147
UXUS97 KBOU 130122
SRGBOU
SOARING FORECAST
NATIONAL WEATHER SERVICE DENVER/BOULDER, COLORADO
1821 MST MONDAY, JANUARY 12, 2026
THIS FORECAST IS FOR TUESDAY, JANUARY 13, 2026:
IF THE TRIGGER TEMPERATURE OF 62.9 F/17.2 C IS REACHED...THEN
THERMAL SOARING INDEX....................... FAIR
MAXIMUM RATE OF LIFT........................ 249 FT/MIN (1.3 M/S)
MAXIMUM HEIGHT OF THERMALS.................. 8863 FT MSL (3642 FT AGL)
FORECAST MAXIMUM TEMPERATURE................... 62.0 F/17.1 C
TIME OF TRIGGER TEMPERATURE.................... 1415 MST
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................. 6556 FT MSL (1335 FT AGL)
THERMAL SOARING OUTLOOK FOR WEDNESDAY 01/14.... FAIR
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)................ WEAK PVA
POTENTIAL HEIGHT OF WAVE....................... 18976 FT MSL (13755 FT AGL)
WAVE SOARING OUTLOOK FOR WEDNESDAY 01/14....... POOR
REMARKS...
SUNRISE/SUNSET.................... 07:19:24 / 16:57:08 MST
TOTAL POSSIBLE SUNSHINE........... 9 HR 37 MIN 44 SEC (577 MIN 44 SEC)
ALTITUDE OF SUN AT 12:08:16 MST... 28.83 DEGREES
UPPER AIR DATA FROM NUMERICAL MODEL FORECAST VALID ON 01/13/2026 AT 0500 MST
FREEZING LEVEL.................. 11675 FT MSL (6454 FT AGL)
CONVECTIVE CONDENSATION LEVEL... 19451 FT MSL (14230 FT AGL)
LIFTED CONDENSATION LEVEL....... 15236 FT MSL (10015 FT AGL)
LIFTED INDEX.................... +7.1
K INDEX......................... +5.2
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 -61.4 -78.5 345 36 18 1.5 0.8 M M M M M
45000 -59.3 -74.7 340 39 20 -2.2 -1.2 M M M M M
40000 -64.8 -84.6 360 38 20 -3.8 -2.1 M M M M M
38000 -63.0 -81.4 010 47 24 6.6 3.6 M M M M M
36000 -59.1 -74.4 010 59 30 6.6 3.6 M M M M M
34000 -54.5 -66.1 010 61 31 9.2 5.1 M M M M M
32000 -49.0 -56.2 010 47 24 9.2 5.1 M M M M M
30000 -43.4 -46.1 360 37 19 9.4 5.1 32.0 89.7 11.6 M M
29000 -40.6 -41.1 355 35 18 9.4 5.1 31.9 89.3 11.6 M M
28000 -37.8 -36.0 350 32 17 9.4 5.1 31.8 89.2 11.7 M M
27000 -35.0 -31.0 345 30 16 9.2 5.1 31.7 89.0 11.7 M M
26000 -32.2 -26.0 340 28 15 9.2 5.1 31.4 88.5 11.6 M M
25000 -29.5 -21.1 335 26 14 9.2 5.1 31.2 88.2 11.6 M M
24000 -26.1 -15.0 330 25 13 8.5 4.7 30.9 87.6 11.6 M M
23000 -23.6 -10.5 325 26 13 8.5 4.7 30.4 86.7 11.3 M M
22000 -21.1 -6.0 320 26 13 8.5 4.7 30.0 86.0 11.1 M M
21000 -18.6 -1.5 325 27 14 7.8 4.3 29.4 84.9 10.7 M M
20000 -16.3 2.7 325 28 15 7.8 4.3 28.7 83.7 10.2 M M
19500 -15.1 4.8 330 29 15 7.8 4.3 28.4 83.1 10.0 M M
19000 -14.0 6.8 330 30 15 7.5 4.1 28.1 82.6 9.8 M M
18500 -12.9 8.8 330 30 15 6.9 3.8 27.6 81.7 9.4 M M
18000 -11.9 10.6 330 30 16 7.0 3.8 27.1 80.8 9.0 M M
17500 -11.0 12.2 330 31 16 5.7 3.1 26.6 79.8 8.5 M M
17000 -10.1 13.8 330 31 16 5.7 3.1 25.9 78.5 7.9 M M
16500 -9.3 15.3 330 31 16 5.5 3.0 25.2 77.3 7.4 M M
16000 -8.6 16.5 330 30 16 5.3 2.9 24.4 75.9 6.7 M M
15500 -7.8 18.0 330 30 15 5.3 2.9 23.7 74.6 6.0 M M
15000 -7.0 19.4 330 29 15 6.1 3.4 23.0 73.4 5.5 M M
14500 -6.1 21.0 330 27 14 6.0 3.3 22.4 72.3 4.9 M M
14000 -5.1 22.8 325 25 13 7.0 3.8 21.8 71.3 4.4 M M
13500 -4.1 24.6 325 22 12 6.9 3.8 21.4 70.5 4.0 M M
13000 -3.1 26.4 320 20 10 7.2 3.9 20.9 69.7 3.6 M M
12500 -2.0 28.4 315 18 9 7.2 3.9 20.5 68.9 3.2 M M
12000 -1.0 30.2 315 15 8 7.4 4.1 20.1 68.2 2.8 M M
11500 0.2 32.4 310 13 7 7.5 4.1 19.7 67.5 2.5 M M
11000 1.2 34.2 305 12 6 7.3 4.0 19.4 66.9 2.1 M M
10500 2.9 37.2 300 10 5 6.1 3.3 18.8 65.8 1.6 M M
10250 3.2 37.8 300 9 5 1.8 1.0 18.3 65.0 1.2 M M
10000 3.4 38.1 300 9 5 6.1 3.4 17.7 63.9 0.6 M M
9750 4.1 39.4 300 8 4 11.7 6.4 17.8 64.0 0.7 M M
9500 4.9 40.8 300 8 4 8.2 4.5 17.8 64.1 0.7 M M
9250 5.3 41.5 305 7 4 4.5 2.5 17.5 63.5 0.4 M M
9000 5.6 42.1 305 7 4 6.0 3.3 17.1 62.8 0.0 M M
8750 6.3 43.3 305 7 4 10.9 6.0 17.0 62.7 -0.1 227 1.2
8500 7.0 44.6 310 7 4 7.8 4.3 17.1 62.8 -0.0 196 1.0
8250 7.4 45.3 305 7 4 3.6 2.0 16.7 62.1 -0.4 178 0.9
8000 7.8 46.0 300 7 3 5.4 2.9 16.3 61.4 -0.8 160 0.8
7750 8.2 46.8 295 7 3 8.3 4.5 16.1 60.9 -1.0 138 0.7
7500 8.9 48.0 285 6 3 6.4 3.5 16.0 60.7 -1.1 112 0.6
7250 9.2 48.6 275 7 3 2.9 1.6 15.5 59.9 -1.6 96 0.5
7000 9.5 49.1 265 7 4 4.7 2.6 15.0 59.1 -2.0 80 0.4
6750 9.7 49.5 260 8 4 0.5 0.3 14.6 58.3 -2.5 64 0.3
6500 9.5 49.1 255 9 5 -3.6 -2.0 13.6 56.6 -3.4 63 0.3
6250 9.3 48.7 255 10 5 -1.3 -0.7 12.7 54.9 -4.4 62 0.3
6000 9.1 48.4 255 11 6 -6.4 -3.5 11.8 53.2 -5.3 60 0.3
5750 8.0 46.4 250 11 6 -26.5 -14.5 9.9 49.8 -7.2 87 0.4
5500 5.2 41.4 235 9 4 -45.4 -24.9 6.4 43.5 -10.8 165 0.8
* * * * * * NUMERICAL WEATHER PREDICTION MODEL FORECAST DATA VALID * * * * * *
01/13/2026 AT 0800 MST | 01/13/2026 AT 1100 MST
|
CAPE... 0.0 LI... +5.6 | CAPE... 0.0 LI... +5.8
CINH... -0.1 K INDEX... +8.2 | CINH... 0.0 K INDEX... +9.2
|
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 -60.9 -77.6 355 37 19 1.1 0.6 | -60.4 -76.7 355 39 20 1.2 0.7
45000 -59.3 -74.7 350 49 25 -1.4 -0.8 | -58.7 -73.7 355 47 24 -1.3 -0.7
40000 -64.3 -83.7 010 44 22 -3.1 -1.7 | -63.4 -82.1 345 42 22 -2.9 -1.6
38000 -62.4 -80.3 010 46 24 6.0 3.3 | -61.5 -78.7 350 47 24 6.0 3.3
36000 -58.8 -73.8 005 50 26 6.0 3.3 | -57.9 -72.2 355 54 28 6.0 3.3
34000 -54.5 -66.1 360 51 26 9.3 5.1 | -53.6 -64.5 355 58 30 9.0 4.9
32000 -48.9 -56.0 355 45 23 9.3 5.1 | -48.3 -54.9 355 54 28 9.0 4.9
30000 -43.4 -46.1 345 40 21 9.2 5.0 | -42.9 -45.2 350 50 26 9.1 5.0
29000 -40.6 -41.1 345 38 20 9.2 5.0 | -39.4 -38.9 345 47 24 9.1 5.0
28000 -37.2 -35.0 335 36 19 9.2 5.0 | -36.7 -34.1 345 44 23 9.1 5.0
27000 -34.5 -30.1 335 36 18 9.1 5.0 | -34.0 -29.2 340 43 22 9.0 5.0
26000 -31.8 -25.2 330 37 19 9.1 5.0 | -31.3 -24.3 335 43 22 9.0 5.0
25000 -29.0 -20.2 330 37 19 9.1 5.0 | -28.6 -19.5 335 44 23 9.0 5.0
24000 -26.4 -15.5 330 38 19 8.7 4.8 | -26.0 -14.8 335 43 22 8.2 4.5
23000 -23.8 -10.8 330 37 19 8.7 4.8 | -23.5 -10.3 335 41 21 8.3 4.5
22000 -21.2 -6.2 325 36 18 8.7 4.8 | -21.1 -6.0 330 39 20 8.3 4.5
21000 -18.8 -1.8 325 35 18 6.9 3.8 | -18.8 -1.8 330 38 19 6.9 3.8
20000 -16.8 1.8 325 35 18 6.9 3.8 | -16.8 1.8 330 38 19 6.9 3.8
19500 -15.8 3.6 325 34 18 6.9 3.8 | -15.8 3.6 330 37 19 6.9 3.8
19000 -14.8 5.4 325 34 17 6.7 3.7 | -14.7 5.5 330 37 19 6.8 3.7
18500 -13.8 7.2 330 33 17 6.0 3.3 | -13.8 7.2 330 37 19 6.0 3.3
18000 -12.9 8.8 330 33 17 6.1 3.3 | -12.9 8.8 330 37 19 6.1 3.4
17500 -12.1 10.2 330 32 17 5.8 3.2 | -12.0 10.4 330 37 19 5.7 3.1
17000 -11.2 11.8 330 32 16 5.8 3.2 | -11.2 11.8 330 37 19 5.7 3.1
16500 -10.4 13.3 330 31 16 5.9 3.2 | -10.4 13.3 330 36 19 5.8 3.2
16000 -9.5 14.9 330 31 16 6.0 3.3 | -9.5 14.9 330 35 18 6.1 3.4
15500 -8.6 16.5 330 30 15 6.0 3.3 | -8.6 16.5 330 34 18 6.1 3.4
15000 -7.7 18.1 330 29 15 6.4 3.5 | -7.7 18.1 330 32 17 6.4 3.5
14500 -6.3 20.7 330 27 14 6.6 3.6 | -6.2 20.8 330 29 15 6.4 3.5
14000 -5.3 22.5 330 25 13 6.9 3.8 | -5.3 22.5 330 27 14 6.6 3.6
13500 -4.2 24.4 330 23 12 7.0 3.8 | -4.3 24.3 330 26 13 6.6 3.6
13000 -3.2 26.2 330 21 11 7.2 4.0 | -3.3 26.1 330 24 13 7.0 3.9
12500 -2.1 28.2 325 19 10 7.2 4.0 | -2.2 28.0 335 23 12 7.0 3.9
12000 -1.1 30.0 325 17 9 7.3 4.0 | -1.1 30.0 335 22 11 7.5 4.1
11500 0.0 32.0 325 16 8 7.3 4.0 | -0.0 32.0 335 21 11 7.5 4.1
11000 1.1 34.0 320 14 7 7.3 4.0 | 1.2 34.2 335 20 11 8.0 4.4
10500 2.2 36.0 315 13 7 6.5 3.6 | 2.4 36.3 335 20 10 7.1 3.9
10250 2.5 36.5 315 12 6 1.5 0.8 | 2.7 36.9 335 19 10 1.9 1.1
10000 2.7 36.9 310 11 6 6.2 3.4 | 2.9 37.2 335 18 9 6.6 3.6
9750 3.5 38.3 305 11 6 12.8 7.0 | 3.7 38.7 330 18 9 13.2 7.2
9500 4.3 39.7 305 11 6 9.2 5.1 | 4.6 40.3 330 19 10 9.9 5.4
9250 4.8 40.6 300 11 6 5.0 2.8 | 5.2 41.4 330 19 10 5.8 3.2
9000 5.2 41.4 295 10 5 6.4 3.5 | 5.6 42.1 330 18 9 6.6 3.6
8750 5.9 42.6 295 11 6 11.9 6.5 | 6.3 43.3 325 18 9 10.8 6.0
8500 6.8 44.2 295 12 6 9.8 5.4 | 7.1 44.8 320 19 10 8.8 4.8
8250 7.3 45.1 295 12 6 6.3 3.5 | 7.6 45.7 320 19 10 5.8 3.2
8000 7.8 46.0 295 12 6 7.3 4.0 | 8.0 46.4 315 19 10 6.7 3.7
7750 8.4 47.1 290 12 6 9.2 5.1 | 8.6 47.5 315 19 10 9.4 5.2
7500 9.1 48.4 290 14 7 7.4 4.0 | 9.3 48.7 315 19 10 7.3 4.0
7250 9.5 49.1 290 15 7 4.3 2.4 | 9.7 49.5 310 19 10 3.9 2.1
7000 9.9 49.8 290 15 8 6.4 3.5 | 10.0 50.0 310 19 10 5.6 3.1
6750 10.3 50.5 290 16 8 0.9 0.5 | 10.5 50.9 305 19 10 6.5 3.6
6500 10.0 50.0 285 16 8 -5.7 -3.1 | 10.9 51.6 300 17 9 2.8 1.5
6250 9.6 49.3 280 15 8 -5.1 -2.8 | 10.9 51.6 295 14 7 0.0 0.0
6000 9.2 48.6 270 15 8 -5.8 -3.2 | 10.9 51.6 290 12 6 1.0 0.5
5750 8.3 46.9 265 14 7 -23.4 -12.8 | 11.0 51.8 290 10 5 3.2 1.7
5500 5.4 41.7 250 9 5 -50.5 -27.7 | 11.3 52.3 290 7 4 6.8 3.7
01/13/2026 AT 1400 MST | 01/13/2026 AT 1700 MST
|
CAPE... 0.0 LI... +5.5 | CAPE... 0.0 LI... +5.9
CINH... 0.0 K INDEX... +10.9 | CINH... 0.0 K INDEX... +12.0
|
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 -60.7 -77.3 345 42 22 1.0 0.6 | -60.9 -77.6 345 45 23 0.9 0.5
45000 -59.2 -74.6 345 51 26 -0.9 -0.5 | -59.5 -75.1 345 52 27 -1.3 -0.7
40000 -62.7 -80.9 345 63 32 -2.1 -1.2 | -64.1 -83.4 350 87 45 -2.7 -1.5
38000 -60.6 -77.1 350 66 34 6.2 3.4 | -61.2 -78.2 350 83 43 8.3 4.5
36000 -56.9 -70.4 350 68 35 6.2 3.4 | -56.2 -69.2 345 73 38 8.3 4.5
34000 -52.5 -62.5 355 68 35 9.1 5.0 | -51.2 -60.2 340 65 34 8.7 4.8
32000 -47.1 -52.8 350 64 33 9.1 5.0 | -46.0 -50.8 345 62 32 8.7 4.8
30000 -41.8 -43.2 345 60 31 8.5 4.7 | -40.9 -41.6 345 61 31 7.9 4.3
29000 -39.2 -38.6 345 58 30 8.6 4.7 | -38.6 -37.5 345 61 32 7.8 4.3
28000 -36.7 -34.1 345 56 29 8.6 4.7 | -36.3 -33.3 345 62 32 7.9 4.3
27000 -34.1 -29.4 340 54 28 8.6 4.7 | -33.3 -27.9 340 61 31 8.0 4.4
26000 -30.9 -23.6 335 52 27 8.6 4.7 | -30.9 -23.6 340 58 30 8.0 4.4
25000 -28.3 -18.9 335 49 25 8.6 4.7 | -28.5 -19.3 335 56 29 8.0 4.4
24000 -25.7 -14.3 330 47 24 8.6 4.7 | -26.1 -15.0 335 54 28 8.2 4.5
23000 -23.2 -9.8 330 45 23 8.6 4.7 | -23.7 -10.7 330 50 26 8.2 4.5
22000 -20.6 -5.1 330 43 22 8.6 4.7 | -21.3 -6.3 325 46 24 8.1 4.5
21000 -18.4 -1.1 330 42 21 6.1 3.3 | -19.1 -2.4 325 43 22 6.3 3.4
20000 -16.6 2.1 330 40 21 6.1 3.3 | -17.2 1.0 325 40 20 6.3 3.5
19500 -15.7 3.7 330 39 20 6.1 3.3 | -16.2 2.8 325 38 19 6.4 3.5
19000 -14.8 5.4 330 39 20 6.1 3.3 | -15.3 4.5 325 36 19 6.5 3.5
18500 -14.0 6.8 330 38 20 4.8 2.6 | -14.5 5.9 330 36 19 4.8 2.7
18000 -13.3 8.1 330 39 20 4.9 2.7 | -13.8 7.2 335 39 20 5.0 2.8
17500 -12.6 9.3 330 39 20 5.8 3.2 | -13.0 8.6 340 41 21 5.3 2.9
17000 -11.7 10.9 330 37 19 6.2 3.4 | -12.2 10.0 335 40 20 5.5 3.0
16500 -10.7 12.7 330 35 18 6.2 3.4 | -11.4 11.5 335 38 20 5.4 3.0
16000 -9.8 14.4 325 33 17 6.2 3.4 | -10.6 12.9 335 37 19 4.7 2.6
15500 -8.9 16.0 325 31 16 6.2 3.4 | -9.9 14.2 335 37 19 4.7 2.6
15000 -8.0 17.6 325 29 15 6.1 3.4 | -9.1 15.6 335 36 18 6.2 3.4
14500 -7.1 19.2 320 27 14 6.1 3.4 | -8.2 17.2 335 34 18 6.1 3.4
14000 -6.2 20.8 320 25 13 6.1 3.4 | -7.3 18.9 335 33 17 6.3 3.5
13500 -5.2 22.6 320 23 12 6.1 3.4 | -6.4 20.5 335 31 16 6.4 3.5
13000 -4.3 24.3 325 22 11 6.4 3.5 | -5.4 22.3 335 30 15 6.1 3.3
12500 -3.4 25.9 325 21 11 6.5 3.5 | -4.5 23.9 335 29 15 5.9 3.2
12000 -2.4 27.7 325 20 10 7.0 3.8 | -3.7 25.3 335 28 15 6.1 3.4
11500 -1.3 29.7 325 19 10 7.3 4.0 | -2.7 27.1 335 27 14 6.3 3.5
11000 0.4 32.7 325 20 10 7.7 4.2 | -1.2 29.8 335 26 13 7.9 4.4
10500 1.5 34.7 325 20 10 7.6 4.1 | -0.0 32.0 335 24 12 8.0 4.4
10250 2.0 35.6 325 20 11 2.7 1.5 | 0.4 32.7 335 23 12 2.2 1.2
10000 2.1 35.8 325 20 11 6.0 3.3 | 0.5 32.9 335 23 12 5.7 3.1
9750 2.9 37.2 325 21 11 12.2 6.7 | 1.4 34.5 330 22 11 13.1 7.2
9500 3.8 38.8 325 21 11 9.6 5.3 | 2.2 36.0 330 21 11 10.0 5.5
9250 4.3 39.7 325 21 11 5.0 2.7 | 2.8 37.0 330 20 10 5.5 3.0
9000 4.6 40.3 325 21 11 5.8 3.2 | 3.2 37.8 330 20 10 5.9 3.2
8750 5.3 41.5 320 21 11 11.7 6.4 | 3.9 39.0 330 19 10 12.3 6.7
8500 6.2 43.2 320 21 11 9.1 5.0 | 4.8 40.6 330 19 10 10.2 5.6
8250 6.6 43.9 315 21 11 4.5 2.5 | 5.3 41.5 325 19 10 5.6 3.1
8000 7.0 44.6 315 21 11 5.1 2.8 | 5.7 42.3 325 19 10 6.1 3.3
7750 7.5 45.5 310 21 11 9.9 5.5 | 6.3 43.3 325 18 10 11.0 6.1
7500 8.3 46.9 310 21 11 8.2 4.5 | 7.2 45.0 320 19 10 9.5 5.2
7250 8.7 47.7 310 19 10 4.2 2.3 | 7.7 45.9 320 19 10 5.2 2.9
7000 9.0 48.2 310 18 9 5.2 2.8 | 8.1 46.6 315 19 10 6.3 3.5
6750 9.5 49.1 310 17 9 10.2 5.6 | 8.7 47.7 315 19 10 10.2 5.6
6500 10.5 50.9 310 15 8 11.0 6.0 | 9.5 49.1 315 18 9 9.4 5.2
6250 11.1 52.0 310 14 7 8.7 4.8 | 10.0 50.0 315 17 8 6.1 3.4
6000 11.7 53.1 310 13 7 6.2 3.4 | 10.5 50.9 315 15 8 5.9 3.2
5750 12.0 53.6 310 13 6 4.7 2.6 | 10.7 51.3 310 15 8 -1.8 -1.0
5500 12.6 54.7 310 10 5 13.1 7.2 | 10.2 50.4 310 10 5 -9.7 -5.3
________________________________________________________________________________
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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