195
UXUS97 KGJT 211307
SRGGJT
SOARING FORECAST
NATIONAL WEATHER SERVICE GRAND JUNCTION, COLORADO
607 AM MST SATURDAY, FEBRUARY 21, 2026
THIS FORECAST IS FOR SATURDAY, FEBRUARY 21, 2026:
IF THE TRIGGER TEMPERATURE OF 46.8 F/8.2 C IS REACHED...THEN
THERMAL SOARING INDEX....................... POOR
MAXIMUM RATE OF LIFT........................ 179 FT/MIN (0.9 M/S)
MAXIMUM HEIGHT OF THERMALS.................. 7495 FT MSL (1886 FT AGL)
FORECAST MAXIMUM TEMPERATURE................... 38.0 F/3.8 C
TIME OF TRIGGER TEMPERATURE.................... NONE
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................. 6526 FT MSL (917 FT AGL)
THERMAL SOARING OUTLOOK FOR SUNDAY 02/22....... FAIR
WAVE SOARING INDEX............................. NOT AVAILABLE
REMARKS...
SUNRISE/SUNSET.................... 06:57:26 / 17:57:57 MST
TOTAL POSSIBLE SUNSHINE........... 11 HR 0 MIN 31 SEC (660 MIN 31 SEC)
ALTITUDE OF SUN AT 12:27:42 MST... 40.12 DEGREES
UPPER AIR DATA FROM RAWINSONDE OBSERVATION TAKEN ON 02/21/2026 AT 0500 MST
FREEZING LEVEL.................. ENTIRE AIRMASS BELOW 32 F / 0 C
CONVECTIVE CONDENSATION LEVEL... 23211 FT MSL (17602 FT AGL)
LIFTED CONDENSATION LEVEL....... 13957 FT MSL (8347 FT AGL)
LIFTED INDEX.................... +19.3
K INDEX......................... -33.2
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 -63.5 -82.3 280 47 24 0.4 0.2 M M M M M
45000 -62.8 -81.0 285 60 31 1.6 0.9 M M M M M
40000 -60.3 -76.5 280 71 36 1.7 0.9 M M M M M
38000 -57.1 -70.8 280 71 37 6.1 3.3 M M M M M
36000 -53.5 -64.3 280 70 36 6.1 3.3 M M M M M
34000 -49.5 -57.1 280 68 35 7.5 4.1 M M M M M
32000 -45.0 -49.0 280 68 35 7.5 4.1 M M M M M
30000 -40.5 -40.9 280 67 34 7.5 4.1 35.8 96.5 24.4 M M
29000 -38.2 -36.8 285 66 34 7.5 4.1 34.9 94.8 24.0 M M
28000 -36.0 -32.8 285 64 33 7.6 4.1 34.1 93.4 23.7 M M
27000 -33.7 -28.7 285 63 32 7.1 3.9 33.3 91.9 23.4 M M
26000 -31.6 -24.9 285 61 31 7.1 3.9 32.2 89.9 22.8 M M
25000 -29.4 -20.9 285 59 30 7.1 3.9 31.2 88.2 22.3 M M
24000 -27.3 -17.1 285 56 29 6.6 3.6 30.3 86.5 21.8 M M
23000 -25.4 -13.7 285 51 26 6.4 3.5 29.0 84.1 21.0 M M
22000 -23.5 -10.3 285 46 24 6.4 3.5 27.8 82.0 20.2 M M
21000 -21.2 -6.2 280 41 21 5.7 3.1 26.2 79.1 19.1 M M
20000 -19.5 -3.1 280 37 19 5.7 3.1 24.7 76.4 18.1 M M
19500 -18.7 -1.7 280 35 18 5.7 3.1 24.0 75.2 17.6 M M
19000 -17.8 -0.0 280 33 17 5.8 3.2 23.3 74.0 17.1 M M
18500 -16.9 1.6 275 32 16 6.0 3.3 22.7 72.8 16.7 M M
18000 -16.0 3.2 275 30 16 6.1 3.3 22.0 71.6 16.2 M M
17500 -15.1 4.8 270 29 15 6.0 3.3 21.4 70.5 15.8 M M
17000 -14.2 6.4 270 28 14 5.9 3.3 20.7 69.3 15.3 M M
16500 -13.3 8.1 270 26 14 5.3 2.9 20.1 68.2 14.8 M M
16000 -12.6 9.3 265 25 13 4.8 2.6 19.2 66.6 14.1 M M
15500 -11.9 10.6 260 24 12 4.8 2.6 18.4 65.1 13.5 M M
15000 -11.1 12.0 255 23 12 4.8 2.6 17.6 63.6 12.8 M M
14500 -10.4 13.3 250 22 11 4.8 2.6 16.7 62.1 12.1 M M
14000 -9.6 14.7 245 21 11 5.8 3.2 16.0 60.8 11.5 M M
13500 -8.8 16.2 245 21 11 5.8 3.2 15.3 59.6 11.0 M M
13000 -8.0 17.6 240 20 10 4.8 2.6 14.6 58.3 10.4 M M
12500 -7.2 19.0 235 19 10 4.9 2.7 13.8 56.9 9.7 M M
12000 -6.5 20.3 230 17 9 4.5 2.5 13.0 55.4 9.0 M M
11500 -5.9 21.4 225 16 8 4.6 2.5 12.2 53.9 8.2 M M
11000 -5.2 22.6 220 15 8 3.7 2.0 11.3 52.3 7.4 M M
10500 -4.7 23.5 215 13 7 3.8 2.1 10.3 50.6 6.6 M M
10250 -4.4 24.1 210 13 7 3.1 1.7 9.9 49.7 6.1 M M
10000 -4.2 24.4 210 12 6 2.7 1.5 9.3 48.7 5.6 M M
9750 -4.0 24.8 205 11 6 2.9 1.6 8.7 47.7 5.1 M M
9500 -3.8 25.2 200 11 6 2.9 1.6 8.2 46.8 4.6 M M
9250 -3.6 25.5 195 10 5 3.0 1.6 7.7 45.8 4.1 M M
9000 -3.4 25.9 190 10 5 2.7 1.5 7.1 44.9 3.5 M M
8750 -3.2 26.2 185 9 5 2.5 1.4 6.6 43.8 3.0 M M
8500 -3.1 26.4 180 9 4 2.5 1.3 6.0 42.8 2.4 M M
8250 -2.9 26.8 175 9 5 2.3 1.3 5.4 41.8 1.9 M M
8000 -2.7 27.1 170 9 5 2.4 1.3 4.9 40.8 1.3 M M
7750 -2.5 27.5 165 9 5 2.5 1.4 4.3 39.8 0.8 M M
7500 -2.4 27.7 160 8 4 2.2 1.2 3.7 38.7 0.2 M M
7250 -2.2 28.0 155 8 4 2.9 1.6 3.2 37.7 -0.4 171 0.9
7000 -2.1 28.2 150 8 4 0.1 0.1 2.6 36.7 -0.9 158 0.8
6750 -2.2 28.0 145 8 4 -2.5 -1.4 1.7 35.1 -1.9 156 0.8
6500 -2.4 27.7 140 7 4 -1.9 -1.1 0.8 33.5 -2.8 153 0.8
6250 -2.5 27.5 130 6 3 -1.1 -0.6 -0.1 31.9 -3.6 150 0.8
6000 -2.7 27.1 120 6 3 -4.9 -2.7 -0.9 30.3 -4.5 148 0.7
5750 -3.5 25.7 110 5 3 -17.1 -9.4 -2.5 27.5 -6.1 165 0.8
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 * * * * * *
02/21/2026 AT 0800 MST | 02/21/2026 AT 1100 MST
|
CAPE... 0.0 LI... +6.5 | CAPE... 0.0 LI... +6.2
CINH... -0.2 K INDEX... -10.7 | CINH... 0.0 K INDEX... -12.4
|
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 -55.9 -68.6 280 49 25 2.2 1.2 | -56.7 -70.1 280 48 25 2.2 1.2
45000 -52.6 -62.7 280 54 28 2.2 1.2 | -53.4 -64.1 280 56 29 2.3 1.3
40000 -50.7 -59.3 290 57 29 1.1 0.6 | -53.4 -64.1 290 81 42 -0.1 -0.1
38000 -50.3 -58.5 295 59 30 -1.3 -0.7 | -53.4 -64.1 295 92 47 0.0 0.0
36000 -51.0 -59.8 295 64 33 -1.2 -0.7 | -53.4 -64.1 300 104 54 0.0 0.0
34000 -51.8 -61.2 295 69 36 -1.2 -0.7 | -53.4 -64.1 305 116 60 2.5 1.4
32000 -52.1 -61.8 295 67 34 -0.5 -0.3 | -49.6 -57.3 310 106 55 6.5 3.6
30000 -52.4 -62.3 295 62 32 -1.2 -0.7 | -45.7 -50.3 310 96 50 4.7 2.6
29000 -50.9 -59.6 295 61 31 7.6 4.2 | -45.0 -49.0 310 84 43 2.0 1.1
28000 -48.6 -55.5 295 60 31 7.6 4.2 | -44.4 -47.9 305 72 37 2.0 1.1
27000 -46.3 -51.3 300 59 30 7.6 4.2 | -43.8 -46.8 300 61 31 2.1 1.2
26000 -43.4 -46.1 300 57 29 8.0 4.4 | -42.4 -44.3 295 54 28 7.0 3.8
25000 -41.0 -41.8 300 54 28 8.0 4.4 | -40.3 -40.5 295 51 26 7.1 3.9
24000 -38.6 -37.5 305 52 27 8.0 4.4 | -38.1 -36.6 295 48 25 7.2 3.9
23000 -36.4 -33.5 305 49 25 7.0 3.8 | -36.0 -32.8 295 45 23 7.2 4.0
22000 -34.3 -29.7 310 45 23 7.0 3.8 | -33.3 -27.9 295 42 22 7.2 4.0
21000 -32.2 -26.0 310 42 22 7.0 3.8 | -31.1 -24.0 295 39 20 7.0 3.8
20000 -30.2 -22.4 315 38 20 6.7 3.7 | -29.1 -20.4 300 36 19 6.7 3.7
19500 -29.2 -20.6 315 36 19 6.7 3.7 | -28.1 -18.6 300 34 18 6.7 3.7
19000 -28.2 -18.8 315 35 18 6.7 3.7 | -27.1 -16.8 300 33 17 6.7 3.7
18500 -27.2 -17.0 320 33 17 6.7 3.7 | -26.1 -15.0 300 31 16 6.9 3.8
18000 -26.1 -15.0 320 32 16 7.6 4.2 | -25.0 -13.0 305 29 15 7.0 3.9
17500 -25.0 -13.0 320 30 16 7.5 4.1 | -24.0 -11.2 305 27 14 7.0 3.9
17000 -23.8 -10.8 325 29 15 7.9 4.3 | -22.9 -9.2 305 26 13 7.7 4.2
16500 -22.6 -8.7 325 29 15 7.9 4.4 | -21.7 -7.1 305 24 12 7.7 4.2
16000 -21.4 -6.5 325 28 14 7.7 4.2 | -20.6 -5.1 305 23 12 7.9 4.3
15500 -20.3 -4.5 325 27 14 7.5 4.1 | -19.4 -2.9 305 21 11 7.9 4.3
15000 -19.2 -2.6 325 26 13 7.4 4.1 | -18.2 -0.8 305 20 10 7.7 4.2
14500 -18.1 -0.6 325 24 12 7.1 3.9 | -17.1 1.2 305 18 9 7.5 4.1
14000 -17.0 1.4 325 23 12 7.0 3.9 | -15.9 3.4 310 17 9 7.2 4.0
13500 -16.1 3.0 325 21 11 6.1 3.3 | -14.9 5.2 305 16 8 6.8 3.7
13000 -15.2 4.6 325 20 10 6.1 3.3 | -13.9 7.0 305 14 7 6.4 3.5
12500 -14.4 6.1 320 18 9 4.5 2.4 | -13.1 8.4 305 13 7 5.6 3.1
12000 -13.7 7.3 315 16 8 4.5 2.4 | -12.2 10.0 305 12 6 5.0 2.8
11500 -13.2 8.2 315 14 7 2.8 1.5 | -11.6 11.1 300 11 6 4.0 2.2
11000 -12.8 9.0 310 12 6 2.9 1.6 | -11.0 12.2 295 10 5 3.2 1.8
10500 -12.4 9.7 300 9 5 2.7 1.5 | -10.7 12.7 285 8 4 2.3 1.3
10250 -12.2 10.0 300 8 4 2.5 1.3 | -10.5 13.1 280 7 4 2.3 1.2
10000 -12.0 10.4 290 7 3 3.5 1.9 | -10.3 13.5 275 7 3 2.6 1.4
9750 -11.7 10.9 290 6 3 4.8 2.6 | -10.1 13.8 270 6 3 3.1 1.7
9500 -11.3 11.7 285 5 2 4.6 2.5 | -9.9 14.2 265 5 3 3.0 1.7
9250 -11.0 12.2 275 4 2 4.7 2.6 | -9.7 14.5 250 4 2 3.6 2.0
9000 -10.2 13.6 235 3 1 5.6 3.1 | -9.4 15.1 240 4 2 5.0 2.8
8750 -9.9 14.2 215 2 1 4.7 2.6 | -9.0 15.8 230 4 2 4.6 2.5
8500 -9.5 14.9 195 2 1 5.0 2.8 | -8.7 16.3 220 3 2 3.7 2.0
8250 -9.1 15.6 175 3 1 5.8 3.2 | -8.1 17.4 190 3 2 5.0 2.7
8000 -8.7 16.3 160 4 2 4.8 2.6 | -7.7 18.1 175 4 2 5.3 2.9
7750 -8.4 16.9 150 4 2 3.4 1.9 | -7.3 18.9 170 4 2 6.3 3.4
7500 -8.2 17.2 145 5 3 4.4 2.4 | -6.8 19.8 160 4 2 6.9 3.8
7250 -7.8 18.0 145 6 3 5.7 3.2 | -6.3 20.7 155 4 2 6.5 3.6
7000 -7.4 18.7 140 6 3 3.6 2.8 | -5.8 21.6 155 4 2 8.2 4.5
6750 -7.2 19.0 135 6 3 3.3 1.8 | -5.1 22.8 150 4 2 9.8 5.4
6500 -6.9 19.6 130 5 3 5.0 2.8 | -4.4 24.1 150 4 2 9.6 5.3
6250 -6.5 20.3 125 5 3 4.7 2.6 | -3.7 25.3 150 4 2 9.2 5.0
6000 -6.2 20.8 120 5 2 4.3 2.4 | -3.0 26.6 145 4 2 12.7 6.9
5750 -5.9 21.4 115 5 2 2.4 1.3 | -1.8 28.8 140 4 2 20.1 11.0
5500 -5.8 21.6 105 4 2 2.6 1.4 | -0.5 31.1 135 4 2 7.5 4.1
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
02/21/2026 AT 1400 MST | 02/21/2026 AT 1700 MST
|
CAPE... 0.0 LI... +6.2 | CAPE... 0.0 LI... +6.9
CINH... -0.1 K INDEX... -15.4 | CINH... -0.0 K INDEX... -19.5
|
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 -57.9 -72.2 285 50 25 2.0 1.1 | -59.1 -74.4 285 55 28 0.7 0.4
45000 -54.8 -66.6 285 62 32 2.5 1.4 | -58.0 -72.4 285 78 40 1.0 0.5
40000 -58.5 -73.3 295 98 51 -2.6 -1.4 | -60.1 -76.2 295 103 53 -1.4 -0.8
38000 -57.9 -72.2 300 109 56 5.4 3.0 | -58.4 -73.1 295 109 56 6.7 3.7
36000 -54.7 -66.5 300 113 58 5.4 3.0 | -54.3 -65.7 295 110 56 6.8 3.7
34000 -51.4 -60.5 300 116 60 6.2 3.4 | -50.3 -58.5 295 109 56 6.3 3.5
32000 -47.7 -53.9 300 105 54 6.3 3.5 | -46.5 -51.7 295 98 50 6.4 3.5
30000 -43.9 -47.0 305 95 49 6.1 3.4 | -42.7 -44.9 300 88 45 6.0 3.3
29000 -42.1 -43.8 305 90 46 6.0 3.3 | -40.9 -41.6 295 84 43 6.0 3.3
28000 -40.3 -40.5 305 84 43 6.0 3.3 | -39.1 -38.4 295 80 41 6.0 3.3
27000 -38.5 -37.3 305 79 41 6.1 3.3 | -37.3 -35.1 290 76 39 6.1 3.3
26000 -37.0 -34.6 305 73 38 4.8 2.6 | -34.9 -30.8 295 71 37 6.3 3.5
25000 -35.5 -31.9 305 68 35 4.8 2.6 | -33.0 -27.4 295 68 35 6.3 3.5
24000 -33.7 -28.7 300 60 31 4.7 2.6 | -31.1 -24.0 295 65 33 6.0 3.3
23000 -32.4 -26.3 300 55 28 4.4 2.4 | -29.5 -21.1 300 58 30 5.4 3.0
22000 -31.1 -24.0 295 49 25 4.5 2.4 | -27.8 -18.0 305 52 27 5.4 3.0
21000 -29.7 -21.5 290 44 22 5.7 3.1 | -26.2 -15.2 305 46 24 4.6 2.5
20000 -27.8 -18.0 290 40 21 6.4 3.5 | -24.9 -12.8 305 41 21 4.5 2.5
19500 -26.8 -16.2 290 38 20 6.4 3.5 | -24.2 -11.6 305 39 20 4.5 2.5
19000 -25.9 -14.6 290 37 19 6.4 3.5 | -23.5 -10.3 305 36 19 4.5 2.5
18500 -24.9 -12.8 290 35 18 6.7 3.7 | -22.8 -9.0 305 34 18 5.3 2.9
18000 -23.9 -11.0 290 33 17 6.8 3.8 | -22.0 -7.6 300 33 17 5.6 3.1
17500 -22.8 -9.0 290 31 16 6.9 3.8 | -21.2 -6.2 300 31 16 5.8 3.2
17000 -21.8 -7.2 290 29 15 7.3 4.0 | -20.2 -4.4 295 30 15 6.3 3.4
16500 -20.7 -5.3 290 27 14 7.3 4.0 | -19.3 -2.7 295 29 15 6.2 3.4
16000 -19.6 -3.3 290 25 13 7.4 4.1 | -18.3 -0.9 295 27 14 6.8 3.7
15500 -18.4 -1.1 290 24 12 7.4 4.1 | -17.3 0.9 295 25 13 6.7 3.7
15000 -17.3 0.9 290 22 11 7.6 4.2 | -16.3 2.7 290 24 12 7.2 4.0
14500 -16.2 2.8 290 20 10 7.6 4.2 | -15.2 4.6 290 22 11 7.3 4.0
14000 -15.0 5.0 285 19 10 7.4 4.1 | -14.1 6.6 290 20 10 7.3 4.0
13500 -14.0 6.8 285 17 9 7.2 4.0 | -13.0 8.6 285 18 9 7.3 4.0
13000 -12.9 8.8 285 15 8 6.8 3.7 | -11.9 10.6 285 16 8 6.8 3.7
12500 -11.9 10.6 280 14 7 6.3 3.5 | -10.9 12.4 280 14 7 6.5 3.6
12000 -11.0 12.2 280 12 6 5.7 3.1 | -10.0 14.0 275 13 7 6.1 3.3
11500 -10.2 13.6 275 10 5 5.1 2.8 | -9.1 15.6 270 11 6 5.8 3.2
11000 -9.5 14.9 270 9 5 4.3 2.3 | -8.3 17.1 260 10 5 5.3 2.9
10500 -9.0 15.8 260 7 4 3.8 2.1 | -7.5 18.5 255 8 4 5.1 2.8
10250 -8.7 16.3 255 7 3 3.6 2.0 | -7.2 19.0 250 8 4 4.9 2.7
10000 -8.5 16.7 250 6 3 3.2 1.8 | -6.8 19.8 245 7 4 4.5 2.5
9750 -8.2 17.2 245 6 3 3.6 2.0 | -6.5 20.3 240 7 3 4.5 2.5
9500 -8.0 17.6 240 5 3 3.9 2.1 | -6.2 20.8 230 6 3 4.6 2.5
9250 -7.7 18.1 230 4 2 4.1 2.3 | -5.9 21.4 220 6 3 4.9 2.7
9000 -7.4 18.7 225 4 2 4.8 2.6 | -5.2 22.6 205 5 2 4.5 2.5
8750 -7.1 19.2 220 3 2 4.4 2.4 | -4.9 23.2 195 4 2 4.1 2.3
8500 -6.4 20.5 185 2 1 5.6 3.1 | -4.5 23.9 180 4 2 5.4 2.9
8250 -6.0 21.2 180 2 1 6.3 3.5 | -4.1 24.6 170 3 2 6.1 3.4
8000 -5.5 22.1 170 2 1 6.9 3.8 | -3.7 25.3 160 3 2 5.5 3.0
7750 -4.9 23.2 150 2 1 8.5 4.7 | -3.3 26.1 140 3 1 6.2 3.4
7500 -4.3 24.3 145 2 1 9.1 5.0 | -2.7 27.1 125 3 1 7.4 4.0
7250 -3.6 25.5 140 2 1 8.9 4.9 | -2.2 28.0 115 2 1 7.0 3.9
7000 -2.9 26.8 130 2 1 9.6 5.3 | -1.7 28.9 100 2 1 7.9 4.3
6750 -2.2 28.0 125 2 1 10.1 5.5 | -1.0 30.2 090 2 1 9.0 4.9
6500 -1.5 29.3 125 1 1 9.6 5.3 | -0.4 31.3 085 2 1 8.8 4.8
6250 -0.7 30.7 120 1 1 9.6 5.3 | 0.3 32.5 080 2 1 9.4 5.2
6000 0.1 32.2 100 1 1 13.5 7.4 | 1.1 34.0 065 2 1 11.2 6.1
5750 1.4 34.5 090 1 1 20.3 11.2 | 2.0 35.6 060 3 1 12.0 6.6
5500 2.6 36.7 080 1 1 8.6 4.7 | 2.8 37.0 055 3 1 10.6 5.8
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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