


Area Forecast Discussion
Issued by NWS Grand Junction, CO
Issued by NWS Grand Junction, CO
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456 FXUS65 KGJT 131042 AFDGJT Area Forecast Discussion National Weather Service Grand Junction CO 442 AM MDT Sun Jul 13 2025 .KEY MESSAGES... - Temperatures increase today across the region. Afternoon thunderstorms develop along the Divide favoring the San Juans. - Coverage of afternoon showers and storms will gradually increase as the week wears on. - Outflow winds and dry lightning remain a threat today and tomorrow, as thunderstorm chances spread across additional terrain. && .SHORT TERM /THROUGH MONDAY/... Issued at 434 AM MDT Sun Jul 13 2025 Northwesterly flow continues to spill across the front side of high pressure anchored over the Southwest this morning. A shot of cloud cover passed over southwest Colorado during the overnight hours, delivering a brief bit of rain to Pagosa Springs. I suspect it might have evaporated before anyone wakes up to this discussion. Afternoon heating will bump up isoheights and shift the high eastward as expected. This should open the door for a weak plume of moisture to drift northward along the Divide. Thunderstorm chances will spread northward today along this moisture including the San Juans, Central and Northern Mountains. Wetting rain will still be hard to come by thanks to the persistent dry lower atmosphere. Thus, gusty outflow winds and dry lightning remain a threat again today. Unfortunately, this will come as bad news for those hoping for relief from local wildfires. Afternoon heating is expected to fan more smoke to the region as well. High res smoke forecasts keep the densest smoke across southwest Colorado and southeast Utah today. While dense smoke will remain confined to areas immediately downwind of fires, some smoke will remain visible to much of the CWA for the foreseeable future. Temperatures will notch upward today and tomorrow too, as we likely crest the 100 degree mark again here in the Grand Valley. Utah deserts are expected to push well past that mark again today too. Deterministic models are keen to keep this air mass in place, which means temperature relief is unlikely until we can get some cloud cover and rainfall mixing down some cooler air. The bigger longwave pattern offers no help either, keeping frontal activity well to the north this week. Monday looks like a rinse and repeat of today as additional moisture bubbles beneath the high along the southern Divide. Up north, a weak clipper system does offer some additional moisture Monday afternoon. This will increase thunderstorm coverage on regional terrain, thereby increasing the dry lightning and outflow wind threat. Hot and dry July continues. && .LONG TERM /MONDAY NIGHT THROUGH SATURDAY/... Issued at 356 PM MDT Sat Jul 12 2025 The synoptic pattern really doesn`t change much through the seven-day forecast with high pressure being the driving force behind much of our weather for the week to come. We`ll be following two main storylines throughout much of the upcoming week. 1. Unseasonably Warm Temperatures Temperatures remain 5-10 degrees above normal for mid-July through at least mid week. At that time, a shortwave trough is progged to move track across the Pacific Northwest into the Northern Plains. Locally, this wave will flatten out the ridge overhead and could help temperatures cool off a few degrees. Despite this, the current forecast calls for normal to above- normal temperatures through the work week. 2. Increasing Moisture Global ensembles continue to show signs of moisture slowly seeping back into the region, first along the Divide from the southeast, then from the north as the aformentioned shortwave leads to zonal flow aloft, and then from the south once more late in the period. PWAT anomalies of 100-125% of normal will not support the widespread rains we need, but will support convection over the high terrain each afternoon. Storms will continue to be capable of producing gusty outflow winds, fire starts, and small hail at times. There are hints of stronger moisture advection late in the week/next weekend, but it is still too early to tell if this will be the pattern that ushers in the monsoon. There`s too much spread between global ensembles to have much forecast confidence come next weekend. && .AVIATION /06Z TAFS THROUGH 06Z MONDAY/... Issued at 1136 PM MDT Sat Jul 12 2025 VFR conditions will continue in the overnight hours with some high cloud cover thinning out to clear skies by morning for southwest Colorado. Smoke will continue to spread southward Sunday from the highway 50 corridor thanks to area wildfires. Don`t expect significant reductions in visibility, but its presence will certainly be noticed. Shower activity picks up on the terrain near the Divide Sunday afternoon. PROB30 TSRA is included in KASE, KGUC, and KTEX. Also kept VCSH in KEGE. Gusty outflow winds and lightning will pose the primary threat to aviators near storms. Some lingering cloud cover on the terrain will likely stick around Sunday evening to close out this TAF period. && .GJT WATCHES/WARNINGS/ADVISORIES... CO...None. UT...None. && $$ SHORT TERM...LTB LONG TERM...KAA AVIATION...TGJT