Area Forecast Discussion
Issued by NWS Denver/Boulder, CO
Issued by NWS Denver/Boulder, CO
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529 FXUS65 KBOU 250300 AFDBOU Area Forecast Discussion National Weather Service Denver/Boulder CO 900 PM MDT Mon Jun 24 2024 .KEY MESSAGES... - Continued Hot Tuesday with Heat Advisory for the Denver Metro. - High based showers and thunderstorms this afternoon into the early evening with gusty winds. - Slight cool down and increased chances for thunderstorms Wednesday and Thursday. - Some storms on Wednesday could be strong with heavy rain and severe weather, especially across the plains east of Denver. && .UPDATE... Issued at 851 PM MDT Mon Jun 24 2024 Although low temperatures will hover near the mid to upper 60s tonight for Boulder, Jefferson, and Broomfield counties, the Heat Advisory was allowed to expire. An additional Heat Advisory continues for Denver until 9 PM MDT Tuesday. Outflows from decaying showers should end within the next hour or two. Adjustments to wind direction and slightly higher speeds were include in this update until midnight. && .SHORT TERM /Through Tuesday/... Issued at 125 PM MDT Mon Jun 24 2024 Mid level moisture in weak westerly flow aloft is moving across the area this aftn. MLCAPE is around 500 j/kg which is allowing for sct showers/storms over the higher terrain with activity over the plains more widely sct. DCAPE values are around 1500 j/kg so a few of the storms may still produce wind gusts to 50-55 mph. This activity will linger into the early evening hours before ending around 03Z or so. On Tue, it appears there will be a decrease in overall moisture along with not as much instability. Thus expect any high based shower/tstm activity will be more isold and confined to mainly the higher terrain. Highs will remain well above normal with readings in the 95 to 100 degree range across much of the plains. Will keep the heat advisory in place for the Denver metro on Tue as well. && .LONG TERM /Tuesday night through Monday/... Issued at 125 PM MDT Mon Jun 24 2024 Upper level high pressure will remain centered over the Central and Southern Rockies Tuesday night and Wednesday with above normal temperatures continuing. Models are showing a weak cool front moving across Northeastern Colorado Tuesday evening with increased low level moisture behind it. There should also be an increase in subtropical moisture moving into Colorado from the Desert Southwest. As a result, slightly cooler temperatures are expected across the forecast area along with a better chance for precipitation region wide. With PW`s on the plains ranging from 1.00" to over 1.50" there is the potential for heavy rain, especially east of the Front Range Urban Corridor. In addition, some of the models are suggesting the potential for a few strong to severe storms mainly east and northeast of Denver during the afternoon and evening hours due to quite a bit of instability and plenty of shear. With the additional cloudiness and precipitation around, temperatures should be somewhat lower than previous days, but still hot with highs in the upper 80s to mid 90s on the plains. On Thursday, the upper ridge flattens in response to an upper level shortwave moving across the Northern Rockies. Moisture levels and shear should be somewhat less. Consequently, there may be a lower threat for severe storms and heavy rain than on Wednesday. One thing to note is that the GFS deterministic and ensemble runs as well as the GEM solution is showing quite a bit of precipitation across portions of the high country Thursday evening. Nothing really stands out when looking at the models other than a southwest to northeast 50kt upper jet moving over Western and Central Colorado which could be the reason for the enhanced precipitation. Due to the model differences, there is quite a bit of uncertainty if the heavier precipitation will occur. Friday looks to be somewhat drier and cooler across the CWA as we see some cool air advection at mid levels and downsloping flow east of the mountains. Saturday looks to be the coolest day of the week as another cold front moves across the region. Max temperatures on the plains are only expected to climb into the upper 70s and lower 80s. Precipitation chances may be limited across far Northeastern Colorado due to the presence of a cap with better chances across the high country, adjacent plains and Palmer Divide. There should still be enough available moisture and instability to produce a few stronger storms with brief heavy rain and small hail, mainly over the higher terrain. On Sunday, the models show the upper high centered over Arkansas with an upper trough over the western U.S. This is more of a classic monsoon setup and if it verifies, we could see more numerous showers and storms across the forecast area with the potential for heavy rain in some areas. There is also the potential for some severe weather across the plains as surface winds turn southeasterly and richer low level moisture advects into the area. By Monday, precipitation chances may decrease as the monsoonal plume of moisture gets shunted south and eastward in response to the upper trough pushing into Colorado from the west. && .AVIATION /00Z TAFS through 00Z Tuesday/... Issued at 554 PM MDT Mon Jun 24 2024 VFR conditions are expected through the TAF period. Scattered showers will continue until 03Z this evening producing wind gusts up to 25kts. Drainage winds will occur near 04Z for all terminals. Tuesday, isolated showers may lead to northerly winds producing gusts between 20-24kts in the afternoon. && .HYDROLOGY... Issued at 125 PM MDT Mon Jun 24 2024 Increased moisture will lead to a potential for moderate to heavy rain across the forecast area Wednesday and Thursday. The plains east of the Front Range Urban Corridor will see the greatest threat late Wednesday afternoon and evening. We may see another threat for heavy rain across portions of the forecast area on Sunday as monsoonal moisture moves over the area. && .BOU WATCHES/WARNINGS/ADVISORIES... Heat Advisory until 9 PM MDT Tuesday for COZ040. && $$ UPDATE...AD SHORT TERM...RPK LONG TERM...JK AVIATION...AD HYDROLOGY...JK