496
UXUS97 KBOU 180120
SRGBOU
SOARING FORECAST
NATIONAL WEATHER SERVICE DENVER/BOULDER, COLORADO
1919 MDT TUESDAY, MARCH 17, 2026
THIS FORECAST IS FOR WEDNESDAY, MARCH 18, 2026:
IF THE TRIGGER TEMPERATURE OF 67.9 F/20.0 C IS REACHED...THEN
THERMAL SOARING INDEX....................... EXCELLENT
MAXIMUM RATE OF LIFT........................ 880 FT/MIN (4.5 M/S)
MAXIMUM HEIGHT OF THERMALS.................. 16017 FT MSL (10592 FT AGL)
FORECAST MAXIMUM TEMPERATURE................... 80.0 F/27.1 C
TIME OF TRIGGER TEMPERATURE.................... 1115 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................. 12505 FT MSL (7080 FT AGL)
THERMAL SOARING OUTLOOK FOR THURSDAY 03/19..... 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....................... 40090 FT MSL (34665 FT AGL)
WAVE SOARING OUTLOOK FOR THURSDAY 03/19........ GOOD
REMARKS...
SUNRISE/SUNSET.................... 07:05:28 / 19:09:21 MDT
TOTAL POSSIBLE SUNSHINE........... 12 HR 3 MIN 53 SEC (723 MIN 53 SEC)
ALTITUDE OF SUN AT 13:07:25 MDT... 49.48 DEGREES
UPPER AIR DATA FROM NUMERICAL MODEL FORECAST VALID ON 03/18/2026 AT 0600 MDT
FREEZING LEVEL.................. 13516 FT MSL (8091 FT AGL)
CONVECTIVE CONDENSATION LEVEL... 23772 FT MSL (18347 FT AGL)
LIFTED CONDENSATION LEVEL....... 20512 FT MSL (15087 FT AGL)
LIFTED INDEX.................... +6.1
K INDEX......................... +4.7
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 -67.1 -88.8 330 57 29 3.3 1.8 81.6 178.8 31.9 M M
45000 -62.5 -80.5 330 66 34 1.9 1.1 66.4 151.5 24.7 M M
40000 -59.5 -75.1 335 75 39 3.6 2.0 48.4 119.1 14.4 M M
38000 -54.1 -65.4 330 76 39 8.4 4.6 46.4 115.4 13.5 M M
36000 -49.0 -56.2 325 76 39 8.4 4.6 45.4 113.8 13.2 M M
34000 -44.0 -47.2 320 73 37 8.4 4.6 44.2 111.6 12.6 M M
32000 -39.0 -38.2 325 67 34 8.4 4.6 43.2 109.7 12.2 M M
30000 -34.1 -29.4 325 62 32 8.0 4.4 41.9 107.4 11.5 M M
29000 -31.8 -25.2 325 59 30 8.0 4.4 41.2 106.2 11.1 M M
28000 -29.4 -20.9 325 57 29 8.0 4.4 40.6 105.1 10.8 M M
27000 -27.0 -16.6 325 56 29 7.7 4.2 39.9 103.7 10.3 M M
26000 -24.8 -12.6 325 55 28 7.7 4.2 39.0 102.2 9.7 M M
25000 -22.5 -8.5 330 54 28 7.7 4.2 38.3 100.9 9.2 M M
24000 -20.4 -4.7 325 54 28 6.1 3.3 37.3 99.2 8.5 M M
23000 -18.1 -0.6 325 53 27 6.1 3.4 35.6 96.1 7.2 M M
22000 -16.3 2.7 325 53 27 6.1 3.4 34.4 93.9 6.2 M M
21000 -14.4 6.1 325 51 26 6.6 3.6 33.2 91.7 5.3 M M
20000 -12.5 9.5 325 49 25 6.6 3.6 32.0 89.7 4.3 M M
19500 -11.5 11.3 325 48 25 6.6 3.6 31.5 88.7 3.9 M M
19000 -10.5 13.1 325 47 24 6.2 3.4 31.0 87.8 3.4 M M
18500 -9.7 14.5 325 46 24 6.1 3.3 30.3 86.6 2.9 M M
18000 -8.8 16.2 330 45 23 6.1 3.3 29.7 85.5 2.3 M M
17500 -7.9 17.8 330 44 23 5.9 3.2 29.1 84.3 1.7 M M
17000 -7.0 19.4 330 42 22 5.9 3.3 28.4 83.2 1.2 M M
16500 -6.2 20.8 330 41 21 5.9 3.2 27.8 82.0 0.6 M M
16000 -5.3 22.5 330 40 21 5.9 3.2 27.1 80.8 -0.0 878 4.5
15500 -4.4 24.1 330 39 20 6.2 3.4 26.5 79.7 -0.6 837 4.3
15000 -3.4 25.9 330 37 19 7.0 3.8 26.0 78.8 -1.1 792 4.0
14500 -2.4 27.7 335 35 18 7.0 3.8 25.5 78.0 -1.5 746 3.8
14000 -1.2 29.8 335 34 17 7.9 4.4 25.2 77.3 -1.8 698 3.5
13500 -0.1 31.8 335 32 16 8.0 4.4 24.9 76.7 -2.1 647 3.3
13000 1.1 34.0 335 30 15 6.5 3.5 24.5 76.0 -2.5 599 3.0
12500 2.0 35.6 335 28 14 6.5 3.6 23.9 75.1 -3.0 555 2.8
12000 3.0 37.4 335 26 13 6.2 3.4 23.4 74.1 -3.4 511 2.6
11500 4.0 39.2 330 25 13 6.2 3.4 22.8 73.1 -4.0 468 2.4
11000 4.9 40.8 325 25 13 5.9 3.2 22.2 72.0 -4.5 425 2.2
10500 5.8 42.4 320 26 13 5.7 3.1 21.6 70.9 -5.1 383 1.9
10250 6.2 43.2 320 27 14 6.6 3.6 21.3 70.4 -5.4 362 1.8
10000 6.8 44.2 315 27 14 6.6 3.6 21.1 70.0 -5.6 339 1.7
9750 7.2 45.0 310 28 14 5.6 3.1 20.8 69.4 -5.9 318 1.6
9500 7.7 45.9 310 28 14 5.9 3.3 20.5 68.9 -6.2 298 1.5
9250 8.1 46.6 310 28 15 5.7 3.1 20.2 68.4 -6.5 277 1.4
9000 8.5 47.3 305 28 15 5.9 3.2 19.9 67.8 -6.8 257 1.3
8750 9.0 48.2 305 28 14 6.3 3.4 19.6 67.3 -7.1 236 1.2
8500 9.5 49.1 300 27 14 6.2 3.4 19.3 66.8 -7.4 215 1.1
8250 10.4 50.7 300 26 13 6.6 3.6 18.8 65.8 -8.0 172 0.9
8000 10.9 51.6 300 25 13 7.4 4.1 18.6 65.4 -8.2 149 0.8
7750 11.5 52.7 295 23 12 7.6 4.2 18.4 65.1 -8.4 125 0.6
7500 12.0 53.6 295 22 11 6.6 3.6 18.2 64.8 -8.6 101 0.5
7250 12.4 54.3 295 20 10 5.7 3.1 17.9 64.3 -8.9 81 0.4
7000 12.9 55.2 290 19 10 6.8 3.7 17.7 63.8 -9.2 60 0.3
6750 13.3 55.9 290 16 8 3.6 2.0 17.4 63.3 -9.5 39 0.2
6500 13.3 55.9 280 13 7 -1.6 -0.9 16.7 62.0 -10.3 32 0.2
6250 13.2 55.8 270 11 6 -0.4 -0.2 15.8 60.5 -11.2 28 0.1
6000 13.0 55.4 255 9 4 -6.4 -3.5 15.0 58.9 -12.1 26 0.1
5750 11.8 53.2 230 8 4 -27.5 -15.1 13.0 55.4 -14.1 56 0.3
5500 9.2 48.6 210 6 3 -33.9 -18.6 9.7 49.5 -17.5 126 0.6
* * * * * * NUMERICAL WEATHER PREDICTION MODEL FORECAST DATA VALID * * * * * *
03/18/2026 AT 0900 MDT | 03/18/2026 AT 1200 MDT
|
CAPE... 0.0 LI... +7.3 | CAPE... 0.0 LI... +6.3
CINH... -0.0 K INDEX... +1.5 | CINH... -0.0 K INDEX... -15.6
|
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 -68.3 -90.9 325 52 27 2.3 1.3 | -68.6 -91.5 325 46 23 0.9 0.5
45000 -64.6 -84.3 330 59 30 3.5 1.9 | -66.2 -87.2 330 54 28 4.9 2.7
40000 -59.4 -74.9 335 64 33 5.8 3.2 | -58.2 -72.8 330 55 28 9.0 5.0
38000 -53.5 -64.3 330 65 33 8.8 4.8 | -53.0 -63.4 325 58 30 8.5 4.7
36000 -48.2 -54.8 330 66 34 8.8 4.8 | -47.9 -54.2 320 62 32 8.5 4.7
34000 -43.2 -45.8 330 66 34 8.1 4.4 | -43.2 -45.8 320 63 32 7.7 4.2
32000 -38.4 -37.1 330 67 34 8.1 4.4 | -38.5 -37.3 320 63 33 7.7 4.2
30000 -33.6 -28.5 330 67 35 7.8 4.3 | -33.9 -29.0 325 63 33 7.7 4.2
29000 -31.3 -24.3 330 67 35 7.8 4.3 | -31.6 -24.9 325 63 33 7.7 4.2
28000 -29.0 -20.2 330 68 35 7.8 4.3 | -29.3 -20.7 325 64 33 7.7 4.2
27000 -26.7 -16.1 330 66 34 7.4 4.0 | -27.0 -16.6 325 63 33 7.6 4.2
26000 -24.5 -12.1 330 64 33 7.4 4.1 | -24.7 -12.5 325 63 32 7.6 4.2
25000 -22.3 -8.1 330 62 32 7.4 4.0 | -22.5 -8.5 325 63 32 7.6 4.2
24000 -19.7 -3.5 325 60 31 6.8 3.7 | -19.7 -3.5 325 62 32 7.1 3.9
23000 -17.6 0.3 325 59 30 6.8 3.7 | -17.6 0.3 325 61 32 7.1 3.9
22000 -15.6 3.9 325 58 30 6.8 3.8 | -15.4 4.3 320 61 31 7.1 3.9
21000 -13.6 7.5 325 56 29 6.5 3.6 | -13.5 7.7 320 60 31 6.2 3.4
20000 -11.7 10.9 325 54 28 6.5 3.6 | -11.7 10.9 325 59 30 6.2 3.4
19500 -10.8 12.6 325 53 28 6.5 3.6 | -10.8 12.6 325 58 30 6.2 3.4
19000 -9.8 14.4 325 52 27 5.9 3.2 | -9.8 14.4 325 58 30 6.4 3.5
18500 -9.0 15.8 325 51 26 5.8 3.2 | -8.9 16.0 325 56 29 6.5 3.5
18000 -8.2 17.2 325 50 25 5.8 3.2 | -7.9 17.8 325 54 28 6.5 3.5
17500 -7.4 18.7 330 48 25 5.6 3.1 | -6.9 19.6 330 52 27 6.5 3.5
17000 -6.6 20.1 330 46 24 5.7 3.1 | -6.0 21.2 330 50 26 6.4 3.5
16500 -5.8 21.6 330 45 23 5.8 3.2 | -5.0 23.0 330 48 25 6.7 3.7
16000 -4.9 23.2 330 43 22 5.8 3.2 | -4.0 24.8 330 46 24 6.8 3.7
15500 -4.1 24.6 330 41 21 6.3 3.5 | -3.0 26.6 335 43 22 7.0 3.9
15000 -3.0 26.6 335 40 21 7.1 3.9 | -1.9 28.6 335 41 21 7.3 4.0
14500 -2.0 28.4 335 39 20 7.2 3.9 | -0.8 30.6 335 38 19 7.3 4.0
14000 -0.8 30.6 335 37 19 8.4 4.6 | 0.3 32.5 335 35 18 7.5 4.1
13500 0.5 32.9 340 36 19 8.5 4.6 | 1.4 34.5 335 32 16 7.5 4.1
13000 1.7 35.1 340 35 18 7.0 3.8 | 2.5 36.5 335 29 15 7.3 4.0
12500 2.8 37.0 335 33 17 7.3 4.0 | 3.6 38.5 335 27 14 7.4 4.0
12000 3.8 38.8 335 31 16 5.9 3.3 | 4.7 40.5 330 25 13 6.8 3.7
11500 4.7 40.5 330 29 15 6.0 3.3 | 5.7 42.3 330 23 12 7.0 3.8
11000 5.6 42.1 325 28 14 6.1 3.3 | 6.7 44.1 320 22 11 5.7 3.2
10500 6.5 43.7 320 27 14 6.3 3.5 | 7.5 45.5 310 22 11 5.8 3.2
10250 7.0 44.6 315 27 14 5.3 2.9 | 7.9 46.2 305 22 11 5.8 3.2
10000 7.4 45.3 315 26 13 5.3 2.9 | 8.4 47.1 305 21 11 6.6 3.6
9750 7.8 46.0 310 26 13 6.3 3.4 | 8.9 48.0 300 21 11 7.2 4.0
9500 8.3 46.9 310 25 13 6.1 3.4 | 9.4 48.9 300 21 11 7.2 3.9
9250 8.7 47.7 305 25 13 5.7 3.1 | 9.9 49.8 295 20 11 6.8 3.7
9000 9.2 48.6 305 25 13 6.2 3.4 | 10.4 50.7 295 20 10 7.5 4.1
8750 9.7 49.5 305 24 12 7.2 4.0 | 11.1 52.0 295 20 10 8.5 4.7
8500 10.2 50.4 305 23 12 7.0 3.9 | 12.3 54.1 290 19 10 8.0 4.4
8250 11.2 52.2 300 22 11 6.4 3.5 | 12.9 55.2 290 18 9 8.2 4.5
8000 11.7 53.1 300 21 11 7.7 4.2 | 13.5 56.3 290 18 9 9.4 5.1
7750 12.3 54.1 300 20 10 7.6 4.2 | 14.2 57.6 290 17 9 9.2 5.0
7500 12.8 55.0 295 18 9 6.6 3.6 | 14.9 58.8 290 16 8 8.4 4.6
7250 13.3 55.9 295 17 9 5.9 3.2 | 15.5 59.9 290 15 8 8.3 4.5
7000 13.7 56.7 295 16 8 6.8 3.7 | 16.2 61.2 285 14 7 9.5 5.2
6750 14.1 57.4 290 14 7 2.4 1.3 | 16.9 62.4 285 13 7 9.9 5.4
6500 14.0 57.2 285 12 6 -2.4 -1.3 | 17.6 63.7 285 12 6 9.5 5.2
6250 13.9 57.0 275 10 5 -0.9 -0.5 | 18.3 64.9 285 12 6 9.2 5.0
6000 13.7 56.7 260 8 4 -4.2 -2.3 | 19.0 66.2 280 11 6 11.0 6.0
5750 13.1 55.6 235 6 3 -11.2 -6.1 | 20.1 68.2 280 9 5 16.9 9.3
5500 12.3 54.1 205 5 3 -1.0 -0.6 | 21.4 70.5 275 7 4 16.6 9.1
03/18/2026 AT 1500 MDT | 03/18/2026 AT 1800 MDT
|
CAPE... 0.0 LI... +6.5 | CAPE... 0.0 LI... +6.0
CINH... -0.1 K INDEX... -12.6 | CINH... -0.3 K INDEX... -13.7
|
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 -67.7 -89.9 315 42 21 1.2 0.6 | -68.1 -90.6 310 47 24 1.4 0.7
45000 -65.1 -85.2 315 47 24 4.6 2.5 | -65.0 -85.0 305 48 25 5.2 2.8
40000 -57.5 -71.5 315 50 26 8.7 4.8 | -56.7 -70.1 310 50 26 7.4 4.1
38000 -52.6 -62.7 320 52 27 8.2 4.5 | -52.4 -62.3 315 52 27 7.1 3.9
36000 -47.7 -53.9 325 55 28 8.2 4.5 | -48.1 -54.6 320 55 28 7.1 3.9
34000 -43.1 -45.6 320 59 30 7.3 4.0 | -43.7 -46.7 320 64 33 7.4 4.1
32000 -38.8 -37.8 320 65 33 7.3 4.0 | -39.3 -38.7 320 74 38 7.4 4.1
30000 -34.2 -29.6 320 69 36 7.7 4.2 | -34.7 -30.5 320 77 40 7.7 4.2
29000 -31.9 -25.4 320 71 37 7.7 4.2 | -32.4 -26.3 320 76 39 7.7 4.2
28000 -29.6 -21.3 320 73 37 7.7 4.2 | -30.1 -22.2 320 75 39 7.7 4.2
27000 -27.3 -17.1 320 72 37 7.9 4.3 | -27.8 -18.0 320 72 37 7.6 4.2
26000 -24.3 -11.7 325 69 36 7.9 4.3 | -25.5 -13.9 320 69 35 7.6 4.2
25000 -22.0 -7.6 325 67 34 8.0 4.4 | -22.7 -8.9 320 64 33 7.6 4.2
24000 -19.8 -3.6 325 65 34 7.0 3.9 | -20.4 -4.7 320 62 32 7.7 4.2
23000 -17.7 0.1 320 63 33 7.0 3.9 | -18.1 -0.6 320 60 31 7.7 4.2
22000 -15.6 3.9 320 62 32 7.0 3.9 | -15.8 3.6 320 58 30 7.6 4.2
21000 -13.5 7.7 320 60 31 6.8 3.7 | -13.6 7.5 325 56 29 7.4 4.0
20000 -11.5 11.3 320 59 31 6.8 3.8 | -11.4 11.5 325 55 28 7.4 4.0
19500 -10.4 13.3 320 59 30 6.8 3.7 | -10.3 13.5 325 54 28 7.4 4.1
19000 -9.4 15.1 320 58 30 6.9 3.8 | -9.2 15.4 325 53 27 7.2 4.0
18500 -8.4 16.9 320 57 29 6.9 3.8 | -8.1 17.4 325 52 27 7.2 4.0
18000 -7.3 18.9 325 55 28 7.0 3.8 | -7.0 19.4 330 51 26 7.3 4.0
17500 -6.3 20.7 325 53 27 7.1 3.9 | -5.9 21.4 330 49 25 7.4 4.1
17000 -5.2 22.6 325 50 26 7.1 3.9 | -4.8 23.4 330 48 24 7.4 4.1
16500 -4.1 24.6 325 48 25 7.1 3.9 | -3.7 25.3 330 46 23 7.2 3.9
16000 -3.1 26.4 325 44 23 7.1 3.9 | -2.6 27.3 330 43 22 7.2 4.0
15500 -2.0 28.4 325 41 21 7.0 3.8 | -1.5 29.3 330 40 21 6.9 3.8
15000 -1.0 30.2 325 37 19 7.0 3.8 | -0.5 31.1 330 37 19 6.7 3.7
14500 0.0 32.0 325 33 17 6.9 3.8 | 0.5 32.9 325 33 17 6.5 3.6
14000 1.0 33.8 325 29 15 6.6 3.6 | 1.4 34.5 325 30 15 5.8 3.2
13500 2.0 35.6 320 26 13 6.6 3.6 | 2.2 36.0 325 27 14 5.9 3.3
13000 3.0 37.4 315 24 12 6.5 3.6 | 3.2 37.8 325 25 13 7.2 3.9
12500 3.9 39.0 315 23 12 6.6 3.6 | 4.2 39.6 325 24 12 7.0 3.9
12000 4.8 40.6 310 22 12 6.2 3.4 | 5.4 41.7 325 23 12 8.6 4.7
11500 5.8 42.4 305 23 12 6.1 3.3 | 6.6 43.9 320 24 12 8.4 4.6
11000 6.8 44.2 300 23 12 8.2 4.5 | 7.9 46.2 315 24 12 8.7 4.8
10500 8.0 46.4 300 23 12 7.9 4.3 | 9.2 48.6 315 25 13 8.9 4.9
10250 8.6 47.5 300 24 12 9.3 5.1 | 9.8 49.6 310 25 13 7.9 4.3
10000 9.4 48.9 300 23 12 10.0 5.5 | 10.4 50.7 310 26 13 7.9 4.3
9750 10.1 50.2 300 23 12 9.0 4.9 | 11.0 51.8 310 26 14 8.8 4.8
9500 10.7 51.3 300 23 12 9.2 5.1 | 11.7 53.1 305 27 14 8.6 4.7
9250 11.4 52.5 300 23 12 9.3 5.1 | 12.3 54.1 305 27 14 8.1 4.5
9000 12.2 54.0 300 24 12 9.8 5.4 | 12.9 55.2 305 28 14 8.1 4.4
8750 13.6 56.5 300 24 12 10.1 5.5 | 13.5 56.3 305 28 15 8.6 4.7
8500 14.4 57.9 300 24 12 8.1 4.4 | 14.7 58.5 300 29 15 7.2 3.9
8250 14.9 58.8 300 24 12 8.2 4.5 | 15.2 59.4 300 29 15 7.8 4.3
8000 15.7 60.3 300 23 12 10.8 5.9 | 15.9 60.6 300 29 15 10.1 5.6
7750 16.5 61.7 300 23 12 10.4 5.7 | 16.7 62.1 300 29 15 9.7 5.3
7500 17.2 63.0 300 23 12 9.1 5.0 | 17.4 63.3 300 29 15 8.5 4.7
7250 17.8 64.0 300 23 12 8.9 4.9 | 18.0 64.4 300 29 15 8.4 4.6
7000 18.6 65.5 300 23 12 10.1 5.5 | 18.7 65.7 300 29 15 10.1 5.5
6750 19.3 66.7 300 22 11 10.6 5.8 | 19.4 66.9 300 28 14 10.0 5.5
6500 20.1 68.2 300 21 11 10.5 5.8 | 20.1 68.2 300 26 14 8.9 4.9
6250 20.9 69.6 300 21 11 10.2 5.6 | 20.8 69.4 300 25 13 9.3 5.1
6000 21.7 71.1 300 20 10 11.2 6.2 | 21.5 70.7 300 24 12 8.5 4.7
5750 22.7 72.9 300 18 9 16.4 9.0 | 22.0 71.6 300 20 10 6.6 3.6
5500 24.1 75.4 305 14 7 23.7 13.0 | 22.5 72.5 300 15 8 7.2 4.0
________________________________________________________________________________
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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