Area Forecast Discussion
Issued by NWS Grand Junction, CO
Issued by NWS Grand Junction, CO
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804 FXUS65 KGJT 111747 AFDGJT Area Forecast Discussion National Weather Service Grand Junction CO 1147 AM MDT Thu Jul 11 2024 .KEY MESSAGES... - Temperatures will continue to climb into the weekend. Near record highs are expected Friday and Saturday. - Afternoon showers and thunderstorms will develop over higher terrain each day throughout the next 7 days with an increase in coverage expected early next week. - Temperatures remain elevated beyond the weekend, but some relief is expected from cloud cover and shower activity, as monsoonal moisture is forecast to return early next week. && .SHORT TERM /THROUGH FRIDAY/... Issued at 124 AM MDT Thu Jul 11 2024 There is not much change in the overall pattern today compared to yesterday. The Great Basin high pressure continues to gradually shift eastward so highs will come up and degree or two. There may be a subtle drying to the environment due to that shift as well, but not sure it will translate to much difference. Still expect showers and storms to develop over the high terrain across the eastern half of the area this afternoon. They will be capable of producing wind gusts up to 45 mph as outflows expand and fan out after development. Some of the stronger cells may produce small hail in spots. Motion will be north to south once again. By sunset this activity will dissipate. Lows increase tonight by a few degrees. Tomorrow the high pressure begins to drift over Utah causing yet another increase in temperatures by a few degrees. In fact, we may break some records as the high pressure gets closer and eventually settles overhead. The high will advect some drier into the northern mountains tomorrow so expect less afternoon convection there. Diurnal showers and storms will still develop mainly south of I-70 where moisture stays sufficient. Once again small hail is possible and gusty outflow winds are likely. && .LONG TERM /FRIDAY NIGHT THROUGH WEDNESDAY/... Issued at 124 AM MDT Thu Jul 11 2024 High pressure continues to drive the forecast for the foreseeable future. This means above-normal temperatures are here to stay, especially this weekend when triple-digit highs will be commonplace in the valleys. On Saturday moisture is progged to be highest in the southern mountains where the highest coverage of precipitation is expected, but there may be enough moisture present to kick off terrain-driven showers and storms further north as well. We continue to see diurnal precipitation chances in the high terrain through the forecast period. Coverage will likely increase on Monday as more moisture begins to wrap around the high pressure center and into eastern Utah and western Colorado. The GEFS and ECMWF ENS show this increased mositure (125-150% of normal) sticking around through midweek. Outflows could help initiate precipitation in the valleys as well, but confidence in the location and coverage of outflow- driven showers and storms is rather low at this time. Beyond midweek we begin to see model guidance diverge. We will have to wait and see how synoptic features across the CONUS develop and impact what happens to the location of the high and the moisture feed into the region. && .AVIATION /18Z TAFS THROUGH 18Z FRIDAY/... Issued at 1144 AM MDT Thu Jul 11 2024 Isolated showers and thunderstorms are expected to develop across the higher terrain of western Colorado this afternoon with gusty outflow winds 35 to 45 mph possible at times. Aside from high terrain storms, VFR conditions are expected to persist through the period. && .GJT WATCHES/WARNINGS/ADVISORIES... CO...Heat Advisory from 10 AM Friday to 9 PM MDT Saturday for COZ006. UT...Heat Advisory from 10 AM Friday to 9 PM MDT Saturday for UTZ024-027-029. && $$ SHORT TERM...KJS LONG TERM...KAA AVIATION...MDA