718 FXUS65 KPUB 161729 AFDPUB Area Forecast Discussion National Weather Service Pueblo CO 1129 AM MDT Sun Oct 16 2022 .SHORT TERM...(Today and tonight) Issued at 343 AM MDT Sun Oct 16 2022 Key Messages: 1) Cool with lots of mid and hi level clouds today. 2) Frost/Freeze for parts of plains tonight. 3) Some light snow higher elevations south of US50. Currently... Quite a bit of high cloudiness was noted streaming in from the south over the region early this AM. Mid level cloudiness was noted banked up just east of the mtns extending to roughly the I-25 corridor region. Temps at this hour were relatively mild, with 40s to around 50 over the plains and valleys (with a mid 50 reading at KPUB), with 20s and 30s mtns. Reverse gap flow winds were still noted over the San Luis Valley (SLV) as KALS was still gusting rather strongly from the east. Today...Main concern today will be the noticeably cooler temps over the fcst area. Most of the plains will be in the 60s with 50s on the divides. With lots of high and mid level clouds over the region, it will feel cooler than the ambient temperature readings. However, winds will be rather light region-wide through the day. As for precip, some very light showers of rain and hi elevation snow will be possible today, with most of the activity occurring mainly along the CO/NM border. Any snow accums will be rather light. Overall best chances will be southern Sangres south of La Veta to the NM border. Tonight... Main concern shifts to cold temperatures. After coordinating with surrounding WFO's, have gone with a freeze warning for the plains counties mainly along and north of US-50. Most areas should see temps in upper 20s to lower 30s. I do not see a hard freeze at this time. As for Pueblo county, main concern will be frosty conditions, mainly over the eastern part of the county (~Pueblo West eastward). Farther south, clouds may linger towards morning and this will likely keep temps a bit warmer, limiting the freeze threat. Any precip over the southern tier should end by early to mid evening. \/Hodanish .LONG TERM...(Monday through Saturday) Issued at 343 AM MDT Sun Oct 16 2022 Key messages: 1) Areas of frost and freeze conditions will impact much of the plains and the Wet Mountain Valley during the early morning hours on Monday, Tuesday, and Wednesday. 2) Showers and a few high elevation snow showers will be possible over the southern mountains, Raton Mesa, and southern half of the San Luis Valley on Monday until around midnight. 3) A gradual warmup will occur early next week as the ridge begins to build back over the western states and influences the region with warmer and drier conditions. 4) A trough could influence the region by next weekend with some high elevation snow, lower elevation rain, increased winds, along with cooler temperatures. Detailed discussion: Monday... The U/L low over the center of the state of New Mexico will continue to fill and move off over the panhandle of Texas, becoming absorbed into the trough downstream as it does. This could still provide enough mid level instability over the southern Sangre de Cristo and San Juan Mountains for a few showers and even a stray thunderstorm or two during the afternoon hours on Monday. Some light rain and/or drizzle will also be possible along the front range and eastern facing slopes, upper Arkansas River Valley, as well as the southern plains and I-25 corridor due to upsloping. Areas of frost and freeze conditions will impact much of the plains north of highway 50 and along the northern I-25 corridor during the early morning hours, for this reason, there are Freeze Warnings in place for Kiowa, Crowley, Prowers, and El Paso Counties, and a Frost Advisory for Pueblo County. The cP airmass will continue to modify with surface winds turning more southerly, with temperatures gradually warming back to being closer to the seasonal average for highs on Monday. There could still be a few showers and even some very high elevation snow over the southern mountains continuing into Monday night, and perhaps even some showers with upsloping over western Las Animas County along the southern I-25 corridor and Raton Mesa area. Nothing more than a dusting or perhaps an inch of snow on the highest peaks is expected. All showers should end by around midnight. Lows on Monday will be much cooler under clearing skies and there could also be some areas of frost over much of the plains, Wet Mountain Valley, and especially northern I-25 corridor (Palmer Divide), mainly north of highway 50, and also possibly widespread within the lower Arkansas River Valley. The highest concentrations of widespread frost will be possible for Kiowa County and northern Prowers County. Tuesday through Friday... Tuesday and Wednesday morning will still have some frost/freeze concerns for many areas of the plains, mainly north of highway 50 and east of the I-25 corridor, and within the Wet Mountain Valley. Ensembles and deterministic models alike have been relatively close in agreement with a ridge continuing to build over the western states and slowly progress eastward and over the region. This will continue to keep things on the drier side and also result in a gradual warmup in temperatures through Wednesday with highs getting back above the seasonal average and close to the 80 degree mark for areas of the lower Arkansas River Valley. Temperatures will be slightly cooler on Thursday, but still remain slightly above the seasonal average. Temperatures will further warm back into possibly the low 80s for the lower Arkansas River Valley on Friday as the ridge temporarily strengthens ahead of the deepening trough upstream. Saturday through Sunday... Models begin to show some discontinuity by this period in the forecast, although there is a general consensus of a trough upstream beginning to deepen and impacting southeast Colorado throughout the weekend. Both the ECMWF and the GFS show a cutoff U/L low south of California on Saturday that becomes absorbed in the trough, although only the GFS has this feature moving far enough to the north to add more mid and upper level moisture into the longwave trough. The Canadian does not have this U/L low and instead has a closed low forming over New Mexico by later in the day on Sunday, which provides the best wrap around moisture and gives southeast Colorado the best chance of precipitation on Sunday. The ECMWF continues to show a more negatively tilted axis than the GFS, as it has for the past several runs. This more negatively tilted axis is also reflected in the EPS (European ensemble), with the mean 500mb geopotential height being centered directly over Colorado late Saturday. The GEFS ensemble doesn't have this trough as broad and as negatively tilted, and also keeps the progression slower with the axis remaining west of Colorado until late Sunday. The tightening of the gradient is likely to result in some stronger winds over the region throughout next weekend, and also provide a southwesterly flow with orographically induced snow showers over the mountains, mainly central and southwest mountains. What this trough will do and how it propagates will need to be further evaluated in the upcoming days, although it can be said that it is looking more likely that there will be a significant trough impacting the region by sometime early next week. This could possibly bring the season's first measurable snow to many areas, including the plains, with much colder temperatures in place. -Stewey && .AVIATION...(For the 18Z TAFS through 18Z Monday afternoon) Issued at 1122 AM MDT Sun Oct 16 2022 KALS...MVFR to VFR through this afternoon due to low CIGS around 5 kft. A few rain showers will likely impact the southern San Luis Valley into this afternoon, but will likely not impact the terminal. Left VCSH out of the TAF for now, but a rain shower may be possible this afternoon. VFR conditions are expected overnight into Monday. KCOS and KPUB...MVFR to VFR conditions due to low CIGS into this afternoon, with VFR conditions expected overnight into Monday. Winds will generally be light through the period. Mozley && .PUB WATCHES/WARNINGS/ADVISORIES... Freeze Warning from midnight tonight to 9 AM MDT Monday for COZ084-085-089-095-096-098. Frost Advisory from midnight tonight to 9 AM MDT Monday for COZ086. && $$ SHORT TERM...HODANISH LONG TERM...STEWARD AVIATION...MOZLEY