Area Forecast Discussion
Issued by NWS Grand Junction, CO
Issued by NWS Grand Junction, CO
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785 FXUS65 KGJT 171118 AFDGJT Area Forecast Discussion National Weather Service Grand Junction CO 518 AM MDT Fri May 17 2024 .KEY MESSAGES... - Warm and breezy conditions are expected through the weekend. Temperatures will remain at least 5 to 10 degrees above normal. - A series of systems will bring daily showers and thunderstorms Saturday and Sunday afternoon. Gusty outflows and small hail will be the main concerns. - Cooler, unsettled weather will prevail early next week before drier and warmer conditions return by midweek. && .SHORT TERM /THROUGH SATURDAY/... Issued at 308 AM MDT Fri May 17 2024 A downturn in excitement is expected today as the forecast area remains under a weak, just barely noticeable, ridge of high pressure. This will lead to quiet weather under mostly sunny skies, though mid and high clouds will begin to increase later on this afternoon. Upstream, a trough of low pressure will begin to dig into the Intermountain West before pushing farther south into the Northern Rockies by this evening. Flow aloft will quickly be deflected to the west as a weak frontal boundary straddles the Wyoming border, resulting in a gradual tightening of the gradient during the day. Surface gusts of 25 to 35 mph are still expected for areas north of I-70 this afternoon with the southern tier generally maxing out at 30 mph. Even with the passing clouds, humidities will hover in the low to mid teens this afternoon. The front will begin to nudge into northeast Utah and northwest Colorado tonight but, with a prevalent dry layer at the surface, little to no shower activity is expected. In fact, PWATs are anticipated to remain 70 to 90 percent of normal into Saturday morning. On Saturday a shortwave will slowly begin to push into southern California, helping to deflect the Friday night cold front out of the area. Flow across the southern two-thirds of the CWA will shift to the southwest in response to the approaching trough on Saturday. PWATs will exceed 150 percent of normal in this moist pattern which, when paired with daytime heating and orographics, will fuel isolated to scattered showers and storms throughout the day. Though the higher terrain will be favored, some drift into the adjacent valleys is expected. As noted previously, additional support from the associated warm front will aid in storm development. Similar to previous days, gusty outflow winds and even some small hail will be the primary threats with convection. Temperatures will remain unseasonably warm through the short term period with today`s highs reaching 6 to 12 degrees above the norm for mid May. The increase in clouds and storms on Saturday will dampen highs a bit but values will remain 5 to 10 degrees above normal. Tonight`s lows will also be quite warm for this time of year. With all of these warm temperatures, those rivers will be rising. No areas of concern at the moment but certainly something to keep in mind when recreating this weekend. && .LONG TERM /SATURDAY NIGHT THROUGH THURSDAY/... Issued at 308 AM MDT Fri May 17 2024 The split flow pattern over the West breaks down Saturday night into Sunday and once again the high latitudes drop across the US border and spreads below normal heights into the mid latitudes. The main trough looks to hang back to our West until the Tuesday timeframe but even now the timing on this is off by half a day between the global models. Either way Tuesday into the mid-week period looks to be the coolest and wettest of the forecast with highs dropping back to and below normal for a few days. Models are still struggling with additional high latitude energy dropping into the general trough over the NW CONUS through the end of the week. The latest GFS is swinging a stronger piece of energy across the Northern Rockies as early as Thursday while the EURO holds it back off the PacNW Coast where it lingers into the weekend. Looking at trends and ensemble clusters the former solution has been more consistent as the latest EURO choice for the deterministic run is drastically different than 12 hours ago. That said looks like Thursday has good probability of being warmer and drier before another cool down arrives late in the week as the system to the North throws a cold front through our area. Moisture anomalies at this point are not significant and this is reflected in only moderate PoPs and a light QPF outcome late in the week. && .AVIATION /06Z TAFS THROUGH 06Z SATURDAY/... Issued at 517 AM MDT Fri May 17 2024 VFR conditions under mainly clear skies can be expected the next 24 hours...with a few afternoon gusts over 25 mph possible. && .GJT WATCHES/WARNINGS/ADVISORIES... CO...None. UT...None. && $$ SHORT TERM...MMS LONG TERM...15 AVIATION...TGJT