688
UXUS97 KBOU 080126
SRGBOU
SOARING FORECAST
NATIONAL WEATHER SERVICE DENVER/BOULDER, COLORADO
1925 MDT THURSDAY, AUGUST 7, 2025
THIS FORECAST IS FOR FRIDAY, AUGUST 8, 2025:
IF THE TRIGGER TEMPERATURE OF 89.5 F/32.0 C IS REACHED...THEN
THERMAL SOARING INDEX....................... EXCELLENT
MAXIMUM RATE OF LIFT........................ 1281 FT/MIN (6.5 M/S)
MAXIMUM HEIGHT OF THERMALS.................. 19492 FT MSL (14206 FT AGL)
FORECAST MAXIMUM TEMPERATURE................... 97.0 F/36.6 C
TIME OF TRIGGER TEMPERATURE.................... 1100 MDT
TIME OF OVERDEVELOPMENT........................ 1600 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................. 14100 FT MSL (8814 FT AGL)
THERMAL SOARING OUTLOOK FOR SATURDAY 08/09..... GOOD
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)................ NEITHER
POTENTIAL HEIGHT OF WAVE....................... 19072 FT MSL (13786 FT AGL)
WAVE SOARING OUTLOOK FOR SATURDAY 08/09........ POOR
REMARKS...
SUNRISE/SUNSET.................... 06:05:35 / 20:04:34 MDT
TOTAL POSSIBLE SUNSHINE........... 13 HR 58 MIN 59 SEC (838 MIN 59 SEC)
ALTITUDE OF SUN AT 13:05:04 MDT... 66.10 DEGREES
UPPER AIR DATA FROM NUMERICAL MODEL FORECAST VALID ON 08/08/2025 AT 0600 MDT
FREEZING LEVEL.................. 16732 FT MSL (11446 FT AGL)
CONVECTIVE CONDENSATION LEVEL... 22620 FT MSL (17334 FT AGL)
LIFTED CONDENSATION LEVEL....... 21707 FT MSL (16421 FT AGL)
LIFTED INDEX.................... +1.5
K INDEX......................... +13.9
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 -64.8 -84.6 260 37 19 0.4 0.2 M M M M M
45000 -62.6 -80.7 255 54 28 4.0 2.2 M M M M M
40000 -55.9 -68.6 250 51 26 7.7 4.2 M M M M M
38000 -51.2 -60.2 250 47 24 7.8 4.3 M M M M M
36000 -46.5 -51.7 250 43 22 7.8 4.3 M M M M M
34000 -41.7 -43.1 250 41 21 8.1 4.4 M M M M M
32000 -36.9 -34.4 250 39 20 7.9 4.4 M M M M M
30000 -31.0 -23.8 255 37 19 8.8 4.8 43.8 110.9 5.8 M M
29000 -28.4 -19.1 255 36 18 8.8 4.8 43.5 110.3 5.7 M M
28000 -25.8 -14.4 255 35 18 8.3 4.5 43.2 109.7 5.5 M M
27000 -23.3 -9.9 255 34 17 8.3 4.6 42.5 108.5 5.0 M M
26000 -20.8 -5.4 260 33 17 8.3 4.6 42.0 107.6 4.7 M M
25000 -18.3 -0.9 260 32 16 7.8 4.3 41.6 106.9 4.4 M M
24000 -16.1 3.0 260 32 17 7.2 3.9 40.5 105.0 3.6 M M
23000 -14.0 6.8 265 33 17 7.2 3.9 39.6 103.3 2.8 M M
22000 -11.9 10.6 265 34 17 7.2 3.9 38.8 101.8 2.1 M M
21000 -9.8 14.4 265 36 19 7.2 4.0 37.8 100.0 1.2 M M
20000 -7.7 18.1 265 39 20 7.3 4.0 36.9 98.4 0.4 M M
19500 -6.6 20.1 265 40 20 7.3 4.0 36.5 97.7 0.1 M M
19000 -5.5 22.1 265 41 21 8.1 4.4 36.2 97.1 -0.3 1340 6.8
18500 -4.4 24.1 265 41 21 8.1 4.4 35.9 96.6 -0.6 1291 6.6
18000 -3.2 26.2 265 41 21 8.0 4.4 35.6 96.1 -0.9 1241 6.3
17500 -2.1 28.2 265 41 21 8.0 4.4 35.3 95.5 -1.2 1191 6.1
17000 -0.9 30.4 265 41 21 8.0 4.4 35.0 95.0 -1.5 1141 5.8
16500 0.3 32.5 265 40 21 8.2 4.5 34.7 94.5 -1.8 1091 5.5
16000 1.5 34.7 265 39 20 8.2 4.5 34.5 94.0 -2.1 1040 5.3
15500 3.3 37.9 265 37 19 8.1 4.5 34.1 93.3 -2.4 963 4.9
15000 4.6 40.3 265 36 18 8.1 4.4 33.8 92.8 -2.7 911 4.6
14500 5.8 42.4 265 34 17 8.8 4.8 33.6 92.4 -2.9 859 4.4
14000 7.1 44.8 265 31 16 8.7 4.8 33.4 92.1 -3.1 804 4.1
13500 8.5 47.3 265 28 15 9.1 5.0 33.3 91.9 -3.2 750 3.8
13000 9.9 49.8 265 26 13 9.2 5.1 33.2 91.7 -3.3 693 3.5
12500 11.3 52.3 265 24 12 9.2 5.0 33.1 91.6 -3.4 637 3.2
12000 12.6 54.7 260 22 11 9.2 5.0 33.0 91.4 -3.5 581 3.0
11500 14.0 57.2 260 20 10 9.3 5.1 32.9 91.3 -3.6 525 2.7
11000 15.4 59.7 260 19 10 9.2 5.1 32.9 91.2 -3.6 468 2.4
10500 16.8 62.2 255 18 9 5.6 3.1 32.8 91.1 -3.7 410 2.1
10250 17.1 62.8 255 18 9 6.8 3.7 32.4 90.3 -4.1 394 2.0
10000 18.0 64.4 255 18 9 12.3 6.7 32.5 90.5 -4.0 361 1.8
9750 18.8 65.8 255 18 9 11.5 6.3 32.6 90.7 -3.9 328 1.7
9500 19.7 67.5 255 18 9 8.9 4.9 32.7 90.9 -3.8 295 1.5
9250 20.2 68.4 255 17 9 6.6 3.6 32.5 90.5 -4.0 273 1.4
9000 20.8 69.4 255 17 9 9.8 5.4 32.4 90.3 -4.2 247 1.3
8750 21.6 70.9 255 17 9 11.2 6.1 32.4 90.4 -4.1 216 1.1
8500 22.4 72.3 255 17 9 9.2 5.1 32.5 90.5 -4.0 184 0.9
8250 23.0 73.4 255 18 9 6.4 3.5 32.3 90.2 -4.2 160 0.8
8000 23.5 74.3 255 18 9 8.4 4.6 32.1 89.8 -4.5 138 0.7
7750 24.2 75.6 255 19 10 11.1 6.1 32.1 89.9 -4.4 107 0.5
7500 25.0 77.0 255 19 10 8.4 4.6 32.2 89.9 -4.4 77 0.4
7250 25.5 77.9 255 20 10 6.1 3.3 31.9 89.5 -4.7 55 0.3
7000 26.0 78.8 255 20 10 7.4 4.1 31.7 89.1 -4.9 33 0.2
6750 26.5 79.7 250 20 10 7.8 4.3 31.6 88.8 -5.1 8 0.0
6500 26.9 80.4 250 20 10 -0.2 -0.1 31.2 88.2 -5.5 M M
6250 26.5 79.7 245 19 10 -6.3 -3.4 30.1 86.2 -6.6 M M
6000 26.1 79.0 245 17 9 -3.2 -1.8 29.0 84.2 -7.7 M M
5750 25.7 78.3 240 16 8 -12.3 -6.7 27.9 82.1 -8.9 4 0.0
5500 24.0 75.2 230 12 6 -31.5 -17.3 25.4 77.8 -11.4 48 0.2
* * * * * * NUMERICAL WEATHER PREDICTION MODEL FORECAST DATA VALID * * * * * *
08/08/2025 AT 0900 MDT | 08/08/2025 AT 1200 MDT
|
CAPE... 0.0 LI... +2.6 | CAPE... +0.2 LI... +1.0
CINH... 0.0 K INDEX... +13.6 | CINH... -0.3 K INDEX... +14.2
|
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 -83.2 265 35 18 -0.4 -0.2 | -63.8 -82.8 260 32 16 -0.2 -0.1
45000 -62.8 -81.0 260 56 29 3.7 2.0 | -62.5 -80.5 260 54 28 3.4 1.8
40000 -56.5 -69.7 255 54 28 8.1 4.4 | -56.8 -70.2 250 53 27 8.0 4.4
38000 -51.6 -60.9 250 50 26 8.2 4.5 | -51.9 -61.4 250 51 26 8.2 4.5
36000 -46.7 -52.1 250 45 23 8.2 4.5 | -46.9 -52.4 250 49 25 8.2 4.5
34000 -41.9 -43.4 250 42 22 7.9 4.3 | -41.9 -43.4 250 47 24 8.3 4.6
32000 -36.6 -33.9 245 39 20 8.5 4.7 | -36.3 -33.3 245 44 23 8.8 4.9
30000 -31.6 -24.9 245 36 19 8.4 4.6 | -31.4 -24.5 245 40 21 8.1 4.5
29000 -29.0 -20.2 245 35 18 8.4 4.6 | -29.0 -20.2 245 38 20 8.1 4.5
28000 -26.5 -15.7 245 33 17 8.1 4.4 | -26.6 -15.9 245 37 19 7.8 4.3
27000 -24.1 -11.4 250 32 17 8.1 4.5 | -24.3 -11.7 245 36 19 7.8 4.3
26000 -21.7 -7.1 250 32 16 8.1 4.5 | -21.9 -7.4 250 35 18 7.8 4.3
25000 -19.2 -2.6 255 31 16 7.9 4.4 | -19.6 -3.3 250 35 18 7.6 4.2
24000 -16.9 1.6 255 32 16 7.7 4.2 | -17.4 0.7 255 35 18 7.2 3.9
23000 -14.6 5.7 260 32 17 7.7 4.2 | -15.3 4.5 255 36 18 7.2 3.9
22000 -12.3 9.9 260 33 17 7.4 4.1 | -13.2 8.2 260 36 19 7.1 3.9
21000 -10.2 13.6 260 36 19 7.2 4.0 | -11.1 12.0 260 36 19 7.1 3.9
20000 -8.1 17.4 265 39 20 7.3 4.0 | -9.0 15.8 260 37 19 7.1 3.9
19500 -7.1 19.2 265 40 21 7.3 4.0 | -8.0 17.6 260 37 19 7.0 3.9
19000 -6.0 21.2 265 42 21 7.9 4.3 | -6.9 19.6 260 37 19 8.3 4.5
18500 -4.8 23.4 265 43 22 7.9 4.3 | -5.7 21.7 260 37 19 8.2 4.5
18000 -3.7 25.3 260 43 22 7.9 4.3 | -4.4 24.1 260 37 19 8.4 4.6
17500 -2.6 27.3 260 43 22 7.9 4.3 | -3.2 26.2 260 36 18 8.7 4.8
17000 -1.4 29.5 260 42 22 7.9 4.4 | -1.2 29.8 260 34 18 8.9 4.9
16500 0.4 32.7 260 40 21 8.6 4.7 | 0.1 32.2 260 33 17 9.0 4.9
16000 1.7 35.1 260 39 20 8.6 4.7 | 1.4 34.5 260 31 16 9.0 4.9
15500 3.0 37.4 260 37 19 8.9 4.9 | 2.8 37.0 260 29 15 9.2 5.1
15000 4.4 39.9 260 35 18 8.9 4.9 | 4.1 39.4 260 28 14 9.2 5.0
14500 5.7 42.3 260 33 17 8.7 4.8 | 5.5 41.9 255 26 13 9.2 5.0
14000 7.0 44.6 260 31 16 8.7 4.8 | 6.9 44.4 255 25 13 9.2 5.0
13500 8.3 46.9 260 28 14 8.6 4.7 | 8.2 46.8 255 23 12 9.4 5.1
13000 9.6 49.3 260 25 13 8.6 4.7 | 9.6 49.3 255 22 11 9.5 5.2
12500 10.8 51.4 255 23 12 8.8 4.8 | 11.1 52.0 255 20 10 9.4 5.2
12000 12.2 54.0 255 22 11 9.0 4.9 | 12.5 54.5 255 19 10 9.4 5.2
11500 13.5 56.3 255 21 11 9.1 5.0 | 13.9 57.0 255 18 9 9.4 5.2
11000 14.9 58.8 250 20 10 8.9 4.9 | 15.3 59.5 255 17 9 9.2 5.0
10500 16.3 61.3 250 18 9 5.2 2.9 | 16.7 62.1 255 16 8 5.7 3.1
10250 16.5 61.7 245 17 9 6.5 3.6 | 17.0 62.6 255 15 8 6.9 3.8
10000 17.4 63.3 245 17 9 12.2 6.7 | 17.8 64.0 255 15 8 12.3 6.7
9750 18.2 64.8 245 17 9 11.3 6.2 | 18.7 65.7 255 14 7 11.4 6.3
9500 19.0 66.2 245 18 9 9.3 5.1 | 19.5 67.1 255 14 7 9.5 5.2
9250 19.6 67.3 245 17 9 7.3 4.0 | 20.1 68.2 255 13 7 8.0 4.4
9000 20.2 68.4 240 17 9 9.6 5.3 | 20.8 69.4 255 13 7 10.4 5.7
8750 21.0 69.8 240 17 9 10.7 5.9 | 21.6 70.9 255 12 6 11.1 6.1
8500 21.7 71.1 240 17 9 9.2 5.0 | 22.4 72.3 255 12 6 9.9 5.5
8250 22.3 72.1 240 17 9 7.0 3.8 | 23.1 73.6 255 12 6 7.8 4.3
8000 22.9 73.2 245 17 9 8.4 4.6 | 23.7 74.7 255 11 6 9.7 5.3
7750 23.6 74.5 245 17 9 10.4 5.7 | 24.5 76.1 255 11 6 12.2 6.7
7500 24.3 75.7 245 17 9 8.0 4.4 | 25.4 77.7 255 11 6 9.8 5.4
7250 24.8 76.6 240 18 9 5.9 3.2 | 26.0 78.8 255 10 5 7.2 4.0
7000 25.3 77.5 240 18 9 7.3 4.0 | 26.6 79.9 255 10 5 9.2 5.1
6750 25.9 78.6 240 17 9 8.8 4.9 | 27.4 81.3 255 10 5 13.1 7.2
6500 26.4 79.5 240 16 8 4.8 2.6 | 28.4 83.1 255 9 5 11.5 6.3
6250 26.6 79.9 235 15 8 1.6 0.9 | 29.1 84.4 255 9 5 9.5 5.2
6000 26.7 80.1 235 14 7 2.1 1.2 | 29.8 85.6 255 8 4 9.3 5.1
5750 26.9 80.4 230 13 7 4.6 2.5 | 30.6 87.1 255 8 4 13.4 7.3
5500 27.5 81.5 225 10 5 10.9 6.0 | 32.0 89.6 255 7 4 25.0 13.7
08/08/2025 AT 1500 MDT | 08/08/2025 AT 1800 MDT
|
CAPE... +9.8 LI... -0.6 | CAPE... +8.0 LI... -0.2
CINH... -7.4 K INDEX... +14.8 | CINH... -24.0 K INDEX... +13.5
|
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 -63.7 -82.7 260 35 18 0.0 0.0 | -63.6 -82.5 265 35 18 -0.0 -0.0
45000 -62.3 -80.1 260 52 27 3.2 1.8 | -62.3 -80.1 265 50 26 3.2 1.7
40000 -56.7 -70.1 255 47 24 7.9 4.3 | -56.7 -70.1 265 46 24 8.4 4.6
38000 -51.9 -61.4 255 45 23 8.1 4.4 | -51.6 -60.9 265 44 23 8.6 4.7
36000 -47.0 -52.6 255 43 22 8.1 4.4 | -46.4 -51.5 260 42 22 8.6 4.7
34000 -42.0 -43.6 255 42 22 8.4 4.6 | -41.4 -42.5 255 41 21 8.3 4.6
32000 -37.0 -34.6 255 42 22 8.3 4.5 | -35.8 -32.4 255 41 21 8.9 4.9
30000 -31.3 -24.3 255 41 21 8.5 4.7 | -31.3 -24.3 255 41 21 7.4 4.1
29000 -28.7 -19.7 255 40 21 8.6 4.7 | -29.1 -20.4 260 40 21 7.4 4.1
28000 -26.2 -15.2 255 39 20 6.9 3.8 | -26.9 -16.4 260 40 21 6.9 3.8
27000 -24.2 -11.6 255 37 19 6.9 3.8 | -24.9 -12.8 255 38 20 6.9 3.8
26000 -22.2 -8.0 255 36 18 6.9 3.8 | -22.9 -9.2 255 37 19 6.9 3.8
25000 -20.2 -4.4 255 34 17 6.9 3.8 | -20.8 -5.4 255 35 18 7.3 4.0
24000 -18.1 -0.6 255 33 17 6.9 3.8 | -18.5 -1.3 250 33 17 8.0 4.4
23000 -16.1 3.0 255 33 17 7.0 3.8 | -16.2 2.8 245 31 16 8.1 4.4
22000 -14.0 6.8 255 32 17 7.6 4.1 | -13.8 7.2 240 30 15 8.3 4.6
21000 -11.6 11.1 255 31 16 8.1 4.5 | -11.3 11.7 240 27 14 8.5 4.7
20000 -9.2 15.4 255 29 15 8.2 4.5 | -8.8 16.2 240 24 12 8.5 4.7
19500 -8.0 17.6 255 28 15 8.2 4.5 | -7.5 18.5 240 23 12 8.6 4.7
19000 -6.7 19.9 255 27 14 9.8 5.4 | -6.2 20.8 240 22 11 9.2 5.1
18500 -5.3 22.5 255 26 14 9.7 5.3 | -4.8 23.4 245 22 11 9.2 5.0
18000 -3.8 25.2 255 25 13 9.6 5.3 | -3.4 25.9 245 21 11 9.3 5.1
17500 -2.4 27.7 255 25 13 9.6 5.3 | -2.0 28.4 250 21 11 9.5 5.2
17000 -0.9 30.4 255 24 12 9.6 5.3 | -0.5 31.1 250 21 11 9.5 5.2
16500 0.5 32.9 255 23 12 9.6 5.3 | 0.9 33.6 250 21 11 9.5 5.2
16000 1.9 35.4 255 23 12 9.6 5.3 | 3.0 37.4 255 21 11 9.5 5.2
15500 3.4 38.1 255 22 11 9.5 5.2 | 4.5 40.1 255 21 11 9.6 5.3
15000 5.5 41.9 255 20 11 9.5 5.2 | 5.9 42.6 260 20 10 9.6 5.3
14500 6.9 44.4 255 19 10 9.5 5.2 | 7.3 45.1 260 20 10 9.5 5.2
14000 8.4 47.1 255 18 9 9.5 5.2 | 8.8 47.8 260 20 10 9.5 5.2
13500 9.8 49.6 260 17 9 9.5 5.2 | 10.2 50.4 265 20 10 9.5 5.2
13000 11.2 52.2 260 16 8 9.5 5.2 | 11.6 52.9 265 20 10 9.6 5.2
12500 12.6 54.7 260 16 8 9.7 5.3 | 13.0 55.4 270 20 10 9.5 5.2
12000 14.1 57.4 260 15 8 9.9 5.5 | 14.5 58.1 270 19 10 9.5 5.2
11500 15.6 60.1 265 15 8 9.9 5.4 | 15.9 60.6 275 19 10 9.1 5.0
11000 17.1 62.8 265 15 8 9.5 5.2 | 17.1 62.8 275 19 10 8.5 4.7
10500 18.5 65.3 265 15 8 5.3 2.9 | 18.4 65.1 280 19 10 12.8 7.0
10250 18.8 65.8 265 15 8 6.4 3.5 | 19.6 67.3 280 19 10 13.6 7.5
10000 19.6 67.3 265 15 8 12.7 7.0 | 20.3 68.5 280 19 10 8.2 4.5
9750 20.5 68.9 265 16 8 11.7 6.4 | 21.0 69.8 280 19 10 10.2 5.6
9500 21.4 70.5 270 16 8 9.3 5.1 | 21.7 71.1 285 19 10 7.8 4.3
9250 21.9 71.4 270 16 8 8.1 4.4 | 22.2 72.0 285 19 10 8.1 4.4
9000 22.7 72.9 270 16 8 10.9 6.0 | 23.0 73.4 285 19 10 10.8 5.9
8750 23.5 74.3 270 16 8 11.4 6.3 | 23.8 74.8 285 19 10 11.2 6.1
8500 24.3 75.7 270 16 8 10.0 5.5 | 24.6 76.3 285 19 10 10.0 5.5
8250 25.0 77.0 270 16 8 7.2 4.0 | 25.2 77.4 285 19 10 7.4 4.0
8000 25.6 78.1 270 16 8 9.8 5.4 | 25.8 78.4 290 19 10 9.3 5.1
7750 26.5 79.7 270 16 8 12.9 7.1 | 26.6 79.9 290 19 10 11.8 6.5
7500 27.3 81.1 275 15 8 10.4 5.7 | 27.5 81.5 290 19 10 10.2 5.6
7250 28.0 82.4 275 15 8 7.9 4.3 | 28.2 82.8 290 18 9 8.6 4.7
7000 28.6 83.5 275 15 8 9.4 5.2 | 28.8 83.8 290 18 9 9.3 5.1
6750 29.5 85.1 275 15 8 12.6 6.9 | 29.6 85.3 290 18 9 11.7 6.4
6500 30.4 86.7 275 15 8 11.1 6.1 | 30.5 86.9 295 18 9 10.7 5.9
6250 31.1 88.0 275 14 7 9.2 5.0 | 31.2 88.2 295 17 9 9.1 5.0
6000 31.8 89.2 275 14 7 9.2 5.1 | 31.9 89.4 295 16 8 9.5 5.2
5750 32.6 90.7 275 14 7 13.6 7.5 | 32.6 90.7 295 16 8 10.9 6.0
5500 34.0 93.2 275 12 6 24.6 13.5 | 33.5 92.3 300 14 7 13.7 7.5
________________________________________________________________________________
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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