074  
UXUS97 KBOU 211252  
SRGBOU  
 
SOARING FORECAST  
NATIONAL WEATHER SERVICE DENVER/BOULDER, COLORADO  
0651 MDT SATURDAY, OCTOBER 21, 2017  
 
THIS FORECAST IS FOR SATURDAY, OCTOBER 21, 2017:  
 
IF THE TRIGGER TEMPERATURE OF 49.9 F/10.0 C IS REACHED...THEN  
THERMAL SOARING INDEX....................... FAIR  
MAXIMUM RATE OF LIFT........................ 394 FT/MIN (2.0 M/S)  
MAXIMUM HEIGHT OF THERMALS.................. 11091 FT MSL (5769 FT AGL)  
 
FORECAST MAXIMUM TEMPERATURE................... 56.0 F/13.8 C  
TIME OF TRIGGER TEMPERATURE.................... 1100 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................. 9438 FT MSL (4116 FT AGL)  
THERMAL SOARING OUTLOOK FOR SUNDAY 10/22....... GOOD  
 
WAVE SOARING INDEX............................. POOR  
WAVE SOARING INDEX TREND (TO 1800 MDT)......... BECOMING GOOD BY 1500 MDT  
HEIGHT OF STABLE LAYER (12-18K FT MSL)......... NONE  
WEAK PVA/NVA (THROUGH 1800 MDT)................ WEAK NVA  
POTENTIAL HEIGHT OF WAVE....................... 22044 FT MSL (16722 FT AGL)  
WAVE SOARING OUTLOOK FOR SUNDAY 10/22.......... FAIR  
 
REMARKS...  
 
SUNRISE/SUNSET.................... 07:16:39 / 18:11:21 MDT  
TOTAL POSSIBLE SUNSHINE........... 10 HR 54 MIN 42 SEC (654 MIN 42 SEC)  
ALTITUDE OF SUN AT 12:44:00 MDT... 39.13 DEGREES  
 
UPPER AIR DATA FROM NUMERICAL MODEL FORECAST VALID ON 10/21/2017 AT 0600 MDT  
 
FREEZING LEVEL.................. 7803 FT MSL (2481 FT AGL)  
CONVECTIVE CONDENSATION LEVEL... 16661 FT MSL (11339 FT AGL)  
LIFTED CONDENSATION LEVEL....... 14435 FT MSL (9113 FT AGL)  
LIFTED INDEX.................... +5.7  
K INDEX......................... +13.8  
 
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 -56.1 -69.0 235 16 8 2.2 1.2 M M M M M  
45000 -52.6 -62.7 240 24 12 0.8 0.5 M M M M M  
40000 -52.3 -62.1 230 25 13 0.2 0.1 M M M M M  
38000 -51.7 -61.1 225 25 13 2.1 1.2 M M M M M  
36000 -50.4 -58.7 220 25 13 2.1 1.1 M M M M M  
34000 -49.2 -56.6 210 25 13 2.7 1.5 M M M M M  
32000 -47.0 -52.6 205 22 11 3.2 1.7 M M M M M  
30000 -44.8 -48.6 200 19 10 7.2 3.9 31.1 88.1 13.4 M M  
29000 -42.8 -45.0 200 19 10 6.8 3.7 29.8 85.7 12.5 M M  
28000 -40.8 -41.4 200 18 9 6.8 3.7 28.7 83.6 11.8 M M  
27000 -38.8 -37.8 195 17 9 6.7 3.7 27.6 81.7 11.1 M M  
26000 -36.4 -33.5 200 17 9 8.4 4.6 26.9 80.4 10.7 M M  
25000 -33.9 -29.0 205 17 9 8.4 4.6 26.4 79.4 10.3 M M  
24000 -31.4 -24.5 205 18 9 8.4 4.6 25.9 78.7 10.1 M M  
23000 -28.9 -20.0 210 18 9 8.3 4.6 25.4 77.7 9.8 M M  
22000 -26.4 -15.5 220 17 9 8.3 4.6 24.8 76.7 9.4 M M  
21000 -23.9 -11.0 225 17 9 8.2 4.5 24.4 75.9 9.1 M M  
20000 -21.7 -7.1 230 16 8 7.3 4.0 23.5 74.3 8.5 M M  
19500 -20.6 -5.1 230 15 8 7.3 4.0 23.1 73.5 8.1 M M  
19000 -19.6 -3.3 235 14 7 7.4 4.0 22.7 72.8 7.8 M M  
18500 -18.5 -1.3 235 13 7 7.5 4.1 22.3 72.1 7.5 M M  
18000 -17.5 0.5 240 12 6 6.1 3.3 21.8 71.2 7.1 M M  
17500 -16.6 2.1 240 11 6 6.3 3.4 21.2 70.1 6.6 M M  
17000 -15.2 4.6 245 10 5 6.1 3.3 20.3 68.5 5.8 M M  
16500 -14.4 6.1 245 10 5 6.1 3.4 19.7 67.4 5.2 M M  
16000 -13.5 7.7 245 9 5 6.1 3.4 19.1 66.3 4.7 M M  
15500 -12.6 9.3 240 8 4 6.2 3.4 18.4 65.2 4.2 M M  
15000 -11.7 10.9 240 7 4 6.3 3.5 17.8 64.1 3.6 M M  
14500 -10.7 12.7 245 6 3 6.5 3.6 17.3 63.1 3.1 M M  
14000 -9.8 14.4 250 5 3 6.4 3.5 16.8 62.2 2.7 M M  
13500 -8.8 16.2 260 5 3 6.0 3.3 16.2 61.1 2.1 M M  
13000 -7.9 17.8 270 6 3 6.1 3.4 15.6 60.0 1.6 M M  
12500 -6.9 19.6 280 7 3 7.3 4.0 15.1 59.2 1.2 M M  
12000 -5.8 21.6 285 8 4 7.2 3.9 14.7 58.4 0.9 M M  
11500 -4.8 23.4 290 9 5 5.7 3.1 14.1 57.5 0.4 M M  
11000 -3.8 25.2 295 12 6 5.8 3.2 13.5 56.3 -0.1 385 2.0  
10500 -3.2 26.2 300 13 7 3.4 1.9 12.7 54.8 -0.9 350 1.8  
10250 -2.9 26.8 300 14 7 3.9 2.1 12.2 54.0 -1.4 334 1.7  
10000 -2.6 27.3 305 15 8 3.1 1.7 11.7 53.1 -1.8 319 1.6  
9750 -2.4 27.7 305 16 8 3.0 1.6 11.2 52.1 -2.4 306 1.6  
9500 -2.2 28.0 305 16 8 3.7 2.0 10.7 51.2 -2.9 291 1.5  
9250 -1.9 28.6 310 16 8 3.4 1.9 10.2 50.3 -3.4 276 1.4  
9000 -1.7 28.9 310 16 8 3.7 2.0 9.7 49.5 -3.8 260 1.3  
8750 -1.4 29.5 310 15 8 3.6 2.0 9.2 48.6 -4.3 244 1.2  
8500 -1.1 30.0 310 14 7 3.5 1.9 8.7 47.7 -4.8 230 1.2  
8250 -0.9 30.4 310 14 7 3.1 1.7 8.3 46.9 -5.3 215 1.1  
8000 -0.6 30.9 315 13 7 6.8 3.7 7.8 46.1 -5.7 199 1.0  
7750 0.1 32.2 315 12 6 9.1 5.0 7.8 46.0 -5.8 172 0.9  
7500 0.6 33.1 320 11 6 7.3 4.0 7.6 45.7 -6.0 147 0.7  
7250 1.2 34.2 320 10 5 8.7 4.8 7.5 45.5 -6.2 122 0.6  
7000 2.0 35.6 320 10 5 11.1 6.1 7.5 45.5 -6.2 93 0.5  
6750 2.8 37.0 325 10 5 10.0 5.5 7.6 45.7 -6.1 61 0.3  
6500 3.4 38.1 325 9 5 8.2 4.5 7.5 45.5 -6.2 34 0.2  
6250 4.1 39.4 325 9 5 10.1 5.5 7.5 45.4 -6.3 7 0.0  
6000 4.9 40.8 330 8 4 11.6 6.3 7.5 45.6 -6.2 M M  
5750 5.7 42.3 330 8 4 9.6 5.3 7.6 45.8 -6.1 M M  
5500 6.3 43.3 335 7 4 7.2 4.0 7.5 45.5 -6.3 M M  
 
* * * * * * NUMERICAL WEATHER PREDICTION MODEL FORECAST DATA VALID * * * * * *  
 
10/21/2017 AT 0900 MDT | 10/21/2017 AT 1200 MDT  
|  
CAPE... 0.0 LI... +9.2 | CAPE... 0.0 LI... +6.0  
CINH... 0.0 K INDEX... -11.8 | CINH... 0.0 K INDEX... -10.8  
|  
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 -55.6 -68.1 240 14 7 1.6 0.9 | -55.6 -68.1 235 15 8 1.4 0.8  
45000 -53.0 -63.4 250 21 11 2.1 1.1 | -53.3 -63.9 255 17 9 2.1 1.1  
40000 -49.7 -57.5 245 20 10 2.2 1.2 | -50.0 -58.0 255 15 8 2.3 1.2  
38000 -48.8 -55.8 240 21 11 0.9 0.5 | -48.8 -55.8 255 17 9 1.7 0.9  
36000 -48.2 -54.8 235 23 12 0.9 0.5 | -47.8 -54.0 250 21 11 1.7 0.9  
34000 -47.6 -53.7 225 26 14 1.4 0.8 | -46.8 -52.2 250 25 13 1.6 0.9  
32000 -46.4 -51.5 225 25 13 2.0 1.1 | -45.9 -50.6 245 25 13 1.5 0.8  
30000 -44.9 -48.8 225 24 12 6.2 3.4 | -44.6 -48.3 240 24 12 6.4 3.5  
29000 -43.0 -45.4 225 23 12 6.0 3.3 | -42.7 -44.9 245 23 12 6.2 3.4  
28000 -41.2 -42.2 230 21 11 6.0 3.3 | -40.9 -41.6 250 21 11 6.2 3.4  
27000 -39.4 -38.9 230 20 10 5.8 3.2 | -39.0 -38.2 255 20 10 6.0 3.3  
26000 -37.2 -35.0 230 20 10 7.8 4.3 | -36.9 -34.4 255 19 10 7.5 4.1  
25000 -34.9 -30.8 235 19 10 7.8 4.3 | -34.7 -30.5 255 19 10 7.5 4.1  
24000 -32.5 -26.5 235 19 10 7.8 4.3 | -32.4 -26.3 255 19 10 7.5 4.1  
23000 -30.1 -22.2 235 18 9 8.2 4.5 | -30.1 -22.2 250 19 10 7.8 4.3  
22000 -27.6 -17.7 235 18 9 8.2 4.5 | -27.7 -17.9 245 18 9 7.9 4.3  
21000 -25.1 -13.2 235 17 9 8.2 4.5 | -25.4 -13.7 245 18 9 7.7 4.2  
20000 -23.0 -9.4 235 16 8 6.9 3.8 | -23.8 -10.8 245 16 8 4.5 2.5  
19500 -21.9 -7.4 235 15 8 7.0 3.8 | -23.2 -9.8 250 15 8 4.5 2.5  
19000 -20.9 -5.6 235 15 8 7.0 3.8 | -22.5 -8.5 250 13 7 4.5 2.5  
18500 -19.9 -3.8 235 14 7 7.2 4.0 | -21.8 -7.2 255 12 6 4.6 2.5  
18000 -19.0 -2.2 235 13 7 4.9 2.7 | -21.2 -6.2 260 12 6 3.4 1.9  
17500 -18.2 -0.8 240 12 6 5.1 2.8 | -20.7 -5.3 270 11 6 3.5 1.9  
17000 -17.5 0.5 245 12 6 5.4 2.9 | -20.1 -4.2 275 11 6 4.1 2.3  
16500 -16.6 2.1 245 11 6 5.5 3.0 | -19.5 -3.1 285 11 5 4.5 2.5  
16000 -15.8 3.6 250 11 5 5.6 3.1 | -18.8 -1.8 295 11 5 4.6 2.5  
15500 -14.5 5.9 260 11 6 5.9 3.2 | -17.7 0.1 310 11 6 4.9 2.7  
15000 -13.6 7.5 265 11 6 5.7 3.1 | -17.0 1.4 315 12 6 6.6 3.6  
14500 -12.8 9.0 275 12 6 5.5 3.0 | -15.8 3.6 320 13 7 7.6 4.2  
14000 -11.9 10.6 280 13 7 5.2 2.8 | -14.7 5.5 325 14 7 7.1 3.9  
13500 -11.3 11.7 290 14 7 4.3 2.3 | -13.7 7.3 325 15 7 6.5 3.6  
13000 -10.6 12.9 295 15 8 4.1 2.3 | -12.8 9.0 325 15 8 6.9 3.8  
12500 -10.1 13.8 305 16 8 3.2 1.7 | -11.7 10.9 325 15 8 7.6 4.2  
12000 -9.7 14.5 310 16 8 3.6 2.0 | -10.5 13.1 325 15 8 7.1 3.9  
11500 -8.9 16.0 315 16 8 5.8 3.2 | -9.6 14.7 325 15 8 6.3 3.5  
11000 -8.1 17.4 315 16 8 5.9 3.3 | -8.7 16.3 320 14 7 6.7 3.7  
10500 -7.1 19.2 315 17 9 6.7 3.7 | -7.7 18.1 315 13 7 7.4 4.1  
10250 -6.6 20.1 315 17 9 7.8 4.3 | -7.1 19.2 315 12 6 6.4 3.5  
10000 -6.1 21.0 315 18 9 3.5 1.9 | -6.7 19.9 310 11 6 5.7 3.1  
9750 -6.0 21.2 315 17 9 3.7 2.0 | -6.2 20.8 310 11 6 9.0 4.9  
9500 -5.5 22.1 315 17 9 8.2 4.5 | -5.4 22.3 305 10 5 11.0 6.1  
9250 -4.9 23.2 315 16 8 7.1 3.9 | -4.7 23.5 305 10 5 9.9 5.4  
9000 -4.4 24.1 315 16 8 6.4 3.5 | -4.0 24.8 305 9 5 8.7 4.8  
8750 -4.0 24.8 315 15 8 6.1 3.4 | -3.3 26.1 300 9 5 9.8 5.4  
8500 -3.5 25.7 310 15 8 6.8 3.7 | -2.5 27.5 300 9 5 11.2 6.1  
8250 -3.0 26.6 310 14 7 7.0 3.8 | -1.7 28.9 300 9 4 10.1 5.5  
8000 -2.5 27.5 310 13 7 8.0 4.4 | -1.0 30.2 300 9 4 9.2 5.0  
7750 -1.9 28.6 310 12 6 7.7 4.2 | -0.3 31.5 300 9 4 10.1 5.5  
7500 -1.4 29.5 310 12 6 6.9 3.8 | 0.5 32.9 300 8 4 10.7 5.9  
7250 -0.8 30.6 305 11 5 8.0 4.4 | 1.3 34.3 300 8 4 10.3 5.7  
7000 -0.2 31.6 305 10 5 8.8 4.8 | 2.1 35.8 300 8 4 10.4 5.7  
6750 0.4 32.7 305 9 5 8.8 4.8 | 2.8 37.0 300 8 4 10.0 5.5  
6500 1.1 34.0 300 8 4 9.7 5.3 | 3.6 38.5 300 8 4 10.2 5.6  
6250 1.9 35.4 300 8 4 10.4 5.7 | 4.4 39.9 300 8 4 11.1 6.1  
6000 2.7 36.9 300 7 4 10.4 5.7 | 5.2 41.4 300 8 4 10.0 5.5  
5750 3.5 38.3 300 7 4 11.1 6.1 | 6.0 42.8 300 7 4 13.6 7.5  
5500 4.4 39.9 295 6 3 14.8 8.1 | 7.4 45.3 300 7 4 24.2 13.3  
 
10/21/2017 AT 1500 MDT | 10/21/2017 AT 1800 MDT  
|  
CAPE... 0.0 LI... +5.3 | CAPE... 0.0 LI... +7.8  
CINH... 0.0 K INDEX... -7.9 | CINH... 0.0 K INDEX... -8.4  
|  
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 -55.7 -68.3 240 15 8 0.9 0.5 | -56.1 -69.0 280 14 7 1.2 0.7  
45000 -54.2 -65.6 275 16 8 2.5 1.4 | -54.2 -65.6 295 17 9 2.8 1.5  
40000 -49.8 -57.6 285 15 8 2.9 1.6 | -50.1 -58.2 305 19 10 2.8 1.5  
38000 -48.5 -55.3 290 17 9 1.5 0.8 | -49.1 -56.4 310 20 10 0.5 0.3  
36000 -47.6 -53.7 290 20 10 1.5 0.8 | -48.8 -55.8 315 22 11 0.5 0.3  
34000 -46.7 -52.1 290 23 12 1.4 0.7 | -48.4 -55.1 320 24 12 2.7 1.5  
32000 -45.9 -50.6 290 23 12 1.3 0.7 | -46.1 -51.0 320 26 14 3.3 1.8  
30000 -44.8 -48.6 285 24 12 6.5 3.5 | -43.9 -47.0 325 28 14 5.8 3.2  
29000 -43.0 -45.4 285 23 12 5.9 3.3 | -42.2 -44.0 325 27 14 5.7 3.1  
28000 -41.2 -42.2 285 23 12 5.9 3.2 | -40.5 -40.9 320 27 14 5.7 3.1  
27000 -39.4 -38.9 285 23 12 5.8 3.2 | -38.8 -37.8 320 26 13 5.8 3.2  
26000 -37.1 -34.8 285 22 11 8.2 4.5 | -36.8 -34.2 320 25 13 6.8 3.7  
25000 -34.7 -30.5 285 20 10 8.2 4.5 | -34.7 -30.5 315 23 12 6.8 3.7  
24000 -32.2 -26.0 285 19 10 8.3 4.5 | -32.7 -26.9 315 22 11 6.7 3.7  
23000 -30.1 -22.2 290 19 10 6.9 3.8 | -30.2 -22.4 315 21 11 8.8 4.8  
22000 -28.0 -18.4 295 19 10 6.8 3.8 | -27.5 -17.5 315 21 11 8.8 4.8  
21000 -25.9 -14.6 300 19 10 6.6 3.6 | -24.9 -12.8 315 20 10 8.1 4.4  
20000 -24.3 -11.7 300 18 9 5.3 2.9 | -22.7 -8.9 315 21 11 7.1 3.9  
19500 -23.5 -10.3 300 18 9 5.3 2.9 | -21.7 -7.1 315 22 11 7.1 3.9  
19000 -22.7 -8.9 305 17 9 5.3 2.9 | -20.6 -5.1 315 22 12 7.1 3.9  
18500 -21.9 -7.4 305 17 9 5.3 2.9 | -19.5 -3.1 315 23 12 6.4 3.5  
18000 -21.1 -6.0 305 17 9 4.9 2.7 | -18.9 -2.0 315 22 11 3.4 1.8  
17500 -20.4 -4.7 305 16 8 5.0 2.7 | -18.4 -1.1 315 21 11 3.6 2.0  
17000 -19.7 -3.5 305 16 8 4.2 2.3 | -17.9 -0.2 315 20 10 2.0 1.1  
16500 -19.1 -2.4 310 16 8 4.1 2.2 | -17.5 0.5 315 17 9 1.8 1.0  
16000 -18.1 -0.6 310 15 8 5.3 2.9 | -17.0 1.4 315 15 8 4.0 2.2  
15500 -17.3 0.9 310 15 8 5.2 2.9 | -16.5 2.3 310 13 7 3.6 2.0  
15000 -16.5 2.3 315 15 8 6.1 3.3 | -15.8 3.6 310 12 6 6.1 3.3  
14500 -15.6 3.9 315 15 8 6.3 3.5 | -14.9 5.2 310 11 6 6.3 3.4  
14000 -14.7 5.5 315 14 7 5.9 3.3 | -13.9 7.0 305 11 6 7.4 4.1  
13500 -13.8 7.2 310 14 7 5.7 3.1 | -12.7 9.1 305 12 6 7.8 4.3  
13000 -13.0 8.6 305 13 7 6.6 3.6 | -11.6 11.1 305 13 7 7.1 3.9  
12500 -11.9 10.6 305 12 6 7.6 4.1 | -10.6 12.9 300 14 7 6.7 3.7  
12000 -10.8 12.6 300 11 6 8.5 4.7 | -9.6 14.7 295 15 8 7.1 3.9  
11500 -9.4 15.1 300 10 5 9.4 5.2 | -8.6 16.5 290 15 8 7.3 4.0  
11000 -8.0 17.6 300 10 5 9.9 5.4 | -7.5 18.5 290 15 8 8.9 4.9  
10500 -6.5 20.3 300 9 5 11.0 6.0 | -6.1 21.0 290 14 7 10.3 5.7  
10250 -5.8 21.6 300 9 5 7.0 3.9 | -5.4 22.3 290 13 7 5.8 3.2  
10000 -5.4 22.3 300 9 5 6.1 3.4 | -5.1 22.8 290 13 7 5.5 3.0  
9750 -4.7 23.5 300 9 5 11.3 6.2 | -4.4 24.1 290 13 7 11.6 6.4  
9500 -3.8 25.2 300 9 5 12.1 6.6 | -3.5 25.7 290 13 6 12.7 6.9  
9250 -2.9 26.8 300 9 5 10.8 5.9 | -2.6 27.3 290 12 6 9.9 5.4  
9000 -2.2 28.0 295 9 5 9.3 5.1 | -2.0 28.4 290 12 6 7.4 4.1  
8750 -1.5 29.3 295 9 5 10.0 5.5 | -1.3 29.7 295 12 6 10.1 5.5  
8500 -0.7 30.7 295 9 5 10.6 5.8 | -0.5 31.1 295 11 6 11.1 6.1  
8250 0.1 32.2 295 9 5 10.2 5.6 | 0.3 32.5 295 11 6 9.8 5.4  
8000 0.8 33.4 295 9 5 10.1 5.5 | 1.0 33.8 295 11 6 9.0 5.0  
7750 1.6 34.9 295 9 4 9.4 5.2 | 1.7 35.1 295 10 5 10.4 5.7  
7500 2.3 36.1 295 9 4 9.3 5.1 | 2.5 36.5 295 10 5 10.5 5.8  
7250 3.0 37.4 295 9 4 10.3 5.6 | 3.2 37.8 295 10 5 9.4 5.2  
7000 3.8 38.8 295 8 4 10.8 5.9 | 3.9 39.0 295 10 5 9.4 5.2  
6750 4.6 40.3 295 8 4 9.6 5.2 | 4.6 40.3 295 9 5 9.3 5.1  
6500 5.3 41.5 295 8 4 10.0 5.5 | 5.3 41.5 295 9 5 9.4 5.1  
6250 6.1 43.0 295 8 4 11.6 6.4 | 6.0 42.8 295 9 4 9.4 5.2  
6000 6.9 44.4 295 8 4 10.6 5.8 | 6.7 44.1 295 8 4 9.7 5.3  
5750 7.8 46.0 295 8 4 13.2 7.2 | 7.4 45.3 295 7 4 8.4 4.6  
5500 9.0 48.2 295 7 4 20.7 11.4 | 7.9 46.2 295 6 3 5.0 2.7  
________________________________________________________________________________  
 
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 NEAR THE OLD STAPLETON  
AIRPORT SITE IN DENVER, COLORADO AT  
 
NORTH LATITUDE: 39 DEG 46 MIN 5.016 SEC  
WEST LONGITUDE: 104 DEG 52 MIN 9.984 SEC  
ELEVATION: 5285 FEET (1611 METERS)  
 
AND MAY NOT BE REPRESENTATIVE OF OTHER AREAS ALONG THE FRONT RANGE OF THE  
COLORADO ROCKY MOUNTAINS. 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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