Area Forecast Discussion
Issued by NWS Grand Junction, CO
Issued by NWS Grand Junction, CO
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838 FXUS65 KGJT 112331 AFDGJT Area Forecast Discussion National Weather Service Grand Junction CO 531 PM 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 NIGHT/... Issued at 205 PM MDT Thu Jul 11 2024 The forecast is still on track with little change as the high pressure has currently inched up into southwestern Utah and will continue its slow eastward progression over eastern Utah and Western Colorado by Saturday. With the high moving in temperatures will run five to ten degrees above normal for mid July with lower valleys closer to the ten degrees above normal mark and the mountains and higher elevations a bit cooler nearer the five degrees above normal. Look for the temperatures to warm yet another couple degrees to near record highs tomorrow as the high pressure moves into the region. A Heat Advisory is in effect for the lower valleys of eastern Utah and the Grand Valley in Colorado beginning tomorrow at 10 AM and running through 9 PM Saturday. With the daytime heating, isolated to scattered showers and thunderstorms are beginning to fire again as they have the past few days over the Park and Gore Ranges west to the Flat Tops and south into the central Colorado Mountains with scattered to widespread storms in the San Juans. Convection will quiet down as the sun sets this evening. Models are consistent with a drier airmass pushing into the northern areas Friday to squelch convection along and north of the I-70 corridor. Expect showers and thunderstorms to be more isolated to scattered tomorrow over the southern mountains with the dry push of air. Again, these storms will end around sunset. The primary threats from these showers and thunderstorms will be lightning and outflow gusts of 40-50 mph. && .LONG TERM /SATURDAY THROUGH THURSDAY/... Issued at 205 PM MDT Thu Jul 11 2024 High pressure will be directly overhead by Saturday with a slight nudge eastward by Sunday. This will result in well above normal heat continuing with triple digits easily reached in the lower valleys of eastern Utah and west-central Colorado. The high pressure nudging eastward will allow for a return of sub-tropical moisture to work in from the southwest around the high pressure as mixing ratios take a good bump upwards over the high terrain. This will result in a bit more coverage of showers and thunderstorms over the high terrain. Given the dry low levels, gusty outflow winds look to be the primary concern with any storm activity. The moisture return is not as robust though as the high meanders and doesn`t quite stay east of the region as shortwaves tracking across the Intermountain West and down into the northern Rockies and Plains, this should allow the high pressure area to shift back westward by Wednesday, allowing drier air to infiltrate back in from the northwest. Our best period of increased storm activity appears to be Monday and Tuesday as the forcing from the shortwaves interacts with the moisture in place to result in more coverage of storms and better potential for the lower valleys to see some late in the day. Confidence in this pattern shift as well as coverage of storms is low as models are still trying to figure this out. So, while the details are a bit fuzzy, the overall trend remains the same. Temperatures still look to remain above normal heading into next week, but not quite as hot as lower desert valleys look more like upper 90s to low 100s rather than mid 100s. && .AVIATION /00Z TAFS THROUGH 00Z SATURDAY/... Issued at 531 PM MDT Thu Jul 11 2024 Shower and thunderstorm activity will continue to decrease through sunset with gusty outflow winds the main threat at this time. VFR conditions should persist over the next 24 hours with an almost carbon copy of conditions expected tomorrow. && .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...DB LONG TERM...MDA AVIATION...TGJT