320  
UXUS97 KGJT 221232  
SRGGJT  
 
SOARING FORECAST  
NATIONAL WEATHER SERVICE GRAND JUNCTION, COLORADO  
0632 MDT TUESDAY, AUGUST 22, 2017  
 
THIS FORECAST IS FOR TUESDAY, AUGUST 22, 2017:  
 
IF THE TRIGGER TEMPERATURE OF 82.3 F/27.9 C IS REACHED...THEN  
THERMAL SOARING INDEX....................... GOOD  
MAXIMUM RATE OF LIFT........................ 579 FT/MIN (2.9 M/S)  
MAXIMUM HEIGHT OF THERMALS.................. 14039 FT MSL (9200 FT AGL)  
 
FORECAST MAXIMUM TEMPERATURE................... 89.0 F/32.1 C  
TIME OF TRIGGER TEMPERATURE.................... 1100 MDT  
TIME OF OVERDEVELOPMENT........................ NONE  
MIDDLE/HIGH CLOUDS DURING SOARING WINDOW....... BROKEN/OVERCAST THIN MIDDLE  
SURFACE WINDS DURING SOARING WINDOW............ 20 MPH OR LESS  
HEIGHT OF THE -3 THERMAL INDEX................. 9558 FT MSL (4719 FT AGL)  
THERMAL SOARING OUTLOOK FOR WEDNESDAY 08/23.... EXCELLENT  
 
WAVE SOARING INDEX............................. NOT AVAILABLE  
 
REMARKS...  
 
SUNRISE/SUNSET.................... 06:34:01 / 20:00:22 MDT  
TOTAL POSSIBLE SUNSHINE........... 13 HR 26 MIN 20 SEC (806 MIN 20 SEC)  
ALTITUDE OF SUN AT 13:16:49 MDT... 62.39 DEGREES  
 
UPPER AIR DATA FROM RAWINSONDE OBSERVATION TAKEN ON 08/22/2017 AT 0600 MDT  
 
FREEZING LEVEL.................. 15516 FT MSL (10677 FT AGL)  
CONVECTIVE CONDENSATION LEVEL... 16089 FT MSL (11250 FT AGL)  
LIFTED CONDENSATION LEVEL....... 16008 FT MSL (11169 FT AGL)  
LIFTED INDEX.................... -0.5  
K INDEX......................... +21.9  
 
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 -64.9 -84.8 265 22 11 -1.2 -0.7 86.5 187.6 31.7 M M  
45000 -58.9 -74.0 235 38 20 5.3 2.9 70.9 159.7 24.5 M M  
40000 -49.1 -56.4 240 43 22 6.5 3.5 63.4 146.1 21.1 M M  
38000 -46.7 -52.1 240 35 18 3.6 2.0 58.2 136.8 18.2 M M  
36000 -45.9 -50.6 260 19 10 -1.0 -0.6 51.0 123.9 13.6 M M  
34000 -42.5 -44.5 220 15 8 8.8 4.8 47.5 117.6 11.4 M M  
32000 -36.7 -34.1 220 10 5 8.4 4.6 46.6 115.8 11.0 M M  
30000 -32.0 -25.6 215 11 6 8.1 4.4 45.2 113.3 10.2 M M  
29000 -29.5 -21.1 215 8 4 8.1 4.4 44.5 112.1 9.8 M M  
28000 -27.2 -17.0 215 6 3 8.0 4.4 43.7 110.7 9.3 M M  
27000 -24.8 -12.6 215 4 2 7.9 4.4 43.1 109.6 8.9 M M  
26000 -22.3 -8.1 220 1 1 9.7 5.3 42.5 108.6 8.6 M M  
25000 -19.4 -2.9 030 1 1 7.0 3.9 42.5 108.5 8.6 M M  
24000 -17.5 0.5 320 1 1 7.0 3.9 41.3 106.4 7.7 M M  
23000 -15.2 4.6 330 1 1 7.9 4.3 40.5 104.9 7.2 M M  
22000 -13.9 7.0 340 1 1 5.0 2.8 38.7 101.6 5.6 M M  
21000 -12.4 9.7 345 2 1 5.7 3.1 37.1 98.8 4.3 M M  
20000 -11.4 11.5 350 2 1 3.0 1.7 35.0 94.9 2.4 M M  
19500 -10.5 13.1 035 2 1 6.1 3.3 34.3 93.8 1.9 M M  
19000 -9.7 14.5 060 3 2 5.8 3.2 33.6 92.5 1.2 M M  
18500 -8.5 16.7 070 4 2 9.4 5.1 33.4 92.0 1.0 M M  
18000 -7.1 19.2 080 5 3 9.0 5.0 33.2 91.7 0.8 M M  
17500 -5.1 22.8 090 7 4 9.0 4.9 33.0 91.3 0.6 M M  
17000 -3.8 25.2 090 8 4 9.0 4.9 32.8 91.1 0.5 M M  
16500 -2.4 27.7 095 9 5 9.0 4.9 32.7 90.9 0.4 M M  
16000 -1.1 30.0 095 10 5 9.3 5.1 32.7 90.8 0.3 M M  
15500 0.3 32.5 095 8 4 9.4 5.2 32.6 90.7 0.2 M M  
15000 1.7 35.1 090 6 3 9.4 5.2 32.5 90.6 0.2 M M  
14500 3.0 37.4 085 4 2 9.2 5.1 32.5 90.5 0.1 M M  
14000 4.4 39.9 075 2 1 8.8 4.8 32.4 90.3 -0.0 767 3.9  
13500 5.7 42.3 075 1 1 8.8 4.8 32.2 90.0 -0.2 713 3.6  
13000 6.9 44.4 075 1 0 7.2 3.9 32.0 89.6 -0.4 661 3.4  
12500 7.9 46.2 000 0 0 7.9 4.4 31.5 88.8 -0.9 618 3.1  
12000 9.1 48.4 000 0 0 8.2 4.5 31.3 88.3 -1.2 567 2.9  
11500 10.3 50.5 195 5 3 8.2 4.5 31.0 87.8 -1.4 517 2.6  
11000 11.5 52.7 195 10 5 8.2 4.5 30.8 87.4 -1.7 466 2.4  
10500 12.6 54.7 185 11 6 7.3 4.0 30.5 86.9 -2.0 416 2.1  
10250 13.1 55.6 180 12 6 6.4 3.5 30.3 86.5 -2.3 394 2.0  
10000 13.6 56.5 180 12 6 6.7 3.7 30.0 86.0 -2.5 372 1.9  
9750 14.1 57.4 175 13 7 6.6 3.6 29.7 85.5 -2.8 351 1.8  
9500 14.6 58.3 175 14 7 6.7 3.7 29.5 85.1 -3.0 329 1.7  
9250 15.0 59.0 170 14 7 6.3 3.5 29.3 84.7 -3.3 307 1.6  
9000 15.5 59.9 170 15 8 7.8 4.3 29.0 84.3 -3.5 285 1.4  
8750 16.2 61.2 170 16 8 9.7 5.3 29.0 84.2 -3.6 258 1.3  
8500 16.9 62.4 165 16 8 9.5 5.2 29.0 84.1 -3.6 229 1.2  
8250 17.6 63.7 165 17 9 9.8 5.4 29.0 84.1 -3.7 201 1.0  
8000 18.3 64.9 165 18 9 9.0 4.9 29.0 84.1 -3.7 172 0.9  
7750 18.7 65.7 160 18 9 -1.5 -0.8 28.6 83.5 -4.1 154 0.8  
7500 18.3 64.9 155 17 9 -2.0 -1.1 27.5 81.5 -5.2 157 0.8  
7250 18.6 65.5 150 17 9 7.7 4.2 27.1 80.7 -5.6 141 0.7  
7000 19.2 66.6 140 17 9 8.5 4.6 26.9 80.5 -5.8 116 0.6  
6750 19.8 67.6 140 17 9 8.1 4.4 26.8 80.3 -5.9 91 0.5  
6500 20.4 68.7 140 18 9 8.9 4.9 26.7 80.1 -6.0 65 0.3  
6250 21.0 69.8 135 18 9 6.0 3.3 26.6 79.9 -6.2 40 0.2  
6000 21.2 70.2 135 19 10 1.2 0.6 26.1 79.0 -6.7 26 0.1  
5750 21.2 70.2 130 18 9 -0.7 -0.4 25.4 77.7 -7.5 19 0.1  
5500 21.2 70.2 125 17 9 3.2 1.7 24.7 76.4 -8.2 12 0.1  
5250 21.8 71.2 120 16 8 10.3 5.7 24.5 76.1 -8.4 M M  
5000 22.4 72.3 115 15 8 0.3 0.2 24.3 75.8 -8.5 M M  
 
* * * * * * NUMERICAL WEATHER PREDICTION MODEL FORECAST DATA VALID * * * * * *  
 
08/22/2017 AT 0900 MDT | 08/22/2017 AT 1200 MDT  
|  
K INDEX... +27.7 LI... -2.0 | K INDEX... +28.1 LI... -3.2  
CAPE... +213.9 CIN... -24.7 | CAPE... +480.8 CIN... -43.3  
|  
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 -63.4 -82.1 250 22 11 2.4 1.3 | -63.7 -82.7 255 25 13 1.9 1.0  
45000 -57.8 -72.0 250 32 17 5.8 3.2 | -58.5 -73.3 250 36 19 6.1 3.4  
40000 -49.5 -57.1 250 40 21 3.8 2.1 | -49.8 -57.6 250 43 22 4.1 2.2  
38000 -47.2 -53.0 255 29 15 3.8 2.1 | -47.3 -53.1 250 34 18 4.1 2.2  
36000 -45.0 -49.0 255 19 10 3.4 1.9 | -44.9 -48.8 250 25 13 3.7 2.0  
34000 -41.3 -42.3 260 13 7 6.6 3.6 | -41.1 -42.0 255 16 8 6.7 3.7  
32000 -36.9 -34.4 265 8 4 7.2 3.9 | -36.6 -33.9 270 5 3 7.3 4.0  
30000 -31.9 -25.4 230 6 3 8.5 4.6 | -31.6 -24.9 245 4 2 8.5 4.7  
29000 -29.4 -20.9 210 6 3 8.5 4.6 | -29.1 -20.4 230 5 2 8.5 4.7  
28000 -26.9 -16.4 195 7 3 7.8 4.3 | -26.7 -16.1 220 5 3 7.5 4.1  
27000 -24.6 -12.3 190 8 4 7.8 4.3 | -24.4 -11.9 205 6 3 7.6 4.2  
26000 -22.3 -8.1 185 9 5 7.8 4.3 | -22.2 -8.0 200 8 4 7.6 4.2  
25000 -19.9 -3.8 185 10 5 7.3 4.0 | -20.0 -4.0 195 9 5 7.3 4.0  
24000 -18.0 -0.4 175 9 5 6.3 3.5 | -17.9 -0.2 185 9 5 6.9 3.8  
23000 -16.2 2.8 160 9 4 6.4 3.5 | -15.9 3.4 180 10 5 6.9 3.8  
22000 -14.3 6.3 145 9 4 6.4 3.5 | -13.9 7.0 170 10 5 6.3 3.5  
21000 -12.5 9.5 130 8 4 6.4 3.5 | -12.2 10.0 160 11 6 5.8 3.2  
20000 -10.6 12.9 110 8 4 6.4 3.5 | -10.5 13.1 150 13 7 5.8 3.2  
19500 -9.7 14.5 105 8 4 6.5 3.5 | -9.6 14.7 145 14 7 5.9 3.2  
19000 -8.7 16.3 100 9 4 7.1 3.9 | -8.6 16.5 140 14 7 8.2 4.5  
18500 -7.1 19.2 095 9 5 7.0 3.9 | -6.8 19.8 135 15 8 8.0 4.4  
18000 -6.0 21.2 095 10 5 8.0 4.4 | -5.6 21.9 130 15 8 7.9 4.3  
17500 -4.9 23.2 095 11 5 7.9 4.3 | -4.4 24.1 125 16 8 7.9 4.3  
17000 -3.8 25.2 095 11 6 7.7 4.2 | -3.2 26.2 125 16 8 7.7 4.2  
16500 -2.7 27.1 095 11 6 7.6 4.2 | -2.2 28.0 120 16 8 7.6 4.2  
16000 -1.6 29.1 095 12 6 7.7 4.2 | -1.1 30.0 120 16 8 7.7 4.2  
15500 -0.4 31.3 095 12 6 7.8 4.3 | -0.1 31.8 120 15 8 7.6 4.2  
15000 0.7 33.3 095 12 6 7.9 4.3 | 1.0 33.8 120 14 7 7.7 4.2  
14500 1.8 35.2 100 11 6 7.6 4.2 | 2.0 35.6 120 13 7 7.4 4.1  
14000 2.8 37.0 105 11 5 7.6 4.2 | 3.1 37.6 120 12 6 7.4 4.1  
13500 3.9 39.0 110 10 5 8.2 4.5 | 4.2 39.6 120 11 6 8.0 4.4  
13000 5.1 41.2 115 8 4 8.3 4.5 | 5.4 41.7 120 9 5 8.1 4.4  
12500 6.3 43.3 120 7 4 8.6 4.7 | 6.5 43.7 120 8 4 7.2 3.9  
12000 7.6 45.7 125 6 3 8.7 4.7 | 7.5 45.5 120 7 3 6.9 3.8  
11500 8.8 47.8 140 5 3 7.8 4.3 | 8.5 47.3 130 5 3 6.7 3.7  
11000 9.9 49.8 155 4 2 7.2 3.9 | 9.4 48.9 145 3 2 6.6 3.6  
10500 10.9 51.6 175 4 2 5.5 3.0 | 10.4 50.7 180 2 1 5.6 3.1  
10250 11.3 52.3 180 4 2 6.0 3.3 | 10.8 51.4 195 2 1 6.7 3.6  
10000 11.9 53.4 185 4 2 8.5 4.6 | 11.4 52.5 220 3 1 8.6 4.7  
9750 12.5 54.5 190 4 2 8.3 4.5 | 12.0 53.6 240 4 2 8.2 4.5  
9500 13.1 55.6 195 4 2 7.4 4.0 | 12.6 54.7 250 4 2 7.6 4.2  
9250 13.6 56.5 195 4 2 6.5 3.6 | 13.1 55.6 255 5 3 7.2 3.9  
9000 14.1 57.4 195 5 2 7.7 4.2 | 13.6 56.5 255 6 3 8.9 4.9  
8750 14.7 58.5 195 5 3 8.2 4.5 | 14.3 57.7 260 7 3 9.8 5.4  
8500 15.3 59.5 195 6 3 7.1 3.9 | 15.0 59.0 260 7 4 9.5 5.2  
8250 15.8 60.4 195 6 3 6.3 3.5 | 15.7 60.3 260 7 4 9.1 5.0  
8000 16.3 61.3 190 7 4 7.6 4.2 | 16.4 61.5 260 7 4 10.3 5.7  
7750 16.8 62.2 190 8 4 7.4 4.1 | 17.2 63.0 260 7 4 11.1 6.1  
7500 17.3 63.1 190 8 4 5.1 2.8 | 18.0 64.4 260 7 4 10.0 5.5  
7250 17.6 63.7 185 9 5 4.1 2.2 | 18.7 65.7 260 7 4 9.7 5.3  
7000 18.0 64.4 180 9 5 5.5 3.0 | 19.4 66.9 260 7 4 10.2 5.6  
6750 18.4 65.1 180 10 5 4.4 2.4 | 20.2 68.4 260 7 4 10.6 5.8  
6500 18.5 65.3 175 9 4 2.4 1.3 | 21.0 69.8 260 7 4 10.7 5.9  
6250 18.7 65.7 170 8 4 2.6 1.4 | 21.8 71.2 260 7 4 10.5 5.8  
6000 18.9 66.0 165 7 3 3.5 1.9 | 22.6 72.7 260 7 4 11.1 6.1  
5750 19.4 66.9 160 6 3 11.1 6.1 | 23.6 74.5 260 7 4 18.8 10.3  
5500 20.6 69.1 160 5 3 20.6 11.3 | 25.4 77.7 265 7 4 29.7 16.3  
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  
 
08/22/2017 AT 1500 MDT | 08/22/2017 AT 1800 MDT  
|  
K INDEX... +25.9 LI... -2.9 | K INDEX... +27.0 LI... -2.6  
CAPE... +649.8 CIN... -74.0 | CAPE... +530.5 CIN... -91.5  
|  
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 -63.8 -82.8 260 23 12 1.7 0.9 | -64.3 -83.7 260 25 13 1.5 0.8  
45000 -58.7 -73.7 255 34 17 6.4 3.5 | -59.5 -75.1 255 37 19 6.1 3.4  
40000 -49.6 -57.3 250 42 22 4.1 2.2 | -50.5 -58.9 255 41 21 5.1 2.8  
38000 -47.1 -52.8 245 34 17 4.1 2.2 | -47.5 -53.5 245 31 16 5.1 2.8  
36000 -44.7 -48.5 235 27 14 3.9 2.1 | -44.4 -47.9 230 23 12 5.1 2.8  
34000 -40.9 -41.6 220 18 9 6.7 3.7 | -40.0 -40.0 205 19 10 7.7 4.2  
32000 -36.4 -33.5 175 13 6 7.4 4.1 | -34.7 -30.5 180 20 10 8.4 4.6  
30000 -31.3 -24.3 170 11 5 8.5 4.7 | -30.0 -22.0 185 16 8 8.0 4.4  
29000 -28.8 -19.8 165 10 5 8.6 4.7 | -27.7 -17.9 190 14 7 8.0 4.4  
28000 -26.3 -15.3 165 9 5 8.1 4.4 | -25.4 -13.7 200 12 6 6.5 3.6  
27000 -23.9 -11.0 170 10 5 8.2 4.5 | -23.4 -10.1 210 12 6 6.6 3.6  
26000 -21.4 -6.5 175 12 6 8.2 4.5 | -21.5 -6.7 225 12 6 6.7 3.7  
25000 -19.0 -2.2 175 13 7 7.4 4.1 | -19.5 -3.1 235 13 7 7.0 3.8  
24000 -17.1 1.2 180 13 7 6.4 3.5 | -17.3 0.9 240 13 6 7.4 4.1  
23000 -15.3 4.5 180 12 6 6.5 3.5 | -15.2 4.6 245 13 6 7.4 4.1  
22000 -13.4 7.9 185 12 6 6.7 3.7 | -13.0 8.6 250 13 6 7.1 3.9  
21000 -11.4 11.5 180 12 6 7.0 3.8 | -11.0 12.2 245 10 5 6.8 3.7  
20000 -9.3 15.3 175 12 6 7.0 3.8 | -9.1 15.6 245 8 4 6.8 3.7  
19500 -8.3 17.1 170 12 6 7.0 3.8 | -8.1 17.4 240 7 4 6.8 3.8  
19000 -6.9 19.6 165 12 6 5.9 3.3 | -7.2 19.0 240 6 3 5.8 3.2  
18500 -6.1 21.0 160 12 6 5.8 3.2 | -5.9 21.4 225 5 2 5.9 3.2  
18000 -5.0 23.0 155 13 7 7.9 4.3 | -5.0 23.0 215 5 2 6.6 3.6  
17500 -3.9 25.0 155 13 7 7.7 4.2 | -4.0 24.8 205 5 3 6.5 3.6  
17000 -2.7 27.1 155 13 7 7.8 4.3 | -3.1 26.4 200 5 3 7.1 3.9  
16500 -1.6 29.1 155 14 7 7.9 4.3 | -2.0 28.4 195 5 3 7.4 4.1  
16000 -0.4 31.3 155 14 7 7.9 4.3 | -0.9 30.4 190 6 3 7.5 4.1  
15500 0.7 33.3 155 14 7 7.8 4.3 | 0.2 32.4 185 6 3 7.6 4.2  
15000 1.8 35.2 155 13 7 7.8 4.3 | 1.3 34.3 185 6 3 7.6 4.2  
14500 3.0 37.4 160 13 7 8.0 4.4 | 2.5 36.5 180 7 3 8.3 4.5  
14000 4.1 39.4 160 13 6 8.0 4.4 | 3.7 38.7 180 7 4 8.3 4.5  
13500 5.3 41.5 160 12 6 7.7 4.2 | 4.9 40.8 175 7 4 8.2 4.5  
13000 6.4 43.5 165 11 6 7.7 4.2 | 6.1 43.0 175 8 4 8.2 4.5  
12500 7.5 45.5 165 10 5 7.9 4.3 | 7.4 45.3 170 8 4 8.3 4.5  
12000 8.7 47.7 165 8 4 8.0 4.4 | 8.6 47.5 170 8 4 8.3 4.6  
11500 9.8 49.6 165 7 3 7.4 4.1 | 9.8 49.6 170 9 4 8.1 4.5  
11000 10.8 51.4 170 6 3 6.8 3.8 | 10.9 51.6 170 9 5 7.7 4.2  
10500 11.7 53.1 170 5 2 6.5 3.6 | 12.1 53.8 170 10 5 3.9 2.2  
10250 12.2 54.0 175 4 2 6.6 3.6 | 12.2 54.0 175 10 5 5.0 2.7  
10000 12.7 54.9 185 4 2 7.1 3.9 | 12.9 55.2 175 11 6 10.8 5.9  
9750 13.2 55.8 205 3 2 7.1 3.9 | 13.6 56.5 175 11 6 10.0 5.5  
9500 13.7 56.7 225 3 2 6.7 3.7 | 14.3 57.7 175 12 6 8.1 4.5  
9250 14.1 57.4 245 4 2 6.4 3.5 | 14.7 58.5 175 12 6 5.9 3.2  
9000 14.6 58.3 260 5 3 6.7 3.7 | 15.2 59.4 170 12 6 7.7 4.2  
8750 15.0 59.0 270 6 3 6.8 3.7 | 15.7 60.3 170 13 7 8.4 4.6  
8500 15.5 59.9 275 8 4 6.4 3.5 | 16.2 61.2 170 13 7 7.2 3.9  
8250 15.9 60.6 275 9 4 6.0 3.3 | 16.7 62.1 170 14 7 6.5 3.5  
8000 16.3 61.3 280 10 5 6.6 3.6 | 17.2 63.0 165 14 7 6.5 3.6  
7750 16.8 62.2 280 10 5 7.6 4.1 | 17.6 63.7 165 15 8 6.1 3.3  
7500 17.4 63.3 280 11 6 8.1 4.5 | 18.0 64.4 165 16 8 5.7 3.1  
7250 17.9 64.2 280 11 6 8.1 4.5 | 18.4 65.1 165 17 9 5.7 3.1  
7000 18.5 65.3 280 12 6 8.7 4.8 | 18.8 65.8 165 18 9 5.2 2.9  
6750 19.2 66.6 280 12 6 10.2 5.6 | 19.2 66.6 160 18 9 6.2 3.4  
6500 20.0 68.0 280 12 6 10.7 5.9 | 19.7 67.5 165 18 9 8.0 4.4  
6250 20.8 69.4 280 12 6 10.3 5.7 | 20.2 68.4 165 18 9 8.1 4.4  
6000 21.5 70.7 280 12 6 11.1 6.1 | 20.8 69.4 165 17 9 8.3 4.6  
5750 22.6 72.7 280 12 6 19.5 10.7 | 21.5 70.7 165 17 9 13.3 7.3  
5500 24.5 76.1 280 12 6 31.3 17.2 | 22.8 73.0 165 16 8 20.6 11.3  
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.  
 
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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