591 FXUS65 KGJT 232105 AFDGJT Area Forecast Discussion National Weather Service Grand Junction CO 205 PM MST Sun Feb 23 2020 .UPDATE... Issued at 203 PM MST Sun Feb 23 2020 Current webcams showing some snow at the higher elevations but the majority of accumulating snowfall looks about over. Visible satellite imagery showing plenty of holes through the cloud cover and disorganization associated with the low. With that, went ahead and cancelled the rest of the advisories across the area. UPDATE Issued at 1057 AM MST Sun Feb 23 2020 The low continues to move across Colorado at this hour and has almost made it over to the Front Range. Snow continues under the banding that has set up over the northern valleys and northern facing side of the Book Cliffs. As the low continues to drift eastward, precip will end from west to east though some snow showers are possible through this afternoon. Even so, significant accumulations have ended for the San Juans, La Sals, and Grand Mesa so went ahead and cancelled those advisories. && .SHORT TERM...(Today through Monday) Issued at 453 AM MST Sun Feb 23 2020 A well defined clear slot has wiped out quite a bit of the precipitation in our southern CWA. Two main areas of precipitation remain...one focused in the deformation zone arcing from northwest Colorado back toward the parent low in central Utah. The other area of heavier precip is in the unstable air the nose of the dry slot which is lifting across the central mountains early this morning. This low will be getting a nudge eastward by the arrival of the next upstream system digging into the PacNW. The ascent from the low overhead and conditional instability will keep a threat of moderate to heavy snow showers at times today with the best focus over the central mountains. The northern San Juans will also be favored at times this afternoon and early evening as the flow turns northerly on the back side of the low. In the end there could be some higher amounts thanks to the convective banding but overall the warm nature of the storm and dry slot put some limitations on this system. Much of the snow will taper of this evening as the storm progresses into the Plains. The upstream kicker system will be arriving during the pre dawn hours bringing much colder air into the mix. Snow-2-Liquid ratios 12:1 or less will be closer to 20:1 up north snow begin to spread across the northern and central mountains through Monday morning. Moisture is very underwhelming in this cold storm but snow amounts should be inflated and on the fence on whether winter headlines needed attm. This snow will be easily blown around and this will come into play but mainly near to above timberline. Impacts to travel will also be a concern from Rabbit Ears down to Vail with much colder air also playing a role at elevation. The Park and Flat Tops look to benefit the most from this storm. .LONG TERM...(Monday night through Saturday) Issued at 453 AM MST Sun Feb 23 2020 Cold northerly flow on the backside of the trough will bring an anomalously cold air mass to the area. 700 mb temperatures drop to 10-20 C below zero on Tuesday with goose feather snow still falling over the higher terrain of the central and northern mountains through the day. Models suggest some clearing in the evening with thin overcast moving in early Wednesday morning. This will be a difficult forecast but much like last week the Yampa valley could end up well below normal and current guidance. We stay in the northwest flow with a week wave moving through Wednesday night into Thursday and bringing a small chance of snow to the high Park range. Beyond this an expansive ridge builds over the western CONUS allowing for temperatures to moderate and conditions to dry out. && .AVIATION...(For the 18Z TAFS through 18Z Monday afternoon) Issued at 1031 AM MST Sun Feb 23 2020 The closed low responsible for the clouds and rain/snow is moving across western Colorado and continues to bring precip to the region. However, conditions will be improving through the afternoon and evening hours. Until then, expect MVFR to IFR ceilings and vis from time to time for KHDN, KASE, and KEGE. These TAF sites will be moving from category to category as a heavier shower moves through...drops cig/vis...then jumps back up as the shower leaves. Expect this to continue through 00 to 02Z before clouds start to lift and precip stops. Remaining TAF sites will likely stay VFR though a quick drop under a stronger showers is not out of the question. && .GJT WATCHES/WARNINGS/ADVISORIES... CO...None. UT...None. && $$ UPDATE...TGR SHORT TERM...15 LONG TERM...15/TGR AVIATION...TGR |