074 FXUS65 KGJT 102231 AFDGJT Area Forecast Discussion National Weather Service Grand Junction CO 431 PM MDT Wed Oct 10 2018 .SHORT TERM...(Tonight through Thursday night) Issued at 430 PM MDT Wed Oct 10 2018 Well that could have gone better. The amount of water being transported into this storm that hung on our northern border was well underestimated so the snow seen on webcams north of Hermosa and the Purg stake was a big surprise to #15. The 300-305K surfaces again show a strong transport of moisture northward from the Gulf of California into central Colorado overnight. This will be induced by pressure falls to our West as heights fall with the next digging trough. Models have not backed off on the idea a strong band of precipitation forming in the downstream of this trough where frontogenesis is favored in the indirect circulation of the subtrop jet max moving overhead. The area of precipitation should blossom over SE Utah late this evening ahead of the jet then congeal into an elongated area of precipitation from the Uncompaghre to the Central Mountains. The Grand Mesa has done well the past several days and it appears this island in the sky will do the same with this storm. As usual snow levels and temperatures will be key to snow amounts and have gone with another advisory above 9000 feet. The one caveat will be forcing under this fronto band lowering snow levels well below this level. A similar situation recently resulted in 19 inches of snow in Craig as opposed to the 2 inches in my forecast. Confidence is never high enough this far out to forecast this but will be watching things closely tomorrow. For now snow and the morning commute in the central mountains should be enough to support the advisories as similar conditions were found today. This storm has a second punch as well with cold air and orographics coming into the mix tomorrow evening as the main trough swings through. Dendritics will be briefly favorable for some better snow rates before drying takes over and snow tapers off by early Friday. .LONG TERM...(Friday through Wednesday) Issued at 430 PM MDT Wed Oct 10 2018 Friday into Saturday will a drier forecast with a gradual warmup ahead of the next very cold trough diving in from the Canadian Prairies. This arrival of this trough will keep Sergio pinned well to the south. The models have begun to diverge a bit on the strength and timing of this trough as it digs in on Sunday across the Central Rockies. The Euro is no much sharper and farther West with the main energy which means a much colder forecast. The GFS has maybe taken a lean the other way. Expect some precipitation with this trough and most of will likely be in the form of snow due to the temperatures involved. A cool down with freezing temperatures becoming more probable in some of the lower valleys could mean additional threats besides snow. The strong ridge in the Pacific will be slowly migrating eastward through the first part of next week which should bring a gradual warming trend by late next week and possibly another push of moisture as a system in the Southwest lift through. && .AVIATION...(For the 18Z TAFS through 18Z Thursday afternoon) Issued at 1144 AM MDT Wed Oct 10 2018 Scattered valley rain and mountain snow showers will continue through 03Z this evening before ending for the night. Expect occasional MVFR/IFR conditions as showers pass through with snow levels around 7k. Conditions improve from west to east this evening, but deteriorate once again after midnight with another round of showers passing through the region. Mountains will be frequently obscured for another 24 hours. && .GJT WATCHES/WARNINGS/ADVISORIES... CO...Winter Weather Advisory from midnight tonight to midnight MDT Thursday night for COZ009-010-012-013. UT...None. && $$ SHORT TERM...15 LONG TERM...15 AVIATION...JDC