613
UXUS97 KGJT 081306
SRGGJT
SOARING FORECAST
NATIONAL WEATHER SERVICE GRAND JUNCTION, COLORADO
706 AM MDT TUESDAY, SEPTEMBER 8, 2026
THIS FORECAST IS FOR TUESDAY, SEPTEMBER 8, 2026:
IF THE TRIGGER TEMPERATURE OF 78.5 F/25.8 C IS REACHED...THEN
THERMAL SOARING INDEX....................... EXCELLENT
MAXIMUM RATE OF LIFT........................ 985 FT/MIN (5.0 M/S)
MAXIMUM HEIGHT OF THERMALS.................. 16943 FT MSL (11334 FT AGL)
FORECAST MAXIMUM TEMPERATURE................... 90.0 F/32.7 C
TIME OF TRIGGER TEMPERATURE.................... 1045 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................. 13896 FT MSL (8287 FT AGL)
THERMAL SOARING OUTLOOK FOR WEDNESDAY 09/09.... EXCELLENT
WAVE SOARING INDEX............................. NOT AVAILABLE
REMARKS...
SUNRISE/SUNSET.................... 06:49:33 / 19:33:55 MDT
TOTAL POSSIBLE SUNSHINE........... 12 HR 44 MIN 22 SEC (764 MIN 22 SEC)
ALTITUDE OF SUN AT 13:11:44 MDT... 56.24 DEGREES
UPPER AIR DATA FROM RAWINSONDE OBSERVATION TAKEN ON 09/08/2026 AT 0600 MDT
FREEZING LEVEL.................. 15836 FT MSL (10227 FT AGL)
CONVECTIVE CONDENSATION LEVEL... 21299 FT MSL (15690 FT AGL)
LIFTED CONDENSATION LEVEL....... 19324 FT MSL (13715 FT AGL)
LIFTED INDEX.................... +3.5
K INDEX......................... +4.3
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 -65.9 -86.6 255 43 22 3.2 1.8 M M M M M
45000 -59.4 -74.9 255 54 28 6.2 3.4 M M M M M
40000 -49.2 -56.6 260 57 30 7.4 4.1 M M M M M
38000 -44.8 -48.6 260 56 29 7.4 4.1 M M M M M
36000 -40.3 -40.5 265 54 28 6.8 3.7 M M M M M
34000 -36.3 -33.3 260 48 25 6.7 3.7 M M M M M
32000 -32.3 -26.1 260 42 21 7.4 4.1 M M M M M
30000 -28.1 -18.6 260 39 20 7.0 3.9 47.5 117.6 11.6 M M
29000 -26.0 -14.8 265 37 19 7.1 3.9 46.6 115.8 11.0 M M
28000 -23.8 -10.8 265 36 19 7.9 4.4 45.7 114.2 10.4 M M
27000 -21.5 -6.7 265 36 19 7.8 4.3 44.8 112.7 9.8 M M
26000 -19.1 -2.4 260 36 19 7.8 4.3 44.1 111.5 9.4 M M
25000 -16.7 1.9 260 36 19 7.0 3.9 43.6 110.4 9.0 M M
24000 -14.8 5.4 265 34 18 6.2 3.4 42.1 107.9 8.0 M M
23000 -12.9 8.8 265 32 17 6.3 3.4 40.9 105.6 7.1 M M
22000 -10.6 12.9 265 29 15 5.5 3.0 39.3 102.8 5.9 M M
21000 -8.9 16.0 265 26 13 5.6 3.1 37.8 100.0 4.7 M M
20000 -7.2 19.0 265 22 11 5.6 3.1 36.4 97.5 3.6 M M
19500 -6.4 20.5 265 21 11 5.4 3.0 35.7 96.3 3.0 M M
19000 -5.6 21.9 265 19 10 5.3 2.9 34.9 94.9 2.3 M M
18500 -4.8 23.4 265 18 9 5.3 2.9 34.2 93.5 1.7 M M
18000 -3.9 25.0 260 16 8 6.5 3.6 33.5 92.3 1.1 M M
17500 -3.0 26.6 260 16 8 6.4 3.5 32.9 91.3 0.5 M M
17000 -2.0 28.4 260 15 8 6.3 3.5 32.4 90.3 0.0 M M
16500 -1.1 30.0 260 14 7 6.3 3.4 31.8 89.2 -0.6 944 4.8
16000 -0.2 31.6 260 14 7 6.4 3.5 31.2 88.2 -1.1 902 4.6
15500 0.7 33.3 265 13 7 6.8 3.7 30.7 87.2 -1.7 858 4.4
15000 1.7 35.1 270 13 7 6.7 3.7 30.2 86.3 -2.1 814 4.1
14500 2.8 37.0 270 12 6 7.8 4.3 29.8 85.6 -2.6 767 3.9
14000 3.9 39.0 275 11 6 7.7 4.2 29.4 85.0 -2.9 719 3.7
13500 5.0 41.0 280 10 5 8.1 4.4 29.1 84.4 -3.3 670 3.4
13000 6.2 43.2 280 10 5 8.2 4.5 28.8 83.9 -3.6 621 3.2
12500 7.3 45.1 280 9 4 8.3 4.5 28.6 83.5 -3.9 571 2.9
12000 8.5 47.3 290 7 4 8.3 4.6 28.4 83.1 -4.2 520 2.6
11500 9.7 49.5 295 6 3 7.6 4.2 28.1 82.6 -4.5 470 2.4
11000 10.8 51.4 310 5 3 7.3 4.0 27.7 81.9 -5.0 424 2.2
10500 11.7 53.1 325 4 2 6.5 3.6 27.2 81.0 -5.4 379 1.9
10250 12.3 54.1 330 4 2 7.5 4.1 27.0 80.6 -5.7 356 1.8
10000 12.8 55.0 340 4 2 7.9 4.3 26.9 80.4 -5.8 332 1.7
9750 13.4 56.1 350 4 2 7.8 4.3 26.7 80.1 -6.0 307 1.6
9500 14.0 57.2 360 4 2 6.6 3.6 26.5 79.8 -6.2 283 1.4
9250 14.4 57.9 015 4 2 6.4 3.5 26.3 79.3 -6.5 261 1.3
9000 15.0 59.0 025 5 2 7.3 4.0 26.0 78.9 -6.7 238 1.2
8750 15.5 59.9 030 5 3 6.9 3.8 25.8 78.5 -6.9 214 1.1
8500 16.0 60.8 035 6 3 6.6 3.6 25.6 78.1 -7.1 192 1.0
8250 16.5 61.7 040 7 4 5.9 3.2 25.3 77.6 -7.4 170 0.9
8000 16.9 62.4 045 8 4 5.5 3.0 25.0 77.0 -7.7 150 0.8
7750 17.3 63.1 045 8 4 5.0 2.8 24.7 76.4 -8.1 131 0.7
7500 17.7 63.9 045 8 4 4.5 2.5 24.3 75.7 -8.5 113 0.6
7250 18.0 64.4 045 8 4 4.2 2.3 23.9 75.0 -8.9 96 0.5
7000 18.3 64.9 050 9 4 5.1 2.8 23.5 74.3 -9.3 79 0.4
6750 18.6 65.5 050 9 5 0.8 0.4 23.1 73.5 -9.8 62 0.3
6500 18.4 65.1 050 8 4 -3.9 -2.1 22.1 71.8 -10.8 61 0.3
6250 18.2 64.8 055 8 4 -0.8 -0.5 21.2 70.1 -11.7 60 0.3
6000 18.1 64.6 055 7 4 -4.9 -2.7 20.3 68.6 -12.6 57 0.3
5750 17.0 62.6 060 6 3 -25.6 -14.0 18.6 65.4 -14.5 82 0.4
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 * * * * * *
09/08/2026 AT 0900 MDT | 09/08/2026 AT 1200 MDT
|
CAPE... 0.0 LI... +1.2 | CAPE... 0.0 LI... +1.7
CINH... -0.1 K INDEX... +24.6 | CINH... -0.1 K INDEX... +14.9
|
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 -64.9 -84.8 235 50 26 3.5 1.9 | -65.5 -85.9 240 52 27 3.1 1.7
45000 -57.7 -71.9 235 63 33 7.0 3.8 | -58.5 -73.3 240 63 33 7.4 4.1
40000 -47.5 -53.5 235 72 37 6.1 3.4 | -47.6 -53.7 240 69 36 6.6 3.6
38000 -43.8 -46.8 240 73 38 6.2 3.4 | -43.6 -46.5 240 71 36 6.6 3.6
36000 -39.6 -39.3 240 74 38 5.7 3.1 | -39.2 -38.6 240 72 37 5.7 3.1
34000 -36.6 -33.9 240 68 35 5.1 2.8 | -36.2 -33.2 240 66 34 5.0 2.8
32000 -33.5 -28.3 235 62 32 5.4 3.0 | -33.2 -27.8 240 59 30 5.4 3.0
30000 -29.2 -20.6 235 58 30 7.5 4.1 | -29.0 -20.2 240 55 29 7.2 4.0
29000 -27.0 -16.6 235 56 29 7.5 4.1 | -26.8 -16.2 235 54 28 7.2 4.0
28000 -24.8 -12.6 230 53 27 6.7 3.7 | -24.7 -12.5 235 52 27 6.6 3.6
27000 -22.9 -9.2 235 50 26 6.5 3.6 | -22.7 -8.9 235 49 25 6.5 3.6
26000 -20.9 -5.6 235 46 24 6.5 3.6 | -20.8 -5.4 235 46 23 6.6 3.6
25000 -19.0 -2.2 240 43 22 6.5 3.6 | -18.8 -1.8 240 42 22 6.6 3.6
24000 -17.0 1.4 240 39 20 6.7 3.7 | -16.7 1.9 240 39 20 7.0 3.9
23000 -15.0 5.0 235 36 18 6.7 3.7 | -14.1 6.6 235 34 18 7.0 3.9
22000 -12.5 9.5 235 32 16 6.4 3.5 | -12.0 10.4 235 31 16 6.9 3.8
21000 -10.6 12.9 235 31 16 6.4 3.5 | -9.9 14.2 235 29 15 6.9 3.8
20000 -8.8 16.2 230 30 15 6.4 3.5 | -7.8 18.0 235 27 14 6.9 3.8
19500 -7.9 17.8 230 30 15 6.2 3.4 | -6.8 19.8 235 26 13 6.7 3.7
19000 -7.1 19.2 230 30 15 5.5 3.0 | -5.8 21.6 240 26 13 6.4 3.5
18500 -6.3 20.7 230 29 15 5.6 3.1 | -4.9 23.2 240 25 13 6.5 3.6
18000 -5.5 22.1 230 29 15 6.3 3.4 | -3.9 25.0 240 25 13 5.7 3.1
17500 -4.6 23.7 230 29 15 6.4 3.5 | -3.1 26.4 240 25 13 5.7 3.1
17000 -3.7 25.3 230 29 15 6.4 3.5 | -2.3 27.9 240 25 13 5.6 3.1
16500 -2.8 27.0 230 28 15 6.1 3.3 | -1.6 29.1 240 25 13 5.3 2.9
16000 -1.9 28.6 230 28 14 6.0 3.3 | -0.8 30.6 240 25 13 5.4 2.9
15500 -1.0 30.2 230 27 14 6.9 3.8 | -0.1 31.8 235 24 13 6.0 3.3
15000 -0.0 32.0 230 26 13 6.9 3.8 | 0.8 33.4 235 24 12 6.0 3.3
14500 1.0 33.8 230 25 13 7.0 3.8 | 1.6 34.9 235 23 12 6.9 3.8
14000 2.0 35.6 230 24 12 7.1 3.9 | 2.6 36.7 235 22 11 7.2 3.9
13500 3.0 37.4 230 22 12 7.4 4.0 | 3.5 38.3 235 21 11 7.7 4.2
13000 4.2 39.6 230 21 11 7.7 4.2 | 4.7 40.5 230 20 10 8.1 4.5
12500 5.3 41.5 230 19 10 7.9 4.3 | 5.8 42.4 230 18 9 8.4 4.6
12000 6.5 43.7 230 17 9 8.1 4.5 | 7.0 44.6 230 17 9 8.7 4.8
11500 7.7 45.9 230 15 8 8.2 4.5 | 8.3 46.9 230 15 8 8.7 4.8
11000 8.9 48.0 230 13 7 8.2 4.5 | 9.6 49.3 225 14 7 8.6 4.7
10500 10.2 50.4 225 11 6 7.0 3.8 | 10.9 51.6 225 12 6 6.5 3.6
10250 10.6 51.1 225 11 5 6.7 3.7 | 11.3 52.3 230 11 6 7.1 3.9
10000 11.2 52.2 220 10 5 8.5 4.7 | 12.0 53.6 230 11 6 10.4 5.7
9750 11.9 53.4 215 9 5 8.4 4.6 | 12.7 54.9 230 10 5 9.7 5.3
9500 12.5 54.5 210 9 4 8.6 4.7 | 13.4 56.1 230 9 5 9.3 5.1
9250 13.1 55.6 205 8 4 8.9 4.9 | 14.1 57.4 230 8 4 8.4 4.6
9000 13.8 56.8 205 7 4 7.6 4.2 | 14.7 58.5 230 7 4 8.8 4.8
8750 14.3 57.7 195 7 4 6.4 3.5 | 15.4 59.7 230 7 4 9.3 5.1
8500 14.8 58.6 190 7 4 7.0 3.8 | 16.1 61.0 230 7 3 8.5 4.6
8250 15.9 60.6 180 7 3 7.1 3.9 | 17.2 63.0 240 4 2 8.7 4.8
8000 16.4 61.5 175 6 3 6.7 3.7 | 18.0 64.4 235 4 2 10.9 6.0
7750 16.8 62.2 170 6 3 6.0 3.3 | 18.8 65.8 235 5 2 9.4 5.2
7500 17.2 63.0 165 6 3 5.5 3.0 | 19.4 66.9 240 4 2 8.0 4.4
7250 17.6 63.7 165 6 3 5.7 3.2 | 20.0 68.0 250 4 2 9.4 5.2
7000 18.0 64.4 160 6 3 5.4 3.0 | 20.8 69.4 245 4 2 11.9 6.5
6750 18.4 65.1 150 5 3 4.5 2.5 | 21.7 71.1 240 4 2 10.8 5.9
6500 18.7 65.7 140 5 3 3.6 2.0 | 22.4 72.3 250 3 2 9.6 5.3
6250 19.0 66.2 135 5 3 5.4 3.0 | 23.2 73.8 260 3 2 9.1 5.0
6000 19.5 67.1 125 4 2 8.1 4.5 | 23.9 75.0 250 3 2 15.1 8.3
5750 20.1 68.2 115 4 2 7.4 4.1 | 25.6 78.1 260 3 2 28.3 15.5
5500 20.5 68.9 100 4 2 7.4 4.1 | 27.2 81.0 275 3 1 4.9 2.7
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
09/08/2026 AT 1500 MDT | 09/08/2026 AT 1800 MDT
|
CAPE... +7.7 LI... +1.9 | CAPE... 0.0 LI... +2.1
CINH... -28.7 K INDEX... +18.0 | CINH... -0.1 K INDEX... +15.8
|
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 -65.4 -85.7 240 49 25 2.2 1.2 | -65.2 -85.4 245 49 25 2.5 1.4
45000 -59.0 -74.2 240 62 32 7.7 4.2 | -58.9 -74.0 245 61 32 7.1 3.9
40000 -47.8 -54.0 240 69 35 6.5 3.5 | -48.3 -54.9 245 66 34 6.8 3.7
38000 -43.5 -46.3 245 70 36 6.5 3.5 | -43.7 -46.7 250 68 35 6.8 3.7
36000 -39.6 -39.3 245 72 37 5.8 3.2 | -39.6 -39.3 250 70 36 5.8 3.2
34000 -36.3 -33.3 245 66 34 5.4 3.0 | -36.4 -33.5 250 63 32 5.4 3.0
32000 -33.1 -27.6 245 59 31 6.0 3.3 | -33.1 -27.6 255 56 29 6.1 3.4
30000 -28.8 -19.8 245 54 28 7.3 4.0 | -28.6 -19.5 250 51 26 7.7 4.2
29000 -26.6 -15.9 240 52 27 7.3 4.0 | -26.3 -15.3 250 49 25 7.7 4.2
28000 -24.4 -11.9 240 50 26 6.6 3.6 | -24.0 -11.2 250 47 24 6.4 3.5
27000 -22.5 -8.5 240 47 24 6.5 3.6 | -22.1 -7.8 250 45 23 6.4 3.5
26000 -20.5 -4.9 240 44 23 6.5 3.6 | -20.2 -4.4 250 43 22 6.4 3.5
25000 -18.5 -1.3 240 41 21 6.6 3.6 | -18.3 -0.9 245 41 21 6.4 3.5
24000 -16.5 2.3 240 38 19 6.7 3.7 | -15.9 3.4 245 37 19 6.5 3.5
23000 -14.0 6.8 240 34 17 6.7 3.7 | -14.0 6.8 245 34 17 6.5 3.6
22000 -12.0 10.4 240 31 16 7.1 3.9 | -12.1 10.2 245 31 16 6.7 3.7
21000 -9.9 14.2 240 29 15 7.1 3.9 | -10.1 13.8 245 28 15 6.7 3.7
20000 -7.8 18.0 240 28 14 7.1 3.9 | -8.0 17.6 245 26 13 6.7 3.7
19500 -6.7 19.9 240 27 14 6.8 3.8 | -7.0 19.4 245 24 13 6.8 3.7
19000 -5.7 21.7 240 26 13 6.5 3.6 | -6.0 21.2 245 23 12 6.9 3.8
18500 -4.7 23.5 240 25 13 6.6 3.6 | -5.0 23.0 245 22 12 6.9 3.8
18000 -3.8 25.2 240 25 13 5.8 3.2 | -4.0 24.8 245 21 11 7.1 3.9
17500 -3.0 26.6 235 24 12 6.0 3.3 | -2.9 26.8 240 21 11 7.1 3.9
17000 -2.2 28.0 235 23 12 6.2 3.4 | -1.9 28.6 240 20 10 7.2 3.9
16500 -1.3 29.7 235 22 11 6.5 3.6 | -0.9 30.4 240 19 10 7.3 4.0
16000 -0.3 31.5 230 21 11 6.6 3.6 | 0.2 32.4 235 18 9 7.5 4.1
15500 0.6 33.1 230 20 11 7.4 4.1 | 1.3 34.3 235 17 9 8.0 4.4
15000 1.6 34.9 230 19 10 7.4 4.1 | 2.4 36.3 230 16 8 8.0 4.4
14500 2.7 36.9 230 18 9 7.8 4.3 | 3.5 38.3 230 15 8 8.4 4.6
14000 3.8 38.8 230 17 9 7.9 4.3 | 4.8 40.6 230 14 7 8.5 4.7
13500 4.9 40.8 230 16 8 8.5 4.7 | 6.0 42.8 230 13 7 8.6 4.7
13000 6.2 43.2 230 15 8 8.9 4.9 | 7.3 45.1 230 12 6 8.7 4.8
12500 7.5 45.5 230 14 7 8.9 4.9 | 8.6 47.5 235 12 6 8.7 4.8
12000 8.8 47.8 235 13 7 9.0 4.9 | 9.9 49.8 240 11 6 8.6 4.7
11500 10.2 50.4 235 13 6 8.9 4.9 | 11.1 52.0 245 11 6 8.6 4.7
11000 11.4 52.5 240 12 6 8.6 4.7 | 12.4 54.3 250 11 5 8.4 4.6
10500 12.7 54.9 245 11 6 7.2 4.0 | 13.7 56.7 255 10 5 7.3 4.0
10250 13.2 55.8 245 11 6 7.6 4.2 | 14.2 57.6 255 11 6 7.7 4.2
10000 13.9 57.0 250 10 5 9.8 5.4 | 14.9 58.8 260 11 6 9.5 5.2
9750 14.6 58.3 255 10 5 9.3 5.1 | 15.5 59.9 265 11 5 9.0 4.9
9500 15.3 59.5 255 10 5 9.2 5.1 | 16.2 61.2 265 10 5 9.3 5.1
9250 16.0 60.8 260 9 5 8.9 4.9 | 16.9 62.4 270 11 5 9.2 5.1
9000 16.6 61.9 265 9 5 8.9 4.9 | 17.6 63.7 270 11 6 8.6 4.7
8750 17.3 63.1 265 9 5 9.1 5.0 | 18.8 65.8 275 10 5 8.1 4.4
8500 17.9 64.2 270 9 5 8.7 4.8 | 19.4 66.9 280 10 5 6.8 3.7
8250 19.2 66.6 275 10 5 9.6 5.2 | 19.9 67.8 280 10 5 8.5 4.7
8000 20.0 68.0 275 9 5 12.2 6.7 | 20.7 69.3 280 10 5 10.7 5.9
7750 20.8 69.4 275 9 5 9.7 5.3 | 21.4 70.5 280 10 5 9.0 5.0
7500 21.4 70.5 280 10 5 7.4 4.1 | 22.0 71.6 285 10 5 7.5 4.1
7250 22.1 71.8 280 10 5 9.3 5.1 | 22.6 72.7 285 11 5 8.8 4.9
7000 22.9 73.2 280 10 5 12.5 6.8 | 23.4 74.1 285 10 5 11.4 6.2
6750 23.8 74.8 280 9 5 11.6 6.3 | 24.2 75.6 285 10 5 10.9 6.0
6500 24.6 76.3 285 9 5 10.4 5.7 | 25.0 77.0 285 10 5 9.8 5.4
6250 25.4 77.7 285 10 5 9.0 5.0 | 25.7 78.3 290 10 5 9.4 5.1
6000 26.1 79.0 285 9 5 14.5 7.9 | 26.4 79.5 290 10 5 10.7 5.9
5750 27.7 81.9 290 9 5 30.3 16.6 | 27.4 81.3 290 9 4 16.4 9.0
5500 29.7 85.5 295 9 5 9.1 5.0 | 28.6 83.5 290 9 4 11.1 6.1
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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