625 FXUS65 KGJT 250904 AFDGJTArea Forecast Discussion National Weather Service Grand Junction CO 304 AM MDT Thu Sep 25 2025
.KEY MESSAGES...
- Warmer and drier conditions continue today before moisture increases from south to north throughout the weekend.
- A prolonged period of active/wet weather is possible this weekend through early next week.
- Moisture spikes Sunday into Monday which coincides with a passing system. Stronger storms with the threat of heavy rain could lead to excess runoff issues especially over recent burn scars.
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.SHORT TERM /THROUGH FRIDAY/... Issued at 303 AM MDT Thu Sep 25 2025
The interaction between the northern and southern streams the next few days and a SubTropical moisture tap looks likely to bring some interesting weather late this week into early next week. Most of the focus will be on a closed low that hand analysis has sitting off the central Cali coast this morning. High pressure remains in control over the Intermountain West and troughing East of the Rockies. A quiet and warm day today will be the last for a while as we begin to introduce moisture to the profile tonight. PWAT looks to double from late this afternoon into Friday afternoon. Driving this moisture advection will be the arrival of the off shore low into Southwest as a northern stream trough moves through and nudges in inland. Isolated nocturnal showers/virga will move into the 4 Corners region overnight on this moisture surge. The bulk of large scale forcing remains upstream of us in the diffluent eastern edge of the cyclone over SoCal. Terrain forcing and weak vorticity advection over the southern and western CWA will help release instability in this moister regime and pop isolated to scattered afternoon convection. Moderate to heavy rainfall rates will be possible in the stronger storms with the biggest threat to the burn scars in the southern Colorado mountians. Temperatures the next few days look to stay near to slightly above normal.
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.LONG TERM /FRIDAY NIGHT THROUGH WEDNESDAY/... Issued at 303 AM MDT Thu Sep 25 2025
On Saturday and Sunday the low will kick out and start lifting over the area. The models are in pretty decent agreement with strength and timing of the wave. Some details still need to get worked out especially if we get any instability. Moisture and forcing should coincide for this round therefore precipitation chances increase. PWAT values during this timeframe range from 150-200 percent of normal, which is modest. Conditions dry out some for early next week, although another could quickly move in from the west.
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.AVIATION /06Z TAFS THROUGH 06Z FRIDAY/... Issued at 1120 PM MDT Wed Sep 24 2025
VFR and light winds prevail the next 24 hours.
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.GJT WATCHES/WARNINGS/ADVISORIES...
CO...None. UT...None.
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SHORT TERM...15 LONG TERM...KJS AVIATION...TGJT
NWS GJT Office Area Forecast Discussion