Area Forecast Discussion
Issued by NWS Denver/Boulder, CO
Issued by NWS Denver/Boulder, CO
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148 FXUS65 KBOU 191825 AFDBOU Area Forecast Discussion National Weather Service Denver/Boulder CO 1225 PM MDT Wed Jun 19 2024 .KEY MESSAGES... - Continued cool today with scattered showers and a few storms. - Scattered thunderstorms Thursday and Friday. - Hotter and drier this weekend into early next week. && .UPDATE... Issued at 1010 AM MDT Wed Jun 19 2024 GOES-16 satellite imagery shows a mixture of clouds across the forecast area this morning. With persistent cloud coverage expected throughout the day, max temperatures were lowered a few degrees, especially along the Palmer Divide and adjacent plains to account for the lack of surface heating. The rest of the current forecast looks to be intact, so will leave as is. && .SHORT TERM /Through tonight/... Issued at 308 AM MDT Wed Jun 19 2024 Persistent SW flow aloft will remain over the area today thru tonight. At the sfc, high pres will slowly move eastward allowing for the low level flow to become more southeast by aftn, across the plains. As a result, should see deeper low level moisture to the east and southeast advect into the area. Overall, can`t find any defined disturbance embedded in the SW flow aloft to help enhance convection this aftn. So it appears will have to rely on convective temps being reached. Most of the plains will have low level cloud cover in place thru the aftn so this would prevent convective development. Portions of the higher terrain should reach convective temps this aftn with sct showers and tstms developing. Outflow boundaries from this activity could trigger some activity along portions of the I-25 Corridor by late aftn. Overall, CAPE at lower elevations will be fairly minimal unless temps rise into upper 75 to 80 degree range. At this time, have kept the highest pops over the higher terrain with lower chances elsewhere. Highs this aftn, will be mainly in the 60`s across the plains. However, some areas may not rise above 60 degrees where low level cloud cover is expected to persist thru the aftn. Meanwhile, around the Denver area readings may rise into the lower 70s if cloud cover breaks up. For tonight, will continue to see an increase in low level moisture across the plains. Should see a warm air advection pattern develop overnight. This could lead to a chc of nocturnal storms overnight over portions of the plains, however, confidence isn`t high as to overall coverage. Thus have kept pops mainly in the chc category due to uncertainty. && .LONG TERM /Thursday through Tuesday/... Issued at 402 AM MDT Wed Jun 19 2024 A strong ridge of high pressure over the eastern United states is expected to push westward Thursday and Friday. This will bring a return to summer heat for the forecast area. Models keep southwesterly flow aloft over the forecast area Thursday through Friday night. The QG Omega fields also continue to indicate weak upward synoptic scale energy for the CWA through the period with perhaps slightly stronger energy Friday night as a weakening upper level trough moves across. In the lower levels models show a pretty weak pressure gradient across the state with weak low pressure east of the mountains. Southerly low level winds will dominate over the plains on Thursday with a weak cold behind and northeasterly winds on Friday. Moisture will increase on Thursday with precipitable water values climbing into the 0.80 to 1.40 inch range by late in the day. With temperatures expected to be about 20 degrees warmer than today`s readings, there is fairly decent CAPE progged. Expect better instability on Thursday compared to today. Will go with 20-50% pops for most of the CWA with a few strong storms possible. Moisture looks just as prevalent on Friday and Friday night with precipitable water values as high as 1.50 inches over the plains. Temperatures by be a bit cooler than Thursday`s with some models showing a weak cold front to move into the plains. The CAPE looks pretty good. Will go with 20-70% pops in the afternoon and evening with highest values in the mountains and foothills. Models also keep some precipitation going overnight in the alpine areas. Storms may not be as strong than the Thursday storms. For temperatures, Thursday`s highs are expected to be 6-11 C warmer than today`s highs. Friday`s reading look to be a tad cooler than Thursday`s highs. For the later days, Saturday through Tuesday, the models continue to move the upper ridge westward into the southwestern/south central United States by Sunday. This upper ridge looks to stay there much of next week. Hot temperatures will be the main weather story those four days, especially over the plains where mid and upper 90s are expected. The chance of rain and thunderstorms will be minimal over the plains all four days, with slightly higher chances over the alpine areas. && .AVIATION /18Z TAFS through 18Z Thursday/... Issued at 1149 AM MDT Wed Jun 19 2024 Ceilings continue to fluctuate this morning at and around the 5000-8000 ft range. This is expected to continue with a pronounced lifting not anticipated until later tonight. The persistent cloud coverage has kept temperatures cool across the area and winds have become increasingly gusty a little ahead of schedule, which are expected to keep a gusty and southerly component through the evening at DEN/APA. The latest guidance shows potential for winds to gust in the low 30kt range at DEN/APA. There is low probability that a thunderstorm passes near APA this afternoon, however, with the persistent cloud coverage and low instability, showers are the most likely scenario, so have left out of the TAF. With greater instability over the higher terrain this afternoon, have put VCTS at BJC as a storm may develop over the high country and move east across the area. There is still a chance this doesn`t happen with the current cloud cover. Winds at BJC look to become variable around 4Z tonight and guidance shows this continuing through the morning. There is a chance a Denver Cyclone develops and N/NE winds setup. Or southerly winds may be another option. Either way, winds are expected to stay light for either scenario. && .HYDROLOGY... Issued at 404 AM MDT Wed Jun 19 2024 There will be minimal threat of flash flooding in the burn scars this aftn especially over Cameron Peak and Williams Fork. A limited flash flood threat will continue Thursday and Friday. && .BOU WATCHES/WARNINGS/ADVISORIES... None. && $$ UPDATE...Bonner SHORT TERM...RPK LONG TERM....RJK AVIATION...Bonner HYDROLOGY....RPK/RJK