865  
UXUS97 KGJT 171250  
SRGGJT  
 
SOARING FORECAST  
NATIONAL WEATHER SERVICE GRAND JUNCTION, COLORADO  
0650 MDT TUESDAY, OCTOBER 17, 2017  
 
THIS FORECAST IS FOR TUESDAY, OCTOBER 17, 2017:  
 
IF THE TRIGGER TEMPERATURE OF 69.3 F/20.7 C IS REACHED...THEN  
THERMAL SOARING INDEX....................... FAIR  
MAXIMUM RATE OF LIFT........................ 312 FT/MIN (1.6 M/S)  
MAXIMUM HEIGHT OF THERMALS.................. 9320 FT MSL (4481 FT AGL)  
 
FORECAST MAXIMUM TEMPERATURE................... 70.0 F/21.6 C  
TIME OF TRIGGER TEMPERATURE.................... 1430 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................. 7816 FT MSL (2977 FT AGL)  
THERMAL SOARING OUTLOOK FOR WEDNESDAY 10/18.... GOOD  
 
WAVE SOARING INDEX............................. NOT AVAILABLE  
 
REMARKS...  
 
SUNRISE/SUNSET.................... 07:26:12 / 18:33:34 MDT  
TOTAL POSSIBLE SUNSHINE........... 11 HR 7 MIN 22 SEC (667 MIN 22 SEC)  
ALTITUDE OF SUN AT 12:59:27 MDT... 41.37 DEGREES  
 
UPPER AIR DATA FROM RAWINSONDE OBSERVATION TAKEN ON 10/17/2017 AT 0600 MDT  
 
FREEZING LEVEL.................. 14304 FT MSL (9465 FT AGL)  
CONVECTIVE CONDENSATION LEVEL... 25521 FT MSL (20682 FT AGL)  
LIFTED CONDENSATION LEVEL....... 19044 FT MSL (14205 FT AGL)  
LIFTED INDEX.................... +12.2  
K INDEX......................... -37.4  
 
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 -64.8 -84.6 300 52 27 -5.8 -3.2 89.5 193.1 39.3 M M  
45000 -63.4 -82.1 290 54 28 2.8 1.5 67.2 152.9 28.4 M M  
40000 -57.6 -71.7 290 50 26 7.1 3.9 53.2 127.7 21.2 M M  
38000 -54.9 -66.8 290 52 27 -0.3 -0.2 48.5 119.4 18.6 M M  
36000 -50.0 -58.0 290 53 28 8.6 4.7 47.0 116.7 18.1 M M  
34000 -44.6 -48.3 290 53 27 7.3 4.0 45.4 113.7 17.4 M M  
32000 -39.6 -39.3 290 48 25 10.0 5.5 44.3 111.7 17.0 M M  
30000 -35.4 -31.7 295 41 21 6.2 3.4 42.1 107.7 15.8 M M  
29000 -32.9 -27.2 295 40 21 8.9 4.9 41.5 106.7 15.6 M M  
28000 -30.3 -22.5 295 40 20 8.5 4.7 41.1 106.0 15.4 M M  
27000 -27.7 -17.9 300 39 20 8.5 4.7 40.6 105.1 15.2 M M  
26000 -25.2 -13.4 300 39 20 8.2 4.5 40.1 104.2 15.0 M M  
25000 -22.6 -8.7 300 38 20 9.1 5.0 39.7 103.4 14.8 M M  
24000 -20.2 -4.4 295 33 17 7.2 4.0 39.0 102.3 14.5 M M  
23000 -18.0 -0.4 295 31 16 7.3 4.0 38.2 100.7 13.9 M M  
22000 -15.5 4.1 290 29 15 8.9 4.9 37.7 99.9 13.7 M M  
21000 -13.1 8.4 290 27 14 5.7 3.1 37.1 98.8 13.3 M M  
20000 -11.4 11.5 290 26 13 5.9 3.2 35.8 96.4 12.3 M M  
19500 -10.4 13.3 290 26 13 7.5 4.1 35.2 95.3 11.8 M M  
19000 -9.0 15.8 295 25 13 4.9 2.7 34.3 93.8 11.2 M M  
18500 -8.2 17.2 300 25 13 5.0 2.8 33.5 92.3 10.5 M M  
18000 -7.5 18.5 300 24 12 5.1 2.8 32.7 90.8 9.9 M M  
17500 -6.8 19.8 290 23 12 6.2 3.4 31.9 89.4 9.2 M M  
17000 -5.6 21.9 285 23 12 7.8 4.3 31.5 88.7 8.9 M M  
16500 -4.4 24.1 295 22 11 7.6 4.2 31.2 88.1 8.7 M M  
16000 -3.1 26.4 305 21 11 8.1 4.5 30.9 87.6 8.6 M M  
15500 -2.0 28.4 305 20 11 6.0 3.3 30.4 86.7 8.2 M M  
15000 -1.1 30.0 300 20 10 6.1 3.3 29.8 85.6 7.7 M M  
14500 -0.2 31.6 300 19 10 5.1 2.8 29.2 84.5 7.3 M M  
14000 0.4 32.7 300 19 10 3.6 2.0 28.2 82.7 6.4 M M  
13500 0.9 33.6 300 16 8 3.6 2.0 27.2 80.9 5.5 M M  
13000 1.4 34.5 300 13 7 3.7 2.0 26.2 79.1 4.6 M M  
12500 2.0 35.6 290 12 6 5.0 2.8 25.2 77.3 3.6 M M  
12000 3.0 37.4 275 11 6 7.0 3.9 24.7 76.4 3.2 M M  
11500 4.0 39.2 280 11 6 7.1 3.9 24.2 75.6 2.8 M M  
11000 5.1 41.2 290 11 6 7.1 3.9 23.8 74.8 2.4 M M  
10500 6.1 43.0 295 11 6 7.6 4.2 23.4 74.1 2.0 M M  
10250 6.7 44.1 295 11 6 5.3 2.9 23.2 73.7 1.8 M M  
10000 6.9 44.4 295 11 6 3.0 1.7 22.7 72.8 1.3 M M  
9750 7.2 45.0 290 9 5 3.8 2.1 22.2 71.9 0.9 M M  
9500 7.4 45.3 275 8 4 3.2 1.7 21.7 71.1 0.4 M M  
9250 7.7 45.9 260 7 3 4.8 2.6 21.2 70.2 -0.1 309 1.6  
9000 8.2 46.8 240 6 3 8.2 4.5 21.0 69.8 -0.3 287 1.5  
8750 8.9 48.0 230 5 3 11.2 6.2 21.0 69.7 -0.4 258 1.3  
8500 9.6 49.3 210 4 2 4.7 2.6 21.0 69.7 -0.4 230 1.2  
8250 9.4 48.9 190 4 2 -7.6 -4.2 20.0 68.0 -1.3 227 1.2  
8000 8.9 48.0 170 5 3 -2.5 -1.4 18.7 65.7 -2.5 235 1.2  
7750 9.1 48.4 160 5 3 6.1 3.4 18.2 64.8 -3.0 221 1.1  
7500 9.5 49.1 155 6 3 5.4 3.0 17.9 64.2 -3.4 202 1.0  
7250 9.9 49.8 155 6 3 6.9 3.8 17.6 63.6 -3.7 182 0.9  
7000 10.3 50.5 150 7 4 1.8 1.0 17.3 63.1 -4.0 162 0.8  
6750 10.1 50.2 145 7 4 -5.9 -3.2 16.3 61.3 -5.0 161 0.8  
6500 9.8 49.6 140 7 4 -0.7 -0.4 15.2 59.4 -6.1 163 0.8  
6250 10.0 50.0 135 7 4 4.3 2.4 14.7 58.5 -6.6 149 0.8  
6000 10.3 50.5 130 7 4 3.1 1.7 14.2 57.6 -7.1 134 0.7  
5750 10.6 51.1 135 7 4 4.6 2.5 13.8 56.8 -7.6 119 0.6  
5500 10.8 51.4 140 8 4 -0.1 -0.1 13.3 55.9 -8.0 103 0.5  
5250 10.0 50.0 145 9 4 -25.3 -13.9 11.8 53.2 -9.6 120 0.6  
5000 7.0 44.6 140 7 4 -50.6 -27.7 8.0 46.5 -13.3 203 1.0  
 
* * * * * * NUMERICAL WEATHER PREDICTION MODEL FORECAST DATA VALID * * * * * *  
 
10/17/2017 AT 0900 MDT | 10/17/2017 AT 1200 MDT  
|  
K INDEX... -9.4 LI... +8.4 | K INDEX... -10.7 LI... +7.6  
CAPE... 0.0 CIN... 0.0 | CAPE... 0.0 CIN... 0.0  
|  
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 -65.2 -85.4 295 47 24 2.3 1.2 | -65.1 -85.2 290 47 24 2.4 1.3  
45000 -61.7 -79.1 295 53 27 2.4 1.3 | -61.7 -79.1 290 50 26 1.8 1.0  
40000 -58.0 -72.4 290 48 25 5.5 3.0 | -58.8 -73.8 285 45 23 6.0 3.3  
38000 -53.9 -65.0 290 47 24 6.8 3.7 | -54.2 -65.6 285 44 23 7.7 4.2  
36000 -49.4 -56.9 290 46 24 6.8 3.7 | -49.0 -56.2 290 44 23 7.7 4.2  
34000 -44.8 -48.6 290 42 22 7.9 4.3 | -44.5 -48.1 285 42 22 7.5 4.1  
32000 -40.0 -40.0 290 38 20 7.9 4.3 | -40.0 -40.0 280 40 21 7.5 4.1  
30000 -35.4 -31.7 290 35 18 7.7 4.2 | -35.4 -31.7 280 38 19 7.7 4.2  
29000 -33.1 -27.6 290 34 18 7.7 4.2 | -33.1 -27.6 285 36 19 7.7 4.2  
28000 -30.7 -23.3 290 33 17 7.9 4.3 | -30.8 -23.4 285 35 18 7.9 4.3  
27000 -28.2 -18.8 295 32 17 8.4 4.6 | -28.3 -18.9 285 34 17 8.5 4.7  
26000 -25.7 -14.3 295 32 16 8.4 4.6 | -25.8 -14.4 285 32 16 8.5 4.7  
25000 -23.2 -9.8 295 31 16 8.5 4.6 | -23.2 -9.8 285 31 16 8.6 4.7  
24000 -20.8 -5.4 300 30 16 7.9 4.3 | -20.8 -5.4 290 29 15 7.8 4.3  
23000 -18.4 -1.1 300 29 15 7.9 4.3 | -18.5 -1.3 290 28 14 7.8 4.3  
22000 -16.1 3.0 300 29 15 8.0 4.4 | -16.1 3.0 295 27 14 7.8 4.3  
21000 -13.9 7.0 305 28 14 7.2 3.9 | -14.0 6.8 295 25 13 7.1 3.9  
20000 -11.2 11.8 315 26 14 7.2 3.9 | -11.3 11.7 305 23 12 7.1 3.9  
19500 -10.1 13.8 315 26 13 7.0 3.9 | -10.3 13.5 305 22 11 7.1 3.9  
19000 -9.2 15.4 320 25 13 5.7 3.1 | -9.2 15.4 310 21 11 6.8 3.7  
18500 -8.3 17.1 320 24 12 5.8 3.2 | -8.2 17.2 315 19 10 6.8 3.7  
18000 -7.5 18.5 320 23 12 5.9 3.2 | -7.2 19.0 320 18 9 6.7 3.7  
17500 -6.6 20.1 320 22 12 6.0 3.3 | -6.2 20.8 325 17 9 6.7 3.7  
17000 -5.8 21.6 315 22 11 6.2 3.4 | -5.2 22.6 325 16 8 6.8 3.7  
16500 -4.7 23.5 315 21 11 7.1 3.9 | -4.2 24.4 325 15 8 7.1 3.9  
16000 -3.7 25.3 315 20 11 7.1 3.9 | -3.1 26.4 325 15 8 7.2 3.9  
15500 -2.6 27.3 310 20 10 7.0 3.8 | -2.1 28.2 325 14 7 6.7 3.7  
15000 -1.6 29.1 310 19 10 7.0 3.8 | -1.1 30.0 320 14 7 6.7 3.7  
14500 -0.5 31.1 310 18 9 5.9 3.2 | -0.1 31.8 320 14 7 6.4 3.5  
14000 0.3 32.5 310 17 9 5.5 3.0 | 0.8 33.4 315 13 7 6.2 3.4  
13500 1.2 34.2 305 16 8 5.4 2.9 | 1.8 35.2 310 13 7 5.7 3.1  
13000 1.9 35.4 300 15 8 5.2 2.9 | 2.6 36.7 305 12 6 5.0 2.7  
12500 2.7 36.9 300 13 7 5.5 3.0 | 3.3 37.9 300 12 6 5.1 2.8  
12000 3.6 38.5 295 12 6 6.0 3.3 | 4.1 39.4 295 10 5 5.5 3.0  
11500 4.5 40.1 290 11 6 6.1 3.3 | 5.0 41.0 290 9 5 5.6 3.1  
11000 5.4 41.7 285 10 5 6.1 3.4 | 5.8 42.4 285 8 4 5.8 3.2  
10500 6.3 43.3 280 9 5 5.4 2.9 | 6.7 44.1 275 8 4 5.2 2.8  
10250 6.6 43.9 280 9 5 3.6 2.0 | 7.0 44.6 275 8 4 4.0 2.2  
10000 6.9 44.4 275 9 5 5.3 2.9 | 7.3 45.1 270 7 4 5.5 3.0  
9750 7.4 45.3 275 9 5 7.0 3.8 | 7.8 46.0 265 7 4 6.7 3.7  
9500 7.9 46.2 270 9 5 5.6 3.1 | 8.3 46.9 265 7 4 5.9 3.2  
9250 8.2 46.8 270 9 4 4.3 2.4 | 8.7 47.7 260 7 4 5.1 2.8  
9000 8.5 47.3 265 8 4 4.8 2.6 | 9.0 48.2 260 7 4 5.4 2.9  
8750 8.9 48.0 260 7 4 5.6 3.1 | 9.5 49.1 250 6 3 5.9 3.3  
8500 9.3 48.7 255 6 3 4.0 2.2 | 9.9 49.8 245 5 3 4.7 2.6  
8250 9.6 49.3 240 5 3 2.6 1.4 | 10.2 50.4 230 5 2 3.7 2.0  
8000 9.8 49.6 225 4 2 3.1 1.7 | 10.5 50.9 215 4 2 4.0 2.2  
7750 10.0 50.0 205 4 2 2.8 1.6 | 10.8 51.4 200 4 2 4.5 2.5  
7500 10.2 50.4 190 4 2 2.4 1.3 | 11.1 52.0 190 4 2 4.9 2.7  
7250 10.3 50.5 180 5 3 1.9 1.0 | 11.5 52.7 190 4 2 5.1 2.8  
7000 10.5 50.9 175 6 3 3.1 1.7 | 11.8 53.2 185 4 2 4.5 2.5  
6750 10.7 51.3 170 7 3 -0.3 -0.2 | 12.2 54.0 180 4 2 6.3 3.5  
6500 10.4 50.7 160 6 3 -4.6 -2.5 | 12.8 55.0 185 4 2 8.4 4.6  
6250 10.2 50.4 150 6 3 -1.6 -0.9 | 13.4 56.1 185 3 2 8.0 4.4  
6000 9.9 49.8 135 6 3 -9.2 -5.0 | 14.0 57.2 185 3 2 8.5 4.7  
5750 8.8 47.8 130 6 3 -17.1 -9.4 | 14.8 58.6 185 3 1 14.9 8.2  
5500 7.7 45.9 115 5 3 -8.6 -4.7 | 16.3 61.3 190 3 1 24.4 13.4  
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  
 
10/17/2017 AT 1500 MDT | 10/17/2017 AT 1800 MDT  
|  
K INDEX... -12.7 LI... +7.0 | K INDEX... -7.1 LI... +6.7  
CAPE... 0.0 CIN... 0.0 | CAPE... 0.0 CIN... 0.0  
|  
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 -65.0 -85.0 285 48 25 2.2 1.2 | -65.4 -85.7 285 46 23 2.2 1.2  
45000 -61.8 -79.2 285 51 26 1.8 1.0 | -62.1 -79.8 285 46 24 1.8 1.0  
40000 -58.8 -73.8 295 53 27 6.4 3.5 | -59.2 -74.6 285 50 26 7.1 3.9  
38000 -54.0 -65.2 290 51 26 8.0 4.4 | -54.1 -65.4 285 50 26 8.5 4.7  
36000 -49.3 -56.7 290 49 25 8.0 4.4 | -49.0 -56.2 285 50 26 8.5 4.7  
34000 -44.3 -47.7 285 45 23 7.0 3.8 | -43.7 -46.7 285 48 25 7.5 4.1  
32000 -40.1 -40.2 280 41 21 7.1 3.9 | -39.3 -38.7 285 45 23 7.5 4.1  
30000 -35.5 -31.9 280 39 20 8.0 4.4 | -34.9 -30.8 285 42 21 7.2 4.0  
29000 -33.1 -27.6 280 38 19 8.0 4.4 | -32.8 -27.0 285 40 20 7.2 4.0  
28000 -30.7 -23.3 285 36 19 8.1 4.4 | -30.6 -23.1 280 38 20 7.4 4.0  
27000 -28.2 -18.8 285 35 18 8.5 4.6 | -28.2 -18.8 280 37 19 8.0 4.4  
26000 -25.7 -14.3 285 34 17 8.5 4.6 | -25.9 -14.6 280 35 18 8.0 4.4  
25000 -23.2 -9.8 285 33 17 8.5 4.7 | -23.5 -10.3 280 34 17 8.0 4.4  
24000 -20.8 -5.4 285 31 16 7.9 4.3 | -21.1 -6.0 280 32 17 8.0 4.4  
23000 -18.4 -1.1 285 29 15 7.9 4.3 | -18.7 -1.7 280 31 16 8.1 4.4  
22000 -16.0 3.2 285 28 14 8.0 4.4 | -16.3 2.7 280 29 15 8.2 4.5  
21000 -13.8 7.2 290 25 13 7.2 3.9 | -14.0 6.8 280 26 13 7.5 4.1  
20000 -11.2 11.8 290 22 11 7.2 3.9 | -11.8 10.8 280 23 12 7.5 4.1  
19500 -10.1 13.8 290 20 11 7.1 3.9 | -10.6 12.9 280 21 11 7.5 4.1  
19000 -9.1 15.6 295 19 10 6.5 3.5 | -9.1 15.6 275 18 9 6.2 3.4  
18500 -8.1 17.4 295 17 9 6.5 3.6 | -8.1 17.4 275 17 9 6.3 3.5  
18000 -7.1 19.2 300 15 8 6.6 3.6 | -7.2 19.0 270 15 8 7.0 3.8  
17500 -6.1 21.0 300 13 7 6.7 3.7 | -6.1 21.0 265 13 7 7.3 4.0  
17000 -5.1 22.8 305 11 5 6.8 3.7 | -5.0 23.0 260 12 6 7.3 4.0  
16500 -4.1 24.6 305 9 5 7.4 4.0 | -4.0 24.8 260 10 5 6.8 3.7  
16000 -3.0 26.6 310 8 4 7.3 4.0 | -2.9 26.8 255 10 5 6.8 3.7  
15500 -1.9 28.6 310 7 4 7.7 4.2 | -1.9 28.6 255 9 5 7.0 3.9  
15000 -0.8 30.6 305 7 4 7.7 4.2 | -0.9 30.4 250 9 4 7.1 3.9  
14500 0.4 32.7 305 7 3 6.9 3.8 | 0.1 32.2 250 8 4 6.9 3.8  
14000 1.3 34.3 300 7 4 6.5 3.6 | 1.2 34.2 250 9 4 6.7 3.7  
13500 2.3 36.1 300 7 4 6.2 3.4 | 2.2 36.0 250 9 5 6.5 3.6  
13000 3.2 37.8 290 7 4 5.7 3.2 | 3.1 37.6 250 10 5 6.3 3.4  
12500 4.1 39.4 285 8 4 5.7 3.1 | 4.1 39.4 250 10 5 6.4 3.5  
12000 4.9 40.8 275 8 4 5.5 3.0 | 5.1 41.2 245 11 6 7.0 3.8  
11500 5.8 42.4 270 8 4 5.7 3.1 | 6.1 43.0 245 12 6 7.0 3.9  
11000 6.7 44.1 265 8 4 6.3 3.5 | 7.2 45.0 245 12 6 7.7 4.2  
10500 7.6 45.7 255 9 4 5.7 3.1 | 8.4 47.1 245 12 6 5.6 3.1  
10250 8.0 46.4 255 9 4 5.3 2.9 | 8.6 47.5 245 12 6 2.9 1.6  
10000 8.5 47.3 255 9 5 6.8 3.7 | 8.9 48.0 245 12 6 7.3 4.0  
9750 9.0 48.2 255 9 5 7.6 4.2 | 9.6 49.3 245 11 6 10.0 5.5  
9500 9.5 49.1 250 9 5 7.0 3.8 | 10.3 50.5 250 10 5 8.1 4.5  
9250 10.0 50.0 250 8 4 6.2 3.4 | 10.8 51.4 250 10 5 4.8 2.6  
9000 10.5 50.9 250 8 4 6.4 3.5 | 11.1 52.0 250 9 5 5.2 2.8  
8750 11.0 51.8 250 7 4 7.3 4.0 | 11.6 52.9 255 8 4 7.2 4.0  
8500 11.5 52.7 250 7 3 5.5 3.0 | 12.1 53.8 255 8 4 5.6 3.1  
8250 11.8 53.2 250 6 3 3.6 2.0 | 12.4 54.3 260 7 4 3.9 2.1  
8000 12.1 53.8 255 5 2 4.2 2.3 | 12.7 54.9 265 6 3 4.2 2.3  
7750 12.4 54.3 255 4 2 4.9 2.7 | 13.1 55.6 270 6 3 5.1 2.8  
7500 12.8 55.0 255 3 2 6.8 3.7 | 13.5 56.3 275 5 2 5.0 2.7  
7250 13.4 56.1 260 3 2 7.8 4.3 | 13.8 56.8 280 4 2 4.7 2.6  
7000 13.9 57.0 265 3 2 7.4 4.1 | 14.2 57.6 290 4 2 4.5 2.4  
6750 14.5 58.1 265 3 2 9.3 5.1 | 14.5 58.1 300 3 2 5.2 2.8  
6500 15.3 59.5 270 3 2 11.0 6.1 | 15.0 59.0 305 3 2 7.9 4.3  
6250 16.1 61.0 270 3 2 11.0 6.0 | 15.7 60.3 300 3 2 8.3 4.6  
6000 16.9 62.4 270 3 2 10.7 5.9 | 16.3 61.3 300 3 2 9.8 5.4  
5750 17.8 64.0 270 3 2 14.8 8.1 | 17.0 62.6 300 4 2 7.5 4.1  
5500 19.2 66.6 270 3 2 22.5 12.4 | 17.2 63.0 300 3 2 -1.8 -1.0  
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.  
 
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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