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Area Forecast Discussion
Issued by NWS Grand Junction, CO
Issued by NWS Grand Junction, CO
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908 FXUS65 KGJT 171139 AFDGJT Area Forecast Discussion National Weather Service Grand Junction CO 539 AM MDT Wed Jul 17 2024 .KEY MESSAGES... - Temperatures are expected to remain a few degrees above normal with daily thunderstorm chances through the remainder of the week and into the weekend as moisture is recycled under the area of high pressure over the region. - Threats from thunderstorms will mainly be from gusty outflow winds though a few storms will be capable of producing smaller hail and moderate to heavy rainfall rates. Overall flooding threats remain low. - The combination of high based storms, gusty outflow winds and lightning will keep also keep a threat of new wildfire starts in the picture. && .SHORT TERM /THROUGH THURSDAY/... Issued at 309 AM MDT Wed Jul 17 2024 High pressure remains south of the forecast area today leaving the region under westerly flow aloft. Models were consistent in predicting a roughly 0.2" decrease in precipitable water over the area as flow taps into drier air to west. As a result, expecting fewer storms over eastern Utah and the western border zones of Colorado this afternoon and evening. In contrast, expect scattered to numerous showers and thunderstorms along the Continental Divide and adjacent valleys again today. The main threat from these storms will be lightning, small hail and gusty outflow winds. Localized heavy rain is possible, mainly in the eastern San Juan Mountains. Meanwhile, drying will allow temperatures to rise by 3 to 5 degrees for most of the forecast area. The exception will be in the San Juan Mountains where storms will be more numerous with some of this activity spreading southeastward across lower elevations from Durango eastward to Pagosa Springs. Increased clouds and showers in these areas are expected to result in a few degrees of cooling. Expect the usual downturn in moist convection during the evening in response to diurnal cooling. The high begins to shift westward on Thursday and at the same time, moisture levels begin to rise again, especially across the south. Consequently, expect showers and thunderstorms to increase in coverage which will be most noticeable in eastern Utah and far western Colorado after today`s downturn in activity. Storm characteristics will be similar to today with a slight uptick in the potential for heavy in southwest Colorado. Temperatures are expected to continue to cool over the southern zones while increasing across the north. && .LONG TERM /THURSDAY NIGHT THROUGH TUESDAY/... Issued at 309 AM MDT Wed Jul 17 2024 With deep lows over the Gulf of Alaska and the Hudson Bay, and strong ridging over the Western States in a blocking pattern, expect little change in the weather across eastern Utah and Western Colorado through the extended forecast period. Thursday evening, the high that has been dominating our weather will be centered over northern Arizona slowly working its way into the Great Basin by Saturday where it sets up camp. This will bring near record temperatures to much of the Intermountain West, but being only on the eastern fringes of this high, temperatures across the region will remain near normal through next Tuesday. The moist surge of monsoonal moisture continues Friday with widely scattered showers and thunderstorms across the higher terrain along and north of the I- 70 corridor, more widespread through the central and southern Colorado mountains. As the high settles into the Great Basin Saturday into next week, drier air moves into the northern areas to limit convection to isolated showers and thunderstorms each afternoon and evening along and north of the I-70 corridor while widely scattered storms continue through the central and southern mountains. && .AVIATION /12Z TAFS THROUGH 12Z THURSDAY/... Issued at 539 AM MDT Wed Jul 17 2024 Fog and low clouds generated by the gypsum plant near KEGE has brought ceilings and visibility bordering between MVFR and IFR levels. Expect this will rapidly dissipate once the sun comes up. Elsewhere and during the remainder of the period, moderately drier air filters into the region from the west today resulting in decreased showers and thunderstorms. As a result, VFR conditions are expected at all TAF sites through the next 24 hours with no ceilings below ILS breakpoints. Expect light and terrain driven winds, except in the vicinity of showers/storms where gusts to 45 kts are possible. && .GJT WATCHES/WARNINGS/ADVISORIES... CO...None. UT...None. && $$ SHORT TERM...NL LONG TERM...DB AVIATION...NL