976
UXUS97 KGJT 131306
SRGGJT
SOARING FORECAST
NATIONAL WEATHER SERVICE GRAND JUNCTION, COLORADO
706 AM MDT SATURDAY, SEPTEMBER 13, 2025
THIS FORECAST IS FOR SATURDAY, SEPTEMBER 13, 2025:
IF THE TRIGGER TEMPERATURE OF 66.0 F/18.9 C IS REACHED...THEN
THERMAL SOARING INDEX....................... FAIR
MAXIMUM RATE OF LIFT........................ 354 FT/MIN (1.8 M/S)
MAXIMUM HEIGHT OF THERMALS.................. 14310 FT MSL (8704 FT AGL)
FORECAST MAXIMUM TEMPERATURE................... 72.0 F/22.7 C
TIME OF TRIGGER TEMPERATURE.................... 0945 MDT
TIME OF OVERDEVELOPMENT........................ NONE
MIDDLE/HIGH CLOUDS DURING SOARING WINDOW....... BROKEN/OVERCAST OPAQUE MIDDLE
SURFACE WINDS DURING SOARING WINDOW............ 20 MPH OR LESS
HEIGHT OF THE -3 THERMAL INDEX................. 9724 FT MSL (4118 FT AGL)
THERMAL SOARING OUTLOOK FOR SUNDAY 09/14....... GOOD
WAVE SOARING INDEX............................. NOT AVAILABLE
REMARKS...
SUNRISE/SUNSET.................... 06:54:16 / 19:25:31 MDT
TOTAL POSSIBLE SUNSHINE........... 12 HR 31 MIN 15 SEC (751 MIN 15 SEC)
ALTITUDE OF SUN AT 13:09:53 MDT... 54.29 DEGREES
UPPER AIR DATA FROM RAWINSONDE OBSERVATION TAKEN ON 09/13/2025 AT 0600 MDT
FREEZING LEVEL.................. 12771 FT MSL (7165 FT AGL)
CONVECTIVE CONDENSATION LEVEL... 13759 FT MSL (8153 FT AGL)
LIFTED CONDENSATION LEVEL....... 13959 FT MSL (8353 FT AGL)
LIFTED INDEX.................... -0.7
K INDEX......................... +18.6
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 -59.1 -74.4 300 23 12 1.9 1.1 M M M M M
45000 -55.8 -68.4 300 39 20 3.2 1.8 M M M M M
40000 -50.9 -59.6 300 57 29 3.4 1.9 M M M M M
38000 -48.6 -55.5 305 62 32 3.9 2.2 M M M M M
36000 -46.2 -51.2 305 67 34 3.9 2.2 M M M M M
34000 -42.6 -44.7 305 68 35 6.5 3.5 M M M M M
32000 -38.7 -37.7 310 66 34 6.4 3.5 M M M M M
30000 -34.8 -30.6 310 62 32 6.6 3.6 40.9 105.7 14.2 M M
29000 -32.8 -27.0 310 58 30 6.6 3.6 39.7 103.4 13.4 M M
28000 -30.8 -23.4 315 55 28 6.6 3.6 38.6 101.5 12.7 M M
27000 -29.0 -20.2 315 50 26 5.4 2.9 37.1 98.9 11.7 M M
26000 -27.4 -17.3 315 43 22 5.3 2.9 35.4 95.7 10.5 M M
25000 -25.9 -14.6 315 37 19 5.3 2.9 33.8 92.8 9.3 M M
24000 -24.1 -11.4 315 31 16 7.1 3.9 32.4 90.3 8.3 M M
23000 -22.0 -7.6 315 28 14 7.0 3.8 31.3 88.4 7.5 M M
22000 -19.9 -3.8 310 25 13 7.0 3.8 30.4 86.7 6.8 M M
21000 -17.9 -0.2 310 23 12 6.8 3.8 29.4 84.9 6.0 M M
20000 -15.8 3.6 310 21 11 6.9 3.8 28.3 83.0 5.1 M M
19500 -14.3 6.3 310 19 10 6.9 3.8 27.6 81.7 4.5 M M
19000 -13.3 8.1 310 18 10 6.7 3.6 27.2 80.9 4.1 M M
18500 -12.4 9.7 310 18 9 6.5 3.6 26.6 79.8 3.6 M M
18000 -11.4 11.5 305 17 9 6.5 3.6 26.0 78.8 3.1 M M
17500 -10.5 13.1 305 16 8 6.3 3.5 25.5 77.8 2.6 M M
17000 -9.6 14.7 310 16 8 6.4 3.5 24.9 76.8 2.1 M M
16500 -8.6 16.5 310 15 8 6.8 3.7 24.3 75.8 1.6 M M
16000 -7.6 18.3 310 15 8 7.0 3.8 23.9 74.9 1.1 M M
15500 -6.6 20.1 310 15 8 7.4 4.0 23.4 74.1 0.7 M M
15000 -5.4 22.3 310 14 7 8.0 4.4 23.1 73.6 0.4 M M
14500 -4.3 24.3 310 14 7 8.1 4.4 22.8 73.0 0.1 M M
14000 -3.1 26.4 310 13 7 8.5 4.7 22.6 72.6 -0.2 718 3.6
13500 -1.8 28.8 310 13 7 8.5 4.7 22.4 72.3 -0.4 666 3.4
13000 -0.6 30.9 315 12 6 8.7 4.8 22.2 71.9 -0.6 614 3.1
12500 0.7 33.3 315 12 6 8.8 4.8 22.0 71.6 -0.8 560 2.8
12000 2.0 35.6 315 12 6 8.2 4.5 21.8 71.3 -1.0 508 2.6
11500 3.2 37.8 315 11 6 8.3 4.6 21.6 70.8 -1.2 457 2.3
11000 4.3 39.7 315 10 5 6.8 3.7 21.2 70.2 -1.6 409 2.1
10500 5.3 41.5 315 9 5 8.2 4.5 20.7 69.3 -2.1 365 1.9
10250 5.9 42.6 310 9 5 8.0 4.4 20.7 69.2 -2.2 338 1.7
10000 6.3 43.3 310 8 4 4.8 2.6 20.4 68.7 -2.5 318 1.6
9750 6.7 44.1 310 7 4 4.7 2.6 20.0 67.9 -2.9 301 1.5
9500 7.0 44.6 305 6 3 4.2 2.3 19.6 67.2 -3.3 284 1.4
9250 7.3 45.1 300 5 3 6.4 3.5 19.2 66.5 -3.7 267 1.4
9000 7.8 46.0 295 4 2 6.0 3.3 19.0 66.2 -3.9 244 1.2
8750 8.1 46.6 290 3 2 3.6 2.0 18.5 65.4 -4.4 228 1.2
8500 8.4 47.1 275 2 1 4.2 2.3 18.1 64.6 -4.8 212 1.1
8250 8.7 47.7 245 1 1 3.2 1.7 17.6 63.8 -5.3 197 1.0
8000 8.9 48.0 185 1 1 3.5 1.9 17.1 62.8 -5.9 183 0.9
7750 9.1 48.4 165 2 1 4.2 2.3 16.7 62.0 -6.4 168 0.9
7500 9.4 48.9 155 3 1 3.9 2.2 16.2 61.2 -6.8 153 0.8
7250 9.6 49.3 145 4 2 3.9 2.1 15.8 60.4 -7.3 138 0.7
7000 9.9 49.8 145 5 3 3.1 1.7 15.3 59.6 -7.8 123 0.6
6750 10.1 50.2 140 5 3 3.6 2.0 14.8 58.7 -8.4 109 0.6
6500 10.3 50.5 135 6 3 -0.4 -0.2 14.3 57.7 -8.9 96 0.5
6250 10.0 50.0 130 6 3 -6.4 -3.5 13.2 55.8 -10.0 99 0.5
6000 9.6 49.3 120 6 3 1.9 1.0 12.2 54.0 -11.1 101 0.5
5750 10.0 50.0 115 6 3 2.6 1.4 11.9 53.4 -11.5 83 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 * * * * * *
09/13/2025 AT 0900 MDT | 09/13/2025 AT 1200 MDT
|
CAPE... +313.1 LI... -2.2 | CAPE... +863.6 LI... -4.0
CINH... -157.0 K INDEX... +30.5 | CINH... -38.0 K INDEX... +31.7
|
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 -58.1 -72.6 215 32 16 2.8 1.6 | -57.5 -71.5 225 27 14 3.1 1.7
45000 -53.8 -64.8 215 48 25 3.1 1.7 | -52.8 -63.0 220 41 21 3.0 1.7
40000 -49.2 -56.6 215 64 33 3.1 1.7 | -48.3 -54.9 215 54 28 3.2 1.7
38000 -47.2 -53.0 210 64 33 2.8 1.6 | -46.9 -52.4 210 54 28 2.2 1.2
36000 -45.5 -49.9 210 63 33 2.8 1.6 | -45.4 -49.7 205 54 28 2.2 1.2
34000 -43.9 -47.0 210 59 30 2.5 1.4 | -44.0 -47.2 200 50 26 2.2 1.2
32000 -42.4 -44.3 205 51 26 2.5 1.4 | -42.7 -44.9 200 43 22 2.2 1.2
30000 -39.4 -38.9 200 43 22 7.3 4.0 | -39.9 -39.8 195 37 19 7.4 4.1
29000 -37.3 -35.1 200 39 20 7.3 4.0 | -37.7 -35.9 195 36 18 7.4 4.1
28000 -35.1 -31.2 200 35 18 7.4 4.0 | -35.4 -31.7 195 34 17 7.4 4.1
27000 -32.7 -26.9 200 32 17 8.7 4.8 | -33.1 -27.6 195 32 17 8.3 4.5
26000 -30.1 -22.2 200 31 16 8.7 4.8 | -30.6 -23.1 200 30 16 8.3 4.5
25000 -27.4 -17.3 200 30 16 8.7 4.8 | -28.2 -18.8 200 29 15 8.3 4.5
24000 -24.9 -12.8 200 29 15 7.6 4.2 | -25.8 -14.4 200 27 14 7.6 4.2
23000 -22.1 -7.8 200 27 14 7.7 4.2 | -23.5 -10.3 200 26 14 7.7 4.2
22000 -19.8 -3.6 200 26 14 7.8 4.3 | -20.6 -5.1 200 25 13 7.8 4.3
21000 -17.7 0.1 200 25 13 6.8 3.7 | -18.5 -1.3 200 25 13 6.8 3.7
20000 -15.7 3.7 200 24 12 6.8 3.7 | -16.5 2.3 205 24 13 6.8 3.7
19500 -14.7 5.5 200 23 12 6.8 3.7 | -15.5 4.1 205 24 13 6.9 3.8
19000 -13.7 7.3 200 22 12 6.7 3.7 | -14.5 5.9 205 24 13 7.0 3.9
18500 -12.8 9.0 200 21 11 6.6 3.6 | -13.5 7.7 205 24 12 7.2 4.0
18000 -11.9 10.6 205 20 10 6.5 3.6 | -12.4 9.7 205 23 12 7.2 4.0
17500 -10.8 12.6 205 19 10 7.9 4.4 | -11.4 11.5 205 23 12 7.5 4.1
17000 -9.7 14.5 205 18 9 7.9 4.3 | -10.3 13.5 205 22 11 7.5 4.1
16500 -8.6 16.5 210 17 9 8.1 4.5 | -9.2 15.4 205 22 11 7.7 4.3
16000 -7.4 18.7 210 16 8 8.3 4.5 | -8.1 17.4 210 21 11 7.9 4.3
15500 -6.2 20.8 210 15 8 8.3 4.6 | -6.9 19.6 210 21 11 8.0 4.4
15000 -4.9 23.2 215 15 8 8.4 4.6 | -5.7 21.7 210 21 11 8.3 4.6
14500 -3.7 25.3 215 15 8 8.4 4.6 | -4.5 23.9 215 20 10 8.3 4.6
14000 -2.5 27.5 215 15 7 8.7 4.8 | -3.3 26.1 215 20 10 8.8 4.8
13500 -1.2 29.8 215 14 7 8.6 4.7 | -2.0 28.4 215 19 10 8.8 4.8
13000 0.1 32.2 215 14 7 8.9 4.9 | -0.7 30.7 220 18 9 8.9 4.9
12500 1.4 34.5 210 14 7 8.9 4.9 | 0.6 33.1 220 17 9 8.9 4.9
12000 2.6 36.7 205 14 7 8.2 4.5 | 1.9 35.4 220 16 8 9.0 4.9
11500 3.8 38.8 200 14 7 8.3 4.6 | 3.2 37.8 220 15 8 9.1 5.0
11000 4.9 40.8 195 14 7 6.7 3.7 | 4.4 39.9 215 13 7 7.9 4.4
10500 5.9 42.6 185 15 8 5.9 3.3 | 5.6 42.1 215 11 6 7.2 4.0
10250 6.3 43.3 180 15 8 9.2 5.0 | 6.1 43.0 210 10 5 10.4 5.7
10000 7.1 44.8 180 14 7 9.4 5.2 | 7.0 44.6 210 10 5 10.5 5.8
9750 7.6 45.7 175 13 7 6.3 3.4 | 7.6 45.7 210 9 5 7.3 4.0
9500 8.1 46.6 170 13 7 7.3 4.0 | 8.1 46.6 205 9 4 8.5 4.7
9250 8.6 47.5 165 13 7 6.4 3.5 | 8.7 47.7 205 8 4 6.9 3.8
9000 9.1 48.4 160 15 8 6.4 3.5 | 9.2 48.6 195 6 3 7.0 3.9
8750 9.6 49.3 155 14 7 6.9 3.8 | 9.7 49.5 195 6 3 8.2 4.5
8500 10.1 50.2 150 14 7 7.1 3.9 | 10.3 50.5 195 5 3 8.6 4.7
8250 10.9 51.6 145 14 7 4.6 2.5 | 10.9 51.6 195 5 2 5.4 3.0
8000 11.3 52.3 140 14 7 5.8 3.2 | 11.2 52.2 185 3 2 4.2 2.3
7750 11.7 53.1 135 12 6 5.6 3.1 | 12.2 54.0 185 2 1 8.3 4.6
7500 12.1 53.8 130 11 6 4.0 2.2 | 12.7 54.9 200 1 0 4.1 2.3
7250 12.3 54.1 125 12 6 3.1 1.7 | 12.9 55.2 005 1 0 2.3 1.3
7000 12.6 54.7 125 12 6 4.4 2.4 | 13.3 55.9 005 2 1 9.4 5.2
6750 12.9 55.2 110 10 5 4.8 2.6 | 14.1 57.4 355 2 1 10.6 5.8
6500 13.2 55.8 105 9 5 4.5 2.5 | 14.6 58.3 355 2 1 6.3 3.5
6250 13.5 56.3 100 8 4 4.1 2.3 | 15.1 59.2 360 3 2 5.8 3.2
6000 13.8 56.8 100 7 4 6.2 3.4 | 15.5 59.9 360 4 2 10.1 5.5
5750 14.4 57.9 090 6 3 11.1 6.1 | 16.7 62.1 350 3 2 21.9 12.0
5500 15.1 59.2 075 5 3 4.5 2.5 | 18.2 64.8 005 3 2 14.5 8.0
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
09/13/2025 AT 1500 MDT | 09/13/2025 AT 1800 MDT
|
CAPE... +655.2 LI... -1.7 | CAPE... +223.2 LI... -0.9
CINH... -35.5 K INDEX... +26.3 | CINH... -128.7 K INDEX... +21.2
|
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 -57.3 -71.1 240 20 10 2.8 1.5 | -57.2 -71.0 250 17 9 2.9 1.6
45000 -52.9 -63.2 235 31 16 3.4 1.9 | -52.7 -62.9 245 24 12 3.2 1.8
40000 -47.8 -54.0 220 41 21 3.8 2.1 | -47.9 -54.2 230 29 15 3.5 1.9
38000 -47.4 -53.3 215 38 20 0.1 0.1 | -47.1 -52.8 225 28 15 1.1 0.6
36000 -47.3 -53.1 205 34 18 0.1 0.1 | -46.4 -51.5 210 28 15 1.1 0.6
34000 -45.8 -50.4 200 30 15 4.7 2.6 | -45.0 -49.0 205 25 13 3.6 2.0
32000 -43.0 -45.4 205 24 12 4.7 2.6 | -42.8 -45.0 190 19 10 3.6 2.0
30000 -39.2 -38.6 205 21 11 8.1 4.4 | -39.3 -38.7 185 15 8 8.3 4.5
29000 -36.8 -34.2 205 22 11 8.1 4.4 | -36.9 -34.4 195 14 7 8.3 4.5
28000 -34.4 -29.9 200 22 11 8.1 4.4 | -34.4 -29.9 200 13 7 8.3 4.5
27000 -32.0 -25.6 200 22 11 8.0 4.4 | -32.0 -25.6 210 13 7 7.6 4.2
26000 -29.6 -21.3 200 23 12 8.0 4.4 | -29.7 -21.5 220 14 7 7.7 4.2
25000 -27.2 -17.0 195 23 12 8.1 4.4 | -27.5 -17.5 230 15 8 7.7 4.2
24000 -24.9 -12.8 195 23 12 7.2 4.0 | -25.2 -13.4 235 16 8 7.0 3.9
23000 -22.2 -8.0 195 23 12 7.3 4.0 | -23.1 -9.6 245 17 9 7.1 3.9
22000 -20.0 -4.0 195 22 12 7.3 4.0 | -20.5 -4.9 250 17 9 7.1 3.9
21000 -17.8 -0.0 195 22 11 7.5 4.1 | -18.4 -1.1 255 18 9 6.8 3.7
20000 -15.6 3.9 200 21 11 7.5 4.1 | -16.4 2.5 260 19 10 6.8 3.7
19500 -14.5 5.9 200 21 11 7.5 4.1 | -15.4 4.3 260 19 10 6.8 3.7
19000 -13.4 7.9 200 20 11 7.2 3.9 | -14.4 6.1 265 19 10 7.1 3.9
18500 -12.4 9.7 200 20 10 6.7 3.7 | -13.3 8.1 265 19 10 7.4 4.1
18000 -11.4 11.5 200 20 10 6.7 3.7 | -12.2 10.0 265 20 10 7.4 4.0
17500 -10.5 13.1 205 19 10 6.5 3.6 | -11.1 12.0 270 20 10 8.0 4.4
17000 -9.5 14.9 205 19 10 6.6 3.6 | -9.9 14.2 270 20 10 8.0 4.4
16500 -8.6 16.5 205 18 9 6.5 3.6 | -8.7 16.3 270 20 11 8.1 4.4
16000 -7.6 18.3 205 18 9 6.5 3.6 | -7.5 18.5 270 20 11 8.1 4.5
15500 -6.7 19.9 210 17 9 6.6 3.6 | -6.3 20.7 270 20 10 8.1 4.5
15000 -5.7 21.7 210 17 9 6.9 3.8 | -5.1 22.8 275 20 10 8.1 4.4
14500 -4.7 23.5 215 16 8 6.9 3.8 | -4.0 24.8 275 20 10 8.1 4.5
14000 -3.7 25.3 215 15 8 7.1 3.9 | -2.8 27.0 275 19 10 8.1 4.5
13500 -2.6 27.3 220 15 7 7.1 3.9 | -1.6 29.1 275 19 10 8.2 4.5
13000 -1.6 29.1 225 14 7 7.2 3.9 | -0.4 31.3 280 18 9 7.6 4.2
12500 -0.5 31.1 230 13 7 7.2 4.0 | 0.7 33.3 280 17 9 7.6 4.2
12000 0.5 32.9 240 13 7 6.9 3.8 | 1.7 35.1 280 15 8 7.4 4.0
11500 1.5 34.7 245 12 6 6.8 3.8 | 2.8 37.0 280 14 7 7.4 4.1
11000 2.5 36.5 255 12 6 7.6 4.2 | 3.8 38.8 280 12 6 6.1 3.3
10500 3.7 38.7 260 12 6 8.2 4.5 | 4.6 40.3 280 10 5 5.3 2.9
10250 4.2 39.6 265 12 6 6.3 3.4 | 5.1 41.2 285 9 5 7.9 4.3
10000 4.6 40.3 270 12 6 6.5 3.6 | 5.7 42.3 270 7 4 8.6 4.7
9750 5.2 41.4 270 12 6 8.8 4.8 | 6.2 43.2 270 6 3 6.6 3.6
9500 5.8 42.4 275 12 6 7.7 4.2 | 6.7 44.1 265 5 3 7.1 3.9
9250 6.4 43.5 275 13 6 9.8 5.4 | 7.2 45.0 260 4 2 7.0 3.8
9000 7.2 45.0 280 13 7 8.8 4.8 | 7.8 46.0 265 4 2 7.1 3.9
8750 7.7 45.9 285 13 7 6.1 3.3 | 8.3 46.9 260 3 2 7.2 3.9
8500 8.1 46.6 285 13 6 6.4 3.5 | 8.8 47.8 245 2 1 7.4 4.1
8250 9.2 48.6 290 13 7 7.9 4.4 | 9.3 48.7 215 2 1 6.4 3.5
8000 9.7 49.5 295 12 6 7.0 3.8 | 10.2 50.4 190 1 1 7.7 4.2
7750 10.2 50.4 295 11 6 6.8 3.7 | 10.8 51.4 145 2 1 7.8 4.3
7500 10.7 51.3 300 11 6 6.4 3.5 | 11.3 52.3 125 3 2 5.5 3.0
7250 11.1 52.0 300 11 6 6.2 3.4 | 11.6 52.9 120 4 2 4.0 2.2
7000 11.5 52.7 305 11 6 6.6 3.6 | 12.0 53.6 115 4 2 7.9 4.3
6750 12.0 53.6 310 9 5 7.4 4.1 | 12.6 54.7 105 5 3 7.7 4.2
6500 12.5 54.5 310 9 5 7.9 4.4 | 13.0 55.4 105 6 3 4.2 2.3
6250 13.1 55.6 315 9 5 7.9 4.3 | 13.3 55.9 100 7 4 3.8 2.1
6000 13.6 56.5 315 9 4 7.9 4.3 | 13.5 56.3 100 7 4 5.7 3.1
5750 14.2 57.6 320 7 3 10.8 5.9 | 14.1 57.4 095 6 3 10.3 5.6
5500 15.3 59.5 320 6 3 23.6 13.0 | 14.6 58.3 095 6 3 4.4 2.4
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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