501
UXUS97 KBOU 101342
SRGBOU
SOARING FORECAST
NATIONAL WEATHER SERVICE DENVER/BOULDER, COLORADO
0741 MDT THURSDAY, JULY 10, 2025
THIS FORECAST IS FOR THURSDAY, JULY 10, 2025:
IF THE TRIGGER TEMPERATURE OF 88.3 F/31.3 C IS REACHED...THEN
THERMAL SOARING INDEX....................... EXCELLENT
MAXIMUM RATE OF LIFT........................ 1029 FT/MIN (5.2 M/S)
MAXIMUM HEIGHT OF THERMALS.................. 19731 FT MSL (14390 FT AGL)
FORECAST MAXIMUM TEMPERATURE................... 94.0 F/34.9 C
TIME OF TRIGGER TEMPERATURE.................... 1030 MDT
TIME OF OVERDEVELOPMENT........................ NONE
MIDDLE/HIGH CLOUDS DURING SOARING WINDOW....... BROKEN/OVERCAST OPAQUE MIDDLE
SURFACE WINDS DURING SOARING WINDOW............ 20 MPH OR LESS
HEIGHT OF THE -3 THERMAL INDEX................. 10327 FT MSL (4986 FT AGL)
THERMAL SOARING OUTLOOK FOR FRIDAY 07/11....... 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 PVA
POTENTIAL HEIGHT OF WAVE....................... 40721 FT MSL (35380 FT AGL)
WAVE SOARING OUTLOOK FOR FRIDAY 07/11.......... POOR
REMARKS...
SUNRISE/SUNSET.................... 05:40:52 / 20:29:03 MDT
TOTAL POSSIBLE SUNSHINE........... 14 HR 48 MIN 11 SEC (888 MIN 11 SEC)
ALTITUDE OF SUN AT 13:04:58 MDT... 72.32 DEGREES
UPPER AIR DATA FROM NUMERICAL MODEL FORECAST VALID ON 07/10/2025 AT 0600 MDT
FREEZING LEVEL.................. 16419 FT MSL (11078 FT AGL)
CONVECTIVE CONDENSATION LEVEL... 18898 FT MSL (13557 FT AGL)
LIFTED CONDENSATION LEVEL....... 19182 FT MSL (13841 FT AGL)
LIFTED INDEX.................... -1.2
K INDEX......................... +22.7
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 -62.1 -79.8 260 29 15 1.9 1.0 M M M M M
45000 -58.0 -72.4 270 50 26 4.2 2.3 M M M M M
40000 -51.5 -60.7 270 65 33 5.4 3.0 M M M M M
38000 -48.2 -54.8 270 62 32 5.4 3.0 M M M M M
36000 -45.0 -49.0 270 58 30 5.2 2.9 M M M M M
34000 -40.8 -41.4 270 52 27 7.1 3.9 M M M M M
32000 -36.5 -33.7 265 45 23 7.0 3.8 M M M M M
30000 -31.3 -24.3 260 40 21 8.0 4.4 43.5 110.3 6.9 M M
29000 -28.9 -20.0 260 38 20 8.0 4.4 42.9 109.2 6.4 M M
28000 -26.6 -15.9 260 36 19 8.0 4.4 42.3 108.2 6.0 M M
27000 -24.2 -11.6 260 34 17 8.0 4.4 41.6 106.8 5.5 M M
26000 -21.8 -7.2 260 31 16 8.0 4.4 40.9 105.7 5.0 M M
25000 -19.5 -3.1 260 29 15 7.7 4.2 40.4 104.7 4.6 M M
24000 -17.4 0.7 265 27 14 7.0 3.8 39.3 102.8 3.7 M M
23000 -15.4 4.3 265 25 13 7.0 3.8 38.3 101.0 2.9 M M
22000 -13.3 8.1 265 23 12 7.0 3.8 37.4 99.4 2.1 M M
21000 -11.3 11.7 270 22 11 7.0 3.8 36.4 97.4 1.2 M M
20000 -9.2 15.4 270 21 11 7.0 3.8 35.4 95.7 0.3 M M
19500 -8.2 17.2 270 20 10 6.9 3.8 35.0 94.9 -0.1 1416 7.2
19000 -7.1 19.2 275 20 10 8.6 4.7 34.6 94.3 -0.4 1367 6.9
18500 -5.8 21.6 275 20 10 8.5 4.7 34.4 93.9 -0.6 1315 6.7
18000 -4.6 23.7 275 19 10 8.7 4.8 34.2 93.6 -0.9 1263 6.4
17500 -2.6 27.3 275 19 10 9.0 4.9 34.0 93.2 -1.1 1181 6.0
17000 -1.3 29.7 275 19 10 9.0 4.9 33.9 93.0 -1.2 1127 5.7
16500 0.1 32.2 275 18 9 9.0 4.9 33.7 92.7 -1.3 1072 5.4
16000 1.4 34.5 280 18 9 9.0 4.9 33.6 92.5 -1.5 1017 5.2
15500 2.7 36.9 280 18 9 9.0 5.0 33.5 92.3 -1.6 962 4.9
15000 4.1 39.4 280 18 9 9.0 5.0 33.4 92.1 -1.7 907 4.6
14500 5.4 41.7 280 18 9 9.0 5.0 33.3 91.9 -1.8 852 4.3
14000 6.8 44.2 280 18 9 9.0 5.0 33.1 91.7 -1.9 797 4.0
13500 8.1 46.6 280 18 9 9.3 5.1 33.0 91.5 -2.0 742 3.8
13000 9.5 49.1 280 18 9 9.5 5.2 33.0 91.4 -2.1 685 3.5
12500 10.9 51.6 280 18 9 9.3 5.1 33.0 91.3 -2.1 627 3.2
12000 12.3 54.1 280 18 9 9.1 5.0 32.9 91.1 -2.3 572 2.9
11500 13.7 56.7 280 18 9 9.0 5.0 32.8 91.0 -2.4 517 2.6
11000 15.0 59.0 280 17 9 8.6 4.7 32.6 90.7 -2.5 462 2.3
10500 16.3 61.3 280 17 9 5.2 2.9 32.5 90.5 -2.7 408 2.1
10250 16.6 61.9 280 16 8 6.4 3.5 32.0 89.6 -3.1 393 2.0
10000 17.4 63.3 280 16 8 11.8 6.5 32.1 89.7 -3.1 362 1.8
9750 18.1 64.6 280 15 8 10.7 5.8 32.1 89.9 -3.0 330 1.7
9500 18.9 66.0 280 15 8 9.8 5.4 32.2 90.0 -3.0 299 1.5
9250 19.6 67.3 280 14 7 8.0 4.4 32.1 89.8 -3.1 273 1.4
9000 20.2 68.4 280 13 7 8.9 4.9 32.0 89.6 -3.2 247 1.3
8750 20.9 69.6 280 13 7 9.7 5.3 32.0 89.6 -3.2 218 1.1
8500 21.6 70.9 280 12 6 8.9 4.9 32.0 89.6 -3.2 190 1.0
8250 22.2 72.0 280 12 6 7.1 3.9 31.9 89.3 -3.4 164 0.8
8000 22.7 72.9 285 10 5 7.8 4.3 31.6 89.0 -3.6 141 0.7
7750 23.4 74.1 285 10 5 9.4 5.1 31.6 88.8 -3.7 114 0.6
7500 24.0 75.2 285 10 5 7.8 4.3 31.5 88.7 -3.7 87 0.4
7250 24.5 76.1 285 10 5 6.1 3.3 31.3 88.3 -4.0 65 0.3
7000 25.0 77.0 290 9 5 6.2 3.4 31.0 87.8 -4.3 44 0.2
6750 25.5 77.9 290 8 4 7.7 4.2 30.8 87.4 -4.5 21 0.1
6500 26.0 78.8 290 8 4 5.0 2.7 30.6 87.0 -4.7 M M
6250 26.2 79.2 290 7 4 1.5 0.8 30.0 86.1 -5.3 M M
6000 26.4 79.5 285 6 3 4.0 2.2 29.5 85.1 -5.8 M M
5750 26.6 79.9 280 5 3 -0.6 -0.3 29.0 84.2 -6.4 M M
5500 25.9 78.6 270 5 2 -19.8 -10.8 27.6 81.6 -7.8 M M
* * * * * * NUMERICAL WEATHER PREDICTION MODEL FORECAST DATA VALID * * * * * *
07/10/2025 AT 0900 MDT | 07/10/2025 AT 1200 MDT
|
CAPE... +143.5 LI... 0.0 | CAPE... +365.9 LI... -1.0
CINH... -148.0 K INDEX... +23.6 | CINH... -53.6 K INDEX... +27.2
|
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 -60.6 -77.1 265 33 17 2.3 1.3 | -60.4 -76.7 275 33 17 3.1 1.7
45000 -57.1 -70.8 270 51 26 2.1 1.2 | -56.4 -69.5 275 50 26 1.4 0.8
40000 -53.1 -63.6 275 54 28 6.3 3.5 | -53.4 -64.1 275 52 27 6.8 3.7
38000 -49.3 -56.7 275 51 26 6.4 3.5 | -49.2 -56.6 275 51 26 7.0 3.8
36000 -45.5 -49.9 275 49 25 6.3 3.5 | -45.1 -49.2 275 50 26 7.0 3.8
34000 -41.1 -42.0 275 45 23 7.4 4.0 | -41.0 -41.8 270 46 24 6.8 3.7
32000 -36.7 -34.1 270 41 21 7.3 4.0 | -36.4 -33.5 265 41 21 7.0 3.8
30000 -31.8 -25.2 265 39 20 7.2 4.0 | -31.9 -25.4 265 39 20 7.6 4.2
29000 -29.7 -21.5 260 39 20 7.2 4.0 | -29.7 -21.5 265 38 19 7.6 4.2
28000 -27.5 -17.5 260 38 20 7.5 4.1 | -27.4 -17.3 265 37 19 7.6 4.2
27000 -25.3 -13.5 260 36 19 7.5 4.1 | -25.1 -13.2 260 36 18 7.7 4.2
26000 -23.1 -9.6 255 35 18 7.6 4.2 | -22.9 -9.2 260 35 18 7.7 4.2
25000 -20.8 -5.4 255 33 17 7.7 4.2 | -20.6 -5.1 260 35 18 7.6 4.2
24000 -18.6 -1.5 260 32 17 7.8 4.3 | -18.5 -1.3 260 34 18 7.3 4.0
23000 -16.3 2.7 260 32 16 7.8 4.3 | -16.3 2.7 265 34 18 7.3 4.0
22000 -14.0 6.8 265 31 16 8.0 4.4 | -14.2 6.4 265 34 18 7.5 4.1
21000 -11.6 11.1 265 30 15 8.2 4.5 | -11.9 10.6 265 33 17 7.9 4.3
20000 -9.2 15.4 265 28 14 8.2 4.5 | -9.6 14.7 270 32 17 7.9 4.4
19500 -8.0 17.6 265 27 14 8.2 4.5 | -8.5 16.7 270 32 16 7.9 4.4
19000 -6.8 19.8 265 26 13 8.6 4.7 | -7.3 18.9 270 31 16 8.2 4.5
18500 -5.5 22.1 265 25 13 8.6 4.7 | -6.1 21.0 270 29 15 8.2 4.5
18000 -4.3 24.3 265 24 12 8.6 4.7 | -4.3 24.3 270 28 14 8.4 4.6
17500 -3.0 26.6 265 23 12 8.6 4.7 | -3.1 26.4 270 26 13 8.4 4.6
17000 -1.7 28.9 265 22 11 8.6 4.7 | -1.9 28.6 270 25 13 8.6 4.7
16500 -0.4 31.3 265 21 11 8.6 4.7 | -0.6 30.9 270 23 12 8.9 4.9
16000 1.5 34.7 265 19 10 8.7 4.8 | 0.8 33.4 265 22 11 8.8 4.9
15500 2.8 37.0 265 18 9 8.9 4.9 | 2.1 35.8 265 20 11 9.5 5.2
15000 4.1 39.4 265 17 9 8.9 4.9 | 3.5 38.3 270 19 10 9.4 5.2
14500 5.4 41.7 265 17 9 8.7 4.8 | 4.9 40.8 270 18 9 9.4 5.1
14000 6.7 44.1 270 16 8 8.7 4.8 | 6.3 43.3 270 17 9 9.4 5.1
13500 8.0 46.4 270 16 8 8.9 4.9 | 7.7 45.9 270 16 8 9.3 5.1
13000 9.3 48.7 270 15 8 8.9 4.9 | 9.0 48.2 270 15 8 9.2 5.0
12500 10.6 51.1 275 15 8 8.8 4.8 | 10.4 50.7 275 15 8 9.1 5.0
12000 11.9 53.4 275 15 7 8.7 4.8 | 11.8 53.2 275 14 7 9.0 5.0
11500 13.2 55.8 275 14 7 8.8 4.8 | 13.1 55.6 280 13 7 8.8 4.8
11000 14.5 58.1 280 14 7 8.6 4.7 | 14.3 57.7 285 13 7 7.9 4.3
10500 15.9 60.6 280 14 7 4.4 2.4 | 15.4 59.7 290 13 7 11.9 6.5
10250 16.0 60.8 280 13 7 5.6 3.0 | 16.5 61.7 290 12 6 13.0 7.1
10000 16.8 62.2 280 14 7 11.9 6.5 | 17.2 63.0 290 12 6 8.3 4.5
9750 17.6 63.7 280 14 7 10.8 5.9 | 17.9 64.2 295 12 6 9.8 5.4
9500 18.4 65.1 285 14 7 8.8 4.8 | 18.6 65.5 295 12 6 8.5 4.6
9250 18.9 66.0 285 14 7 6.6 3.6 | 19.2 66.6 300 13 6 7.9 4.4
9000 19.5 67.1 285 13 7 9.0 4.9 | 19.8 67.6 300 13 7 9.3 5.1
8750 20.2 68.4 285 13 7 10.3 5.6 | 20.5 68.9 305 13 6 10.0 5.5
8500 20.9 69.6 285 13 7 8.7 4.8 | 21.3 70.3 305 13 6 9.5 5.2
8250 21.5 70.7 285 13 7 6.3 3.5 | 21.9 71.4 305 13 7 8.3 4.6
8000 21.9 71.4 290 13 7 7.6 4.2 | 22.6 72.7 310 14 7 9.0 5.0
7750 22.6 72.7 290 12 6 9.9 5.4 | 23.3 73.9 310 13 7 10.5 5.8
7500 23.3 73.9 290 12 6 7.2 3.9 | 24.1 75.4 310 13 7 9.1 5.0
7250 23.7 74.7 290 12 6 4.5 2.5 | 24.6 76.3 310 13 7 7.0 3.8
7000 24.0 75.2 290 12 6 6.0 3.3 | 25.1 77.2 310 14 7 7.8 4.3
6750 24.6 76.3 285 12 6 8.4 4.6 | 25.8 78.4 310 14 7 11.1 6.1
6500 25.2 77.4 285 11 6 7.2 3.9 | 26.7 80.1 310 14 7 10.2 5.6
6250 25.6 78.1 280 10 5 5.6 3.1 | 27.3 81.1 305 13 7 8.4 4.6
6000 26.0 78.8 280 8 4 5.4 3.0 | 27.9 82.2 305 12 6 8.2 4.5
5750 26.4 79.5 275 7 4 10.4 5.7 | 28.5 83.3 305 11 5 11.3 6.2
5500 27.6 81.7 270 6 3 21.3 11.7 | 29.8 85.6 305 9 5 23.9 13.1
07/10/2025 AT 1500 MDT | 07/10/2025 AT 1800 MDT
|
CAPE... +322.7 LI... -1.1 | CAPE... +346.2 LI... -1.2
CINH... -30.3 K INDEX... +21.9 | CINH... -36.1 K INDEX... +23.9
|
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 -61.0 -77.8 280 34 18 2.9 1.6 | -60.9 -77.6 285 30 15 2.4 1.3
45000 -57.1 -70.8 275 49 25 1.6 0.9 | -57.2 -71.0 280 44 23 2.4 1.3
40000 -53.8 -64.8 270 46 23 7.3 4.0 | -52.7 -62.9 280 41 21 6.6 3.6
38000 -49.3 -56.7 270 45 23 7.5 4.1 | -48.7 -55.7 280 40 20 6.7 3.7
36000 -44.8 -48.6 270 45 23 7.5 4.1 | -44.7 -48.5 280 38 20 6.7 3.7
34000 -40.6 -41.1 270 43 22 7.0 3.8 | -40.5 -40.9 280 38 19 6.9 3.8
32000 -36.4 -33.5 265 41 21 6.9 3.8 | -36.4 -33.5 285 37 19 6.9 3.8
30000 -31.5 -24.7 265 39 20 7.5 4.1 | -31.9 -25.4 280 37 19 7.6 4.2
29000 -29.2 -20.6 265 39 20 7.5 4.1 | -29.1 -20.4 280 36 19 7.6 4.2
28000 -27.0 -16.6 260 38 20 7.6 4.2 | -26.9 -16.4 275 35 18 7.2 4.0
27000 -24.7 -12.5 260 37 19 7.6 4.2 | -24.8 -12.6 275 35 18 7.2 3.9
26000 -22.5 -8.5 260 37 19 7.6 4.2 | -22.6 -8.7 270 34 18 7.2 4.0
25000 -20.3 -4.5 260 36 18 7.6 4.2 | -20.5 -4.9 270 33 17 7.3 4.0
24000 -18.1 -0.6 260 35 18 7.4 4.1 | -18.3 -0.9 270 32 17 7.5 4.1
23000 -15.9 3.4 260 34 17 7.4 4.1 | -16.1 3.0 265 31 16 7.6 4.1
22000 -13.7 7.3 265 33 17 7.4 4.1 | -13.9 7.0 265 29 15 7.6 4.2
21000 -11.6 11.1 265 31 16 7.3 4.0 | -11.7 10.9 265 29 15 7.6 4.2
20000 -9.4 15.1 270 29 15 7.3 4.0 | -9.5 14.9 270 29 15 7.6 4.2
19500 -8.4 16.9 270 28 14 7.2 4.0 | -8.4 16.9 270 29 15 7.6 4.2
19000 -7.2 19.0 270 27 14 8.6 4.7 | -7.2 19.0 270 28 15 8.1 4.4
18500 -6.0 21.2 275 26 14 8.6 4.7 | -6.0 21.2 275 28 14 8.1 4.4
18000 -4.7 23.5 275 25 13 8.5 4.7 | -4.8 23.4 275 27 14 8.4 4.6
17500 -3.5 25.7 275 24 13 8.5 4.7 | -3.6 25.5 280 26 13 8.7 4.8
17000 -2.2 28.0 280 23 12 8.5 4.6 | -2.3 27.9 280 25 13 8.7 4.8
16500 -0.2 31.6 280 22 11 9.2 5.0 | -1.0 30.2 285 24 12 9.0 4.9
16000 1.2 34.2 285 21 11 9.2 5.0 | 0.4 32.7 285 23 12 8.9 4.9
15500 2.6 36.7 285 20 10 9.5 5.2 | 1.7 35.1 290 22 11 9.0 5.0
15000 4.0 39.2 285 19 10 9.5 5.2 | 3.0 37.4 295 21 11 9.1 5.0
14500 5.4 41.7 285 18 9 9.3 5.1 | 5.0 41.0 300 19 10 8.9 4.9
14000 6.7 44.1 290 18 9 9.3 5.1 | 6.3 43.3 300 18 9 8.9 4.9
13500 8.1 46.6 290 17 9 9.3 5.1 | 7.7 45.9 305 17 9 8.8 4.9
13000 9.5 49.1 295 16 8 9.4 5.2 | 9.0 48.2 310 16 8 8.9 4.9
12500 10.9 51.6 295 16 8 9.4 5.1 | 10.3 50.5 315 15 8 8.9 4.9
12000 12.3 54.1 300 15 8 9.3 5.1 | 11.6 52.9 320 14 7 8.9 4.9
11500 13.7 56.7 300 15 8 9.0 5.0 | 12.9 55.2 330 13 7 8.9 4.9
11000 14.9 58.8 305 14 7 7.8 4.3 | 14.2 57.6 335 13 7 8.6 4.7
10500 16.0 60.8 300 14 7 11.2 6.2 | 15.5 59.9 340 12 6 3.7 2.0
10250 17.0 62.6 305 14 7 12.0 6.6 | 15.6 60.1 340 13 7 5.1 2.8
10000 17.6 63.7 305 13 7 7.9 4.4 | 16.4 61.5 345 13 7 12.8 7.0
9750 18.3 64.9 305 12 6 9.3 5.1 | 17.3 63.1 345 12 6 11.4 6.3
9500 18.9 66.0 305 12 6 8.0 4.4 | 18.1 64.6 350 12 6 9.2 5.1
9250 19.5 67.1 305 11 6 7.8 4.3 | 18.6 65.5 350 13 7 6.7 3.7
9000 20.1 68.2 300 10 5 9.4 5.2 | 19.2 66.6 355 13 7 9.6 5.3
8750 20.8 69.4 305 10 5 10.1 5.5 | 20.0 68.0 355 13 7 11.2 6.1
8500 21.5 70.7 305 9 5 9.6 5.2 | 20.8 69.4 360 12 6 9.6 5.3
8250 22.2 72.0 300 8 4 8.0 4.4 | 21.3 70.3 360 13 7 6.5 3.6
8000 22.7 72.9 300 7 4 8.7 4.8 | 21.8 71.2 360 14 7 8.7 4.8
7750 23.4 74.1 300 7 3 10.1 5.5 | 22.6 72.7 005 13 7 12.2 6.7
7500 24.2 75.6 305 6 3 9.3 5.1 | 23.5 74.3 010 12 6 9.3 5.1
7250 24.8 76.6 305 5 3 8.3 4.5 | 24.0 75.2 010 13 7 6.2 3.4
7000 25.4 77.7 305 5 2 8.9 4.9 | 24.5 76.1 010 14 7 8.2 4.5
6750 26.1 79.0 310 4 2 11.0 6.0 | 25.3 77.5 010 13 7 13.4 7.3
6500 27.0 80.6 320 3 2 10.9 6.0 | 26.3 79.3 015 12 6 11.4 6.2
6250 27.7 81.9 320 3 2 10.3 5.7 | 26.9 80.4 015 12 6 8.1 4.4
6000 28.5 83.3 325 3 1 9.9 5.4 | 27.6 81.7 010 13 6 8.7 4.8
5750 29.3 84.7 325 2 1 12.1 6.6 | 28.3 82.9 010 12 6 12.3 6.8
5500 30.5 86.9 335 2 1 23.3 12.8 | 29.5 85.1 015 10 5 20.3 11.1
________________________________________________________________________________
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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