Area Forecast Discussion
Issued by NWS Denver/Boulder, CO
Issued by NWS Denver/Boulder, CO
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139 FXUS65 KBOU 251543 AFDBOU Area Forecast Discussion National Weather Service Denver/Boulder CO 943 AM MDT Wed Sep 25 2024 .KEY MESSAGES... - Warm and dry for the foreseeable future with very limited chances of precipitation. The mountains have a 10-20% chance of showers late Friday into Saturday. - Record highs possible on Thursday and Sunday. && .UPDATE... Issued at 930 AM MDT Wed Sep 25 2024 GOES satellite imagery paints a pretty clear picture of where the upper-level ridge currently resides this morning. With cloud-free skies stretching from the Mississippi River west to California, it will be another quiet weather day here in northern Colorado. The current forecast needs no adjustments on this update. && .SHORT TERM /Through Tonight/... Issued at 133 AM MDT Wed Sep 25 2024 An upper level ridge axis is centered near the UT/CO border this morning, and will continue to drift eastward today... ending up over eastern Colorado by the evening. Depending on your ensemble and model climate of choice, 500mb height standardized anomalies are around 1-2 sigma (~90-95th percentile). Unsurprisingly, it`s going to be warm underneath this ridge, especially as mid-level temperatures warm and skies remain clear. Forecast highs are in the mid to upper 80s today and look to be warmer tomorrow. Overnight lows will also remain above average with lows in the upper 40s to mid 50s. && .LONG TERM /Thursday through Tuesday/... Issued at 133 AM MDT Wed Sep 25 2024 An anomalously strong ridge which will be over Colorado today will slide slightly southward on Thursday. A weak trough will pass well to the north of Colorado but this feature will lower 500 mb heights and temperatures. In the low levels, 700 mb will warm to around 16-17 C and with light downslope flow, highs will reach near record highs. The forecast still calls for Denver to reach 90 which would tie the daily record. On Friday, the ridge will build back northward and there will be very little, if any, wind at 500 mb over Colorado. At the surface, a weak front will push through in the morning shifting winds to the northeast across the plains and foothills. This will cool temperatures down a few degrees but highs will still be well above normal. With the convergent flow over the mountains, there may be just enough forcing and instability to generate a couple showers and perhaps a weak thunderstorm. No impacts are expected from these. The ridge aloft will only strengthen this weekend as subsident flow will persist over the Intermountain West while there is a strong trough and remnants of a hurricane over the southeast US. Warm and dry conditions will persist. Ensemble data is starting to converge on a solution that has Sunday reaching near record high temperatures. The high temperature forecast for Denver was increased to 89 F which is a few degrees below the daily record of 92 F. There is plenty of uncertainty by Monday and into Tuesday. Some ensemble runs keep the strong ridge in place while a weak trough passes too far to the north to have an impact on our weather. In that case, Monday and Tuesday may continue to have highs in the upper 80s across the plains. However, some ensemble runs are more aggressive with a trough that brings a cold front through. In these solutions, highs may only be in the mid 70 across the plains. These patterns tend to take longer than expected to progress so the warmer temperatures are favored. Into the middle of next week, warm and dry conditions are expected as the ridge aloft does not want to move or weaken. && .AVIATION /12Z TAFS through 12Z Thursday/... Issued at 531 AM MDT Wed Sep 25 2024 VFR through the TAF period. Drainage flow will slowly turn to more of a southeast or east wind from late morning into the early afternoon, before transitioning back to drainage this evening. No cloud cover is expected through tonight. There may be a brief period of stronger drainage flow around 03z tomorrow but otherwise wind speeds should remain near or below 10kt. && .BOU WATCHES/WARNINGS/ADVISORIES... None. && $$ UPDATE...Bonner SHORT TERM...Hiris LONG TERM...Danielson AVIATION...Hiris