Area Forecast Discussion
Issued by NWS Denver/Boulder, CO
Issued by NWS Denver/Boulder, CO
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094 FXUS65 KBOU 122011 AFDBOU Area Forecast Discussion National Weather Service Denver/Boulder CO 211 PM MDT Fri Jul 12 2024 .KEY MESSAGES... - Heat wave through Sunday with temperatures reaching 100 to 105 degrees across the urban corridor and plains. Important to take steps to limit outdoor activity, find ways to cool off, and stay hydrated as much as possible. - A Heat Advisory is in effect today through 8 pm for the I-25 corridor, expanding across all the plains for Saturday and Sunday. - Slight heat relief possible by Monday, but more so by Tuesday and Wednesday. Increasing chance of showers and thunderstorms for that period. && .SHORT TERM /Through Saturday/... Issued at 205 PM MDT Fri Jul 12 2024 Limited cumulus development on satellite this aftn. There is still some potential for isold high based activity mainly along and south of I-70 over the higher terrain and across srn portions of Lincoln county. Radar also show a weak convergence boundary extending from Lincoln county into ern Washington county and Logan county. No cumulus along this boundary but not impossible an isold storm or two could develop along it, late this aftn or early this evening, where sfc based cape is maximized over Logan, Phillips and Sedgwick counties. Overnight through Sat, the center of a large upper level high will remain near the Four Corners area. Little change in 850-700 mb temps expected on Sat with highs staying in the 100-105 range across the plains. Record high at Denver is 100 on Sat, which should be broken. Meanwhile, there will be some increase in mid level moisture on Sat as water vapor imagery does show moisture over Utah rotating around the upper level high this aftn. As a result, will see at least widely sct high based shower/storms over the higher terrain Sat aftn. At lower elevations, with high T-TD spreads, could see isold high based showers, with mainly virga, producing gusty outflow winds across the I-25 Corridor as DCAPE values are decent. Over the far nern plains, sfc based CAPE is fcst to be from 500-1000 j/kg. Thus could see an isold strong storm or two if the cap can be broken by late aftn. && .LONG TERM /Saturday night through Friday/... Issued at 205 PM MDT Fri Jul 12 2024 Record to near record heat is expected to continue on Sunday as upper level high pressure dominates the Southern and Central Rockies. Max temperatures across the plains are expected to range between 100 and 105 degrees with 103 forecasted at DIA which would set a new record for the date. The high county will be quite warm as well with temperatures climbing above 80 in places such as Breckenridge, Dillon and Grand Lake. There should be enough mid level moisture around to produce isolated to scattered late afternoon and evening showers and storms, mainly over the higher terrain. Due to the lack of low level moisture, any showers and storms that form will most likely produce sprinkles and gusty winds. With the potential for dry lighting there may be some fire weather concerns across portions of the CWA. On Monday, the upper high is expected to weaken and flatten which will allow an upper level disturbance and associated cool front to move across Northeastern Colorado. Increased moisture behind the front should allow for a better chance of showers and storms which should result in somewhat cooler temperatures. Nevertheless, temperatures should still be hot across the plains with high ranging between 95 to 100 degrees. On Tuesday, the models are showing the upper ridge retrograding southwestward into Arizona in response to a potent shortwave moving across the Northern Great Lakes. Consequently, the upper flow aloft over Colorado should turn more northwesterly opening the door for occasional upper level disturbances and cold fronts. This should result in some relief in the heat along with higher precipitation chances, especially along and east of the Continental Divide. By Friday, temperatures may warm back up above 90 degrees on the plains with decreased precipitation chances. && .AVIATION /18Z TAFS through 00Z Sunday/... Issued at 205 PM MDT Fri Jul 12 2024 VFR conditions thru the period. Gusty north winds this aftn should become more northeast by 00Z and then decrease. Winds by mid evening will transition to a southerly direction. By 10z they may become light westerly. On Sat, winds will become north by late morning and then northeast by early aftn. There could be some virga late in the aftn with gusty microburst winds possible after 21z. && .FIRE WEATHER... Issued at 205 PM MDT Fri Jul 12 2024 Elevated fire danger will be in place across the plains foothills and higher valleys on Saturday due to hot and dry conditions along with low humidity levels. However, winds will be relatively light in most areas. && .BOU WATCHES/WARNINGS/ADVISORIES... Heat Advisory until 8 PM MDT this evening for COZ038>040-043. Heat Advisory from 10 AM to 8 PM MDT Saturday for COZ038>040- 042>051. Heat Advisory from 10 AM to 8 PM MDT Sunday for COZ038>040- 042>051. && $$ SHORT TERM...RPK LONG TERM...JK AVIATION...RPK FIRE WEATHER...RPK