670
UXUS97 KBOU 090112
SRGBOU
SOARING FORECAST
NATIONAL WEATHER SERVICE DENVER/BOULDER, COLORADO
1911 MDT TUESDAY, JULY 8, 2025
THIS FORECAST IS FOR WEDNESDAY, JULY 9, 2025:
IF THE TRIGGER TEMPERATURE OF 88.9 F/31.6 C IS REACHED...THEN
THERMAL SOARING INDEX....................... EXCELLENT
MAXIMUM RATE OF LIFT........................ 1845 FT/MIN (9.4 M/S)
MAXIMUM HEIGHT OF THERMALS.................. 23930 FT MSL (18638 FT AGL)
FORECAST MAXIMUM TEMPERATURE................... 101.0 F/38.8 C
TIME OF TRIGGER TEMPERATURE.................... 1030 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................. 20847 FT MSL (15555 FT AGL)
THERMAL SOARING OUTLOOK FOR THURSDAY 07/10..... EXCELLENT
WAVE SOARING INDEX............................. POOR
WAVE SOARING INDEX TREND (TO 1800 MDT)......... NO CHANGE
HEIGHT OF STABLE LAYER (12-18K FT MSL)......... NONE
WEAK PVA/NVA (THROUGH 1800 MDT)................ WEAK NVA
POTENTIAL HEIGHT OF WAVE....................... 40801 FT MSL (35509 FT AGL)
WAVE SOARING OUTLOOK FOR THURSDAY 07/10........ POOR
REMARKS...
SUNRISE/SUNSET.................... 05:40:12 / 20:29:28 MDT
TOTAL POSSIBLE SUNSHINE........... 14 HR 49 MIN 16 SEC (889 MIN 16 SEC)
ALTITUDE OF SUN AT 13:04:50 MDT... 72.45 DEGREES
UPPER AIR DATA FROM NUMERICAL MODEL FORECAST VALID ON 07/09/2025 AT 0600 MDT
FREEZING LEVEL.................. 16425 FT MSL (11133 FT AGL)
CONVECTIVE CONDENSATION LEVEL... 20688 FT MSL (15396 FT AGL)
LIFTED CONDENSATION LEVEL....... 22232 FT MSL (16940 FT AGL)
LIFTED INDEX.................... -1.9
K INDEX......................... +10.9
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 -64.2 -83.6 300 24 13 1.7 0.9 M M M M M
45000 -59.5 -75.1 305 40 21 5.5 3.0 M M M M M
40000 -50.9 -59.6 305 49 25 6.9 3.8 M M M M M
38000 -46.8 -52.2 305 50 26 6.9 3.8 M M M M M
36000 -42.7 -44.9 310 52 27 7.0 3.9 M M M M M
34000 -37.5 -35.5 305 50 26 7.7 4.2 M M M M M
32000 -32.9 -27.2 305 49 25 7.5 4.1 M M M M M
30000 -28.6 -19.5 310 46 24 7.0 3.8 47.3 117.1 6.8 M M
29000 -26.5 -15.7 310 45 23 7.0 3.8 46.3 115.3 6.1 M M
28000 -24.6 -12.3 315 43 22 4.8 2.6 45.1 113.1 5.3 M M
27000 -23.1 -9.6 315 37 19 5.0 2.8 43.2 109.7 3.8 M M
26000 -21.6 -6.9 315 31 16 5.0 2.8 41.4 106.5 2.4 M M
25000 -20.1 -4.2 315 26 13 5.9 3.2 39.8 103.6 1.2 M M
24000 -18.1 -0.6 320 25 13 6.6 3.6 38.5 101.3 0.1 M M
23000 -16.1 3.0 320 24 13 6.6 3.6 37.3 99.2 -0.9 1766 9.0
22000 -14.2 6.4 325 24 12 6.8 3.7 36.3 97.3 -1.8 1677 8.5
21000 -12.2 10.0 320 22 12 7.0 3.9 35.2 95.4 -2.8 1587 8.1
20000 -10.1 13.8 315 21 11 7.4 4.0 34.3 93.7 -3.7 1497 7.6
19500 -9.1 15.6 315 21 11 8.1 4.4 33.9 93.1 -4.1 1452 7.4
19000 -7.8 18.0 315 19 10 9.6 5.3 33.8 92.9 -4.3 1396 7.1
18500 -6.3 20.7 310 18 9 9.6 5.3 33.8 92.9 -4.3 1339 6.8
18000 -4.9 23.2 310 17 9 9.6 5.2 33.8 92.8 -4.4 1281 6.5
17500 -3.5 25.7 310 15 8 9.5 5.2 33.8 92.8 -4.5 1223 6.2
17000 -1.3 29.7 310 13 7 9.6 5.3 33.7 92.7 -4.5 1137 5.8
16500 0.1 32.2 315 12 6 9.6 5.2 33.7 92.6 -4.6 1079 5.5
16000 1.5 34.7 315 11 6 9.4 5.2 33.7 92.6 -4.6 1021 5.2
15500 2.9 37.2 320 10 5 9.3 5.1 33.6 92.4 -4.7 964 4.9
15000 4.3 39.7 320 9 5 9.3 5.1 33.5 92.3 -4.8 908 4.6
14500 5.7 42.3 320 9 4 9.3 5.1 33.4 92.2 -4.9 851 4.3
14000 7.1 44.8 320 8 4 9.3 5.1 33.4 92.0 -5.0 794 4.0
13500 8.5 47.3 320 7 4 9.2 5.1 33.3 91.9 -5.1 738 3.7
13000 9.9 49.8 320 6 3 9.3 5.1 33.2 91.8 -5.2 681 3.5
12500 11.3 52.3 320 6 3 8.9 4.9 33.1 91.6 -5.3 625 3.2
12000 12.6 54.7 320 5 3 8.9 4.9 33.0 91.3 -5.5 571 2.9
11500 13.9 57.0 320 5 3 9.1 5.0 32.8 91.1 -5.6 516 2.6
11000 15.3 59.5 315 5 3 9.3 5.1 32.7 90.9 -5.8 460 2.3
10500 16.5 61.7 315 5 3 4.0 2.2 32.5 90.4 -6.0 409 2.1
10250 16.8 62.2 315 5 3 7.4 4.1 32.0 89.6 -6.5 392 2.0
10000 17.7 63.9 310 5 3 12.9 7.1 32.1 89.9 -6.4 359 1.8
9750 18.5 65.3 310 5 3 10.9 6.0 32.3 90.1 -6.3 326 1.7
9500 19.3 66.7 305 6 3 8.1 4.5 32.3 90.2 -6.3 297 1.5
9250 19.8 67.6 305 6 3 7.0 3.8 32.1 89.8 -6.5 274 1.4
9000 20.4 68.7 305 6 3 9.9 5.5 32.0 89.6 -6.6 247 1.3
8750 21.2 70.2 300 6 3 10.1 5.6 32.1 89.7 -6.6 217 1.1
8500 21.9 71.4 300 6 3 8.1 4.4 32.0 89.6 -6.7 190 1.0
8250 22.4 72.3 300 6 3 6.9 3.8 31.8 89.3 -6.9 165 0.8
8000 23.0 73.4 300 6 3 8.9 4.9 31.6 89.0 -7.1 141 0.7
7750 23.7 74.7 300 7 3 9.8 5.4 31.7 89.0 -7.1 112 0.6
7500 24.3 75.7 300 7 4 8.1 4.5 31.6 88.8 -7.2 86 0.4
7250 24.9 76.8 300 7 4 7.3 4.0 31.4 88.6 -7.4 61 0.3
7000 25.5 77.9 300 8 4 9.8 5.4 31.3 88.3 -7.5 36 0.2
6750 26.2 79.2 300 8 4 6.3 3.4 31.3 88.3 -7.6 8 0.0
6500 26.3 79.3 300 8 4 0.1 0.1 30.7 87.2 -8.2 M M
6250 26.4 79.5 300 8 4 5.1 2.8 30.1 86.2 -8.9 M M
6000 26.6 79.9 300 8 4 -8.7 -4.7 29.5 85.1 -9.5 M M
5750 24.7 76.5 285 7 4 -37.9 -20.8 26.9 80.5 -12.1 24 0.1
5500 21.2 70.2 250 5 3 -46.3 -25.4 22.8 73.1 -16.4 122 0.6
* * * * * * NUMERICAL WEATHER PREDICTION MODEL FORECAST DATA VALID * * * * * *
07/09/2025 AT 0900 MDT | 07/09/2025 AT 1200 MDT
|
CAPE... +0.7 LI... +0.8 | CAPE... +1.7 LI... +0.5
CINH... -13.3 K INDEX... +9.1 | CINH... -7.6 K INDEX... +11.8
|
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 -63.8 -82.8 300 25 13 2.4 1.3 | -63.8 -82.8 295 25 13 2.1 1.2
45000 -58.9 -74.0 300 42 21 5.0 2.7 | -58.9 -74.0 300 41 21 5.3 2.9
40000 -51.1 -60.0 305 49 25 6.4 3.5 | -50.8 -59.4 305 47 24 6.2 3.4
38000 -47.2 -53.0 305 50 26 6.3 3.5 | -47.1 -52.8 305 47 24 6.2 3.4
36000 -42.9 -45.2 305 50 26 7.4 4.1 | -42.9 -45.2 305 47 24 7.1 3.9
34000 -38.3 -36.9 305 48 25 7.7 4.2 | -38.4 -37.1 300 45 23 7.4 4.1
32000 -33.6 -28.5 305 45 23 7.3 4.0 | -34.0 -29.2 300 44 22 7.3 4.0
30000 -29.7 -21.5 310 42 22 6.5 3.6 | -30.0 -22.0 305 39 20 6.6 3.6
29000 -27.7 -17.9 315 40 21 6.5 3.6 | -28.0 -18.4 310 37 19 6.6 3.6
28000 -25.8 -14.4 315 38 20 6.5 3.6 | -26.0 -14.8 310 35 18 6.7 3.7
27000 -23.8 -10.8 315 34 18 6.5 3.6 | -24.0 -11.2 310 32 17 6.7 3.7
26000 -21.9 -7.4 315 30 15 6.5 3.6 | -22.0 -7.6 310 29 15 6.7 3.7
25000 -19.9 -3.8 315 26 13 6.2 3.4 | -20.0 -4.0 310 26 14 6.3 3.5
24000 -18.1 -0.6 315 23 12 5.9 3.3 | -18.1 -0.6 305 24 13 6.2 3.4
23000 -16.4 2.5 315 21 11 6.0 3.3 | -16.3 2.7 305 22 12 6.2 3.4
22000 -14.6 5.7 315 19 10 7.5 4.1 | -14.4 6.1 300 21 11 8.0 4.4
21000 -12.2 10.0 315 18 9 8.0 4.4 | -11.9 10.6 300 19 10 8.4 4.6
20000 -9.9 14.2 315 17 9 8.1 4.4 | -8.8 16.2 300 17 9 8.5 4.6
19500 -8.1 17.4 315 16 8 8.9 4.9 | -7.5 18.5 300 16 8 8.3 4.5
19000 -6.8 19.8 315 16 8 8.9 4.9 | -6.3 20.7 300 15 8 8.3 4.6
18500 -5.5 22.1 310 15 8 9.1 5.0 | -5.1 22.8 300 14 7 8.5 4.7
18000 -4.1 24.6 310 14 7 9.3 5.1 | -3.8 25.2 300 14 7 9.0 4.9
17500 -2.7 27.1 310 14 7 9.3 5.1 | -2.5 27.5 300 14 7 9.0 4.9
17000 -1.3 29.7 310 13 7 9.4 5.2 | -1.1 30.0 300 13 7 9.5 5.2
16500 0.1 32.2 305 12 6 9.4 5.2 | 0.3 32.5 305 13 7 9.5 5.2
16000 1.5 34.7 305 11 6 9.4 5.2 | 1.7 35.1 305 13 7 9.5 5.2
15500 2.9 37.2 305 11 5 9.4 5.1 | 3.1 37.6 305 12 6 9.5 5.2
15000 4.3 39.7 305 10 5 9.4 5.1 | 4.5 40.1 305 12 6 9.5 5.2
14500 5.7 42.3 305 9 5 9.5 5.2 | 5.9 42.6 305 12 6 9.7 5.3
14000 7.2 45.0 305 8 4 9.5 5.2 | 7.4 45.3 305 11 6 9.7 5.3
13500 8.6 47.5 305 8 4 9.4 5.1 | 8.8 47.8 305 11 5 9.6 5.3
13000 10.0 50.0 305 7 4 9.4 5.2 | 10.2 50.4 305 10 5 9.6 5.3
12500 11.4 52.5 300 7 4 9.2 5.1 | 11.7 53.1 305 10 5 9.7 5.3
12000 12.8 55.0 300 7 3 9.2 5.1 | 13.1 55.6 305 9 5 9.8 5.4
11500 14.1 57.4 300 6 3 9.3 5.1 | 14.6 58.3 305 9 4 9.4 5.2
11000 15.5 59.9 295 6 3 9.5 5.2 | 16.0 60.8 305 8 4 9.7 5.3
10500 16.7 62.1 290 6 3 2.9 1.6 | 17.1 62.8 305 7 4 4.2 2.3
10250 16.9 62.4 290 6 3 7.3 4.0 | 17.5 63.5 305 7 4 8.7 4.8
10000 17.8 64.0 290 6 3 13.6 7.5 | 18.5 65.3 305 7 3 13.6 7.4
9750 18.7 65.7 290 6 3 11.4 6.2 | 19.4 66.9 305 6 3 11.8 6.5
9500 19.5 67.1 290 6 3 8.0 4.4 | 20.2 68.4 300 6 3 9.1 5.0
9250 20.0 68.0 285 6 3 6.9 3.8 | 20.8 69.4 305 6 3 8.6 4.7
9000 20.6 69.1 285 6 3 10.5 5.8 | 21.5 70.7 300 5 3 11.2 6.2
8750 21.4 70.5 285 7 3 10.7 5.9 | 22.4 72.3 300 5 3 11.1 6.1
8500 22.1 71.8 285 7 4 8.3 4.6 | 23.2 73.8 300 5 3 9.9 5.4
8250 22.7 72.9 285 7 4 7.1 3.9 | 23.9 75.0 300 5 3 9.1 5.0
8000 23.3 73.9 285 7 4 8.9 4.9 | 24.6 76.3 300 5 2 10.6 5.8
7750 24.0 75.2 285 8 4 9.1 5.0 | 25.4 77.7 300 5 3 10.7 5.9
7500 24.6 76.3 285 8 4 7.2 4.0 | 26.1 79.0 300 5 2 9.1 5.0
7250 25.1 77.2 285 8 4 5.9 3.2 | 26.8 80.2 300 5 2 8.2 4.5
7000 25.6 78.1 290 8 4 10.1 5.6 | 27.5 81.5 300 4 2 11.2 6.1
6750 26.4 79.5 290 9 4 8.0 4.4 | 28.4 83.1 300 5 2 12.4 6.8
6500 26.6 79.9 285 8 4 1.9 1.1 | 29.2 84.6 295 4 2 10.2 5.6
6250 26.8 80.2 285 7 4 3.6 2.0 | 30.0 86.0 295 4 2 10.4 5.7
6000 27.0 80.6 280 6 3 2.4 1.3 | 30.8 87.4 295 4 2 10.9 6.0
5750 27.2 81.0 275 5 2 6.7 3.6 | 31.8 89.2 300 4 2 18.3 10.0
5500 28.0 82.4 265 4 2 15.7 8.6 | 33.6 92.5 300 4 2 28.4 15.6
07/09/2025 AT 1500 MDT | 07/09/2025 AT 1800 MDT
|
CAPE... 0.0 LI... +1.5 | CAPE... +18.3 LI... +0.9
CINH... 0.0 K INDEX... +16.0 | CINH... -47.6 K INDEX... +16.5
|
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 -64.0 -83.2 285 21 11 2.4 1.3 | -63.9 -83.0 275 24 13 1.8 1.0
45000 -58.8 -73.8 295 35 18 5.4 3.0 | -59.1 -74.4 285 36 18 5.6 3.1
40000 -50.0 -58.0 300 47 24 6.5 3.6 | -50.5 -58.9 295 46 24 6.5 3.6
38000 -46.1 -51.0 300 47 24 6.5 3.6 | -46.6 -51.9 295 47 24 6.5 3.5
36000 -42.2 -44.0 300 48 24 6.9 3.8 | -42.2 -44.0 300 48 25 7.0 3.8
34000 -37.9 -36.2 295 45 23 7.2 3.9 | -37.9 -36.2 295 46 23 7.1 3.9
32000 -33.6 -28.5 295 43 22 7.3 4.0 | -33.7 -28.7 295 43 22 7.2 3.9
30000 -29.8 -21.6 295 39 20 6.3 3.4 | -29.8 -21.6 295 38 20 6.4 3.5
29000 -27.5 -17.5 300 36 19 6.3 3.5 | -27.9 -18.2 290 35 18 6.4 3.5
28000 -25.5 -13.9 300 34 18 7.1 3.9 | -26.0 -14.8 290 33 17 6.4 3.5
27000 -23.4 -10.1 300 32 17 7.1 3.9 | -24.0 -11.2 290 30 16 6.4 3.5
26000 -21.2 -6.2 300 30 16 7.1 3.9 | -22.1 -7.8 285 28 14 6.4 3.5
25000 -19.1 -2.4 300 28 15 6.9 3.8 | -20.1 -4.2 285 25 13 7.6 4.2
24000 -17.1 1.2 295 27 14 6.9 3.8 | -17.7 0.1 280 25 13 8.2 4.5
23000 -15.0 5.0 295 26 14 6.9 3.8 | -15.3 4.5 280 25 13 8.4 4.6
22000 -12.9 8.8 290 25 13 8.4 4.6 | -12.9 8.8 275 24 13 8.4 4.6
21000 -10.4 13.3 285 24 13 8.4 4.6 | -10.4 13.3 275 23 12 8.4 4.6
20000 -7.9 17.8 285 23 12 8.5 4.7 | -7.9 17.8 280 21 11 8.4 4.6
19500 -6.7 19.9 280 23 12 8.4 4.6 | -6.7 19.9 280 20 10 8.6 4.7
19000 -5.5 22.1 285 22 11 8.3 4.6 | -5.4 22.3 280 19 10 8.9 4.9
18500 -4.3 24.3 285 22 11 8.3 4.5 | -4.1 24.6 280 18 9 8.9 4.9
18000 -3.1 26.4 285 21 11 9.2 5.1 | -2.0 28.4 280 16 8 9.3 5.1
17500 -1.7 28.9 285 20 10 9.2 5.0 | -0.7 30.7 280 14 7 9.3 5.1
17000 -0.4 31.3 285 19 10 9.2 5.1 | 0.7 33.3 280 13 7 9.4 5.2
16500 1.0 33.8 290 17 9 9.3 5.1 | 2.1 35.8 280 12 6 9.4 5.2
16000 2.3 36.1 290 16 8 9.4 5.1 | 3.6 38.5 280 10 5 9.2 5.1
15500 3.6 38.5 290 14 7 8.9 4.9 | 4.9 40.8 280 8 4 8.9 4.9
15000 5.7 42.3 295 11 6 9.0 5.0 | 6.3 43.3 275 6 3 8.9 4.9
14500 7.0 44.6 300 9 5 9.2 5.0 | 7.6 45.7 275 5 2 9.0 4.9
14000 8.4 47.1 305 7 4 9.2 5.1 | 8.9 48.0 265 3 2 8.9 4.9
13500 9.7 49.5 305 6 3 8.5 4.7 | 10.3 50.5 255 2 1 9.1 5.0
13000 11.0 51.8 310 5 3 8.5 4.7 | 11.7 53.1 245 2 1 9.1 5.0
12500 12.3 54.1 315 4 2 8.9 4.9 | 13.0 55.4 235 1 1 9.1 5.0
12000 13.6 56.5 320 3 2 8.9 4.9 | 14.4 57.9 225 1 0 9.1 5.0
11500 15.0 59.0 325 3 1 9.1 5.0 | 15.7 60.3 200 1 0 9.0 4.9
11000 16.3 61.3 325 3 1 9.5 5.2 | 17.1 62.8 000 0 0 8.9 4.9
10500 17.4 63.3 325 2 1 4.8 2.6 | 18.3 64.9 000 0 0 5.6 3.1
10250 17.9 64.2 325 2 1 9.4 5.2 | 18.7 65.7 000 0 0 7.9 4.3
10000 18.8 65.8 325 2 1 13.3 7.3 | 19.5 67.1 325 1 0 11.9 6.5
9750 19.7 67.5 325 2 1 11.8 6.5 | 20.4 68.7 325 1 0 11.2 6.2
9500 20.5 68.9 325 2 1 8.6 4.7 | 21.2 70.2 325 1 0 8.9 4.9
9250 21.1 70.0 325 2 1 8.4 4.6 | 21.8 71.2 320 1 0 8.4 4.6
9000 21.9 71.4 320 3 1 11.5 6.3 | 22.5 72.5 320 1 1 11.3 6.2
8750 22.7 72.9 320 3 1 11.2 6.1 | 23.3 73.9 320 1 1 11.5 6.3
8500 23.5 74.3 320 3 1 9.8 5.4 | 24.2 75.6 320 1 1 10.1 5.6
8250 24.2 75.6 320 3 1 9.0 5.0 | 24.9 76.8 315 1 1 9.1 5.0
8000 24.9 76.8 320 3 1 10.4 5.7 | 25.6 78.1 315 2 1 9.7 5.3
7750 25.8 78.4 320 3 1 11.1 6.1 | 26.3 79.3 315 2 1 10.0 5.5
7500 26.5 79.7 315 3 1 10.2 5.6 | 27.1 80.8 315 2 1 10.0 5.5
7250 27.3 81.1 315 3 1 10.4 5.7 | 27.8 82.0 310 2 1 10.1 5.5
7000 28.1 82.6 315 3 1 9.6 5.2 | 28.6 83.5 310 2 1 10.0 5.5
6750 28.8 83.8 315 3 1 9.8 5.4 | 29.3 84.7 310 2 1 9.9 5.4
6500 29.5 85.1 315 3 1 10.9 6.0 | 30.1 86.2 310 2 1 9.9 5.4
6250 30.3 86.5 310 3 1 11.0 6.1 | 30.8 87.4 310 2 1 10.2 5.6
6000 31.1 88.0 310 3 1 10.3 5.6 | 31.6 88.9 310 2 1 9.3 5.1
5750 32.1 89.8 310 3 1 16.8 9.2 | 32.3 90.1 305 3 1 12.8 7.0
5500 33.8 92.8 310 3 1 29.7 16.3 | 33.6 92.5 310 3 1 21.3 11.7
________________________________________________________________________________
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
CLICK HERE TO GO TO PREVIOUS BULLETINS.
Main Text Page