Area Forecast Discussion
Issued by NWS Denver/Boulder, CO
Issued by NWS Denver/Boulder, CO
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812 FXUS65 KBOU 201816 AFDBOU Area Forecast Discussion National Weather Service Denver/Boulder CO 1216 PM MDT Thu Jun 20 2024 .KEY MESSAGES... - Warmer today with a good chance of afternoon thunderstorms. A few severe storms will be possible mainly across the plains. Locally heavy rainfall will occur in some areas as well. - Scattered to likely showers and thunderstorms on Friday. A few could be strong to severe, and also produce locally heavy rain. - Hotter and drier this weekend into next week. && .UPDATE... Issued at 1053 AM MDT Thu Jun 20 2024 Minimal sky cover this morning are allowing temperatures to warm efficiently into the 70s and low 80s across the lower elevations. The current temperature at the Denver airport is 89, already 9 degrees warmer than the high yesterday. With that being said, it will be much warmer today than yesterday with highs in mid-upper 80s, approaching 90 in spots on the plains. Made a minor increase in highs today. Satellite shows cumulus developing in the mountains, foothills, and the far northeast corner and this will increase across northeast Colorado as the surface heats more and the atmosphere becomes more unstable. Scattered thunderstorms are expected this afternoon into this evening with a few strong to severe storms. There is potential for another wave of showers/storms later in the evening, so minor edits to precip. prob. grids were made to reflect this. && .SHORT TERM /Through tonight/... Issued at 300 AM MDT Thu Jun 20 2024 A disturbance embedded in SW flow aloft is moving across the area early this morning. Most of the shower and tstm activity with this feature will move across srn areas of CWA thru 12z. For later today, sfc low pres will develop along the front range with increasing southerly low level flow across the plains. Deeper low level moisture has already overspread the plains. Overall, showers and storms will increase by early aftn over the higher terrain. Outflow boundaries from this activity will trigger additional development by mid aftn along the I-25 Corridor which will then spread across the plains by late aftn into the early evening hours. MLCAPE over the plains will be in the 1500-2000 j/kg range this aftn with a favorable enough shear profile for a few svr storms. Meanwhile, storms over the higher terrain may produce a few wind gusts up to 60 mph as well. Although storms will be moving, they could produce from 1.00 to 1.5 inches of rain in a rather short period of time as well. As far as highs today, readings will be warmer with readings in the 85 to 90 degree range over nern CO. For tonight, there is some indication of a another disturbance moving across overnight. This feature may allow for the development of additional shower and tstm development especially over the higher terrain. && .LONG TERM /Friday through Wednesday/... Issued at 330 AM MDT Thu Jun 20 2024 Upper ridging returns to dominate the CWA`s weather by Friday. This will continue well into next week, at least. Southwesterly flow aloft is progged for the forecast area Friday into Saturday, It becomes more zonal Saturday afternoon and night. The QG Omega fields indicate weak upward synoptic scale energy for the CWA Friday and Friday evening. Then weak downward vertical velocity is progged Saturday and Saturday evening, with benign conditions after that. There looks to be weak surge of slightly cooler air and upslope flow on Friday, at least for the plains. Models continue to show plenty of moisture for the CWA on Friday with precipitable water values in the 0.80 inch to 1.50 inches range in the afternoon and evening. Again, there is fairly decent CAPE progged Friday, especially over the northern and eastern border areas of the CWA. Moisture looks to decrease on Saturday with the PWs dropping into the 0.50 to 1.00 inch range. That along with the weak subsidence should lessen pops from Friday`s numbers. For temperatures, Friday`s highs look to be close to this afternoon`s expected highs, perhaps 0-1.5 C cooler. Saturday`s highs are 1.5-4.0 C warmer than Friday`s. For the later days, Sunday through Wednesday, models show upper ridging over Colorado all four days with the center of the upper high just sough of the state. The synoptic scale energy is benign to weak subsident all four days. There is enough moisture for rounds of late day showers and thunderstorms, with the best chances in the mountains and foothills. Temperatures look to be above seasonal normals all four days, with highs in the mid 90s to 100 degree F for the plains each afternoon. && .AVIATION /18Z TAFS through 18Z Friday/... Issued at 1216 AM MDT Thu Jun 20 2024 Enhanced southerly winds expected this afternoon with gusts 20-25 kts. Scattered thunderstorms develop and moves eastward this afternoon, mainly in the 20-00Z timeframe. Any nearby or passing thunderstorms may bring variable gusty winds up to 40 kts, potentially closer to 45 kts in any stronger storms. Heavy rain may also bring reduced visibilities/ceilings for short periods. After 00Z, there is a chance for another round of lower coverage scattered showers or storms through midnight. Friday, light and variable winds in the morning become east in the afternoon. Scattered thunderstorms develop in the afternoon around the terminals. && .HYDROLOGY... Issued at 300 AM MDT Thu Jun 20 2024 Although storms will be moving this afternoon and evening, the threat of heavy rainfall will be greater with an elevated threat of flash flooding in the burn scars. Across the plains, where rather high precipitable water levels will be in place, rainfall amounts of 1 to 1.5 inches in a short period of time will certainly be possible with isolated higher amounts. There could also be decent rainfall late day Friday, and the burn scars will be most susceptible to flash flooding. Pops will be lower Saturday and Sunday so the flash flooding threat will be decreased somewhat those days. && .BOU WATCHES/WARNINGS/ADVISORIES... None. && $$ UPDATE...Mensch SHORT TERM...RPK LONG TERM....RJK AVIATION...Mensch HYDROLOGY....RJK/RPK