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573 FXUS65 KBOU 281114 AFDBOU Area Forecast Discussion National Weather Service Denver/Boulder CO 514 AM MDT Sat Jun 28 2025 .KEY MESSAGES... - Hot today with a slight chance of afternoon showers and thunderstorms. - Cooler Sunday and Monday with higher coverage of storms and a threat for some of these storms to be strong to severe. - Early indications are showing a wet Fourth of July. && .DISCUSSION /Through Friday/... Issued at 237 PM MDT Fri Jun 27 2025 Radar shows isolated showers and storms this afternoon mainly from Monument Hill to Brush. Radar is also picking up many small microbursts under these showers and storms. Soundings show a mixed layer up to around 600 mb and the SPC mesoanalysis page shows DCAPE around 1,600 j/kg across the eastern plains. Both of these would indicate storms are capable of producing gusts up to 50 mph with isolated 60 mph wind gusts. Small hail is possible as well although severe hail is not expected. Saturday will be nearly a repeat of Friday. Isolated storms will form in the afternoon and with healthy DCAPE values, gusts up to 50 mph will be possible out of storms. The only changes for tomorrow are that the temperatures will be a degree or two warmer and there may be a slight decrease in coverage of showers and storms due to warmer air aloft. Models have major disagreements about a cold front moving through on Sunday. Some models barely have any sign of a cold front and keep highs around 90 across the plains. Other models show a rather strong cold front with highs in the low to mid 80s across the plains. How strong this front ends up being will determine the location and strength of storms. If the front is stronger, there will be higher upslope wind speeds and dew points close to 60 degrees. This could lead to strong to severe storms that form closer to the I-25 corridor given mixed-layer CAPE around 2,000 j/kg. The limiting factor will be deep layer shear in that scenario as values may only be around 30-35 knots. If the front is weaker, there will be less instability and upslope flow. This would lead to lower coverage of storms and would keep the severe threat closer to the CO/NE border. At this time, the scenario with the stronger front is favored and highs were decreased slightly and PoPs were increased slightly. On Monday, there will be easterly winds throughout the day across the plains that will bring healthy moisture up to the foothills and I-25 corridor. This upslope flow with healthy moisture will lead to good coverage of storms (50-70% coverage) in the foothills and southern I-25 corridor. Some storms could be strong to severe. An upper level ridge will be directly over Colorado on Tuesday and Wednesday. This will lead to warming and drying conditions. With that being said, isolated afternoon showers and storms will be possible mainly over the higher terrain. The aforementioned ridge will move eastward towards Kansas on Thursday and Friday as an upper level trough will move over the Intermountain West. In between these features, the southerly flow will draw up moisture from the Gulf of California. This moisture along with slight upslope forcing ahead of the trough, will lead to scattered to widespread coverage of showers and storms each day. Unfortunately, the Fourth of July could be a wet one this year. && .AVIATION /12Z TAFS through 12Z Sunday/... Issued at 510 AM MDT Sat Jun 28 2025 SSE winds will become more SSW in the next hour or two. By 17z expect a light north or NNE component will may become more NE by 21z. Winds will then transition to SSE by 02z and then SSW by 06z. There is a 10% chance of a high based shower/virga between 21z and 02z which could produce brief gusty winds up to 30 mph if they were to develop. && .BOU WATCHES/WARNINGS/ADVISORIES... None. && $$ DISCUSSION...Danielson AVIATION...RPK