Area Forecast Discussion
Issued by NWS Denver/Boulder, CO
Issued by NWS Denver/Boulder, CO
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533 FXUS65 KBOU 052104 AFDBOU Area Forecast Discussion National Weather Service Denver/Boulder CO 304 PM MDT Wed Jun 5 2024 .KEY MESSAGES... - Summer heat through the rest of this week, with Friday the hottest day. - Increasing chances for showers and thunderstorms this weekend into early next week, along with slightly cooler temperatures. - Gradual trend towards warmer/drier weather towards the middle of next week. && .SHORT TERM /Through Thursday/... Issued at 246 PM MDT Wed Jun 5 2024 There are a few weak convective clouds around the CWA early this afternoon but no precipitation. Cloud coverage over the CWA is about 1% at present. Most of the CWA has southwesterly to northwesterly winds currently. Gusts up to 35 mph have been recorded this afternoon. It did hit 90 F at DIA a few minutes ago for Denver`s first 90 degree reading of 2024. Models show the upper ridge to push eastward into the CWA by Thursday. The flow aloft will be west and northwesterly overnight and Thursday. The QG Omega fields have benign synoptic scale motion for the CWA the first two periods. A cold front is still expected to push southward across the plains late this evening with weak upslope flow behind it for a few hours. Southeasterly low level winds are progged for the plains and lower foothills on Thursday. For moisture, the precipitable water values are progged in the 0.50 to 0.90 range for the CWA tonight and Thursday. There is some CAPE around on Thursday, mainly over the foothills and southern CWA. The QPF fields are dry, with a tad of measurable rainfall over the far southwest/south central CWA late day Thursday. Will keep the minor late day pops going for south central CWA. For temperatures, Thursday`s highs will be a tad cooler than today`s highs. && .LONG TERM /Thursday night through Wednesday/... Issued at 246 PM MDT Wed Jun 5 2024 Main story of the long term forecast is a period of increased moisture and increased precipitation chances across most of the forecast area. Mid-level moisture is expected to increase on Friday on the edge of a thermal ridge axis centered over Colorado. 700mb temperatures are quite warm and deterministic models would support low/mid-90s across the plains, though the increasing moisture and a subtle shortwave on the periphery of the upper ridge would support cloud cover that may limit temperatures. The increasing moisture aloft will also support some widely scattered showers and thunderstorms by the afternoon hours with modest instability. The better low-level moisture arrives this weekend, and will lead to increased precipitation chances. Ensemble guidance continues to support a broad moist airmass across the region (PWATs >150% of normal) with roughly 500-1000 J/kg of CAPE each afternoon. Main question is if we get any strong forcing mechanism for organized convection or if things stay a bit less organized and dependent on more subtle boundary collisions to drive storms in the afternoon. Guidance does pick up on a few weak shortwaves embedded in the flow but disagree on the timing of most of these features. At some point, a weak cold front may also push into the region either late this weekend or sometime Monday. Moisture may linger into early next week, but guidance largely agrees on a broad ridge axis building back across the Four Corners region as we get towards mid-week. Timing and strength of the upper ridge is up in the air (pun somewhat intended), but a warming/drying trend is likely by the end of the forecast period. && .AVIATION /18Z TAFS through 18Z Thursday/... Issued at 1120 AM MDT Wed Jun 5 2024 Models have west, then northwesterly winds at DIA through about 06z, then a cold front with northeasterly winds moves in. Most of the models never show drainage winds at DIA overnight. Southeasterlies are indicated by late Thursday morning. There will be no ceiling issues. && .HYDROLOGY... Issued at 246 PM MDT Wed Jun 5 2024 Snow melt is continuing across the higher elevations, with elevated flows across a few creeks/rivers over the high country. Main area of concern is across the upper Colorado River basin. In addition, there is a limited threat of burn area flash flooding this weekend into early next week, as an anomalously moist airmass advects into the region. Scattered showers and thunderstorms are forecast most afternoon, which would be capable of brief heavy downpours. However, mean cloud-layer flow should be strong enough (15-25kt) to keep the overall chances of heavy rain/flash flooding low. && .BOU WATCHES/WARNINGS/ADVISORIES... None. && $$ SHORT TERM...RJK LONG TERM...Hiris AVIATION.....RJK HYDROLOGY...Hiris