Area Forecast Discussion
Issued by NWS Grand Junction, CO
Issued by NWS Grand Junction, CO
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748 FXUS65 KGJT 091739 AFDGJT Area Forecast Discussion National Weather Service Grand Junction CO 1139 AM MDT Thu May 9 2024 .KEY MESSAGES... - Snowfall will favor the eastern Uinta mountains in northeast Utah and the higher elevations of the San Juans and central Colorado mountains today through Friday. - Snow amounts in excess of 6 inches have a 50 to 60 percent probability of occurring over the highest peaks of the eastern Uintas...eastern San Juans and Elk mountain over the next 48 hours...with lesser probability of at least 30 percent along the travel corridors. - Unsettled conditions will persist through the weekend along with a slow warming trend...however temperatures will remain below normal. && .SHORT TERM /THROUGH FRIDAY/... Issued at 315 AM MDT Thu May 9 2024 Satellite indicates the low circulation is descending southward somewhere over west-central to southwest Utah early this morning. This low will eventually become closed and cut off from the main flow somewhere around east-central Utah late this morning into early afternoon and settle over southern Utah by late this afternoon and evening. Two particular areas are favored for snowfall in this pattern. The first is the eastern Uinta mountains under northeast flow this morning through early afternoon as the low circulation descends. The second is the eastern San Juans and spine of the Sawatch Range in the central Continental Divide, including Monarch Pass and Wolf Creek Pass which are actually in PUB`s CWA. The eastern spine of our Sawatch and San Juans picks up late this afternoon and continues through Friday afternoon for the most part as the cut off low spins over southern Utah and retrogrades a bit westward towards Las Vegas. This will advect some moisture around the low, along with daytime instability and orographics to generate snow at the higher elevations. The probability that snowfall amounts over this 48 hour period exceed 6 inches in these higher elevations along the eastern fringe of our Sawatch Mountain zone and San Juans is 50 to 60 percent...same with the higher elevations of the eastern Uintas. The majority of these zones however as you get further away from the eastern spine in the San Juans and West Elks towards our main travel corridors has a 30 to 40 percent chance of exceeding 6 inches. The main travel corridors on the western side of the divide remain limited in terms of impacts as roads should remain wet with maybe 2 to 4 inches of snow, possibly up to 5 at the highest elevations, for each 24 hour period both today and Friday. Snow accumulations appear limited to areas mainly above 10,000 feet. The flow pattern around this cut off low also is favoring the eastern upslope areas of the eastern San Juans and central mountains, which is more on the Front Range side than our western slope side. Therefore, opted not to issue any Winter Weather Advisories with this package as impacts appear limited to the higher elevations along the eastern spine of our shared San Juan and Sawatch Mountain zones. Winter just won`t let go for our mountain areas. Elsewhere, expect scattered showers with light accumulations favoring the mountains and some lower elevations seeing light rain showers from time to time. Steep lapse rates and instability will help drive the convective element and this time of year, the QPF seems to be infiltrated with convective feedback and bullseyes in random areas, so had to dial this back a bit. Throughout this period over the next few days, temperatures should be slowly moderating and trending upwards despite the clouds and showers around. We will see about a 5 degree bump in high temperatures today compared to yesterday and another 5 or so increase for Friday. Highs will still be below normal but will be inching closer to normal by this weekend. && .LONG TERM /FRIDAY NIGHT THROUGH WEDNESDAY/... Issued at 315 AM MDT Thu May 9 2024 Showers will linger over San Juan Mountains and portions of the Sawatch and adjacent valleys Friday night as the low continues to spin over south-central Utah. 00Z/Thu operational models were in good agreement carrying the low over the forecast area Saturday through Sunday morning, moving the system as an open wave over the southern Plains on Sunday. Decent dynamic forcing and steep lapse rates below the 500 mb cold pool is expected to generate widespread shower activity along with some embedded thunderstorms as the system moves overhead Saturday. The mountains and south will be favored but precipitation chances are good for a vast majority of the forecast area. Expect showers to decrease Saturday night as the atmosphere becomes less unstable and dynamic forcing decreases. Despite the low being well east of the area on Sunday, lingering moisture will keep showers in the picture, mainly over the mountains during the afternoon. In fact, even as flow shifts to the northwest and modest drying is indicated in the 700-500 mb layer for the first half of the coming week, diurnally driven showers and thunderstorms can still be expected each day, but coverage will be more scattered. Temperatures will be warming throughout the long term, so mountain snow will largely be confined to areas above 9000 feet with accumulating snow expected to be fairly light and occurring mainly above treeline. Temperatures are expected to be near normal by Saturday then hover from 5 to 10 degrees above normal during the remainder of the period. && .AVIATION /18Z TAFS THROUGH 18Z FRIDAY/... Issued at 1139 AM MDT Thu May 9 2024 VFR conditions are in place with shower activity beginning to expand across the region under daytime heating. If showers move over an airfield temporary ILS/MVFR conditions will be possible through the early evening hours. The best chance of MVFR or below conditions will be in the Gunnison Basin as moisture spills over the higher terrain in the valley. Northeast winds will also be strong at times over the Uinta Basin through the evening with gusts of 25 to 40 mph possible. && .GJT WATCHES/WARNINGS/ADVISORIES... CO...None. UT...None. && $$ SHORT TERM...MDA LONG TERM...NL AVIATION...TGJT