852
UXUS97 KGJT 151305
SRGGJT
SOARING FORECAST
NATIONAL WEATHER SERVICE GRAND JUNCTION, COLORADO
705 AM MDT MONDAY, SEPTEMBER 15, 2025
THIS FORECAST IS FOR MONDAY, SEPTEMBER 15, 2025:
IF THE TRIGGER TEMPERATURE OF 76.6 F/24.8 C IS REACHED...THEN
THERMAL SOARING INDEX....................... EXCELLENT
MAXIMUM RATE OF LIFT........................ 1453 FT/MIN (7.4 M/S)
MAXIMUM HEIGHT OF THERMALS.................. 20352 FT MSL (14744 FT AGL)
FORECAST MAXIMUM TEMPERATURE................... 84.0 F/29.3 C
TIME OF TRIGGER TEMPERATURE.................... 1145 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................. 11855 FT MSL (6247 FT AGL)
THERMAL SOARING OUTLOOK FOR TUESDAY 09/16...... EXCELLENT
WAVE SOARING INDEX............................. NOT AVAILABLE
REMARKS...
SUNRISE/SUNSET.................... 06:56:04 / 19:22:17 MDT
TOTAL POSSIBLE SUNSHINE........... 12 HR 26 MIN 13 SEC (746 MIN 13 SEC)
ALTITUDE OF SUN AT 13:09:10 MDT... 53.53 DEGREES
UPPER AIR DATA FROM RAWINSONDE OBSERVATION TAKEN ON 09/15/2025 AT 0600 MDT
FREEZING LEVEL.................. 14371 FT MSL (8763 FT AGL)
CONVECTIVE CONDENSATION LEVEL... 17533 FT MSL (11925 FT AGL)
LIFTED CONDENSATION LEVEL....... 18292 FT MSL (12684 FT AGL)
LIFTED INDEX.................... -2.8
K INDEX......................... +21.6
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 -59.0 -74.2 290 28 14 3.0 1.6 M M M M M
45000 -55.0 -67.0 280 42 22 1.7 0.9 M M M M M
40000 -52.5 -62.5 280 62 32 2.0 1.1 M M M M M
38000 -50.7 -59.3 275 60 31 2.8 1.5 M M M M M
36000 -49.0 -56.2 275 59 30 2.8 1.5 M M M M M
34000 -46.0 -50.8 270 56 29 6.2 3.4 M M M M M
32000 -42.3 -44.1 270 52 27 6.2 3.4 M M M M M
30000 -37.9 -36.2 270 46 24 7.7 4.2 36.3 97.3 5.6 M M
29000 -35.6 -32.1 270 43 22 7.8 4.3 35.5 95.9 5.1 M M
28000 -33.3 -27.9 270 39 20 7.8 4.3 34.9 94.8 4.6 M M
27000 -31.0 -23.8 265 37 19 7.7 4.2 34.0 93.2 4.0 M M
26000 -28.7 -19.7 265 34 18 7.7 4.2 33.2 91.7 3.3 M M
25000 -26.5 -15.7 260 32 16 7.7 4.2 32.5 90.5 2.8 M M
24000 -24.1 -11.4 255 30 15 7.9 4.4 31.8 89.2 2.2 M M
23000 -21.8 -7.2 255 28 15 7.9 4.4 31.1 87.9 1.6 M M
22000 -19.4 -2.9 250 27 14 8.0 4.4 30.5 86.9 1.2 M M
21000 -16.5 2.3 245 24 12 7.8 4.3 29.6 85.3 0.4 M M
20000 -14.2 6.4 240 21 11 7.9 4.3 28.9 84.1 -0.3 1408 7.2
19500 -13.1 8.4 235 20 11 7.9 4.3 28.6 83.5 -0.6 1359 6.9
19000 -11.9 10.6 235 20 10 8.3 4.6 28.4 83.0 -0.9 1309 6.6
18500 -10.7 12.7 230 19 10 8.3 4.5 28.1 82.6 -1.1 1257 6.4
18000 -9.5 14.9 225 18 9 8.3 4.6 27.9 82.1 -1.3 1206 6.1
17500 -8.2 17.2 225 18 9 8.3 4.6 27.6 81.7 -1.6 1154 5.9
17000 -7.0 19.4 225 18 9 8.4 4.6 27.4 81.3 -1.8 1102 5.6
16500 -5.7 21.7 225 18 9 9.0 4.9 27.2 80.9 -2.0 1048 5.3
16000 -4.4 24.1 225 18 9 8.9 4.9 27.0 80.7 -2.1 994 5.0
15500 -3.0 26.6 225 18 9 9.2 5.1 26.9 80.5 -2.3 939 4.8
15000 -1.7 28.9 225 17 9 9.2 5.1 26.8 80.3 -2.4 883 4.5
14500 -0.3 31.5 225 17 9 9.3 5.1 26.8 80.2 -2.5 827 4.2
14000 1.1 34.0 225 17 9 9.3 5.1 26.7 80.0 -2.6 771 3.9
13500 2.5 36.5 230 16 8 9.3 5.1 26.6 79.9 -2.6 715 3.6
13000 3.9 39.0 230 16 8 9.3 5.1 26.5 79.7 -2.7 658 3.3
12500 5.2 41.4 230 16 8 9.2 5.1 26.5 79.6 -2.8 602 3.1
12000 6.6 43.9 230 16 8 9.0 4.9 26.3 79.4 -3.0 546 2.8
11500 7.9 46.2 230 16 8 8.9 4.9 26.2 79.2 -3.1 491 2.5
11000 9.2 48.6 230 16 8 8.0 4.4 26.0 78.8 -3.3 440 2.2
10500 10.3 50.5 225 15 8 10.3 5.7 25.7 78.2 -3.7 390 2.0
10250 11.2 52.2 225 15 8 10.3 5.7 25.8 78.5 -3.5 357 1.8
10000 11.8 53.2 220 15 8 7.1 3.9 25.7 78.2 -3.7 332 1.7
9750 12.4 54.3 220 15 8 8.2 4.5 25.5 78.0 -3.8 307 1.6
9500 12.9 55.2 215 14 7 6.8 3.8 25.4 77.7 -4.0 282 1.4
9250 13.4 56.1 215 14 7 6.9 3.8 25.1 77.2 -4.3 261 1.3
9000 14.0 57.2 210 13 7 8.0 4.4 25.0 77.0 -4.4 236 1.2
8750 14.6 58.3 205 13 7 7.9 4.3 24.8 76.7 -4.6 211 1.1
8500 15.1 59.2 200 12 6 7.0 3.9 24.7 76.4 -4.8 187 0.9
8250 15.6 60.1 195 12 6 5.4 3.0 24.4 75.9 -5.0 166 0.8
8000 16.0 60.8 190 12 6 5.2 2.8 24.0 75.3 -5.4 147 0.7
7750 16.4 61.5 185 11 6 5.6 3.1 23.7 74.7 -5.8 128 0.6
7500 16.8 62.2 180 11 5 4.3 2.4 23.4 74.1 -6.1 109 0.6
7250 17.0 62.6 170 11 6 2.8 1.5 22.9 73.2 -6.6 94 0.5
7000 17.2 63.0 165 11 6 2.8 1.5 22.3 72.2 -7.2 81 0.4
6750 17.4 63.3 160 11 6 1.5 0.9 21.8 71.2 -7.7 68 0.3
6500 17.4 63.3 155 11 5 -2.3 -1.3 21.0 69.9 -8.5 61 0.3
6250 17.0 62.6 145 10 5 -6.5 -3.6 19.9 67.9 -9.6 65 0.3
6000 16.7 62.1 140 9 4 2.1 1.2 18.9 66.0 -10.7 67 0.3
5750 16.9 62.4 130 8 4 -2.5 -1.3 18.5 65.2 -11.2 52 0.3
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 * * * * * *
09/15/2025 AT 0900 MDT | 09/15/2025 AT 1200 MDT
|
CAPE... 0.0 LI... +1.9 | CAPE... +38.0 LI... +1.6
CINH... -0.1 K INDEX... +20.8 | CINH... -35.6 K INDEX... +20.5
|
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 -59.5 -75.1 270 17 9 3.5 1.9 | -59.2 -74.6 275 23 12 3.3 1.8
45000 -54.6 -66.3 270 28 14 2.5 1.4 | -54.9 -66.8 275 35 18 1.7 0.9
40000 -50.9 -59.6 270 42 22 2.3 1.2 | -52.4 -62.3 280 46 24 1.9 1.0
38000 -49.6 -57.3 270 48 25 1.8 1.0 | -50.8 -59.4 270 50 26 2.3 1.3
36000 -48.5 -55.3 265 54 28 1.8 1.0 | -49.4 -56.9 265 54 28 2.4 1.3
34000 -45.8 -50.4 270 52 27 6.0 3.3 | -46.3 -51.3 265 51 26 6.6 3.6
32000 -42.2 -44.0 270 46 23 6.0 3.3 | -42.4 -44.3 270 43 22 6.6 3.6
30000 -37.8 -36.0 275 41 21 8.1 4.4 | -37.8 -36.0 270 38 19 8.1 4.4
29000 -35.4 -31.7 275 39 20 8.1 4.4 | -35.4 -31.7 270 36 18 8.1 4.4
28000 -33.0 -27.4 280 37 19 8.0 4.4 | -33.0 -27.4 270 34 17 8.1 4.4
27000 -30.5 -22.9 280 35 18 8.5 4.6 | -30.5 -22.9 270 32 16 8.4 4.6
26000 -28.0 -18.4 280 33 17 8.5 4.6 | -28.0 -18.4 270 29 15 8.4 4.6
25000 -25.4 -13.7 275 31 16 8.5 4.6 | -25.4 -13.7 270 27 14 8.4 4.6
24000 -23.0 -9.4 275 30 15 8.0 4.4 | -22.9 -9.2 265 26 13 8.4 4.6
23000 -20.0 -4.0 270 28 14 8.0 4.4 | -19.8 -3.6 265 26 13 8.4 4.6
22000 -17.6 0.3 265 27 14 7.9 4.4 | -17.3 0.9 265 26 13 8.2 4.5
21000 -15.3 4.5 260 25 13 7.5 4.1 | -14.9 5.2 260 25 13 7.8 4.3
20000 -13.1 8.4 260 24 12 7.5 4.1 | -12.6 9.3 260 24 13 7.8 4.3
19500 -12.0 10.4 260 23 12 7.7 4.2 | -11.5 11.3 260 24 12 7.9 4.3
19000 -11.0 12.2 260 22 11 5.8 3.2 | -10.4 13.3 255 23 12 6.4 3.5
18500 -10.1 13.8 260 21 11 6.0 3.3 | -9.5 14.9 255 22 12 6.5 3.6
18000 -9.3 15.3 260 20 10 6.2 3.4 | -8.5 16.7 250 22 11 6.4 3.5
17500 -8.4 16.9 255 18 9 6.5 3.6 | -7.6 18.3 245 21 11 6.2 3.4
17000 -7.4 18.7 255 17 9 6.5 3.5 | -6.7 19.9 245 20 10 6.3 3.4
16500 -6.4 20.5 255 16 8 7.5 4.1 | -5.8 21.6 240 19 10 6.6 3.6
16000 -5.4 22.3 250 15 8 7.4 4.1 | -4.9 23.2 240 18 9 6.6 3.6
15500 -4.3 24.3 250 14 7 8.2 4.5 | -3.9 25.0 235 17 9 7.6 4.2
15000 -3.0 26.6 245 14 7 8.5 4.6 | -2.8 27.0 235 17 9 7.9 4.3
14500 -1.8 28.8 245 14 7 8.5 4.7 | -1.6 29.1 230 17 9 8.2 4.5
14000 -0.5 31.1 245 14 7 8.5 4.6 | -0.4 31.3 230 16 8 8.6 4.7
13500 0.7 33.3 240 14 7 8.4 4.6 | 0.9 33.6 230 16 8 8.7 4.7
13000 2.0 35.6 240 14 7 8.3 4.6 | 2.2 36.0 230 16 8 8.6 4.7
12500 3.2 37.8 240 14 7 8.3 4.6 | 3.5 38.3 230 15 8 8.6 4.7
12000 4.4 39.9 240 14 7 8.3 4.6 | 4.7 40.5 230 15 8 8.7 4.8
11500 5.7 42.3 235 13 7 8.3 4.6 | 6.0 42.8 230 14 7 8.7 4.8
11000 6.9 44.4 235 12 6 8.4 4.6 | 7.3 45.1 225 14 7 8.8 4.8
10500 8.2 46.8 230 12 6 8.0 4.4 | 8.6 47.5 225 13 7 7.3 4.0
10250 8.7 47.7 230 11 6 6.1 3.3 | 9.1 48.4 225 13 6 6.5 3.6
10000 9.1 48.4 225 11 6 7.5 4.1 | 9.7 49.5 225 12 6 9.2 5.1
9750 9.8 49.6 225 10 5 9.3 5.1 | 10.4 50.7 225 11 6 9.9 5.4
9500 10.5 50.9 220 10 5 8.7 4.8 | 11.1 52.0 220 11 6 9.6 5.2
9250 11.1 52.0 215 10 5 7.7 4.2 | 11.8 53.2 220 10 5 8.1 4.5
9000 11.6 52.9 210 10 5 6.7 3.7 | 12.3 54.1 220 9 5 7.8 4.3
8750 12.1 53.8 200 10 5 6.8 3.7 | 13.0 55.4 215 9 5 8.7 4.8
8500 12.6 54.7 195 10 5 6.4 3.5 | 14.1 57.4 205 8 4 6.6 3.6
8250 13.4 56.1 180 11 6 4.8 2.6 | 14.6 58.3 200 7 4 7.3 4.0
8000 13.7 56.7 175 11 6 4.9 2.7 | 15.3 59.5 200 7 4 9.6 5.3
7750 14.1 57.4 170 11 6 4.2 2.3 | 16.0 60.8 195 7 4 8.9 4.9
7500 14.3 57.7 165 12 6 3.4 1.9 | 16.6 61.9 190 7 3 7.6 4.2
7250 14.6 58.3 160 12 6 3.5 1.9 | 17.1 62.8 185 6 3 8.2 4.5
7000 14.8 58.6 160 12 6 4.0 2.2 | 17.8 64.0 185 6 3 11.3 6.2
6750 15.1 59.2 155 10 5 3.0 1.7 | 18.7 65.7 185 6 3 11.4 6.2
6500 15.2 59.4 150 10 5 2.0 1.1 | 19.5 67.1 180 6 3 10.1 5.5
6250 15.4 59.7 145 10 5 2.1 1.1 | 20.2 68.4 175 5 3 9.4 5.1
6000 15.6 60.1 145 9 5 4.2 2.3 | 21.0 69.8 175 5 3 13.0 7.1
5750 16.0 60.8 130 6 3 8.3 4.6 | 22.3 72.1 175 5 2 24.6 13.5
5500 16.4 61.5 115 5 3 -3.0 -1.6 | 24.1 75.4 170 4 2 16.4 9.0
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
09/15/2025 AT 1500 MDT | 09/15/2025 AT 1800 MDT
|
CAPE... +89.9 LI... +0.8 | CAPE... +57.9 LI... +0.4
CINH... -70.2 K INDEX... +22.7 | CINH... -100.4 K INDEX... +24.0
|
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 -59.1 -74.4 275 26 13 2.9 1.6 | -59.5 -75.1 280 25 13 2.8 1.5
45000 -55.3 -67.5 275 42 22 1.3 0.7 | -55.9 -68.6 275 41 21 0.8 0.4
40000 -53.3 -63.9 280 52 27 1.7 0.9 | -54.7 -66.5 270 50 26 1.6 0.9
38000 -51.6 -60.9 270 53 27 2.6 1.4 | -52.4 -62.3 270 51 26 3.5 1.9
36000 -50.1 -58.2 265 54 28 2.7 1.5 | -50.3 -58.5 265 51 26 3.6 2.0
34000 -46.5 -51.7 265 49 25 7.5 4.1 | -46.5 -51.7 265 46 24 7.6 4.2
32000 -41.9 -43.4 265 40 20 7.6 4.2 | -41.9 -43.4 260 38 20 7.6 4.2
30000 -37.4 -35.3 265 34 17 7.6 4.2 | -37.3 -35.1 260 33 17 7.9 4.3
29000 -35.1 -31.2 265 32 17 7.6 4.2 | -34.9 -30.8 255 31 16 7.9 4.3
28000 -32.8 -27.0 260 30 16 7.6 4.2 | -32.6 -26.7 255 30 15 7.9 4.3
27000 -30.4 -22.7 260 29 15 8.4 4.6 | -30.2 -22.4 255 28 14 7.9 4.3
26000 -27.9 -18.2 260 27 14 8.4 4.6 | -27.9 -18.2 255 25 13 7.9 4.3
25000 -25.3 -13.5 260 25 13 8.4 4.6 | -25.5 -13.9 260 23 12 7.9 4.3
24000 -22.8 -9.0 260 24 12 8.5 4.7 | -23.0 -9.4 260 22 11 8.8 4.8
23000 -19.6 -3.3 260 23 12 8.5 4.7 | -19.7 -3.5 260 21 11 8.8 4.8
22000 -17.1 1.2 255 22 11 8.3 4.6 | -17.1 1.2 260 20 10 8.5 4.7
21000 -14.7 5.5 255 22 11 7.8 4.3 | -14.7 5.5 260 20 10 7.8 4.3
20000 -12.4 9.7 255 22 11 7.9 4.3 | -12.4 9.7 255 19 10 7.8 4.3
19500 -11.2 11.8 255 21 11 8.0 4.4 | -11.2 11.8 255 19 10 7.9 4.3
19000 -10.1 13.8 255 21 11 6.9 3.8 | -10.1 13.8 255 19 10 7.2 3.9
18500 -9.1 15.6 255 21 11 7.0 3.8 | -9.0 15.8 250 18 9 7.3 4.0
18000 -8.1 17.4 250 21 11 7.0 3.8 | -8.0 17.6 250 18 9 7.4 4.0
17500 -7.1 19.2 245 20 10 6.9 3.8 | -6.9 19.6 245 18 9 7.5 4.1
17000 -6.1 21.0 240 20 10 7.0 3.8 | -5.8 21.6 240 18 9 7.6 4.2
16500 -5.1 22.8 235 19 10 7.5 4.1 | -4.8 23.4 235 18 9 7.8 4.3
16000 -4.0 24.8 230 19 10 7.5 4.1 | -3.7 25.3 230 17 9 7.8 4.3
15500 -3.0 26.6 225 18 9 8.0 4.4 | -2.6 27.3 225 17 9 8.6 4.7
15000 -1.8 28.8 225 17 9 8.2 4.5 | -1.3 29.7 220 16 8 8.8 4.8
14500 -0.6 30.9 220 16 8 8.4 4.6 | -0.0 32.0 220 15 8 9.0 4.9
14000 0.7 33.3 220 15 8 8.7 4.8 | 1.3 34.3 215 15 8 9.1 5.0
13500 1.9 35.4 220 15 8 8.8 4.8 | 2.7 36.9 215 14 7 9.1 5.0
13000 3.3 37.9 220 14 7 8.8 4.8 | 4.0 39.2 215 13 7 9.1 5.0
12500 4.6 40.3 220 13 7 8.8 4.8 | 5.4 41.7 220 12 6 9.1 5.0
12000 5.9 42.6 220 12 6 9.1 5.0 | 6.7 44.1 220 12 6 9.0 4.9
11500 7.2 45.0 225 12 6 9.1 5.0 | 8.1 46.6 225 11 6 9.0 4.9
11000 8.6 47.5 230 11 6 8.5 4.6 | 9.4 48.9 225 10 5 8.6 4.7
10500 9.9 49.8 230 10 5 6.8 3.7 | 10.7 51.3 230 10 5 7.0 3.9
10250 10.3 50.5 235 9 5 7.4 4.1 | 11.2 52.2 235 8 4 7.3 4.0
10000 11.0 51.8 235 9 5 10.3 5.6 | 11.9 53.4 235 8 4 9.8 5.3
9750 11.7 53.1 240 9 4 9.5 5.2 | 12.5 54.5 240 8 4 9.1 5.0
9500 12.5 54.5 240 9 4 9.7 5.3 | 13.2 55.8 240 8 4 9.3 5.1
9250 13.2 55.8 245 8 4 9.0 4.9 | 13.9 57.0 245 8 4 9.4 5.2
9000 13.8 56.8 255 7 4 8.9 4.9 | 14.6 58.3 255 7 4 8.8 4.8
8750 14.5 58.1 255 7 4 9.3 5.1 | 15.3 59.5 255 7 4 8.4 4.6
8500 15.8 60.4 255 7 4 8.0 4.4 | 16.5 61.7 265 7 3 7.6 4.2
8250 16.4 61.5 270 7 3 9.1 5.0 | 17.1 62.8 275 6 3 8.1 4.5
8000 17.2 63.0 265 7 3 11.5 6.3 | 17.7 63.9 275 6 3 9.4 5.2
7750 18.0 64.4 260 7 4 10.2 5.6 | 18.4 65.1 275 6 3 9.0 4.9
7500 18.7 65.7 265 7 4 7.9 4.4 | 19.1 66.4 275 6 3 8.2 4.5
7250 19.3 66.7 275 7 3 8.4 4.6 | 19.7 67.5 285 6 3 8.5 4.7
7000 20.0 68.0 275 7 3 12.3 6.7 | 20.4 68.7 285 6 3 10.7 5.9
6750 21.0 69.8 265 7 4 11.9 6.5 | 21.2 70.2 280 6 3 10.8 5.9
6500 21.8 71.2 275 7 3 9.9 5.4 | 22.0 71.6 285 6 3 9.8 5.4
6250 22.5 72.5 280 7 3 9.6 5.3 | 22.7 72.9 290 6 3 9.8 5.4
6000 23.3 73.9 285 7 3 12.3 6.7 | 23.4 74.1 295 6 3 9.2 5.0
5750 24.5 76.1 275 6 3 23.2 12.7 | 24.1 75.4 290 5 3 10.9 6.0
5500 26.4 79.5 290 6 3 25.2 13.8 | 25.2 77.4 305 5 3 20.4 11.2
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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