Area Forecast Discussion
Issued by NWS Grand Junction, CO
Issued by NWS Grand Junction, CO
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756 FXUS65 KGJT 140430 AFDGJT Area Forecast Discussion National Weather Service Grand Junction CO 1030 PM MDT Fri Sep 13 2024 .KEY MESSAGES... - Expect dry and warm temperatures Saturday before unsettled conditions return Sunday. - Above normal temperatures persist through Monday before a cold front moving through the region on Tuesday brings cooler than normal readings for the latter part of the week. - Aside from Wednesday, off and on showers can be expected across eastern Utah and western Colorado next week. && .SHORT TERM /THROUGH SATURDAY NIGHT/... Issued at 247 PM MDT Fri Sep 13 2024 Conditions remain quiet tonight and tomorrow with dry, seasonable weather on tap. The most notable forecast feature will be continued hazy skies from across the western CONUS. West/southwesterly flow aloft will continue allow smoke...mostly elevated...to ebb and flow through the forecast period. Limited reduction to visibilities and air quality may result at times. && .LONG TERM /SUNDAY THROUGH FRIDAY/... Issued at 247 PM MDT Fri Sep 13 2024 The weather takes a bit of turn Sunday according to better than average model consensus, as all operational runs depicted a shallow short wave trough lifting northeastward from the Desert Southwest. A shift to a more southerly mid-level trajectory aloft carries mid-level moisture over the region ahead of the trough. The arrival of moisture combined with mid-level vorticity advection and diurnal warming is expected to result in scattered showers and thunderstorms with the southern mountains favored. That won`t be the end of it though, as models remained in good agreement with the next system, which will be digging southward over the West Coast and forming a deep closed low over the Bay Area by 12Z/Monday. This system then moves slowly across the northern Great Basin Monday before lifting to the northern Rockies on Tuesday. During this time, south to southwest flow aloft will continue to feed moisture into the region where broad difluence over the region generates off and on showers across the region with the best chances of precipitation coming Monday and Monday night. Meanwhile, a cold front associated with this system moves eastward across the forecast Tuesday generating breezy/windy prefrontal winds ahead of it. Showers ahead of and along the front combined with falling mid-level temperatures should bring cooler temperatures to the area. Highs are expected to dip below seasonal norms, though the temperature forecast hinges on time of frontal passage so there is some uncertainty with respect to highs on Tuesday. Showers linger into Tuesday evening, but will be shutting down overnight in response to subsidence and diurnal cooling on the back side of the mid-level trough extending southward from the closed low mentioned previously. Drier air in the wake of this system looks likely to deliver a brief break in the action on Wednesday. However, to the West on Wednesday another closed low forms over the western Great Basin and by Thursday this system will be just west of the Green River having evolved into a positive tilt long wave trough extending from the northern High Plains to the southern tip of California. There doesn`t appear to be much moisture for this system to work with, but it does seem reasonable to expect dynamic forcing will be capable of generating some scattered moist convection, with areas north of the I-70 corridor favored. Temperatures for Wednesday and Thursday are expected to remain a bit below normal. && .AVIATION /06Z TAFS THROUGH 06Z SUNDAY/... Issued at 1030 PM MDT Fri Sep 13 2024 Expect mostly clear skies over the next 24 hours with terrain driven winds, becoming breezy at times during the afternoon. VFR conditions will prevail. && .GJT WATCHES/WARNINGS/ADVISORIES... CO...None. UT...None. && $$ SHORT TERM...KAA LONG TERM...NL AVIATION...TGJT