298 FXUS65 KGJT 171736 AFDGJTArea Forecast Discussion National Weather Service Grand Junction CO 1136 AM MDT Wed Sep 17 2025
.KEY MESSAGES...
- Showers and storms develop over the higher terrain along and north of I-70 during the afternoon today.
- Temperatures will be below normal before a warmup kicks in towards the end of the week.
- Moisture returns this weekend but confidence in the extent and timing remains low at this time.
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.SHORT TERM /THROUGH THURSDAY/... Issued at 117 AM MDT Wed Sep 17 2025
Precipitation has ended across the region as the nearby low pressure system continues to move east of the Rockies, as shown by satellite imagery. Showers and thunderstorms are possible today, primarily north of I-70, where moisture lingers and a lobe of energy off of the low pressure system moves through. Overnight Wednesday into Thursday flow will shift to dry and northerly, keeping PoPs near zero Thursday afternoon while PWATs drop to 50-75% of normal across the CWA. High temperatures stay below normal through the short term before a warmup later this week.
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.LONG TERM /THURSDAY NIGHT THROUGH TUESDAY/... Issued at 117 AM MDT Wed Sep 17 2025
A ridge of high pressure will be over the CWA at the start of the long term period but will start shifting east as a shortwave approaches from the southwest. Southwesterly flow ahead of the shortwave will allow moisture to increase down south before spreading across the entire CWA by late Friday night. While moisture will increase, ensembles are indicating the shortwave will lose much of its characteristics and this will allow a few showers, maybe a quick storm to fire over SE Utah and the southern valleys Friday but not much else is expected. Residual moisture will linger across the area Saturday and Sunday and will be worked on by a couple of weak waves through the weekend bringing some isolated showers/storms to the northern half of the CWA. After that, a broad area of high pressure sets up across the desert southwest which will bring plenty of sunny skies and warm temperatures to the region.
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.AVIATION /18Z TAFS THROUGH 18Z THURSDAY/... Issued at 1131 AM MDT Wed Sep 17 2025
A weak disturbance sweeps across northern Colorado this afternoon. This will bring a few mid and upper level clouds to the region, but little else. Kept TSRA language in KASE and KEGE, although very weak chances there. KHDN is more likely to see some showers develop on nearby terrain and some TEMPO ceiling, TSRA impacts. VFR conditions will prevail elsewhere across the region, including areas with showers this evening and beyond.
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.GJT WATCHES/WARNINGS/ADVISORIES...
CO...None. UT...None.
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SHORT TERM...GF LONG TERM...TGR AVIATION...TGJT
NWS GJT Office Area Forecast Discussion