Area Forecast Discussion
Issued by NWS Grand Junction, CO
Issued by NWS Grand Junction, CO
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026 FXUS65 KGJT 141724 AFDGJT Area Forecast Discussion National Weather Service Grand Junction CO 1124 AM MDT Sun Jul 14 2024 .KEY MESSAGES... - The desert valleys of eastern Utah and the Grand Valley in western Colorado remains hot today with temperatures well above normal. Heat Advisories remain in place. - An uptick in thunderstorm coverage this afternoon will lead to an elevated risk of fire starts. A Red Flag Warning has been issued for locations forecast to see the highest storm coverage. - Temperatures remain seasonably warm with daily thunderstorm chances through the seven day forecast. && .UPDATE... Issued at 1010 AM MDT Sun Jul 14 2024 Based on latest model guidance and expected coverage area of dry thunderstorms, decided to add UT487 and CO290 to the Red Flag Warning for dry thunderstorms today. The remaining areas, coverage remains isolated so did not include them in the Red Flag Warning (need at least widely scattered). && .SHORT TERM /THROUGH MONDAY/... Issued at 403 AM MDT Sun Jul 14 2024 Water vapor satellite imagery early this morning showed the high pressure system that has been responsible for the recent stretch of unseasonably warm, dry conditions was located near the central Colorado/New Mexico border. Increasing moisture was also apparent across eastern Utah into western Colorado. Hi-res guidance shows that PWAT values will gradually increase to 0.75-1" by early this afternoon providing the first push of mositure into the region in awhile. Despite more cloud cover today, temperatures are still forecast to be 5 to 10 degrees warmer than seasonal normals. A Heat Advisory remains in effect for the lower valleys until 9 PM this evening. Temperatures cool slightly to kick off the new work week on Monday, but some valley locations will still be flirting with triple- digit highs. Thunderstorm coverage in the mountains will also increase this afternoon with renewed moisture present. Model soundings show that precipitation will be fighting a very dry near-surface layer across much of the forecast area. This means the threat for heavy rainfall is on the lower side, but conditions will be favorable for gusty outflow winds up to 50 mph. Frequent lightning will also pose an elevated threat for fire starts given the very dry antecedent conditions. Sensible weather conditions will be somewhat of a rinse and repeat on Monday afternoon with more showers and storms rotating around the high overhead. && .LONG TERM /MONDAY NIGHT THROUGH SATURDAY/... Issued at 403 AM MDT Sun Jul 14 2024 High pressure remains centered south of the forecast area somewhere over the central border between New Mexico and Arizona Monday night where it will remain on Tuesday through Tuesday night. Moisture levels appeared largely unchanged in model data, so diurnal shower/thunderstorm on Tuesday should be similarly to Monday`s activity. Positioning of the high brings modest drying in westerly flow aloft for Wednesday resulting in reduced moist convection over eastern Utah and westernmost Colorado, while the mountains of the Continental Divide remain active. The downturn in activity will be short lived as moisture pooled over the southern Plains is wrapped back into the region by Thursday which is then recycled over the area through the end of the week as the high slowly shifts west. Moisture levels stay below 150% of normal through the period, so expect excessive rainfall will be localized. Despite, the persistent shower/thunderstorm activity, temperatures will continue to run above normal, though aren`t likely to be as hot as they have been over the past several days. && .AVIATION /18Z TAFS THROUGH 18Z MONDAY/... Issued at 1120 AM MDT Sun Jul 14 2024 Expect afternoon thunderstorms near mountain TAFs this afternoon, with VCTS most likely for KTEX, KGUC, KASE, and KEGE. Minimal rain is anticipated with said storms, thus, lightning and gusty outflow winds are the main impacts to nearby terminals. Elsewhere, VFR conditions will prevail over the next 24 hours with passing mid to high level clouds. && .FIRE WEATHER... Issued at 1010 AM MDT Sun Jul 14 2024 The mix of dry fuels, a dry airmass near the surface, and an upturn in thunderstorm coverage in the higher terrain will lead to an elevated threat for dry thunderstorm fire starts this afternoon. As a result, a Red Flag Warning has been issued for locations most susceptible and where thunderstorm coverage is at least widely scattered. However, any lightning strike could lead to fire starts. While environmental winds are forecast to be on the lighter side with high pressure overhead, gusty outflow winds up to 50 mph are possible near showers and storms. && .GJT WATCHES/WARNINGS/ADVISORIES... CO...Red Flag Warning until 9 PM MDT this evening for COZ201-205- 290>293. Heat Advisory until 9 PM MDT this evening for COZ006. UT...Red Flag Warning until 9 PM MDT this evening for UTZ485>487- 491. Heat Advisory until 9 PM MDT this evening for UTZ024-027-029. && $$ UPDATE...MDA SHORT TERM...KAA LONG TERM...NL AVIATION...TGJT FIRE WEATHER...KAA