367
UXUS97 KGJT 131306
SRGGJT
SOARING FORECAST
NATIONAL WEATHER SERVICE GRAND JUNCTION, COLORADO
706 AM MDT TUESDAY, OCTOBER 13, 2026
THIS FORECAST IS FOR TUESDAY, OCTOBER 13, 2026:
IF THE TRIGGER TEMPERATURE OF 53.7 F/12.1 C IS REACHED...THEN
THERMAL SOARING INDEX....................... POOR
MAXIMUM RATE OF LIFT........................ 6 FT/MIN (0.0 M/S)
MAXIMUM HEIGHT OF THERMALS.................. 11304 FT MSL (5696 FT AGL)
FORECAST MAXIMUM TEMPERATURE................... 59.0 F/15.5 C
TIME OF TRIGGER TEMPERATURE.................... 0900 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................. 9494 FT MSL (3886 FT AGL)
THERMAL SOARING OUTLOOK FOR WEDNESDAY 10/14.... POOR
WAVE SOARING INDEX............................. NOT AVAILABLE
REMARKS...
SUNRISE/SUNSET.................... 07:22:09 / 18:38:26 MDT
TOTAL POSSIBLE SUNSHINE........... 11 HR 16 MIN 17 SEC (676 MIN 17 SEC)
ALTITUDE OF SUN AT 13:00:17 MDT... 42.89 DEGREES
UPPER AIR DATA FROM RAWINSONDE OBSERVATION TAKEN ON 10/13/2026 AT 0600 MDT
FREEZING LEVEL.................. 9719 FT MSL (4111 FT AGL)
CONVECTIVE CONDENSATION LEVEL... 8721 FT MSL (3113 FT AGL)
LIFTED CONDENSATION LEVEL....... 10443 FT MSL (4835 FT AGL)
LIFTED INDEX.................... +0.7
K INDEX......................... +24.1
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 -58.1 -72.6 220 32 17 3.1 1.7 M M M M M
45000 -52.8 -63.0 215 39 20 4.5 2.5 M M M M M
40000 -46.1 -51.0 210 42 21 4.7 2.6 M M M M M
38000 -44.5 -48.1 210 49 25 2.3 1.2 M M M M M
36000 -43.1 -45.6 210 58 30 2.3 1.2 M M M M M
34000 -41.6 -42.9 205 66 34 3.1 1.7 M M M M M
32000 -39.7 -39.5 205 72 37 3.2 1.7 M M M M M
30000 -36.8 -34.2 200 77 40 6.6 3.6 39.3 102.7 18.4 M M
29000 -34.8 -30.6 200 77 40 6.6 3.6 38.0 100.3 17.6 M M
28000 -32.9 -27.2 200 78 40 6.6 3.6 36.8 98.3 16.9 M M
27000 -31.0 -23.8 195 77 40 4.5 2.5 35.5 96.0 16.1 M M
26000 -29.7 -21.5 200 72 37 4.6 2.5 33.5 92.2 14.6 M M
25000 -28.3 -18.9 200 68 35 4.6 2.5 31.5 88.8 13.3 M M
24000 -26.9 -16.4 200 63 33 5.5 3.0 29.8 85.6 12.0 M M
23000 -25.1 -13.2 195 53 27 6.4 3.5 28.4 83.2 10.9 M M
22000 -23.2 -9.8 190 43 22 6.4 3.5 27.2 81.0 10.0 M M
21000 -21.3 -6.3 185 34 18 7.9 4.3 26.2 79.1 9.2 M M
20000 -18.9 -2.0 185 34 17 8.1 4.5 25.5 78.0 8.7 M M
19500 -17.7 0.1 180 33 17 8.1 4.5 25.3 77.5 8.5 M M
19000 -16.5 2.3 180 33 17 8.1 4.5 25.0 77.0 8.3 M M
18500 -15.3 4.5 175 33 17 7.5 4.1 24.8 76.6 8.1 M M
18000 -13.8 7.2 175 32 16 7.0 3.9 24.1 75.3 7.5 M M
17500 -12.7 9.1 175 31 16 6.8 3.7 23.6 74.5 7.2 M M
17000 -11.8 10.8 170 30 16 6.6 3.6 23.1 73.5 6.7 M M
16500 -10.8 12.6 170 30 15 6.6 3.6 22.5 72.6 6.3 M M
16000 -9.9 14.2 165 28 15 6.2 3.4 22.0 71.5 5.7 M M
15500 -9.0 15.8 165 27 14 6.2 3.4 21.4 70.5 5.2 M M
15000 -8.1 17.4 165 26 13 6.0 3.3 20.8 69.4 4.7 M M
14500 -7.2 19.0 160 24 13 6.0 3.3 20.2 68.3 4.1 M M
14000 -6.4 20.5 160 23 12 5.7 3.1 19.5 67.2 3.5 M M
13500 -5.6 21.9 155 20 11 5.6 3.1 18.9 65.9 2.9 M M
13000 -4.8 23.4 150 18 9 5.5 3.0 18.2 64.7 2.3 M M
12500 -4.0 24.8 145 16 8 5.5 3.0 17.5 63.5 1.6 M M
12000 -3.2 26.2 135 14 7 5.4 3.0 16.8 62.3 1.0 M M
11500 -2.4 27.7 130 12 6 5.4 2.9 16.1 61.0 0.3 M M
11000 -1.6 29.1 115 10 5 4.7 2.6 15.4 59.8 -0.4 384 1.9
10500 -1.1 30.0 105 8 4 4.0 2.2 14.5 58.1 -1.3 352 1.8
10250 -0.8 30.6 100 8 4 4.9 2.7 14.1 57.4 -1.7 335 1.7
10000 -0.4 31.3 090 7 4 4.8 2.6 13.7 56.7 -2.1 317 1.6
9750 -0.1 31.8 080 7 3 4.2 2.3 13.3 55.9 -2.5 300 1.5
9500 0.2 32.4 070 6 3 4.2 2.3 12.9 55.2 -2.9 283 1.4
9250 0.5 32.9 065 6 3 5.0 2.7 12.5 54.4 -3.3 267 1.4
9000 0.9 33.6 055 6 3 6.0 3.3 12.1 53.9 -3.7 247 1.3
8750 1.4 34.5 045 6 3 6.0 3.3 11.8 53.3 -4.0 227 1.2
8500 1.8 35.2 040 6 3 5.8 3.2 11.6 52.8 -4.3 207 1.1
8250 2.2 36.0 030 6 3 6.6 3.6 11.3 52.3 -4.6 187 0.9
8000 2.7 36.9 025 6 3 6.8 3.7 11.1 51.9 -4.9 164 0.8
7750 3.2 37.8 020 6 3 6.2 3.4 10.8 51.4 -5.1 143 0.7
7500 3.6 38.5 015 6 3 6.5 3.6 10.5 51.0 -5.4 122 0.6
7250 4.1 39.4 005 6 3 5.7 3.1 10.3 50.5 -5.7 102 0.5
7000 4.5 40.1 350 5 3 5.9 3.2 9.9 49.9 -6.1 83 0.4
6750 4.9 40.8 345 5 3 7.0 3.8 9.7 49.5 -6.4 61 0.3
6500 5.4 41.7 335 5 3 5.7 3.1 9.5 49.0 -6.6 40 0.2
6250 5.7 42.3 325 5 3 3.0 1.7 9.1 48.3 -7.1 23 0.1
6000 5.9 42.6 310 5 3 4.3 2.4 8.6 47.4 -7.6 9 0.0
5750 6.4 43.5 305 5 2 10.3 5.7 8.4 47.1 -7.8 M M
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 * * * * * *
10/13/2026 AT 0900 MDT | 10/13/2026 AT 1200 MDT
|
CAPE... +154.6 LI... +0.7 | CAPE... +129.7 LI... -0.2
CINH... -6.8 K INDEX... +21.4 | CINH... -0.8 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 -59.3 -74.7 210 53 27 3.5 1.9 | -58.7 -73.7 215 49 25 3.6 2.0
45000 -53.2 -63.8 220 84 43 5.3 2.9 | -52.7 -62.9 220 74 38 4.5 2.5
40000 -45.3 -49.5 215 106 54 5.4 3.0 | -46.0 -50.8 215 106 54 4.5 2.5
38000 -42.7 -44.9 215 107 55 4.2 2.3 | -43.8 -46.8 215 104 53 3.5 1.9
36000 -40.2 -40.4 220 107 55 4.2 2.3 | -41.7 -43.1 220 100 52 3.5 1.9
34000 -38.2 -36.8 220 103 53 1.4 0.7 | -40.0 -40.0 220 96 49 2.1 1.2
32000 -37.4 -35.3 215 95 49 1.4 0.7 | -38.7 -37.7 215 91 47 2.1 1.2
30000 -35.8 -32.4 215 87 45 4.7 2.6 | -36.6 -33.9 215 87 45 6.2 3.4
29000 -34.5 -30.1 215 85 44 4.6 2.5 | -34.8 -30.6 220 86 44 6.2 3.4
28000 -33.1 -27.6 215 82 42 4.6 2.5 | -32.9 -27.2 220 86 44 6.2 3.4
27000 -31.6 -24.9 215 80 41 6.6 3.6 | -30.5 -22.9 220 85 44 6.5 3.6
26000 -29.5 -21.1 215 78 40 6.9 3.8 | -28.6 -19.5 220 85 44 6.5 3.5
25000 -27.5 -17.5 215 77 39 6.9 3.8 | -26.6 -15.9 220 85 44 6.5 3.6
24000 -25.4 -13.7 215 75 39 7.0 3.8 | -24.8 -12.6 220 84 43 5.1 2.8
23000 -23.3 -9.9 215 72 37 7.0 3.8 | -23.3 -9.9 220 79 41 4.8 2.6
22000 -21.2 -6.2 220 70 36 7.0 3.8 | -21.9 -7.4 220 74 38 4.9 2.7
21000 -18.8 -1.8 220 65 34 4.4 2.4 | -20.4 -4.7 215 67 35 6.5 3.6
20000 -17.5 0.5 220 60 31 4.7 2.6 | -18.5 -1.3 215 60 31 6.4 3.5
19500 -16.8 1.8 215 57 30 4.7 2.6 | -17.6 0.3 215 56 29 6.4 3.5
19000 -16.1 3.0 215 55 28 4.9 2.7 | -16.7 1.9 210 52 27 6.5 3.5
18500 -15.5 4.1 215 52 27 3.4 1.9 | -15.8 3.6 210 49 25 6.5 3.6
18000 -15.1 4.8 215 48 25 3.4 1.9 | -14.8 5.4 210 47 24 6.5 3.6
17500 -14.6 5.7 215 45 23 4.4 2.4 | -13.9 7.0 210 45 23 6.5 3.6
17000 -13.8 7.2 215 43 22 6.2 3.4 | -12.9 8.8 210 43 22 6.6 3.6
16500 -12.9 8.8 215 40 21 6.2 3.4 | -11.9 10.6 210 42 22 6.6 3.6
16000 -12.0 10.4 210 39 20 6.8 3.7 | -11.0 12.2 210 41 21 6.4 3.5
15500 -11.0 12.2 210 38 19 6.7 3.7 | -10.1 13.8 210 39 20 6.4 3.5
15000 -10.0 14.0 210 36 19 6.5 3.6 | -9.1 15.6 210 38 20 6.4 3.5
14500 -9.1 15.6 210 35 18 6.5 3.6 | -8.2 17.2 210 36 19 6.3 3.5
14000 -8.1 17.4 210 34 17 6.5 3.6 | -7.3 18.9 205 35 18 6.4 3.5
13500 -7.2 19.0 205 32 16 6.5 3.6 | -6.3 20.7 205 33 17 6.4 3.5
13000 -6.2 20.8 205 30 16 6.6 3.6 | -5.4 22.3 205 31 16 6.3 3.5
12500 -5.2 22.6 205 29 15 6.8 3.7 | -4.5 23.9 200 30 15 6.0 3.3
12000 -4.3 24.3 200 27 14 6.8 3.7 | -3.7 25.3 200 28 15 6.0 3.3
11500 -3.3 26.1 200 25 13 6.7 3.7 | -2.8 27.0 195 27 14 6.0 3.3
11000 -2.3 27.9 195 24 12 6.7 3.7 | -1.9 28.6 195 25 13 5.8 3.2
10500 -1.4 29.5 195 22 11 6.6 3.6 | -1.1 30.0 190 23 12 5.0 2.8
10250 -0.9 30.4 195 21 11 7.4 4.0 | -0.8 30.6 190 22 11 5.7 3.1
10000 -0.3 31.5 190 20 10 8.1 4.5 | -0.3 31.5 190 21 11 7.8 4.3
9750 0.3 32.5 190 19 10 7.4 4.0 | 0.3 32.5 190 20 10 7.3 4.0
9500 0.8 33.4 190 18 9 7.1 3.9 | 0.8 33.4 190 19 10 6.2 3.4
9250 1.3 34.3 190 17 9 7.3 4.0 | 1.2 34.2 185 18 9 6.3 3.5
9000 1.8 35.2 190 15 8 7.9 4.4 | 2.2 36.0 185 15 8 6.9 3.8
8750 2.4 36.3 185 14 7 7.4 4.1 | 2.6 36.7 185 14 7 6.1 3.4
8500 2.9 37.2 185 13 7 6.6 3.6 | 3.1 37.6 185 12 6 6.3 3.5
8250 3.4 38.1 185 12 6 6.8 3.7 | 3.6 38.5 185 11 6 6.4 3.5
8000 4.4 39.9 180 10 5 7.6 4.1 | 4.0 39.2 180 10 5 6.9 3.8
7750 4.9 40.8 175 8 4 7.8 4.3 | 4.6 40.3 185 9 5 7.4 4.1
7500 5.5 41.9 175 7 3 7.4 4.1 | 5.1 41.2 190 7 4 6.4 3.5
7250 6.0 42.8 170 6 3 6.9 3.8 | 5.5 41.9 190 6 3 4.6 2.5
7000 6.5 43.7 160 5 3 7.6 4.2 | 5.8 42.4 190 6 3 7.5 4.1
6750 7.1 44.8 160 4 2 8.2 4.5 | 6.5 43.7 200 4 2 9.8 5.4
6500 7.7 45.9 150 3 1 8.3 4.6 | 7.2 45.0 215 4 2 8.0 4.4
6250 8.3 46.9 145 3 1 8.8 4.8 | 7.7 45.9 225 3 2 7.2 3.9
6000 8.9 48.0 140 3 1 7.6 4.2 | 8.3 46.9 235 3 2 8.7 4.8
5750 9.4 48.9 120 1 1 6.3 3.5 | 9.1 48.4 240 3 1 13.3 7.3
5500 10.1 50.2 025 1 0 19.1 10.5 | 10.1 50.2 265 2 1 16.2 8.9
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
10/13/2026 AT 1500 MDT | 10/13/2026 AT 1800 MDT
|
CAPE... +22.4 LI... +0.1 | CAPE... +24.7 LI... +0.4
CINH... -10.1 K INDEX... +22.9 | CINH... -0.4 K INDEX... +22.0
|
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 -57.9 -72.2 215 45 23 3.4 1.9 | -57.5 -71.5 225 44 23 3.4 1.9
45000 -52.6 -62.7 220 61 31 4.0 2.2 | -52.5 -62.5 225 60 31 2.9 1.6
40000 -46.4 -51.5 220 86 44 4.3 2.4 | -48.0 -54.4 220 80 41 3.0 1.6
38000 -45.5 -49.9 220 90 46 1.2 0.6 | -46.8 -52.2 220 83 43 1.9 1.0
36000 -44.8 -48.6 220 94 48 1.2 0.6 | -45.7 -50.3 220 86 44 1.9 1.0
34000 -43.4 -46.1 220 94 49 4.2 2.3 | -43.8 -46.8 220 88 45 4.9 2.7
32000 -40.8 -41.4 220 91 47 4.2 2.3 | -40.9 -41.6 215 86 44 4.9 2.7
30000 -37.6 -35.7 220 88 45 7.5 4.1 | -37.4 -35.3 215 85 44 7.5 4.1
29000 -35.4 -31.7 220 87 45 7.5 4.1 | -35.1 -31.2 215 84 43 7.5 4.1
28000 -33.2 -27.8 220 86 44 7.5 4.1 | -32.9 -27.2 215 84 43 7.6 4.1
27000 -30.9 -23.6 220 85 44 7.3 4.0 | -30.6 -23.1 215 83 43 7.1 3.9
26000 -28.2 -18.8 220 84 43 7.3 4.0 | -28.5 -19.3 215 81 42 7.0 3.8
25000 -26.0 -14.8 220 82 42 7.3 4.0 | -25.9 -14.6 215 78 40 7.0 3.8
24000 -23.9 -11.0 220 81 41 4.5 2.5 | -23.9 -11.0 215 76 39 4.8 2.6
23000 -22.7 -8.9 220 75 39 4.3 2.4 | -22.5 -8.5 215 72 37 4.8 2.6
22000 -21.4 -6.5 215 70 36 4.3 2.4 | -21.1 -6.0 215 68 35 4.8 2.6
21000 -20.0 -4.0 215 64 33 6.3 3.4 | -19.6 -3.3 215 63 32 5.9 3.2
20000 -18.2 -0.8 215 57 29 6.2 3.4 | -17.9 -0.2 210 58 30 5.9 3.2
19500 -17.3 0.9 210 53 27 6.2 3.4 | -17.0 1.4 210 55 28 5.9 3.3
19000 -16.4 2.5 210 50 26 6.1 3.4 | -16.2 2.8 210 53 27 5.9 3.2
18500 -15.4 4.3 205 47 24 8.0 4.4 | -15.3 4.5 205 50 26 7.2 3.9
18000 -14.2 6.4 205 44 23 8.1 4.4 | -14.2 6.4 205 48 25 7.2 3.9
17500 -13.1 8.4 200 42 22 7.8 4.3 | -13.2 8.2 205 46 24 7.0 3.8
17000 -12.0 10.4 200 41 21 7.2 4.0 | -12.2 10.0 205 45 23 6.5 3.6
16500 -11.0 12.2 200 39 20 7.3 4.0 | -11.2 11.8 205 43 22 6.6 3.6
16000 -9.9 14.2 200 37 19 6.6 3.6 | -10.3 13.5 205 41 21 6.3 3.5
15500 -9.0 15.8 200 36 19 6.7 3.7 | -9.4 15.1 205 40 20 6.3 3.5
15000 -8.0 17.6 200 35 18 6.4 3.5 | -8.5 16.7 205 38 20 6.2 3.4
14500 -7.1 19.2 200 34 17 6.4 3.5 | -7.6 18.3 205 36 19 6.2 3.4
14000 -6.2 20.8 200 32 17 6.2 3.4 | -6.7 19.9 205 35 18 6.5 3.6
13500 -5.3 22.5 200 31 16 6.0 3.3 | -5.7 21.7 205 33 17 6.7 3.7
13000 -4.4 24.1 200 31 16 5.8 3.2 | -4.8 23.4 200 32 16 6.6 3.6
12500 -3.6 25.5 200 29 15 5.5 3.0 | -3.8 25.2 200 30 15 6.5 3.6
12000 -2.8 27.0 200 28 14 5.5 3.0 | -2.9 26.8 200 28 14 6.2 3.4
11500 -2.1 28.2 200 25 13 5.3 2.9 | -2.0 28.4 195 25 13 5.7 3.1
11000 -1.3 29.7 200 23 12 5.0 2.8 | -1.2 29.8 195 22 11 5.3 2.9
10500 -0.7 30.7 200 20 10 4.2 2.3 | -0.6 30.9 190 18 9 4.2 2.3
10250 -0.3 31.5 205 18 9 4.4 2.4 | -0.3 31.5 190 16 8 4.7 2.6
10000 -0.0 32.0 205 16 8 5.0 2.7 | 0.1 32.2 190 15 7 5.6 3.1
9750 0.4 32.7 205 15 8 4.9 2.7 | 0.5 32.9 190 13 7 5.2 2.9
9500 0.7 33.3 210 13 7 4.6 2.5 | 0.9 33.6 190 11 6 4.7 2.6
9250 1.0 33.8 215 12 6 4.5 2.5 | 1.2 34.2 190 9 5 4.8 2.6
9000 1.4 34.5 215 10 5 5.2 2.9 | 1.6 34.9 185 7 4 5.1 2.8
8750 2.2 36.0 225 8 4 4.9 2.7 | 1.9 35.4 175 6 3 5.3 2.9
8500 2.5 36.5 230 7 3 5.2 2.8 | 2.7 36.9 190 3 1 5.2 2.8
8250 2.9 37.2 240 6 3 5.7 3.1 | 3.1 37.6 205 1 1 4.9 2.7
8000 3.3 37.9 250 5 3 6.1 3.4 | 3.4 38.1 000 0 0 5.3 2.9
7750 3.8 38.8 260 5 2 6.4 3.5 | 3.9 39.0 330 2 1 6.0 3.3
7500 4.2 39.6 275 4 2 5.8 3.2 | 4.3 39.7 330 3 1 5.1 2.8
7250 4.6 40.3 290 4 2 4.4 2.4 | 4.6 40.3 340 4 2 3.6 2.0
7000 5.0 41.0 305 5 3 7.0 3.8 | 4.9 40.8 340 5 3 6.4 3.5
6750 5.6 42.1 310 5 2 9.0 4.9 | 5.5 41.9 340 5 3 8.4 4.6
6500 6.2 43.2 315 5 2 7.5 4.1 | 6.0 42.8 340 5 3 7.4 4.1
6250 6.7 44.1 320 6 3 6.4 3.5 | 6.6 43.9 335 6 3 6.8 3.7
6000 7.2 45.0 325 7 4 8.9 4.9 | 7.1 44.8 330 6 3 8.7 4.8
5750 8.0 46.4 315 5 2 14.8 8.1 | 7.9 46.2 335 4 2 13.0 7.1
5500 9.0 48.2 330 6 3 7.0 3.9 | 8.6 47.5 330 5 2 3.3 1.8
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.
042613
CLICK HERE TO GO TO PREVIOUS BULLETINS.
Main Text Page