586
UXUS97 KBOU 260118
SRGBOU
SOARING FORECAST
NATIONAL WEATHER SERVICE DENVER/BOULDER, COLORADO
1917 MDT FRIDAY, APRIL 25, 2025
THIS FORECAST IS FOR SATURDAY, APRIL 26, 2025:
IF THE TRIGGER TEMPERATURE OF 62.9 F/17.1 C IS REACHED...THEN
THERMAL SOARING INDEX....................... POOR
MAXIMUM RATE OF LIFT........................ 114 FT/MIN (0.6 M/S)
MAXIMUM HEIGHT OF THERMALS.................. 12619 FT MSL (7310 FT AGL)
FORECAST MAXIMUM TEMPERATURE................... 73.0 F/23.2 C
TIME OF TRIGGER TEMPERATURE.................... 1130 MDT
TIME OF OVERDEVELOPMENT........................ NONE
MIDDLE/HIGH CLOUDS DURING SOARING WINDOW....... BROKEN/OVERCAST OPAQUE MIDDLE
SURFACE WINDS DURING SOARING WINDOW............ 20 MPH OR LESS
HEIGHT OF THE -3 THERMAL INDEX................. 10620 FT MSL (5311 FT AGL)
THERMAL SOARING OUTLOOK FOR SUNDAY 04/27....... EXCELLENT
WAVE SOARING INDEX............................. POOR
WAVE SOARING INDEX TREND (TO 1800 MDT)......... NO CHANGE
HEIGHT OF STABLE LAYER (12-18K FT MSL)......... NONE
WEAK PVA/NVA (THROUGH 1800 MDT)................ WEAK PVA
POTENTIAL HEIGHT OF WAVE....................... 44865 FT MSL (39556 FT AGL)
WAVE SOARING OUTLOOK FOR SUNDAY 04/27.......... POOR
REMARKS...
SUNRISE/SUNSET.................... 06:05:30 / 19:48:53 MDT
TOTAL POSSIBLE SUNSHINE........... 13 HR 43 MIN 22 SEC (823 MIN 22 SEC)
ALTITUDE OF SUN AT 12:57:12 MDT... 64.01 DEGREES
UPPER AIR DATA FROM NUMERICAL MODEL FORECAST VALID ON 04/26/2025 AT 0600 MDT
FREEZING LEVEL.................. 12954 FT MSL (7645 FT AGL)
CONVECTIVE CONDENSATION LEVEL... 13830 FT MSL (8521 FT AGL)
LIFTED CONDENSATION LEVEL....... 13626 FT MSL (8317 FT AGL)
LIFTED INDEX.................... -3.1
K INDEX......................... +15.7
HEIGHT TEMPERATURE WIND WIND SPD LAPSE RATE CONVECTIONT THERMAL LIFT RATE
FT MSL DEG C DEG F DIR KT M/S C/KM F/KFT DEG C DEG F INDEX FPM M/S
--------------------------------------------------------------------------------
50000 -60.8 -77.4 240 39 20 -2.4 -1.3 M M M M M
45000 -64.3 -83.7 230 69 35 -0.0 -0.0 M M M M M
40000 -61.7 -79.1 225 72 37 1.7 1.0 M M M M M
38000 -58.7 -73.7 225 69 36 6.6 3.6 M M M M M
36000 -54.8 -66.6 225 65 33 6.6 3.6 M M M M M
34000 -50.7 -59.3 225 60 31 7.5 4.1 M M M M M
32000 -46.2 -51.2 225 55 28 7.5 4.1 M M M M M
30000 -40.9 -41.6 225 50 26 8.2 4.5 34.3 93.7 8.7 M M
29000 -38.5 -37.3 225 47 24 8.2 4.5 33.6 92.5 8.3 M M
28000 -36.0 -32.8 230 44 23 8.2 4.5 33.1 91.5 8.0 M M
27000 -33.6 -28.5 230 42 22 8.0 4.4 32.5 90.5 7.6 M M
26000 -31.2 -24.2 230 42 21 8.0 4.4 31.7 89.1 7.1 M M
25000 -28.9 -20.0 225 41 21 8.0 4.4 31.1 88.0 6.6 M M
24000 -26.5 -15.7 225 40 21 8.0 4.4 30.5 87.0 6.2 M M
23000 -24.1 -11.4 225 39 20 8.0 4.4 29.8 85.7 5.7 M M
22000 -21.6 -6.9 230 38 20 8.0 4.4 29.3 84.7 5.3 M M
21000 -19.3 -2.7 230 38 19 7.3 4.0 28.6 83.4 4.8 M M
20000 -17.1 1.2 230 37 19 7.3 4.0 27.7 81.8 4.1 M M
19500 -16.1 3.0 230 37 19 7.3 4.0 27.3 81.1 3.8 M M
19000 -15.0 5.0 230 37 19 7.4 4.1 26.9 80.4 3.4 M M
18500 -13.9 7.0 230 37 19 6.6 3.6 26.4 79.6 3.0 M M
18000 -13.0 8.6 230 36 18 6.8 3.7 25.9 78.6 2.6 M M
17500 -12.0 10.4 235 35 18 7.8 4.3 25.4 77.7 2.1 M M
17000 -10.7 12.7 235 34 17 9.0 4.9 25.2 77.4 2.0 M M
16500 -9.3 15.3 235 32 17 9.0 5.0 25.1 77.2 1.9 M M
16000 -8.0 17.6 235 30 15 8.5 4.7 24.9 76.9 1.7 M M
15500 -6.1 21.0 235 24 13 8.6 4.7 24.6 76.4 1.4 M M
15000 -4.9 23.2 230 21 11 8.7 4.8 24.5 76.0 1.3 M M
14500 -3.6 25.5 230 18 9 8.7 4.8 24.3 75.7 1.1 M M
14000 -2.3 27.9 230 17 9 8.5 4.7 24.1 75.4 0.9 M M
13500 -1.1 30.0 230 17 9 8.7 4.8 23.9 75.0 0.7 M M
13000 0.1 32.2 230 17 9 6.5 3.6 23.6 74.4 0.4 M M
12500 1.0 33.8 225 17 9 6.7 3.7 23.0 73.5 -0.2 498 2.5
12000 1.8 35.2 225 18 9 5.3 2.9 22.5 72.4 -0.8 458 2.3
11500 2.5 36.5 220 20 10 5.2 2.8 21.7 71.1 -1.6 423 2.2
11000 3.1 37.6 215 22 11 4.9 2.7 21.0 69.7 -2.4 389 2.0
10500 3.8 38.8 215 25 13 5.6 3.1 20.2 68.3 -3.3 354 1.8
10250 4.1 39.4 215 27 14 2.0 1.1 19.8 67.6 -3.7 337 1.7
10000 4.1 39.4 215 28 14 2.3 1.3 19.1 66.3 -4.4 329 1.7
9750 4.5 40.1 215 29 15 6.3 3.5 18.7 65.7 -4.8 311 1.6
9500 4.9 40.8 215 31 16 5.1 2.8 18.4 65.1 -5.1 292 1.5
9250 5.2 41.4 215 32 16 6.2 3.4 18.0 64.5 -5.5 274 1.4
9000 5.7 42.3 215 32 16 6.5 3.6 17.8 64.1 -5.8 252 1.3
8750 6.2 43.2 215 31 16 5.5 3.0 17.5 63.5 -6.1 232 1.2
8500 6.6 43.9 215 31 16 6.0 3.3 17.2 62.9 -6.4 212 1.1
8250 7.0 44.6 215 30 16 3.7 2.0 16.9 62.3 -6.8 193 1.0
8000 7.1 44.8 215 28 15 1.2 0.7 16.2 61.2 -7.3 181 0.9
7750 7.2 45.0 215 27 14 1.8 1.0 15.6 60.1 -8.0 170 0.9
7500 7.4 45.3 215 26 13 1.3 0.7 15.0 59.0 -8.6 159 0.8
7250 7.4 45.3 210 25 13 0.4 0.2 14.3 57.8 -9.3 149 0.8
7000 7.4 45.3 205 24 12 -0.8 -0.4 13.6 56.4 -10.0 142 0.7
6750 7.4 45.3 200 24 12 2.2 1.2 12.8 55.1 -10.8 135 0.7
6500 7.6 45.7 195 24 12 -1.8 -1.0 12.2 54.0 -11.4 123 0.6
6250 7.1 44.8 190 21 11 -8.1 -4.5 11.0 51.8 -12.6 130 0.7
6000 6.5 43.7 185 18 9 -7.4 -4.1 9.7 49.5 -14.0 139 0.7
5750 6.0 42.8 180 15 8 -7.1 -3.9 8.4 47.2 -15.3 149 0.8
5500 5.4 41.7 175 10 5 -10.7 -5.9 7.1 44.7 -16.6 160 0.8
* * * * * * NUMERICAL WEATHER PREDICTION MODEL FORECAST DATA VALID * * * * * *
04/26/2025 AT 0900 MDT | 04/26/2025 AT 1200 MDT
|
CAPE... 0.0 LI... +2.3 | CAPE... +87.4 LI... -0.0
CINH... 0.0 K INDEX... +11.2 | CINH... -77.7 K INDEX... +3.5
|
HEIGHT TEMPERATURE WND WNDSPD LAPSE RATE | TEMPERATURE WND WNDSPD LAPSE RATE
FT MSL DEG C DEG F DIR KT M/S C/KM F/KFT | DEG C DEG F DIR KT M/S C/KM F/KFT
--------------------------------------------------------------------------------
50000 -60.0 -76.0 245 34 18 -2.0 -1.1 | -59.8 -75.6 240 33 17 -1.7 -1.0
45000 -62.9 -81.2 240 67 34 0.8 0.5 | -62.4 -80.3 245 62 32 -0.0 -0.0
40000 -62.1 -79.8 225 70 36 0.6 0.3 | -62.7 -80.9 230 59 30 -0.1 -0.1
38000 -59.4 -74.9 225 68 35 6.6 3.6 | -60.0 -76.0 230 57 29 6.9 3.8
36000 -55.4 -67.7 225 63 33 6.6 3.6 | -55.8 -68.4 230 54 28 6.9 3.8
34000 -51.2 -60.2 225 59 30 8.1 4.4 | -51.4 -60.5 230 51 26 8.4 4.6
32000 -46.3 -51.3 230 54 28 8.1 4.4 | -45.7 -50.3 230 48 25 8.4 4.6
30000 -40.9 -41.6 230 50 26 8.0 4.4 | -40.6 -41.1 235 46 24 8.4 4.6
29000 -38.5 -37.3 230 48 25 8.0 4.4 | -38.1 -36.6 235 44 23 8.4 4.6
28000 -36.1 -33.0 230 46 24 8.1 4.4 | -35.6 -32.1 235 43 22 8.4 4.6
27000 -33.7 -28.7 230 45 23 8.0 4.4 | -33.2 -27.8 235 42 22 7.7 4.2
26000 -31.3 -24.3 230 43 22 8.0 4.4 | -30.9 -23.6 230 41 21 7.7 4.2
25000 -28.9 -20.0 230 41 21 8.0 4.4 | -28.6 -19.5 230 41 21 7.7 4.2
24000 -26.5 -15.7 230 40 21 8.1 4.5 | -26.3 -15.3 230 40 21 7.7 4.2
23000 -24.1 -11.4 230 39 20 8.1 4.5 | -24.0 -11.2 230 39 20 7.7 4.2
22000 -21.6 -6.9 230 39 20 8.1 4.5 | -21.7 -7.1 230 38 19 7.8 4.3
21000 -19.2 -2.6 230 38 20 7.8 4.3 | -19.3 -2.7 230 36 19 8.0 4.4
20000 -16.9 1.6 235 36 19 7.8 4.3 | -16.9 1.6 230 34 18 8.1 4.4
19500 -15.7 3.7 235 35 18 7.8 4.3 | -15.6 3.9 230 33 17 8.1 4.4
19000 -14.5 5.9 235 34 18 8.0 4.4 | -14.4 6.1 230 32 17 8.2 4.5
18500 -13.5 7.7 235 33 17 6.1 3.4 | -13.3 8.1 230 31 16 7.2 4.0
18000 -12.5 9.5 235 32 16 6.3 3.4 | -12.2 10.0 235 30 16 7.2 4.0
17500 -11.6 11.1 240 30 16 6.5 3.5 | -11.1 12.0 235 29 15 7.0 3.8
17000 -10.6 12.9 240 29 15 6.7 3.6 | -10.1 13.8 235 28 14 6.7 3.7
16500 -9.7 14.5 240 27 14 6.7 3.7 | -8.6 16.5 235 26 14 7.0 3.8
16000 -8.5 16.7 235 26 14 8.4 4.6 | -7.5 18.5 235 25 13 7.2 4.0
15500 -6.7 19.9 230 25 13 8.4 4.6 | -6.5 20.3 235 24 12 7.4 4.0
15000 -5.4 22.3 230 24 12 8.9 4.9 | -5.4 22.3 235 24 12 7.8 4.3
14500 -4.1 24.6 225 23 12 8.9 4.9 | -4.3 24.3 235 23 12 7.7 4.2
14000 -2.8 27.0 220 21 11 9.2 5.1 | -3.0 26.6 230 23 12 9.2 5.0
13500 -1.4 29.5 215 20 10 9.3 5.1 | -1.7 28.9 225 23 12 9.1 5.0
13000 -0.1 31.8 215 19 10 8.1 4.5 | -0.3 31.5 220 22 11 9.0 5.0
12500 1.1 34.0 215 16 8 8.2 4.5 | 1.0 33.8 215 21 11 9.0 4.9
12000 2.3 36.1 210 14 7 7.8 4.3 | 2.4 36.3 210 21 11 9.3 5.1
11500 3.4 38.1 215 12 6 7.9 4.3 | 3.8 38.8 205 20 10 9.5 5.2
11000 4.4 39.9 215 10 5 5.6 3.1 | 5.1 41.2 200 19 10 7.5 4.1
10500 5.1 41.2 215 11 6 5.6 3.0 | 6.1 43.0 200 18 9 6.6 3.6
10250 5.5 41.9 215 12 6 3.8 2.1 | 6.7 44.1 200 17 9 9.0 4.9
10000 5.7 42.3 215 12 6 3.8 2.1 | 7.3 45.1 200 16 8 7.7 4.2
9750 6.0 42.8 215 13 7 5.4 3.0 | 7.7 45.9 200 16 8 4.3 2.4
9500 6.4 43.5 215 15 7 5.2 2.9 | 8.0 46.4 200 16 8 5.3 2.9
9250 6.7 44.1 215 16 8 4.6 2.5 | 8.4 47.1 205 16 8 4.9 2.7
9000 7.0 44.6 215 17 9 3.8 2.1 | 8.7 47.7 205 16 8 3.7 2.0
8750 7.2 45.0 215 17 9 4.1 2.2 | 8.8 47.8 205 16 8 3.1 1.7
8500 7.5 45.5 215 18 9 4.5 2.5 | 9.0 48.2 205 16 8 2.9 1.6
8250 7.8 46.0 215 19 10 2.9 1.6 | 9.2 48.6 205 15 8 5.0 2.7
8000 7.9 46.2 215 19 10 1.3 0.7 | 9.6 49.3 200 14 7 7.7 4.2
7750 8.0 46.4 215 20 10 1.6 0.9 | 10.1 50.2 200 13 7 7.8 4.3
7500 8.1 46.6 215 20 10 1.4 0.8 | 10.6 51.1 200 13 7 8.3 4.6
7250 8.1 46.6 215 20 10 1.5 0.8 | 11.3 52.3 200 13 7 10.2 5.6
7000 8.2 46.8 210 19 10 1.5 0.8 | 12.1 53.8 200 12 6 11.4 6.2
6750 8.3 46.9 200 19 10 2.0 1.1 | 12.9 55.2 200 12 6 9.9 5.4
6500 8.5 47.3 190 19 10 3.0 1.6 | 13.6 56.5 200 12 6 10.1 5.6
6250 8.7 47.7 190 16 8 3.6 2.0 | 14.5 58.1 200 12 6 11.5 6.3
6000 9.0 48.2 185 14 7 2.6 1.4 | 15.3 59.5 200 11 6 11.2 6.1
5750 9.2 48.6 185 11 6 6.2 3.4 | 16.2 61.2 200 11 6 12.1 6.6
5500 10.1 50.2 185 9 5 17.7 9.7 | 17.3 63.1 200 10 5 20.4 11.2
04/26/2025 AT 1500 MDT | 04/26/2025 AT 1800 MDT
|
CAPE... +64.5 LI... +0.3 | CAPE... +1228.9 LI... -4.5
CINH... -53.2 K INDEX... +7.3 | CINH... -16.9 K INDEX... +28.9
|
HEIGHT TEMPERATURE WND WNDSPD LAPSE RATE | TEMPERATURE WND WNDSPD LAPSE RATE
FT MSL DEG C DEG F DIR KT M/S C/KM F/KFT | DEG C DEG F DIR KT M/S C/KM F/KFT
--------------------------------------------------------------------------------
50000 -60.4 -76.7 235 36 18 -1.0 -0.5 | -59.7 -75.5 240 39 20 -1.4 -0.8
45000 -61.8 -79.2 245 63 32 -0.1 -0.0 | -61.7 -79.1 250 64 33 0.4 0.2
40000 -62.1 -79.8 235 56 29 -0.1 -0.0 | -61.4 -78.5 245 61 31 0.3 0.2
38000 -59.4 -74.9 235 54 28 6.7 3.7 | -58.6 -73.5 240 56 29 6.6 3.6
36000 -55.4 -67.7 235 52 27 6.7 3.6 | -54.7 -66.5 240 50 26 6.6 3.6
34000 -51.0 -59.8 230 49 25 8.4 4.6 | -50.4 -58.7 235 45 23 8.0 4.4
32000 -46.0 -50.8 230 47 24 8.4 4.6 | -45.0 -49.0 235 41 21 8.0 4.4
30000 -40.4 -40.7 230 44 23 8.0 4.4 | -40.0 -40.0 235 38 20 8.5 4.7
29000 -38.0 -36.4 230 43 22 8.0 4.4 | -37.5 -35.5 235 38 19 8.5 4.7
28000 -35.6 -32.1 225 42 22 8.0 4.4 | -34.9 -30.8 235 37 19 8.5 4.7
27000 -33.2 -27.8 225 41 21 8.0 4.4 | -32.4 -26.3 235 36 19 7.8 4.3
26000 -30.8 -23.4 225 41 21 8.0 4.4 | -30.1 -22.2 240 36 19 7.8 4.3
25000 -28.4 -19.1 225 40 21 8.0 4.4 | -27.8 -18.0 240 36 18 7.8 4.3
24000 -26.0 -14.8 225 40 20 8.2 4.5 | -25.4 -13.7 240 36 18 8.0 4.4
23000 -23.6 -10.5 230 38 20 8.2 4.5 | -23.0 -9.4 240 37 19 8.0 4.4
22000 -21.1 -6.0 230 37 19 8.2 4.5 | -20.6 -5.1 240 38 19 8.0 4.4
21000 -18.7 -1.7 230 36 19 7.8 4.3 | -18.4 -1.1 245 38 20 6.8 3.7
20000 -16.4 2.5 230 35 18 7.9 4.3 | -16.4 2.5 245 38 20 6.9 3.8
19500 -15.2 4.6 230 34 18 7.9 4.3 | -15.4 4.3 245 38 20 6.9 3.8
19000 -14.0 6.8 230 34 17 7.8 4.3 | -14.3 6.3 245 38 20 6.8 3.7
18500 -12.8 9.0 230 33 17 8.2 4.5 | -13.3 8.1 245 37 19 8.4 4.6
18000 -11.6 11.1 235 33 17 8.2 4.5 | -12.0 10.4 245 35 18 8.4 4.6
17500 -10.3 13.5 235 32 17 8.1 4.4 | -10.8 12.6 245 33 17 8.5 4.6
17000 -9.1 15.6 235 32 16 8.0 4.4 | -9.6 14.7 245 31 16 8.5 4.7
16500 -7.9 17.8 235 31 16 8.0 4.4 | -8.4 16.9 240 30 15 8.5 4.7
16000 -6.3 20.7 240 30 16 7.1 3.9 | -6.5 20.3 240 29 15 8.6 4.7
15500 -5.3 22.5 235 29 15 7.1 3.9 | -5.3 22.5 235 28 15 8.5 4.7
15000 -4.2 24.4 235 28 15 7.1 3.9 | -4.1 24.6 230 28 14 7.8 4.3
14500 -3.2 26.2 235 28 14 7.2 4.0 | -3.0 26.6 230 28 14 7.9 4.3
14000 -2.2 28.0 230 27 14 6.3 3.4 | -1.8 28.8 225 27 14 8.0 4.4
13500 -1.3 29.7 230 27 14 6.4 3.5 | -0.6 30.9 220 27 14 7.9 4.4
13000 -0.4 31.3 225 26 14 7.2 3.9 | 0.6 33.1 215 26 14 8.6 4.7
12500 0.6 33.1 215 25 13 7.3 4.0 | 1.9 35.4 215 26 14 8.7 4.8
12000 1.7 35.1 210 24 12 8.9 4.9 | 3.2 37.8 210 26 13 9.0 4.9
11500 3.0 37.4 205 22 11 9.3 5.1 | 4.5 40.1 205 26 13 9.1 5.0
11000 4.4 39.9 200 20 11 8.9 4.9 | 5.8 42.4 205 26 13 8.4 4.6
10500 5.7 42.3 195 20 10 8.1 4.4 | 7.0 44.6 200 26 13 7.5 4.1
10250 6.3 43.3 195 20 10 11.4 6.3 | 7.6 45.7 200 26 13 10.8 5.9
10000 7.3 45.1 195 20 10 12.1 6.6 | 8.5 47.3 195 26 14 10.6 5.8
9750 8.0 46.4 195 20 10 9.3 5.1 | 9.1 48.4 195 27 14 7.1 3.9
9500 8.8 47.8 195 20 10 9.9 5.4 | 9.6 49.3 190 28 14 7.9 4.3
9250 9.5 49.1 195 19 10 10.2 5.6 | 10.2 50.4 190 29 15 8.4 4.6
9000 10.3 50.5 195 19 10 10.1 5.5 | 10.8 51.4 185 29 15 7.2 4.0
8750 11.0 51.8 195 19 10 9.7 5.3 | 11.2 52.2 185 30 15 5.7 3.1
8500 11.7 53.1 195 19 10 9.5 5.2 | 11.6 52.9 180 30 16 5.7 3.1
8250 12.4 54.3 195 19 10 10.7 5.9 | 12.0 53.6 180 31 16 7.3 4.0
8000 13.3 55.9 195 19 10 11.0 6.1 | 12.6 54.7 175 30 16 9.5 5.2
7750 14.1 57.4 195 18 9 9.6 5.3 | 13.2 55.8 175 30 15 8.9 4.9
7500 14.8 58.6 195 18 9 9.4 5.2 | 13.8 56.8 175 29 15 8.2 4.5
7250 15.5 59.9 190 18 9 10.4 5.7 | 14.5 58.1 175 29 15 9.9 5.4
7000 16.3 61.3 190 18 9 11.0 6.0 | 15.3 59.5 175 28 15 11.3 6.2
6750 17.1 62.8 190 18 9 9.6 5.3 | 16.1 61.0 175 28 14 9.5 5.2
6500 17.8 64.0 190 17 9 9.6 5.3 | 16.7 62.1 175 27 14 9.0 5.0
6250 18.5 65.3 190 17 9 10.9 6.0 | 17.5 63.5 175 26 14 10.9 6.0
6000 19.4 66.9 190 16 8 11.8 6.5 | 18.3 64.9 175 25 13 12.2 6.7
5750 20.2 68.4 190 16 8 9.4 5.2 | 19.2 66.6 170 23 12 10.1 5.5
5500 21.0 69.8 190 15 8 13.6 7.4 | 19.9 67.8 170 21 11 10.3 5.6
________________________________________________________________________________
THIS PRODUCT IS ISSUED TWICE PER DAY, ONCE BY APPROXIMATELY 0630 MST/0730 MDT
(1330 UTC) AND AGAIN BY APPROXIMATELY 1830 MST/1930 MDT (0130 UTC). IT IS NOT
CONTINUOUSLY MONITORED NOR UPDATED AFTER ITS INITIAL ISSUANCE.
THE INFORMATION CONTAINED HEREIN IS BASED ON RAWINSONDE OBSERVATION AND/OR
NUMERICAL WEATHER PREDICTION MODEL DATA TAKEN NEAR THE OLD STAPLETON
AIRPORT SITE IN DENVER, COLORADO AT
NORTH LATITUDE: 39 DEG 46 MIN 5.016 SEC
WEST LONGITUDE: 104 DEG 52 MIN 9.984 SEC
ELEVATION: 5285 FEET (1611 METERS)
AND MAY NOT BE REPRESENTATIVE OF OTHER AREAS ALONG THE FRONT RANGE OF THE
COLORADO ROCKY MOUNTAINS. NOTE THAT SOME ELEVATIONS IN NUMERICAL WEATHER
PREDICTION MODELS DIFFER FROM ACTUAL STATION ELEVATIONS, WHICH CAN LEAD TO
DATA WHICH APPEAR TO BE BELOW GROUND. ERRONEOUS DATA SUCH AS THESE SHOULD
NOT BE USED.
THE CONTENT AND FORMAT OF THIS REPORT AS WELL AS THE ISSUANCE TIMES ARE SUBJECT
TO CHANGE WITHOUT PRIOR NOTICE. COMMENTS AND SUGGESTIONS ARE WELCOME AND SHOULD
BE DIRECTED TO ONE OF THE ADDRESSES OR PHONE NUMBERS SHOWN AT THE BOTTOM OF THIS
PAGE. TO EXPEDITE A RESPONSE TO COMMENTS, BE SURE TO MENTION YOUR INTEREST IN
THE SOARING FORECAST.
DEFINITIONS:
CAPE (CONVECTIVE AVAILABLE POTENTIAL ENERGY) - AN INTEGRATED MEASURE OF THE
ENERGY AVAILABLE FOR CONVECTIVE DEVELOPMENT, ALSO KNOWN AS THE POSITIVE
AREA ON A THERMODYNAMIC DIAGRAM. UNITS ARE JOULES PER KILOGRAM. LARGER
VALUES ARE INDICATIVE OF GREATER INSTABILITY AND THE POSSIBILITY OF
STRONGER CONVECTIVE ACTIVITY, INCLUDING THUNDERSTORMS. VALUES AROUND OR
GREATER THAN 1000 SUGGEST THE POSSIBILITY OF SEVERE WEATHER SHOULD
CONVECTIVE ACTIVITY DEVELOP.
CINH (CONVECTIVE INHIBITION) - AN INTEGRATED MEASURE OF THE AMOUNT OF ENERGY
NEEDED TO INITIATE CONVECTIVE ACTIVITY, ALSO KNOWN AS THE NEGATIVE AREA ON
A THERMODYNAMIC DIAGRAM. UNITS ARE JOULES PER KILOGRAM. THE MORE NEGATIVE
THIS NUMBER, THE MORE ENERGY IS REQUIRED TO INITIATE CONVECTION. THIS
INHIBITIVE ENERGY CAN BE OVERCOME THROUGH SURFACE HEATING, COOLING ALOFT,
LIFTING MECHANISMS (OROGRAPHIC, FRONTAL, GRAVITY WAVES, ETC.)
CONVECTIVE CONDENSATION LEVEL - THE HEIGHT TO WHICH AN AIR PARCEL POSSESSING THE
AVERAGE SATURATION MIXING RATIO IN THE LOWEST 4000 FEET OF THE AIRMASS,
IF HEATED SUFFICIENTLY FROM BELOW, WILL RISE DRY ADIABATICALLY UNTIL IT
JUST BECOMES SATURATED. IT ESTIMATES THE BASE OF CUMULUS CLOUDS THAT ARE
PRODUCED BY SURFACE HEATING ONLY.
CONVECTION TEMPERATURE (CONVECTIONT) - THE SURFACE TEMPERATURE REQUIRED TO MAKE
THE AIRMASS DRY ADIABATIC UP TO THE GIVEN LEVEL. IT CAN BE CONSIDERED A
"TRIGGER TEMPERATURE" FOR THAT LEVEL.
FREEZING LEVEL - THE HEIGHT WHERE THE TEMPERATURE IS ZERO DEGREES CELSIUS.
HEIGHT OF STABLE LAYER - THE HEIGHT (BETWEEN 12,000 AND 18,000 FEET ABOVE
MEAN SEA LEVEL) WHERE THE SMALLEST LAPSE RATE EXISTS. THE LOCATION AND
EXISTENCE OF THIS FEATURE IS IMPORTANT IN THE GENERATION OF MOUNTAIN
WAVES.
K INDEX - A MEASURE OF STABILITY WHICH COMBINES THE TEMPERATURE DIFFERENCE
BETWEEN APPROXIMATELY 5,000 AND 18,000 FEET ABOVE THE SURFACE, THE AMOUNT
OF MOISTURE AT APPROXIMATELY 5,000 FEET ABOVE THE SURFACE, AND A MEASURE
OF THE DRYNESS AT APPROXIMATELY 10,000 FEET ABOVE THE SURFACE. LARGER
POSITIVE NUMBERS INDICATE MORE INSTABILITY AND A GREATER LIKELIHOOD OF
THUNDERSTORM DEVELOPMENT. ONE INTERPRETATION OF K INDEX VALUES REGARDING
SOARING IN THE WESTERN UNITED STATES IS GIVEN IN WMO TECHNICAL NOTE 158
AND IS REPRODUCED IN THE FOLLOWING TABLE:
BELOW -10 NO OR WEAK THERMALS
-10 TO 5 DRY THERMALS OR 1/8 CUMULUS WITH MODERATE THERMALS
5 TO 15 GOOD SOARING CONDITIONS
15 TO 20 GOOD SOARING CONDITIONS WITH OCCASIONAL SHOWERS
20 TO 30 EXCELLENT SOARING CONDITIONS, BUT INCREASING
PROBABILITY OF SHOWERS AND THUNDERSTORMS
ABOVE 30 MORE THAN 60 PERCENT PROBABILITY OF THUNDERSTORMS
LAPSE RATE - THE CHANGE WITH HEIGHT OF THE TEMPERATURE. NEGATIVE VALUES INDICATE
INVERSIONS.
LIFTED CONDENSATION LEVEL - THE HEIGHT TO WHICH AN AIR PARCEL POSSESSING THE
AVERAGE DEW POINT IN THE LOWEST 4000 FEET OF THE AIRMASS AND THE FORECAST
MAXIMUM TEMPERATURE MUST BE LIFTED DRY ADIABATICALLY TO ATTAIN SATURATION.
LIFTED INDEX (LI) - THE DIFFERENCE BETWEEN THE ENVIRONMENTAL TEMPERATURE AT A
LEVEL APPROXIMATELY 18,000 FEET ABOVE THE SURFACE AND THE TEMPERATURE OF
AN AIR PARCEL LIFTED DRY ADIABATICALLY FROM THE SURFACE TO ITS LIFTED
CONDENSATION LEVEL AND THEN PSEUDOADIABATICALLY THEREAFTER TO THIS SAME
LEVEL. THE PARCEL'S INITIAL TEMPERATURE IS THE FORECAST MAXIMUM
TEMPERATURE AND ITS DEW POINT IS THE AVERAGE DEW POINT IN THE LOWEST 4000
FEET OF THE AIRMASS. NEGATIVE VALUES ARE INDICATIVE OF INSTABILITY WITH
POSITIVE VALUES SHOWING STABLE CONDITIONS.
LIFT RATE - AN EXPERIMENTAL ESTIMATE OF THE STRENGTH OF THERMALS. IT IS
COMPUTED THE SAME WAY AS THE MAXIMUM RATE OF LIFT BUT USES THE ACTUAL
LEVEL RATHER THAN THE MAXIMUM HEIGHT OF THERMALS IN THE CALCULATION.
ALSO, NONE OF THE EMPIRICAL ADJUSTMENTS BASED ON CLOUDINESS AND K-INDEX
ARE APPLIED TO THESE CALCULATIONS.
MAXIMUM HEIGHT OF THERMALS - THE HEIGHT WHERE THE DRY ADIABAT THROUGH THE
FORECAST MAXIMUM TEMPERATURE INTERSECTS THE ENVIRONMENTAL TEMPERATURE.
MAXIMUM RATE OF LIFT - AN ESTIMATE OF THE MAXIMUM STRENGTH OF THERMALS. IT
IS COMPUTED FROM AN EMPIRICAL FORMULA WHICH COMBINES THE EXPECTED MAXIMUM
HEIGHT OF THERMALS WITH THE DIFFERENCE IN THE ENVIRONMENTAL TEMPERATURES
BETWEEN THE MAXIMUM HEIGHT OF THERMALS AND THE TEMPERATURE 4,000 FEET
ABOVE THE GROUND. AFTER THIS COMPUTATION, FURTHER EMPIRICAL ADJUSTMENTS
ARE MADE BASED ON THE VALUE OF THE K-INDEX AND THE AMOUNT AND OPACITY OF
MIDDLE AND HIGH LEVEL CLOUDINESS EXPECTED BETWEEN THE TIME OF TRIGGER
TEMPERATURE AND THE TIME OF OVERDEVELOPMENT.
MIDDLE/HIGH CLOUDS - THE AMOUNT AND OPACITY OF MIDDLE (ALTOSTRATUS, ALTOCUMULUS)
OR HIGH (CIRRUS, CIRROSTRATUS, CIRROCUMULUS) CLOUDS. BROKEN MEANS THAT
BETWEEN 60% AND 90% OF THE SKY IS COVERED BY THE CLOUD, WITH OVERCAST
CONDITIONS OCCURRING WHEN MORE THAN 90% OF THE SKY IS COVERED BY THE CLOUD.
THIN IMPLIES THAT THE CLOUDS ARE PREDOMINANTLY TRANSPARENT, MEANING THAT
SOME SUNLIGHT IS REACHING THE GROUND, IN CONTRAST TO OPAQUE WHICH SUGGESTS
THAT LITTLE SUNLIGHT IS REACHING THE GROUND.
POTENTIAL HEIGHT OF WAVE - THE MINIMUM OF THE FOLLOWING TWO HEIGHTS:
1. LEVEL ABOVE THE HEIGHT OF STABLE LAYER (OR 14,000 FEET IF NONE EXISTS)
WHERE THE WIND DIRECTION CHANGES BY 30 DEGREES OR MORE
2. LEVEL ABOVE THE HEIGHT OF STABLE LAYER (OR 14,000 FEET IF NONE EXISTS)
WHERE THE WIND SPEED NO LONGER INCREASES WITH HEIGHT
PVA/NVA - POSITIVE VORTICITY ADVECTION (PVA)/NEGATIVE VORTICITY ADVECTION (NVA)
ON THE 500 MILLIBAR ISOBARIC SURFACE (APPROXIMATELY 18,000 FEET ABOVE MEAN
SEA LEVEL). WEAK PVA HAS BEEN SHOWN TO ASSIST IN MOUNTAIN WAVE SOARING.
SOARING WINDOW - THE TIME BETWEEN THE TIME THE TRIGGER TEMPERATURE IS REACHED
AND THE TIME OF OVERDEVELOPMENT.
THERMAL INDEX - THE DIFFERENCE BETWEEN THE ENVIRONMENTAL TEMPERATURE AND THE
TEMPERATURE AT A PARTICULAR LEVEL DETERMINED BY FOLLOWING THE DRY ADIABAT
THROUGH THE FORECAST MAXIMUM TEMPERATURE UP TO THAT LEVEL. NEGATIVE VALUES
ARE INDICATIVE OF THERMAL LIFT.
THERMAL SOARING INDEX - AN ADJECTIVE RATING (FOR SAILPLANES) BASED ON THE
COMPUTED MAXIMUM RATE OF LIFT, AND THE WIND SPEED AND MIDDLE AND HIGH
CLOUD COVER EXPECTED DURING THE SOARING WINDOW (THE TIME OF THE TRIGGER
TEMPERATURE AND THE TIME OF OVERDEVELOPMENT) ACCORDING TO THE FOLLOWING:
MAXIMUM RATE OF LIFT ADJECTIVE RATING
>= 800 FPM EXCELLENT
>= 400 AND < 800 FPM GOOD
>= 200 AND < 400 FPM FAIR
< 200 FPM POOR
TIME OF OVERDEVELOPMENT - THE TIME ONE OR MORE OF THE FOLLOWING PHENOMENA,
WHICH ESSENTIALLY SHUT OFF THERMAL LIFT, IS EXPECTED TO OCCUR:
1. FORMATION OF BROKEN TO OVERCAST CONVECTIVE CLOUD COVER
2. FORMATION OF SCATTERED TO NUMEROUS DOWNBURSTS
3. INITIATION OF WIDESPREAD PRECIPITATION
TIME OF TRIGGER TEMPERATURE - THE TIME THE SURFACE TEMPERATURE IS EXPECTED TO
REACH THE TRIGGER TEMPERATURE.
TRIGGER TEMPERATURE - THE SURFACE TEMPERATURE REQUIRED TO MAKE THE FIRST 4000
FEET OF THE ATMOSPHERE DRY ADIABATIC.
WAVE SOARING INDEX - AN EMPIRICAL, ADJECTIVE RATING (FOR SAILPLANES) WHICH
ATTEMPTS TO COMBINE A VARIETY OF PHENOMENA IMPORTANT IN MOUNTAIN WAVE
SOARING INTO A SINGLE INDEX NUMBER. OBJECTIVE POINTS ARE ASSIGNED TO
THESE PHENOMENA: WIND SPEED AND DIRECTION AT 14,000 FT MSL, THE STATIC
STABILITY IN THE 12,000-18,000 FT MSL LAYER, THE WIND SPEED GRADIENT ABOVE
THE STABLE LAYER, JET STREAM LOCATION AND FRONTAL AND UPPER TROUGH
MOVEMENTS.
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