312  
UXUS97 KGJT 191237  
SRGGJT  
 
SOARING FORECAST  
NATIONAL WEATHER SERVICE GRAND JUNCTION, COLORADO  
0637 MDT SATURDAY, AUGUST 19, 2017  
 
THIS FORECAST IS FOR SATURDAY, AUGUST 19, 2017:  
 
IF THE TRIGGER TEMPERATURE OF 87.4 F/30.8 C IS REACHED...THEN  
THERMAL SOARING INDEX....................... EXCELLENT  
MAXIMUM RATE OF LIFT........................ 1511 FT/MIN (7.7 M/S)  
MAXIMUM HEIGHT OF THERMALS.................. 20261 FT MSL (15422 FT AGL)  
 
FORECAST MAXIMUM TEMPERATURE................... 95.0 F/35.5 C  
TIME OF TRIGGER TEMPERATURE.................... 1115 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................. 11738 FT MSL (6899 FT AGL)  
THERMAL SOARING OUTLOOK FOR SUNDAY 08/20....... EXCELLENT  
 
WAVE SOARING INDEX............................. NOT AVAILABLE  
 
REMARKS...  
 
SUNRISE/SUNSET.................... 06:31:17 / 20:04:32 MDT  
TOTAL POSSIBLE SUNSHINE........... 13 HR 33 MIN 16 SEC (813 MIN 16 SEC)  
ALTITUDE OF SUN AT 13:17:33 MDT... 63.39 DEGREES  
 
UPPER AIR DATA FROM RAWINSONDE OBSERVATION TAKEN ON 08/19/2017 AT 0600 MDT  
 
FREEZING LEVEL.................. 15550 FT MSL (10711 FT AGL)  
CONVECTIVE CONDENSATION LEVEL... 18370 FT MSL (13531 FT AGL)  
LIFTED CONDENSATION LEVEL....... 19268 FT MSL (14429 FT AGL)  
LIFTED INDEX.................... -0.9  
K INDEX......................... +21.3  
 
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 -64.7 -84.5 265 36 18 1.1 0.6 87.9 190.2 30.5 M M  
45000 -62.3 -80.1 255 52 27 4.5 2.5 66.1 151.0 19.3 M M  
40000 -53.8 -64.8 255 46 24 6.5 3.6 56.7 134.0 14.4 M M  
38000 -50.1 -58.2 250 50 26 5.5 3.0 53.4 128.1 12.6 M M  
36000 -47.1 -52.8 250 40 21 5.4 3.0 49.3 120.7 10.0 M M  
34000 -42.4 -44.3 255 35 18 8.4 4.6 47.5 117.5 9.0 M M  
32000 -36.7 -34.1 260 30 16 8.4 4.6 46.5 115.6 8.5 M M  
30000 -31.9 -25.4 260 27 14 6.6 3.6 45.1 113.2 7.7 M M  
29000 -30.2 -22.4 260 21 11 7.2 3.9 43.5 110.4 6.5 M M  
28000 -27.7 -17.9 260 16 8 6.2 3.4 42.9 109.3 6.2 M M  
27000 -25.9 -14.6 255 11 6 6.3 3.4 41.6 106.9 5.2 M M  
26000 -23.7 -10.7 225 10 5 8.4 4.6 40.6 105.1 4.5 M M  
25000 -21.2 -6.2 235 11 6 8.3 4.6 40.2 104.3 4.1 M M  
24000 -18.8 -1.8 240 9 5 7.8 4.3 39.4 102.9 3.5 M M  
23000 -16.5 2.3 240 7 3 7.8 4.3 38.7 101.6 3.0 M M  
22000 -14.2 6.4 245 4 2 7.8 4.3 38.1 100.6 2.5 M M  
21000 -11.9 10.6 250 8 4 6.6 3.6 37.3 99.1 1.9 M M  
20000 -11.3 11.7 250 12 6 4.8 2.6 34.6 94.3 -0.5 1505 7.6  
19500 -10.3 13.5 270 13 7 5.3 2.9 34.2 93.5 -0.9 1459 7.4  
19000 -9.6 14.7 285 16 8 8.6 4.7 33.4 92.2 -1.7 1424 7.2  
18500 -8.2 17.2 285 15 8 9.3 5.1 33.4 92.1 -1.8 1367 6.9  
18000 -6.8 19.8 280 14 7 9.3 5.1 33.3 92.0 -1.8 1310 6.7  
17500 -4.7 23.5 275 13 6 9.3 5.1 33.2 91.7 -2.0 1226 6.2  
17000 -3.4 25.9 275 12 6 9.5 5.2 33.1 91.6 -2.1 1170 5.9  
16500 -2.2 28.0 270 11 6 6.7 3.7 32.9 91.2 -2.4 1120 5.7  
16000 -1.1 30.0 265 10 5 9.9 5.5 32.6 90.7 -2.7 1072 5.4  
15500 0.4 32.7 265 11 5 9.8 5.4 32.6 90.7 -2.8 1013 5.1  
15000 1.9 35.4 265 11 6 9.8 5.4 32.6 90.8 -2.8 954 4.8  
14500 3.3 37.9 265 12 6 9.8 5.4 32.7 90.8 -2.7 896 4.5  
14000 4.8 40.6 265 12 6 9.8 5.4 32.7 90.9 -2.7 837 4.3  
13500 6.3 43.3 270 12 6 9.8 5.4 32.7 90.9 -2.8 778 4.0  
13000 7.7 45.9 270 11 6 9.8 5.4 32.7 90.9 -2.8 719 3.7  
12500 9.2 48.6 275 11 6 9.5 5.2 32.7 90.9 -2.8 661 3.4  
12000 10.5 50.9 280 11 6 9.0 4.9 32.6 90.7 -2.9 606 3.1  
11500 11.8 53.2 280 10 5 9.0 4.9 32.5 90.4 -3.1 552 2.8  
11000 13.1 55.6 275 8 4 9.0 4.9 32.3 90.2 -3.3 498 2.5  
10500 14.5 58.1 270 7 4 8.8 4.8 32.2 90.0 -3.4 444 2.3  
10250 15.1 59.2 270 7 3 8.4 4.6 32.1 89.8 -3.5 417 2.1  
10000 15.7 60.3 265 6 3 8.4 4.6 32.0 89.6 -3.6 391 2.0  
9750 16.4 61.5 260 5 3 8.4 4.6 31.9 89.5 -3.7 364 1.8  
9500 17.0 62.6 255 5 3 8.4 4.6 31.8 89.3 -3.8 338 1.7  
9250 17.6 63.7 250 4 2 8.4 4.6 31.7 89.1 -3.9 311 1.6  
9000 18.3 64.9 240 4 2 8.4 4.6 31.6 88.9 -4.0 285 1.4  
8750 18.9 66.0 240 4 2 8.4 4.6 31.5 88.7 -4.1 258 1.3  
8500 19.6 67.3 240 4 2 8.4 4.6 31.4 88.5 -4.2 232 1.2  
8250 20.2 68.4 245 3 2 8.2 4.5 31.3 88.3 -4.3 205 1.0  
8000 20.8 69.4 245 3 2 8.8 4.9 31.2 88.1 -4.4 179 0.9  
7750 21.5 70.7 210 4 2 6.6 3.6 31.1 87.9 -4.5 152 0.8  
7500 21.7 71.1 195 7 3 -0.4 -0.2 30.6 87.0 -5.0 138 0.7  
7250 21.5 70.7 185 10 5 -3.3 -1.8 29.6 85.3 -6.0 137 0.7  
7000 21.2 70.2 180 12 6 -2.5 -1.4 28.7 83.6 -7.0 137 0.7  
6750 21.0 69.8 170 13 7 -2.7 -1.5 27.7 81.9 -7.9 136 0.7  
6500 20.8 69.4 160 14 7 -2.6 -1.4 26.8 80.2 -8.9 135 0.7  
6250 20.6 69.1 155 16 8 -2.6 -1.4 25.8 78.5 -9.9 135 0.7  
6000 20.5 68.9 145 17 9 3.2 1.7 25.0 77.1 -10.7 130 0.7  
5750 20.9 69.6 140 16 8 6.6 3.6 24.8 76.6 -11.0 109 0.6  
5500 21.4 70.5 135 13 7 7.8 4.3 24.5 76.1 -11.3 88 0.4  
5250 21.8 71.2 130 11 6 -0.4 -0.2 24.2 75.6 -11.6 68 0.3  
5000 20.8 69.4 120 9 5 -28.6 -15.7 22.5 72.5 -13.5 92 0.5  
 
* * * * * * NUMERICAL WEATHER PREDICTION MODEL FORECAST DATA VALID * * * * * *  
 
08/19/2017 AT 0900 MDT | 08/19/2017 AT 1200 MDT  
|  
K INDEX... +22.3 LI... -0.7 | K INDEX... +22.0 LI... -0.8  
CAPE... +13.5 CIN... -22.9 | CAPE... +32.1 CIN... -34.9  
|  
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 -63.2 -81.8 265 30 16 0.3 0.2 | -63.0 -81.4 265 29 15 0.5 0.3  
45000 -60.9 -77.6 265 40 21 4.4 2.4 | -60.5 -76.9 265 40 21 4.4 2.4  
40000 -54.0 -65.2 260 40 20 5.8 3.2 | -53.8 -64.8 255 41 21 5.6 3.0  
38000 -50.5 -58.9 260 36 19 5.9 3.2 | -50.4 -58.7 255 37 19 5.6 3.1  
36000 -47.0 -52.6 260 33 17 5.7 3.1 | -47.1 -52.8 255 33 17 5.4 3.0  
34000 -42.3 -44.1 260 32 16 8.4 4.6 | -42.4 -44.3 255 32 17 8.2 4.5  
32000 -37.2 -35.0 260 31 16 8.3 4.6 | -37.5 -35.5 255 32 16 8.1 4.5  
30000 -32.0 -25.6 260 26 13 7.6 4.2 | -32.3 -26.1 255 28 14 7.6 4.2  
29000 -29.7 -21.5 260 23 12 7.7 4.2 | -30.0 -22.0 260 25 13 7.6 4.2  
28000 -27.5 -17.5 260 20 10 7.4 4.1 | -27.8 -18.0 260 23 12 7.4 4.1  
27000 -25.3 -13.5 265 18 9 7.4 4.1 | -25.6 -14.1 260 19 10 7.4 4.1  
26000 -23.0 -9.4 265 16 8 7.4 4.1 | -23.3 -9.9 265 15 8 7.5 4.1  
25000 -20.8 -5.4 270 13 7 7.1 3.9 | -21.1 -6.0 265 12 6 7.2 4.0  
24000 -18.9 -2.0 265 13 7 6.4 3.5 | -19.1 -2.4 265 11 6 6.5 3.6  
23000 -17.0 1.4 260 13 6 6.4 3.5 | -17.2 1.0 265 11 6 6.5 3.6  
22000 -15.0 5.0 260 12 6 6.4 3.5 | -15.2 4.6 265 11 6 6.6 3.6  
21000 -13.1 8.4 255 12 6 6.5 3.6 | -13.3 8.1 255 13 7 6.8 3.7  
20000 -11.3 11.7 250 13 7 6.6 3.6 | -11.3 11.7 250 15 8 6.8 3.8  
19500 -10.3 13.5 250 13 7 6.7 3.7 | -10.3 13.5 245 16 8 6.9 3.8  
19000 -9.2 15.4 250 13 7 8.7 4.7 | -9.2 15.4 245 17 9 8.8 4.8  
18500 -8.0 17.6 250 13 7 8.5 4.7 | -7.9 17.8 245 17 9 8.7 4.8  
18000 -6.7 19.9 245 14 7 8.5 4.7 | -6.6 20.1 250 18 9 8.6 4.7  
17500 -5.5 22.1 250 13 7 8.5 4.7 | -5.3 22.5 250 18 9 8.6 4.7  
17000 -4.3 24.3 250 12 6 8.6 4.7 | -4.0 24.8 250 17 9 8.6 4.7  
16500 -3.0 26.6 255 11 6 8.5 4.6 | -2.8 27.0 250 17 8 8.6 4.7  
16000 -1.8 28.8 260 10 5 8.4 4.6 | -1.5 29.3 250 16 8 8.6 4.7  
15500 -0.5 31.1 265 10 5 9.2 5.1 | -0.2 31.6 255 15 8 9.1 5.0  
15000 0.9 33.6 265 10 5 9.3 5.1 | 1.1 34.0 255 14 7 9.2 5.1  
14500 3.0 37.4 270 10 5 9.6 5.3 | 3.1 37.6 255 13 7 9.0 5.0  
14000 4.4 39.9 270 10 5 9.6 5.3 | 4.4 39.9 260 12 6 9.1 5.0  
13500 5.9 42.6 270 10 5 9.4 5.2 | 5.8 42.4 260 12 6 9.2 5.0  
13000 7.3 45.1 270 11 5 9.4 5.1 | 7.1 44.8 260 11 6 9.2 5.0  
12500 8.7 47.7 270 11 6 9.4 5.1 | 8.5 47.3 265 11 6 9.6 5.3  
12000 10.0 50.0 270 11 6 9.4 5.1 | 9.9 49.8 265 11 6 9.7 5.3  
11500 11.4 52.5 270 11 6 9.3 5.1 | 11.4 52.5 270 11 6 9.6 5.3  
11000 12.8 55.0 270 11 6 9.1 5.0 | 12.8 55.0 270 11 6 9.5 5.2  
10500 14.1 57.4 270 12 6 4.3 2.3 | 14.1 57.4 270 11 5 5.5 3.0  
10250 14.3 57.7 270 11 6 5.6 3.1 | 14.4 57.9 275 10 5 7.6 4.2  
10000 15.0 59.0 270 11 6 11.7 6.4 | 15.3 59.5 275 10 5 11.8 6.5  
9750 15.8 60.4 270 11 6 10.4 5.7 | 16.1 61.0 275 10 5 10.9 6.0  
9500 16.5 61.7 270 11 6 8.0 4.4 | 16.9 62.4 275 9 5 7.8 4.3  
9250 16.9 62.4 270 11 6 6.0 3.3 | 17.3 63.1 275 9 5 6.6 3.6  
9000 17.5 63.5 270 10 5 7.5 4.1 | 17.9 64.2 275 8 4 9.0 4.9  
8750 18.0 64.4 270 10 5 7.3 4.0 | 18.6 65.5 275 8 4 8.5 4.7  
8500 18.5 65.3 265 9 4 5.0 2.8 | 19.1 66.4 275 7 4 6.7 3.7  
8250 18.8 65.8 260 7 4 3.5 1.9 | 19.6 67.3 270 6 3 5.7 3.1  
8000 19.1 66.4 250 6 3 3.9 2.2 | 20.0 68.0 260 5 2 6.6 3.6  
7750 19.5 67.1 235 5 3 3.9 2.1 | 20.6 69.1 250 4 2 7.8 4.3  
7500 19.8 67.6 215 5 2 4.3 2.3 | 21.2 70.2 240 3 2 9.1 5.0  
7250 20.1 68.2 200 5 3 4.1 2.2 | 21.9 71.4 240 3 2 9.7 5.3  
7000 20.4 68.7 190 6 3 5.1 2.8 | 22.6 72.7 235 3 2 9.3 5.1  
6750 20.8 69.4 180 7 4 3.2 1.8 | 23.3 73.9 235 3 2 10.3 5.6  
6500 20.8 69.4 175 7 3 0.3 0.2 | 24.2 75.6 235 3 2 11.3 6.2  
6250 20.8 69.4 165 6 3 0.6 0.3 | 25.0 77.0 235 3 2 11.4 6.3  
6000 20.9 69.6 160 6 3 0.5 0.3 | 25.8 78.4 235 3 2 10.5 5.8  
5750 21.0 69.8 150 5 3 5.4 2.9 | 26.6 79.9 235 3 2 12.6 6.9  
5500 21.6 70.9 150 5 2 9.8 5.4 | 27.7 81.9 235 3 2 15.7 8.6  
5250 22.2 72.0 145 4 2 6.4 3.5 | 28.8 83.8 235 3 2 13.3 7.3  
5000 M M M M M M M | M M M M M M M  
 
08/19/2017 AT 1500 MDT | 08/19/2017 AT 1800 MDT  
|  
K INDEX... +23.0 LI... -0.0 | K INDEX... +20.5 LI... +0.8  
CAPE... +22.3 CIN... -70.6 | CAPE... +2.4 CIN... -10.6  
|  
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 -63.4 -82.1 265 31 16 0.9 0.5 | -64.1 -83.4 260 35 18 1.6 0.9  
45000 -60.3 -76.5 260 39 20 4.5 2.5 | -60.4 -76.7 260 42 22 4.3 2.4  
40000 -53.4 -64.1 260 42 22 5.7 3.1 | -53.6 -64.5 255 43 22 6.1 3.4  
38000 -49.9 -57.8 260 38 20 5.7 3.1 | -49.9 -57.8 255 39 20 6.2 3.4  
36000 -46.5 -51.7 255 34 18 5.6 3.1 | -46.2 -51.2 255 36 18 6.1 3.3  
34000 -42.1 -43.8 255 34 17 7.6 4.2 | -41.7 -43.1 260 35 18 7.7 4.2  
32000 -37.0 -34.6 255 34 17 7.7 4.2 | -37.1 -34.8 265 34 18 7.6 4.2  
30000 -32.3 -26.1 260 30 15 7.9 4.3 | -31.8 -25.2 265 30 16 7.9 4.4  
29000 -29.9 -21.8 260 28 14 7.9 4.3 | -29.4 -20.9 265 28 14 8.0 4.4  
28000 -27.6 -17.7 260 25 13 7.0 3.8 | -27.1 -16.8 265 26 13 6.9 3.8  
27000 -25.6 -14.1 260 22 11 6.9 3.8 | -25.0 -13.0 265 23 12 6.8 3.7  
26000 -23.5 -10.3 260 18 10 7.0 3.8 | -23.0 -9.4 265 21 11 6.8 3.7  
25000 -21.5 -6.7 260 15 8 7.3 4.0 | -21.0 -5.8 260 18 9 6.9 3.8  
24000 -19.2 -2.6 260 13 7 7.7 4.2 | -18.8 -1.8 260 17 9 7.3 4.0  
23000 -16.9 1.6 255 12 6 7.7 4.2 | -16.6 2.1 260 16 8 7.4 4.1  
22000 -14.6 5.7 255 10 5 7.5 4.1 | -14.5 5.9 255 15 7 7.5 4.1  
21000 -12.4 9.7 250 13 6 7.4 4.0 | -12.3 9.9 250 17 9 7.5 4.1  
20000 -10.3 13.5 245 15 8 7.4 4.1 | -10.1 13.8 250 19 10 7.6 4.2  
19500 -9.2 15.4 240 16 8 7.4 4.1 | -9.0 15.8 250 21 11 7.6 4.2  
19000 -8.0 17.6 240 17 9 9.1 5.0 | -7.9 17.8 250 21 11 8.5 4.7  
18500 -6.7 19.9 240 17 9 9.0 4.9 | -6.6 20.1 245 21 11 8.5 4.7  
18000 -5.4 22.3 245 17 9 8.3 4.6 | -5.4 22.3 245 21 11 8.5 4.6  
17500 -4.3 24.3 245 17 9 7.8 4.3 | -4.2 24.4 245 20 10 8.4 4.6  
17000 -3.2 26.2 245 16 8 7.8 4.3 | -3.0 26.6 250 19 10 8.4 4.6  
16500 -2.0 28.4 250 16 8 8.1 4.5 | -1.7 28.9 250 18 9 9.2 5.0  
16000 -0.8 30.6 250 15 8 8.1 4.4 | -0.3 31.5 250 17 9 9.1 5.0  
15500 0.4 32.7 250 15 8 8.5 4.7 | 1.0 33.8 250 16 8 8.9 4.9  
15000 2.3 36.1 255 15 7 8.6 4.7 | 2.3 36.1 250 16 8 8.9 4.9  
14500 3.6 38.5 255 14 7 8.8 4.8 | 4.3 39.7 255 15 8 8.7 4.8  
14000 5.0 41.0 255 14 7 8.8 4.8 | 5.6 42.1 260 14 7 8.7 4.8  
13500 6.3 43.3 260 14 7 8.9 4.9 | 7.0 44.6 260 14 7 8.7 4.8  
13000 7.6 45.7 260 13 7 8.9 4.9 | 8.3 46.9 265 13 7 8.8 4.8  
12500 8.9 48.0 260 12 6 9.0 4.9 | 9.6 49.3 265 12 6 8.7 4.8  
12000 10.3 50.5 265 11 6 9.0 4.9 | 10.9 51.6 270 12 6 8.7 4.8  
11500 11.7 53.1 265 10 5 8.8 4.8 | 12.2 54.0 275 11 6 8.5 4.7  
11000 12.9 55.2 265 9 5 8.4 4.6 | 13.5 56.3 275 11 6 8.1 4.5  
10500 14.2 57.6 265 8 4 5.4 2.9 | 14.7 58.5 280 11 5 5.6 3.1  
10250 14.5 58.1 265 8 4 7.0 3.8 | 15.0 59.0 285 10 5 6.6 3.6  
10000 15.3 59.5 265 8 4 12.0 6.6 | 15.8 60.4 285 10 5 10.6 5.8  
9750 16.1 61.0 265 8 4 11.4 6.3 | 16.5 61.7 290 10 5 10.1 5.5  
9500 16.9 62.4 260 7 4 8.2 4.5 | 17.3 63.1 290 10 5 8.1 4.5  
9250 17.4 63.3 260 7 4 7.6 4.2 | 17.8 64.0 295 9 5 7.1 3.9  
9000 18.2 64.8 260 7 4 11.0 6.0 | 18.4 65.1 295 9 4 8.8 4.8  
8750 18.9 66.0 260 7 4 10.4 5.7 | 19.0 66.2 295 8 4 8.3 4.6  
8500 19.7 67.5 260 7 4 10.4 5.7 | 19.6 67.3 300 8 4 9.4 5.2  
8250 20.5 68.9 260 7 4 10.1 5.5 | 20.4 68.7 300 8 4 10.1 5.6  
8000 21.2 70.2 260 7 4 9.1 5.0 | 21.1 70.0 295 8 4 9.2 5.1  
7750 21.9 71.4 260 7 4 8.9 4.9 | 21.7 71.1 295 8 4 8.9 4.9  
7500 22.6 72.7 260 7 4 10.3 5.6 | 22.4 72.3 295 8 4 9.7 5.3  
7250 23.4 74.1 255 7 4 11.2 6.2 | 23.2 73.8 295 8 4 10.0 5.5  
7000 24.2 75.6 255 7 4 9.7 5.3 | 23.9 75.0 295 8 4 10.2 5.6  
6750 24.9 76.8 255 7 4 9.6 5.3 | 24.7 76.5 295 8 4 10.6 5.8  
6500 25.7 78.3 255 7 3 11.4 6.2 | 25.5 77.9 295 8 4 10.5 5.8  
6250 26.5 79.7 255 7 3 12.2 6.7 | 26.3 79.3 295 7 4 10.6 5.8  
6000 27.4 81.3 255 7 3 9.5 5.2 | 27.1 80.8 295 7 4 10.4 5.7  
5750 28.1 82.6 255 6 3 12.1 6.7 | 27.8 82.0 295 7 4 10.2 5.6  
5500 29.3 84.7 255 6 3 17.7 9.7 | 28.6 83.5 295 7 4 10.3 5.7  
5250 30.5 86.9 255 6 3 13.3 7.3 | 29.4 84.9 295 7 4 10.2 5.6  
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.  
 
CIN (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  
 
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