


Area Forecast Discussion
Issued by NWS Denver/Boulder, CO
Issued by NWS Denver/Boulder, CO
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896 FXUS65 KBOU 150057 AFDBOU Area Forecast Discussion National Weather Service Denver/Boulder CO 657 PM MDT Wed May 14 2025 .KEY MESSAGES... - Showers and thunderstorms with strong winds moving across northeastern Colorado through early evening. Main threat is marginally severe wind gusts. - Potential for strong winds in the foothills late tonight through mid morning on Thursday. Gusts in the 60-70 mph range possible in wind prone areas. - Windy again with increased shower and thunderstorm activity expected again starting Sunday. && .UPDATE... Issued at 513 PM MDT Wed May 14 2025 Updated for higher coverage of rain and slightly higher wind gusts. Severe gusts aren`t widespread, but there are quite a few 50-60 mph gusts associated with the storms, and some higher. There hasn`t been much large hail, but the stronger updrafts are supporting hail near 1 inch in diameter. && .DISCUSSION /Through Wednesday/... Issued at 308 PM MDT Wed May 14 2025 The expected shower/thunderstorm area has developed nicely, and is extending south a bit more than expected. This activity will shift eastward through early evening. The main threat will be strong winds, and the current organization would suggest an enhanced threat of an organized wind field developing along this line. Some convection allowing models today have been really ambitious with 70-80 mph gusts, but there`s a high bias with these, at least in the coverage. The idea of widespread 30-40 mph winds with some places getting gusts up to 65 mph still looks good, perhaps the probability of severe gusts is looking a little higher than it did earlier today. Behind the current shortwave the flow aloft goes more westerly quickly. There`s a window of opportunity for a mountain wave later tonight into Thursday morning with about 40 knots of cross barrier flow, though the wind and temperature profiles aren`t favorable for much amplification. We think the high wind threat is small, but we do expect another round of 40-60 mph gusts in wind prone areas early Thursday. There will still be some wind on Thursday, especially across the north, but less than this afternoon. Friday and Saturday look relatively quiet. There will still be a little wind, and a low level of diurnal shower/thunderstorm activity. Lower humidities across the southern part of our area may be near critical thresholds, but fuels are currently green so the threat is greatly reduced. There are a couple wrinkles in the forecast from Sunday onward. Last night`s operational EC kept the large low that develops over the southwest intact and brought it across Colorado in one piece on Monday. This is against a trend in most model runs for a significant shortwave to lift out of the mean trough across Colorado on Sunday, and the trend in those models is also further north with that. This could bring a warm, dry, windy day Sunday instead of a thunderstorm day if that trend continues. But if it`s a little further south, we could still have a frontal passage with a transition from warm to stormy. The NBM seems to track with most of the models on the temperature and wind fields, but the higher PoPs on Monday are a bit of a mystery. We`re not sure if it`s due to those EC solutions from last night, or if it`s that some of the models are producing "day 2" storms on Monday behind the lead trough. It doesn`t seem like there`s that much precipitation in the model suite that we`ve seen. There`s probably a better chance on Tuesday as we have more chance for a plains airmass to settle in and destabilize, and there may be another piece of the trough or the main trough itself moving east to the south of us. NBM trend of drier Tuesday is suspect, we`ll see how model trends continue overnight. && .AVIATION /00Z TAFS through 00Z Friday/... Issued at 648 PM MDT Wed May 14 2025 VFR is expected for the TAF period. Northerly winds will relax this evening and will turn toward drainage around midnight. WNW winds will likely develop tomorrow but may not be as persistent as the TAFs would indicate. There will likely be some periods where winds at DEN and APA will be light and variable in-between the moderate westerly winds. In addition, there may be weak showers in the afternoon that could create sporadic wind gusts. Winds will then go back toward drainage Thursday night. && .BOU WATCHES/WARNINGS/ADVISORIES... None. && $$ UPDATE...Gimmestad DISCUSSION...Gimmestad AVIATION...Danielson