


Area Forecast Discussion
Issued by NWS Denver/Boulder, CO
Issued by NWS Denver/Boulder, CO
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905 FXUS65 KBOU 071137 AFDBOU Area Forecast Discussion National Weather Service Denver/Boulder CO 537 AM MDT Mon Jul 7 2025 .KEY MESSAGES... - Scattered afternoon/evening thunderstorms today, most numerous over the eastern plains. - Some strong to severe storms are possible with large hail and damaging wind gusts, mainly across the eastern plains. - Hot temperatures expected Wednesday with the upper 90s expected across the plains. It is possible the hot temperatures extend into Thursday. && .UPDATE... Issued at 300 AM MDT Mon Jul 7 2025 Upper level ridging begins to intensify over the region today (continuing through Wednesday). With warming temperatures aloft and slight drying, thunderstorm activity is expected to decrease across the higher terrain and also along the I-25 urban corridor today. There still should be enough moisture and instability this afternoon for high-based thunderstorms. As the storms progress eastward, storms encounter an increasingly unstable and more moist airmass. Storms are expected to intensify with a few becoming severe with large hail and winds to 60 mph. A shortwave trough moves southeast across the Northern Plains today. This is expected to produce a line of thunderstorms across Nebraska, which may clip northeast Colorado as the line dives southeast. Storms are expected to shift east of the area early this evening with the area storm free around sunset. && .DISCUSSION /Through Sunday/... Issued at 238 PM MDT Sun Jul 6 2025 Satellite and radar show two main areas of convection this afternoon. One area is along a boundary that has setup from near Woodrow in western Washington County across to Kiowa. There are good levels of instability feeding these storms with mixed-layer CAPE around 1,500 j/kg. Strong updrafts have formed along this boundary as a result. The issue these storms are currently having with reaching severe limits is the lack of deep layer shear. Surface to 6 km shear values are around 25 knots so storms may struggle to maintain updrafts long enough to produce severe hail although a report or two of 1" hail is possible. However, severe wind gusts will be possible out of these storms throughout the afternoon and evening given steep lapse rates and downdraft CAPE around 1,700-1,800 j/kg. The other area of storms is along and just south of the Cheyenne Ridge. This area will have the potential for storms to congeal into a line as it heads east from around Cheyenne, WY. As it heads further east, the instability will increase with mixed-layer CAPE around 2,000 j/kg over the far northeast corner of Colorado. It is expected that these storms will produce damaging wind gusts up to 70 mph. A Severe Thunderstorm Watch has been issued for areas along and east of I-25 until 8pm tonight. Denver County was withheld from this watch as dew points have dropped to the low 40 there and instability is lower than other areas. Some model guidance is showing that storms could continue into the overnight hours tonight across the eastern plains. That threat will depend on how much instability the storms this afternoon and evening "use up." If there are fewer storms this afternoon and evening, scattered coverage of storms could occur after midnight. However, it is more likely that only a stray storm or two forms. Better moisture will stay in place over the eastern plains on Monday with dew point values in the low 60s from Akron and eastward. With steep lapse rates, most unstable CAPE values are forecast to exceed 3,000 j/kg in the northeast corner of Colorado. This is ample instability for strong to severe storms to form. The uncertainty with Monday`s forecast will come from the amount of shear and what boundaries are left behind from overnight convection. A weak shortwave aloft will enhance deep layer shear with values around 35 knots across the far northeast corner. These factors will lead to the development of an MCS that could produce severe wind gusts up to 70 mph mainly east of a line from Fort Morgan to Limon. SPC has an enhanced risk of severe weather and it seems reasonable for the far northeast corner. The Denver metro and I-25 corridor will mostly likely avoid much of the severe weather assuming the best moisture stays further east. The axis of an upper level ridge will move northeastward into Colorado on Tuesday. This will increase temperatures aloft and will decrease the chance for storms. However, enough lingering moisture could produce an isolated storm near the Cheyenne Ridge. High temperatures will begin to warm up to the mid 90s across the plains. Wednesday is still on track to be the warmest day of the upcoming week as the best subsidence and warmest air aloft will be overhead that day. Temperature forecasts still have Denver flirting with 100 degrees. With the NBM and ECMWF MOS mean forecasting a high of 98, the forecast was left at that number. However, Denver does have a chance of reaching the record daily high temperature of 100 degrees. A Heat Advisory may be needed especially if it appears cloud cover will be minimal. Models have converged on a trough moving through our forecast area on Thursday but this may only reduce the heat by 2-4 degrees from Wednesday. A cold front moves through Thursday night with much cooler conditions on Friday. && .AVIATION /12Z TAFS through 12Z Tuesday/... Issued at 537 AM MDT Mon Jul 7 2025 Southerly winds to continue through mid morning and then decrease as they turn northwesterly around 15Z. Isolated/scattered afternoon thunderstorms are expected with the best time frame 20-23Z. Gusty outflow winds producing wind shifts will be the main threat. Storms are expected to be east of the Denver area by 00Z Tuesday. East to northeast winds around 00Z turn southeast and then eventually southwest Monday evening/night. && .BOU WATCHES/WARNINGS/ADVISORIES... None. && $$ UPDATE...Meier DISCUSSION...Danielson AVIATION...Meier