FXUS65 KGJT 091132 AFDGJT Area Forecast Discussion National Weather Service Grand Junction CO 532 AM MDT Fri May 9 2025 .KEY MESSAGES... - Daily afternoon showers and thunderstorms will develop over the higher terrain capable of producing gusty outflow winds, moderate to heavy rainfall rates, and small hail at times. - Unseasonably warm temperatures remain in place through the weekend into early next week. && .SHORT TERM /THROUGH TONIGHT/... Issued at 357 AM MDT Fri May 9 2025 Today's forecast is a rinse and repeat of yesterday's, just a handful of degrees warmer. With high pressure continuing to build over the region, today's highs are expected to be 5 to 10 degrees above seasonal normals with the lower valleys warming into the 80s. Sufficient moisture remains in place to support convection from daytime heating, mainly over the higher terrain. Gusty outflow winds and lightning are the primary threats of thunderstorms that develop this afternoon. && .LONG TERM /SATURDAY THROUGH THURSDAY/... Issued at 302 PM MDT Thu May 8 2025 On Saturday the axis of a broad ridge stretching across the West will be passing over our area. Warm air advection occurring while we are under the ridge will raise high temperatures to well above normal until mid next week. Saturday and Sunday will be the warmest days of the long term, with high temperatures 5 to 15 degrees above normal possible. After Monday temperatures will begin to drop below normal as cooler air moves in with an approaching trough. With ridging aloft through the middle of next week, widespread precipitation is not in the forecast through the long term. Model guidance is suggesting a trough moving inland from the Pacific Northwest on Monday. Some models seem to keep most of the impacts from this trough primarily to the north of our CWA, but this far out in time confidence in this guidance is low. Although widespread precipitation is not in the forecast while ridging is aloft, afternoon convection is possible in the mountains each day through the weekend while daytime heating couples with lingering moisture. PWATs stay around 125-150% of normal through early next week, although at times it may exceed or fall below this range. Gusty afternoon winds are possible on Monday and Tuesday as the trough from the Pacific Northwest approaches our region, bringing a tightening pressure gradient and increased windspeeds aloft. This, in addition to drier air moving in Monday, could cause concerns for fire weather. && .AVIATION /12Z TAFS THROUGH 12Z SATURDAY/... Issued at 531 AM MDT Fri May 9 2025 Isolated to scattered showers and storms develop this afternoon over the higher terrain. Gusty outflow winds may impact some of our mountain airports from time to time, otherwise confidence is low for impacts at the terminals. Elsewhere, VFR conditions are forecast through the TAF period. && .HYDROLOGY... Issued at 221 PM MDT Thu May 8 2025 Warm temperatures and potential for rain-on-snow at mid to high elevations (8500' to 10000') increase the risk of areal flooding and elevated streamflows due to rapid snowmelt. Forecast temperatures extending through the weekend are expected to exceed 5 to 15 degrees above normal for early May, such that highs range in the 60's to 70's across mid to high elevations. In addition, isolated to scattered afternoon showers and thunderstorms are possible over higher terrain along the Divide each afternoon, with precipitation potentially falling as rain as high as 10,000'. Streams and tributaries across the San Juan's and along the Continental Divide over central Colorado are most susceptible to see the effects of warming and potential rain-on-snow accelerating snowmelt and elevating flows. As a result, low-lying areas and valley floors across said terrain could see some minor inundation from snowmelt. Stay away from fast moving water, exercise caution near riverbanks and stay alert to watches and warnings from the National Weather Service. && .GJT WATCHES/WARNINGS/ADVISORIES... CO...None. UT...None. && $$ SHORT TERM...KAA LONG TERM...GF AVIATION...TGJT HYDROLOGY...ERW