Area Forecast Discussion
Issued by NWS Grand Junction, CO
Issued by NWS Grand Junction, CO
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689 FXUS65 KGJT 162117 AFDGJT Area Forecast Discussion National Weather Service Grand Junction CO 317 PM MDT Tue Jul 16 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 WEDNESDAY NIGHT/... Issued at 317 PM MDT Tue Jul 16 2024 The SubTropical High will start to get a nudge back to the West over the next 24 hours as low pressure digs through OH/TN Valleys. This minor switch in West to Northwest flow will pull in some drier air and it appears there will be a bit of a downturn in convection for tomorrow. That said...this drier air has been working into northern Utah and Colorado this afternoon but there is plenty of convection thanks to a moderate shear profile. The convective mode has remained multicell but a few of the storms have been strong enough to throw out some accumulating hail and modest to heavy rainfall rates. Overall however gusty outflow winds remain the main threat past sunset before a noticeable downturn in convection is indicated by most models. The only caveat...PVU fields/current H2O imagery show a wave moving through SW Utah attm which is triggering storms to our West and this moves through overnight. Will the drying trend counter this wave and keep things on the quiet side likely not so there are some minimal pops on place. Maybe not enough. Otherwise most of the convection looks to favor the eastern high country of our CWA on Wednesday with a few storms also favored again over the northern Utah mountains. With a drier sounding the threat of storms with more wind and lightning than rainfall will be the favored mode. Cloud cover will continue to dictate overnight temperatures but the trend is a bit cooler tonight with drier conditions forecast. Temperatures tomorrow remain above normal and could gain a degree or two with more sunshine in place. && .LONG TERM /THURSDAY THROUGH MONDAY/... Issued at 317 PM MDT Tue Jul 16 2024 The stubborn ridge of high pressure baking the West still shows no signs of abating in the near term outlooks. Troughing in the north Pacific and eastern Canada sandwich a persistent hot air mass here in the West. Forecast challenges still exist for the coming days, as pockets of monsoonal moisture work their way northward under the ridge. Temperatures in our low valleys along the Utah/Colorado state line will hover around 100 degrees, with a few spikes likely when cloudless conditions allow. Elsewhere, lows and highs will run around 5 degrees warmer than climatology through the period. Temperature relief for many locales will come by way of afternoon showers and thunderstorms. Storm coverage will continue to favor the terrain, with model data showing some contraction of coverage towards the weekend. Confidence in storm coverage is low. Outdoor enthusiasts on the higher terrain will want to keep an eye to the sky, as lightning will be a daily hazard this week. Strong outflow winds and small hail will remain a concern as well. Saturday, models begin to pinch off a clipper system dropping into the Plains that threatens the ridge and knocks heights down. This could potentially push our monsoonal tap out of the way. At the moment, I`d say our northern counties see a break in storms this weekend if we get into the expected drier northerly flow. This could push temperatures down a bit for much of the eastern half of the CWA, while areas closer to the remnant ridge out west will stay hot. This remains a tentative forecast as models try to signal a pattern shift. For now, it looks like a pattern shift on Monday and Tuesday to close out the long term. && .AVIATION /18Z TAFS THROUGH 18Z WEDNESDAY/... Issued at 1123 AM MDT Tue Jul 16 2024 Thunderstorm activity is beginning to increase and will be isolated to scattered across the region this afternoon and evening. Limited coverage over most areas reduces confidence in impacts at most TAF sites where VCTS was used...with more confidence at KTEX...KVEL and KGUC looking at the latest radar and webcam trends. However most TAF sites have some probability of seeing gusty winds from nearby storms or from more organized outflow boundaries from farther storm complexes. Will amened TAF sites as these threats become more apparent from radar/satellite trends. Otherwise VFR should hold over the next 24 hours. && .GJT WATCHES/WARNINGS/ADVISORIES... CO...None. UT...None. && $$ SHORT TERM...15 LONG TERM...LTB AVIATION...TGJT