710
UXUS97 KBOU 100033
SRGBOU
SOARING FORECAST
NATIONAL WEATHER SERVICE DENVER/BOULDER, COLORADO
1827 MDT WEDNESDAY, JULY 9, 2025
THIS FORECAST IS FOR THURSDAY, JULY 10, 2025:
IF THE TRIGGER TEMPERATURE OF 89.1 F/31.7 C IS REACHED...THEN
THERMAL SOARING INDEX....................... EXCELLENT
MAXIMUM RATE OF LIFT........................ 1283 FT/MIN (6.5 M/S)
MAXIMUM HEIGHT OF THERMALS.................. 18377 FT MSL (13077 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....... NONE
SURFACE WINDS DURING SOARING WINDOW............ 20 MPH OR LESS
HEIGHT OF THE -3 THERMAL INDEX................. 7844 FT MSL (2544 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....................... 40729 FT MSL (35429 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.................. 16589 FT MSL (11289 FT AGL)
CONVECTIVE CONDENSATION LEVEL... 18610 FT MSL (13310 FT AGL)
LIFTED CONDENSATION LEVEL....... 18606 FT MSL (13306 FT AGL)
LIFTED INDEX.................... -2.0
K INDEX......................... +24.0
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 -61.5 -78.7 250 23 12 1.4 0.8 M M M M M
45000 -58.0 -72.4 260 44 23 4.0 2.2 M M M M M
40000 -51.7 -61.1 275 65 34 5.5 3.0 M M M M M
38000 -48.4 -55.1 270 61 32 5.6 3.0 M M M M M
36000 -45.0 -49.0 270 57 30 5.4 2.9 M M M M M
34000 -40.9 -41.6 265 52 27 7.2 3.9 M M M M M
32000 -36.6 -33.9 265 46 24 7.1 3.9 M M M M M
30000 -31.5 -24.7 265 41 21 7.6 4.2 43.3 109.9 6.8 M M
29000 -29.2 -20.6 265 39 20 7.6 4.2 42.5 108.6 6.2 M M
28000 -26.9 -16.4 265 37 19 7.7 4.2 41.8 107.3 5.7 M M
27000 -24.6 -12.3 265 35 18 7.8 4.3 40.9 105.7 5.1 M M
26000 -22.3 -8.1 265 33 17 7.8 4.3 40.2 104.4 4.5 M M
25000 -20.0 -4.0 265 31 16 7.9 4.3 39.6 103.3 4.0 M M
24000 -17.7 0.1 265 29 15 8.0 4.4 38.9 101.9 3.4 M M
23000 -15.3 4.5 265 27 14 8.0 4.4 38.2 100.8 2.9 M M
22000 -12.9 8.8 260 26 13 7.8 4.3 37.7 99.8 2.5 M M
21000 -10.7 12.7 265 22 11 7.7 4.2 36.9 98.3 1.7 M M
20000 -8.4 16.9 265 19 10 7.8 4.3 36.2 97.1 1.1 M M
19500 -7.3 18.9 265 17 9 7.8 4.3 35.9 96.5 0.8 M M
19000 -6.2 20.8 265 16 8 7.9 4.3 35.5 96.0 0.5 M M
18500 -5.1 22.8 265 15 8 7.9 4.3 35.2 95.4 0.1 M M
18000 -3.9 25.0 265 15 8 8.4 4.6 34.9 94.8 -0.2 1255 6.4
17500 -2.6 27.3 260 14 7 8.7 4.8 34.7 94.5 -0.4 1202 6.1
17000 -1.4 29.5 260 14 7 8.7 4.8 34.5 94.2 -0.6 1149 5.8
16500 -0.1 31.8 265 13 7 8.8 4.8 34.4 93.9 -0.7 1096 5.6
16000 1.9 35.4 275 13 7 8.8 4.9 34.1 93.5 -0.9 1014 5.2
15500 3.2 37.8 275 13 7 9.1 5.0 34.0 93.2 -1.1 959 4.9
15000 4.6 40.3 280 13 7 9.1 5.0 33.9 93.0 -1.2 904 4.6
14500 5.9 42.6 285 13 7 9.2 5.1 33.8 92.8 -1.3 849 4.3
14000 7.3 45.1 290 14 7 9.2 5.1 33.7 92.7 -1.4 793 4.0
13500 8.7 47.7 290 14 7 9.4 5.1 33.6 92.6 -1.5 737 3.7
13000 10.1 50.2 290 15 8 9.4 5.2 33.6 92.5 -1.6 681 3.5
12500 11.4 52.5 295 16 8 9.2 5.1 33.5 92.4 -1.7 625 3.2
12000 12.8 55.0 295 17 9 9.1 5.0 33.4 92.1 -1.8 570 2.9
11500 14.1 57.4 295 18 9 9.2 5.0 33.3 92.0 -1.9 516 2.6
11000 15.5 59.9 295 19 10 9.2 5.0 33.3 91.9 -2.0 459 2.3
10500 16.9 62.4 295 20 10 4.7 2.6 33.2 91.8 -2.1 402 2.0
10250 17.0 62.6 295 20 10 5.2 2.9 32.6 90.7 -2.7 390 2.0
10000 17.8 64.0 295 20 10 11.7 6.4 32.7 90.8 -2.6 360 1.8
9750 18.6 65.5 295 20 10 10.3 5.6 32.7 90.9 -2.6 329 1.7
9500 19.4 66.9 295 20 10 9.5 5.2 32.8 91.0 -2.6 299 1.5
9250 20.0 68.0 295 19 10 8.2 4.5 32.7 90.8 -2.6 272 1.4
9000 20.6 69.1 300 19 10 9.1 5.0 32.6 90.7 -2.7 245 1.2
8750 21.3 70.3 300 19 10 9.4 5.2 32.6 90.6 -2.8 217 1.1
8500 22.0 71.6 300 19 10 9.2 5.1 32.5 90.5 -2.8 188 1.0
8250 22.7 72.9 300 19 10 9.3 5.1 32.5 90.5 -2.9 161 0.8
8000 23.4 74.1 295 20 10 8.7 4.8 32.4 90.4 -2.9 133 0.7
7750 24.0 75.2 295 21 11 8.4 4.6 32.3 90.2 -3.0 107 0.5
7500 24.6 76.3 295 22 11 7.8 4.3 32.2 90.0 -3.2 82 0.4
7250 25.2 77.4 290 23 12 7.0 3.8 32.0 89.7 -3.4 58 0.3
7000 25.7 78.3 285 23 12 7.3 4.0 31.8 89.3 -3.5 34 0.2
6750 26.3 79.3 285 24 12 7.4 4.0 31.7 89.0 -3.7 10 0.0
6500 26.7 80.1 285 24 12 0.7 0.4 31.3 88.3 -4.1 M M
6250 26.4 79.5 280 20 10 -4.9 -2.7 30.3 86.5 -5.1 M M
6000 26.1 79.0 275 17 9 -1.4 -0.8 29.3 84.8 -6.1 M M
5750 25.9 78.6 270 14 7 -7.0 -3.8 28.4 83.1 -7.0 M M
5500 24.7 76.5 255 9 5 -26.0 -14.3 26.5 79.6 -9.0 21 0.1
* * * * * * NUMERICAL WEATHER PREDICTION MODEL FORECAST DATA VALID * * * * * *
07/10/2025 AT 0900 MDT | 07/10/2025 AT 1200 MDT
|
CAPE... +148.0 LI... -0.4 | CAPE... +557.0 LI... -1.9
CINH... -106.4 K INDEX... +24.8 | CINH... -13.2 K INDEX... +29.9
|
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 -60.8 -77.4 270 28 15 2.5 1.4 | -60.7 -77.3 280 30 16 2.5 1.4
45000 -56.8 -70.2 275 47 24 2.6 1.4 | -56.8 -70.2 280 47 24 2.4 1.3
40000 -52.3 -62.1 285 54 28 5.8 3.2 | -52.6 -62.7 280 50 26 6.3 3.4
38000 -48.8 -55.8 280 52 27 5.9 3.2 | -48.8 -55.8 275 51 26 6.4 3.5
36000 -45.3 -49.5 275 51 26 5.8 3.2 | -44.9 -48.8 275 52 27 6.4 3.5
34000 -41.2 -42.2 275 48 25 7.0 3.8 | -40.9 -41.6 275 48 25 6.7 3.7
32000 -37.0 -34.6 270 44 23 6.9 3.8 | -36.9 -34.4 270 44 23 6.7 3.7
30000 -32.0 -25.6 270 38 20 7.7 4.2 | -31.9 -25.4 270 39 20 7.5 4.1
29000 -29.7 -21.5 270 35 18 7.7 4.2 | -29.7 -21.5 265 36 19 7.5 4.1
28000 -27.4 -17.3 270 32 17 7.2 4.0 | -27.5 -17.5 265 34 18 7.0 3.8
27000 -25.3 -13.5 270 31 16 7.2 4.8 | -25.4 -13.7 265 35 18 6.9 3.8
26000 -23.1 -9.6 270 30 15 7.2 4.0 | -23.3 -9.9 265 35 18 7.0 3.8
25000 -21.0 -5.8 270 29 15 7.3 4.0 | -21.3 -6.3 265 35 18 7.0 3.8
24000 -18.8 -1.8 270 29 15 7.6 4.2 | -19.2 -2.6 265 36 19 7.0 3.9
23000 -16.6 2.1 265 30 15 7.6 4.2 | -17.2 1.0 265 37 19 7.1 3.9
22000 -14.4 6.1 260 31 16 8.1 4.4 | -15.1 4.8 265 38 19 7.9 4.3
21000 -11.9 10.6 260 28 15 8.6 4.7 | -12.5 9.5 265 35 18 9.0 5.0
20000 -9.4 15.1 260 26 13 8.6 4.7 | -9.9 14.2 265 33 17 9.1 5.0
19500 -8.1 17.4 255 24 13 8.6 4.7 | -8.6 16.5 265 31 16 9.2 5.0
19000 -6.9 19.6 255 23 12 8.2 4.5 | -7.3 18.9 265 30 15 8.7 4.8
18500 -5.7 21.7 255 21 11 8.3 4.5 | -6.1 21.0 265 27 14 8.8 4.8
18000 -4.5 23.9 250 19 10 8.4 4.6 | -4.8 23.4 265 25 13 8.5 4.7
17500 -3.2 26.2 250 18 9 8.4 4.6 | -3.6 25.5 260 22 12 8.2 4.5
17000 -2.0 28.4 250 17 9 8.4 4.6 | -1.8 28.8 260 19 10 8.5 4.6
16500 -0.0 32.0 250 15 8 8.8 4.8 | -0.5 31.1 260 17 9 8.7 4.8
16000 1.3 34.3 250 15 7 8.8 4.8 | 0.7 33.3 260 15 8 8.7 4.8
15500 2.6 36.7 250 14 7 9.0 5.0 | 2.0 35.6 260 14 7 8.9 4.9
15000 3.9 39.0 250 13 7 9.1 5.0 | 3.4 38.1 260 13 7 8.9 4.9
14500 5.2 41.4 255 12 6 8.6 4.7 | 4.7 40.5 260 13 6 9.2 5.0
14000 6.5 43.7 260 12 6 8.6 4.7 | 6.1 43.0 260 12 6 9.2 5.1
13500 7.7 45.9 260 11 6 8.9 4.9 | 7.4 45.3 260 11 6 9.2 5.1
13000 9.1 48.4 265 10 5 9.1 5.0 | 8.8 47.8 265 10 5 9.2 5.1
12500 10.4 50.7 270 10 5 9.2 5.0 | 10.2 50.4 265 10 5 9.2 5.0
12000 11.8 53.2 275 10 5 9.2 5.1 | 11.5 52.7 275 9 5 9.1 5.0
11500 13.1 55.6 280 11 6 9.0 4.9 | 12.9 55.2 285 10 5 8.9 4.9
11000 14.4 57.9 285 12 6 8.2 4.5 | 14.1 57.4 285 9 5 8.4 4.6
10500 15.6 60.1 285 13 6 4.5 2.5 | 15.4 59.7 290 8 4 5.2 2.8
10250 15.8 60.4 285 12 6 5.9 3.2 | 15.7 60.3 290 6 3 6.7 3.7
10000 16.6 61.9 290 12 6 11.8 6.5 | 16.5 61.7 295 6 3 12.0 6.6
9750 17.4 63.3 295 12 6 10.6 5.8 | 17.3 63.1 300 5 3 11.0 6.0
9500 18.2 64.8 295 12 6 9.4 5.2 | 18.1 64.6 305 5 3 9.6 5.3
9250 18.8 65.8 295 12 6 7.9 4.3 | 18.7 65.7 320 4 2 8.4 4.6
9000 19.5 67.1 295 12 6 9.4 5.2 | 19.4 66.9 325 4 2 10.4 5.7
8750 20.2 68.4 300 13 6 10.1 5.6 | 20.2 68.4 330 4 2 11.0 6.1
8500 20.9 69.6 300 13 7 9.3 5.1 | 21.0 69.8 330 4 2 10.3 5.7
8250 21.6 70.9 300 13 7 8.2 4.5 | 21.8 71.2 340 4 2 9.2 5.0
8000 22.2 72.0 300 13 7 8.6 4.7 | 22.5 72.5 350 4 2 9.8 5.4
7750 22.9 73.2 305 13 7 9.6 5.3 | 23.3 73.9 345 4 2 10.9 6.0
7500 23.5 74.3 305 14 7 7.9 4.3 | 24.0 75.2 345 4 2 9.8 5.4
7250 24.0 75.2 305 13 7 6.0 3.3 | 24.7 76.5 350 4 2 8.4 4.6
7000 24.5 76.1 305 13 7 7.5 4.1 | 25.4 77.7 355 4 2 9.6 5.3
6750 25.2 77.4 305 12 6 10.1 5.6 | 26.2 79.2 355 4 2 12.1 6.7
6500 26.0 78.8 305 11 6 8.7 4.8 | 27.1 80.8 350 4 2 11.7 6.4
6250 26.5 79.7 305 9 5 7.0 3.9 | 27.9 82.2 355 4 2 11.0 6.0
6000 27.0 80.6 305 7 4 6.6 3.6 | 28.7 83.7 360 4 2 9.9 5.4
5750 27.5 81.5 305 6 3 9.7 5.3 | 29.5 85.1 360 4 2 13.3 7.3
5500 28.6 83.5 305 5 3 19.6 10.8 | 30.9 87.6 360 4 2 27.2 14.9
07/10/2025 AT 1500 MDT | 07/10/2025 AT 1800 MDT
|
CAPE... +184.0 LI... -1.1 | CAPE... +817.9 LI... -3.4
CINH... -21.1 K INDEX... +32.2 | CINH... -66.3 K INDEX... +26.8
|
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 -61.5 -78.7 280 30 15 2.2 1.2 | -62.0 -79.6 290 28 14 2.1 1.2
45000 -58.2 -72.8 280 40 21 2.4 1.3 | -57.9 -72.2 285 35 18 3.5 1.9
40000 -53.6 -64.5 270 43 22 7.3 4.0 | -52.0 -61.6 280 32 16 6.8 3.7
38000 -49.2 -56.6 265 44 23 7.4 4.1 | -47.9 -54.2 280 30 16 6.8 3.8
36000 -44.8 -48.6 260 45 23 7.2 3.9 | -43.8 -46.8 285 29 15 6.8 3.7
34000 -38.9 -38.0 260 42 22 8.9 4.9 | -39.6 -39.3 280 29 15 7.0 3.8
32000 -33.6 -28.5 255 38 20 9.6 5.2 | -35.4 -31.7 275 29 15 7.0 3.8
30000 -28.8 -19.8 250 36 18 8.0 4.4 | -30.5 -22.9 270 28 15 7.5 4.1
29000 -26.4 -15.5 250 34 18 8.0 4.4 | -28.3 -18.9 265 28 15 7.6 4.1
28000 -24.1 -11.4 245 33 17 7.1 3.9 | -26.0 -14.8 260 28 15 7.4 4.1
27000 -22.1 -7.8 250 31 16 6.9 3.8 | -23.9 -11.0 265 29 15 7.4 4.0
26000 -20.0 -4.0 250 30 15 7.0 3.8 | -21.7 -7.1 265 29 15 7.4 4.0
25000 -18.0 -0.4 250 28 15 7.0 3.9 | -19.5 -3.1 265 30 15 7.4 4.1
24000 -15.8 3.6 250 27 14 7.4 4.1 | -17.3 0.9 265 33 17 7.4 4.1
23000 -13.7 7.3 250 25 13 7.5 4.1 | -15.1 4.8 265 36 19 7.4 4.1
22000 -11.5 11.3 255 24 12 7.3 4.0 | -12.9 8.8 265 40 21 7.3 4.0
21000 -9.7 14.5 255 22 11 6.2 3.4 | -10.9 12.4 265 39 20 6.9 3.8
20000 -7.9 17.8 260 19 10 6.2 3.4 | -8.9 16.0 260 38 20 7.0 3.9
19500 -7.0 19.4 260 18 9 6.3 3.4 | -7.9 17.8 260 38 19 7.0 3.8
19000 -5.7 21.7 265 16 8 5.8 3.2 | -6.8 19.8 260 37 19 7.9 4.4
18500 -4.9 23.2 265 14 7 5.8 3.2 | -5.7 21.7 265 37 19 8.0 4.4
18000 -4.0 24.8 265 12 6 6.2 3.4 | -4.5 23.9 265 38 19 7.9 4.3
17500 -3.1 26.4 270 10 5 6.3 3.5 | -3.4 25.9 270 36 19 7.6 4.2
17000 -2.2 28.0 270 8 4 6.1 3.3 | -2.3 27.9 275 35 18 7.6 4.2
16500 -1.4 29.5 275 7 3 5.0 2.8 | -0.6 30.9 280 33 17 7.5 4.1
16000 -0.7 30.7 285 5 2 5.0 2.7 | 0.5 32.9 285 32 16 7.4 4.1
15500 0.1 32.2 300 3 2 6.4 3.5 | 1.6 34.9 290 31 16 8.0 4.4
15000 1.0 33.8 330 3 1 6.3 3.5 | 2.8 37.0 295 29 15 8.0 4.4
14500 2.0 35.6 360 3 2 7.7 4.2 | 3.9 39.0 300 28 15 7.3 4.0
14000 3.2 37.8 010 3 2 8.3 4.6 | 4.9 40.8 305 26 14 7.1 3.9
13500 4.4 39.9 020 4 2 8.5 4.7 | 5.9 42.6 310 25 13 7.1 3.9
13000 5.7 42.3 030 4 2 8.8 4.8 | 6.9 44.4 315 22 11 7.0 3.9
12500 7.0 44.6 035 5 2 8.9 4.9 | 7.9 46.2 320 20 10 7.0 3.8
12000 8.3 46.9 035 5 3 9.0 4.9 | 8.8 47.8 325 18 9 6.8 3.7
11500 9.7 49.5 035 5 3 8.9 4.9 | 9.8 49.6 335 16 8 6.7 3.7
11000 10.9 51.6 035 5 3 8.0 4.4 | 10.6 51.1 340 15 8 5.6 3.1
10500 12.1 53.8 035 5 3 7.0 3.8 | 11.5 52.7 350 14 7 4.5 2.4
10250 12.6 54.7 035 5 3 7.7 4.2 | 11.8 53.2 355 13 7 5.4 3.0
10000 13.3 55.9 035 5 3 9.7 5.3 | 12.3 54.1 360 13 7 7.7 4.2
9750 13.9 57.0 035 5 3 9.1 5.0 | 12.8 55.0 005 12 6 7.2 4.0
9500 14.6 58.3 035 5 3 9.6 5.3 | 13.3 55.9 010 12 6 6.9 3.8
9250 15.3 59.5 035 5 3 10.0 5.5 | 13.8 56.8 010 12 6 6.0 3.3
9000 16.0 60.8 030 5 3 9.0 4.9 | 14.2 57.6 015 11 6 7.2 3.9
8750 16.6 61.9 030 5 3 8.1 4.4 | 14.8 58.6 020 11 6 8.3 4.6
8500 17.2 63.0 025 5 2 9.0 4.9 | 15.3 59.5 025 10 5 7.7 4.2
8250 18.0 64.4 025 5 2 11.5 6.3 | 15.9 60.6 025 9 5 7.4 4.1
8000 18.9 66.0 020 5 2 10.5 5.8 | 16.4 61.5 035 9 4 7.0 3.9
7750 19.5 67.1 020 5 2 7.9 4.3 | 16.9 62.4 040 8 4 6.6 3.6
7500 20.2 68.4 020 4 2 9.8 5.4 | 17.3 63.1 045 7 4 7.0 3.8
7250 21.0 69.8 015 4 2 12.2 6.7 | 17.8 64.0 055 6 3 7.5 4.1
7000 21.9 71.4 015 4 2 11.4 6.3 | 18.3 64.9 070 6 3 7.4 4.1
6750 22.6 72.7 015 4 2 7.8 4.3 | 18.8 65.8 080 6 3 7.7 4.2
6500 23.2 73.8 015 4 2 10.0 5.5 | 19.4 66.9 085 7 3 9.8 5.4
6250 24.2 75.6 010 4 2 13.4 7.4 | 20.2 68.4 090 7 3 11.7 6.4
6000 25.1 77.2 010 3 2 12.1 6.6 | 21.0 69.8 090 7 3 9.8 5.4
5750 26.0 78.8 010 3 2 11.2 6.2 | 21.8 71.2 090 6 3 12.4 6.8
5500 26.8 80.2 015 3 2 12.9 7.1 | 23.1 73.6 090 6 3 22.5 12.4
________________________________________________________________________________
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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