foothills and Palmer Divide. Slight chance storms could become severe across the northeast plains Saturday afternoon into evening.

Sunday looks to be a very nice day to honor all the fathers. Cooler temps in wake of cold front, so temps close to seasonal norms under mostly sunny skies. Precip chances very remote statewide for Sunday with light winds.

GFS and ECMWF in better agreement today, and as usual the GFS has followed the ECMWF lead. Hence, Monday and Tuesday look dry and warm, with gusty westerly winds at times. Wednesday through Friday will feature cooler temps and better precip chances as upper trough moves into the Great basin and eventually moves across CO late next week.

Beyond next week, models suggest upper ridge will try to establish itself bringing mostly dry and warm conditions to CO through the end of 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 Thu Jun 12

Cold frontal passage has left a relatively moist and unstable air mass in place for eastern CO today. Low clouds have mostly dissipated, so heating from sun will destabilize atmosphere further. Showers and thunderstorms will develop over higher terrain today, then drift east into a more favorable environment, so expect thunderstorms in the foothills and Urban Corridor this afternoon then into the plains later this afternoon and evening. Some isolated severe thunderstorms possible, mostly east of I-25 with hail up to 1.5 inches and strong outflow winds. Storm motion today from the west at 10-20 mph. Storms should die down fairly quickly after sunset today as drier and more stable air will move in from the west.

As short wave upper ridge moves over Friday, expect very warm temps and windy conditions to prevail. West to southwest winds expected to pick up in the afternoon at 15-35 mph with higher gusts possible. Temps will be 10-15 deg above seasonal norms, and RH values under 15%, so dangerous fire weather conditions. Fortunately ground fuel moisture levels still pretty high in the foothills, but if anything does start, it could move rapidly. Gusty westerly winds likely to persist into Friday night. Precip chances very low Friday, with best chances on the far eastern plains near the KS border.

Saturday will start out breezy and warm before a cold front associated with an upper level trough to our north is expected to move down from WY by Saturday evening. Some showers and thunderstorms may develop along cold front, but mostly along the WY border, although some could push south to near I-70. Cooler temps and mostly dry conditions expected Sunday in wake of cold front, so a nice Fathers Day on tap for most of CO.

For next week, GFS and ECMWF models in vast disagreement. GFS builds a modest ridge across the western U.S. while the ECMWF develops a deep upper trough over the western U.S. GFS solution would keep CO mostly dry and with temps at or above seasonal norms, while the ECMWF solution would keep temps at or below seasonal norms and bring better precip chances into CO. Given the trend our weather pattern has kept lately, and the fact I trust the ECMWF model more than the GFS, my preference is to go with the cooler and wetter forecast for next week at this time.

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

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

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Showers and thunderstorms in progress from the foothills to the plains already today as combination of weak upper level disturbance and cold front provide the necessary ingredients for storms today. Some storms may approach severe limits east of I-25 today, so primary threat is hail and strong outflow winds. Storms should die down after sunset this evening, but could persist through midnight on the far eastern plains.

On Thursday, we will again see showers and thunderstorms develop from the mountains to the plains, but coverage and intensity expected to be less than today as upper ridge moves across CO limiting instability. Northeast flow from cold from Wednesday afternoon may push some low clouds and fog into eastern CO and up against the foothills into Thursday morning, so there will be low level to work with for storms on Thursday.

By Friday, expecting dry, warm and windy conditions over most of CO, especially from the Divide east. Temps expected to be 10-15 degrees above seasonal norms. Fire danger will be elevated in places that have not received much recent precip as RH values also expected to be below 15%, so red flag warnings a possibility in some areas of the state on Friday. West to southwest winds of 15-35 mph possible with gusts to 50 mph possible. Winds could remain gusty overnight Friday night into Saturday morning. Saturday will be breezy to start and should remain mostly dry, but an upper level trough will pass to our north and drag a cold front into eastern CO Saturday night. Some showers and thunderstorms may develop along front, but mostly north of I-70 and east of the Divide.

Sunday looks to be dry with temps near seasonal norms. Models differing some on pattern for next week, but general consensus is mostly dry conditions with isolated afternoon and evening showers and thunderstorms, mostly over the mountains and foothills. Models have continued to build upper ridge into the Southwest, but later models then continue the pattern of weak upper level disturbances moving from the Pacific across the northern Rockies. As these system pass, precip chances increase, then decrease as short wave upper ridge builds back in. A fairly progressive pattern for mid to late June for the U.S. If this pattern persists, North American Monsoon will have a hard to getting going, as it depends a great deal on a strong upper ridge forming across the south central U.S.

Models also suggesting a possible tropical storm forming in the Gulf of Mexico late next week, but too early to put much stock in that.

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

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

Bump for 6/12 update

Bump for 6/13 update