446
UXUS97 KBOU 111317
SRGBOU
SOARING FORECAST
NATIONAL WEATHER SERVICE DENVER/BOULDER, COLORADO
0617 MST TUESDAY, NOVEMBER 11, 2025
THIS FORECAST IS FOR TUESDAY, NOVEMBER 11, 2025:
IF THE TRIGGER TEMPERATURE OF 70.6 F/21.4 C IS REACHED...THEN
THERMAL SOARING INDEX....................... POOR
MAXIMUM RATE OF LIFT........................ 152 FT/MIN (0.8 M/S)
MAXIMUM HEIGHT OF THERMALS.................. 9975 FT MSL (4676 FT AGL)
FORECAST MAXIMUM TEMPERATURE................... 71.0 F/22.1 C
TIME OF TRIGGER TEMPERATURE.................... 1245 MST
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................. 6929 FT MSL (1630 FT AGL)
THERMAL SOARING OUTLOOK FOR WEDNESDAY 11/12.... GOOD
WAVE SOARING INDEX............................. POOR
WAVE SOARING INDEX TREND (TO 1700 MST)......... NO CHANGE
HEIGHT OF STABLE LAYER (12-18K FT MSL)......... NONE
WEAK PVA/NVA (THROUGH 1700 MST)................ NEITHER
POTENTIAL HEIGHT OF WAVE....................... 39720 FT MSL (34421 FT AGL)
WAVE SOARING OUTLOOK FOR WEDNESDAY 11/12....... FAIR
REMARKS...
SUNRISE/SUNSET.................... 06:40:13 / 16:46:50 MST
TOTAL POSSIBLE SUNSHINE........... 10 HR 6 MIN 37 SEC (606 MIN 37 SEC)
ALTITUDE OF SUN AT 11:43:31 MST... 32.46 DEGREES
UPPER AIR DATA FROM NUMERICAL MODEL FORECAST VALID ON 11/11/2025 AT 0500 MST
FREEZING LEVEL.................. 13667 FT MSL (8368 FT AGL)
CONVECTIVE CONDENSATION LEVEL... 21550 FT MSL (16251 FT AGL)
LIFTED CONDENSATION LEVEL....... 18122 FT MSL (12823 FT AGL)
LIFTED INDEX.................... +6.0
K INDEX......................... +1.0
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 -66.7 -88.1 315 39 20 -1.1 -0.6 M M M M M
45000 -67.6 -89.7 305 58 30 3.8 2.1 M M M M M
40000 -61.7 -79.1 295 67 35 3.4 1.9 M M M M M
38000 -57.3 -71.1 295 65 33 7.8 4.3 M M M M M
36000 -52.6 -62.7 295 61 31 7.8 4.3 M M M M M
34000 -48.0 -54.4 295 57 29 7.6 4.2 M M M M M
32000 -43.4 -46.1 295 52 27 7.6 4.2 M M M M M
30000 -38.2 -36.8 295 48 25 7.9 4.4 37.0 98.6 11.6 M M
29000 -35.8 -32.4 295 47 24 8.0 4.4 36.3 97.4 11.2 M M
28000 -33.4 -28.1 295 46 24 8.0 4.4 35.7 96.3 10.8 M M
27000 -31.0 -23.8 300 45 23 8.0 4.4 35.0 95.0 10.4 M M
26000 -28.6 -19.5 300 44 23 8.0 4.4 34.3 93.7 10.0 M M
25000 -26.3 -15.3 300 43 22 8.0 4.4 33.7 92.7 9.6 M M
24000 -23.9 -11.0 305 42 22 7.9 4.3 33.1 91.5 9.2 M M
23000 -21.5 -6.7 305 41 21 7.9 4.3 32.3 90.2 8.7 M M
22000 -19.1 -2.4 305 40 20 7.9 4.3 31.7 89.1 8.3 M M
21000 -16.8 1.8 310 38 20 7.6 4.2 31.0 87.8 7.7 M M
20000 -14.6 5.7 310 37 19 7.6 4.2 30.2 86.4 7.2 M M
19500 -13.4 7.9 315 36 19 7.6 4.2 29.9 85.8 6.9 M M
19000 -12.3 9.9 315 36 18 7.6 4.2 29.6 85.2 6.7 M M
18500 -11.2 11.8 315 35 18 7.5 4.1 29.2 84.5 6.3 M M
18000 -10.1 13.8 315 35 18 7.5 4.1 28.8 83.8 6.0 M M
17500 -8.9 16.0 320 34 18 7.5 4.1 28.4 83.1 5.7 M M
17000 -7.8 18.0 320 34 18 7.5 4.1 28.0 82.4 5.4 M M
16500 -6.7 19.9 320 34 17 7.6 4.1 27.7 81.8 5.1 M M
16000 -5.6 21.9 320 34 17 7.6 4.2 27.3 81.1 4.8 M M
15500 -3.9 25.0 325 33 17 7.5 4.1 26.7 80.1 4.3 M M
15000 -2.8 27.0 325 33 17 7.5 4.1 26.4 79.5 4.0 M M
14500 -1.6 29.1 325 34 17 7.5 4.1 26.0 78.8 3.7 M M
14000 -0.5 31.1 325 33 17 7.4 4.1 25.6 78.1 3.4 M M
13500 0.6 33.1 325 33 17 7.4 4.1 25.2 77.4 3.0 M M
13000 1.7 35.1 320 33 17 7.3 4.0 24.9 76.7 2.7 M M
12500 2.8 37.0 320 33 17 7.4 4.0 24.5 76.1 2.3 M M
12000 3.8 38.8 320 33 17 7.2 3.9 24.1 75.3 2.0 M M
11500 4.9 40.8 315 33 17 7.2 4.0 23.7 74.6 1.6 M M
11000 6.0 42.8 315 33 17 6.9 3.8 23.2 73.8 1.2 M M
10500 7.0 44.6 310 32 17 7.2 4.0 22.8 73.0 0.7 M M
10250 7.5 45.5 310 32 17 3.9 2.1 22.5 72.5 0.5 M M
10000 7.7 45.9 310 32 16 5.8 3.2 22.0 71.6 -0.0 352 1.8
9750 8.4 47.1 310 31 16 9.8 5.4 21.9 71.5 -0.1 325 1.6
9500 9.0 48.2 310 31 16 9.0 4.9 21.9 71.4 -0.1 297 1.5
9250 9.6 49.3 305 30 16 5.0 2.8 21.8 71.2 -0.3 272 1.4
9000 9.9 49.8 305 31 16 5.1 2.8 21.3 70.3 -0.7 257 1.3
8750 10.5 50.9 305 31 16 8.8 4.8 21.1 70.0 -0.9 232 1.2
8500 11.0 51.8 300 31 16 7.3 4.0 21.0 69.8 -1.0 207 1.1
8250 11.5 52.7 300 31 16 4.9 2.7 20.7 69.3 -1.3 186 0.9
8000 11.8 53.2 300 33 17 4.8 2.6 20.3 68.5 -1.7 169 0.9
7750 12.3 54.1 295 32 17 8.6 4.7 20.1 68.1 -2.0 147 0.7
7500 13.0 55.4 295 31 16 7.2 3.9 20.0 68.0 -2.0 120 0.6
7250 13.3 55.9 295 30 16 3.6 2.0 19.6 67.3 -2.4 102 0.5
7000 13.6 56.5 290 30 16 3.7 2.0 19.1 66.5 -2.9 86 0.4
6750 14.0 57.2 290 29 15 7.6 4.2 18.8 65.8 -3.2 67 0.3
6500 14.6 58.3 290 24 12 5.6 3.1 18.7 65.6 -3.3 41 0.2
6250 14.7 58.5 285 21 11 0.3 0.2 18.1 64.5 -4.0 30 0.2
6000 14.9 58.8 285 19 10 4.2 2.3 17.5 63.5 -4.6 18 0.1
5750 15.0 59.0 280 16 8 -4.9 -2.7 16.9 62.4 -5.1 6 0.0
5500 13.7 56.7 270 11 6 -30.2 -16.6 14.9 58.8 -7.2 38 0.2
* * * * * * NUMERICAL WEATHER PREDICTION MODEL FORECAST DATA VALID * * * * * *
11/11/2025 AT 0800 MST | 11/11/2025 AT 1100 MST
|
CAPE... 0.0 LI... +4.5 | CAPE... 0.0 LI... +4.6
CINH... -0.0 K INDEX... +5.6 | CINH... -0.3 K INDEX... +5.9
|
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 -66.8 -88.2 305 36 18 -0.7 -0.4 | -66.4 -87.5 290 34 18 -0.7 -0.4
45000 -67.2 -89.0 300 64 33 3.6 2.0 | -66.9 -88.4 290 64 33 3.4 1.8
40000 -61.5 -78.7 290 64 33 3.4 1.9 | -61.8 -79.2 285 62 32 3.1 1.7
38000 -57.2 -71.0 290 62 32 7.8 4.3 | -57.5 -71.5 290 59 30 7.8 4.3
36000 -52.6 -62.7 295 59 30 7.8 4.3 | -52.9 -63.2 290 55 28 7.8 4.3
34000 -47.9 -54.2 295 56 29 7.6 4.2 | -48.1 -54.6 295 52 27 7.9 4.3
32000 -42.8 -45.0 300 52 27 7.6 4.2 | -42.8 -45.0 295 50 26 7.9 4.3
30000 -38.1 -36.6 300 49 25 7.9 4.3 | -38.1 -36.6 295 48 25 7.7 4.2
29000 -35.8 -32.4 300 48 25 7.9 4.3 | -35.8 -32.4 295 48 25 7.7 4.2
28000 -33.4 -28.1 300 47 24 7.9 4.3 | -33.5 -28.3 295 47 24 7.8 4.3
27000 -31.1 -24.0 300 46 24 7.7 4.2 | -31.2 -24.2 295 47 24 7.5 4.1
26000 -28.8 -19.8 300 45 23 7.7 4.2 | -29.0 -20.2 295 46 24 7.5 4.1
25000 -26.5 -15.7 300 45 23 7.7 4.2 | -26.7 -16.1 295 46 23 7.5 4.1
24000 -24.2 -11.6 300 44 23 7.7 4.2 | -24.5 -12.1 295 45 23 7.6 4.2
23000 -21.9 -7.4 300 43 22 7.7 4.2 | -22.2 -8.0 295 44 23 7.6 4.2
22000 -19.6 -3.3 305 42 21 7.7 4.2 | -20.0 -4.0 300 43 22 7.6 4.2
21000 -17.4 0.7 305 40 21 7.2 3.9 | -17.8 -0.0 300 42 21 7.2 4.0
20000 -15.3 4.5 305 38 20 7.1 3.9 | -15.6 3.9 305 40 21 7.2 4.0
19500 -14.2 6.4 310 37 19 7.1 3.9 | -14.5 5.9 305 39 20 7.2 4.0
19000 -13.2 8.2 310 36 18 7.1 3.9 | -13.5 7.7 305 39 20 7.1 3.9
18500 -12.1 10.2 310 35 18 7.0 3.8 | -12.4 9.7 310 38 20 6.7 3.7
18000 -11.1 12.0 310 34 17 7.0 3.8 | -11.4 11.5 310 37 19 6.8 3.7
17500 -10.0 14.0 315 33 17 7.0 3.8 | -9.9 14.2 310 36 19 7.0 3.8
17000 -9.0 15.8 315 32 17 7.0 3.9 | -8.8 16.2 315 35 18 7.0 3.8
16500 -8.0 17.6 315 32 16 7.1 3.9 | -7.8 18.0 315 34 18 7.2 3.9
16000 -6.3 20.7 320 31 16 7.3 4.0 | -6.7 19.9 315 34 17 7.2 3.9
15500 -5.3 22.5 325 30 16 7.5 4.1 | -5.6 21.9 315 33 17 7.2 4.0
15000 -4.1 24.6 325 30 16 7.6 4.2 | -4.6 23.7 320 33 17 7.2 4.0
14500 -3.0 26.6 325 30 15 7.6 4.2 | -3.5 25.7 320 32 17 7.3 4.0
14000 -1.9 28.6 325 30 15 7.8 4.3 | -2.4 27.7 320 31 16 7.4 4.1
13500 -0.7 30.7 330 30 15 7.8 4.3 | -1.3 29.7 320 31 16 7.4 4.1
13000 0.5 32.9 330 30 15 7.9 4.3 | -0.2 31.6 320 30 15 7.4 4.1
12500 1.6 34.9 330 30 16 7.9 4.3 | 0.9 33.6 320 29 15 7.4 4.1
12000 2.8 37.0 330 30 15 7.8 4.3 | 2.0 35.6 320 28 15 7.5 4.1
11500 4.0 39.2 325 30 15 7.8 4.3 | 3.1 37.6 320 28 14 7.6 4.1
11000 5.1 41.2 325 30 15 7.2 3.9 | 4.2 39.6 320 27 14 7.1 3.9
10500 6.1 43.0 320 30 15 7.0 3.9 | 5.2 41.4 315 27 14 7.0 3.9
10250 6.5 43.7 320 30 15 2.7 1.5 | 5.7 42.3 315 27 14 3.6 2.0
10000 6.7 44.1 320 29 15 5.2 2.8 | 5.9 42.6 315 27 14 5.9 3.2
9750 7.4 45.3 320 29 15 9.9 5.4 | 6.6 43.9 315 27 14 10.0 5.5
9500 8.0 46.4 315 29 15 8.4 4.6 | 7.2 45.0 310 26 14 8.8 4.8
9250 8.6 47.5 315 29 15 4.4 2.4 | 7.8 46.0 310 26 13 5.7 3.2
9000 8.8 47.8 315 28 15 5.3 2.9 | 8.2 46.8 310 26 14 6.7 3.7
8750 9.4 48.9 310 28 15 9.8 5.4 | 8.9 48.0 310 26 13 10.4 5.7
8500 10.1 50.2 310 28 14 8.1 4.4 | 9.6 49.3 305 26 13 8.7 4.7
8250 10.6 51.1 305 28 15 5.9 3.2 | 10.2 50.4 305 26 13 6.3 3.4
8000 11.0 51.8 305 29 15 5.7 3.1 | 10.6 51.1 305 27 14 6.3 3.4
7750 11.6 52.9 305 30 15 8.5 4.7 | 11.2 52.2 300 26 13 8.7 4.7
7500 12.2 54.0 300 29 15 6.7 3.7 | 11.8 53.2 300 25 13 8.4 4.6
7250 12.5 54.5 300 30 16 3.6 2.0 | 12.4 54.3 300 24 12 7.2 4.0
7000 12.8 55.0 295 31 16 4.3 2.4 | 13.0 55.4 300 23 12 7.7 4.2
6750 13.2 55.8 295 31 16 6.7 3.7 | 13.6 56.5 300 22 11 11.4 6.2
6500 13.7 56.7 290 28 14 4.0 2.2 | 14.6 58.3 300 20 11 11.4 6.2
6250 13.8 56.8 290 25 13 -0.3 -0.2 | 15.3 59.5 300 20 10 9.0 4.9
6000 13.8 56.8 285 22 11 2.3 1.3 | 16.0 60.8 300 19 10 9.2 5.1
5750 13.9 57.0 285 19 10 -3.7 -2.0 | 16.7 62.1 300 18 9 11.7 6.4
5500 13.1 55.6 275 12 6 -17.8 -9.7 | 17.8 64.0 300 15 8 17.7 9.7
11/11/2025 AT 1400 MST | 11/11/2025 AT 1700 MST
|
CAPE... 0.0 LI... +4.8 | CAPE... 0.0 LI... +4.4
CINH... -0.1 K INDEX... +8.3 | CINH... -0.1 K INDEX... +10.8
|
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 -65.8 -86.4 290 36 18 0.2 0.1 | -65.0 -85.0 300 37 19 0.5 0.3
45000 -65.2 -85.4 295 58 30 2.2 1.2 | -64.0 -83.2 300 54 28 1.5 0.8
40000 -61.8 -79.2 285 58 30 1.9 1.1 | -61.8 -79.2 295 54 28 1.3 0.7
38000 -57.8 -72.0 285 56 29 7.6 4.2 | -58.1 -72.6 295 53 28 7.2 4.0
36000 -53.3 -63.9 290 54 28 7.6 4.2 | -53.8 -64.8 295 52 27 7.2 4.0
34000 -48.7 -55.7 290 52 27 7.9 4.4 | -49.2 -56.6 295 51 26 8.2 4.5
32000 -43.9 -47.0 295 51 26 7.9 4.4 | -43.7 -46.7 295 50 26 8.2 4.5
30000 -38.5 -37.3 295 50 26 8.1 4.4 | -38.8 -37.8 300 49 25 8.1 4.5
29000 -36.1 -33.0 295 50 26 8.1 4.4 | -36.4 -33.5 300 49 25 8.1 4.5
28000 -33.6 -28.5 300 50 26 8.1 4.4 | -33.9 -29.0 300 48 25 8.1 4.5
27000 -31.3 -24.3 300 49 25 7.9 4.3 | -31.6 -24.9 305 47 24 7.8 4.3
26000 -28.9 -20.0 300 48 25 7.9 4.3 | -29.2 -20.6 305 45 23 7.8 4.3
25000 -26.6 -15.9 300 48 24 7.9 4.3 | -26.9 -16.4 305 44 22 7.8 4.3
24000 -24.3 -11.7 300 47 24 7.6 4.2 | -24.6 -12.3 305 42 22 7.7 4.2
23000 -22.0 -7.6 300 45 23 7.6 4.2 | -22.3 -8.1 305 41 21 7.7 4.2
22000 -19.7 -3.5 300 44 23 7.6 4.2 | -20.0 -4.0 305 40 21 7.7 4.2
21000 -17.5 0.5 305 43 22 7.3 4.0 | -17.8 -0.0 310 39 20 7.3 4.0
20000 -15.4 4.3 305 42 22 7.3 4.0 | -15.6 3.9 310 38 20 7.3 4.0
19500 -14.3 6.3 305 41 21 7.3 4.0 | -14.5 5.9 310 38 20 7.3 4.0
19000 -13.2 8.2 305 41 21 7.2 4.0 | -13.4 7.9 310 37 19 7.2 3.9
18500 -12.2 10.0 305 40 21 7.0 3.8 | -12.4 9.7 310 37 19 6.4 3.5
18000 -11.1 12.0 305 39 20 7.0 3.8 | -11.5 11.3 310 36 19 6.5 3.5
17500 -10.1 13.8 310 38 20 6.4 3.5 | -10.6 12.9 310 35 18 6.1 3.4
17000 -9.2 15.4 310 37 19 6.3 3.4 | -9.7 14.5 310 34 17 6.1 3.3
16500 -8.3 17.1 310 36 18 6.3 3.4 | -8.4 16.9 305 32 16 6.3 3.5
16000 -6.9 19.6 310 33 17 6.3 3.5 | -7.4 18.7 305 30 16 6.3 3.5
15500 -5.9 21.4 310 32 16 6.4 3.5 | -6.5 20.3 305 28 15 6.7 3.7
15000 -5.0 23.0 310 30 16 6.5 3.5 | -5.4 22.3 305 27 14 7.0 3.8
14500 -4.0 24.8 310 29 15 6.6 3.6 | -4.4 24.1 305 26 13 7.2 3.9
14000 -3.0 26.6 310 28 14 7.1 3.9 | -3.3 26.1 305 25 13 7.6 4.2
13500 -1.9 28.6 310 27 14 7.1 3.9 | -2.1 28.2 305 24 12 7.7 4.2
13000 -0.8 30.6 310 26 14 7.8 4.3 | -0.9 30.4 305 24 12 8.3 4.6
12500 0.3 32.5 310 26 13 7.7 4.2 | 0.3 32.5 305 23 12 8.3 4.5
12000 1.5 34.7 305 26 13 8.0 4.4 | 1.5 34.7 300 23 12 8.3 4.5
11500 2.6 36.7 305 25 13 7.9 4.4 | 2.7 36.9 300 22 11 8.2 4.5
11000 3.8 38.8 305 25 13 8.2 4.5 | 4.0 39.2 295 22 11 8.6 4.7
10500 5.1 41.2 300 24 12 7.8 4.3 | 5.3 41.5 295 22 11 8.0 4.4
10250 5.5 41.9 300 24 12 4.0 2.2 | 5.7 42.3 295 21 11 4.3 2.4
10000 5.8 42.4 300 24 12 7.0 3.9 | 6.1 43.0 295 21 11 8.0 4.4
9750 6.6 43.9 300 23 12 11.6 6.3 | 6.9 44.4 295 20 11 12.5 6.9
9500 7.4 45.3 300 22 11 10.2 5.6 | 7.8 46.0 295 20 10 11.0 6.0
9250 8.0 46.4 300 22 11 5.9 3.2 | 8.5 47.3 295 20 10 6.4 3.5
9000 8.4 47.1 300 21 11 7.6 4.2 | 8.9 48.0 295 20 10 7.5 4.1
8750 9.3 48.7 300 21 11 12.6 6.9 | 9.7 49.5 295 19 10 12.0 6.6
8500 10.1 50.2 300 20 10 10.4 5.7 | 10.5 50.9 300 19 10 9.8 5.4
8250 10.8 51.4 300 20 10 8.4 4.6 | 11.2 52.2 300 19 10 7.5 4.1
8000 11.4 52.5 300 20 10 8.6 4.7 | 11.7 53.1 300 19 10 7.6 4.2
7750 12.2 54.0 300 19 10 11.9 6.6 | 12.4 54.3 300 18 9 10.4 5.7
7500 13.1 55.6 300 19 10 10.3 5.6 | 13.2 55.8 305 17 9 9.1 5.0
7250 13.7 56.7 300 19 10 7.3 4.0 | 13.7 56.7 305 17 9 6.7 3.7
7000 14.3 57.7 300 19 10 8.3 4.5 | 14.2 57.6 305 17 9 7.5 4.1
6750 15.0 59.0 300 18 9 12.4 6.8 | 14.9 58.8 310 16 8 10.6 5.8
6500 16.0 60.8 305 17 9 11.6 6.4 | 15.7 60.3 310 14 7 9.6 5.3
6250 16.7 62.1 300 17 9 8.5 4.7 | 16.2 61.2 310 14 7 6.1 3.3
6000 17.4 63.3 300 16 8 9.1 5.0 | 16.8 62.2 315 13 7 8.9 4.9
5750 18.1 64.6 300 16 8 11.9 6.5 | 17.3 63.1 315 12 6 1.9 1.0
5500 19.2 66.6 305 13 7 17.8 9.8 | 16.8 62.2 315 8 4 -16.0 -8.8
________________________________________________________________________________
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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