Area Forecast Discussion
Issued by NWS Grand Junction, CO
Issued by NWS Grand Junction, CO
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213 FXUS65 KGJT 101134 AFDGJT Area Forecast Discussion National Weather Service Grand Junction CO 534 AM MDT Mon Jun 10 2024 .KEY MESSAGES... - Showers and storms continue today, favoring the southern mountains and the Divide. Gusty outflow winds will be the primary threat from storms. - Temperatures will cool slightly today, then inch upward by Wednesday, with highs nearly 15 degrees over normal expected Wednesday afternoon. - Drier weather is expected from Tuesday onwards. Active weather returns late week as the next system arrives Friday, along with some temperature relief. && .SHORT TERM /THROUGH TUESDAY/... Issued at 315 AM MDT Mon Jun 10 2024 A weak circulation spinning over the Front Range has fueled isolated showers early this morning and this will continue throughout the day as another round of scattered showers and thunderstorms is expected. These upslope conditions have resulted in an uptick in mid- and upper-level moisture while dry air continues to plague the lower levels of the atmosphere, as evident by the prominent inverted-V on the 00Z GJT sounding. Even so, this does still translate to PWATs that are well above normal with dewpoints projected to reach the mid to upper 30s for much of the region this afternoon. Slightly better forcing from the surface low itself paired with additional moisture advection will result in better thunderstorm coverage today, particularly across the southern Colorado mountains, though instability remains marginal at best. So, similar to yesterday, activity will favor the higher terrain with gusty outflow winds being the primary concern. However, brief periods of moderate to even heavy rain cannot be ruled out. Even though much of the storms will be anchored to the terrain, outflow boundaries from collapsing storms will help fire off storms in the valleys later on in the day. Another area of focus for precipitation today will be our far northern zones where the base of a trough pushing through Wyoming will help fuel isolated to scattered storms. Shower and thunderstorm activity dwindles after sunset as the northern trough and eastern low both exit towards the Plains. This will allow high pressure to build overhead across eastern Utah and western Colorado for Tuesday. While daytime heating will act on residual moisture to fuel orographically-driven convection Tuesday afternoon, dry weather is expected elsewhere. After a slightly cooler day today, temperatures will once again rebound back to several degrees above normal for Tuesday. && .LONG TERM /TUESDAY NIGHT THROUGH SUNDAY/... Issued at 315 AM MDT Mon Jun 10 2024 Strong zonal flow across the northern CONUS will hold the storm track and any chance of cooler air well away from our area to start this period. We will be looking at a hot a dry mid week forecast as the SubTrop High squeezes into the 4 Corners Region...caught between another closed Baja system and a Southern Plains low. Highs both Wednesday and Thursday look to be around 10 to 15 degrees above normal in most areas with triple digits pushing back into the lower desert valleys. Very dry air moving into the area will help the atmosphere heat up but also radiate efficiently at night with some relief as lows drop into the 60s. Moisture will begin to move back into the region Thursday night as the upstream low begins to kick eastward into the Desert Southwest. PWAT anomaly is 1-2 StdDev by Friday as the upper low moves into the Great Basin. There is still a bit of discrepancy between global models on whether the main circulation of this low stays to our South...or lifts across if in the GFS camp. Either way the trough will provide some large ascent for storm formation in the afternoon and a cooler wetter forecast is in the cards for now. However this push of moisture is brief and the storm progressive so feel the lower levels won`t have a lot of time to saturate. This means a high based storm mode with gusty outflow winds would be the main threat...though under the right outflow boundary conditions a few stronger organized storms might be able to produce some heavier rainfall rates. In the GFS solution another decent lee side fropa event will provide upslope moisture convergence along the divide and it blows up storms there by late afternoon with the northern trough solution. Confidence will need to increase before messaging any threats. Dry weather returns for the weekend as another anomalous weather pattern sets up across NW NOAM with a digging trough dipping across the PacNW into the Intermountain West. Warm and breezy Southwest flow will be the end result for our CWA in this pattern. && .AVIATION /12Z TAFS THROUGH 12Z TUESDAY/... Issued at 534 AM MDT Mon Jun 10 2024 Moisture wrapping westward into southern portions of Colorado and Utah will bring a chance of light showers this morning but VFR should continue to prevail. This moisture blossoms into thunderstorms again by early afternoon with the biggest threat over southwest Colorado and into the central mountains. Brief moderate showers are possible along with gusty outflow winds. KDRO...KGUC and KTEX have the highest probability of these storms moving over the airfield but confidence still not high enough to go beyond VCTS attm. && .HYDROLOGY... Issued at 337 AM MDT Sun Jun 9 3374 Hydrographs continue to trend downward today as the snowpack has largely dwindled and temperatures cool compared to this weekend. As a result, all ongoing advisories are still on track to be discontinued later on this afternoon and evening. Even so, please continue to use caution when walking near riverbanks. && .GJT WATCHES/WARNINGS/ADVISORIES... CO...None. UT...None. && $$ SHORT TERM...MMS LONG TERM...15 AVIATION...TGJT HYDROLOGY...TGJT