Area Forecast Discussion
Issued by NWS Grand Junction, CO
Issued by NWS Grand Junction, CO
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163 FXUS65 KGJT 242036 AFDGJT Area Forecast Discussion National Weather Service Grand Junction CO 236 PM MDT Fri May 24 2024 .KEY MESSAGES... - The potential for showers and storms increases this evening and continuing through tomorrow. Gusty winds will be possible with these showers and storms. - Mountain snow is possible generally above 9 kft with the impacts to the roads occurring tonight and tomorrow night. Highest chances for upwards of several inches of snow will be in the northern and central mountains. - Temperatures will run below normal through the weekend then increase next week. Precipitation chances remain low through mid week. && .SHORT TERM /THROUGH SATURDAY NIGHT/... Issued at 236 PM MDT Fri May 24 2024 A trough of low pressure continues to approach from the west this afternoon, dragging through the Great Basin this evening. A modest uptick in midlevel moisture paired with a weak ripple embedded in the southwest flow aloft has led to the development of isolated showers in the last few hours, focused north of I-70. Persistent dry air in the lower levels, as noted in our 12Z sounding at GJT, has mainly resulted in virga showers which has enhanced winds at the surface. The Eagle Airport reported a peak gust of 38 mph. Outside of these high-based showers there`s been an increase in mid and high clouds across the northern two-thirds of the forecast area while the Four Corners region remains mostly sunny. As a result, some occasional gusts down south of 30 to 35 mph will be possible through this evening. The trough digs into western Utah tonight before it lifts across western Colorado and eastern Utah on Saturday. Broad scale ascent becomes maximized during the 12Z - 18Z timeframe on Saturday with the best shower coverage expected across mainly the north as a result before activity becomes more convective in nature Saturday afternoon. CAM guidance is pinging on a notable band of showers extending from Baggs, WY to the Tavaputs Plateau mid Saturday morning as the weak cold front associated with this system begins to dig into the region. Snow levels will drive down to 9-10kft with the front so previous forecasts of upwards of several inches of snow remains likely. As the cold front works farther southeast throughout the day showers and storms will reach south of I-70 with storms becoming capable of producing gusty outflow winds and perhaps some graupel or small hail. Elsewhere outside of Saturday`s shower activity will be dry under partly sunny skies. The trough axis slides east of the Divide on Saturday evening with showers tapering off from west to east in response. && .LONG TERM /SUNDAY THROUGH THURSDAY/... Issued at 236 PM MDT Fri May 24 2024 Showers rapidly diminish west to east Sunday morning under subsidence as ridging moves in from the west behind the trough/frontal boundary moving out onto the Plains. Sunday afternoon will see some lingering scattered showers over the northern Colorado mountains with isolated showers in the central mountains ending by evening. Temperatures Sunday will run a little below normal under a northwesterly flow. Monday into the middle of the week looks to be mostly quiet with the ridge and mostly clear skies moving in overhead, and temperatures rising to five to ten degrees above normal for late May. Winds will be light terrain driven through the period with the weak westerly flow aloft. Weak lower level south to southeasterly flow along the Front Range may be enough to push some moisture up to the Divide to feed a few isolated showers along the Divide each afternoon, in the southern mountains Monday, spreading north into the central and northern mountains Tuesday and Wednesday. In the latter half of the week, models concur on a low pressure system dropping into the Pacific Northwest pushing the ridge east out onto the Plains and putting eastern Utah and Western Colorado under an increased southwesterly flow aloft and gusty southwesterly afternoon winds at the surface. Models diverge on how deep they dig the associated trough into the Great Basin much as they have with the last few troughing systems. With the last system, the solutions that forecast the deeper trough were the better forecasts that brought a cold shot of northern air to the region with temperatures well below normal. Current guidance is keeping the system more to the north with unsettled weather in the northern mountains and temperatures near normal, which is reasonable for the end of May, but we can`t rule out another deep trough to the west and a cold shot dropping temperatures ten degrees by the end of the week with unsettled weather spreading south into the central and even southern mountains. The ensembles indicate wide dispersion in the solutions mid-week and beyond expressing the low confidence in the forecast for the latter half of the week, so you`ll just need to stay tuned for updates on the extended period to see how this plays out. && .AVIATION /18Z TAFS THROUGH 18Z SATURDAY/... Issued at 1124 AM MDT Fri May 24 2024 Expect VFR conditions with increasing clouds ahead of the next system through the next 24 hours. Look for isolated to scattered showers to move in from the northwest overnight becoming scattered along and north of the I-70 corridor after about 15Z. Included vicinity showers from KCNY and KASE northward late in the TAF period with showers becoming predominant at KVEL after 16Z. Conditions will remain above ILS breakpoints through the TAF period. && .GJT WATCHES/WARNINGS/ADVISORIES... CO...None. UT...None. && $$ SHORT TERM...MMS LONG TERM...DB AVIATION...DB