694
UXUS97 KBOU 130016
SRGBOU
SOARING FORECAST
NATIONAL WEATHER SERVICE DENVER/BOULDER, COLORADO
1715 MST WEDNESDAY, NOVEMBER 12, 2025
THIS FORECAST IS FOR THURSDAY, NOVEMBER 13, 2025:
IF THE TRIGGER TEMPERATURE OF 67.1 F/19.5 C IS REACHED...THEN
THERMAL SOARING INDEX....................... EXCELLENT
MAXIMUM RATE OF LIFT........................ 838 FT/MIN (4.3 M/S)
MAXIMUM HEIGHT OF THERMALS.................. 14910 FT MSL (9597 FT AGL)
FORECAST MAXIMUM TEMPERATURE................... 74.0 F/23.8 C
TIME OF TRIGGER TEMPERATURE.................... 1045 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................. 10695 FT MSL (5383 FT AGL)
THERMAL SOARING OUTLOOK FOR FRIDAY 11/14....... GOOD
WAVE SOARING INDEX............................. POOR
WAVE SOARING INDEX TREND (TO 1700 MST)......... NO CHANGE
HEIGHT OF STABLE LAYER (12-18K FT MSL)......... NONE
WEAK PVA/NVA (THROUGH 1700 MST)................ NEITHER
POTENTIAL HEIGHT OF WAVE....................... 39809 FT MSL (34496 FT AGL)
WAVE SOARING OUTLOOK FOR FRIDAY 11/14.......... POOR
REMARKS...
SUNRISE/SUNSET.................... 06:42:30 / 16:45:05 MST
TOTAL POSSIBLE SUNSHINE........... 10 HR 2 MIN 36 SEC (602 MIN 36 SEC)
ALTITUDE OF SUN AT 11:43:48 MST... 31.93 DEGREES
UPPER AIR DATA FROM NUMERICAL MODEL FORECAST VALID ON 11/13/2025 AT 0500 MST
FREEZING LEVEL.................. 12455 FT MSL (7142 FT AGL)
CONVECTIVE CONDENSATION LEVEL... 17803 FT MSL (12490 FT AGL)
LIFTED CONDENSATION LEVEL....... 16734 FT MSL (11422 FT AGL)
LIFTED INDEX.................... +4.1
K INDEX......................... +15.2
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 -65.2 -85.4 275 45 23 2.8 1.5 M M M M M
45000 -61.3 -78.3 275 58 30 1.8 1.0 M M M M M
40000 -58.6 -73.5 270 79 41 2.2 1.2 M M M M M
38000 -54.6 -66.3 270 78 40 7.1 3.9 M M M M M
36000 -50.3 -58.5 270 77 40 7.1 3.9 M M M M M
34000 -44.9 -48.8 270 77 39 8.7 4.8 M M M M M
32000 -39.7 -39.5 270 77 39 8.7 4.8 M M M M M
30000 -34.7 -30.5 270 73 38 8.0 4.4 41.8 107.3 14.0 M M
29000 -32.3 -26.1 270 71 36 8.0 4.4 41.1 106.0 13.6 M M
28000 -29.9 -21.8 270 68 35 8.1 4.5 40.6 105.0 13.3 M M
27000 -27.9 -18.2 275 64 33 5.8 3.2 39.3 102.8 12.5 M M
26000 -26.2 -15.2 275 59 30 5.8 3.2 37.8 100.0 11.4 M M
25000 -24.5 -12.1 275 54 28 5.8 3.2 36.3 97.4 10.3 M M
24000 -22.7 -8.9 275 49 25 6.6 3.6 35.0 95.1 9.4 M M
23000 -20.7 -5.3 275 45 23 6.6 3.6 33.8 92.9 8.5 M M
22000 -18.7 -1.7 275 41 21 6.6 3.6 32.8 91.0 7.6 M M
21000 -16.9 1.6 270 38 20 5.9 3.2 31.5 88.7 6.6 M M
20000 -15.2 4.6 270 36 18 5.9 3.2 30.1 86.1 5.5 M M
19500 -14.3 6.3 270 35 18 5.9 3.2 29.4 85.0 4.9 M M
19000 -13.5 7.7 270 34 17 5.9 3.2 28.8 83.8 4.4 M M
18500 -12.6 9.3 270 33 17 5.9 3.2 28.1 82.6 3.8 M M
18000 -11.3 11.7 275 32 16 5.9 3.2 27.1 80.8 3.0 M M
17500 -10.5 13.1 275 31 16 5.9 3.2 26.4 79.6 2.4 M M
17000 -9.6 14.7 275 30 15 5.8 3.2 25.8 78.4 1.8 M M
16500 -8.7 16.3 275 29 15 6.9 3.8 25.2 77.4 1.2 M M
16000 -7.6 18.3 275 28 14 7.0 3.8 24.7 76.5 0.8 M M
15500 -6.6 20.1 280 27 14 7.3 4.0 24.3 75.7 0.4 M M
15000 -5.5 22.1 280 26 13 7.5 4.1 23.9 75.0 0.0 M M
14500 -4.4 24.1 280 25 13 7.5 4.1 23.5 74.3 -0.3 792 4.0
14000 -3.3 26.1 285 25 13 7.3 4.0 23.1 73.6 -0.7 744 3.8
13500 -2.2 28.0 285 25 13 7.3 4.0 22.7 72.9 -1.1 696 3.5
13000 -1.1 30.0 285 24 12 7.4 4.0 22.3 72.2 -1.5 648 3.3
12500 -0.0 32.0 285 23 12 7.4 4.0 21.9 71.5 -1.8 601 3.1
12000 1.1 34.0 285 22 11 7.5 4.1 21.6 70.8 -2.2 552 2.8
11500 2.3 36.1 290 20 11 7.5 4.1 21.2 70.2 -2.5 503 2.6
11000 3.4 38.1 290 20 10 7.9 4.3 20.9 69.6 -2.8 454 2.3
10500 4.6 40.3 290 19 10 7.7 4.2 20.6 69.1 -3.1 404 2.1
10250 5.1 41.2 290 19 10 4.7 2.6 20.3 68.6 -3.4 382 1.9
10000 5.4 41.7 290 19 10 7.6 4.2 19.9 67.9 -3.8 364 1.8
9750 6.2 43.2 290 20 10 11.8 6.5 20.0 68.1 -3.7 332 1.7
9500 7.0 44.6 290 21 11 10.2 5.6 20.1 68.2 -3.6 301 1.5
9250 7.7 45.9 290 22 11 7.1 3.9 20.1 68.1 -3.7 273 1.4
9000 8.2 46.8 290 21 11 6.5 3.6 19.8 67.6 -4.0 252 1.3
8750 8.7 47.7 290 21 11 8.4 4.6 19.6 67.3 -4.1 227 1.2
8500 9.4 48.9 290 21 11 8.0 4.4 19.5 67.1 -4.3 201 1.0
8250 9.9 49.8 290 21 11 7.8 4.3 19.4 66.9 -4.4 176 0.9
8000 10.5 50.9 290 21 11 7.7 4.2 19.2 66.6 -4.6 152 0.8
7750 11.1 52.0 290 21 11 7.9 4.3 19.1 66.3 -4.7 127 0.6
7500 11.7 53.1 290 20 10 7.3 4.0 18.9 66.0 -4.9 102 0.5
7250 12.2 54.0 290 19 10 6.6 3.6 18.7 65.6 -5.1 79 0.4
7000 12.7 54.9 290 18 9 7.0 3.8 18.4 65.2 -5.4 57 0.3
6750 13.2 55.8 290 17 9 5.8 3.2 18.2 64.8 -5.6 34 0.2
6500 13.5 56.3 290 15 8 3.3 1.8 17.8 64.1 -6.0 17 0.1
6250 13.7 56.7 285 12 6 2.3 1.2 17.3 63.1 -6.6 3 0.0
6000 13.9 57.0 285 10 5 3.4 1.9 16.7 62.1 -7.1 M M
5750 13.5 56.3 275 8 4 -26.9 -14.8 15.5 59.9 -8.3 M M
5500 9.4 48.9 245 6 3 -75.4 -41.4 10.7 51.3 -13.2 112 0.6
* * * * * * NUMERICAL WEATHER PREDICTION MODEL FORECAST DATA VALID * * * * * *
11/13/2025 AT 0800 MST | 11/13/2025 AT 1100 MST
|
CAPE... 0.0 LI... +3.6 | CAPE... 0.0 LI... +4.2
CINH... 0.0 K INDEX... +13.3 | CINH... -0.1 K INDEX... +12.8
|
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 -65.7 -86.3 285 38 20 3.0 1.6 | -65.8 -86.4 280 40 21 3.9 2.1
45000 -61.3 -78.3 280 58 30 2.3 1.2 | -60.4 -76.7 280 58 30 2.2 1.2
40000 -57.9 -72.2 275 72 37 2.3 1.3 | -57.1 -70.8 270 68 35 2.3 1.2
38000 -54.3 -65.7 275 72 37 6.5 3.6 | -53.2 -63.8 270 69 35 6.0 3.3
36000 -49.9 -57.8 275 72 37 6.5 3.6 | -49.6 -57.3 270 69 35 6.0 3.3
34000 -45.2 -49.4 275 69 36 8.5 4.7 | -45.1 -49.2 270 66 34 8.3 4.5
32000 -40.0 -40.0 275 66 34 8.5 4.7 | -40.1 -40.2 270 62 32 8.3 4.5
30000 -35.3 -31.5 275 62 32 7.4 4.1 | -35.2 -31.4 270 59 31 8.0 4.4
29000 -33.1 -27.6 275 60 31 7.4 4.1 | -32.8 -27.0 275 58 30 8.0 4.4
28000 -30.9 -23.6 275 57 29 7.4 4.1 | -30.4 -22.7 275 57 29 8.1 4.4
27000 -28.8 -19.8 275 55 28 6.7 3.7 | -28.3 -18.9 275 54 28 6.3 3.5
26000 -26.8 -16.2 275 52 27 6.7 3.7 | -26.4 -15.5 275 52 27 6.3 3.5
25000 -24.8 -12.6 275 50 26 6.7 3.7 | -24.5 -12.1 275 49 25 6.3 3.5
24000 -22.8 -9.0 275 47 24 6.6 3.6 | -22.6 -8.7 275 46 24 6.4 3.5
23000 -20.9 -5.6 275 44 22 6.6 3.6 | -20.7 -5.3 275 43 22 6.4 3.5
22000 -18.9 -2.0 275 40 21 6.6 3.6 | -18.8 -1.8 270 40 20 6.5 3.6
21000 -17.0 1.4 275 37 19 5.9 3.3 | -16.9 1.6 270 37 19 6.8 3.7
20000 -15.3 4.5 275 34 18 5.9 3.3 | -14.4 6.1 275 34 17 6.8 3.7
19500 -14.4 6.1 275 33 17 6.0 3.3 | -13.4 7.9 275 32 17 6.9 3.8
19000 -13.1 8.4 280 31 16 5.9 3.2 | -12.4 9.7 275 31 16 5.7 3.1
18500 -12.3 9.9 280 30 16 5.8 3.2 | -11.6 11.1 280 30 16 5.4 3.0
18000 -11.4 11.5 280 30 15 5.9 3.2 | -10.8 12.6 280 29 15 5.4 3.0
17500 -10.5 13.1 285 29 15 6.2 3.4 | -10.0 14.0 285 28 15 5.5 3.0
17000 -9.6 14.7 285 28 15 6.1 3.4 | -9.2 15.4 285 27 14 5.4 3.0
16500 -8.7 16.3 290 28 14 7.0 3.8 | -8.4 16.9 290 26 13 6.4 3.5
16000 -7.6 18.3 290 27 14 7.0 3.9 | -7.4 18.7 290 25 13 6.4 3.5
15500 -6.6 20.1 290 27 14 6.8 3.7 | -6.4 20.5 295 25 13 6.9 3.8
15000 -5.6 21.9 295 26 13 6.6 3.6 | -5.4 22.3 300 24 12 7.2 3.9
14500 -4.6 23.7 295 25 13 6.8 3.7 | -4.3 24.3 300 23 12 7.3 4.0
14000 -3.6 25.5 295 24 13 7.3 4.0 | -3.2 26.2 300 23 12 7.6 4.2
13500 -2.5 27.5 295 24 12 7.2 4.0 | -2.1 28.2 300 22 12 7.6 4.2
13000 -1.5 29.3 300 23 12 7.2 4.0 | -1.0 30.2 300 22 11 7.2 3.9
12500 -0.4 31.3 300 22 11 7.2 4.0 | 0.1 32.2 300 22 11 7.2 4.0
12000 0.7 33.3 300 20 11 7.5 4.1 | 1.1 34.0 300 21 11 7.2 4.0
11500 1.8 35.2 300 19 10 7.5 4.1 | 2.2 36.0 295 20 10 7.2 3.9
11000 3.0 37.4 300 18 9 8.3 4.6 | 3.3 37.9 295 18 9 8.1 4.4
10500 4.2 39.6 300 17 9 7.6 4.2 | 4.5 40.1 290 17 9 7.3 4.0
10250 4.7 40.5 300 17 9 3.2 1.8 | 4.9 40.8 290 16 8 2.9 1.6
10000 4.9 40.8 300 17 9 7.2 4.0 | 5.2 41.4 290 17 9 7.2 3.9
9750 5.8 42.4 300 19 10 13.0 7.1 | 6.0 42.8 290 18 9 12.8 7.0
9500 6.6 43.9 300 20 11 10.5 5.8 | 6.9 44.4 290 20 10 10.6 5.8
9250 7.3 45.1 300 21 11 6.2 3.4 | 7.6 45.7 290 20 10 6.4 3.5
9000 7.7 45.9 295 22 11 6.2 3.4 | 8.0 46.4 290 20 10 7.0 3.9
8750 8.3 46.9 295 21 11 9.5 5.2 | 8.7 47.7 290 20 10 11.1 6.1
8500 9.0 48.2 295 21 11 8.4 4.6 | 9.4 48.9 290 21 11 9.0 5.0
8250 9.6 49.3 295 20 10 7.0 3.9 | 10.0 50.0 290 19 10 6.5 3.6
8000 10.1 50.2 295 19 10 7.1 3.9 | 10.5 50.9 290 18 9 6.9 3.8
7750 10.7 51.3 295 18 9 8.7 4.8 | 11.1 52.0 285 17 9 10.1 5.5
7500 11.4 52.5 295 17 9 7.7 4.2 | 11.9 53.4 285 16 8 8.8 4.8
7250 11.9 53.4 290 17 9 6.1 3.4 | 12.4 54.3 280 14 7 6.2 3.4
7000 12.4 54.3 290 16 8 6.8 3.7 | 13.0 55.4 280 12 6 7.3 4.0
6750 12.9 55.2 285 15 8 7.0 3.8 | 13.6 56.5 275 11 5 11.1 6.1
6500 13.4 56.1 280 14 7 4.1 2.2 | 14.5 58.1 270 10 5 10.5 5.8
6250 13.6 56.5 275 12 6 2.9 1.6 | 15.2 59.4 270 9 5 8.0 4.4
6000 13.8 56.8 270 11 5 0.9 0.5 | 15.8 60.4 265 8 4 7.6 4.2
5750 13.2 55.8 250 8 4 -20.3 -11.2 | 16.4 61.5 255 5 3 11.0 6.1
5500 10.6 51.1 230 5 3 -46.9 -25.7 | 17.6 63.7 255 5 2 20.6 11.3
11/13/2025 AT 1400 MST | 11/13/2025 AT 1700 MST
|
CAPE... 0.0 LI... +3.1 | CAPE... 0.0 LI... +3.5
CINH... 0.0 K INDEX... +11.8 | CINH... 0.0 K INDEX... +14.0
|
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 -65.9 -86.6 280 43 22 3.9 2.1 | -65.8 -86.4 270 40 20 3.5 1.9
45000 -60.6 -77.1 280 59 30 2.1 1.2 | -60.7 -77.3 275 55 29 2.6 1.4
40000 -57.2 -71.0 275 75 39 4.6 2.5 | -56.7 -70.1 270 71 37 4.6 2.5
38000 -53.1 -63.6 275 74 38 6.9 3.8 | -52.7 -62.9 270 70 36 6.6 3.6
36000 -49.0 -56.2 270 72 37 6.9 3.8 | -48.8 -55.8 270 69 36 6.6 3.6
34000 -44.6 -48.3 270 69 36 7.7 4.2 | -44.4 -47.9 270 67 34 7.7 4.2
32000 -40.0 -40.0 270 65 33 7.7 4.2 | -39.8 -39.6 270 63 32 7.7 4.2
30000 -35.3 -31.5 270 62 32 7.8 4.3 | -35.2 -31.4 270 59 30 7.6 4.2
29000 -33.0 -27.4 270 61 32 7.8 4.3 | -32.4 -26.3 270 57 29 7.6 4.2
28000 -30.1 -22.2 270 60 31 7.9 4.3 | -30.1 -22.2 270 55 28 7.7 4.2
27000 -27.9 -18.2 270 59 30 7.2 4.0 | -28.0 -18.4 270 53 27 6.9 3.8
26000 -25.7 -14.3 275 56 29 7.2 4.0 | -26.0 -14.8 270 51 26 6.9 3.8
25000 -23.6 -10.5 275 54 28 7.2 3.9 | -23.9 -11.0 270 49 25 6.8 3.8
24000 -21.6 -6.9 275 50 26 6.3 3.5 | -21.9 -7.4 270 47 24 6.5 3.5
23000 -19.7 -3.5 270 45 23 6.3 3.5 | -20.0 -4.0 265 45 23 6.5 3.6
22000 -17.9 -0.2 265 39 20 6.4 3.5 | -18.1 -0.6 265 42 22 6.7 3.7
21000 -16.1 3.0 265 34 17 5.6 3.1 | -16.3 2.7 265 37 19 5.9 3.2
20000 -14.5 5.9 260 29 15 5.7 3.1 | -14.6 5.7 265 31 16 5.9 3.2
19500 -13.7 7.3 260 27 14 5.7 3.1 | -13.8 7.2 265 28 15 5.9 3.2
19000 -12.9 8.8 260 24 12 5.5 3.0 | -12.9 8.8 265 25 13 5.7 3.1
18500 -12.2 10.0 265 23 12 4.8 2.7 | -12.2 10.0 270 23 12 5.1 2.8
18000 -11.5 11.3 275 22 11 4.7 2.6 | -11.4 11.5 280 20 11 4.8 2.7
17500 -10.6 12.9 280 21 11 6.9 3.8 | -10.5 13.1 285 20 10 7.9 4.3
17000 -9.6 14.7 290 22 11 7.0 3.8 | -9.3 15.3 290 21 11 7.9 4.4
16500 -8.5 16.7 295 22 11 6.8 3.7 | -8.1 17.4 290 22 11 6.8 3.7
16000 -7.6 18.3 300 22 11 6.4 3.5 | -7.3 18.9 295 21 11 5.3 2.9
15500 -6.6 20.1 305 22 12 6.5 3.5 | -6.1 21.0 295 21 11 6.8 3.8
15000 -5.0 23.0 305 22 11 7.4 4.1 | -5.0 23.0 295 22 11 7.5 4.1
14500 -3.9 25.0 310 22 11 7.5 4.1 | -3.9 25.0 295 23 12 7.3 4.0
14000 -2.8 27.0 310 22 11 7.5 4.1 | -2.8 27.0 295 24 12 6.7 3.7
13500 -1.6 29.1 310 22 11 7.6 4.2 | -1.8 28.8 295 24 13 6.8 3.7
13000 -0.5 31.1 305 23 12 7.8 4.3 | -0.8 30.6 290 25 13 6.9 3.8
12500 0.7 33.3 305 23 12 7.8 4.3 | 0.2 32.4 290 26 14 7.0 3.8
12000 1.8 35.2 300 23 12 7.6 4.2 | 1.4 34.5 290 27 14 8.0 4.4
11500 2.9 37.2 300 22 12 7.6 4.2 | 2.5 36.5 285 26 13 7.9 4.4
11000 4.0 39.2 295 22 11 7.6 4.2 | 3.8 38.8 285 25 13 8.8 4.8
10500 5.1 41.2 290 21 11 6.6 3.6 | 5.0 41.0 280 24 12 7.3 4.0
10250 5.5 41.9 290 21 11 4.5 2.5 | 5.5 41.9 280 23 12 4.9 2.7
10000 5.9 42.6 290 21 11 7.6 4.2 | 5.9 42.6 280 22 12 9.0 5.0
9750 6.6 43.9 285 21 11 10.1 5.6 | 6.8 44.2 280 22 11 12.2 6.7
9500 7.3 45.1 285 20 10 9.2 5.1 | 7.6 45.7 280 21 11 10.7 5.9
9250 7.9 46.2 285 19 10 8.0 4.4 | 8.3 46.9 280 20 10 7.6 4.1
9000 8.5 47.3 280 18 9 8.7 4.8 | 8.8 47.8 280 19 10 8.4 4.6
8750 9.2 48.6 280 16 8 10.0 5.5 | 9.6 49.3 280 18 9 11.0 6.0
8500 9.9 49.8 275 14 7 9.5 5.2 | 10.4 50.7 280 17 9 10.0 5.5
8250 10.6 51.1 275 13 7 9.3 5.1 | 11.1 52.0 280 16 8 9.8 5.4
8000 11.3 52.3 275 12 6 9.3 5.1 | 11.8 53.2 280 16 8 9.3 5.1
7750 12.0 53.6 275 11 6 9.4 5.2 | 12.5 54.5 280 15 8 8.2 4.5
7500 12.7 54.9 275 11 6 9.6 5.3 | 13.1 55.6 280 14 7 8.7 4.8
7250 13.4 56.1 270 11 6 9.9 5.4 | 13.8 56.8 280 13 7 9.6 5.3
7000 14.2 57.6 270 10 5 9.7 5.3 | 14.5 58.1 280 12 6 9.3 5.1
6750 14.9 58.8 270 10 5 9.9 5.4 | 15.1 59.2 280 11 6 8.7 4.8
6500 15.6 60.1 270 10 5 10.2 5.6 | 15.8 60.4 280 11 5 8.8 4.8
6250 16.4 61.5 270 10 5 10.7 5.9 | 16.4 61.5 275 10 5 8.9 4.9
6000 17.2 63.0 270 9 5 9.4 5.2 | 17.1 62.8 275 9 4 10.0 5.5
5750 17.9 64.2 270 9 5 11.2 6.2 | 17.8 64.0 275 8 4 4.7 2.6
5500 19.0 66.2 270 9 4 18.1 10.0 | 17.6 63.7 270 6 3 -7.5 -4.1
________________________________________________________________________________
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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