346  
UXUS97 KGJT 181236  
SRGGJT  
 
SOARING FORECAST  
NATIONAL WEATHER SERVICE GRAND JUNCTION, COLORADO  
0636 MDT FRIDAY, SEPTEMBER 18, 2020  
 
THIS FORECAST IS FOR FRIDAY, SEPTEMBER 18, 2020:  
 
IF THE TRIGGER TEMPERATURE OF 83.3 F/28.5 C IS REACHED...THEN  
THERMAL SOARING INDEX....................... EXCELLENT  
MAXIMUM RATE OF LIFT........................ 1047 FT/MIN (5.3 M/S)  
MAXIMUM HEIGHT OF THERMALS.................. 16594 FT MSL (11755 FT AGL)  
 
FORECAST MAXIMUM TEMPERATURE................... 86.0 F/30.5 C  
TIME OF TRIGGER TEMPERATURE.................... 1245 MDT  
TIME OF OVERDEVELOPMENT........................ 1800 MDT  
MIDDLE/HIGH CLOUDS DURING SOARING WINDOW....... OVERCAST THIN HIGH  
SURFACE WINDS DURING SOARING WINDOW............ 20 MPH OR LESS  
HEIGHT OF THE -3 THERMAL INDEX................. 7708 FT MSL (2869 FT AGL)  
THERMAL SOARING OUTLOOK FOR SATURDAY 09/19..... GOOD  
 
WAVE SOARING INDEX............................. NOT AVAILABLE  
 
REMARKS...  
 
***ATTENTION SOARING FORECAST USERS***THE NATIONAL WEATHER SERVICE IN BOULDER WANTS TO HEAR FROM YOU.  
PLEASE SEND AND EMAIL TO PAUL.T.SCHLATTER@NOAA.GOV AND LET US KNOW HOW YOU USE THE SOARING FORECAST. THANKS!  
 
SUNRISE/SUNSET.................... 06:58:55 / 19:17:09 MDT  
TOTAL POSSIBLE SUNSHINE........... 12 HR 18 MIN 14 SEC (738 MIN 14 SEC)  
ALTITUDE OF SUN AT 13:08:02 MDT... 52.32 DEGREES  
 
UPPER AIR DATA FROM RAWINSONDE OBSERVATION TAKEN ON 09/18/2020 AT 0600 MDT  
 
FREEZING LEVEL.................. 14724 FT MSL (9885 FT AGL)  
CONVECTIVE CONDENSATION LEVEL... 21180 FT MSL (16341 FT AGL)  
LIFTED CONDENSATION LEVEL....... 18664 FT MSL (13824 FT AGL)  
LIFTED INDEX.................... +4.2  
K INDEX......................... +10.0  
 
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 -66.9 -88.4 295 40 21 4.3 2.4 84.0 183.1 31.2 M M  
45000 -61.3 -78.3 280 65 33 6.6 3.6 67.4 153.3 23.3 M M  
40000 -51.3 -60.3 285 57 29 6.4 3.5 60.5 140.9 20.3 M M  
38000 -49.7 -57.5 300 43 22 5.5 3.0 54.2 129.5 16.5 M M  
36000 -46.3 -51.3 310 53 27 8.1 4.4 50.7 123.2 14.5 M M  
34000 -41.6 -42.9 310 52 27 7.8 4.3 49.0 120.3 13.7 M M  
32000 -35.7 -32.3 315 36 18 9.0 4.9 48.1 118.6 13.4 M M  
30000 -30.6 -23.1 310 25 13 7.5 4.1 47.1 116.8 13.0 M M  
29000 -28.3 -18.9 310 21 11 7.7 4.2 46.3 115.3 12.5 M M  
28000 -26.0 -14.8 305 17 9 7.7 4.2 45.6 114.0 12.1 M M  
27000 -23.7 -10.7 300 17 9 7.7 4.2 44.6 112.3 11.5 M M  
26000 -21.4 -6.5 290 17 9 7.5 4.1 43.8 110.9 11.0 M M  
25000 -19.8 -3.6 285 17 9 2.9 1.6 42.2 107.9 9.8 M M  
24000 -18.0 -0.4 280 16 8 6.6 3.6 40.6 105.1 8.6 M M  
23000 -16.0 3.2 275 14 7 6.6 3.6 39.3 102.8 7.7 M M  
22000 -14.1 6.6 270 13 6 6.6 3.6 38.2 100.8 6.8 M M  
21000 -12.1 10.2 265 11 6 6.6 3.6 37.2 98.9 6.0 M M  
20000 -10.1 13.8 255 10 5 6.6 3.6 36.3 97.3 5.3 M M  
19500 -9.1 15.6 245 9 5 7.4 4.1 35.7 96.3 4.9 M M  
19000 -9.0 15.8 235 9 5 -5.5 -3.0 34.2 93.6 3.6 M M  
18500 -9.0 15.8 245 9 5 5.7 3.1 32.6 90.7 2.2 M M  
18000 -8.2 17.2 250 9 5 5.5 3.0 31.8 89.3 1.5 M M  
17500 -7.0 19.4 255 9 5 5.8 3.2 30.7 87.3 0.5 M M  
17000 -5.9 21.4 260 9 5 8.6 4.7 30.4 86.7 0.1 M M  
16500 -4.6 23.7 265 10 5 6.5 3.6 30.2 86.3 -0.1 1127 5.7  
16000 -3.6 25.5 270 10 5 11.3 6.2 29.9 85.8 -0.5 1081 5.5  
15500 -2.1 28.2 265 9 4 9.8 5.4 29.9 85.9 -0.5 1021 5.2  
15000 -0.6 30.9 260 8 4 9.8 5.4 29.9 85.9 -0.5 962 4.9  
14500 0.9 33.6 255 7 3 9.8 5.4 30.0 86.0 -0.4 903 4.6  
14000 2.4 36.3 245 6 3 9.8 5.4 30.0 86.0 -0.4 843 4.3  
13500 3.8 38.8 250 6 3 9.8 5.4 30.0 86.0 -0.4 784 4.0  
13000 5.3 41.5 250 6 3 9.8 5.4 30.0 86.0 -0.4 725 3.7  
12500 6.8 44.2 255 6 3 9.7 5.3 30.0 86.0 -0.4 666 3.4  
12000 8.2 46.8 255 6 3 9.4 5.2 30.0 86.0 -0.4 609 3.1  
11500 9.6 49.3 255 6 3 9.4 5.2 29.9 85.8 -0.5 552 2.8  
11000 11.0 51.8 260 6 3 9.4 5.2 29.8 85.7 -0.6 495 2.5  
10500 12.4 54.3 260 6 3 9.7 5.3 29.8 85.7 -0.6 438 2.2  
10250 13.2 55.8 250 6 3 10.2 5.6 29.8 85.7 -0.6 408 2.1  
10000 13.9 57.0 235 5 3 9.8 5.4 29.9 85.7 -0.6 378 1.9  
9750 14.6 58.3 220 5 3 7.9 4.4 29.8 85.6 -0.6 351 1.8  
9500 15.1 59.2 210 6 3 6.9 3.8 29.6 85.3 -0.9 328 1.7  
9250 15.6 60.1 200 6 3 7.2 4.0 29.4 84.9 -1.1 305 1.5  
9000 16.1 61.0 190 7 4 7.1 3.9 29.2 84.6 -1.3 282 1.4  
8750 16.7 62.1 180 7 4 7.2 3.9 29.0 84.2 -1.5 259 1.3  
8500 17.2 63.0 175 8 4 7.1 3.9 28.8 83.8 -1.7 236 1.2  
8250 17.7 63.9 165 8 4 7.3 4.0 28.6 83.5 -1.9 213 1.1  
8000 18.2 64.8 160 9 5 6.6 3.6 28.4 83.1 -2.1 190 1.0  
7750 18.5 65.3 155 9 5 -1.1 -0.6 27.9 82.3 -2.6 175 0.9  
7500 18.1 64.6 145 9 5 -7.7 -4.2 26.7 80.1 -3.8 181 0.9  
7250 17.6 63.7 140 9 5 -1.2 -0.6 25.6 78.0 -4.9 186 0.9  
7000 17.8 64.0 130 10 5 4.1 2.2 25.0 77.1 -5.5 172 0.9  
6750 18.1 64.6 125 9 5 3.2 1.7 24.5 76.2 -6.0 158 0.8  
6500 18.3 64.9 125 9 4 3.4 1.9 24.1 75.3 -6.5 143 0.7  
6250 18.6 65.5 120 8 4 3.4 1.8 23.6 74.4 -7.0 128 0.6  
6000 18.8 65.8 110 7 4 3.3 1.8 23.1 73.6 -7.5 113 0.6  
5750 19.1 66.4 115 8 4 3.6 2.0 22.6 72.7 -8.0 98 0.5  
5500 19.3 66.7 125 10 5 2.5 1.4 22.1 71.8 -8.5 83 0.4  
5250 19.6 67.3 125 12 6 6.5 3.6 21.6 70.9 -9.0 68 0.3  
5000 19.8 67.6 130 14 7 -9.7 -5.3 21.1 70.0 -9.5 54 0.3  
 
* * * * * * NUMERICAL WEATHER PREDICTION MODEL FORECAST DATA VALID * * * * * *  
 
09/18/2020 AT 0900 MDT | 09/18/2020 AT 1200 MDT  
|  
CAPE... 0.0 LI... +1.8 | CAPE... 0.0 LI... +1.2  
CINH... 0.0 K INDEX... +9.8 | CINH... -0.4 K INDEX... +11.0  
|  
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 -65.7 -86.3 275 24 12 1.5 0.8 | -65.0 -85.0 270 23 12 1.5 0.8  
45000 -61.4 -78.5 275 31 16 6.4 3.5 | -60.7 -77.3 270 32 17 5.4 3.0  
40000 -51.7 -61.1 285 29 15 4.5 2.5 | -52.6 -62.7 280 30 16 5.1 2.8  
38000 -49.0 -56.2 290 25 13 4.4 2.4 | -49.5 -57.1 280 24 12 5.1 2.8  
36000 -46.3 -51.3 295 21 11 3.9 2.2 | -46.4 -51.5 280 17 9 4.7 2.6  
34000 -41.7 -43.1 300 18 9 8.1 4.5 | -41.6 -42.9 275 15 8 8.5 4.7  
32000 -36.9 -34.4 300 14 7 8.0 4.4 | -36.4 -33.5 265 14 7 8.4 4.6  
30000 -31.6 -24.9 295 12 6 8.9 4.9 | -31.5 -24.7 265 12 6 8.2 4.5  
29000 -28.9 -20.0 295 12 6 8.9 4.9 | -29.0 -20.2 260 11 6 8.2 4.5  
28000 -26.2 -15.2 295 11 6 8.1 4.4 | -26.5 -15.7 260 10 5 7.8 4.3  
27000 -24.1 -11.4 295 11 5 7.1 3.9 | -23.8 -10.8 265 9 4 7.3 4.0  
26000 -21.4 -6.5 300 10 5 7.1 3.9 | -21.6 -6.9 270 8 4 7.3 4.0  
25000 -19.2 -2.6 300 9 5 6.3 3.5 | -19.4 -2.9 280 7 3 6.5 3.6  
24000 -17.6 0.3 300 9 4 5.4 3.0 | -17.7 0.1 285 6 3 5.6 3.1  
23000 -16.0 3.2 295 8 4 5.4 3.0 | -16.0 3.2 285 6 3 5.6 3.1  
22000 -14.4 6.1 290 8 4 4.7 2.6 | -14.3 6.3 290 6 3 4.6 2.5  
21000 -13.2 8.2 295 6 3 4.3 2.3 | -13.1 8.4 290 5 2 4.1 2.3  
20000 -11.9 10.6 305 5 3 4.4 2.4 | -12.0 10.4 295 4 2 4.3 2.3  
19500 -11.3 11.7 310 5 3 5.0 2.7 | -11.4 11.5 295 4 2 4.9 2.7  
19000 -10.3 13.5 310 5 2 7.6 4.2 | -10.4 13.3 290 3 2 7.6 4.2  
18500 -9.2 15.4 315 4 2 7.4 4.1 | -9.3 15.3 285 3 2 7.5 4.1  
18000 -8.1 17.4 315 4 2 8.3 4.6 | -8.1 17.4 280 3 2 8.5 4.6  
17500 -6.8 19.8 315 3 2 8.5 4.7 | -6.9 19.6 280 3 1 8.7 4.7  
17000 -5.6 21.9 315 3 1 8.6 4.7 | -5.6 21.9 275 3 1 8.7 4.8  
16500 -4.3 24.3 315 2 1 8.8 4.8 | -4.2 24.4 270 3 1 8.9 4.9  
16000 -3.0 26.6 310 2 1 8.8 4.8 | -2.9 26.8 265 3 1 8.9 4.9  
15500 -1.7 28.9 295 1 1 9.0 4.9 | -1.6 29.1 260 3 1 9.1 5.0  
15000 -0.3 31.5 280 1 1 9.0 4.9 | -0.2 31.6 250 3 1 9.1 5.0  
14500 1.0 33.8 260 1 1 9.0 4.9 | 1.1 34.0 245 3 1 8.9 4.9  
14000 2.3 36.1 245 2 1 9.0 4.9 | 2.4 36.3 240 3 1 8.9 4.9  
13500 3.7 38.7 235 2 1 9.0 4.9 | 3.8 38.8 235 3 2 9.0 4.9  
13000 5.0 41.0 230 2 1 8.9 4.9 | 5.1 41.2 230 3 2 9.1 5.0  
12500 6.3 43.3 230 3 1 8.9 4.9 | 6.5 43.7 230 4 2 9.0 5.0  
12000 7.6 45.7 225 3 1 8.9 4.9 | 7.8 46.0 225 4 2 9.0 4.9  
11500 9.0 48.2 225 3 2 8.9 4.9 | 9.1 48.4 220 4 2 9.0 4.9  
11000 10.3 50.5 215 3 2 8.6 4.7 | 10.5 50.9 220 4 2 8.8 4.8  
10500 11.6 52.9 210 3 2 6.8 3.7 | 11.8 53.2 215 4 2 7.2 3.9  
10250 12.0 53.6 205 3 2 6.1 3.4 | 12.2 54.0 215 4 2 7.5 4.1  
10000 12.6 54.7 200 3 2 8.8 4.8 | 12.9 55.2 215 4 2 10.0 5.5  
9750 13.2 55.8 195 4 2 9.1 5.0 | 13.7 56.7 210 4 2 9.7 5.3  
9500 13.9 57.0 190 4 2 8.3 4.5 | 14.4 57.9 210 4 2 9.1 5.0  
9250 14.4 57.9 185 4 2 7.2 3.9 | 15.0 59.0 210 4 2 8.1 4.4  
9000 15.0 59.0 180 4 2 7.1 3.9 | 15.6 60.1 210 4 2 8.3 4.6  
8750 15.5 59.9 175 5 2 7.4 4.0 | 16.3 61.3 205 4 2 8.6 4.7  
8500 16.5 61.7 170 5 3 5.6 3.1 | 17.4 63.3 200 4 2 7.4 4.1  
8250 16.9 62.4 165 6 3 5.3 2.9 | 18.0 64.4 195 4 2 7.6 4.2  
8000 17.2 63.0 165 6 3 4.4 2.4 | 18.6 65.5 190 3 2 7.6 4.2  
7750 17.5 63.5 160 5 3 3.4 1.9 | 19.1 66.4 185 3 2 7.8 4.3  
7500 17.8 64.0 155 6 3 3.0 1.7 | 19.7 67.5 185 3 2 7.7 4.2  
7250 18.0 64.4 155 6 3 2.9 1.6 | 20.3 68.5 180 3 1 8.1 4.5  
7000 18.2 64.8 150 5 3 1.4 0.8 | 20.9 69.6 175 3 1 9.9 5.5  
6750 18.2 64.8 145 4 2 1.0 0.5 | 21.7 71.1 175 2 1 10.4 5.7  
6500 18.3 64.9 140 4 2 1.6 0.9 | 22.5 72.5 175 2 1 10.6 5.8  
6250 18.4 65.1 135 4 2 1.1 0.6 | 23.3 73.9 170 2 1 8.8 4.8  
6000 18.5 65.3 130 4 2 2.8 1.6 | 24.0 75.2 175 2 1 13.6 7.5  
5750 18.9 66.0 120 3 1 6.8 3.8 | 25.5 77.9 175 2 1 27.3 15.0  
5500 19.2 66.6 100 2 1 -0.5 -0.3 | 27.0 80.6 170 2 1 1.4 0.8  
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  
 
09/18/2020 AT 1500 MDT | 09/18/2020 AT 1800 MDT  
|  
CAPE... +0.2 LI... +0.6 | CAPE... 0.0 LI... +1.2  
CINH... -0.1 K INDEX... +13.8 | CINH... -0.1 K INDEX... +14.4  
|  
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 -64.9 -84.8 265 23 12 1.9 1.0 | -64.5 -84.1 265 23 12 1.7 1.0  
45000 -60.9 -77.6 265 33 17 4.9 2.7 | -60.8 -77.4 265 32 17 4.4 2.4  
40000 -53.0 -63.4 270 32 16 5.8 3.2 | -53.7 -64.7 260 32 16 5.8 3.2  
38000 -49.5 -57.1 265 25 13 5.8 3.2 | -50.2 -58.4 260 25 13 5.8 3.2  
36000 -46.0 -50.8 260 18 9 5.5 3.0 | -46.7 -52.1 250 19 10 5.5 3.0  
34000 -41.3 -42.3 260 16 8 8.2 4.5 | -41.7 -43.1 250 16 8 8.6 4.7  
32000 -36.3 -33.3 260 15 8 8.1 4.4 | -36.5 -33.7 255 15 8 8.5 4.7  
30000 -31.5 -24.7 255 13 7 8.0 4.4 | -31.7 -25.1 255 13 7 8.0 4.4  
29000 -29.1 -20.4 255 13 7 8.0 4.4 | -29.3 -20.7 255 13 6 8.0 4.4  
28000 -26.8 -16.2 255 12 6 7.7 4.2 | -26.9 -16.4 255 12 6 7.5 4.1  
27000 -24.5 -12.1 255 10 5 7.4 4.0 | -24.9 -12.8 255 10 5 6.6 3.6  
26000 -22.3 -8.1 255 9 4 7.4 4.0 | -23.0 -9.4 250 9 5 6.6 3.6  
25000 -19.5 -3.1 250 6 3 6.6 3.6 | -20.5 -4.9 245 7 4 6.3 3.5  
24000 -17.8 -0.0 255 6 3 5.6 3.1 | -18.7 -1.7 240 6 3 6.0 3.3  
23000 -16.2 2.8 255 5 2 5.6 3.1 | -16.9 1.6 235 5 3 6.0 3.3  
22000 -14.5 5.9 260 4 2 4.9 2.7 | -15.1 4.8 230 4 2 5.9 3.3  
21000 -13.2 8.2 250 4 2 4.6 2.5 | -13.4 7.9 230 5 2 6.0 3.3  
20000 -11.9 10.6 245 4 2 4.7 2.6 | -11.7 10.9 225 5 3 6.1 3.3  
19500 -11.2 11.8 245 4 2 5.3 2.9 | -10.8 12.6 225 5 3 6.3 3.4  
19000 -10.2 13.6 240 4 2 8.1 4.4 | -9.8 14.4 225 6 3 7.6 4.2  
18500 -9.0 15.8 240 4 2 7.9 4.3 | -8.7 16.3 225 6 3 7.5 4.1  
18000 -7.8 18.0 240 4 2 8.6 4.7 | -7.5 18.5 225 6 3 8.2 4.5  
17500 -6.6 20.1 235 5 2 8.7 4.8 | -6.3 20.7 225 6 3 8.4 4.6  
17000 -5.3 22.5 235 5 2 8.9 4.9 | -5.0 23.0 225 6 3 8.6 4.7  
16500 -3.9 25.0 235 5 2 9.3 5.1 | -3.7 25.3 230 6 3 9.3 5.1  
16000 -2.5 27.5 235 5 3 9.3 5.1 | -2.3 27.9 230 5 3 9.3 5.1  
15500 -1.1 30.0 235 5 3 9.3 5.1 | -0.9 30.4 230 5 3 9.5 5.2  
15000 0.3 32.5 235 5 3 9.3 5.1 | 0.6 33.1 230 5 3 9.5 5.2  
14500 1.7 35.1 235 5 3 9.4 5.2 | 2.0 35.6 230 5 3 9.5 5.2  
14000 3.1 37.6 235 5 2 9.5 5.2 | 3.4 38.1 235 5 2 9.5 5.2  
13500 4.5 40.1 235 5 2 9.4 5.1 | 4.8 40.6 235 5 2 9.4 5.2  
13000 5.9 42.6 235 5 2 9.3 5.1 | 6.2 43.2 240 4 2 9.4 5.2  
12500 7.3 45.1 235 4 2 9.3 5.1 | 7.6 45.7 240 4 2 9.4 5.1  
12000 8.7 47.7 235 4 2 9.4 5.2 | 9.0 48.2 245 4 2 9.4 5.1  
11500 10.1 50.2 235 4 2 9.4 5.1 | 10.5 50.9 250 4 2 9.3 5.1  
11000 11.5 52.7 240 4 2 9.1 5.0 | 11.8 53.2 255 4 2 8.9 4.9  
10500 12.8 55.0 240 4 2 7.0 3.9 | 13.2 55.8 260 4 2 6.8 3.7  
10250 13.3 55.9 245 3 2 7.5 4.1 | 13.6 56.5 265 4 2 7.5 4.1  
10000 14.0 57.2 245 3 2 10.6 5.8 | 14.4 57.9 265 4 2 11.0 6.0  
9750 14.8 58.6 245 3 2 9.9 5.4 | 15.2 59.4 265 3 2 10.2 5.6  
9500 15.5 59.9 250 3 2 9.7 5.3 | 16.0 60.8 270 3 2 10.1 5.6  
9250 16.2 61.2 255 3 1 9.0 4.9 | 16.7 62.1 275 3 2 9.4 5.1  
9000 16.9 62.4 260 3 1 9.0 4.9 | 17.4 63.3 280 3 2 9.3 5.1  
8750 17.6 63.7 260 3 1 9.3 5.1 | 18.8 65.8 275 3 2 9.1 5.0  
8500 18.2 64.8 260 3 1 8.8 4.8 | 19.4 66.9 280 3 2 7.7 4.2  
8250 18.9 66.0 265 3 1 7.6 4.2 | 20.0 68.0 290 3 2 8.7 4.8  
8000 19.4 66.9 275 2 1 9.4 5.1 | 20.7 69.3 290 3 1 10.7 5.9  
7750 21.1 70.0 270 3 1 9.8 5.4 | 21.5 70.7 285 3 1 9.3 5.1  
7500 21.7 71.1 275 3 1 7.8 4.3 | 22.1 71.8 290 3 1 8.0 4.4  
7250 22.4 72.3 280 2 1 9.3 5.1 | 22.7 72.9 295 3 1 8.4 4.6  
7000 23.1 73.6 280 2 1 11.9 6.5 | 23.4 74.1 295 2 1 9.4 5.1  
6750 24.1 75.4 275 3 1 11.0 6.1 | 24.1 75.4 285 2 1 9.7 5.3  
6500 24.8 76.6 280 2 1 10.0 5.5 | 24.8 76.6 295 2 1 9.7 5.3  
6250 25.5 77.9 285 2 1 8.8 4.8 | 25.6 78.1 300 2 1 9.4 5.2  
6000 26.3 79.3 285 2 1 13.2 7.3 | 26.2 79.2 300 2 1 9.4 5.1  
5750 27.7 81.9 285 2 1 26.8 14.7 | 27.0 80.6 295 2 1 11.1 6.1  
5500 29.4 84.9 295 2 1 9.3 5.1 | 27.8 82.0 305 2 1 13.6 7.5  
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.  
 
042613  
 
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