Area Forecast Discussion
Issued by NWS Denver/Boulder, CO
Issued by NWS Denver/Boulder, CO
Versions:
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
592 FXUS65 KBOU 290039 AFDBOU Area Forecast Discussion National Weather Service Denver/Boulder CO 639 PM MDT Fri Jun 28 2024 .KEY MESSAGES... - Scattered showers and storms could produce gusty conditions until early evening across the mountains to the plains. Expect wind gusts up to 50 mph. A severe storm cannot be ruled for the northeast corner which could produce small hail and wind gusts up to 60 mph. - Isolated to scattered thunderstorms this weekend, with a few strong to severe storms possible Sunday afternoon and evening. - Drier conditions possible by mid next week. && .SHORT TERM /Through Saturday/... Issued at 242 PM MDT Fri Jun 28 2024 CSU TIME SLICE sounding this afternoon displays weak shear and MLCAPE values near 400-500 J/kg. With large DCAPE values shown on CSU and ACARS soundings between 1000-1400 J/kg, any delayed convection that arrives will bring strong wind gusts up to 50 mph. CAMs favor scattered showers and storms rolling off the foothills into the plains between 4-8 PM MDT. In terms of severe chances, an isolated storm or two could produce wind gusts up to 60 mph and small hail but given our late warm up and dry soundings, the chances are low. Partly cloudy skies clear tonight. A few hours after midnight tonight, a cold front will sweep through the CWA. Northerly winds could produce wind gusts up to 20-30 mph briefly overnight. 700mb temperatures drop between 9-12C as much cooler air approaches from the north Saturday morning. Cold air advection will lead to a afternoon temperatures slightly below normal conditions. Expect low to mid 80s for the urban corridor and plains; low 60s to mid 70s for the mountains, foothills and valleys. Diurnal thunderstorms will develop once more mainly south of I-70 for areas such as South Park, Douglas, Elbert and Lincoln counties. These areas line up with SPC marginal risk of severe storms. With decent conditions for development such as steep mid- level rates between 7-8C/km, 25-30kt shear, and weak instability, it is possible a few storms could produce small hail, and gusty winds. && .LONG TERM /Saturday night through Friday/... Issued at 242 PM MDT Fri Jun 28 2024 Weak ridging aloft and subtle height rises increase mid-level temperatures on Sunday. This will support a rebound in temperatures back into the lower 90s across a good portion of the plains and urban corridor. MLCAPE values are marginal (< 1000 J/kg) with normal to slightly above normal moisture and weak ascent. The higher chances will more likely be in the mountains/foothills, Park County, and the Palmer Divide areas where the higher instability/moisture is. Model soundings across the east plains show sufficient instability, but are weakly capped, which may also thunderstorm development/coverage. Shear will be sufficient to support a few organized strong to severe thunderstorms. Early next week to mid-week, the main axis of an upper level trough positions to the west of Colorado. An upper jet situates to the north, putting CO in an area of weak ascent. Moisture ranges from above to just above average. As a result, each day will feature afternoon/evening chances for scattered, lower coverage thunderstorms with the higher chances for the higher terrain and Palmer Divide. Towards the end of the week, moisture gradually decreases as an upper ridge slowly pushes eastward across the western CONUS. && .AVIATION /00Z TAFS through 00Z Saturday/... Issued at 620 PM MDT Fri Jun 28 2024 Scattered showers and storms have formed this afternoon mainly over the higher terrain. Considering the hot and dry airmass over the terminals, these showers and storms are unlikely to have a direct impact. However, as they produce virga, strong winds will form with gusts around 40 knots possible. Given the strong instability and high moisture across the western slope of Colorado, showers and storms will continue well into the evening. This means that gusty winds could continue beyond the 04Z end time currently in the TAF although the majority of showers should come to an end around midnight. A cold front will move through the terminals around 07-09Z Saturday. There will be gusty north winds behind this front that could reach 30 knots. By 11Z, there will be better moisture that arrives from the north and with the northeast, upslope winds, stratus could form. The confidence in not very high in stratus forming but since it is slightly greater than 50%, a broken layer around 3 kft was included. Winds will be out of the southeast for most of the day tomorrow. While conditions are much more stable than previous days, a few light showers may form over the Denver metro. These could produce wind gusts up to 35 knots in the late afternoon/evening. && .BOU WATCHES/WARNINGS/ADVISORIES... None. && $$ SHORT TERM...AD LONG TERM...Mensch AVIATION...Danielson