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Area Forecast Discussion
Issued by NWS Grand Junction, CO
Issued by NWS Grand Junction, CO
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643 FXUS65 KGJT 152352 AFDGJT Area Forecast Discussion National Weather Service Grand Junction CO 552 PM MDT Thu Aug 15 2024 .KEY MESSAGES... - Tranquil conditions remain in place this evening and through Friday. - Monsoonal moisture returns showers Saturday, mostly in eastern Utah and along the Colorado state line. - More robust monsoonal moisture will impact the region Sunday and beyond. Showers and thunderstorms will bring back the threat of localized flooding Sunday and into the new work week. && .SHORT TERM /THROUGH FRIDAY/... Issued at 237 PM MDT Thu Aug 15 2024 Drier conditions under a transitory ridge have brought a pause to the monsoonal shower activity across the region. Lower relative humidities and waning August sunlight are also finding morning lows trending down on the mountains, which is helping morning drainage winds return some cooler air to the valleys as well. Afternoon highs will hover around the climatological average through tomorrow, with a slight warming trend heading into the weekend. For now, the near term looks to remain mostly dry with scattered cumulus clouds popping on the terrain features today and tomorrow. Enough remnant moisture remains in the mountains to see an isolated shower or two in northern Colorado and perhaps south along the Continental Divide of the Central Mountains. Winds turn more southwesterly Friday afternoon ahead of an approaching low coming ashore in the PACNW. Breezy conditions are expected along the Wyoming border of the CWA. Our northern counties will see some of the stronger winds aloft mix down Friday afternoon, with wind gusts around 20 mph expected. Desert valleys will surge into the middle and upper 90`s, while up the hill, 80`s and 70`s can be expected Friday. Available moisture is expected to be in shorter supply tomorrow and should produce another quiet day on the West Slope, after another cool morning. && .LONG TERM /FRIDAY NIGHT THROUGH THURSDAY/... Issued at 237 PM MDT Thu Aug 15 2024 By Saturday, the high pressure that has been over the Desert Southwest blocking the monsoonal moisture will have slid to the east over West Texas as a deep cold low drops down off the coast of the Pacific Northwest. This sets up a weak omega-ish blocking pattern across the CONUS with the troughing pattern over the eastern United States that models, ensembles and otherwise, are in agreement will last at least through the coming week to hold the door open to a moderate monsoonal flow up off the Gulf of California through Arizona into eastern Utah and Western Colorado. This will boost PWAT`s from 0.3-0.4 inches on Friday up to 0.7-0.9 inches Saturday and 0.8 to 1.2 inches Sunday through much of next week. Given these conditions, expect isolated to scattered showers and thunderstorms over the higher terrain Saturday afternoon and evening. Sunday and Monday, coverage will be widely scattered to widespread over the higher terrain of the region with isolated to scattered storms moving off the terrain over the lower valleys through the afternoon and evening. These storms may produce periods of heavy rain and, with a weak flow aloft, may lead to flash flooding risks due to slow moving and/or training storms. By mid week, the high builds over New Mexico to reduce the monsoonal flow somewhat with the afternoon and evening storm coverage backing off to widely scattered across the region, but the risks for flash flooding will continue. Temperatures will be about five degrees above normal Saturday, but will drop to near normal Sunday into next week with more cloud cover and increased shower activity. Mid week looks to warm back to about five degrees above normal with morning skies clearing out allowing stronger diurnal heating. && .AVIATION /00Z TAFS THROUGH 00Z SATURDAY/... Issued at 545 PM MDT Thu Aug 15 2024 VFR conditions are forecast through the TAF period. Generally light, terrain driven winds across the region through forecast with occasional gusts up to 20 knots tomorrow afternoon. && .GJT WATCHES/WARNINGS/ADVISORIES... CO...None. UT...None. && $$ SHORT TERM...LTB LONG TERM...DB AVIATION...KAA