Area Forecast Discussion
Issued by NWS Grand Junction, CO
Issued by NWS Grand Junction, CO
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249 FXUS65 KGJT 231738 AFDGJT Area Forecast Discussion National Weather Service Grand Junction CO 1138 AM MDT Mon Sep 23 2024 .KEY MESSAGES... - A weak disturbance in northwest flow combined with modest levels of moisture lingering from this weekend`s storm is expected to generated isolated storms over the higher terrain this afternoon with the southern San Juan Mountains favored. - Dry and warm conditions are expected during the remainder of the week as high pressure settles over the region. Near record highs are expected from Thursday through the weekend. && .SHORT TERM /THROUGH TUESDAY/... Issued at 328 AM MDT Mon Sep 23 2024 Aside from far southwest Colorado, skies were clear over much of the region early this morning. Clouds hanging on over the south appeared to be due to the trailing, positive tilt mid- level trough stretching west-southwestward from the central Plains according to latest RAP13 analysis. Daytime warming will generate scattered cumulus over the higher terrain beginning late this morning. During the afternoon a low amplitude mid- level short wave trough will sweep southeastward over the area which should generate some isolated showers/thunderstorms over the higher terrain despite limited moisture. NAM and GFS both suggested moisture over the southern San Juan Mountains a bit deeper as in previous runs, so kept better chances north and east of Pagosa Springs. Meanwhile, increased sunshine and warm air advection should cause temperatures to recover to near normal or just a bit above this afternoon. Expect skies to clear this evening as a ridge of high pressure builds over Great Basin and Intermountain north. This will allow for strong radiational cooling and morning lows close to normal. The ridge is driven eastward on Tuesday as a long wave trough moves toward the West Coast. A subsidence inversion becomes apparent in forecast soundings near 600 mb as the high takes hold. Consequently, look for dry and warm conditions with plenty of sunshine on Tuesday. Afternoon highs warm by a degree or two putting readings right around 5 degrees above seasonal norms. && .LONG TERM /TUESDAY NIGHT THROUGH SUNDAY/... Issued at 328 AM MDT Mon Sep 23 2024 A classic omega block, albeit short lived, will be centered over the CWA at the start of the long term period. High pressure directly overhead will bring sunny skies, light winds, and once the center of high pressure starts shifting eastward, warming temperatures. An approaching trough coming ashore across the PacNW on Wednesday will be the push needed to force the ridge axis and high pressure center further east. This will cause winds to become southwesterly allowing warm air advection to kick in. High temperatures here on out will run about 10, to maybe near 15, degrees above seasonal values. In fact, forecast highs from Thursday through Sunday will be near record levels. Dry and clear skies will continue to be the rule as disturbances are expected to ride up and over the ridge keeping any inclement weather well to our north. The remainder of the long term, as per deterministic models, will rebuild high pressure over the desert southwest as much more active weather materializes along the Gulf Coast and central states. We`ll keep those dry and warm conditions in place with generally light winds also remaining in place. && .AVIATION /18Z TAFS THROUGH 18Z TUESDAY/... Issued at 1136 AM MDT Mon Sep 23 2024 A few building clouds over the terrain are occurring late this morning...a few of which may lead to some light showers over the southern mountains through sunset. However VFR conditions will prevail under a light wind regime. The biggest challenge will be forecasting the return of low clouds/ground fog near KGUC again tonight...confidence low but placed a hint in the forecast for now. && .GJT WATCHES/WARNINGS/ADVISORIES... CO...None. UT...None. && $$ SHORT TERM...NL LONG TERM...TGR AVIATION...TGJT