wxgeek's weather-Weather Outlook May 27-June 6-Update 5/29

Update Thu May 29

Moisture plume streaming north from remnants of tropical storm Amnada currently across AZ, NM UT and western CO. This is helping to fuel storms from the mountains into the foothills of CO. Storm motion from the southwest, but very slow today, 5-10 mph so any storms that form could drop heavy rain in localized areas. Storms may drift onto the Urban Corridor this afternoon and evening, but atmosphere is drier and more stable farther east today. Generally less then 0.25 inches of precip expected today, outside localized heavier amounts.

Friday looks to be a wet day across CO. Precip expected to start early across western CO, and move east by late morning and early afternoon into the foothills and plains. Storm motion again from the southwest, and slightly faster at 5-15 mph, but this slow speed has the potential to cause localized flooding. Precip amounts up to 2 inches possible in areas Friday, so flooding will be possible, especially in areas already near flood levels. Flash flooding also possible in foothill areas, as focus of heavy rain will be along the Urban Corridor and foothills most of the day. A weak cold front will push into northeast CO Friday afternoon, so storms will focus on this boundary and not move much. Storms then expected to move onto the plains Friday evening into Friday night.

Atmosphere dries out some on Saturday, but enough residual moisture and instability will exist to fire storms across the mountains and foothills in the afternoon and drift into the Urban Corridor and adjacent plains later afternoon into evening. SPC has issued a slight risk of severe thunderstorms for northeast CO Saturday afternoon/evening.

Further drying occurs Sunday, with only a slight chance of precip statewide Sunday, mostly over higher terrain, as temps cool back to near seasonal norms. Monday though Wednesday also look mostly dry statewide with temps near seasonal norms. Precip chances increase late next week as saggy upper trough moves over CO, so cooler temps and better precip chances into 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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Update Wed May 28

Sunny and warm start to the day today as upper ridge builds over CO. Isolated showers and thunderstorms possible today, mostly from the mountains to the foothills as atmosphere is relatively dry and only slightly unstable. Any storms that do form not likely to produce that much rain, so no real flood concerns with precip today. Biggest concern today would be dry lightning strikes and gusty outflow winds with storms. Storm motion today will be from northwest to southeast. Temps expected to be 10-15 degrees above seasonal norms today with low 90's across the Urban Corridor.

For the remainder of the week, temps will cool slightly as clouds increase and precip chances increase. Some additional moisture from Tropical Storm Amanda which is south of Cabo San Lucas will help fuel storms Thursday and Friday. Precip chances Thursday will extend from the mountains to the Urban Corridor, and will extend farther to include the plains on Friday. Storm motion Thursday and Friday will be from the southwest to northeast at 5-15 mph, so the potential for flash flooding and small hail back in the picture, especially Friday when heaviest precip chances exist. Areas in heavier storms could see a quick inch or two of precip, with most areas seeing 0.25 to 0.75 inches for the 2 day period. Additional rain will aid in flood concerns for areas already at or near flood stage.

Saturday will see additional precip chances, but coverage and amount should be less than Friday. Upper trough from the west coast will flatten upper ridge over CO on Sunday, so cooler temps but only very isolated precip chances Sunday. Monday and Tuesday next week look to be mostly dry statewide, with temps back near seasonal norms. Models then suggest baggy upper trough to settle across the central Rockies mid to late next week, which will keep temps on the cool side of normal and increase precip chances Wednesday into next weekend. With snow melt continuing, any additional precip will further increase stream and river levels and increase flood concerns along prone areas. Fire danger looks to remain in the low to moderate range through next weekend. Models suggest building another upper ridge the following week, which would increase temps and possibly elevate fire danger as only isolated afternoon precip would exist.

As stated yesterday, CPC has issued latest seasonal forecast of above normal precip for CO for June through August. Given the building El Nino in the Pacific, this forecast makes sense as the North American Monsoon is usually strong with a building El Nino. Additionally, the building El Nino will likely cause an increase in tropical cyclone activity in the eastern Pacific this summer, which adds additional moisture to the North American Monsoon. Hence, odds look good for a wetter than normal summer, which would likely keep temps at or below normal.

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

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

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Warmer and drier weather across the state today as upper ridge begins building in as our wayward upper low continues moving east. Flow aloft northerly today, northwesterly Wednesday before turning to southwesterly later this week. Temps will remain above seasonal norms today through Saturday as upper ridge remains in place. Not until Sunday the upper ridge flattens as short wave upper trough moves across from the Pacific.

For precip chances, today will see only very isolated showers and thunderstorms over the High Country, mostly sunny elsewhere. Precip chances then gradually increase each day this week. Coverage on Wednesday expends from the mountains to the foothills, then expands into the Urban Corridor on Thursday into Saturday. Best precip chances for the foothills will be Thursday into Saturday, with Friday being the wettest day. Models suggest up to 1.0 inches of rain may fall in mountains areas from today through Saturday, with 0.25 to 0.75 inches possible in foothills and Urban Corridor areas. For most areas, just enough moisture to keep fire danger down, but for mountain areas, precip combined with warm temps will produce significant runoff this week, so streams and rivers fed by snowpack runoff will be running quite high this week, and may approach flood levels. Many rivers and streams east of the Divide are already at or near flood stage, and levels expected to rise this week. Snow level looks to remain above 14,000 ft this week, so all precip looks to be rain.

As upper trough flatten upper ridge, Sunday through next Wednesday look to be cooler and drier, with limited precip chances statewide, and temps near seasonal norms. Better precip chances look to return next Thursday into next weekend.

The Climate Prediction Center forecast calls for near normal temps and above normal precipitation from June through August. Good news for fire danger, but instead of June being a bad fire month, we could see more flooding due to snowmelt and rainfall. Always a fine balance.

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

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

Bump for 5/28 update

Bump for 5/29 update