718 FXUS65 KPUB 300026 AFDPUB Area Forecast Discussion National Weather Service Pueblo CO 526 PM MST Fri Nov 29 2019 .UPDATE... Issued at 513 PM MST Fri Nov 29 2019 Updated for expiration of High Wind Warning in the southern two- thirds of the San Luis Valley, Huerfano, Las Animas, and Baca Counties. && .SHORT TERM...(This evening through Saturday) Issued at 243 PM MST Fri Nov 29 2019 ...Potent storm bringing heavy wind driven snow to the mountains...and damaging winds to portions of the southeast plains through Saturday... Upper low over the western U.S. was ejecting an impulse of energy with an associated 150 kt upper jet across southern CO this afternoon which has resulted in heavy wind driven orographically enhanced snow across the southwest mountains. A line of rain/snow showers along the leading edge of this impulse has progressed eastward into the adjacent plains as of 22z. Brief poor visibility and blowing snow accompanied this squall as it passed through the San Luis Valley earlier this afternoon but warmer temperatures across the plains should keep precipitation as rain. Some brief embedded ice pellets or small hail will be possible with some of the more intense embedded echoes across the plains as the line rolls eastward but overall intensity should decrease as it moves away from the mountains. Meanwhile, high winds have impacted the San Luis Valley, Huerfano and Las Animas counties this afternoon with gusts up to 75 mph reported at the TAD ASOS. Expect these strong winds to continue for another hour or two across the southern portions of the area before decreasing again briefly this evening. As the upper low lifts to the northeast and intensifies across northeast CO/western NE, we start to loose a lot of forward wind shear aloft and a mtn top inversion sets up. Cross-sections continue to look favorable for a mountain wave high wind scenario tonight into Saturday with high winds initially across the higher peaks this evening, spreading into the adjacent lower elevations after 10 pm. High res HRRR runs have advertised this well with each successive run and have leaned heavily on it for headline issuances this afternoon with most areas under high wind warnings starting tonight and continuing through Saturday. Gusts up to 85 (perhaps 90 mph) will be possible across the higher peaks and east facing slopes of the mountains, with gusts up to 65 to 75 mph along the adjacent I- 25 corridor, and gusts to 60 mph farther east. As the storm wraps up to the northeast, strong winds will spread into portions of Kiowa county and have added a high wind warning for this area for Saturday afternoon into the evening hours. Mountain wave parameters break down by mid afternoon with highest winds continuing across the higher peaks and far northeast portions of the southeast CO plains into early evening. As far as winter highlights go, current suite of headlines still looks on track with winter storm warnings going across the southwest mountains through Saturday morning, and advisories persisting across the central mountains through the morning. Although snow decreases in the afternoon, high winds will continue across the Sawatch range so will keep the high wind warning going through 6 PM up that way as blowing snow will be the major concern anyway. The southwest mountains will continue to see some orographically enhanced snow showers with westerly flow favoring southern sections of the range into the morning for a few more inches of snow through the morning hours. Overall, an active weather pattern over the next 24 hours. Travel will be difficult due to snow in the mountains and strong cross winds across the lower elevations. Power outages, and damage to trees and structures will all be possible with the greatest threat in and near the mountains, though depending on how quickly the storm wraps up across northeast CO and NE, a high wind threat may extend across portions of the far eastern plains tomorrow afternoon through into the evening. -KT .LONG TERM...(Saturday night through Friday) Issued at 243 PM MST Fri Nov 29 2019 Fairly decent agreement with the operational solutions with slight differences with a disturbance mid week. Ensemble spreads do increase with time, but not bad, so confidence through the extended period is a big higher. Saturday night...the large upper level low over the Central Plains will continue to eastward march with conditions quieting down by morning. Winds will be gusty during the evening out near the Kansas border, but should dissipate after midnight. A few light snow showers are possible during the evening over the Central Mountains, ending towards midnight. Dry conditions will then prevail across the region into Sunday morning. Sunday through Tuesday...high pressure is forecast to move across the Rockies from Sunday into Tuesday. Generally dry conditions are expected with the high pressure as it moves overhead. The GFS does try and develop light snow showers over the Central Mountains Monday night, but both the NAM and ECMWF are dry, and followed those two models with dry conditions. Temperatures will warm through the period, from the upper 40s on Sunday, into the mid to upper 50s by Tuesday. Wednesday into Thursday...a quick moving shortwave trough over the western states is forecast to shift eastward across the region beginning Wednesday, and exiting on Thursday. Snow will move into the Continental Divide by Wednesday afternoon and prevail through Thursday afternoon. A cold front will drop south across the Plains Wednesday night with a northerly wind shift. As far as precipitation for the lower elevations, much will depend on storm track. The GFS is south across the Desert Southwest and keeps precipitation confined to the mountains. The ECMWF is further north, with precipitation spreading out across the Plains on Thursday as the upper system moves east. Friday...as the upper system departs to the east, high pressure over the Great Basin will shift east into Colorado. Dry conditions are expected for Friday. Mozley && .AVIATION...(For the 00Z TAFS through 00Z Saturday evening) Issued at 243 PM MST Fri Nov 29 2019 Band of showers will continue to move eastward affecting the TAF sites through 23-00z. Winds will be locally gusty up to 45 kts with the showers. VFR conditions return with winds decreasing this evening at all 3 terminals before increasing again towards midnight. This will put a period of LLWS this evening through 14z for both KCOS and KPUB with winds off the surface from the northwest at 60 kts. Winds will increase at both terminals around 15-16z with gusts up to 55 to 60 kts from late morning into the afternoon. KALS will see gusty winds through the night with winds becoming northwesterly with gusts up to 45 kts on Saturday. Mountain snow showers and obscurations will continue into tonight, though improvement is expected across the Sangre De Cristo mountains this evening as drier air spreads in. -KT && .PUB WATCHES/WARNINGS/ADVISORIES... High Wind Warning from 10 PM this evening to 3 PM MST Saturday for COZ077-078-083>088-094. High Wind Warning from 10 PM this evening to 6 PM MST Saturday for COZ060-061-072-074-076-079-081. High Wind Warning from 11 AM to 7 PM MST Saturday for COZ096. Winter Weather Advisory until 11 AM MST Saturday for COZ058-060- 061. High Wind Warning until 6 PM MST Saturday for COZ073-075-080-082. Winter Storm Warning until 8 PM MST this evening for COZ073-075. Winter Weather Advisory until 8 PM MST this evening for COZ072- 074. Winter Storm Warning until 11 AM MST Saturday for COZ066>068. && $$ UPDATE...28 SHORT TERM...KT LONG TERM...MOZLEY AVIATION...KT