218 FXUS65 KBOU 042324 AFDBOU Area Forecast Discussion National Weather Service Denver/Boulder CO 524 PM MDT Thu Jun 4 2026 .KEY MESSAGES... - Warm and mostly dry for today and Friday with only a slight chance of thunderstorms. - Afternoon high temps to reach the mid 90s across the plains this weekend. - An early season heat wave possible Tuesday through Thursday of next week with highs of 100 degrees possible in Denver and across the plains. && .DISCUSSION /Through Thursday/... Issued at 138 PM MDT Thu Jun 4 2026 Temperatures are well above normal with many areas in the mid 80s this afternoon and on their way to the upper 80s. Across most of our CWA, the moisture has mixed out and any showers and weak storms that do form, will generally produce gusty winds and little rain at the surface. The one exception is the far northeast plains where moisture hasn't mixed out. Sterling currently has a temperature of 90, a dew point of 50, and southeast winds which indicates moderate surface based CAPE and decent upslope flow. With northwest winds in Cheyenne and along much of the Cheyenne Ridge, there is a surface convergence zone that may create strong storms in northeast Weld, Logan, Phillips, and Sedgwick Counties later this afternoon/evening. The SPC mesoanalysis page shows effective bulk shear of around 30 knots which could support a severe storm or two in that area with large hail and damaging winds possible. There is currently a cold front in northeast Wyoming that will generate strong storms and eventually an outflow boundary that will reinforce the cold front late tonight. This front will move across northeast Colorado on Friday morning and it will keep conditions on Friday afternoon slightly cooler than today and will increase moisture. There will be moderate instability values but warm air aloft will result in an inversion that will greatly limit shower and thunderstorm activity. The best chance for showers and storms will be over the Palmer Divide and into Lincoln County where low level convergence will help to produce forcing that could overcome the cap. It's possible a few wind gusts around 50 mph are reported from these storms. The summer heat will begin Saturday and there may be no turning back. Flow aloft will turn southwesterly with warm 700 mb temperatures moving over Colorado. With the jet stream to the west of Colorado, there will be compressional heating that will push temperatures toward record values. The daily record high is 95 on Saturday most recently set in 2018 and that has a chance of being tied. The daily record high is 98 on Sunday set most recently in 2006 and the high may come within a degree or two of that temperature. This heat is occurring early in the season which could put added stress on people who plan to be outside for a majority of the day. Therefore, there was consideration for a Heat Advisory but no advisory was issued due to temperatures likely topping out in the mid 90s. If the forecast increases to the upper 90s, there may be a higher chance of an advisory issuance. There is a wider range of forecast high temperatures in the ensemble data on Monday due to the uncertainty of a surface boundary moving through eastern Colorado. Surface boundaries often move through eastern Colorado when there is strong lee cyclogenesis and that appears to be the likely scenario. Therefore, forecast high temperatures are in the upper 80s for most of the plains with a chance of storms mentioned. However, it is possible the southwest flow aloft is too strong for much of a surface boundary to make it through eastern Colorado and another day of heat occurs with highs in the mid 90s. There is growing confidence in record-breaking heat Tuesday through Thursday of next week that may require Heat Advisories. A strong ridge aloft will develop over the Central Plains of the US while a trough moves over the West Coast. Colorado will be in- between these two features which will lead to subsident flow. The ensemble data is starting to get confident that Denver and most of the rest of the urban corridor will reach the mid to upper 90s on Tuesday and Wednesday. The record high of 95 on Tuesday seems likely to be broken while the record high of 99 on Wednesday is within reach. The 50th percentile for the high temperature at KDEN on Thursday is 100 F on the 12Z euro ensembles. That is significant warmth at this time range and if Denver does reach 100 F, it would tie for the earliest 100-degree day in Denver history. && .AVIATION /00Z TAFS through 00Z Saturday/... Issued at 520 PM MDT Thu Jun 4 2026 VFR conditions are expected throughout the TAF period. Radar for the last several hours has shown scattered virga showers with gusty outflow winds mainly south of KDEN, including at KAPA which gusted near 30 kts around 22z. Winds will turn to drainage tonight and should remain at 10 kts or less. Winds will then turn to northerly tomorrow morning around 13z to 15z as a cold front pushes through from north to south. The front could move through slightly earlier. Winds will then be NE to near easterly for much of tomorrow afternoon after about 18z at all three sites. For tomorrow afternoon, there is a lower chance than this afternoon (10-20%) of virga showers with gusty outflow winds. The highest chance for this is to the south and west of KDEN (closer to KAPA and KBJC). Have not added in a prob30 at this time as confidence is still too low. Mid and high-level cloud cover will increase in the afternoon, as well. Winds may not turn fully to drainage tomorrow night, but instead stay more SE in the early overnight period at 10 kts or less. && .BOU WATCHES/WARNINGS/ADVISORIES... None. && $$ DISCUSSION...Danielson AVIATION...MV