889 FXUS65 KPUB 230103 AFDPUB Area Forecast Discussion National Weather Service Pueblo CO 703 PM MDT Thu Oct 22 2020 .UPDATE... Issued at 701 PM MDT Thu Oct 22 2020 Updated to end the Red Flag Warning that was in effect today. && .SHORT TERM...(This evening through Friday) Issued at 701 PM MDT Thu Oct 22 2020 Main Forecast Concerns/Challenges: 1) Gusty northerly winds and blowing dust this evening 2) Patchy fog, possibly dense, near the Palmer Divide tonight and Friday morning 3) Potential for light snow and/or freezing drizzle mainly around the Palmer Divide late tonight into Friday morning In the near term, cold front continues to steadily move across the eastern plains with stronger northerly winds ushering in colder conditions along with higher RH values. While winds remain gusty, gusting up to around 40 kt, higher dewpoint air and RH values are helping to improve the critical fire weather conditions which were in place across the area for much of the day. Was able to expire and cancel part of the Red Flag Warning earlier today, but locations west of the I-25 corridor are still meeting criteria and have left these areas in the Warning. The current end time by early this evening still looks to be on track though. The low stratus and fog discussed earlier today has remained in place, not advancing much beyond the Palmer Divide and Kiowa county. However, do think as we go into this evening, should see this begin to steadily spill south with cloudy skies under lower stratus likely for much of the plains by this evening into Friday morning. The fog from this morning has also improved, though do have some concerns it will redevelop later tonight as ceilings lower. Guidance not really showing this trend though given the moist conditions already in place and additional low level ascent and moistening expected tonight, think its still a possibility and have maintained mention in the grids for areas around the Palmer Divide. Low stratus and fog Friday morning should slowly improve through the day, though veering low level flow to a southerly direction will likely reinforce this cloud cover. As additional moisture arrives later tonight, moist upslope flow is appearing to support some light precip development. Most guidance hinting at this possibility, especially for areas around the Palmer Divide. The moisture will likely be shallow and lack crystals, however, additional CAA tonight will cool the column. Forecast soundings showing some moisture in the 8-10c range later tonight and while that is on the very low end for crystal potential, crystals and the potential for snow will remain possible given the persistent ascent. Don't think it will be enough for all snow, and have concerns for periods of either light snow or freezing drizzle. With much colder temps tonight, surface temps will likely fall below freezing and support some slick conditions for the Friday morning commute. Have included this in the forecast and will increase messaging for the potential hazardous conditions for the Friday morning commute. .LONG TERM...(Friday night through Thursday) Issued at 701 PM MDT Thu Oct 22 2020 ...Increasing Fire Danger on Saturday... ...Much Colder with Snow Sunday and Monday... Friday night-Saturday...Moderate to strong west to southwest flow aloft continues across the region through the day Saturday as the next strong system digs across the Intermountain West. This will keep a cool shallow airmass across the southeast plains through the evening, with lee troughing expected to develop and deepen across the plains through the early morning hours on Saturday. This will allow for the stronger winds aloft to mix down and erode the cool airmass in place through out the day. The breezy conditions will bring increased fire danger across the area Saturday, with the greatest concern for critical fire weather conditions expected across the mid Arkansas River Valley, the San Luis Valley, the lee slopes of the southeast Mts and the southern I-25 Corridor, where a Fire Weather Watch has been issued for Saturday afternoon and early evening. Temperatures Saturday to warm back to above seasonal levels in the mid 60s to upper 70s across the plains, with mainly 50s and 60s across the higher terrain. Saturday night-Monday night...Latest models continue to indicate a drastic change in the weather through this period, as the Intermountain West system digs across the Rockies through early next week. The latest GFS runs have trended towards a slower and further south and west solution of the EC, however, the latest EC runs are indicating a further south and west splitting trough solution, as part of the system moves across the area Sunday through early Monday, with secondary energy digging across the Great Basin and closes off an upper low across the Desert SW Monday night. Despite these differences in solutions, all solutions point to a strong arctic front moving across eastern Colorado late Saturday night, with a much colder airmass moving across the plains through the day Sunday. This cold airmass will continues to push south and west across all of Colorado Sunday night and Monday. This cold airmass, combined with moisture and lift associated with the upper trough, will bring a period of snow to all of south central and southeast Colorado Sunday afternoon through Monday, with the best snow accumulations expected across the higher terrain, especially the eastern San Juan and Sangre de Cristo Mts, where 1 to locally 2 feet of snow may be possible through early Tuesday morning. Snow amounts still will depend on how the system tracks across the region, though could see 6 to 12 inches across the rest of the higher terrain, with 3 to 6 inches possible across the high mountain valleys and portions of the I-25 Corridor, with up to a few inches possible across the plains. Temperatures are expected to well below seasonal levels, with highs Sunday in the 20s and 30s across the plains likely reached early in the morning and highs on Monday likely only in the 20s and 30s, warmest across the high mountain valleys. Lows could be in the single digits and teens, with any precipitation expected to bring icy conditions on area roadways for the Monday morning commute. Tuesday-Thursday...Drier weather and a slow warming trend remain in the offing through the rest of the week. && .AVIATION...(For the 00Z TAFS through 00Z Friday evening) Issued at 701 PM MDT Thu Oct 22 2020 Conditions across ALS will remain VFR and dry, with gusty west southwest winds expected into this evening and again on Saturday. Active weather expected across COS and PUB this period, with gusty north northeast winds into this evening. These higher winds will also support some blowing dust, though vis is not expected to be too restricted at this time. IFR and MVFR ceilings to the north will expand and fill southward into this evening, with overcast skies then likely for much of the period. Some improving trend likely by Saturday afternoon though. At this time, the lowest ceilings should stay just to the north of COS with low end MVFR ceilings currently forecast. However, will continue to monitor as could easily see a period of IFR ceilings late tonight into Friday morning. For PUB, have higher confidence for ceilings remaining MVFR. Some patchy freezing drizzle or light snow is possible around the Palmer Divide later tonight into Friday, though this development looks to stay just to the north of COS. Similar to the ceiling forecast, will closely monitor as it could possibly spill more south towards COS. && .PUB WATCHES/WARNINGS/ADVISORIES... Fire Weather Watch from Saturday afternoon through Saturday evening for COZ222-224-225-229-230. && $$ UPDATE...28 SHORT TERM...RODRIGUEZ LONG TERM...MW AVIATION...RODRIGUEZ