717
UXUS97 KBOU 181313
SRGBOU
SOARING FORECAST
NATIONAL WEATHER SERVICE DENVER/BOULDER, COLORADO
0612 MST THURSDAY, DECEMBER 18, 2025
THIS FORECAST IS FOR THURSDAY, DECEMBER 18, 2025:
IF THE TRIGGER TEMPERATURE OF 36.7 F/2.6 C IS REACHED...THEN
THERMAL SOARING INDEX....................... GOOD
MAXIMUM RATE OF LIFT........................ 652 FT/MIN (3.3 M/S)
MAXIMUM HEIGHT OF THERMALS.................. 13759 FT MSL (8461 FT AGL)
FORECAST MAXIMUM TEMPERATURE................... 47.0 F/8.8 C
TIME OF TRIGGER TEMPERATURE.................... 0900 MST
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................. 12058 FT MSL (6760 FT AGL)
THERMAL SOARING OUTLOOK FOR FRIDAY 12/19....... GOOD
WAVE SOARING INDEX............................. POOR
WAVE SOARING INDEX TREND (TO 1700 MST).........
HEIGHT OF STABLE LAYER (12-18K FT MSL)......... 17109 FT MSL (11811 FT AGL)
WEAK PVA/NVA (THROUGH 1700 MST)................ WEAK NVA
POTENTIAL HEIGHT OF WAVE....................... 30150 FT MSL (24852 FT AGL)
WAVE SOARING OUTLOOK FOR FRIDAY 12/19.......... FAIR
REMARKS...
SUNRISE/SUNSET.................... 07:15:46 / 16:36:55 MST
TOTAL POSSIBLE SUNSHINE........... 9 HR 21 MIN 10 SEC (561 MIN 10 SEC)
ALTITUDE OF SUN AT 11:56:20 MST... 26.82 DEGREES
UPPER AIR DATA FROM NUMERICAL MODEL FORECAST VALID ON 12/18/2025 AT 0500 MST
FREEZING LEVEL.................. 5531 FT MSL (233 FT AGL)
ADDITIONAL FREEZING LEVEL....... 5553 FT MSL (255 FT AGL)
CONVECTIVE CONDENSATION LEVEL... 14420 FT MSL (9122 FT AGL)
LIFTED CONDENSATION LEVEL....... 14172 FT MSL (8874 FT AGL)
LIFTED INDEX.................... +14.2
K INDEX......................... -26.4
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 -58.0 -72.4 285 59 31 2.2 1.2 M M M M M
45000 -54.5 -66.1 310 76 39 2.5 1.3 M M M M M
40000 -54.1 -65.4 310 85 44 0.1 0.1 M M M M M
38000 -53.6 -64.5 310 92 47 2.1 1.2 M M M M M
36000 -52.4 -62.3 320 105 54 2.1 1.2 M M M M M
34000 -51.1 -60.0 325 120 62 2.1 1.1 M M M M M
32000 -47.9 -54.2 325 130 67 5.6 3.1 M M M M M
30000 -44.1 -47.4 325 141 72 7.3 4.0 33.2 91.8 18.6 M M
29000 -41.7 -43.1 325 137 70 8.3 4.5 32.5 90.5 18.3 M M
28000 -39.2 -38.6 325 133 68 8.3 4.6 31.9 89.4 18.1 M M
27000 -36.7 -34.1 325 129 66 8.3 4.6 31.4 88.6 17.9 M M
26000 -34.2 -29.6 325 126 65 8.4 4.6 30.9 87.6 17.7 M M
25000 -31.6 -24.9 325 125 64 8.4 4.6 30.3 86.6 17.5 M M
24000 -29.1 -20.4 325 123 63 8.4 4.6 29.9 85.8 17.3 M M
23000 -27.1 -16.8 325 119 61 4.2 2.3 28.8 83.9 16.7 M M
22000 -25.8 -14.4 325 111 57 4.3 2.4 26.8 80.2 15.2 M M
21000 -24.5 -12.1 320 103 53 4.3 2.4 24.9 76.8 13.8 M M
20000 -23.3 -9.9 320 97 50 3.3 1.8 22.7 72.9 12.2 M M
19500 -22.8 -9.0 320 94 48 3.3 1.8 21.5 70.8 11.2 M M
19000 -22.4 -8.3 315 91 47 3.3 1.8 20.4 68.7 10.3 M M
18500 -21.9 -7.4 315 88 45 3.2 1.8 19.3 66.7 9.4 M M
18000 -21.4 -6.5 315 85 44 2.7 1.5 18.2 64.8 8.6 M M
17500 -21.1 -6.0 315 81 42 2.0 1.1 16.9 62.4 7.4 M M
17000 -20.8 -5.4 315 78 40 1.9 1.0 15.5 60.0 6.3 M M
16500 -20.4 -4.7 315 74 38 3.5 1.9 14.3 57.8 5.3 M M
16000 -19.6 -3.3 310 70 36 3.3 1.8 12.7 54.9 3.9 M M
15500 -19.2 -2.6 310 66 34 2.8 1.5 11.6 52.8 2.9 M M
15000 -18.8 -1.8 310 61 32 2.7 1.5 10.4 50.7 1.8 M M
14500 -18.2 -0.8 310 58 30 5.1 2.8 9.4 49.0 1.0 M M
14000 -17.5 0.5 310 56 29 4.9 2.7 8.6 47.5 0.2 M M
13500 -16.8 1.8 315 55 28 4.5 2.5 7.8 46.0 -0.5 628 3.2
13000 -16.1 3.0 315 57 30 4.7 2.6 6.9 44.5 -1.4 593 3.0
12500 -15.5 4.1 315 57 29 3.4 1.8 6.0 42.8 -2.2 561 2.8
12000 -15.0 5.0 315 52 27 3.0 1.6 5.0 41.0 -3.2 531 2.7
11500 -14.3 6.3 315 49 25 7.9 4.3 4.3 39.7 -4.0 494 2.5
11000 -13.1 8.4 320 47 24 7.9 4.3 3.9 39.1 -4.3 445 2.3
10500 -12.1 10.2 315 45 23 6.9 3.8 3.6 38.4 -4.7 398 2.0
10250 -11.5 11.3 315 44 23 6.5 3.6 3.3 38.0 -4.9 375 1.9
10000 -11.0 12.2 315 43 22 8.4 4.6 3.1 37.6 -5.2 352 1.8
9750 -10.3 13.5 315 41 21 9.3 5.1 3.1 37.6 -5.2 324 1.6
9500 -9.7 14.5 315 41 21 8.1 4.4 3.0 37.3 -5.4 298 1.5
9250 -9.1 15.6 315 40 20 8.2 4.5 2.9 37.1 -5.5 272 1.4
9000 -8.5 16.7 315 39 20 8.9 4.9 2.7 36.9 -5.6 246 1.3
8750 -7.8 18.0 315 38 19 9.3 5.1 2.7 36.9 -5.7 218 1.1
8500 -7.1 19.2 315 37 19 8.9 4.9 2.7 36.8 -5.7 191 1.0
8250 -6.5 20.3 315 36 18 8.9 4.9 2.6 36.7 -5.8 163 0.8
8000 -5.8 21.6 310 35 18 9.3 5.1 2.5 36.6 -5.9 136 0.7
7750 -5.1 22.8 310 33 17 8.6 4.7 2.5 36.5 -5.9 108 0.5
7500 -4.5 23.9 310 32 16 7.6 4.2 2.4 36.2 -6.1 83 0.4
7250 -3.9 25.0 310 30 16 8.1 4.5 2.2 36.0 -6.3 58 0.3
7000 -3.3 26.1 310 29 15 8.7 4.8 2.1 35.8 -6.4 31 0.2
6750 -2.6 27.3 310 27 14 8.4 4.6 2.0 35.7 -6.5 5 0.0
6500 -2.0 28.4 310 26 13 8.0 4.4 1.9 35.4 -6.6 M M
6250 -1.5 29.3 310 24 12 7.6 4.2 1.8 35.2 -6.8 M M
6000 -0.9 30.4 305 21 11 7.7 4.2 1.6 34.9 -7.0 M M
5750 -0.3 31.5 300 18 10 6.9 3.8 1.4 34.6 -7.2 M M
5500 0.0 32.0 300 15 8 1.8 1.0 1.1 33.9 -7.6 M M
* * * * * * NUMERICAL WEATHER PREDICTION MODEL FORECAST DATA VALID * * * * * *
12/18/2025 AT 0800 MST | 12/18/2025 AT 1100 MST
|
CAPE... 0.0 LI... +14.0 | CAPE... 0.0 LI... +11.9
CINH... 0.0 K INDEX... -36.0 | CINH... 0.0 K INDEX... -31.7
|
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 -59.2 -74.6 295 61 31 1.4 0.8 | -60.3 -76.5 300 53 27 0.9 0.5
45000 -57.0 -70.6 310 79 41 1.6 0.9 | -58.8 -73.8 305 70 36 0.9 0.5
40000 -57.4 -71.3 315 81 42 -0.4 -0.2 | -58.2 -72.8 310 96 49 0.4 0.2
38000 -56.9 -70.4 315 88 45 3.4 1.9 | -57.0 -70.6 310 106 54 4.3 2.4
36000 -54.8 -66.6 320 111 57 3.4 1.9 | -54.4 -65.9 320 116 60 4.3 2.4
34000 -52.8 -63.0 325 135 69 5.4 3.0 | -51.7 -61.1 325 126 65 7.1 3.9
32000 -47.3 -53.1 325 135 69 8.1 4.5 | -46.4 -51.5 320 124 64 7.9 4.3
30000 -42.5 -44.5 325 133 69 7.0 3.8 | -41.6 -42.9 320 121 63 7.6 4.2
29000 -40.5 -40.9 325 128 66 6.8 3.8 | -39.4 -38.9 320 120 62 7.7 4.2
28000 -38.4 -37.1 320 124 64 6.9 3.8 | -37.1 -34.8 320 119 61 7.7 4.2
27000 -36.4 -33.5 320 119 61 6.8 3.7 | -34.8 -30.6 320 118 61 7.7 4.2
26000 -34.3 -29.7 320 113 58 7.2 4.0 | -32.7 -26.9 320 115 59 6.6 3.6
25000 -32.1 -25.8 320 107 55 7.2 4.0 | -30.8 -23.4 325 112 57 6.6 3.6
24000 -29.9 -21.8 320 101 52 7.2 4.0 | -28.8 -19.8 325 108 56 6.6 3.6
23000 -27.7 -17.9 325 97 50 7.5 4.1 | -26.9 -16.4 325 101 52 6.3 3.5
22000 -25.5 -13.9 325 95 49 7.5 4.1 | -25.0 -13.0 320 92 47 6.3 3.5
21000 -23.2 -9.8 325 92 48 7.7 4.2 | -23.2 -9.8 320 82 42 6.3 3.5
20000 -21.4 -6.5 325 89 46 5.3 2.9 | -21.5 -6.7 315 77 40 5.3 2.9
19500 -20.6 -5.1 325 88 45 5.3 2.9 | -20.7 -5.3 315 75 39 5.3 2.9
19000 -19.8 -3.6 325 86 44 5.3 2.9 | -20.0 -4.0 315 73 38 5.3 2.9
18500 -19.0 -2.2 325 85 44 5.3 2.9 | -19.2 -2.6 315 71 37 5.4 3.0
18000 -18.2 -0.8 325 83 43 5.2 2.9 | -18.4 -1.1 315 69 36 4.2 2.3
17500 -17.5 0.5 320 81 41 5.2 2.8 | -17.4 0.7 315 64 33 4.2 2.3
17000 -16.3 2.7 320 77 39 4.7 2.6 | -16.8 1.8 315 62 32 4.6 2.5
16500 -15.6 3.9 320 74 38 4.6 2.5 | -16.1 3.0 315 59 31 4.6 2.5
16000 -14.9 5.2 320 71 36 3.5 1.9 | -15.4 4.3 315 57 29 4.7 2.6
15500 -14.6 5.7 320 68 35 2.0 1.1 | -14.7 5.5 315 54 28 4.7 2.6
15000 -14.3 6.3 320 65 34 1.5 0.8 | -13.9 7.0 315 51 26 4.6 2.5
14500 -14.4 6.1 320 61 31 -2.6 -1.4 | -13.3 8.1 315 49 25 4.4 2.4
14000 -14.8 5.4 315 56 29 -2.4 -1.3 | -12.6 9.3 315 46 24 4.3 2.4
13500 -15.1 4.8 315 50 26 -1.1 -0.6 | -12.0 10.4 315 43 22 3.9 2.2
13000 -15.2 4.6 320 44 23 -1.7 -1.0 | -11.4 11.5 310 41 21 3.8 2.1
12500 -15.1 4.8 320 39 20 4.1 2.2 | -11.1 12.0 310 37 19 1.1 0.6
12000 -14.6 5.7 325 37 19 3.1 1.7 | -10.9 12.4 310 32 16 1.6 0.9
11500 -13.7 7.3 325 37 19 8.8 4.8 | -10.3 13.5 310 30 15 6.4 3.5
11000 -12.5 9.5 325 38 20 8.2 4.5 | -9.4 15.1 310 29 15 6.1 3.3
10500 -11.7 10.9 325 35 18 3.3 1.8 | -8.4 16.9 305 30 15 6.3 3.5
10250 -11.4 11.5 325 33 17 4.4 2.4 | -7.9 17.8 305 30 16 7.7 4.2
10000 -11.1 12.0 320 30 16 2.5 1.3 | -7.4 18.7 305 31 16 2.5 1.4
9750 -11.0 12.2 320 29 15 5.0 2.7 | -7.5 18.5 305 30 15 -0.3 -0.1
9500 -10.4 13.3 320 28 15 8.6 4.7 | -7.4 18.7 300 29 15 2.9 1.6
9250 -9.8 14.4 320 28 15 7.6 4.1 | -7.2 19.0 300 29 15 2.0 1.1
9000 -9.2 15.4 315 28 15 8.2 4.5 | -7.1 19.2 300 28 14 2.6 1.5
8750 -8.6 16.5 315 27 14 8.1 4.4 | -6.9 19.6 300 25 13 3.2 1.7
8500 -8.0 17.6 315 26 14 7.6 4.2 | -6.6 20.1 300 22 11 3.0 1.7
8250 -7.5 18.5 315 26 13 8.0 4.4 | -6.4 20.5 300 19 10 3.8 2.1
8000 -6.8 19.8 315 24 13 9.9 5.4 | -6.1 21.0 300 15 8 5.9 3.2
7750 -6.0 21.2 315 23 12 9.5 5.2 | -5.6 21.9 300 11 6 6.7 3.7
7500 -5.4 22.3 315 22 11 7.6 4.2 | -5.1 22.8 305 9 5 6.2 3.4
7250 -4.8 23.4 315 21 11 8.8 4.8 | -4.6 23.7 305 7 3 8.8 4.8
7000 -4.1 24.6 320 19 10 10.0 5.5 | -3.8 25.2 305 6 3 11.6 6.4
6750 -3.4 25.9 320 18 9 8.6 4.7 | -3.0 26.6 310 6 3 9.0 4.9
6500 -2.8 27.0 320 17 8 7.2 3.9 | -2.4 27.7 310 5 3 8.7 4.8
6250 -2.3 27.9 320 15 8 7.1 3.9 | -1.6 29.1 310 5 3 11.1 6.1
6000 -1.8 28.8 315 13 7 7.5 4.1 | -0.8 30.6 310 5 3 11.1 6.1
5750 -1.2 29.8 310 11 6 5.8 3.2 | 0.0 32.0 310 5 2 11.3 6.2
5500 -1.0 30.2 305 8 4 0.5 0.3 | 1.0 33.8 310 5 2 15.0 8.2
12/18/2025 AT 1400 MST | 12/18/2025 AT 1700 MST
|
CAPE... 0.0 LI... +11.6 | CAPE... 0.0 LI... +9.5
CINH... 0.0 K INDEX... -12.1 | CINH... 0.0 K INDEX... -3.0
|
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 -78.0 300 57 29 0.1 0.1 | -61.5 -78.7 310 53 28 0.3 0.2
45000 -61.0 -77.8 305 67 35 0.2 0.1 | -61.1 -78.0 310 69 36 0.5 0.3
40000 -60.3 -76.5 300 92 48 0.4 0.2 | -59.1 -74.4 295 102 53 1.4 0.7
38000 -58.4 -73.1 305 100 52 6.4 3.5 | -57.4 -71.3 300 107 55 4.4 2.4
36000 -54.5 -66.1 320 108 56 6.4 3.5 | -54.4 -65.9 315 105 54 4.4 2.4
34000 -50.0 -58.0 325 118 61 7.5 4.1 | -51.2 -60.2 325 107 55 7.6 4.2
32000 -45.5 -49.9 325 115 59 7.5 4.1 | -46.6 -51.9 320 103 53 7.7 4.2
30000 -41.0 -41.8 320 113 58 7.7 4.2 | -41.8 -43.2 315 100 52 9.0 4.9
29000 -38.7 -37.7 315 111 57 7.7 4.2 | -39.1 -38.4 315 99 51 9.1 5.0
28000 -36.4 -33.5 315 109 56 7.7 4.2 | -36.4 -33.5 310 98 51 9.1 5.0
27000 -34.1 -29.4 315 107 55 7.6 4.2 | -33.6 -28.5 310 97 50 8.5 4.7
26000 -31.9 -25.4 315 102 53 7.4 4.1 | -31.3 -24.3 310 95 49 7.8 4.3
25000 -29.7 -21.5 315 98 50 7.4 4.1 | -29.0 -20.2 310 93 48 7.8 4.3
24000 -27.5 -17.5 315 93 48 7.6 4.2 | -26.6 -15.9 310 91 47 7.8 4.3
23000 -25.5 -13.9 315 84 43 6.1 3.3 | -24.6 -12.3 310 87 45 6.8 3.7
22000 -23.7 -10.7 315 74 38 6.1 3.4 | -22.6 -8.7 310 82 42 6.8 3.7
21000 -21.9 -7.4 315 64 33 6.4 3.5 | -20.5 -4.9 310 77 40 6.6 3.6
20000 -19.7 -3.5 315 62 32 7.5 4.1 | -18.7 -1.7 305 71 37 6.3 3.5
19500 -18.6 -1.5 310 61 32 7.5 4.1 | -17.8 -0.0 305 68 35 6.3 3.5
19000 -17.5 0.5 310 61 31 7.5 4.1 | -16.8 1.8 305 65 34 6.3 3.5
18500 -16.3 2.7 310 60 31 7.5 4.1 | -15.9 3.4 305 62 32 6.3 3.4
18000 -15.4 4.3 310 60 31 5.8 3.2 | -14.7 5.5 305 57 29 5.4 2.9
17500 -14.5 5.9 310 60 31 5.9 3.3 | -13.9 7.0 305 52 27 5.4 2.9
17000 -13.3 8.1 310 59 30 4.7 2.6 | -13.1 8.4 305 49 25 5.6 3.1
16500 -12.6 9.3 315 59 30 4.8 2.7 | -12.2 10.0 305 45 23 5.7 3.1
16000 -11.9 10.6 315 58 30 3.4 1.9 | -11.4 11.5 305 41 21 5.0 2.7
15500 -11.5 11.3 315 55 29 3.1 1.7 | -10.7 12.7 305 38 20 5.0 2.7
15000 -11.0 12.2 315 53 27 3.3 1.8 | -9.9 14.2 310 35 18 5.3 2.9
14500 -10.5 13.1 315 51 26 3.6 2.0 | -9.1 15.6 310 34 18 5.6 3.1
14000 -9.9 14.2 315 48 25 3.7 2.0 | -8.2 17.2 310 33 17 5.5 3.0
13500 -9.3 15.3 310 46 23 3.9 2.2 | -7.4 18.7 305 34 17 5.2 2.8
13000 -8.7 16.3 310 43 22 3.8 2.1 | -6.6 20.1 305 34 18 5.0 2.8
12500 -8.2 17.2 305 41 21 3.1 1.7 | -5.9 21.4 300 36 19 4.3 2.4
12000 -7.7 18.1 305 38 20 3.3 1.8 | -5.2 22.6 300 38 20 4.1 2.2
11500 -7.0 19.4 300 38 19 4.9 2.7 | -4.8 23.4 295 38 20 2.0 1.1
11000 -6.3 20.7 300 38 20 4.7 2.6 | -4.4 24.1 290 38 19 2.3 1.3
10500 -5.7 21.7 295 37 19 3.7 2.0 | -4.0 24.8 290 36 19 3.3 1.8
10250 -5.4 22.3 295 37 19 4.4 2.4 | -3.7 25.3 290 35 18 2.3 1.3
10000 -5.1 22.8 290 36 19 2.0 1.1 | -3.5 25.7 285 34 18 5.7 3.1
9750 -5.1 22.8 290 34 17 1.7 0.9 | -3.0 26.6 285 32 16 5.7 3.1
9500 -4.8 23.4 285 31 16 3.7 2.0 | -2.7 27.1 285 29 15 2.4 1.3
9250 -4.6 23.7 285 29 15 3.4 1.9 | -2.5 27.5 280 27 14 3.0 1.6
9000 -4.3 24.3 280 27 14 2.7 1.5 | -2.3 27.9 280 24 12 3.9 2.1
8750 -4.2 24.4 280 23 12 3.2 1.8 | -1.9 28.6 280 21 11 5.0 2.8
8500 -3.9 25.0 280 20 10 4.6 2.5 | -1.5 29.3 275 18 9 4.6 2.5
8250 -3.6 25.5 280 17 8 4.2 2.3 | -1.2 29.8 275 16 8 4.9 2.7
8000 -3.3 26.1 275 13 7 3.5 1.9 | -0.8 30.6 270 13 7 5.2 2.9
7750 -3.0 26.6 265 9 5 4.1 2.3 | -0.4 31.3 255 9 5 5.7 3.1
7500 -2.7 27.1 250 7 4 3.9 2.2 | 0.0 32.0 245 8 4 5.5 3.0
7250 -2.4 27.7 230 5 3 7.2 4.0 | 0.4 32.7 225 7 4 6.5 3.6
7000 -1.6 29.1 225 5 3 11.3 6.2 | 1.0 33.8 210 7 4 7.6 4.2
6750 -0.8 30.6 220 5 2 9.3 5.1 | 1.5 34.7 195 8 4 7.6 4.2
6500 -0.2 31.6 215 5 2 9.3 5.1 | 2.1 35.8 180 9 4 6.9 3.8
6250 0.6 33.1 215 5 2 10.9 6.0 | 2.5 36.5 170 9 5 5.1 2.8
6000 1.4 34.5 215 5 2 11.4 6.3 | 2.8 37.0 160 9 5 4.2 2.3
5750 2.3 36.1 210 4 2 10.4 5.7 | 3.2 37.8 150 9 5 5.5 3.0
5500 3.1 37.6 210 4 2 11.8 6.5 | 3.6 38.5 145 8 4 4.6 2.5
________________________________________________________________________________
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.
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