720
UXUS97 KGJT 071306
SRGGJT
SOARING FORECAST
NATIONAL WEATHER SERVICE GRAND JUNCTION, COLORADO
706 AM MDT THURSDAY, AUGUST 7, 2025
THIS FORECAST IS FOR THURSDAY, AUGUST 7, 2025:
IF THE TRIGGER TEMPERATURE OF 84.7 F/29.3 C IS REACHED...THEN
THERMAL SOARING INDEX....................... EXCELLENT
MAXIMUM RATE OF LIFT........................ 1710 FT/MIN (8.7 M/S)
MAXIMUM HEIGHT OF THERMALS.................. 23324 FT MSL (17718 FT AGL)
FORECAST MAXIMUM TEMPERATURE................... 99.0 F/37.7 C
TIME OF TRIGGER TEMPERATURE.................... 0945 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................. 20313 FT MSL (14707 FT AGL)
THERMAL SOARING OUTLOOK FOR FRIDAY 08/08....... EXCELLENT
WAVE SOARING INDEX............................. NOT AVAILABLE
REMARKS...
SUNRISE/SUNSET.................... 06:20:39 / 20:19:04 MDT
TOTAL POSSIBLE SUNSHINE........... 13 HR 58 MIN 25 SEC (838 MIN 25 SEC)
ALTITUDE OF SUN AT 13:19:52 MDT... 66.66 DEGREES
UPPER AIR DATA FROM RAWINSONDE OBSERVATION TAKEN ON 08/07/2025 AT 0600 MDT
FREEZING LEVEL.................. 16147 FT MSL (10541 FT AGL)
CONVECTIVE CONDENSATION LEVEL... 20553 FT MSL (14947 FT AGL)
LIFTED CONDENSATION LEVEL....... 21991 FT MSL (16385 FT AGL)
LIFTED INDEX.................... -1.4
K INDEX......................... +13.2
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 -64.1 -83.4 255 36 19 -0.4 -0.2 M M M M M
45000 -62.4 -80.3 250 53 27 4.8 2.6 M M M M M
40000 -54.9 -66.8 245 52 27 7.2 3.9 M M M M M
38000 -50.6 -59.1 245 52 27 7.3 4.0 M M M M M
36000 -46.2 -51.2 250 51 26 7.2 3.9 M M M M M
34000 -40.7 -41.3 250 49 25 8.3 4.6 M M M M M
32000 -35.7 -32.3 255 48 25 8.9 4.9 M M M M M
30000 -30.9 -23.6 255 48 25 7.8 4.3 43.6 110.5 4.8 M M
29000 -28.6 -19.5 260 48 25 7.8 4.3 42.9 109.2 4.4 M M
28000 -26.3 -15.3 260 48 25 7.7 4.2 42.3 108.1 3.9 M M
27000 -24.0 -11.2 255 47 24 7.6 4.2 41.3 106.4 3.2 M M
26000 -21.7 -7.1 255 47 24 7.6 4.2 40.5 105.0 2.6 M M
25000 -19.4 -2.9 255 47 24 7.3 4.0 39.9 103.8 2.1 M M
24000 -17.6 0.3 250 47 24 5.8 3.2 38.4 101.2 0.9 M M
23000 -15.9 3.4 250 47 24 5.8 3.2 37.0 98.6 -0.3 1690 8.6
22000 -14.2 6.4 245 47 24 6.3 3.5 35.7 96.2 -1.4 1609 8.2
21000 -12.1 10.2 245 47 24 7.4 4.1 34.7 94.5 -2.3 1516 7.7
20000 -9.4 15.1 245 48 25 7.6 4.2 33.8 92.8 -3.3 1399 7.1
19500 -8.4 16.9 240 48 25 8.1 4.4 33.4 92.2 -3.7 1352 6.9
19000 -7.1 19.2 240 47 24 8.7 4.8 33.2 91.8 -3.9 1299 6.6
18500 -5.8 21.6 240 45 23 8.8 4.8 33.1 91.5 -4.1 1245 6.3
18000 -4.5 23.9 240 44 23 8.3 4.6 32.9 91.2 -4.3 1192 6.1
17500 -3.2 26.2 240 42 22 8.3 4.6 32.6 90.7 -4.5 1140 5.8
17000 -2.0 28.4 245 41 21 8.3 4.6 32.4 90.3 -4.8 1088 5.5
16500 -0.7 30.7 245 40 20 8.4 4.6 32.1 89.8 -5.0 1035 5.3
16000 0.5 32.9 245 38 20 8.4 4.6 31.9 89.5 -5.2 983 5.0
15500 1.8 35.2 245 36 19 8.1 4.5 31.7 89.0 -5.5 931 4.7
15000 3.0 37.4 245 35 18 8.1 4.5 31.4 88.5 -5.7 879 4.5
14500 4.2 39.6 245 33 17 8.8 4.8 31.2 88.1 -6.0 827 4.2
14000 5.5 41.9 245 32 17 8.9 4.9 31.0 87.9 -6.2 773 3.9
13500 6.8 44.2 250 31 16 9.0 4.9 30.9 87.6 -6.3 719 3.7
13000 8.2 46.8 250 30 16 9.1 5.0 30.8 87.4 -6.5 664 3.4
12500 9.5 49.1 250 29 15 9.1 5.0 30.7 87.2 -6.6 609 3.1
12000 10.9 51.6 250 28 14 9.0 4.9 30.6 87.0 -6.8 554 2.8
11500 12.2 54.0 250 27 14 8.8 4.8 30.4 86.8 -7.0 499 2.5
11000 13.5 56.3 250 26 13 8.0 4.4 30.2 86.4 -7.2 447 2.3
10500 14.8 58.6 250 25 13 10.3 5.7 30.1 86.2 -7.4 392 2.0
10250 15.6 60.1 250 25 13 9.6 5.2 30.1 86.2 -7.4 362 1.8
10000 16.2 61.2 250 25 13 8.4 4.6 30.0 86.1 -7.5 335 1.7
9750 16.9 62.4 250 24 12 9.2 5.1 30.0 85.9 -7.6 308 1.6
9500 17.5 63.5 245 24 12 7.1 3.9 29.9 85.8 -7.7 281 1.4
9250 18.0 64.4 245 23 12 7.1 3.9 29.6 85.3 -8.0 260 1.3
9000 18.6 65.5 245 22 11 9.1 5.0 29.5 85.2 -8.1 234 1.2
8750 19.3 66.7 245 21 11 8.9 4.9 29.5 85.0 -8.2 207 1.0
8500 19.9 67.8 240 20 10 7.8 4.3 29.4 84.9 -8.3 180 0.9
8250 20.4 68.7 240 19 10 6.5 3.5 29.2 84.5 -8.5 157 0.8
8000 20.9 69.6 235 18 9 6.7 3.7 28.9 84.0 -8.8 135 0.7
7750 21.4 70.5 230 16 8 6.7 3.7 28.7 83.6 -9.0 113 0.6
7500 21.9 71.4 225 14 7 6.6 3.6 28.5 83.2 -9.3 91 0.5
7250 22.3 72.1 220 12 6 5.6 3.1 28.2 82.7 -9.6 70 0.4
7000 22.7 72.9 215 11 5 3.9 2.1 27.8 82.0 -10.0 52 0.3
6750 22.9 73.2 205 9 5 2.6 1.4 27.3 81.1 -10.5 37 0.2
6500 23.0 73.4 190 8 4 -1.1 -0.6 26.7 80.0 -11.2 27 0.1
6250 22.7 72.9 180 8 4 -5.3 -2.9 25.6 78.2 -12.2 28 0.1
6000 22.5 72.5 165 9 4 2.7 1.5 24.7 76.4 -13.2 28 0.1
5750 22.7 72.9 155 8 4 -6.9 -3.8 24.1 75.5 -13.8 15 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 * * * * * *
08/07/2025 AT 0900 MDT | 08/07/2025 AT 1200 MDT
|
CAPE... 0.0 LI... +1.3 | CAPE... +3.3 LI... +0.9
CINH... -0.2 K INDEX... +20.7 | CINH... -15.7 K INDEX... +19.0
|
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 -65.1 -85.2 250 32 16 0.9 0.5 | -65.3 -85.5 250 34 18 0.2 0.1
45000 -62.0 -79.6 245 47 24 4.7 2.6 | -62.7 -80.9 245 50 26 5.2 2.8
40000 -53.8 -64.8 245 51 26 7.9 4.3 | -53.8 -64.8 245 50 26 8.0 4.4
38000 -49.0 -56.2 245 47 24 7.9 4.3 | -49.0 -56.2 245 46 23 8.0 4.4
36000 -44.3 -47.7 245 44 22 8.0 4.4 | -44.2 -47.6 245 41 21 7.9 4.3
34000 -39.4 -38.9 250 41 21 8.1 4.4 | -39.5 -39.1 245 41 21 7.9 4.3
32000 -34.6 -30.3 250 39 20 8.3 4.6 | -34.8 -30.6 245 40 21 8.1 4.5
30000 -29.9 -21.8 250 38 20 7.8 4.3 | -30.1 -22.2 250 40 20 7.8 4.3
29000 -27.5 -17.5 250 37 19 7.8 4.3 | -27.8 -18.0 250 39 20 7.8 4.3
28000 -25.3 -13.5 255 37 19 6.9 3.8 | -25.5 -13.9 250 39 20 7.1 3.9
27000 -23.2 -9.8 255 37 19 7.0 3.8 | -23.3 -9.9 255 38 20 7.2 3.9
26000 -21.1 -6.0 255 37 19 7.0 3.8 | -21.2 -6.2 255 37 19 7.2 3.9
25000 -19.0 -2.2 260 38 19 6.8 3.7 | -19.1 -2.4 260 37 19 6.9 3.8
24000 -16.6 2.1 255 37 19 6.4 3.5 | -16.6 2.1 255 37 19 6.5 3.6
23000 -14.7 5.5 255 37 19 6.4 3.5 | -14.7 5.5 255 38 20 6.5 3.6
22000 -12.8 9.0 250 37 19 6.6 3.6 | -12.7 9.1 250 39 20 6.9 3.8
21000 -10.9 12.4 250 39 20 6.7 3.7 | -10.7 12.7 250 40 21 7.0 3.8
20000 -8.9 16.0 245 41 21 6.9 3.8 | -8.7 16.3 245 41 21 7.0 3.9
19500 -8.0 17.6 245 42 21 7.4 4.1 | -7.7 18.1 245 42 22 7.6 4.2
19000 -6.9 19.6 245 42 22 7.7 4.2 | -6.5 20.3 245 41 21 7.9 4.4
18500 -5.8 21.6 245 42 22 7.8 4.3 | -5.3 22.5 245 41 21 8.0 4.4
18000 -4.6 23.7 240 42 22 8.9 4.9 | -4.2 24.4 245 40 21 7.9 4.3
17500 -3.4 25.9 240 41 21 8.8 4.8 | -3.0 26.6 240 39 20 7.9 4.3
17000 -2.1 28.2 240 41 21 8.6 4.7 | -1.8 28.8 240 38 19 8.5 4.6
16500 -0.8 30.6 240 39 20 8.5 4.6 | -0.5 31.1 240 36 18 8.7 4.8
16000 0.4 32.7 240 38 20 8.5 4.7 | 0.7 33.3 240 34 18 8.7 4.8
15500 1.7 35.1 240 37 19 8.6 4.7 | 2.0 35.6 240 32 17 8.6 4.7
15000 3.0 37.4 240 35 18 8.6 4.7 | 3.3 37.9 235 31 16 8.6 4.7
14500 4.4 39.9 240 34 17 8.6 4.7 | 4.6 40.3 235 29 15 9.2 5.0
14000 5.7 42.3 240 32 17 8.6 4.7 | 5.9 42.6 235 28 15 9.1 5.0
13500 7.0 44.6 240 31 16 8.7 4.8 | 7.3 45.1 235 27 14 9.2 5.1
13000 8.3 46.9 240 29 15 8.7 4.8 | 8.7 47.7 235 26 13 9.2 5.1
12500 9.6 49.3 240 27 14 8.9 4.9 | 10.0 50.0 235 25 13 9.3 5.1
12000 10.9 51.6 240 26 13 9.0 4.9 | 11.4 52.5 235 24 12 9.3 5.1
11500 12.3 54.1 240 24 12 9.0 4.9 | 12.8 55.0 235 23 12 9.3 5.1
11000 13.6 56.5 240 22 11 9.0 4.9 | 14.2 57.6 235 22 11 9.3 5.1
10500 14.9 58.8 240 20 10 8.6 4.7 | 15.6 60.1 235 21 11 8.4 4.6
10250 15.6 60.1 245 20 10 8.4 4.6 | 16.2 61.2 235 20 10 8.6 4.7
10000 16.2 61.2 240 19 10 8.8 4.8 | 16.9 62.4 235 19 10 10.1 5.5
9750 16.8 62.2 240 18 9 8.6 4.7 | 17.7 63.9 240 19 10 9.5 5.2
9500 17.5 63.5 240 17 9 9.1 5.0 | 18.4 65.1 240 18 9 10.5 5.8
9250 18.2 64.8 240 16 8 9.1 5.0 | 19.2 66.6 240 18 9 10.7 5.9
9000 18.8 65.8 240 16 8 7.7 4.2 | 19.9 67.8 240 17 9 9.1 5.0
8750 19.9 67.8 235 14 7 6.7 3.7 | 21.3 70.3 240 16 8 8.9 4.9
8500 20.3 68.5 235 13 7 5.9 3.2 | 21.9 71.4 245 16 8 8.4 4.6
8250 20.8 69.4 230 12 6 6.4 3.5 | 22.6 72.7 245 15 8 9.9 5.4
8000 21.3 70.3 225 11 5 6.5 3.6 | 23.4 74.1 245 15 8 11.3 6.2
7750 21.7 71.1 215 9 5 5.6 3.1 | 24.2 75.6 245 15 8 9.7 5.3
7500 22.1 71.8 210 9 5 4.9 2.7 | 24.8 76.6 245 15 8 8.5 4.7
7250 22.5 72.5 200 9 5 5.7 3.1 | 25.5 77.9 250 15 7 9.8 5.4
7000 22.9 73.2 195 9 4 7.2 3.9 | 26.3 79.3 250 14 7 11.8 6.5
6750 23.5 74.3 185 8 4 7.0 3.8 | 27.2 81.0 250 14 7 11.0 6.1
6500 24.0 75.2 175 8 4 6.5 3.6 | 28.0 82.4 250 13 7 10.9 6.0
6250 24.4 75.9 170 8 4 6.4 3.5 | 28.8 83.8 255 13 7 8.7 4.8
6000 25.0 77.0 170 7 3 10.5 5.7 | 29.5 85.1 250 12 6 15.4 8.4
5750 26.1 79.0 160 6 3 18.0 9.9 | 31.4 88.5 255 12 6 34.5 19.0
5500 27.1 80.8 155 6 3 4.4 2.4 | 33.4 92.1 255 11 6 4.1 2.2
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
08/07/2025 AT 1500 MDT | 08/07/2025 AT 1800 MDT
|
CAPE... +3.0 LI... +0.5 | CAPE... 0.0 LI... -0.1
CINH... -3.6 K INDEX... +14.9 | CINH... -0.2 K INDEX... +13.1
|
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 -65.2 -85.4 250 33 17 0.0 0.0 | -64.9 -84.8 255 32 17 0.8 0.5
45000 -62.8 -81.0 250 49 25 5.1 2.8 | -62.0 -79.6 255 47 24 4.4 2.4
40000 -53.9 -65.0 250 47 24 8.1 4.4 | -54.1 -65.4 255 47 24 8.1 4.5
38000 -49.1 -56.4 250 47 24 8.1 4.4 | -49.2 -56.6 255 47 24 8.1 4.5
36000 -44.3 -47.7 250 46 24 7.9 4.3 | -44.3 -47.7 255 46 24 7.9 4.3
34000 -39.6 -39.3 250 45 23 7.7 4.2 | -39.8 -39.6 255 46 24 7.6 4.2
32000 -35.0 -31.0 250 45 23 8.0 4.4 | -35.2 -31.4 250 47 24 7.9 4.3
30000 -30.4 -22.7 250 44 22 7.7 4.2 | -30.7 -23.3 250 45 23 7.5 4.1
29000 -28.1 -18.6 250 43 22 7.7 4.2 | -28.4 -19.1 250 45 23 7.5 4.1
28000 -25.9 -14.6 250 42 22 7.2 4.0 | -26.2 -15.2 250 44 22 7.7 4.2
27000 -23.7 -10.7 250 41 21 7.3 4.0 | -23.9 -11.0 250 42 22 7.7 4.2
26000 -21.5 -6.7 250 40 20 7.3 4.0 | -21.5 -6.7 250 41 21 7.7 4.2
25000 -18.8 -1.8 250 38 20 7.0 3.8 | -18.7 -1.7 245 40 20 7.1 3.9
24000 -16.7 1.9 250 38 20 7.0 3.8 | -16.6 2.1 250 38 20 7.1 3.9
23000 -14.6 5.7 250 38 20 7.0 3.8 | -14.5 5.9 250 37 19 7.1 3.9
22000 -12.5 9.5 245 38 19 7.2 3.9 | -12.4 9.7 250 36 19 7.1 3.9
21000 -10.5 13.1 245 37 19 7.2 4.0 | -10.3 13.5 245 34 18 7.2 3.9
20000 -8.4 16.9 240 37 19 7.3 4.0 | -8.2 17.2 245 33 17 7.3 4.0
19500 -7.3 18.9 240 37 19 8.2 4.5 | -7.2 19.0 245 32 16 8.4 4.6
19000 -6.0 21.2 240 36 19 8.6 4.7 | -5.8 21.6 245 31 16 9.1 5.0
18500 -4.7 23.5 240 35 18 8.6 4.7 | -4.5 23.9 245 31 16 9.1 5.0
18000 -3.4 25.9 235 34 18 9.0 4.9 | -3.1 26.4 240 30 16 9.3 5.1
17500 -2.1 28.2 235 33 17 8.9 4.9 | -1.7 28.9 240 30 15 9.3 5.1
17000 -0.8 30.6 235 32 17 9.2 5.1 | -0.3 31.5 240 29 15 9.5 5.2
16500 0.6 33.1 235 32 16 9.4 5.1 | 1.1 34.0 240 29 15 9.6 5.3
16000 2.0 35.6 235 31 16 9.4 5.1 | 2.5 36.5 240 29 15 9.6 5.3
15500 3.4 38.1 235 30 16 9.4 5.1 | 4.0 39.2 240 29 15 9.5 5.2
15000 4.8 40.6 235 30 15 9.4 5.1 | 5.4 41.7 240 28 15 9.6 5.2
14500 6.2 43.2 235 29 15 9.4 5.2 | 6.8 44.2 240 28 14 9.6 5.2
14000 7.6 45.7 235 29 15 9.4 5.2 | 8.2 46.8 240 28 14 9.6 5.2
13500 9.0 48.2 235 28 15 9.4 5.2 | 9.7 49.5 240 27 14 9.7 5.3
13000 10.4 50.7 235 28 14 9.4 5.2 | 11.1 52.0 240 27 14 9.7 5.3
12500 11.8 53.2 235 27 14 9.4 5.2 | 12.6 54.7 240 27 14 9.7 5.3
12000 13.2 55.8 240 27 14 9.4 5.2 | 14.0 57.2 240 26 14 9.5 5.2
11500 14.6 58.3 240 26 13 9.4 5.1 | 15.4 59.7 240 26 13 9.4 5.1
11000 16.0 60.8 240 25 13 9.2 5.0 | 16.8 62.2 240 25 13 9.0 5.0
10500 17.4 63.3 245 24 12 7.5 4.1 | 18.1 64.6 240 25 13 10.6 5.8
10250 17.9 64.2 245 24 12 8.3 4.5 | 19.0 66.2 240 25 13 11.1 6.1
10000 18.7 65.7 245 23 12 11.1 6.1 | 19.7 67.5 240 24 13 9.2 5.1
9750 19.5 67.1 245 23 12 10.4 5.7 | 20.4 68.7 240 24 12 9.6 5.3
9500 20.2 68.4 245 23 12 10.2 5.6 | 21.2 70.2 240 24 12 9.8 5.4
9250 21.0 69.8 245 23 12 9.7 5.3 | 21.9 71.4 245 23 12 10.0 5.5
9000 21.7 71.1 245 23 12 9.9 5.4 | 22.6 72.7 245 23 12 9.6 5.2
8750 23.2 73.8 250 22 12 9.5 5.2 | 24.1 75.4 245 22 11 9.3 5.1
8500 23.9 75.0 250 22 11 8.5 4.7 | 24.7 76.5 245 22 11 8.6 4.7
8250 24.5 76.1 250 22 11 10.1 5.5 | 25.4 77.7 245 22 11 9.6 5.3
8000 25.4 77.7 250 22 11 11.9 6.5 | 26.2 79.2 245 21 11 10.9 6.0
7750 26.2 79.2 250 21 11 9.9 5.4 | 27.0 80.6 245 21 11 9.7 5.3
7500 26.9 80.4 250 21 11 7.9 4.3 | 27.6 81.7 245 21 11 8.1 4.5
7250 27.5 81.5 250 21 11 9.8 5.4 | 28.3 82.9 245 21 11 9.2 5.0
7000 28.3 82.9 250 21 11 12.6 6.9 | 29.0 84.2 245 20 10 11.5 6.3
6750 29.3 84.7 250 20 10 11.5 6.3 | 29.9 85.8 245 19 10 11.1 6.1
6500 30.1 86.2 255 19 10 10.6 5.8 | 30.7 87.3 245 19 10 10.2 5.6
6250 30.9 87.6 255 19 10 9.2 5.0 | 31.4 88.5 245 19 10 9.9 5.4
6000 31.6 88.9 255 18 9 14.2 7.8 | 32.2 90.0 245 18 9 10.5 5.7
5750 33.3 91.9 255 17 9 31.0 17.0 | 33.1 91.6 245 16 8 16.6 9.1
5500 35.5 95.9 255 16 8 20.7 11.4 | 34.7 94.5 245 14 7 26.0 14.3
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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