259
UXUS97 KGJT 141306
SRGGJT
SOARING FORECAST
NATIONAL WEATHER SERVICE GRAND JUNCTION, COLORADO
706 AM MDT MONDAY, SEPTEMBER 14, 2026
THIS FORECAST IS FOR MONDAY, SEPTEMBER 14, 2026:
IF THE TRIGGER TEMPERATURE OF 74.0 F/23.3 C IS REACHED...THEN
THERMAL SOARING INDEX....................... EXCELLENT
MAXIMUM RATE OF LIFT........................ 947 FT/MIN (4.8 M/S)
MAXIMUM HEIGHT OF THERMALS.................. 14256 FT MSL (8646 FT AGL)
FORECAST MAXIMUM TEMPERATURE................... 80.0 F/27.1 C
TIME OF TRIGGER TEMPERATURE.................... 1130 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................. 9974 FT MSL (4365 FT AGL)
THERMAL SOARING OUTLOOK FOR TUESDAY 09/15...... EXCELLENT
WAVE SOARING INDEX............................. NOT AVAILABLE
REMARKS...
SUNRISE/SUNSET.................... 06:54:57 / 19:24:17 MDT
TOTAL POSSIBLE SUNSHINE........... 12 HR 29 MIN 20 SEC (749 MIN 20 SEC)
ALTITUDE OF SUN AT 13:09:37 MDT... 54.00 DEGREES
UPPER AIR DATA FROM RAWINSONDE OBSERVATION TAKEN ON 09/14/2026 AT 0600 MDT
FREEZING LEVEL.................. 14661 FT MSL (9051 FT AGL)
CONVECTIVE CONDENSATION LEVEL... 11908 FT MSL (6298 FT AGL)
LIFTED CONDENSATION LEVEL....... 12829 FT MSL (7219 FT AGL)
LIFTED INDEX.................... -3.4
K INDEX......................... +29.7
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 -63.3 -81.9 250 57 29 0.6 0.3 M M M M M
45000 -60.3 -76.5 245 82 42 5.2 2.9 M M M M M
40000 -52.3 -62.1 240 81 42 6.3 3.4 M M M M M
38000 -48.6 -55.5 245 73 38 6.3 3.4 M M M M M
36000 -44.8 -48.6 245 66 34 6.3 3.4 M M M M M
34000 -40.3 -40.5 250 58 30 6.8 3.7 M M M M M
32000 -36.2 -33.2 250 51 26 6.7 3.7 M M M M M
30000 -31.7 -25.1 250 47 24 7.7 4.2 43.2 109.7 12.6 M M
29000 -29.4 -20.9 250 45 23 7.7 4.2 42.4 108.4 12.2 M M
28000 -27.1 -16.8 250 43 22 7.8 4.3 41.8 107.2 11.8 M M
27000 -24.7 -12.5 250 39 20 7.9 4.4 41.0 105.7 11.3 M M
26000 -22.4 -8.3 250 36 19 7.9 4.4 40.3 104.5 10.8 M M
25000 -20.0 -4.0 250 33 17 8.1 4.4 39.7 103.5 10.4 M M
24000 -17.8 -0.0 245 32 17 7.3 4.0 38.8 101.8 9.8 M M
23000 -15.7 3.7 245 32 17 7.3 4.0 37.9 100.2 9.1 M M
22000 -13.5 7.7 240 32 17 7.4 4.1 37.1 98.8 8.5 M M
21000 -11.5 11.3 240 31 16 6.7 3.6 36.0 96.8 7.6 M M
20000 -9.6 14.7 240 29 15 6.7 3.7 34.9 94.9 6.8 M M
19500 -8.1 17.4 235 28 14 6.6 3.6 34.2 93.5 6.2 M M
19000 -7.2 19.0 235 27 14 5.2 2.9 33.5 92.3 5.6 M M
18500 -6.5 20.3 235 25 13 5.3 2.9 32.7 90.9 4.9 M M
18000 -5.7 21.7 235 24 13 5.7 3.1 32.0 89.6 4.2 M M
17500 -4.9 23.2 235 23 12 5.9 3.2 31.3 88.4 3.6 M M
17000 -4.1 24.6 235 23 12 6.0 3.3 30.7 87.3 3.0 M M
16500 -3.2 26.2 235 22 11 6.4 3.5 30.1 86.2 2.4 M M
16000 -2.3 27.9 240 22 11 6.4 3.5 29.5 85.2 1.8 M M
15500 -1.4 29.5 240 21 11 6.3 3.5 29.0 84.2 1.3 M M
15000 -0.5 31.1 240 21 11 6.3 3.5 28.4 83.1 0.7 M M
14500 0.4 32.7 245 20 11 6.8 3.7 27.8 82.1 0.2 M M
14000 1.4 34.5 240 20 10 7.2 4.0 27.4 81.4 -0.3 721 3.7
13500 2.4 36.3 240 20 10 7.2 3.9 27.0 80.7 -0.7 675 3.4
13000 3.4 38.1 240 19 10 6.9 3.8 26.6 79.8 -1.1 630 3.2
12500 4.4 39.9 240 19 10 7.1 3.9 26.1 79.0 -1.6 586 3.0
12000 5.5 41.9 240 18 9 7.8 4.3 25.8 78.4 -2.0 539 2.7
11500 6.6 43.9 235 18 9 7.8 4.3 25.4 77.8 -2.4 492 2.5
11000 7.8 46.0 235 18 9 8.7 4.8 25.2 77.4 -2.7 441 2.2
10500 9.0 48.2 235 17 9 10.1 5.5 25.0 77.0 -2.9 389 2.0
10250 9.8 49.6 235 17 9 10.0 5.5 25.1 77.2 -2.8 358 1.8
10000 10.4 50.7 235 17 9 7.8 4.3 25.0 77.0 -3.0 333 1.7
9750 11.0 51.8 230 16 8 8.7 4.8 24.9 76.8 -3.1 307 1.6
9500 11.6 52.9 230 16 8 7.3 4.0 24.8 76.6 -3.2 281 1.4
9250 12.1 53.8 230 15 8 6.4 3.5 24.5 76.1 -3.5 260 1.3
9000 12.6 54.7 225 14 7 7.0 3.9 24.3 75.7 -3.7 238 1.2
8750 13.1 55.6 220 13 6 6.8 3.7 24.1 75.3 -4.0 216 1.1
8500 13.5 56.3 215 12 6 7.2 4.0 23.9 75.0 -4.2 194 1.0
8250 14.1 57.4 210 11 6 7.0 3.8 23.7 74.6 -4.4 171 0.9
8000 14.5 58.1 205 10 5 6.2 3.4 23.4 74.2 -4.7 150 0.8
7750 15.0 59.0 195 9 5 6.1 3.4 23.2 73.7 -5.0 129 0.7
7500 15.4 59.7 190 9 4 6.2 3.4 22.9 73.2 -5.3 109 0.6
7250 15.8 60.4 180 9 5 6.0 3.3 22.6 72.7 -5.7 89 0.5
7000 16.2 61.2 175 9 5 4.6 2.5 22.3 72.1 -6.0 71 0.4
6750 16.4 61.5 170 9 5 3.6 2.0 21.9 71.3 -6.5 55 0.3
6500 16.7 62.1 160 9 4 1.9 1.1 21.3 70.4 -7.0 42 0.2
6250 16.7 62.1 150 8 4 -0.0 -0.0 20.7 69.2 -7.7 33 0.2
6000 16.7 62.1 145 8 4 3.0 1.6 20.0 68.0 -8.4 24 0.1
5750 17.0 62.6 135 7 4 -0.1 -0.0 19.5 67.1 -9.0 11 0.1
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 * * * * * *
09/14/2026 AT 0900 MDT | 09/14/2026 AT 1200 MDT
|
CAPE... +699.1 LI... -2.3 | CAPE... +522.2 LI... -1.8
CINH... -43.1 K INDEX... +27.8 | CINH... -2.0 K INDEX... +23.0
|
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 -64.2 -83.6 240 45 23 2.4 1.3 | -63.6 -82.5 240 49 25 3.0 1.7
45000 -59.2 -74.6 240 66 34 5.4 3.0 | -58.4 -73.1 240 69 36 4.5 2.5
40000 -51.0 -59.8 235 74 38 6.1 3.4 | -51.4 -60.5 235 80 41 6.1 3.3
38000 -47.3 -53.1 235 74 38 6.1 3.4 | -47.8 -54.0 235 76 39 6.0 3.3
36000 -43.2 -45.8 235 73 38 6.1 3.4 | -43.8 -46.8 235 72 37 6.0 3.3
34000 -39.4 -38.9 235 66 34 6.3 3.5 | -39.9 -39.8 240 67 34 6.4 3.5
32000 -35.6 -32.1 240 59 30 6.2 3.4 | -36.1 -33.0 245 62 32 6.4 3.5
30000 -31.0 -23.8 240 55 28 8.1 4.4 | -31.4 -24.5 245 59 30 8.2 4.5
29000 -28.6 -19.5 245 54 28 8.1 4.4 | -28.9 -20.0 245 58 30 8.2 4.5
28000 -26.2 -15.2 245 53 28 8.0 4.4 | -26.5 -15.7 245 57 29 8.1 4.4
27000 -23.9 -11.0 245 52 27 7.6 4.2 | -24.1 -11.4 245 55 28 7.9 4.3
26000 -21.6 -6.9 245 51 26 7.6 4.2 | -21.8 -7.2 245 53 27 7.9 4.3
25000 -19.3 -2.7 245 50 26 7.7 4.2 | -19.4 -2.9 245 51 26 8.0 4.4
24000 -17.2 1.0 245 49 25 6.7 3.7 | -17.3 0.9 245 50 26 6.8 3.7
23000 -14.7 5.5 245 47 24 6.7 3.7 | -15.2 4.6 245 48 25 6.8 3.7
22000 -12.7 9.1 245 46 24 6.7 3.7 | -12.7 9.1 245 47 24 6.6 3.6
21000 -10.8 12.6 245 45 23 6.7 3.7 | -10.9 12.4 245 45 23 6.1 3.4
20000 -8.8 16.2 245 44 23 6.7 3.7 | -9.1 15.6 250 44 23 6.2 3.4
19500 -7.8 18.0 245 44 23 6.8 3.7 | -8.2 17.2 250 43 22 6.2 3.4
19000 -6.9 19.6 240 43 22 6.1 3.3 | -7.3 18.9 250 42 22 6.2 3.4
18500 -6.0 21.2 240 43 22 6.1 3.4 | -6.4 20.5 250 41 21 6.3 3.4
18000 -5.1 22.8 240 42 22 6.0 3.3 | -5.5 22.1 250 40 21 6.1 3.4
17500 -4.3 24.3 240 41 21 5.6 3.1 | -4.6 23.7 250 39 20 6.0 3.3
17000 -3.6 25.5 240 40 21 5.8 3.2 | -3.8 25.2 250 38 19 6.1 3.3
16500 -2.8 27.0 240 39 20 5.5 3.0 | -3.0 26.6 250 36 19 5.2 2.8
16000 -2.1 28.2 240 38 20 5.6 3.1 | -2.2 28.0 250 34 18 5.3 2.9
15500 -1.3 29.7 240 37 19 5.8 3.2 | -1.5 29.3 250 32 17 5.5 3.0
15000 -0.5 31.1 245 36 18 6.0 3.3 | -0.7 30.7 250 30 15 5.6 3.1
14500 0.3 32.5 245 34 18 6.2 3.4 | 0.0 32.0 250 28 14 6.0 3.3
14000 1.3 34.3 245 32 16 7.0 3.8 | 1.0 33.8 250 26 13 7.1 3.9
13500 2.3 36.1 245 30 15 7.0 3.8 | 1.9 35.4 250 25 13 7.1 3.9
13000 3.3 37.9 250 27 14 7.0 3.8 | 3.0 37.4 255 23 12 7.9 4.3
12500 4.3 39.7 250 25 13 7.0 3.8 | 4.1 39.4 255 22 11 7.8 4.3
12000 5.3 41.5 255 23 12 7.5 4.1 | 5.3 41.5 255 20 10 8.7 4.8
11500 6.4 43.5 255 22 11 7.5 4.1 | 6.5 43.7 255 19 10 8.6 4.7
11000 7.5 45.5 260 20 10 7.9 4.3 | 7.8 46.0 250 18 9 8.4 4.6
10500 8.6 47.5 260 20 10 7.5 4.1 | 9.0 48.2 250 17 9 8.5 4.7
10250 9.2 48.6 265 19 10 9.5 5.2 | 9.6 49.3 250 17 9 9.5 5.2
10000 9.9 49.8 260 18 9 10.0 5.5 | 10.3 50.5 245 16 8 9.5 5.2
9750 10.5 50.9 260 18 9 8.5 4.7 | 11.0 51.8 245 15 8 9.2 5.0
9500 11.2 52.2 260 17 9 8.5 4.7 | 11.6 52.9 245 14 7 8.9 4.9
9250 11.8 53.2 260 17 9 10.0 5.5 | 12.3 54.1 240 13 7 10.3 5.7
9000 12.6 54.7 260 18 9 9.1 5.0 | 13.1 55.6 245 13 7 10.1 5.5
8750 13.6 56.5 255 15 8 7.4 4.1 | 13.7 56.7 240 12 6 8.4 4.6
8500 14.1 57.4 250 14 7 7.5 4.1 | 14.3 57.7 240 12 6 8.8 4.8
8250 14.6 58.3 250 14 7 6.9 3.8 | 15.6 60.1 240 11 6 9.6 5.3
8000 15.0 59.0 245 13 7 5.6 3.1 | 16.4 61.5 240 10 5 9.9 5.4
7750 15.4 59.7 240 11 6 5.8 3.2 | 17.1 62.8 235 10 5 9.7 5.3
7500 15.8 60.4 230 10 5 6.7 3.7 | 17.7 63.9 235 9 5 8.8 4.8
7250 16.3 61.3 230 10 5 7.1 3.9 | 18.4 65.1 235 9 5 8.8 4.8
7000 16.8 62.2 220 9 5 6.3 3.5 | 19.1 66.4 235 9 4 10.3 5.7
6750 17.2 63.0 210 8 4 6.3 3.4 | 19.9 67.8 230 8 4 11.0 6.1
6500 17.7 63.9 200 7 4 6.7 3.7 | 20.7 69.3 230 8 4 11.0 6.0
6250 18.1 64.6 185 7 4 6.6 3.6 | 21.5 70.7 230 7 4 10.8 5.9
6000 18.6 65.5 175 7 4 6.5 3.6 | 22.3 72.1 230 7 4 9.9 5.4
5750 19.1 66.4 175 6 3 9.1 5.0 | 23.1 73.6 230 7 3 16.7 9.2
5500 20.1 68.2 160 5 3 21.3 11.7 | 25.4 77.7 230 6 3 56.1 30.8
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
09/14/2026 AT 1500 MDT | 09/14/2026 AT 1800 MDT
|
CAPE... +281.2 LI... -1.3 | CAPE... +520.7 LI... -2.0
CINH... -9.3 K INDEX... +27.4 | CINH... -20.4 K INDEX... +28.3
|
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 -63.5 -82.3 240 51 26 3.1 1.7 | -63.7 -82.7 245 53 27 3.1 1.7
45000 -58.5 -73.3 245 72 37 4.0 2.2 | -58.6 -73.5 245 73 37 3.8 2.1
40000 -52.2 -62.0 240 82 42 6.4 3.5 | -52.5 -62.5 240 81 42 6.7 3.7
38000 -48.3 -54.9 240 77 40 6.4 3.5 | -48.6 -55.5 240 77 40 6.6 3.6
36000 -44.1 -47.4 240 72 37 6.3 3.5 | -44.1 -47.4 240 73 38 6.6 3.6
34000 -40.2 -40.4 240 65 34 6.5 3.6 | -40.1 -40.2 245 67 34 6.7 3.7
32000 -36.2 -33.2 245 59 30 6.4 3.5 | -36.1 -33.0 245 61 31 6.6 3.6
30000 -31.4 -24.5 245 56 29 8.5 4.7 | -31.4 -24.5 245 57 29 8.2 4.5
29000 -28.8 -19.8 245 55 29 8.5 4.7 | -28.9 -20.0 250 55 28 8.2 4.5
28000 -26.3 -15.3 250 55 28 8.2 4.5 | -26.5 -15.7 250 54 28 8.1 4.4
27000 -24.0 -11.2 250 53 27 7.5 4.1 | -24.1 -11.4 250 52 27 7.8 4.3
26000 -21.8 -7.2 250 52 27 7.5 4.1 | -21.8 -7.2 250 50 26 7.8 4.3
25000 -19.6 -3.3 250 50 26 7.5 4.1 | -19.5 -3.1 255 48 25 7.9 4.3
24000 -17.4 0.7 250 49 25 7.4 4.1 | -17.2 1.0 255 46 24 7.6 4.1
23000 -15.1 4.8 250 48 25 7.4 4.1 | -14.9 5.2 255 45 23 7.6 4.1
22000 -12.4 9.7 250 46 24 6.6 3.6 | -12.1 10.2 255 42 22 6.7 3.7
21000 -10.8 12.6 250 43 22 5.3 2.9 | -10.5 13.1 255 40 20 5.3 2.9
20000 -9.2 15.4 250 40 21 5.3 2.9 | -9.0 15.8 255 37 19 5.4 3.0
19500 -8.4 16.9 250 39 20 5.3 2.9 | -8.3 17.1 260 36 19 5.6 3.1
19000 -7.6 18.3 250 37 19 5.7 3.1 | -7.5 18.5 260 35 18 4.5 2.5
18500 -6.8 19.8 250 36 18 5.7 3.1 | -6.9 19.6 260 33 17 4.7 2.6
18000 -6.0 21.2 250 34 17 6.0 3.3 | -6.3 20.7 255 31 16 5.2 2.8
17500 -5.2 22.6 250 32 17 6.3 3.5 | -5.4 22.3 255 30 15 5.8 3.2
17000 -4.3 24.3 250 31 16 6.4 3.5 | -4.6 23.7 255 28 15 5.7 3.1
16500 -3.4 25.9 250 29 15 6.5 3.6 | -3.7 25.3 255 27 14 7.6 4.2
16000 -2.5 27.5 250 27 14 6.6 3.6 | -2.6 27.3 255 26 13 7.5 4.1
15500 -1.6 29.1 250 26 13 7.1 3.9 | -1.5 29.3 255 25 13 8.2 4.5
15000 -0.6 30.9 245 24 13 7.3 4.0 | -0.3 31.5 255 24 12 8.6 4.7
14500 0.4 32.7 245 23 12 7.6 4.2 | 0.9 33.6 255 23 12 8.7 4.8
14000 1.6 34.9 245 22 11 8.2 4.5 | 2.2 36.0 250 22 11 9.0 4.9
13500 2.8 37.0 245 21 11 8.3 4.5 | 3.5 38.3 250 21 11 9.0 4.9
13000 4.0 39.2 245 20 10 8.9 4.9 | 4.8 40.6 250 20 10 9.1 5.0
12500 5.3 41.5 245 19 10 8.8 4.8 | 6.1 43.0 250 19 10 9.1 5.0
12000 6.6 43.9 240 19 10 9.4 5.2 | 7.5 45.5 250 18 9 9.3 5.1
11500 8.0 46.4 240 18 9 9.4 5.2 | 8.8 47.8 250 18 9 9.4 5.2
11000 9.4 48.9 240 17 9 8.9 4.9 | 10.1 50.2 250 17 9 7.8 4.3
10500 10.7 51.3 240 16 8 9.4 5.2 | 11.2 52.2 250 15 8 9.2 5.0
10250 11.4 52.5 240 16 8 10.3 5.7 | 12.0 53.6 250 15 8 11.6 6.4
10000 12.2 54.0 240 15 8 9.8 5.4 | 12.8 55.0 250 15 7 10.0 5.5
9750 12.9 55.2 240 15 8 9.6 5.2 | 13.5 56.3 250 14 7 8.7 4.8
9500 13.6 56.5 240 15 8 9.2 5.1 | 14.2 57.6 250 13 7 9.3 5.1
9250 14.3 57.7 240 15 8 10.8 5.9 | 14.8 58.6 245 13 7 8.3 4.6
9000 15.1 59.2 240 14 7 10.4 5.7 | 15.4 59.7 250 12 6 8.6 4.7
8750 15.8 60.4 240 14 7 8.7 4.8 | 16.1 61.0 250 11 6 9.6 5.2
8500 17.1 62.8 240 14 7 9.5 5.2 | 16.8 62.2 250 11 6 9.6 5.3
8250 17.8 64.0 245 13 7 10.0 5.5 | 18.0 64.4 250 10 5 8.6 4.7
8000 18.6 65.5 245 13 7 9.7 5.3 | 18.7 65.7 245 9 5 10.0 5.5
7750 19.3 66.7 240 13 7 9.8 5.4 | 19.5 67.1 245 9 5 9.7 5.3
7500 20.0 68.0 240 13 7 9.3 5.1 | 20.2 68.4 245 8 4 8.7 4.8
7250 20.7 69.3 245 12 6 9.3 5.1 | 20.8 69.4 245 8 4 8.4 4.6
7000 21.4 70.5 245 12 6 10.1 5.5 | 21.4 70.5 245 8 4 10.1 5.5
6750 22.2 72.0 245 12 6 10.7 5.9 | 22.2 72.0 245 7 4 10.5 5.7
6500 23.0 73.4 245 11 6 11.2 6.1 | 22.9 73.2 245 6 3 9.8 5.4
6250 23.8 74.8 245 11 6 11.7 6.4 | 23.7 74.7 240 6 3 10.1 5.5
6000 24.6 76.3 245 11 5 8.1 4.4 | 24.4 75.9 235 5 3 7.6 4.2
5750 25.2 77.4 245 10 5 11.8 6.5 | 24.8 76.6 245 5 3 6.9 3.8
5500 27.8 82.0 245 9 5 76.9 42.2 | 26.1 79.0 240 4 2 38.4 21.1
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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