045  
UXUS97 KGJT 131318  
SRGGJT  
 
SOARING FORECAST  
NATIONAL WEATHER SERVICE GRAND JUNCTION, COLORADO  
0618 MST WEDNESDAY, DECEMBER 13, 2017  
 
THIS FORECAST IS FOR WEDNESDAY, DECEMBER 13, 2017:  
 
IF THE TRIGGER TEMPERATURE OF 62.7 F/17.1 C IS REACHED...THEN  
THERMAL SOARING INDEX....................... FAIR  
MAXIMUM RATE OF LIFT........................ 242 FT/MIN (1.2 M/S)  
MAXIMUM HEIGHT OF THERMALS.................. 7196 FT MSL (2357 FT AGL)  
 
FORECAST MAXIMUM TEMPERATURE................... 52.0 F/11.6 C  
TIME OF TRIGGER TEMPERATURE.................... NONE  
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................. 6253 FT MSL (1414 FT AGL)  
THERMAL SOARING OUTLOOK FOR THURSDAY 12/14..... GOOD  
 
WAVE SOARING INDEX............................. NOT AVAILABLE  
 
REMARKS...  
 
SUNRISE/SUNSET.................... 07:24:56 / 16:52:13 MST  
TOTAL POSSIBLE SUNSHINE........... 9 HR 27 MIN 16 SEC (567 MIN 16 SEC)  
ALTITUDE OF SUN AT 12:08:37 MST... 27.76 DEGREES  
 
UPPER AIR DATA FROM RAWINSONDE OBSERVATION TAKEN ON 12/13/2017 AT 0500 MST  
 
FREEZING LEVEL.................. 5183 FT MSL (344 FT AGL)  
ADDITIONAL FREEZING LEVEL....... 11423 FT MSL (6584 FT AGL)  
CONVECTIVE CONDENSATION LEVEL... 21932 FT MSL (17093 FT AGL)  
LIFTED CONDENSATION LEVEL....... 14656 FT MSL (9816 FT AGL)  
LIFTED INDEX.................... +14.4  
K INDEX......................... -34.0  
 
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 -62.3 -80.1 335 21 11 -0.1 -0.0 97.8 208.0 49.3 M M  
45000 -63.3 -81.9 315 35 18 -0.0 -0.0 70.3 158.5 36.2 M M  
40000 -63.8 -82.8 025 26 14 8.1 4.4 46.5 115.6 23.2 M M  
38000 -62.1 -79.8 005 39 20 4.0 2.2 40.2 104.4 19.6 M M  
36000 -56.8 -70.2 010 33 17 8.9 4.9 39.5 103.0 19.6 M M  
34000 -51.5 -60.7 010 28 14 8.4 4.6 38.6 101.5 19.6 M M  
32000 -45.5 -49.9 015 25 13 9.3 5.1 37.8 100.0 19.5 M M  
30000 -40.2 -40.4 015 15 8 9.4 5.2 37.1 98.8 19.5 M M  
29000 -37.5 -35.5 360 17 9 9.3 5.1 36.9 98.5 19.6 M M  
28000 -34.9 -30.8 350 20 10 7.9 4.3 36.4 97.6 19.5 M M  
27000 -32.8 -27.0 345 23 12 7.1 3.9 35.4 95.8 18.9 M M  
26000 -30.4 -22.7 340 26 14 8.5 4.7 34.7 94.5 18.6 M M  
25000 -28.1 -18.6 335 30 15 8.4 4.6 34.0 93.2 18.2 M M  
24000 -25.5 -13.9 330 34 18 7.8 4.3 33.6 92.4 18.1 M M  
23000 -23.5 -10.3 335 34 18 6.4 3.5 32.4 90.3 17.4 M M  
22000 -21.6 -6.9 335 35 18 6.7 3.7 31.2 88.2 16.6 M M  
21000 -18.8 -1.8 335 35 18 9.9 5.4 31.1 88.0 16.6 M M  
20000 -15.9 3.4 340 36 19 9.4 5.2 31.1 88.0 16.9 M M  
19500 -15.3 4.5 340 35 18 -1.0 -0.5 30.1 86.2 16.1 M M  
19000 -14.7 5.5 345 34 17 7.1 3.9 29.1 84.4 15.3 M M  
18500 -13.7 7.3 345 32 16 7.4 4.1 28.6 83.4 15.0 M M  
18000 -12.7 9.1 340 31 16 5.2 2.9 28.0 82.4 14.6 M M  
17500 -11.9 10.6 340 29 15 6.4 3.5 27.2 81.0 14.0 M M  
17000 -10.2 13.6 330 27 14 7.3 4.0 26.6 79.9 13.6 M M  
16500 -9.1 15.6 330 26 13 7.3 4.0 26.2 79.2 13.3 M M  
16000 -8.1 17.4 325 25 13 7.3 4.0 25.8 78.5 13.0 M M  
15500 -7.0 19.4 330 25 13 7.3 4.0 25.4 77.7 12.7 M M  
15000 -5.9 21.4 335 25 13 7.3 4.0 24.9 76.9 12.4 M M  
14500 -4.8 23.4 340 26 13 7.3 4.0 24.5 76.2 12.1 M M  
14000 -3.7 25.3 345 26 13 7.3 4.0 24.2 75.5 11.8 M M  
13500 -2.6 27.3 350 25 13 6.7 3.7 23.7 74.7 11.5 M M  
13000 -1.9 28.6 350 23 12 3.5 1.9 22.9 73.2 10.8 M M  
12500 -1.4 29.5 340 18 9 3.8 2.1 21.9 71.4 9.9 M M  
12000 -0.8 30.6 320 14 7 3.9 2.2 21.0 69.7 9.0 M M  
11500 -0.1 31.8 310 12 6 7.1 3.9 20.2 68.4 8.3 M M  
11000 1.0 33.8 295 11 6 7.3 4.0 19.8 67.7 8.0 M M  
10500 1.9 35.4 280 9 4 9.0 4.9 19.4 66.9 7.5 M M  
10250 2.6 36.7 270 8 4 8.5 4.7 19.4 66.9 7.5 M M  
10000 3.1 37.6 270 8 4 4.9 2.7 19.1 66.4 7.3 M M  
9750 3.5 38.3 265 9 5 5.5 3.0 18.8 65.8 7.0 M M  
9500 3.9 39.0 265 9 5 5.3 2.9 18.4 65.1 6.6 M M  
9250 4.3 39.7 260 10 5 5.4 3.0 18.1 64.5 6.3 M M  
9000 4.6 40.3 260 10 5 5.0 2.7 17.7 63.9 5.9 M M  
8750 5.0 41.0 260 8 4 4.2 2.3 17.3 63.1 5.6 M M  
8500 5.4 41.7 255 6 3 5.5 3.0 16.9 62.4 5.3 M M  
8250 5.7 42.3 245 4 2 1.2 0.7 16.5 61.7 4.9 M M  
8000 5.6 42.1 215 2 1 -4.0 -2.2 15.5 60.0 4.0 M M  
7750 5.3 41.5 180 4 2 -3.5 -1.9 14.5 58.1 3.0 M M  
7500 5.0 41.0 165 7 3 -4.0 -2.2 13.5 56.3 2.0 M M  
7250 4.5 40.1 165 10 5 -12.7 -7.0 12.2 53.9 0.8 M M  
7000 3.4 38.1 160 12 6 -10.4 -5.7 10.3 50.6 -1.1 257 1.3  
6750 3.2 37.8 160 13 6 2.7 1.5 9.4 48.8 -2.0 255 1.3  
6500 3.5 38.3 160 12 6 3.8 2.1 8.9 48.0 -2.4 239 1.2  
6250 3.8 38.8 155 12 6 5.4 3.0 8.5 47.2 -2.9 223 1.1  
6000 4.1 39.4 155 11 6 -2.0 -1.1 8.0 46.5 -3.3 207 1.1  
5750 3.2 37.8 155 11 6 -20.7 -11.3 6.4 43.5 -4.9 226 1.1  
5500 1.7 35.1 150 12 6 -9.4 -5.1 4.2 39.5 -7.2 263 1.3  
5250 1.5 34.7 150 12 6 -11.0 -6.0 3.2 37.7 -8.2 263 1.3  
5000 -1.0 30.2 150 13 7 -54.6 -30.0 0.0 32.0 -11.3 328 1.7  
 
* * * * * * NUMERICAL WEATHER PREDICTION MODEL FORECAST DATA VALID * * * * * *  
 
12/13/2017 AT 0800 MST | 12/13/2017 AT 1100 MST  
|  
K INDEX... -17.4 LI... +6.8 | K INDEX... -0.9 LI... +8.5  
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 -60.6 -77.1 310 25 13 0.8 0.5 | -61.4 -78.5 320 28 14 1.3 0.7  
45000 -59.5 -75.1 315 32 16 -1.9 -1.0 | -59.6 -75.3 330 35 18 -2.4 -1.3  
40000 -63.5 -82.3 010 35 18 -2.2 -1.2 | -62.7 -80.9 360 36 18 -1.8 -1.0  
38000 -60.3 -76.5 015 31 16 7.7 4.2 | -59.8 -75.6 360 31 16 7.7 4.2  
36000 -55.7 -68.3 010 24 13 7.7 4.2 | -55.2 -67.4 350 25 13 7.7 4.2  
34000 -50.8 -59.4 005 21 11 8.6 4.7 | -50.5 -58.9 340 22 11 7.9 4.3  
32000 -45.6 -50.1 005 22 11 8.6 4.7 | -45.8 -50.4 335 22 12 7.9 4.3  
30000 -40.4 -40.7 360 23 12 8.7 4.8 | -40.2 -40.4 335 25 13 8.9 4.9  
29000 -37.8 -36.0 355 25 13 8.7 4.8 | -37.6 -35.7 330 27 14 8.9 4.9  
28000 -35.2 -31.4 350 26 13 8.7 4.8 | -34.9 -30.8 330 29 15 8.9 4.9  
27000 -32.7 -26.9 345 28 14 8.1 4.4 | -32.4 -26.3 330 30 15 7.9 4.3  
26000 -30.2 -22.4 345 29 15 8.1 4.5 | -30.0 -22.0 335 31 16 7.9 4.4  
25000 -27.8 -18.0 340 31 16 8.2 4.5 | -27.6 -17.7 335 31 16 8.0 4.4  
24000 -25.4 -13.7 340 33 17 7.4 4.1 | -25.3 -13.5 335 31 16 7.3 4.0  
23000 -23.2 -9.8 340 34 17 7.4 4.0 | -23.1 -9.6 340 30 16 7.4 4.1  
22000 -20.5 -4.9 335 35 18 7.4 4.1 | -20.9 -5.6 340 29 15 7.4 4.1  
21000 -18.4 -1.1 335 35 18 6.7 3.7 | -18.8 -1.8 345 28 15 6.8 3.7  
20000 -16.4 2.5 335 34 17 6.7 3.7 | -16.8 1.8 345 28 14 6.9 3.8  
19500 -15.4 4.3 335 33 17 6.7 3.7 | -15.8 3.6 345 28 14 6.9 3.8  
19000 -14.4 6.1 335 32 17 6.7 3.7 | -14.8 5.4 345 28 14 7.1 3.9  
18500 -13.4 7.9 335 31 16 6.7 3.7 | -13.9 7.0 345 27 14 4.6 2.5  
18000 -12.4 9.7 335 30 16 6.8 3.7 | -12.9 8.8 340 27 14 4.3 2.4  
17500 -11.3 11.7 335 29 15 6.2 3.4 | -12.0 10.4 340 27 14 8.6 4.7  
17000 -10.4 13.3 335 28 15 6.3 3.4 | -10.7 12.7 340 26 13 8.3 4.6  
16500 -9.4 15.1 335 28 14 6.1 3.4 | -9.5 14.9 340 25 13 7.5 4.1  
16000 -8.5 16.7 335 26 14 6.0 3.3 | -8.4 16.9 335 24 12 6.9 3.8  
15500 -7.5 18.5 335 25 13 5.9 3.2 | -7.3 18.9 335 23 12 6.7 3.7  
15000 -6.8 19.8 335 24 12 4.8 2.6 | -6.4 20.5 335 22 11 5.9 3.2  
14500 -6.0 21.2 335 22 11 4.9 2.7 | -5.4 22.3 335 21 11 6.2 3.4  
14000 -5.3 22.5 335 20 10 4.6 2.5 | -4.5 23.9 330 19 10 5.0 2.8  
13500 -4.7 23.5 340 17 9 4.6 2.5 | -3.7 25.3 330 17 9 5.3 2.9  
13000 -3.9 25.0 345 15 8 5.4 3.0 | -3.0 26.6 330 15 8 3.8 2.1  
12500 -3.2 26.2 350 13 7 5.6 3.1 | -2.4 27.7 325 13 6 3.7 2.0  
12000 -2.3 27.9 350 11 6 6.4 3.5 | -1.8 28.8 325 10 5 4.7 2.6  
11500 -1.4 29.5 355 10 5 6.6 3.6 | -1.2 29.8 325 7 4 4.9 2.7  
11000 -0.5 31.1 355 9 5 6.7 3.7 | -0.4 31.3 320 5 2 6.0 3.3  
10500 0.5 32.9 360 9 4 7.1 3.9 | 0.4 32.7 330 3 2 6.9 3.8  
10250 1.0 33.8 360 8 4 4.9 2.7 | 0.9 33.6 335 3 1 3.3 1.8  
10000 1.3 34.3 360 8 4 4.0 2.2 | 1.0 33.8 345 2 1 3.6 2.0  
9750 1.7 35.1 360 8 4 5.6 3.1 | 1.5 34.7 005 2 1 7.2 3.9  
9500 2.1 35.8 360 7 4 5.9 3.2 | 1.9 35.4 020 2 1 6.7 3.7  
9250 2.5 36.5 005 7 4 4.7 2.6 | 2.4 36.3 030 3 1 5.2 2.9  
9000 2.8 37.0 005 6 3 3.3 1.8 | 2.7 36.9 040 3 1 3.5 1.9  
8750 3.1 37.6 005 6 3 3.6 2.0 | 3.0 37.4 045 3 1 4.2 2.3  
8500 3.4 38.1 010 5 3 3.3 1.8 | 3.3 37.9 055 3 1 4.1 2.2  
8250 3.6 38.5 015 4 2 1.8 1.0 | 3.6 38.5 060 3 1 2.9 1.6  
8000 3.7 38.7 020 4 2 0.8 0.5 | 3.8 38.8 065 3 1 2.2 1.2  
7750 3.8 38.8 035 3 2 0.9 0.5 | 4.0 39.2 070 2 1 2.2 1.2  
7500 3.8 38.8 050 2 1 0.6 0.3 | 4.1 39.4 080 2 1 1.3 0.7  
7250 3.9 39.0 070 2 1 0.5 0.3 | 4.2 39.6 095 2 1 0.4 0.2  
7000 3.9 39.0 085 2 1 0.6 0.3 | 4.2 39.6 115 1 1 0.9 0.5  
6750 3.9 39.0 105 2 1 0.1 0.1 | 4.2 39.6 135 1 1 -1.2 -0.6  
6500 3.9 39.0 115 2 1 -1.0 -0.6 | 4.1 39.4 150 2 1 0.8 0.5  
6250 3.8 38.8 115 3 2 -2.6 -1.4 | 4.4 39.9 155 2 1 4.7 2.6  
6000 3.6 38.5 110 4 2 1.3 0.7 | 4.7 40.5 160 2 1 2.6 1.4  
5750 3.3 37.9 110 5 2 -19.4 -10.6 | 4.9 40.8 165 2 1 7.3 4.0  
5500 0.2 32.4 100 4 2 -61.2 -33.6 | 5.9 42.6 165 1 1 18.5 10.1  
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  
 
12/13/2017 AT 1400 MST | 12/13/2017 AT 1700 MST  
|  
K INDEX... +2.1 LI... +7.5 | K INDEX... +5.3 LI... +7.2  
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 -61.1 -78.0 330 28 15 1.1 0.6 | -60.7 -77.3 340 27 14 0.6 0.3  
45000 -59.4 -74.9 345 37 19 -0.8 -0.4 | -59.8 -75.6 355 30 16 -0.2 -0.1  
40000 -62.0 -79.6 335 33 17 -1.4 -0.8 | -60.8 -77.4 295 31 16 -0.6 -0.3  
38000 -59.3 -74.7 330 30 15 7.0 3.8 | -58.6 -73.5 290 35 18 5.8 3.2  
36000 -55.1 -67.2 320 27 14 7.0 3.8 | -55.1 -67.2 295 39 20 5.8 3.2  
34000 -50.6 -59.1 315 26 14 8.1 4.4 | -51.2 -60.2 295 41 21 8.0 4.4  
32000 -45.8 -50.4 315 28 14 8.1 4.4 | -46.5 -51.7 295 41 21 8.0 4.4  
30000 -40.8 -41.4 315 30 15 8.7 4.8 | -41.5 -42.7 300 40 21 8.8 4.8  
29000 -38.2 -36.8 320 31 16 8.7 4.8 | -38.9 -38.0 300 38 20 8.7 4.8  
28000 -35.6 -32.1 320 32 16 8.7 4.8 | -36.3 -33.3 305 37 19 8.8 4.8  
27000 -32.5 -26.5 325 33 17 8.0 4.4 | -33.7 -28.7 305 35 18 8.3 4.6  
26000 -30.1 -22.2 330 33 17 8.0 4.4 | -30.7 -23.3 310 32 16 8.2 4.5  
25000 -27.7 -17.9 330 32 17 8.0 4.4 | -28.3 -18.9 310 29 15 8.2 4.5  
24000 -25.4 -13.7 330 32 16 7.3 4.0 | -25.9 -14.6 315 27 14 7.1 3.9  
23000 -23.2 -9.8 330 30 15 7.4 4.0 | -23.8 -10.8 310 27 14 7.1 3.9  
22000 -21.1 -6.0 330 28 14 7.4 4.0 | -21.7 -7.1 310 27 14 7.1 3.9  
21000 -19.0 -2.2 330 26 13 6.4 3.5 | -19.7 -3.5 310 26 14 6.6 3.6  
20000 -17.1 1.2 330 24 12 6.5 3.6 | -17.8 -0.0 305 25 13 6.6 3.6  
19500 -16.1 3.0 330 23 12 6.5 3.6 | -16.8 1.8 305 25 13 6.6 3.6  
19000 -15.2 4.6 330 22 11 6.6 3.6 | -15.8 3.6 300 24 12 6.7 3.7  
18500 -14.3 6.3 330 21 11 5.6 3.1 | -14.9 5.2 300 24 12 6.4 3.5  
18000 -13.5 7.7 325 21 11 5.8 3.2 | -13.9 7.0 300 23 12 6.4 3.5  
17500 -12.7 9.1 320 20 10 6.7 3.6 | -13.0 8.6 300 23 12 6.4 3.5  
17000 -11.5 11.3 320 20 10 7.6 4.2 | -12.0 10.4 300 23 12 6.6 3.6  
16500 -10.4 13.3 320 20 10 7.6 4.2 | -11.1 12.0 300 23 12 6.5 3.6  
16000 -9.3 15.3 320 19 10 6.7 3.7 | -10.1 13.8 300 22 12 7.4 4.1  
15500 -8.3 17.1 320 19 10 6.8 3.7 | -9.0 15.8 300 22 11 7.4 4.0  
15000 -7.2 19.0 320 18 9 7.4 4.1 | -7.9 17.8 300 22 11 7.8 4.3  
14500 -6.0 21.2 320 17 9 7.5 4.1 | -6.6 20.1 300 21 11 7.9 4.3  
14000 -4.9 23.2 315 17 9 6.4 3.5 | -5.4 22.3 295 20 10 7.1 3.9  
13500 -3.5 25.7 310 15 8 6.0 3.3 | -4.4 24.1 295 19 10 6.0 3.3  
13000 -2.7 27.1 305 14 7 4.1 2.2 | -3.0 26.6 290 17 9 4.6 2.5  
12500 -2.0 28.4 300 12 6 4.2 2.3 | -2.3 27.9 285 16 8 4.5 2.5  
12000 -1.3 29.7 290 11 6 5.2 2.9 | -1.6 29.1 280 15 8 4.6 2.5  
11500 -0.5 31.1 285 10 5 5.3 2.9 | -0.9 30.4 275 14 7 4.6 2.5  
11000 0.2 32.4 275 8 4 5.3 2.9 | -0.2 31.6 275 13 7 4.6 2.5  
10500 1.0 33.8 275 7 4 5.9 3.3 | 0.5 32.9 275 12 6 5.1 2.8  
10250 1.3 34.3 270 6 3 3.2 1.8 | 0.8 33.4 270 11 6 2.8 1.6  
10000 1.5 34.7 270 6 3 3.2 1.8 | 0.9 33.6 270 11 5 3.0 1.7  
9750 1.9 35.4 270 5 3 5.8 3.2 | 1.3 34.3 270 10 5 5.4 2.9  
9500 2.2 36.0 270 4 2 5.6 3.1 | 1.6 34.9 265 9 5 4.8 2.7  
9250 2.6 36.7 270 3 2 4.0 2.2 | 1.9 35.4 265 8 4 4.8 2.7  
9000 2.8 37.0 270 3 1 3.2 1.8 | 2.3 36.1 265 7 4 4.8 2.6  
8750 3.1 37.6 275 2 1 4.5 2.5 | 2.6 36.7 260 7 3 5.0 2.7  
8500 3.4 38.1 280 2 1 4.1 2.3 | 3.0 37.4 255 6 3 4.9 2.7  
8250 3.8 38.8 285 1 1 3.9 2.1 | 3.4 38.1 250 5 3 4.9 2.7  
8000 4.0 39.2 295 1 0 3.6 2.0 | 3.7 38.7 245 5 2 4.6 2.5  
7750 4.3 39.7 295 1 0 3.7 2.0 | 4.1 39.4 245 4 2 4.3 2.3  
7500 4.6 40.3 000 0 0 3.0 1.7 | 4.4 39.9 240 4 2 3.9 2.1  
7250 4.8 40.6 290 1 0 2.3 1.3 | 4.7 40.5 240 3 2 3.2 1.8  
7000 4.9 40.8 295 1 1 1.9 1.1 | 4.9 40.8 245 3 2 2.9 1.6  
6750 5.1 41.2 300 2 1 2.4 1.3 | 5.1 41.2 255 3 2 1.7 0.9  
6500 5.4 41.7 305 2 1 7.3 4.0 | 5.2 41.4 265 3 2 3.8 2.1  
6250 6.1 43.0 300 3 1 10.3 5.6 | 5.6 42.1 270 3 2 5.7 3.1  
6000 6.8 44.2 300 3 1 9.1 5.0 | 6.0 42.8 275 4 2 6.4 3.5  
5750 7.5 45.5 300 3 1 9.0 4.9 | 6.5 43.7 275 4 2 4.0 2.2  
5500 8.2 46.8 300 3 1 9.2 5.1 | 6.5 43.7 275 4 2 -1.6 -0.9  
5250 8.9 48.0 300 3 1 9.0 5.0 | 6.4 43.5 275 3 2 -1.4 -0.8  
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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