617
UXUS97 KGJT 011305
SRGGJT
SOARING FORECAST
NATIONAL WEATHER SERVICE GRAND JUNCTION, COLORADO
705 AM MDT TUESDAY, SEPTEMBER 1, 2026
THIS FORECAST IS FOR TUESDAY, SEPTEMBER 1, 2026:
IF THE TRIGGER TEMPERATURE OF 75.4 F/24.1 C IS REACHED...THEN
THERMAL SOARING INDEX....................... EXCELLENT
MAXIMUM RATE OF LIFT........................ 1176 FT/MIN (6.0 M/S)
MAXIMUM HEIGHT OF THERMALS.................. 16116 FT MSL (10508 FT AGL)
FORECAST MAXIMUM TEMPERATURE................... 81.0 F/27.7 C
TIME OF TRIGGER TEMPERATURE.................... 1230 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................. 10568 FT MSL (4961 FT AGL)
THERMAL SOARING OUTLOOK FOR WEDNESDAY 09/02.... EXCELLENT
WAVE SOARING INDEX............................. NOT AVAILABLE
REMARKS...
SUNRISE/SUNSET.................... 06:43:14 / 19:44:53 MDT
TOTAL POSSIBLE SUNSHINE........... 13 HR 1 MIN 39 SEC (781 MIN 39 SEC)
ALTITUDE OF SUN AT 13:14:04 MDT... 58.78 DEGREES
UPPER AIR DATA FROM RAWINSONDE OBSERVATION TAKEN ON 09/01/2026 AT 0600 MDT
FREEZING LEVEL.................. 14190 FT MSL (8582 FT AGL)
CONVECTIVE CONDENSATION LEVEL... 13974 FT MSL (8366 FT AGL)
LIFTED CONDENSATION LEVEL....... 14716 FT MSL (9108 FT AGL)
LIFTED INDEX.................... +0.0
K INDEX......................... +27.2
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 -63.8 -82.8 235 56 29 2.1 1.2 M M M M M
45000 -58.9 -74.0 235 76 39 5.9 3.2 M M M M M
40000 -49.4 -56.9 235 81 42 6.4 3.5 M M M M M
38000 -45.5 -49.9 235 79 41 6.4 3.5 M M M M M
36000 -41.7 -43.1 235 77 40 6.4 3.5 M M M M M
34000 -37.7 -35.9 235 74 38 6.7 3.7 M M M M M
32000 -33.6 -28.5 235 69 36 6.6 3.6 M M M M M
30000 -29.5 -21.1 235 65 33 7.0 3.9 46.3 115.4 14.6 M M
29000 -27.4 -17.3 235 63 32 7.0 3.9 45.3 113.5 13.9 M M
28000 -25.3 -13.5 235 60 31 6.9 3.8 44.4 111.9 13.4 M M
27000 -23.3 -9.9 235 58 30 6.4 3.5 43.0 109.5 12.5 M M
26000 -21.4 -6.5 230 55 28 6.4 3.5 41.8 107.2 11.6 M M
25000 -19.5 -3.1 230 52 27 6.4 3.5 40.6 105.1 10.8 M M
24000 -17.5 0.5 230 49 25 6.7 3.7 39.4 103.0 9.9 M M
23000 -15.5 4.1 230 47 24 6.7 3.7 38.3 100.9 9.1 M M
22000 -13.0 8.6 230 44 22 6.1 3.3 37.0 98.6 8.1 M M
21000 -11.4 11.5 230 41 21 5.2 2.8 35.3 95.5 6.8 M M
20000 -9.9 14.2 230 38 20 5.2 2.9 33.7 92.7 5.4 M M
19500 -9.1 15.6 230 37 19 5.3 2.9 33.0 91.4 4.8 M M
19000 -8.4 16.9 230 35 18 4.6 2.5 32.2 89.9 4.1 M M
18500 -7.8 18.0 225 34 17 4.7 2.6 31.3 88.3 3.3 M M
18000 -7.1 19.2 225 32 17 4.9 2.7 30.4 86.8 2.5 M M
17500 -6.4 20.5 225 32 17 5.0 2.8 29.6 85.3 1.7 M M
17000 -5.7 21.7 220 32 17 5.1 2.8 28.8 83.8 1.0 M M
16500 -4.9 23.2 220 32 17 7.0 3.9 28.2 82.7 0.4 M M
16000 -3.9 25.0 220 32 17 6.9 3.8 27.7 81.9 -0.2 963 4.9
15500 -2.9 26.8 220 33 17 7.6 4.2 27.3 81.1 -0.6 919 4.7
15000 -1.8 28.8 220 32 17 7.8 4.3 26.9 80.5 -1.0 871 4.4
14500 -0.7 30.7 220 32 17 8.0 4.4 26.6 79.9 -1.4 823 4.2
14000 0.5 32.9 220 31 16 8.3 4.5 26.4 79.5 -1.7 772 3.9
13500 1.7 35.1 220 29 15 8.5 4.7 26.1 79.0 -1.9 722 3.7
13000 2.9 37.2 220 28 14 9.1 5.0 26.0 78.8 -2.1 669 3.4
12500 4.3 39.7 220 26 13 9.1 5.0 25.9 78.6 -2.3 615 3.1
12000 5.6 42.1 220 25 13 9.3 5.1 25.8 78.4 -2.4 559 2.8
11500 7.0 44.6 220 23 12 9.3 5.1 25.7 78.3 -2.5 503 2.6
11000 8.2 46.8 220 22 11 8.2 4.5 25.5 78.0 -2.7 451 2.3
10500 9.4 48.9 220 21 11 10.9 6.0 25.3 77.5 -3.0 401 2.0
10250 10.4 50.7 220 20 11 11.7 6.4 25.5 77.9 -2.8 365 1.9
10000 11.0 51.8 220 19 10 8.3 4.6 25.5 77.9 -2.9 337 1.7
9750 11.7 53.1 220 18 10 9.9 5.4 25.4 77.8 -2.9 310 1.6
9500 12.4 54.3 220 18 9 7.2 3.9 25.4 77.7 -3.0 282 1.4
9250 12.8 55.0 220 16 8 7.3 4.0 25.1 77.2 -3.3 261 1.3
9000 13.5 56.3 220 15 8 9.6 5.3 25.1 77.1 -3.3 233 1.2
8750 14.2 57.6 220 14 7 9.3 5.1 25.0 77.0 -3.4 205 1.0
8500 14.9 58.8 215 13 7 8.3 4.6 25.0 77.0 -3.4 177 0.9
8250 15.4 59.7 215 12 6 6.2 3.4 24.8 76.6 -3.6 153 0.8
8000 15.9 60.6 210 11 6 5.8 3.2 24.5 76.1 -3.9 133 0.7
7750 16.3 61.3 205 10 5 6.2 3.4 24.2 75.5 -4.2 112 0.6
7500 16.8 62.2 200 8 4 5.4 3.0 23.9 75.0 -4.5 91 0.5
7250 17.1 62.8 185 9 5 4.4 2.4 23.5 74.3 -4.9 72 0.4
7000 17.5 63.5 175 10 5 4.0 2.2 23.1 73.6 -5.3 55 0.3
6750 17.7 63.9 170 9 5 3.3 1.8 22.6 72.7 -5.7 40 0.2
6500 17.9 64.2 160 9 5 0.6 0.3 22.1 71.7 -6.3 27 0.1
6250 17.8 64.0 155 9 5 -2.8 -1.5 21.2 70.2 -7.2 23 0.1
6000 17.8 64.0 145 9 5 3.8 2.1 20.4 68.8 -8.0 17 0.1
5750 18.2 64.8 140 8 4 2.6 1.4 20.1 68.2 -8.3 M M
5500 M M M M M M M M M M M M
5250 M M M M M M M M M M M M
5000 M M M M M M M M M M M M
* * * * * * NUMERICAL WEATHER PREDICTION MODEL FORECAST DATA VALID * * * * * *
09/01/2026 AT 0900 MDT | 09/01/2026 AT 1200 MDT
|
CAPE... +261.9 LI... -0.7 | CAPE... +626.7 LI... -2.0
CINH... -18.3 K INDEX... +26.1 | CINH... -2.4 K INDEX... +25.2
|
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 -61.0 -77.8 245 47 24 2.8 1.5 | -61.4 -78.5 240 51 26 2.7 1.5
45000 -56.2 -69.2 250 61 32 4.1 2.3 | -56.7 -70.1 245 69 35 4.3 2.4
40000 -49.6 -57.3 265 67 34 4.6 2.5 | -50.0 -58.0 260 74 38 4.1 2.2
38000 -46.8 -52.2 265 55 29 4.7 2.6 | -47.5 -53.5 255 64 33 4.1 2.2
36000 -44.0 -47.2 260 45 23 4.6 2.5 | -45.1 -49.2 250 55 28 3.8 2.1
34000 -40.6 -41.1 255 40 20 5.9 3.2 | -40.8 -41.4 245 49 25 7.7 4.2
32000 -37.1 -34.8 250 36 19 5.9 3.2 | -36.1 -33.0 240 44 22 7.7 4.2
30000 -32.4 -26.3 250 33 17 8.4 4.6 | -31.4 -24.5 240 39 20 7.8 4.3
29000 -29.9 -21.8 250 32 17 8.4 4.6 | -29.1 -20.4 240 37 19 7.8 4.3
28000 -27.3 -17.1 245 31 16 8.2 4.5 | -26.8 -16.2 240 34 18 7.7 4.2
27000 -25.1 -13.2 245 30 16 7.4 4.0 | -24.5 -12.1 235 32 17 7.4 4.1
26000 -22.9 -9.2 245 29 15 7.4 4.0 | -22.3 -8.1 235 31 16 7.4 4.1
25000 -20.1 -4.2 245 28 14 7.4 4.1 | -19.5 -3.1 230 29 15 7.4 4.0
24000 -17.9 -0.2 240 27 14 7.6 4.2 | -17.3 0.9 230 28 15 7.3 4.0
23000 -15.6 3.9 240 27 14 7.6 4.2 | -15.2 4.6 230 28 15 7.3 4.0
22000 -13.3 8.1 240 27 14 7.1 3.9 | -13.0 8.6 230 28 15 6.7 3.7
21000 -11.5 11.3 240 27 14 6.0 3.3 | -11.3 11.7 230 28 14 5.8 3.2
20000 -9.8 14.4 240 27 14 6.1 3.3 | -9.6 14.7 235 27 14 5.9 3.2
19500 -8.9 16.0 240 27 14 6.3 3.4 | -8.7 16.3 235 27 14 6.0 3.3
19000 -8.2 17.2 235 27 14 4.6 2.5 | -7.9 17.8 240 26 13 5.7 3.1
18500 -7.5 18.5 235 26 13 4.8 2.7 | -7.1 19.2 240 25 13 5.8 3.2
18000 -6.8 19.8 235 25 13 5.4 2.9 | -6.3 20.7 240 25 13 5.7 3.1
17500 -6.0 21.2 235 24 13 6.0 3.3 | -5.5 22.1 240 24 12 5.5 3.0
17000 -5.1 22.8 240 24 12 6.0 3.3 | -4.7 23.5 235 23 12 5.5 3.0
16500 -4.3 24.3 240 23 12 5.7 3.1 | -4.0 24.8 235 22 11 5.0 2.8
16000 -3.5 25.7 240 22 12 5.8 3.2 | -3.3 26.1 235 21 11 5.0 2.8
15500 -2.6 27.3 240 22 11 6.3 3.4 | -2.5 27.5 235 20 10 6.1 3.3
15000 -1.7 28.9 245 21 11 6.4 3.5 | -1.6 29.1 235 19 10 6.4 3.5
14500 -0.8 30.6 245 21 11 6.6 3.6 | -0.7 30.7 230 18 10 6.8 3.7
14000 0.1 32.2 245 20 10 6.7 3.7 | 0.3 32.5 230 18 9 7.2 4.0
13500 1.1 34.0 250 19 10 6.8 3.7 | 1.4 34.5 230 17 9 7.3 4.0
13000 2.1 35.8 250 18 9 7.2 3.9 | 2.4 36.3 230 17 8 7.6 4.1
12500 3.1 37.6 250 18 9 7.2 3.9 | 3.5 38.3 230 16 8 7.6 4.2
12000 4.1 39.4 250 17 9 6.9 3.8 | 4.5 40.1 230 15 8 7.4 4.1
11500 5.0 41.0 245 17 9 6.9 3.8 | 5.6 42.1 230 15 8 7.5 4.1
11000 6.0 42.8 245 16 8 6.5 3.5 | 6.6 43.9 230 14 7 7.2 4.0
10500 6.9 44.4 240 15 8 6.4 3.5 | 7.6 45.7 225 13 7 6.5 3.5
10250 7.3 45.1 240 14 7 5.8 3.2 | 8.0 46.4 225 12 6 5.6 3.1
10000 7.7 45.9 240 14 7 6.4 3.5 | 8.5 47.3 225 12 6 7.6 4.2
9750 8.2 46.8 235 13 6 7.1 3.9 | 9.1 48.4 225 11 6 8.7 4.8
9500 8.7 47.7 230 11 6 6.9 3.8 | 9.7 49.5 220 10 5 8.2 4.5
9250 9.2 48.6 225 10 5 6.7 3.7 | 10.2 50.4 220 8 4 6.3 3.5
9000 9.6 49.3 220 9 5 6.4 3.5 | 10.6 51.1 220 7 4 7.2 4.0
8750 10.5 50.9 205 8 4 6.2 3.4 | 11.2 52.2 215 7 3 9.3 5.1
8500 11.0 51.8 195 8 4 6.0 3.3 | 12.4 54.3 215 5 3 6.5 3.6
8250 11.4 52.5 190 7 4 6.0 3.3 | 12.8 55.0 210 4 2 7.6 4.2
8000 11.8 53.2 180 7 4 6.2 3.4 | 13.5 56.3 210 4 2 11.2 6.2
7750 12.3 54.1 180 7 3 6.0 3.3 | 14.3 57.7 215 4 2 9.4 5.2
7500 12.7 54.9 170 7 3 5.7 3.1 | 14.9 58.8 215 3 2 6.5 3.5
7250 13.1 55.6 165 7 3 5.9 3.2 | 15.4 59.7 215 2 1 7.7 4.3
7000 13.6 56.5 165 7 3 7.2 4.0 | 16.1 61.0 215 2 1 12.7 7.0
6750 14.1 57.4 160 6 3 7.6 4.2 | 17.1 62.8 215 2 1 11.3 6.2
6500 14.6 58.3 155 6 3 7.0 3.9 | 17.7 63.9 215 2 1 7.7 4.2
6250 15.1 59.2 150 6 3 6.8 3.7 | 18.3 64.9 225 1 1 8.0 4.4
6000 15.7 60.3 150 6 3 10.4 5.7 | 19.0 66.2 230 1 1 14.2 7.8
5750 16.7 62.1 145 5 2 17.1 9.4 | 20.5 68.9 230 1 1 26.8 14.7
5500 17.6 63.7 140 5 2 2.7 1.5 | 21.9 71.4 260 1 0 0.9 0.5
5250 M M M M M M M | M M M M M M M
5000 M M M M M M M | M M M M M M M
09/01/2026 AT 1500 MDT | 09/01/2026 AT 1800 MDT
|
CAPE... +704.4 LI... -2.8 | CAPE... +636.5 LI... -2.6
CINH... -7.8 K INDEX... +28.3 | CINH... -19.9 K INDEX... +28.3
|
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 -61.7 -79.1 235 55 28 2.3 1.3 | -62.1 -79.8 240 57 29 2.3 1.2
45000 -57.2 -71.0 245 75 39 4.6 2.5 | -57.4 -71.3 245 77 40 5.1 2.8
40000 -50.0 -58.0 255 80 41 4.4 2.4 | -49.5 -57.1 250 84 43 4.6 2.5
38000 -47.4 -53.3 250 74 38 4.4 2.4 | -46.8 -52.2 250 79 41 4.6 2.5
36000 -44.7 -48.5 245 68 35 4.1 2.3 | -44.0 -47.2 245 74 38 4.4 2.4
34000 -40.7 -41.3 245 59 30 7.1 3.9 | -40.0 -40.0 245 66 34 6.9 3.8
32000 -36.5 -33.7 240 50 26 7.0 3.8 | -35.9 -32.6 245 59 30 6.9 3.8
30000 -31.4 -24.5 235 45 23 8.7 4.8 | -31.3 -24.3 240 51 26 7.9 4.3
29000 -28.8 -19.8 235 43 22 8.7 4.8 | -28.9 -20.0 240 48 25 7.9 4.3
28000 -26.2 -15.2 230 41 21 8.3 4.6 | -26.6 -15.9 235 45 23 7.9 4.3
27000 -24.0 -11.2 230 39 20 7.4 4.1 | -24.2 -11.6 235 43 22 7.8 4.3
26000 -21.2 -6.2 230 37 19 7.4 4.1 | -21.2 -6.2 235 40 21 7.8 4.3
25000 -18.9 -2.0 225 35 18 7.2 4.0 | -18.9 -2.0 235 38 20 7.5 4.1
24000 -16.9 1.6 225 33 17 6.7 3.7 | -16.9 1.6 235 36 18 6.4 3.5
23000 -14.9 5.2 225 31 16 6.7 3.7 | -15.0 5.0 235 34 17 6.4 3.5
22000 -12.9 8.8 225 30 15 6.2 3.4 | -13.1 8.4 235 31 16 6.2 3.4
21000 -11.3 11.7 230 27 14 5.4 3.0 | -11.4 11.5 230 29 15 5.9 3.3
20000 -9.7 14.5 230 25 13 5.5 3.0 | -9.6 14.7 230 26 13 6.0 3.3
19500 -8.9 16.0 230 24 12 5.5 3.0 | -8.8 16.2 225 24 12 6.0 3.3
19000 -8.1 17.4 230 23 12 5.7 3.1 | -7.9 17.8 225 23 12 6.0 3.3
18500 -7.3 18.9 230 23 12 5.8 3.2 | -7.1 19.2 220 23 12 6.1 3.3
18000 -6.5 20.3 230 22 11 6.0 3.3 | -6.2 20.8 220 22 12 6.1 3.3
17500 -5.7 21.7 225 22 11 6.3 3.4 | -5.4 22.3 220 23 12 6.1 3.3
17000 -4.8 23.4 225 22 11 6.3 3.5 | -4.5 23.9 220 23 12 6.1 3.3
16500 -3.9 25.0 220 21 11 6.6 3.6 | -3.6 25.5 220 23 12 7.0 3.9
16000 -3.0 26.6 220 21 11 6.6 3.6 | -2.6 27.3 220 23 12 7.0 3.8
15500 -2.0 28.4 215 20 10 7.0 3.9 | -1.6 29.1 220 23 12 7.4 4.1
15000 -1.0 30.2 215 20 10 7.2 3.9 | -0.5 31.1 220 23 12 7.6 4.2
14500 0.0 32.0 215 19 10 7.3 4.0 | 0.6 33.1 215 23 12 7.8 4.3
14000 1.1 34.0 215 19 10 7.4 4.1 | 1.7 35.1 215 22 11 8.0 4.4
13500 2.2 36.0 215 18 9 7.5 4.1 | 2.9 37.2 215 21 11 8.1 4.4
13000 3.3 37.9 215 17 9 7.8 4.3 | 4.0 39.2 215 20 10 8.2 4.5
12500 4.4 39.9 215 16 8 7.8 4.3 | 5.2 41.4 220 19 10 8.2 4.5
12000 5.5 41.9 215 15 7 8.2 4.5 | 6.4 43.5 220 18 9 8.8 4.8
11500 6.7 44.1 215 13 7 8.2 4.5 | 7.7 45.9 220 17 9 8.7 4.8
11000 7.9 46.2 220 12 6 8.2 4.5 | 9.0 48.2 220 15 8 9.0 4.9
10500 9.1 48.4 220 10 5 6.9 3.8 | 10.3 50.5 220 14 7 7.5 4.1
10250 9.5 49.1 225 9 5 6.4 3.5 | 10.8 51.4 220 14 7 7.9 4.3
10000 10.0 50.0 225 9 5 8.6 4.7 | 11.5 52.7 220 13 7 10.1 5.5
9750 10.7 51.3 225 8 4 9.0 4.9 | 12.2 54.0 220 12 6 9.5 5.2
9500 11.3 52.3 230 8 4 8.6 4.7 | 12.9 55.2 225 11 6 9.7 5.3
9250 11.9 53.4 235 7 3 6.8 3.7 | 13.6 56.5 225 10 5 8.9 4.9
9000 12.3 54.1 240 6 3 7.8 4.3 | 14.2 57.6 225 9 5 8.4 4.6
8750 13.7 56.7 250 6 3 8.8 4.8 | 14.8 58.6 225 8 4 8.6 4.7
8500 14.3 57.7 255 5 3 6.8 3.7 | 16.0 60.8 230 6 3 6.1 3.3
8250 14.7 58.5 265 4 2 8.1 4.4 | 16.4 61.5 235 5 3 7.1 3.9
8000 15.5 59.9 270 4 2 11.9 6.5 | 17.1 62.8 240 4 2 10.4 5.7
7750 16.3 61.3 270 5 3 10.0 5.5 | 17.8 64.0 240 4 2 9.1 5.0
7500 16.9 62.4 275 5 2 6.8 3.7 | 18.4 65.1 245 3 2 6.7 3.7
7250 17.4 63.3 285 5 2 7.7 4.2 | 18.9 66.0 255 2 1 7.1 3.9
7000 18.1 64.6 290 5 2 12.3 6.7 | 19.5 67.1 260 2 1 12.2 6.7
6750 19.1 66.4 280 5 3 11.4 6.2 | 20.5 68.9 260 2 1 11.2 6.2
6500 19.7 67.5 285 5 3 8.4 4.6 | 21.1 70.0 270 2 1 7.8 4.3
6250 20.4 68.7 290 5 3 8.5 4.7 | 21.7 71.1 285 2 1 8.4 4.6
6000 21.1 70.0 295 5 3 12.9 7.1 | 22.4 72.3 300 2 1 10.3 5.7
5750 22.4 72.3 290 5 3 23.4 12.8 | 23.3 73.9 285 1 1 15.6 8.6
5500 23.8 74.8 295 5 3 7.2 3.9 | 24.3 75.7 305 2 1 9.0 4.9
5250 M M M M M M M | M M M M M M M
5000 M M M M M M M | M M M M M M M
________________________________________________________________________________
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 AT WALKER FIELD IN GRAND
JUNCTION, COLORADO AT
NORTH LATITUDE: 39 DEG 07 MIN 00.001 SEC
WEST LONGITUDE: 108 DEG 31 MIN 59.998 SEC
ELEVATION: 4839 FEET (1475 METERS)
AND MAY NOT BE REPRESENTATIVE OF OTHER AREAS ALONG THE WESTERN SLOPE OF
COLORADO. 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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