Area Forecast Discussion
Issued by NWS Grand Junction, CO
Issued by NWS Grand Junction, CO
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226 FXUS65 KGJT 281725 AFDGJT Area Forecast Discussion National Weather Service Grand Junction CO 1125 AM MDT Tue May 28 2024 .KEY MESSAGES... - Conditions mainly dry and breezy, with chances for isolated to scattered showers and thunderstorms over the higher terrain each afternoon/evening throughout the week and into early next week. - Aside from a brief dip to near normal temperatures Thursday, expect above normal warmth this week. && .SHORT TERM /THROUGH WEDNESDAY/... Issued at 313 AM MDT Tue May 28 2024 A mid-level ridge moved over the Rockies during the night, but its axis will shift east of the Continental Divide this afternoon as an eastern Pacific trough approaches the West Coast. This allows modest levels of moisture in the 700 to 500 mb layer to spread north which, when combined with daytime warming, is expected to generate another round of isolated to low end scattered showers and thunderstorms this afternoon. However, this activity will also include the central and northern ranges in addition to the San Juan Mountains. In the absence of dynamic forcing, diurnal cooling will bring an early end to moist convection this evening. On Wednesday, flow aloft increases from the southwest as the trough to the west sweeps across the Great Basin driving a cold front to northeast Utah late in the afternoon. This strengthens the pressure gradient at the surface and aloft resulting in moderately breezy conditions, especially across the north. Models indicated little moisture entrained in the southwesterlies, so expect another round of isolated/low end scattered shower/thunderstorm activity Wednesday afternoon, mainly driven by instability. Temperatures continue to rise today with afternoon highs on average 5 degrees above normal with a degree or two of warming indicated for Wednesday. && .LONG TERM /WEDNESDAY NIGHT THROUGH MONDAY/... Issued at 313 AM MDT Tue May 28 2024 Wednesday evening the low will be slowly tracking east across northern Alberta with the associated trough extending southeastern Utah and western Colorado. With the subtropical leaf of the jet well to the south over northern Mexico and little organization of the polar jet over the Rocky Mountains from Canada to Arizona and New Mexico, no real activity accompanies this trough. The region can expect generally isolated showers and thunderstorms over the mountainous terrain mostly due to diurnal heating and orographic lift favoring the western slopes of rising terrain under the zonal flow in the base of the trough with the best chances along the Divide. With the low`s slow eastward progression, troughing remains across the northern states through the remainder of the week keeping eastern Utah and western Colorado under a generally dry zonal flow aloft. This favors mostly clear skies, low humidity, and warm temperatures, around five degrees above normal, punctuated by afternoon scattered clouds and isolated mountain showers and thunderstorms. Weak upper-level disturbances pass Saturday and again Sunday with little impact to the region, but will spin up stronger storms as they move out onto the Plains. As the low settles in over the Hudson Bay early next week, strong ridging starts building in over the Intermountain West bringing an extended period of very warm and dry weather. && .AVIATION /18Z TAFS THROUGH 18Z WEDNESDAY/... Issued at 1123 AM MDT Tue May 28 2024 Skies will be mostly clear and winds light and terrain driven for the majority of the next 24 hours, with VFR conditions prevailing. Showers and storms are forming over the higher terrain and will drift over adjacent valleys as the day wears on, so have included VCTS in several TAFs to account for this. These showers will bring mainly lowered ceilings and gusty, erratic winds. && .GJT WATCHES/WARNINGS/ADVISORIES... CO...None. UT...None. && $$ SHORT TERM...NL LONG TERM...DB AVIATION...TGJT