193
UXUS97 KBOU 311227
SRGBOU
SOARING FORECAST
NATIONAL WEATHER SERVICE DENVER/BOULDER, COLORADO
0626 MDT MONDAY, AUGUST 31, 2026
THIS FORECAST IS FOR MONDAY, AUGUST 31, 2026:
IF THE TRIGGER TEMPERATURE OF 79.5 F/26.4 C IS REACHED...THEN
THERMAL SOARING INDEX....................... EXCELLENT
MAXIMUM RATE OF LIFT........................ 928 FT/MIN (4.7 M/S)
MAXIMUM HEIGHT OF THERMALS.................. 15705 FT MSL (10280 FT AGL)
FORECAST MAXIMUM TEMPERATURE................... 86.0 F/30.5 C
TIME OF TRIGGER TEMPERATURE.................... 1200 MDT
TIME OF OVERDEVELOPMENT........................ NONE
MIDDLE/HIGH CLOUDS DURING SOARING WINDOW....... OVERCAST OPAQUE HIGH
SURFACE WINDS DURING SOARING WINDOW............ 20 MPH OR LESS
HEIGHT OF THE -3 THERMAL INDEX................. 9927 FT MSL (4502 FT AGL)
THERMAL SOARING OUTLOOK FOR TUESDAY 09/01...... POOR
WAVE SOARING INDEX............................. POOR
WAVE SOARING INDEX TREND (TO 1800 MDT)......... SAME
HEIGHT OF STABLE LAYER (12-18K FT MSL)......... NONE
WEAK PVA/NVA (THROUGH 1800 MDT)................ NEITHER
POTENTIAL HEIGHT OF WAVE....................... 31511 FT MSL (26086 FT AGL)
WAVE SOARING OUTLOOK FOR TUESDAY 09/01......... GOOD
REMARKS...
SUNRISE/SUNSET.................... 06:26:59 / 19:32:27 MDT
TOTAL POSSIBLE SUNSHINE........... 13 HR 5 MIN 28 SEC (785 MIN 28 SEC)
ALTITUDE OF SUN AT 12:59:43 MDT... 58.65 DEGREES
UPPER AIR DATA FROM NUMERICAL MODEL FORECAST VALID ON 08/31/2026 AT 0600 MDT
FREEZING LEVEL.................. 15391 FT MSL (9966 FT AGL)
CONVECTIVE CONDENSATION LEVEL... 15260 FT MSL (9835 FT AGL)
LIFTED CONDENSATION LEVEL....... 15437 FT MSL (10012 FT AGL)
LIFTED INDEX.................... -0.8
K INDEX......................... +25.8
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 -62.0 -79.6 240 48 25 1.8 1.0 87.0 188.6 33.4 M M
45000 -58.9 -74.0 240 66 34 2.5 1.4 68.8 155.8 24.3 M M
40000 -53.9 -65.0 245 69 35 7.8 4.3 53.3 127.9 15.7 M M
38000 -49.2 -56.6 240 60 31 7.8 4.3 51.4 124.5 14.8 M M
36000 -44.5 -48.1 230 53 27 7.9 4.3 50.1 122.2 14.2 M M
34000 -39.7 -39.5 230 51 26 8.1 4.4 48.5 119.2 13.4 M M
32000 -34.8 -30.6 230 49 25 8.2 4.5 47.3 117.2 12.8 M M
30000 -30.3 -22.5 235 44 23 7.6 4.2 45.5 114.0 11.7 M M
29000 -28.0 -18.4 235 42 22 7.6 4.2 44.7 112.5 11.2 M M
28000 -25.7 -14.3 240 40 21 7.8 4.3 44.1 111.3 10.8 M M
27000 -23.4 -10.1 240 37 19 7.9 4.4 43.2 109.8 10.3 M M
26000 -21.0 -5.8 240 35 18 7.9 4.4 42.5 108.6 9.9 M M
25000 -18.6 -1.5 240 32 17 8.1 4.4 42.0 107.6 9.6 M M
24000 -16.1 3.0 240 31 16 6.6 3.6 40.6 105.0 8.5 M M
23000 -14.1 6.6 240 30 16 6.7 3.7 39.4 103.0 7.6 M M
22000 -12.2 10.0 245 29 15 6.1 3.3 38.4 101.2 6.8 M M
21000 -10.5 13.1 245 27 14 5.7 3.1 36.9 98.4 5.5 M M
20000 -8.8 16.2 250 24 12 5.8 3.2 35.5 95.9 4.3 M M
19500 -8.0 17.6 250 23 12 5.8 3.2 34.9 94.8 3.8 M M
19000 -7.2 19.0 255 21 11 5.7 3.2 34.2 93.5 3.2 M M
18500 -6.3 20.7 255 20 10 5.7 3.2 33.5 92.3 2.6 M M
18000 -5.5 22.1 255 18 9 6.5 3.6 32.8 91.1 2.0 M M
17500 -4.5 23.9 255 17 9 6.8 3.7 32.3 90.2 1.5 M M
17000 -3.5 25.7 260 16 8 6.9 3.8 31.8 89.3 1.0 M M
16500 -2.5 27.5 260 16 8 7.5 4.1 31.4 88.5 0.6 M M
16000 -1.4 29.5 260 15 8 7.4 4.1 31.0 87.8 0.2 M M
15500 -0.3 31.5 260 15 8 8.2 4.5 30.7 87.2 -0.1 909 4.6
15000 0.9 33.6 260 14 7 8.2 4.5 30.4 86.8 -0.4 858 4.4
14500 2.1 35.8 260 14 7 8.6 4.7 30.2 86.3 -0.7 808 4.1
14000 3.4 38.1 260 13 7 8.8 4.8 30.0 86.0 -0.8 754 3.8
13500 4.7 40.5 260 13 7 8.8 4.9 29.9 85.8 -1.0 701 3.6
13000 6.0 42.8 260 12 6 8.9 4.9 29.7 85.5 -1.2 647 3.3
12500 7.3 45.1 260 11 6 8.9 4.9 29.6 85.3 -1.3 592 3.0
12000 8.5 47.3 260 10 5 8.3 4.5 29.4 84.9 -1.5 540 2.7
11500 9.8 49.6 260 9 5 8.3 4.6 29.2 84.5 -1.8 488 2.5
11000 10.9 51.6 255 8 4 7.7 4.2 28.9 84.0 -2.1 439 2.2
10500 12.1 53.8 250 7 4 7.4 4.0 28.6 83.5 -2.4 390 2.0
10250 12.6 54.7 245 7 3 6.9 3.8 28.4 83.1 -2.6 367 1.9
10000 13.1 55.6 240 7 3 7.2 3.9 28.2 82.7 -2.8 345 1.8
9750 13.6 56.5 230 7 3 7.1 3.9 28.0 82.3 -3.1 322 1.6
9500 14.1 57.4 225 7 3 7.1 3.9 27.8 82.0 -3.3 299 1.5
9250 14.6 58.3 220 7 3 6.6 3.6 27.5 81.6 -3.5 277 1.4
9000 15.1 59.2 210 7 4 7.0 3.8 27.3 81.1 -3.8 255 1.3
8750 15.6 60.1 205 7 4 7.5 4.1 27.1 80.8 -4.0 232 1.2
8500 16.6 61.9 195 8 4 6.2 3.4 26.7 80.1 -4.4 187 0.9
8250 17.1 62.8 195 9 4 6.4 3.5 26.4 79.6 -4.7 166 0.8
8000 17.6 63.7 190 9 5 7.6 4.2 26.2 79.2 -5.0 143 0.7
7750 18.1 64.6 190 9 5 6.7 3.7 26.0 78.9 -5.2 119 0.6
7500 18.6 65.5 190 9 5 5.1 2.8 25.7 78.3 -5.5 99 0.5
7250 18.9 66.0 195 10 5 4.8 2.6 25.4 77.7 -5.9 81 0.4
7000 19.3 66.7 195 10 5 5.0 2.8 25.0 77.0 -6.2 63 0.3
6750 19.6 67.3 200 10 5 2.6 1.4 24.6 76.3 -6.7 46 0.2
6500 19.7 67.5 200 9 5 0.4 0.2 23.9 75.1 -7.3 36 0.2
6250 19.8 67.6 200 9 5 1.5 0.8 23.3 73.9 -8.0 26 0.1
6000 19.8 67.6 200 9 5 -1.7 -0.9 22.6 72.6 -8.7 18 0.1
5750 19.4 66.9 200 7 4 -8.6 -4.7 21.4 70.6 -9.9 23 0.1
5500 18.9 66.0 200 5 3 0.3 0.2 20.2 68.4 -11.1 31 0.2
* * * * * * NUMERICAL WEATHER PREDICTION MODEL FORECAST DATA VALID * * * * * *
08/31/2026 AT 0900 MDT | 08/31/2026 AT 1200 MDT
|
CAPE... +0.6 LI... +1.1 | CAPE... +18.8 LI... +0.4
CINH... -3.5 K INDEX... +24.3 | CINH... -46.9 K INDEX... +24.3
|
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 -61.4 -78.5 235 45 23 1.2 0.6 | -62.8 -81.0 230 43 22 2.1 1.1
45000 -59.3 -74.7 240 61 31 2.1 1.2 | -59.3 -74.7 235 55 29 2.8 1.6
40000 -54.6 -66.3 245 60 31 8.3 4.5 | -53.7 -64.7 245 60 31 7.9 4.3
38000 -49.6 -57.3 240 55 28 8.3 4.5 | -49.0 -56.2 240 57 30 7.9 4.3
36000 -44.7 -48.5 235 51 26 8.3 4.5 | -44.3 -47.7 235 55 28 8.0 4.4
34000 -39.8 -39.6 230 48 25 8.1 4.4 | -39.2 -38.6 235 50 26 8.5 4.7
32000 -35.0 -31.0 230 46 24 8.1 4.4 | -34.1 -29.4 230 45 23 8.6 4.7
30000 -30.2 -22.4 230 41 21 8.1 4.4 | -29.4 -20.9 225 41 21 7.7 4.3
29000 -27.8 -18.0 230 39 20 8.1 4.4 | -27.2 -17.0 220 40 20 7.8 4.3
28000 -25.5 -13.9 235 36 19 6.8 3.8 | -24.9 -12.8 215 38 20 7.2 3.9
27000 -23.6 -10.5 235 33 17 6.1 3.3 | -22.8 -9.0 215 33 17 6.9 3.8
26000 -21.8 -7.2 235 30 15 6.1 3.3 | -20.3 -4.5 215 28 14 6.9 3.8
25000 -19.6 -3.3 240 26 13 7.4 4.1 | -18.3 -0.9 215 23 12 6.1 3.3
24000 -17.0 1.4 235 25 13 8.4 4.6 | -16.7 1.9 215 21 11 5.5 3.0
23000 -14.4 6.1 230 24 13 8.4 4.6 | -15.0 5.0 215 20 10 5.5 3.0
22000 -12.0 10.4 230 24 12 6.8 3.7 | -13.3 8.1 215 19 10 7.1 3.9
21000 -10.1 13.8 225 23 12 6.2 3.4 | -11.0 12.2 220 20 10 7.7 4.2
20000 -8.3 17.1 225 21 11 6.3 3.4 | -8.7 16.3 225 20 11 7.7 4.2
19500 -7.4 18.7 225 21 11 6.2 3.4 | -7.5 18.5 225 21 11 7.6 4.2
19000 -6.6 20.1 225 20 10 5.6 3.1 | -6.4 20.5 225 21 11 7.2 4.0
18500 -5.9 21.4 225 20 10 5.7 3.1 | -5.3 22.5 225 21 11 7.3 4.0
18000 -5.0 23.0 230 19 10 6.6 3.6 | -4.3 24.3 225 20 10 5.8 3.2
17500 -4.1 24.6 230 19 10 6.8 3.7 | -3.5 25.7 225 18 9 5.5 3.0
17000 -3.1 26.4 235 18 9 6.9 3.8 | -2.7 27.1 225 16 8 5.6 3.1
16500 -2.1 28.2 235 16 8 7.1 3.9 | -1.9 28.6 225 14 7 6.1 3.4
16000 -1.0 30.2 235 14 7 7.1 3.9 | -1.1 30.0 225 12 6 6.0 3.3
15500 0.0 32.0 240 12 6 7.5 4.1 | -0.1 31.8 220 10 5 7.8 4.3
15000 1.1 34.0 245 10 5 7.5 4.1 | 1.0 33.8 215 9 5 7.8 4.3
14500 2.2 36.0 250 7 4 8.0 4.4 | 2.1 35.8 205 8 4 8.7 4.8
14000 3.4 38.1 260 6 3 8.2 4.5 | 3.5 38.3 195 8 4 9.1 5.0
13500 4.6 40.3 275 4 2 8.3 4.6 | 4.8 40.6 180 7 4 9.0 4.9
13000 5.9 42.6 290 4 2 8.6 4.7 | 6.1 43.0 175 7 3 8.8 4.8
12500 7.2 45.0 305 5 2 8.6 4.7 | 7.4 45.3 165 6 3 8.8 4.8
12000 8.4 47.1 315 5 3 8.7 4.8 | 8.7 47.7 155 5 3 8.7 4.8
11500 9.7 49.5 325 6 3 8.7 4.8 | 10.0 50.0 150 4 2 8.7 4.7
11000 11.0 51.8 330 6 3 8.6 4.7 | 11.3 52.3 140 2 1 8.5 4.7
10500 12.3 54.1 335 6 3 7.4 4.1 | 12.6 54.7 115 1 1 7.3 4.0
10250 12.8 55.0 340 6 3 7.7 4.2 | 13.1 55.6 095 1 1 7.6 4.1
10000 13.5 56.3 345 6 3 9.5 5.2 | 13.7 56.7 070 1 1 9.3 5.1
9750 14.1 57.4 350 6 3 9.1 5.0 | 14.4 57.9 050 1 1 8.9 4.9
9500 14.8 58.6 355 5 3 8.9 4.9 | 15.0 59.0 040 1 1 8.7 4.8
9250 15.4 59.7 360 5 3 7.7 4.2 | 15.7 60.3 040 2 1 7.9 4.3
9000 16.0 60.8 360 5 2 7.8 4.3 | 16.2 61.2 045 2 1 8.2 4.5
8750 16.6 61.9 360 4 2 8.7 4.7 | 17.5 63.5 040 2 1 8.1 4.4
8500 17.7 63.9 345 3 1 5.7 3.1 | 18.0 64.4 040 2 1 5.9 3.2
8250 18.0 64.4 330 2 1 5.1 2.8 | 18.5 65.3 035 2 1 7.0 3.8
8000 18.4 65.1 300 2 1 5.9 3.2 | 19.1 66.4 025 1 1 9.2 5.0
7750 18.8 65.8 275 3 1 4.2 2.3 | 19.7 67.5 005 1 1 8.4 4.6
7500 19.0 66.2 265 3 2 2.1 1.1 | 20.3 68.5 355 1 1 7.5 4.1
7250 19.2 66.6 260 4 2 2.1 1.2 | 20.8 69.4 355 1 1 8.1 4.4
7000 19.3 66.7 255 4 2 2.0 1.1 | 21.5 70.7 350 1 1 9.9 5.4
6750 19.5 67.1 250 5 2 3.8 2.1 | 22.3 72.1 340 2 1 10.2 5.6
6500 19.9 67.8 250 5 2 5.5 3.0 | 23.0 73.4 340 2 1 9.9 5.4
6250 20.2 68.4 250 4 2 4.4 2.4 | 23.7 74.7 340 2 1 9.3 5.1
6000 20.6 69.1 245 4 2 7.0 3.9 | 24.5 76.1 340 2 1 12.8 7.0
5750 21.3 70.3 245 4 2 13.8 7.6 | 25.8 78.4 340 2 1 22.1 12.1
5500 22.3 72.1 245 3 2 8.6 4.7 | 27.3 81.1 340 2 1 12.4 6.8
08/31/2026 AT 1500 MDT | 08/31/2026 AT 1800 MDT
|
CAPE... +60.0 LI... -1.7 | CAPE... +7.1 LI... -1.0
CINH... -21.1 K INDEX... +26.5 | CINH... -62.2 K INDEX... +29.2
|
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 -63.0 -81.4 230 42 21 2.4 1.3 | -63.0 -81.4 235 41 21 1.7 0.9
45000 -59.2 -74.6 230 51 26 2.8 1.5 | -59.4 -74.9 230 54 28 3.5 1.9
40000 -53.6 -64.5 235 61 32 8.2 4.5 | -53.0 -63.4 220 61 31 8.5 4.6
38000 -48.7 -55.7 230 53 27 8.1 4.5 | -47.9 -54.2 225 57 29 8.4 4.6
36000 -43.8 -46.8 225 44 23 8.3 4.6 | -42.8 -45.0 225 54 28 8.5 4.7
34000 -38.6 -37.5 225 41 21 8.8 4.8 | -37.7 -35.9 225 51 26 8.7 4.7
32000 -33.4 -28.1 225 39 20 8.9 4.9 | -32.5 -26.5 220 49 25 8.9 4.9
30000 -28.8 -19.8 225 37 19 7.6 4.2 | -28.1 -18.6 225 43 22 7.2 3.9
29000 -26.5 -15.7 225 36 18 7.6 4.2 | -26.0 -14.8 225 39 20 7.2 3.9
28000 -24.3 -11.7 220 35 18 7.0 3.8 | -23.9 -11.0 225 36 19 7.1 3.9
27000 -22.3 -8.1 220 37 19 6.7 3.7 | -21.2 -6.2 225 37 19 7.1 3.9
26000 -19.9 -3.8 215 40 20 6.7 3.7 | -19.2 -2.6 225 38 19 7.1 3.9
25000 -17.9 -0.2 215 42 21 6.4 3.5 | -17.1 1.2 225 39 20 6.7 3.7
24000 -16.1 3.0 210 39 20 6.2 3.4 | -15.2 4.6 225 39 20 6.3 3.4
23000 -14.2 6.4 205 37 19 6.3 3.4 | -13.3 8.1 225 39 20 6.3 3.4
22000 -12.4 9.7 200 34 18 5.4 3.0 | -11.5 11.3 225 39 20 5.8 3.2
21000 -10.9 12.4 205 27 14 5.0 2.8 | -9.9 14.2 225 37 19 5.5 3.0
20000 -9.4 15.1 215 19 10 5.1 2.8 | -8.3 17.1 225 34 18 5.5 3.0
19500 -8.7 16.3 225 16 8 5.6 3.1 | -7.5 18.5 225 33 17 5.6 3.1
19000 -7.5 18.5 225 15 8 8.8 4.8 | -6.6 20.1 220 31 16 6.8 3.7
18500 -6.3 20.7 230 14 7 8.7 4.7 | -5.6 21.9 215 28 14 6.7 3.7
18000 -5.0 23.0 230 13 7 8.0 4.4 | -4.7 23.5 210 25 13 6.8 3.7
17500 -3.8 25.2 230 13 7 7.9 4.3 | -3.7 25.3 210 23 12 6.8 3.7
17000 -2.7 27.1 230 13 7 7.8 4.3 | -2.7 27.1 210 22 11 6.8 3.8
16500 -1.6 29.1 230 13 7 7.6 4.2 | -1.7 28.9 205 21 11 7.1 3.9
16000 -0.5 31.1 230 13 7 7.6 4.2 | -0.7 30.7 205 20 10 7.1 3.9
15500 0.7 33.3 230 13 7 8.1 4.5 | 0.4 32.7 205 19 10 7.6 4.1
15000 1.8 35.2 225 13 7 8.2 4.5 | 1.5 34.7 200 17 9 7.6 4.2
14500 3.0 37.4 225 12 6 7.7 4.2 | 2.6 36.7 195 15 8 8.0 4.4
14000 4.1 39.4 215 11 6 7.5 4.1 | 3.8 38.8 190 14 7 8.3 4.6
13500 5.1 41.2 205 9 5 7.9 4.3 | 5.0 41.0 180 13 7 8.3 4.6
13000 6.4 43.5 190 8 4 8.6 4.7 | 6.2 43.2 175 12 6 8.3 4.5
12500 7.6 45.7 175 7 4 8.8 4.8 | 7.4 45.3 170 11 6 8.3 4.5
12000 9.0 48.2 165 7 4 9.6 5.2 | 8.6 47.5 165 10 5 8.2 4.5
11500 10.4 50.7 160 7 4 9.5 5.2 | 9.9 49.8 160 8 4 8.2 4.5
11000 11.8 53.2 150 7 4 9.2 5.0 | 11.1 52.0 155 7 3 8.1 4.5
10500 13.2 55.8 150 7 4 9.9 5.4 | 12.3 54.1 145 5 2 7.6 4.2
10250 13.9 57.0 145 7 4 10.2 5.6 | 12.8 55.0 140 4 2 7.5 4.1
10000 14.7 58.5 140 7 4 9.5 5.2 | 13.4 56.1 130 3 1 8.1 4.5
9750 15.4 59.7 140 7 4 9.8 5.4 | 14.0 57.2 110 2 1 7.9 4.4
9500 16.1 61.0 135 7 4 9.3 5.1 | 14.6 58.3 070 2 1 8.0 4.4
9250 16.8 62.2 135 7 4 8.8 4.8 | 15.2 59.4 030 2 1 7.1 3.9
9000 17.5 63.5 130 7 4 9.6 5.3 | 15.7 60.3 005 3 2 6.6 3.6
8750 19.0 66.2 125 7 4 9.8 5.4 | 16.7 62.1 345 6 3 6.9 3.8
8500 19.6 67.3 125 7 4 7.9 4.3 | 17.2 63.0 345 7 4 6.6 3.6
8250 20.2 68.4 120 7 4 9.1 5.0 | 17.7 63.9 340 8 4 6.5 3.6
8000 21.0 69.8 120 8 4 11.5 6.3 | 18.2 64.8 335 9 5 6.8 3.7
7750 21.9 71.4 115 8 4 10.2 5.6 | 18.7 65.7 335 10 5 6.5 3.6
7500 22.6 72.7 115 8 4 8.9 4.9 | 19.1 66.4 330 11 6 5.8 3.2
7250 23.2 73.8 110 8 4 9.2 5.1 | 19.5 67.1 325 12 6 5.8 3.2
7000 24.0 75.2 110 8 4 10.8 5.9 | 20.0 68.0 325 13 7 7.0 3.9
6750 24.8 76.6 105 8 4 10.9 6.0 | 20.5 68.9 320 13 7 6.7 3.7
6500 25.6 78.1 105 8 4 10.4 5.7 | 20.9 69.6 315 13 7 5.8 3.2
6250 26.4 79.5 100 8 4 10.0 5.5 | 21.3 70.3 310 13 7 5.8 3.2
6000 27.1 80.8 100 8 4 11.7 6.4 | 21.8 71.2 310 14 7 7.1 3.9
5750 28.2 82.8 095 8 4 18.9 10.3 | 22.4 72.3 305 12 6 10.7 5.9
5500 29.9 85.8 095 7 3 24.1 13.2 | 23.1 73.6 305 9 5 8.2 4.5
________________________________________________________________________________
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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