Area Forecast Discussion
Issued by NWS Grand Junction, CO

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377 FXUS65 KGJT 182311 AFDGJT Area Forecast Discussion National Weather Service Grand Junction CO 511 PM MDT Sun Apr 18 2021 .SHORT TERM...(Tonight through Monday night) Issued at 232 PM MDT Sun Apr 18 2021 A pleasant day will turn into a tranquil night with cool overnight lows expected. A few showers are possible near Wolf Creek Pass but all in all, dry conditions are expected through tomorrow afternoon. Tonight, clouds will be on the increase from north to south ahead of a cold front that`s currently in Montana. By Monday morning, the front will be over central Wyoming and as it gets closer, the pressure gradient will start to tighten causing an uptick in wind speeds. Debated on adding to the current wind advisories for the I-70 corridor up to Eagle and also the Montrose area but some discrepancies popped up. The EC ensembles are very bullish in stronger winds for those areas while statistical guidance...not so much. Forecast Skew-Ts do show some midlevel clouds moving in and possibly cutting off any deeper mixing...and thus weaker surface winds. A few more runs will help so held off on expanding the wind advisory for now. The current Red Flag Warnings remain in effect as described below. As far as the front is concerned, it will move into the CWA between noon and 3PM and will bring valley showers (northern valleys), some mountain snows (2 to 4 inches for Park Range), and a few rumbles of thunder as it continues to push southward. Heavier precip will shift to the central mountains around 9PM and by midnight, most precip will be over aside from some precip over the San Juans. .LONG TERM...(Tuesday through Sunday) Issued at 232 PM MDT Sun Apr 18 2021 Dry northwest flow will prevail Tuesday in the wake of the departing cold front with daytime highs sitting 10 to 15 degrees below normal across the north and by 5 to 10 degrees further south. Tuesday will also see the next Pacific wave trek along the west coast before dropping into the Great Basin Tuesday night. This system will slowly shift east throughout the day on Wednesday resulting in a shift to westerly flow aloft over eastern Utah and western Colorado. Even with the increase in clouds ahead of the trough temperatures will warm by several degrees. Embedded moisture in the flow may also initiate some orographic showers along the Continental Divide Wednesday morning and early afternoon. Activity will increase into the evening hours as the open wave lifts across the region before sliding east of the Divide on Thursday. A secondary weak wave will move through on Thursday night before the base of a final trough extending south from Canada also passes overhead late Friday. This unsettled pattern will lead to periods of showers from mid to late week with the best coverage of showers centered along the Divide. As has been the case with the last several systems, any snow that falls will be confined to the highest elevations with the majority of precipitation falling during the daytime hours. As a result, impacts will be limited given the high April sun angle. A ridge of high pressure will build overhead during the weekend keeping conditions quiet and dry. The new work week could be interesting as a strong low pressure system intensifies off the west coast. && .AVIATION...(For the 00Z TAFS through 00Z Monday evening) Issued at 508 PM MDT Sun Apr 18 2021 VFR conditions are expected tonight and tomorrow morning. A cold front will drop southward through the northern sites tomorrow afternoon. Showers may be possible along the front mainly across northwest Colorado. Strong winds are expected at most sites tomorrow afternoon. && .FIRE WEATHER... Issued at 232 PM MDT Sun Apr 18 2021 A strong cold front will move through Monday afternoon, favoring showers over the northern and central mountains. Valleys will remain dry with virga showers up north and windy conditions with gusts to 40 mph or higher. This will result in critical fire weather conditions for lower elevations of east- central to southeast Utah and west-central to southwest Colorado tomorrow. Strong winds and dry conditions across the Four Corners area may persist well into next week. && .GJT WATCHES/WARNINGS/ADVISORIES... CO...Red Flag Warning from noon to 9 PM MDT Monday for COZ203-207-290- 292-295. Wind Advisory from noon to 9 PM MDT Monday for COZ001-002-006. UT...Red Flag Warning from noon to 9 PM MDT Monday for UTZ490-491. Wind Advisory from noon to 9 PM MDT Monday for UTZ024-027. && $$ SHORT TERM...TGR LONG TERM...MMS AVIATION...TGJT FIRE WEATHER...TGJT

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