wxgeek's weather-Last week of summer forecast-Update 9/18

Update Thu Sept 18

Very nice weather across the state today under mostly sunny skies and temps 5-15 degrees above seasonal norms. Indian Summer type weather should persist Friday, with only some isolated afternoon and evening showers expected over the High Country. Above average temps should persist on Friday as well.

Things begin to change over the weekend, as temps will cool back to near seasonal norms, and additional moisture will bring better precip chances statewide. On Saturday, best precip chances will remain over the High Country with chances moving east into the foothills and adjacent plains with isolated thunderstorms possible. Better chances statewide on Sunday with scattered afternoon and evening showers and thunderstorms possible.

For next week, Monday will begin with isolated afternoon and evening showers and thunderstorms, then Tuesday through Friday an upper ridge will build over the Great Basin and keep CO mostly dry with temps at or above seasonal norms for the first week of Fall.

By late next week into next weekend, medium range models are suggesting a big change to the pattern. Deep upper level trough is forecast to move from the west coast into the Great Basin by next Friday, then move across CO next weekend. Models suggest robust precip amounts will be possible from next Friday through Monday, especially western CO. At this time, models keep snow level mostly above 10,000 ft so believe this will mostly be a rain event except for higher elevations. Will keep an eye on how this evolves, as it has some flood potential and if colder air is introduced, it could become a snow event to lower elevations.

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

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

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As the last week of summer is upon us, fairly nice weather will see us through the end of summer. Remnants of Odile, now a tropical storm, will move into AZ and NM the next 24-48 hours. Some very heavy rain is expected and flash flooding looks likely across portions of AZ and NM. Southern Co may see some precip on Thursday, but would remain south of US 50. Otherwise, near normal temps and mostly dry conditions are expected across CO through Thursday. By Friday, some moisture may make it into CO as a cold front drags across CO late in the day. Best precip chances will be over the mountains.

For the weekend, slightly better precip chances will move into CO associated with moisture from yet another tropical storm (TS Polo) moving up the Baja peninsula, and a weak upper trough moving slowly from CA across CO through early next week. Heaviest precip looks to be along and west of the Divide Saturday and Sunday, then will move into eastern CO Monday and Tuesday. By late next week upper ridge builds back over the western U.S. and will keep temps warm and mostly dry conditions for CO.

Long range models indicate upper ridge will remain in place through the end of September, so mild temps and mostly dry conditions are expected for CO through late September.

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

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

Bump for 9/18 update