813
UXUS97 KGJT 091306
SRGGJT
SOARING FORECAST
NATIONAL WEATHER SERVICE GRAND JUNCTION, COLORADO
706 AM MDT FRIDAY, OCTOBER 9, 2026
THIS FORECAST IS FOR FRIDAY, OCTOBER 9, 2026:
IF THE TRIGGER TEMPERATURE OF 72.5 F/22.5 C IS REACHED...THEN
THERMAL SOARING INDEX....................... EXCELLENT
MAXIMUM RATE OF LIFT........................ 1468 FT/MIN (7.5 M/S)
MAXIMUM HEIGHT OF THERMALS.................. 19163 FT MSL (13556 FT AGL)
FORECAST MAXIMUM TEMPERATURE................... 83.0 F/28.8 C
TIME OF TRIGGER TEMPERATURE.................... 1030 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................. 16234 FT MSL (10627 FT AGL)
THERMAL SOARING OUTLOOK FOR SATURDAY 10/10..... EXCELLENT
WAVE SOARING INDEX............................. NOT AVAILABLE
REMARKS...
SUNRISE/SUNSET.................... 07:18:12 / 18:44:26 MDT
TOTAL POSSIBLE SUNSHINE........... 11 HR 26 MIN 14 SEC (686 MIN 14 SEC)
ALTITUDE OF SUN AT 13:01:19 MDT... 44.40 DEGREES
UPPER AIR DATA FROM RAWINSONDE OBSERVATION TAKEN ON 10/09/2026 AT 0600 MDT
FREEZING LEVEL.................. 13460 FT MSL (7853 FT AGL)
CONVECTIVE CONDENSATION LEVEL... 14443 FT MSL (8836 FT AGL)
LIFTED CONDENSATION LEVEL....... 16288 FT MSL (10681 FT AGL)
LIFTED INDEX.................... -2.1
K INDEX......................... +28.7
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 -62.0 -79.6 275 43 22 2.4 1.3 M M M M M
45000 -58.4 -73.1 270 49 25 2.1 1.2 M M M M M
40000 -55.3 -67.5 260 53 27 2.6 1.4 M M M M M
38000 -52.0 -61.6 260 51 26 5.7 3.1 M M M M M
36000 -48.2 -54.8 260 47 24 5.6 3.1 M M M M M
34000 -43.9 -47.0 260 45 23 7.9 4.4 M M M M M
32000 -39.2 -38.6 255 43 22 7.9 4.4 M M M M M
30000 -34.6 -30.3 255 41 21 7.5 4.1 40.5 104.9 9.3 M M
29000 -32.3 -26.1 255 40 21 7.5 4.1 39.6 103.3 8.7 M M
28000 -30.1 -22.2 255 39 20 7.5 4.1 38.8 101.9 8.2 M M
27000 -27.8 -18.0 255 38 20 7.5 4.1 38.0 100.3 7.6 M M
26000 -25.6 -14.1 255 37 19 7.5 4.1 37.1 98.7 7.0 M M
25000 -23.3 -9.9 255 35 18 7.5 4.1 36.3 97.3 6.4 M M
24000 -21.1 -6.0 255 34 17 6.8 3.7 35.4 95.8 5.8 M M
23000 -19.1 -2.4 250 33 17 6.9 3.8 34.3 93.8 4.9 M M
22000 -17.1 1.2 245 31 16 6.9 3.8 33.4 92.0 4.1 M M
21000 -15.3 4.5 245 30 15 4.8 2.6 32.0 89.7 3.0 M M
20000 -13.5 7.7 235 29 15 4.9 2.7 29.9 85.7 1.1 M M
19500 -12.8 9.0 235 29 15 5.0 2.8 29.0 84.3 0.3 M M
19000 -12.1 10.2 230 29 15 5.8 3.2 28.3 82.9 -0.4 1249 6.3
18500 -11.2 11.8 230 28 14 6.4 3.5 27.7 81.8 -1.0 1207 6.1
18000 -10.3 13.5 230 27 14 6.4 3.5 27.1 80.8 -1.5 1165 5.9
17500 -9.3 15.3 230 27 14 7.4 4.1 26.6 79.9 -2.0 1121 5.7
17000 -8.3 17.1 230 26 13 7.3 4.0 26.2 79.2 -2.4 1075 5.5
16500 -7.2 19.0 230 26 13 7.6 4.2 25.8 78.5 -2.8 1028 5.2
16000 -6.1 21.0 230 25 13 7.7 4.2 25.5 77.8 -3.2 980 5.0
15500 -5.0 23.0 230 25 13 7.9 4.3 25.1 77.2 -3.6 932 4.7
15000 -3.8 25.2 230 25 13 8.4 4.6 24.9 76.8 -3.9 881 4.5
14500 -2.6 27.3 230 24 13 8.3 4.6 24.6 76.4 -4.1 830 4.2
14000 -1.3 29.7 230 24 13 8.7 4.8 24.5 76.0 -4.4 777 3.9
13500 -0.1 31.8 230 24 13 8.6 4.7 24.3 75.7 -4.6 724 3.7
13000 1.3 34.3 230 24 13 9.4 5.2 24.2 75.5 -4.7 670 3.4
12500 2.6 36.7 235 24 13 9.4 5.2 24.1 75.4 -4.8 613 3.1
12000 4.0 39.2 235 24 13 9.5 5.2 24.1 75.3 -4.9 557 2.8
11500 5.4 41.7 235 24 12 9.5 5.2 24.0 75.2 -5.0 500 2.5
11000 6.8 44.2 235 24 12 8.6 4.7 23.9 75.1 -5.1 444 2.3
10500 8.0 46.4 235 23 12 9.5 5.2 23.7 74.7 -5.3 392 2.0
10250 8.8 47.8 230 22 11 10.4 5.7 23.8 74.8 -5.3 362 1.8
10000 9.5 49.1 230 22 11 8.6 4.7 23.7 74.7 -5.3 333 1.7
9750 10.1 50.2 230 20 11 8.0 4.4 23.6 74.5 -5.5 307 1.6
9500 10.7 51.3 230 19 10 8.3 4.6 23.5 74.3 -5.6 282 1.4
9250 11.4 52.5 230 18 9 8.1 4.5 23.4 74.1 -5.7 256 1.3
9000 11.9 53.4 225 17 9 7.1 3.9 23.2 73.8 -5.9 231 1.2
8750 12.4 54.3 220 16 8 6.6 3.6 23.0 73.4 -6.2 209 1.1
8500 12.9 55.2 215 16 8 6.9 3.8 22.7 72.9 -6.4 187 0.9
8250 13.4 56.1 210 15 8 6.1 3.4 22.5 72.5 -6.6 164 0.8
8000 13.8 56.8 205 15 8 4.8 2.6 22.2 71.9 -7.0 145 0.7
7750 14.2 57.6 200 14 7 4.6 2.5 21.8 71.2 -7.4 127 0.6
7500 14.5 58.1 195 13 7 4.9 2.7 21.4 70.5 -7.8 109 0.6
7250 14.9 58.8 185 13 7 3.1 1.7 21.0 69.8 -8.2 92 0.5
7000 15.0 59.0 175 15 8 2.3 1.3 20.4 68.8 -8.8 80 0.4
6750 15.3 59.5 170 14 7 3.7 2.0 19.9 67.9 -9.3 65 0.3
6500 15.5 59.9 165 14 7 2.0 1.1 19.4 67.0 -9.8 51 0.3
6250 15.5 59.9 155 13 7 -3.5 -1.9 18.7 65.6 -10.6 45 0.2
6000 15.1 59.2 150 11 6 -1.3 -0.7 17.6 63.7 -11.7 46 0.2
5750 15.1 59.2 140 9 5 -2.3 -1.3 16.9 62.4 -12.4 39 0.2
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 * * * * * *
10/09/2026 AT 0900 MDT | 10/09/2026 AT 1200 MDT
|
CAPE... +0.4 LI... -0.3 | CAPE... +26.8 LI... -0.4
CINH... -0.8 K INDEX... +23.7 | CINH... -21.4 K INDEX... +25.6
|
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 -63.7 -82.7 290 25 13 2.6 1.4 | -63.6 -82.5 270 27 14 2.8 1.5
45000 -58.6 -73.5 285 26 13 5.3 2.9 | -58.7 -73.7 270 30 15 5.1 2.8
40000 -50.7 -59.3 285 19 10 4.3 2.3 | -50.6 -59.1 275 23 12 4.8 2.6
38000 -48.2 -54.8 275 14 7 4.2 2.3 | -47.7 -53.9 275 21 11 4.8 2.6
36000 -45.6 -50.1 255 10 5 4.2 2.3 | -44.8 -48.6 275 18 9 4.8 2.6
34000 -42.7 -44.9 200 8 4 5.2 2.9 | -41.8 -43.2 255 14 7 5.0 2.7
32000 -39.5 -39.1 150 14 7 5.2 2.9 | -38.8 -37.8 220 13 7 5.0 2.7
30000 -36.0 -32.8 145 17 9 6.3 3.4 | -35.9 -32.6 195 15 8 4.8 2.6
29000 -34.2 -29.6 150 17 9 6.3 3.4 | -34.5 -30.1 190 16 8 4.8 2.6
28000 -32.3 -26.1 155 16 8 6.2 3.4 | -33.1 -27.6 185 17 9 4.7 2.6
27000 -29.5 -21.1 165 16 8 7.9 4.4 | -31.0 -23.8 185 18 9 8.2 4.5
26000 -27.1 -16.8 175 15 8 7.9 4.4 | -27.9 -18.2 195 18 9 8.3 4.6
25000 -24.8 -12.6 185 15 8 8.0 4.4 | -25.4 -13.7 200 19 10 8.3 4.6
24000 -22.5 -8.5 190 15 8 7.6 4.1 | -23.0 -9.4 205 18 9 8.0 4.4
23000 -20.2 -4.4 200 16 8 7.6 4.2 | -20.6 -5.1 210 18 9 8.0 4.4
22000 -17.9 -0.2 205 16 8 7.7 4.2 | -18.3 -0.9 215 18 9 8.3 4.5
21000 -16.1 3.0 210 16 8 6.0 3.3 | -16.2 2.8 215 17 9 6.4 3.5
20000 -14.3 6.3 215 15 8 6.1 3.3 | -14.4 6.1 220 17 9 6.5 3.6
19500 -13.4 7.9 215 15 8 6.1 3.4 | -13.4 7.9 220 17 9 6.5 3.6
19000 -12.5 9.5 220 15 8 6.5 3.6 | -12.5 9.5 225 16 8 6.5 3.6
18500 -11.6 11.1 220 14 7 6.7 3.7 | -11.5 11.3 225 16 8 6.6 3.6
18000 -10.6 12.9 225 14 7 6.9 3.8 | -10.6 12.9 225 16 8 6.7 3.7
17500 -9.5 14.9 225 14 7 7.6 4.2 | -9.5 14.9 225 16 8 7.5 4.1
17000 -8.4 16.9 230 14 7 7.5 4.1 | -8.5 16.7 225 15 8 7.4 4.1
16500 -7.3 18.9 230 14 7 8.4 4.6 | -7.3 18.9 230 15 8 8.2 4.5
16000 -6.0 21.2 230 14 7 8.4 4.6 | -6.1 21.0 230 15 8 8.3 4.6
15500 -4.8 23.4 230 14 7 8.7 4.8 | -4.9 23.2 230 15 8 8.6 4.7
15000 -3.5 25.7 230 14 7 8.9 4.9 | -3.6 25.5 230 15 8 8.8 4.8
14500 -2.2 28.0 230 13 7 9.0 4.9 | -2.3 27.9 230 15 8 8.8 4.9
14000 -0.8 30.6 230 13 7 9.1 5.0 | -1.0 30.2 230 15 8 8.8 4.8
13500 0.5 32.9 230 12 6 9.1 5.0 | 0.3 32.5 230 15 8 8.8 4.8
13000 1.9 35.4 230 12 6 9.1 5.0 | 1.7 35.1 225 14 7 9.1 5.0
12500 3.2 37.8 230 12 6 9.1 5.0 | 3.0 37.4 225 14 7 9.0 5.0
12000 4.6 40.3 230 11 6 9.2 5.0 | 4.3 39.7 225 14 7 9.2 5.0
11500 5.9 42.6 225 11 5 9.3 5.1 | 5.7 42.3 225 14 7 9.3 5.1
11000 7.3 45.1 225 10 5 8.7 4.7 | 7.0 44.6 225 13 7 7.7 4.2
10500 8.6 47.5 225 10 5 9.4 5.1 | 8.1 46.6 220 13 7 7.1 3.9
10250 9.2 48.6 220 9 5 6.0 3.3 | 8.7 47.7 220 13 6 10.4 5.7
10000 9.5 49.1 220 9 5 6.5 3.6 | 9.6 49.3 220 12 6 11.0 6.0
9750 10.2 50.4 215 9 5 10.0 5.5 | 10.3 50.5 220 12 6 8.0 4.4
9500 10.9 51.6 210 9 4 9.5 5.2 | 10.9 51.6 215 12 6 9.3 5.1
9250 12.1 53.8 205 8 4 6.3 3.5 | 11.5 52.7 215 11 6 7.3 4.0
9000 12.6 54.7 200 8 4 7.6 4.2 | 12.7 54.9 215 10 5 9.1 5.0
8750 13.2 55.8 195 9 4 7.2 4.0 | 13.3 55.9 210 10 5 8.9 4.9
8500 13.7 56.7 190 9 5 6.3 3.5 | 13.9 57.0 210 10 5 6.6 3.6
8250 14.1 57.4 185 9 5 5.7 3.1 | 14.4 57.9 205 9 5 6.6 3.6
8000 14.5 58.1 180 9 5 6.3 3.5 | 15.0 59.0 205 9 5 9.6 5.3
7750 15.0 59.0 175 9 4 5.5 3.0 | 15.7 60.3 205 9 5 9.1 5.0
7500 15.3 59.5 170 9 5 3.8 2.1 | 16.3 61.3 200 9 5 7.1 3.9
7250 15.6 60.1 165 10 5 3.3 1.8 | 16.8 62.2 200 9 4 6.8 3.7
7000 15.9 60.6 165 10 5 4.0 2.2 | 17.4 63.3 195 8 4 11.0 6.1
6750 16.1 61.0 160 8 4 2.2 1.2 | 18.3 64.9 195 8 4 10.7 5.9
6500 16.2 61.2 155 8 4 0.2 0.1 | 18.9 66.0 195 7 4 7.6 4.2
6250 16.2 61.2 150 8 4 0.7 0.4 | 19.5 67.1 190 7 4 7.9 4.3
6000 16.3 61.3 145 8 4 2.1 1.1 | 20.1 68.2 185 6 3 9.0 4.9
5750 16.5 61.7 130 5 3 2.3 1.3 | 20.9 69.6 185 6 3 11.8 6.5
5500 16.1 61.0 105 4 2 -15.3 -8.4 | 21.6 70.9 175 4 2 6.6 3.6
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
10/09/2026 AT 1500 MDT | 10/09/2026 AT 1800 MDT
|
CAPE... +195.4 LI... -1.9 | CAPE... +118.9 LI... -1.3
CINH... -16.0 K INDEX... +28.0 | CINH... -87.5 K INDEX... +25.5
|
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 -63.3 -81.9 275 32 16 2.5 1.4 | -63.3 -81.9 275 36 18 2.5 1.4
45000 -59.0 -74.2 275 32 17 4.5 2.5 | -59.1 -74.4 275 35 18 4.0 2.2
40000 -51.9 -61.4 275 31 16 5.6 3.1 | -52.6 -62.7 275 33 17 5.4 2.9
38000 -48.4 -55.1 280 30 16 5.7 3.1 | -49.3 -56.7 280 35 18 5.5 3.0
36000 -45.0 -49.0 285 31 16 5.7 3.1 | -46.0 -50.8 285 37 19 5.5 3.0
34000 -41.4 -42.5 285 29 15 6.1 3.4 | -42.1 -43.8 290 37 19 6.9 3.8
32000 -37.8 -36.0 280 26 14 6.1 3.4 | -37.9 -36.2 290 36 19 6.9 3.8
30000 -34.7 -30.5 265 22 11 4.5 2.5 | -34.0 -29.2 290 33 17 6.3 3.5
29000 -33.3 -27.9 255 19 10 4.5 2.5 | -32.1 -25.8 285 31 16 6.3 3.5
28000 -32.0 -25.6 240 18 9 4.6 2.5 | -30.2 -22.4 285 29 15 6.3 3.5
27000 -30.3 -22.5 230 19 10 6.5 3.5 | -28.4 -19.1 280 26 14 5.7 3.1
26000 -28.4 -19.1 220 19 10 6.5 3.6 | -26.7 -16.1 270 23 12 5.7 3.1
25000 -25.9 -14.6 210 21 11 6.5 3.6 | -25.0 -13.0 255 21 11 5.8 3.2
24000 -23.7 -10.7 210 21 11 7.7 4.2 | -22.8 -9.0 240 21 11 6.1 3.4
23000 -21.4 -6.5 210 20 10 7.8 4.3 | -21.0 -5.8 235 20 10 6.2 3.4
22000 -19.1 -2.4 215 19 10 7.9 4.3 | -19.2 -2.6 230 19 10 6.1 3.4
21000 -17.1 1.2 215 19 10 6.7 3.7 | -17.2 1.0 230 19 10 7.2 4.0
20000 -15.1 4.8 210 19 10 6.8 3.7 | -15.0 5.0 230 18 9 7.3 4.0
19500 -14.1 6.6 210 19 10 6.8 3.8 | -14.0 6.8 225 18 9 7.3 4.0
19000 -13.1 8.4 210 19 10 7.8 4.3 | -12.9 8.8 225 18 9 7.7 4.2
18500 -11.9 10.6 210 19 10 8.3 4.6 | -11.7 10.9 225 18 9 7.9 4.3
18000 -10.7 12.7 210 19 10 8.4 4.6 | -10.6 12.9 225 18 9 7.9 4.4
17500 -9.5 14.9 210 19 10 8.5 4.7 | -9.4 15.1 225 18 9 7.9 4.3
17000 -8.3 17.1 210 19 10 8.5 4.7 | -8.3 17.1 225 18 9 7.9 4.3
16500 -7.0 19.4 210 18 9 8.3 4.5 | -7.1 19.2 230 18 9 8.3 4.5
16000 -5.8 21.6 215 18 9 8.2 4.5 | -5.9 21.4 230 18 9 8.4 4.6
15500 -4.6 23.7 215 18 9 8.4 4.6 | -4.6 23.7 230 18 9 8.5 4.7
15000 -3.4 25.9 215 17 9 8.7 4.8 | -3.3 26.1 230 18 9 8.8 4.8
14500 -2.1 28.2 220 17 9 8.8 4.8 | -2.0 28.4 230 18 9 8.8 4.8
14000 -0.7 30.7 220 16 8 9.3 5.1 | -0.7 30.7 230 18 9 9.1 5.0
13500 0.7 33.3 220 16 8 9.3 5.1 | 0.6 33.1 230 18 9 9.0 5.0
13000 2.1 35.8 220 16 8 9.5 5.2 | 2.0 35.6 230 18 9 9.2 5.0
12500 3.5 38.3 220 15 8 9.5 5.2 | 3.3 37.9 230 17 9 9.1 5.0
12000 4.9 40.8 225 15 8 9.4 5.2 | 4.7 40.5 230 17 9 9.4 5.2
11500 6.3 43.3 225 14 7 9.5 5.2 | 6.1 43.0 230 17 9 9.5 5.2
11000 7.6 45.7 225 14 7 8.6 4.7 | 7.4 45.3 230 17 9 8.1 4.5
10500 8.9 48.0 230 12 6 8.2 4.5 | 8.6 47.5 225 16 8 7.2 3.9
10250 9.6 49.3 230 12 6 10.8 5.9 | 9.2 48.6 225 16 8 11.6 6.3
10000 10.5 50.9 230 13 7 11.1 6.1 | 10.3 50.5 225 16 8 12.3 6.8
9750 11.2 52.2 230 13 7 9.0 4.9 | 10.9 51.6 225 16 8 8.5 4.7
9500 11.9 53.4 230 13 6 9.6 5.3 | 11.6 52.9 225 16 8 9.8 5.4
9250 12.6 54.7 230 12 6 9.2 5.1 | 12.3 54.1 225 16 8 8.3 4.6
9000 13.9 57.0 235 11 5 9.0 4.9 | 12.9 55.2 225 16 8 8.6 4.7
8750 14.6 58.3 235 11 6 9.4 5.1 | 13.6 56.5 225 16 8 9.9 5.4
8500 15.3 59.5 235 11 6 7.9 4.4 | 15.1 59.2 220 16 8 9.0 5.0
8250 15.8 60.4 245 9 5 8.1 4.4 | 15.7 60.3 220 15 8 8.4 4.6
8000 16.5 61.7 245 9 5 10.0 5.5 | 16.3 61.3 220 15 8 8.7 4.7
7750 17.2 63.0 240 9 5 10.0 5.5 | 17.0 62.6 220 14 7 8.9 4.9
7500 17.9 64.2 240 9 5 7.8 4.3 | 17.6 63.7 220 14 7 7.4 4.1
7250 18.4 65.1 250 7 4 7.1 3.9 | 18.1 64.6 220 14 7 6.4 3.5
7000 19.1 66.4 255 7 3 10.9 6.0 | 18.6 65.5 220 13 7 7.9 4.3
6750 20.0 68.0 250 7 4 11.8 6.5 | 19.2 66.6 215 12 6 7.8 4.3
6500 20.8 69.4 250 7 3 10.1 5.5 | 19.7 67.5 215 11 6 6.0 3.3
6250 21.5 70.7 260 6 3 10.2 5.6 | 20.0 68.0 215 10 5 5.6 3.1
6000 22.3 72.1 265 6 3 8.5 4.7 | 20.4 68.7 215 9 4 4.3 2.4
5750 22.9 73.2 250 6 3 11.4 6.3 | 20.6 69.1 205 7 4 1.3 0.7
5500 24.9 76.8 275 5 3 51.8 28.4 | 20.7 69.3 205 4 2 8.2 4.5
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
________________________________________________________________________________
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.
042613
CLICK HERE TO GO TO PREVIOUS BULLETINS.
Main Text Page