739
UXUS97 KBOU 111227
SRGBOU
SOARING FORECAST
NATIONAL WEATHER SERVICE DENVER/BOULDER, COLORADO
0626 MDT THURSDAY, JUNE 11, 2026
THIS FORECAST IS FOR THURSDAY, JUNE 11, 2026:
IF THE TRIGGER TEMPERATURE OF 64.2 F/17.9 C IS REACHED...THEN
THERMAL SOARING INDEX....................... GOOD
MAXIMUM RATE OF LIFT........................ 773 FT/MIN (3.9 M/S)
MAXIMUM HEIGHT OF THERMALS.................. 15415 FT MSL (10058 FT AGL)
FORECAST MAXIMUM TEMPERATURE................... 79.0 F/26.6 C
TIME OF TRIGGER TEMPERATURE.................... 0930 MDT
TIME OF OVERDEVELOPMENT........................ NONE
MIDDLE/HIGH CLOUDS DURING SOARING WINDOW....... NONE
SURFACE WINDS DURING SOARING WINDOW............ 20 MPH OR LESS
HEIGHT OF THE -3 THERMAL INDEX................. 13171 FT MSL (7814 FT AGL)
THERMAL SOARING OUTLOOK FOR FRIDAY 06/12....... GOOD
WAVE SOARING INDEX............................. FAIR
WAVE SOARING INDEX TREND (TO 1800 MDT)......... SLIGHT DECREASE
HEIGHT OF STABLE LAYER (12-18K FT MSL)......... NONE
WEAK PVA/NVA (THROUGH 1800 MDT)................ NEITHER
POTENTIAL HEIGHT OF WAVE....................... 45954 FT MSL (40597 FT AGL)
WAVE SOARING OUTLOOK FOR FRIDAY 06/12.......... POOR
REMARKS...
SUNRISE/SUNSET.................... 05:30:53 / 20:27:33 MDT
TOTAL POSSIBLE SUNSHINE........... 14 HR 56 MIN 40 SEC (896 MIN 40 SEC)
ALTITUDE OF SUN AT 12:59:13 MDT... 73.36 DEGREES
UPPER AIR DATA FROM NUMERICAL MODEL FORECAST VALID ON 06/11/2026 AT 0600 MDT
FREEZING LEVEL.................. 12765 FT MSL (7408 FT AGL)
CONVECTIVE CONDENSATION LEVEL... 21699 FT MSL (16342 FT AGL)
LIFTED CONDENSATION LEVEL....... 18142 FT MSL (12785 FT AGL)
LIFTED INDEX.................... +6.8
K INDEX......................... +4.8
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 -59.3 -74.7 255 58 30 0.2 0.1 M M M M M
45000 -58.6 -73.5 260 81 42 1.8 1.0 M M M M M
40000 -55.8 -68.4 255 75 38 4.0 2.2 M M M M M
38000 -52.0 -61.6 260 75 38 6.3 3.5 M M M M M
36000 -48.2 -54.8 270 76 39 6.3 3.5 M M M M M
34000 -42.9 -45.2 270 76 39 8.7 4.8 M M M M M
32000 -37.7 -35.9 265 77 40 8.7 4.8 M M M M M
30000 -32.4 -26.3 265 77 40 8.9 4.9 44.0 111.2 13.6 M M
29000 -29.8 -21.6 265 77 39 8.9 4.9 43.7 110.6 13.5 M M
28000 -27.1 -16.8 265 76 39 9.0 4.9 43.4 110.2 13.5 M M
27000 -24.7 -12.5 265 76 39 7.5 4.1 42.7 108.9 13.0 M M
26000 -22.5 -8.5 265 76 39 7.4 4.1 41.8 107.2 12.5 M M
25000 -20.3 -4.5 265 76 39 7.4 4.1 41.0 105.8 11.9 M M
24000 -18.2 -0.8 265 76 39 6.2 3.4 40.0 104.0 11.3 M M
23000 -16.3 2.7 265 76 39 6.3 3.4 38.7 101.6 10.3 M M
22000 -14.4 6.1 270 75 39 6.3 3.4 37.5 99.4 9.4 M M
21000 -12.7 9.1 270 74 38 5.0 2.8 36.0 96.9 8.3 M M
20000 -11.3 11.7 270 73 37 5.1 2.8 34.3 93.8 6.9 M M
19500 -10.2 13.6 270 72 37 5.1 2.8 33.1 91.6 5.9 M M
19000 -9.4 15.1 270 71 36 5.0 2.7 32.4 90.3 5.2 M M
18500 -8.7 16.3 270 69 36 4.8 2.6 31.5 88.7 4.5 M M
18000 -8.0 17.6 270 68 35 4.8 2.7 30.7 87.2 3.7 M M
17500 -7.3 18.9 270 66 34 5.0 2.8 29.8 85.7 3.0 M M
17000 -6.6 20.1 270 63 33 5.0 2.8 29.0 84.2 2.2 M M
16500 -5.9 21.4 270 61 31 5.0 2.7 28.2 82.8 1.5 M M
16000 -5.2 22.6 270 56 29 4.9 2.7 27.4 81.3 0.8 M M
15500 -4.5 23.9 270 52 27 5.0 2.7 26.6 79.9 0.0 M M
15000 -3.7 25.3 270 47 24 5.4 3.0 25.9 78.5 -0.7 738 3.7
14500 -2.9 26.8 270 43 22 5.3 2.9 25.1 77.2 -1.3 700 3.6
14000 -2.1 28.2 270 38 20 5.8 3.2 24.4 76.0 -2.0 660 3.4
13500 -1.2 29.8 270 34 18 5.7 3.1 23.8 74.8 -2.6 620 3.2
13000 -0.4 31.3 270 31 16 5.9 3.2 23.1 73.6 -3.2 580 2.9
12500 0.5 32.9 270 28 14 5.9 3.2 22.5 72.5 -3.8 539 2.7
12000 1.4 34.5 275 26 13 5.6 3.1 21.9 71.4 -4.4 498 2.5
11500 2.2 36.0 280 25 13 5.6 3.1 21.2 70.1 -5.1 458 2.3
11000 3.0 37.4 285 25 13 5.2 2.8 20.5 68.9 -5.8 419 2.1
10500 3.8 38.8 290 26 13 4.6 2.5 19.8 67.6 -6.5 381 1.9
10250 4.2 39.6 290 26 13 6.7 3.7 19.4 66.9 -6.8 362 1.8
10000 4.8 40.6 295 27 14 7.1 3.9 19.2 66.6 -7.0 337 1.7
9750 5.2 41.4 295 27 14 5.4 3.0 18.9 66.1 -7.3 316 1.6
9500 5.6 42.1 295 27 14 5.8 3.2 18.6 65.5 -7.6 296 1.5
9250 6.1 43.0 295 27 14 6.0 3.3 18.3 64.9 -7.9 275 1.4
9000 6.5 43.7 295 27 14 6.5 3.6 18.0 64.5 -8.2 254 1.3
8750 7.0 44.6 295 26 13 6.7 3.7 17.8 64.0 -8.5 232 1.2
8500 7.5 45.5 295 24 12 6.5 3.6 17.6 63.6 -8.7 210 1.1
8250 8.0 46.4 295 23 12 7.1 3.9 17.3 63.2 -9.0 188 1.0
8000 8.5 47.3 300 22 11 7.2 4.0 17.1 62.8 -9.2 164 0.8
7750 9.0 48.2 300 20 10 5.7 3.1 16.9 62.4 -9.5 142 0.7
7500 9.4 48.9 305 18 9 5.0 2.7 16.5 61.7 -9.9 124 0.6
7250 9.7 49.5 310 16 8 4.2 2.3 16.1 61.1 -10.3 107 0.5
7000 10.0 50.0 315 15 8 3.4 1.8 15.7 60.2 -10.8 91 0.5
6750 10.3 50.5 320 13 7 4.7 2.6 15.2 59.4 -11.3 76 0.4
6500 10.6 51.1 330 12 6 4.5 2.4 14.9 58.8 -11.7 58 0.3
6250 10.8 51.4 335 10 5 3.1 1.7 14.4 57.9 -12.2 44 0.2
6000 11.0 51.8 345 8 4 2.8 1.6 13.9 57.0 -12.8 30 0.2
5750 11.3 52.3 355 6 3 4.4 2.4 13.4 56.1 -13.3 16 0.1
5500 11.6 52.9 355 4 2 5.1 2.8 13.1 55.5 -13.7 M M
* * * * * * NUMERICAL WEATHER PREDICTION MODEL FORECAST DATA VALID * * * * * *
06/11/2026 AT 0900 MDT | 06/11/2026 AT 1200 MDT
|
CAPE... 0.0 LI... +9.7 | CAPE... 0.0 LI... +9.4
CINH... -0.3 K INDEX... -29.0 | CINH... -0.4 K INDEX... -19.8
|
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 -60.1 -76.2 265 51 26 0.5 0.3 | -60.3 -76.5 265 47 24 0.4 0.2
45000 -58.9 -74.0 265 74 38 1.8 1.0 | -59.2 -74.6 265 67 35 2.0 1.1
40000 -56.2 -69.2 255 70 36 4.4 2.4 | -56.1 -69.0 260 68 35 4.8 2.7
38000 -52.2 -62.0 265 69 36 6.7 3.7 | -52.0 -61.6 265 63 32 6.8 3.7
36000 -48.2 -54.8 270 70 36 6.7 3.7 | -47.9 -54.2 270 59 30 6.8 3.7
34000 -42.7 -44.9 270 70 36 8.8 4.8 | -42.6 -44.7 270 59 30 8.4 4.6
32000 -37.4 -35.3 270 69 36 8.8 4.9 | -37.6 -35.7 270 60 31 8.4 4.6
30000 -32.2 -26.0 265 69 36 8.5 4.7 | -32.5 -26.5 265 62 32 8.4 4.6
29000 -29.7 -21.5 265 69 36 8.5 4.7 | -30.0 -22.0 270 63 32 8.4 4.6
28000 -27.1 -16.8 265 69 36 8.6 4.7 | -27.5 -17.5 270 64 33 8.5 4.6
27000 -24.8 -12.6 265 70 36 7.4 4.0 | -25.1 -13.2 270 65 33 7.7 4.2
26000 -22.6 -8.7 270 71 36 7.4 4.0 | -22.8 -9.0 275 66 34 7.7 4.2
25000 -20.4 -4.7 270 72 37 7.4 4.0 | -20.5 -4.9 275 68 35 7.7 4.2
24000 -18.3 -0.9 270 72 37 6.2 3.4 | -18.3 -0.9 280 68 35 6.8 3.8
23000 -16.5 2.3 270 72 37 6.2 3.4 | -16.3 2.7 280 68 35 6.8 3.8
22000 -14.6 5.7 275 71 37 6.2 3.4 | -14.2 6.4 280 67 35 6.8 3.7
21000 -12.9 8.8 275 70 36 4.9 2.7 | -12.5 9.5 280 65 34 4.8 2.7
20000 -11.4 11.5 275 67 34 4.9 2.7 | -11.0 12.2 275 62 32 4.8 2.6
19500 -10.3 13.5 275 64 33 4.9 2.7 | -10.0 14.0 275 60 31 4.8 2.6
19000 -9.6 14.7 275 62 32 4.5 2.4 | -9.3 15.3 275 58 30 3.1 1.7
18500 -9.0 15.8 275 60 31 4.1 2.3 | -9.0 15.8 270 54 28 2.3 1.3
18000 -8.4 16.9 275 57 29 4.1 2.2 | -8.6 16.5 270 50 26 2.3 1.3
17500 -7.7 18.1 280 54 28 4.1 2.3 | -8.2 17.2 270 45 23 3.6 2.0
17000 -7.1 19.2 280 51 26 4.1 2.3 | -7.7 18.1 270 41 21 3.5 1.9
16500 -6.5 20.3 280 48 24 4.3 2.4 | -7.1 19.2 270 37 19 4.5 2.5
16000 -5.8 21.6 285 44 23 4.5 2.5 | -6.4 20.5 275 34 17 4.8 2.7
15500 -5.2 22.6 290 41 21 4.7 2.6 | -5.7 21.7 275 30 15 5.5 3.0
15000 -4.4 24.1 290 38 19 5.6 3.1 | -4.7 23.5 280 27 14 6.6 3.6
14500 -3.5 25.7 295 35 18 5.5 3.0 | -3.8 25.2 285 25 13 6.7 3.7
14000 -2.6 27.3 300 33 17 6.4 3.5 | -2.7 27.1 285 24 12 7.9 4.3
13500 -1.7 28.9 300 30 16 6.3 3.5 | -1.5 29.3 290 23 12 7.9 4.3
13000 -0.7 30.7 305 28 15 6.9 3.8 | -0.4 31.3 295 22 11 7.2 3.9
12500 0.3 32.5 305 27 14 6.9 3.8 | 0.7 33.3 295 20 10 7.2 3.9
12000 1.3 34.3 305 25 13 6.8 3.7 | 1.8 35.2 300 19 10 7.8 4.3
11500 2.3 36.1 305 24 12 6.8 3.7 | 3.0 37.4 300 17 9 7.9 4.3
11000 3.3 37.9 305 23 12 6.0 3.3 | 4.1 39.4 305 16 8 7.5 4.1
10500 4.1 39.4 305 22 11 6.5 3.6 | 5.2 41.4 310 14 7 8.1 4.5
10250 4.5 40.1 305 22 11 3.2 1.7 | 5.8 42.4 310 13 7 5.1 2.8
10000 4.7 40.5 305 22 11 3.9 2.1 | 6.1 43.0 310 12 6 6.4 3.5
9750 5.2 41.4 305 21 11 7.6 4.2 | 6.8 44.2 315 12 6 10.1 5.5
9500 5.7 42.3 305 20 10 7.3 4.0 | 7.5 45.5 320 11 6 9.9 5.4
9250 6.2 43.2 305 19 10 4.9 2.7 | 8.2 46.8 325 10 5 7.0 3.8
9000 6.4 43.5 305 18 9 4.6 2.6 | 8.6 47.5 330 9 5 6.8 3.7
8750 6.9 44.4 305 17 9 7.6 4.1 | 9.2 48.6 335 9 4 9.9 5.4
8500 7.4 45.3 305 16 8 7.3 4.0 | 9.9 49.8 345 8 4 9.1 5.0
8250 7.9 46.2 305 15 7 6.5 3.6 | 10.6 51.1 350 8 4 8.4 4.6
8000 8.3 46.9 305 13 7 6.3 3.5 | 11.2 52.2 355 8 4 8.6 4.7
7750 8.9 48.0 305 12 6 8.2 4.5 | 11.9 53.4 360 8 4 10.8 5.9
7500 9.5 49.1 310 10 5 8.7 4.8 | 12.7 54.9 005 8 4 10.3 5.7
7250 10.1 50.2 315 9 5 8.3 4.6 | 13.4 56.1 005 9 4 8.3 4.5
7000 10.7 51.3 315 9 4 8.1 4.5 | 14.0 57.2 010 9 4 8.0 4.4
6750 11.4 52.5 320 8 4 11.2 6.1 | 14.7 58.5 015 9 5 12.2 6.7
6500 12.3 54.1 320 8 4 11.7 6.4 | 15.7 60.3 015 9 5 12.4 6.8
6250 13.1 55.6 325 7 4 9.9 5.4 | 16.5 61.7 015 9 5 10.1 5.5
6000 13.8 56.8 325 7 3 9.6 5.3 | 17.3 63.1 020 9 5 9.5 5.2
5750 14.6 58.3 325 6 3 12.5 6.8 | 18.1 64.6 025 9 5 14.4 7.9
5500 15.8 60.4 330 6 3 21.8 12.0 | 19.7 67.5 025 9 4 29.7 16.3
06/11/2026 AT 1500 MDT | 06/11/2026 AT 1800 MDT
|
CAPE... 0.0 LI... +6.6 | CAPE... 0.0 LI... +5.8
CINH... -0.1 K INDEX... -7.7 | CINH... -0.3 K INDEX... +2.9
|
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 -76.7 265 43 22 1.3 0.7 | -60.8 -77.4 270 42 22 2.0 1.1
45000 -58.2 -72.8 270 63 32 2.1 1.2 | -57.8 -72.0 275 60 31 2.1 1.1
40000 -55.0 -67.0 265 74 38 4.4 2.4 | -54.7 -66.5 275 76 39 4.3 2.4
38000 -51.4 -60.5 265 68 35 5.9 3.3 | -50.6 -59.1 275 73 38 5.9 3.3
36000 -47.4 -53.3 265 61 31 6.0 3.3 | -47.1 -52.8 270 70 36 5.9 3.3
34000 -43.1 -45.6 265 60 31 7.8 4.3 | -43.3 -45.9 275 65 34 6.5 3.5
32000 -38.4 -37.1 270 61 32 7.8 4.3 | -39.4 -38.9 275 60 31 6.5 3.6
30000 -33.7 -28.7 275 61 32 7.9 4.3 | -35.0 -31.0 280 57 29 7.8 4.3
29000 -31.4 -24.5 280 61 32 7.9 4.3 | -32.7 -26.9 285 56 29 7.8 4.3
28000 -29.0 -20.2 280 62 32 7.8 4.3 | -30.3 -22.5 285 55 29 7.7 4.2
27000 -26.6 -15.9 280 61 31 8.2 4.5 | -27.8 -18.0 285 54 28 8.6 4.7
26000 -24.1 -11.4 285 60 31 8.2 4.5 | -25.2 -13.4 290 53 27 8.6 4.7
25000 -21.6 -6.9 285 60 31 8.1 4.5 | -22.6 -8.7 290 51 26 8.5 4.7
24000 -19.4 -2.9 285 59 30 6.7 3.7 | -20.3 -4.5 290 50 26 7.4 4.1
23000 -17.4 0.7 285 57 30 6.6 3.6 | -18.0 -0.4 285 48 25 7.4 4.0
22000 -15.4 4.3 280 56 29 6.6 3.6 | -15.8 3.6 280 47 24 7.4 4.1
21000 -13.7 7.3 275 54 28 5.3 2.9 | -13.4 7.9 275 45 23 6.3 3.5
20000 -11.7 10.9 270 51 26 5.3 2.9 | -11.5 11.3 265 43 22 6.4 3.5
19500 -11.0 12.2 265 49 25 5.3 2.9 | -10.5 13.1 265 42 22 6.4 3.5
19000 -10.2 13.6 265 48 25 5.4 2.9 | -9.6 14.7 260 41 21 6.6 3.6
18500 -9.4 15.1 265 45 23 5.4 3.0 | -8.6 16.5 255 40 21 6.7 3.7
18000 -8.6 16.5 260 43 22 5.4 3.0 | -7.6 18.3 255 39 20 6.9 3.8
17500 -7.8 18.0 260 40 21 5.5 3.0 | -6.6 20.1 255 37 19 7.3 4.0
17000 -7.0 19.4 260 38 19 5.4 3.0 | -5.5 22.1 250 35 18 7.4 4.1
16500 -6.1 21.0 260 35 18 6.8 3.7 | -4.5 23.9 250 32 17 7.2 3.9
16000 -5.1 22.8 260 33 17 6.9 3.8 | -3.4 25.9 250 29 15 7.2 3.9
15500 -4.0 24.8 260 30 16 7.2 3.9 | -2.3 27.9 250 26 13 6.6 3.6
15000 -2.9 26.8 265 27 14 7.4 4.1 | -1.4 29.5 250 23 12 6.2 3.4
14500 -1.8 28.8 265 25 13 7.4 4.1 | -0.5 31.1 250 21 11 6.3 3.4
14000 -0.7 30.7 265 22 11 7.3 4.0 | 0.4 32.7 245 18 9 6.7 3.7
13500 0.3 32.5 270 18 9 7.3 4.0 | 1.4 34.5 245 15 8 6.7 3.7
13000 1.5 34.7 270 15 8 8.0 4.4 | 2.5 36.5 240 12 6 6.9 3.8
12500 2.7 36.9 270 13 6 7.9 4.3 | 3.5 38.3 230 9 5 6.8 3.8
12000 3.9 39.0 275 10 5 8.4 4.6 | 4.5 40.1 215 7 3 7.1 3.9
11500 5.1 41.2 280 8 4 8.4 4.6 | 5.6 42.1 185 5 2 6.9 3.8
11000 6.3 43.3 290 6 3 8.0 4.4 | 6.8 44.2 155 5 2 8.8 4.8
10500 7.5 45.5 315 4 2 8.7 4.8 | 8.0 46.4 140 5 3 9.2 5.0
10250 8.1 46.6 340 3 2 5.3 2.9 | 8.7 47.7 135 5 3 6.5 3.6
10000 8.4 47.1 355 3 2 6.2 3.4 | 9.1 48.4 135 5 3 7.9 4.3
9750 9.1 48.4 020 3 2 10.1 5.5 | 9.9 49.8 130 6 3 11.3 6.2
9500 9.8 49.6 035 4 2 9.4 5.2 | 10.7 51.3 125 6 3 10.7 5.9
9250 10.4 50.7 045 5 3 7.7 4.3 | 11.5 52.7 120 6 3 9.0 4.9
9000 11.0 51.8 050 6 3 8.6 4.7 | 12.1 53.8 120 7 3 8.9 4.9
8750 11.8 53.2 050 6 3 11.1 6.1 | 12.9 55.2 115 7 4 10.6 5.8
8500 12.6 54.7 055 7 3 10.4 5.7 | 13.6 56.5 115 7 4 10.1 5.5
8250 13.3 55.9 055 7 4 9.0 4.9 | 14.4 57.9 110 7 4 9.1 5.0
8000 13.9 57.0 055 7 4 9.0 4.9 | 15.0 59.0 110 8 4 9.1 5.0
7750 14.7 58.5 060 8 4 10.9 6.0 | 15.8 60.4 110 8 4 10.4 5.7
7500 15.5 59.9 060 8 4 10.3 5.6 | 16.5 61.7 110 8 4 9.9 5.5
7250 16.2 61.2 060 8 4 8.6 4.7 | 17.2 63.0 110 8 4 8.9 4.9
7000 16.8 62.2 060 9 4 8.6 4.7 | 17.9 64.2 105 8 4 8.9 4.9
6750 17.6 63.7 060 9 4 11.7 6.4 | 18.6 65.5 105 8 4 11.1 6.1
6500 18.5 65.3 060 9 5 11.9 6.5 | 19.5 67.1 105 8 4 11.2 6.1
6250 19.3 66.7 065 9 5 10.6 5.8 | 20.3 68.5 105 9 4 10.2 5.6
6000 20.1 68.2 065 9 5 9.9 5.4 | 21.1 70.0 105 9 4 10.0 5.5
5750 20.9 69.6 065 9 5 13.5 7.4 | 21.8 71.2 100 9 4 11.3 6.2
5500 22.4 72.3 065 9 4 27.3 15.0 | 22.9 73.2 100 8 4 18.0 9.9
________________________________________________________________________________
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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