265 FXUS65 KPUB 091721 AFDPUB Area Forecast Discussion National Weather Service Pueblo CO 1121 AM MDT Tue Oct 9 2018 .UPDATE... Issued at 1005 AM MDT Tue Oct 9 2018 Updated forecast to increase pops for the I-25 corridor this morning and to take down Freeze Warning for the San Luis Valley. Still looks like deformation band precipitation will be lifting northward across the area today as the upper trof ejects to the northeast across CO. Next system will be dropping into northern UT tonight with another round of snow expected for the central mountains late tonight through Wednesday. -KT && .SHORT TERM...(Today and tonight) Issued at 503 AM MDT Tue Oct 9 2018 ...Cold with Showers... Negative tilt upper trough over New Mexico early this morning will eject northeast across southern Colorado today. This will bring enough upslope component to the low and mid levels for showers across most of eastern Colorado today into this evening. The mountains and high valleys will be a little west of the trough axis, reducing the shower coverage in those areas. This system doesn't have a lot of cold air to work with and ground temperatures are still quite warm due to recent latest season heat. So not expecting much, if any, snow accumulation across most of the lower elevations today. However, precipitation intensities may reach high enough levels to drag the melting level down locally at times across the plains. This could allow a few wet flakes to mix in at times. Also, elevations above 6,000 feet, such as most of El Paso and Las Animas Counties, could see some light, slushy accumulations, mainly on grassy areas. But, for the most part, mainly just rain showers across most of the plains today. For the mountains, generally 3-7 inches of snow is expected above 10,000 feet by Wednesday morning. Below 10,000 feet, lighter accumulations of 1-3 inches will be possible. Parts of the Upper Arkansas and Wet Mountain Valleys could see local wet accumulations up to around an inch as well. For the San Luis Valley, precip chances will generally be lower than for other areas but there could still be a spotty dusting of wet snow. Tonight, precipitation will linger across the plains as it pulls slowly north and eastward, out of the area. Meanwhile, additional snow showers will continue to move across the Continental Divide. Because of the moisture and showers that will linger through the night, the low temperature forecast for Wednesday morning becomes very challenging. Despite a sufficiently cold airmass, if there are too many insulating clouds, a hard freeze may not occur. Thus, will stay with a Freeze Watch across the plains for now and let the day shift make the call on the need for a Warning. .LONG TERM...(Wednesday through Monday) Issued at 503 AM MDT Tue Oct 9 2018 Wednesday and Wednesday Night... A second deep shortwave trough and its associated jet streak will propagate into the region Wednesday morning, delivering another 5 to 8 inches of fresh snowfall over the Sawatch Mountains, 3 to 5 inches for the San Juan Mountains, and 1 to 3 inches for the Sangre de Cristo Mountains. Snow levels are around 6,500 ft over the northern reaches of the region and around 9,000 ft over the southern reaches of the region. The Palmer Divide could see some light snow showers in the morning hours on Wednesday, but it will mainly see rain as day time heating occurs. Gusty winds are expected over the San Luis Valley during the afternoon hours. High temperatures will be seasonably low with temperatures across the plains ranging from the low 40s to the low 60s, cooler north and warmer south. Some southwesterly winds are expected over the southern plains, which will help warm the air by mixing. High temperatures in the mountain valleys will be in the upper 40s to mid 50s and the mountains will range from the 20s to 30s. Lingering snow showers will persist over the Continental Divide through the overnight hours, but overall, precipitation is expected to come to a halt by the evening hours after the shortwave passes by. That shortwave will be replaced by building heights and southwesterly flow aloft. Low temperatures overnight will span the upper 20s to mid 30s for the plains and 20s for the mountain valleys. Thursday into Friday... Over the eastern plains Thursday, there appears to be some stratiform rain developing due to WAA and general upglide, as a weak lee cyclone develops off of the Rockies. The lee cyclone will also cause some mixing near the New Mexico and Colorado border, causing the high temperatures to warm around 70F in the greater Trinidad area. The warmth in that region should be isolated, since the lee cyclone will bring upslope easterly winds over the rest of the region, which should keep the temperatures cooler. The stratiform rain should dissipate overnight as the lee cyclone propagates east. Friday will be dry and will warm up slightly as the upper level flow shifts from northwesterly to westerly, enabling some downslope flow off the Rockies. Saturday through Monday... The remnants of Hurricane Sergio will make its way across the southwestern U.S. beginning Friday afternoon. As of right now, Sergio is expected to track south of Colorado, bringing some rainfall over Baca County Saturday afternoon, but model trends continue to move the low pressure center of Sergio further south. If the GFS model output verifies, the ageostrophic accelerations from wind being forced along Rocky Mountains will create gusty northerly winds as Sergio propagates by. During the overnight hours of Saturday into Sunday, a cold front is also expected to move over Southern Colorado, bringing a colder air mass and gusty northerly winds as well. The result of the two weather systems will be prolonged gusty and chilly northerly winds across the plains. Of course, the outcome of this portion of the extended forecast is subject to change, especially as Sergio nears land. It is also important to note, that the current guidance indicates that snow levels would be low enough to give the eastern plains its first snowfall of the year Saturday night into Sunday morning. As of right now, that statement is just a "heads-up", since the probability is low. && .AVIATION...(For the 18Z TAFS through 18Z Wednesday afternoon) Issued at 1112 AM MDT Tue Oct 9 2018 Rain will spread northward into the KCOS terminal around 18z which should cause MVFR cigs to drop back into the IFR category. Could be a brief mix to snow at times, but no accumulation is expected. KPUB will continue to see IFR conditions and with brief bouts of MVFR at times when rain lets up. Rain should pull off to the northeast of both terminals around 22 to 23z with slight improvement in cigs. Winds will shift around to the southeast which will cause cigs to lower again overnight with the potential for IFR to LIFR conditions at KCOS again towards morning. KALS will remain VFR, with a chance of rain showers spreading into the area during the afternoon. Brief drops in cigs to MVFR will be possible if a heavier shower affects the region, but cigs are more likely to remain VFR. -KT && .PUB WATCHES/WARNINGS/ADVISORIES... Freeze Watch from late tonight through Wednesday morning for COZ083>089-093>099. && $$ UPDATE...KT SHORT TERM...LW LONG TERM...SKELLY AVIATION...KT