680
UXUS97 KBOU 111232
SRGBOU
SOARING FORECAST
NATIONAL WEATHER SERVICE DENVER/BOULDER, COLORADO
0631 MDT SATURDAY, APRIL 11, 2026
THIS FORECAST IS FOR SATURDAY, APRIL 11, 2026:
IF THE TRIGGER TEMPERATURE OF 70.3 F/21.3 C IS REACHED...THEN
THERMAL SOARING INDEX....................... EXCELLENT
MAXIMUM RATE OF LIFT........................ 1189 FT/MIN (6.0 M/S)
MAXIMUM HEIGHT OF THERMALS.................. 19480 FT MSL (14166 FT AGL)
FORECAST MAXIMUM TEMPERATURE................... 77.0 F/25.5 C
TIME OF TRIGGER TEMPERATURE.................... 1045 MDT
TIME OF OVERDEVELOPMENT........................ 1400 MDT
MIDDLE/HIGH CLOUDS DURING SOARING WINDOW....... BROKEN/OVERCAST THIN MIDDLE
SURFACE WINDS DURING SOARING WINDOW............ 20 MPH OR LESS
HEIGHT OF THE -3 THERMAL INDEX................. 10956 FT MSL (5641 FT AGL)
THERMAL SOARING OUTLOOK FOR SUNDAY 04/12....... EXCELLENT
WAVE SOARING INDEX............................. POOR
WAVE SOARING INDEX TREND (TO 1800 MDT).........
HEIGHT OF STABLE LAYER (12-18K FT MSL)......... NONE
WEAK PVA/NVA (THROUGH 1800 MDT)................ NEITHER
POTENTIAL HEIGHT OF WAVE....................... 39321 FT MSL (34007 FT AGL)
WAVE SOARING OUTLOOK FOR SUNDAY 04/12.......... POOR
REMARKS...
SUNRISE/SUNSET.................... 06:27:19 / 19:33:33 MDT
TOTAL POSSIBLE SUNSHINE........... 13 HR 6 MIN 14 SEC (786 MIN 14 SEC)
ALTITUDE OF SUN AT 13:00:26 MDT... 58.77 DEGREES
UPPER AIR DATA FROM NUMERICAL MODEL FORECAST VALID ON 04/11/2026 AT 0600 MDT
FREEZING LEVEL.................. 12690 FT MSL (7376 FT AGL)
CONVECTIVE CONDENSATION LEVEL... 15168 FT MSL (9854 FT AGL)
LIFTED CONDENSATION LEVEL....... 16201 FT MSL (10887 FT AGL)
LIFTED INDEX.................... -2.7
K INDEX......................... +19.1
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 -60.2 -76.4 250 39 20 0.2 0.1 M M M M M
45000 -60.0 -76.0 240 49 25 -1.4 -0.8 M M M M M
40000 -63.3 -81.9 225 66 34 -2.3 -1.2 M M M M M
38000 -61.4 -78.5 220 68 35 6.9 3.8 M M M M M
36000 -57.2 -71.0 220 68 35 6.9 3.8 M M M M M
34000 -52.1 -61.8 215 66 34 8.5 4.7 M M M M M
32000 -47.0 -52.6 215 62 32 8.5 4.7 M M M M M
30000 -41.8 -43.2 215 60 31 8.9 4.9 33.4 92.1 6.3 M M
29000 -39.1 -38.4 215 60 31 8.9 4.9 33.0 91.5 6.1 M M
28000 -36.4 -33.5 215 60 31 8.9 4.9 32.8 91.0 6.0 M M
27000 -33.9 -29.0 215 58 30 7.3 4.0 32.4 90.3 5.8 M M
26000 -31.6 -24.9 215 54 28 7.5 4.1 31.4 88.6 5.1 M M
25000 -29.4 -20.9 220 49 25 7.5 4.1 30.6 87.1 4.4 M M
24000 -27.2 -17.0 220 44 23 7.0 3.8 29.8 85.7 3.8 M M
23000 -25.1 -13.2 220 39 20 6.9 3.8 28.7 83.6 2.9 M M
22000 -23.1 -9.6 225 35 18 6.9 3.8 27.7 81.8 2.1 M M
21000 -21.0 -5.8 225 30 16 7.2 4.7 26.7 80.1 1.3 M M
20000 -18.9 -2.0 230 27 14 7.2 3.9 25.7 78.3 0.5 M M
19500 -17.8 -0.0 235 26 13 7.2 3.9 25.3 77.5 0.1 M M
19000 -16.7 1.9 240 24 12 7.2 3.9 24.9 76.8 -0.3 1354 6.9
18500 -15.7 3.7 240 23 12 7.5 4.1 24.5 76.1 -0.6 1307 6.6
18000 -14.0 6.8 240 20 10 7.4 4.1 23.9 75.0 -1.2 1236 6.3
17500 -12.9 8.8 240 18 9 8.7 4.8 23.6 74.5 -1.5 1186 6.0
17000 -11.6 11.1 240 17 9 8.7 4.8 23.4 74.1 -1.7 1133 5.8
16500 -10.3 13.5 235 15 8 8.9 4.9 23.3 73.9 -1.9 1079 5.5
16000 -8.9 16.0 235 13 7 9.0 5.0 23.1 73.6 -2.0 1024 5.2
15500 -7.6 18.3 230 11 6 9.1 5.0 23.0 73.4 -2.1 968 4.9
15000 -6.2 20.8 225 11 6 9.1 5.0 22.9 73.2 -2.3 913 4.6
14500 -4.9 23.2 225 11 5 9.1 5.0 22.8 73.0 -2.4 858 4.4
14000 -3.5 25.7 225 11 6 9.2 5.1 22.7 72.9 -2.5 802 4.1
13500 -2.2 28.0 225 11 6 9.2 5.0 22.6 72.7 -2.6 747 3.8
13000 -0.8 30.6 225 12 6 9.7 5.3 22.6 72.6 -2.7 690 3.5
12500 0.7 33.3 230 12 6 9.7 5.3 22.5 72.6 -2.7 632 3.2
12000 2.1 35.8 230 13 7 9.3 5.1 22.5 72.5 -2.8 575 2.9
11500 3.5 38.3 235 13 7 9.3 5.1 22.4 72.4 -2.9 519 2.6
11000 4.8 40.6 235 13 7 9.4 5.2 22.4 72.3 -3.0 463 2.4
10500 6.2 43.2 240 14 7 10.0 5.5 22.3 72.1 -3.1 407 2.1
10250 6.9 44.4 240 14 7 6.9 3.8 22.3 72.1 -3.1 378 1.9
10000 7.3 45.1 245 14 7 7.1 3.9 21.9 71.5 -3.5 359 1.8
9750 8.0 46.4 245 13 7 10.1 5.6 21.9 71.5 -3.5 330 1.7
9500 8.7 47.7 250 13 7 9.8 5.4 21.9 71.5 -3.5 301 1.5
9250 9.5 49.1 255 13 7 8.1 4.4 21.9 71.4 -3.6 273 1.4
9000 9.9 49.8 255 13 7 5.9 3.2 21.7 71.0 -3.8 251 1.3
8750 10.4 50.7 260 13 7 6.4 3.5 21.4 70.5 -4.1 230 1.2
8500 10.8 51.4 265 13 6 6.5 3.6 21.1 70.0 -4.4 209 1.1
8250 11.3 52.3 270 13 6 5.8 3.2 20.9 69.6 -4.7 187 1.0
8000 11.7 53.1 275 13 7 4.5 2.5 20.5 68.9 -5.1 169 0.9
7750 12.0 53.6 280 13 7 3.8 2.1 20.1 68.1 -5.5 153 0.8
7500 12.2 54.0 285 13 7 3.1 1.7 19.6 67.2 -6.0 138 0.7
7250 12.4 54.3 290 12 6 1.4 0.8 19.0 66.2 -6.6 126 0.6
7000 12.4 54.3 290 12 6 0.2 0.1 18.3 65.0 -7.3 118 0.6
6750 12.4 54.3 290 11 6 -0.0 -0.0 17.6 63.6 -8.1 111 0.6
6500 12.2 54.0 290 10 5 -3.7 -2.0 16.7 62.1 -9.0 108 0.5
6250 11.8 53.2 290 9 4 -7.2 -3.9 15.5 60.0 -10.2 114 0.6
6000 11.2 52.2 285 7 4 -7.0 -3.8 14.2 57.6 -11.5 124 0.6
5750 10.6 51.1 275 6 3 -8.3 -4.6 13.0 55.4 -12.9 134 0.7
5500 9.7 49.5 255 6 3 -15.9 -8.7 11.4 52.5 -14.5 154 0.8
* * * * * * NUMERICAL WEATHER PREDICTION MODEL FORECAST DATA VALID * * * * * *
04/11/2026 AT 0900 MDT | 04/11/2026 AT 1200 MDT
|
CAPE... 0.0 LI... -1.0 | CAPE... +58.6 LI... -0.2
CINH... -0.2 K INDEX... +20.5 | CINH... -13.1 K INDEX... +20.8
|
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 -59.7 -75.5 245 39 20 0.4 0.2 | -58.6 -73.5 240 37 19 0.1 0.1
45000 -59.1 -74.4 235 57 30 -1.1 -0.6 | -58.5 -73.3 235 64 33 -1.0 -0.5
40000 -62.1 -79.8 230 66 34 -2.0 -1.1 | -61.7 -79.1 225 70 36 -2.1 -1.2
38000 -60.6 -77.1 225 68 35 6.1 3.3 | -60.1 -76.2 225 71 37 5.5 3.0
36000 -56.5 -69.7 215 69 36 6.1 3.3 | -56.8 -70.2 220 71 36 5.5 3.0
34000 -52.2 -62.0 215 68 35 8.7 4.8 | -52.9 -63.2 220 68 35 8.5 4.7
32000 -47.0 -52.6 215 63 33 8.7 4.8 | -47.8 -54.0 220 62 32 8.5 4.7
30000 -41.9 -43.4 215 60 31 8.3 4.5 | -42.7 -44.9 220 57 30 8.2 4.5
29000 -39.4 -38.9 215 60 31 8.3 4.5 | -40.3 -40.5 220 56 29 8.2 4.5
28000 -36.9 -34.4 215 60 31 8.3 4.5 | -37.2 -35.0 220 54 28 8.2 4.5
27000 -34.5 -30.1 215 59 30 6.8 3.7 | -34.8 -30.6 220 52 27 8.1 4.5
26000 -32.4 -26.3 220 54 28 6.9 3.8 | -32.4 -26.3 225 49 25 8.1 4.5
25000 -30.3 -22.5 220 48 25 6.9 3.8 | -29.9 -21.8 225 47 24 8.1 4.5
24000 -28.3 -18.9 225 43 22 7.1 3.9 | -27.5 -17.5 230 45 23 7.8 4.3
23000 -26.1 -15.0 230 38 20 7.1 3.9 | -25.2 -13.4 230 43 22 7.8 4.3
22000 -24.0 -11.2 235 33 17 7.1 3.9 | -22.9 -9.2 230 40 21 7.8 4.3
21000 -21.9 -7.4 240 29 15 7.8 4.3 | -20.6 -5.1 235 39 20 7.7 4.2
20000 -19.6 -3.3 240 27 14 7.7 4.3 | -18.3 -0.9 235 38 19 7.7 4.2
19500 -18.4 -1.1 240 26 13 7.8 4.3 | -17.1 1.2 235 37 19 7.8 4.3
19000 -17.3 0.9 245 25 13 7.7 4.2 | -16.0 3.2 240 37 19 7.8 4.3
18500 -15.4 4.3 245 24 12 8.8 4.8 | -14.9 5.2 240 36 19 7.1 3.9
18000 -14.1 6.6 245 24 12 8.8 4.8 | -13.8 7.2 240 36 18 7.2 3.9
17500 -12.9 8.8 250 23 12 8.5 4.7 | -12.8 9.0 245 35 18 7.5 4.1
17000 -11.6 11.1 250 23 12 8.5 4.7 | -11.7 10.9 245 34 17 7.8 4.3
16500 -10.3 13.5 250 22 11 8.4 4.6 | -10.5 13.1 245 32 17 7.8 4.3
16000 -9.1 15.6 255 20 10 8.3 4.5 | -9.4 15.1 245 30 16 8.1 4.4
15500 -7.9 17.8 255 18 9 8.3 4.5 | -8.2 17.2 245 28 14 8.0 4.4
15000 -6.7 19.9 255 16 8 8.3 4.6 | -7.0 19.4 240 25 13 8.4 4.6
14500 -5.4 22.3 255 14 7 8.2 4.5 | -5.1 22.8 240 21 11 8.5 4.7
14000 -4.1 24.6 255 13 7 9.4 5.2 | -3.9 25.0 235 20 10 7.8 4.3
13500 -2.7 27.1 245 12 6 9.4 5.1 | -2.8 27.0 230 18 9 7.8 4.3
13000 -1.4 29.5 240 12 6 8.8 4.8 | -1.6 29.1 225 17 9 8.3 4.6
12500 -0.1 31.8 235 12 6 8.8 4.8 | -0.4 31.3 220 16 8 8.3 4.6
12000 1.3 34.3 230 12 6 9.1 5.0 | 0.9 33.6 215 16 8 9.0 5.0
11500 2.6 36.7 225 12 6 9.1 5.0 | 2.2 36.0 210 16 8 9.2 5.0
11000 4.0 39.2 220 12 6 9.2 5.1 | 3.5 38.3 210 15 8 7.9 4.3
10500 5.3 41.5 225 12 6 10.1 5.5 | 4.7 40.5 205 15 8 6.8 3.7
10250 6.0 42.8 225 12 6 6.1 3.3 | 5.3 41.5 205 14 7 11.5 6.3
10000 6.3 43.3 225 11 6 7.2 4.0 | 6.3 43.3 205 14 7 12.8 7.0
9750 7.1 44.8 230 11 6 11.7 6.4 | 7.0 44.6 205 14 7 8.9 4.9
9500 7.9 46.2 230 10 5 11.3 6.2 | 7.7 45.9 205 13 7 10.1 5.6
9250 8.7 47.7 235 10 5 8.4 4.6 | 8.4 47.1 205 13 7 9.0 4.9
9000 9.2 48.6 240 10 5 7.3 4.0 | 9.1 48.4 205 13 7 9.3 5.1
8750 9.9 49.8 240 9 5 9.8 5.4 | 9.8 49.6 205 13 7 10.3 5.7
8500 10.6 51.1 240 9 5 9.2 5.0 | 10.6 51.1 205 13 7 10.0 5.5
8250 11.3 52.3 240 9 4 9.2 5.1 | 11.3 52.3 205 13 7 10.4 5.7
8000 11.9 53.4 240 8 4 8.3 4.5 | 12.1 53.8 210 13 7 10.4 5.7
7750 12.5 54.5 240 8 4 6.9 3.8 | 12.9 55.2 210 13 7 10.0 5.5
7500 13.0 55.4 240 8 4 6.1 3.4 | 13.6 56.5 210 13 7 10.0 5.5
7250 13.4 56.1 240 8 4 5.1 2.8 | 14.4 57.9 210 13 6 10.3 5.7
7000 13.7 56.7 240 8 4 4.3 2.4 | 15.1 59.2 210 12 6 10.5 5.7
6750 14.1 57.4 245 7 4 4.5 2.5 | 15.9 60.6 210 12 6 9.7 5.3
6500 14.3 57.7 240 7 4 1.7 0.9 | 16.6 61.9 210 12 6 10.1 5.5
6250 14.3 57.7 235 7 4 -1.2 -0.7 | 17.4 63.3 210 12 6 11.3 6.2
6000 14.2 57.6 230 7 3 -1.0 -0.5 | 18.3 64.9 210 12 6 11.3 6.2
5750 14.1 57.4 220 6 3 -2.7 -1.5 | 19.1 66.4 210 11 6 10.9 6.0
5500 13.9 57.0 215 6 3 0.4 0.2 | 20.1 68.2 210 11 6 17.5 9.6
04/11/2026 AT 1500 MDT | 04/11/2026 AT 1800 MDT
|
CAPE... +135.4 LI... -0.9 | CAPE... +332.4 LI... -1.0
CINH... -1.8 K INDEX... +23.8 | CINH... -91.9 K INDEX... +18.5
|
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 -58.4 -73.1 235 42 22 0.8 0.4 | -59.4 -74.9 240 45 23 0.3 0.2
45000 -57.2 -71.0 235 64 33 -0.8 -0.4 | -58.9 -74.0 235 61 31 -0.7 -0.4
40000 -61.4 -78.5 230 73 37 -2.8 -1.5 | -60.9 -77.6 230 72 37 -1.3 -0.7
38000 -60.1 -76.2 225 74 38 5.3 2.9 | -59.1 -74.4 225 80 41 5.3 2.9
36000 -56.9 -70.4 225 75 39 5.3 2.9 | -55.9 -68.6 225 89 46 5.3 2.9
34000 -53.2 -63.8 225 75 39 8.6 4.7 | -52.0 -61.6 220 92 47 8.6 4.7
32000 -48.0 -54.4 225 73 38 8.7 4.8 | -46.8 -52.2 225 83 43 8.6 4.7
30000 -42.8 -45.0 225 72 37 8.4 4.6 | -41.9 -43.4 230 72 37 7.5 4.1
29000 -40.3 -40.5 225 72 37 8.4 4.6 | -39.6 -39.3 230 65 34 7.5 4.1
28000 -37.2 -35.0 230 72 37 8.4 4.6 | -37.4 -35.3 230 59 30 7.5 4.1
27000 -34.7 -30.5 230 70 36 8.2 4.5 | -35.1 -31.2 230 53 27 7.6 4.2
26000 -32.2 -26.0 235 64 33 8.2 4.5 | -32.8 -27.0 230 50 26 7.6 4.2
25000 -29.8 -21.6 235 57 30 8.3 4.5 | -30.5 -22.9 230 47 24 7.7 4.2
24000 -27.3 -17.1 235 51 26 8.5 4.7 | -28.2 -18.8 230 44 23 8.3 4.6
23000 -24.8 -12.6 235 47 24 8.5 4.7 | -25.6 -14.1 235 44 22 8.7 4.8
22000 -22.3 -8.1 235 42 22 8.5 4.7 | -22.9 -9.2 235 43 22 8.7 4.8
21000 -19.9 -3.8 235 38 20 6.6 3.6 | -20.3 -4.5 240 41 21 8.5 4.7
20000 -17.9 -0.2 235 36 19 6.8 3.7 | -17.2 1.0 235 35 18 8.6 4.7
19500 -16.9 1.6 235 36 18 6.8 3.7 | -15.9 3.4 235 33 17 8.6 4.7
19000 -15.9 3.4 230 35 18 6.8 3.7 | -14.6 5.7 230 30 16 8.6 4.7
18500 -14.9 5.2 230 34 17 7.8 4.3 | -13.5 7.7 235 30 15 7.3 4.0
18000 -13.7 7.3 230 32 16 7.8 4.3 | -12.4 9.7 235 31 16 7.4 4.1
17500 -12.6 9.3 225 30 16 7.9 4.3 | -11.2 11.8 240 31 16 7.7 4.2
17000 -11.4 11.5 225 30 15 8.1 4.4 | -10.1 13.8 240 32 16 7.9 4.3
16500 -10.2 13.6 220 30 15 8.1 4.4 | -8.9 16.0 240 32 17 8.0 4.4
16000 -9.0 15.8 215 29 15 8.3 4.6 | -7.7 18.1 240 32 17 8.3 4.5
15500 -7.8 18.0 210 28 14 8.3 4.5 | -6.5 20.3 240 32 17 8.4 4.6
15000 -6.6 20.1 205 27 14 8.8 4.8 | -5.3 22.5 240 32 16 7.6 4.2
14500 -4.6 23.7 200 25 13 8.9 4.9 | -4.2 24.4 240 31 16 7.7 4.2
14000 -3.3 26.1 200 24 12 9.6 5.3 | -3.1 26.4 240 29 15 8.5 4.7
13500 -1.8 28.8 200 22 11 9.6 5.3 | -1.8 28.8 240 28 14 8.6 4.7
13000 -0.4 31.3 200 21 11 9.4 5.1 | -0.6 30.9 240 26 14 9.3 5.1
12500 1.0 33.8 200 20 10 9.3 5.1 | 0.8 33.4 235 25 13 9.7 5.3
12000 2.4 36.3 200 19 10 9.7 5.3 | 2.2 36.0 235 23 12 9.4 5.1
11500 3.8 38.8 200 19 10 9.8 5.4 | 3.6 38.5 235 21 11 9.0 5.0
11000 5.3 41.5 200 18 9 9.2 5.1 | 4.9 40.8 235 19 10 8.5 4.7
10500 6.6 43.9 200 17 9 8.4 4.6 | 6.1 43.0 235 17 9 7.7 4.2
10250 7.3 45.1 200 17 9 11.3 6.2 | 6.7 44.1 235 16 8 8.7 4.8
10000 8.2 46.8 205 16 8 11.6 6.4 | 7.4 45.3 240 15 8 8.7 4.8
9750 9.0 48.2 205 16 8 9.1 5.0 | 7.9 46.2 240 14 7 7.6 4.2
9500 9.7 49.5 205 15 8 9.6 5.3 | 8.5 47.3 245 13 7 7.9 4.3
9250 10.4 50.7 205 15 8 10.1 5.5 | 9.1 48.4 245 13 7 7.9 4.3
9000 11.2 52.2 210 14 7 10.0 5.5 | 9.7 49.5 250 12 6 7.3 4.0
8750 11.9 53.4 210 14 7 9.4 5.1 | 10.2 50.4 255 12 6 6.8 3.8
8500 12.6 54.7 210 13 7 9.3 5.1 | 10.7 51.3 260 12 6 6.7 3.7
8250 13.3 55.9 215 13 6 10.3 5.7 | 11.2 52.2 265 12 6 7.7 4.2
8000 14.1 57.4 220 12 6 10.5 5.8 | 11.8 53.2 265 12 6 8.9 4.9
7750 14.8 58.6 220 12 6 9.3 5.1 | 12.5 54.5 270 12 6 7.6 4.1
7500 15.5 59.9 225 11 6 8.8 4.9 | 13.0 55.4 275 13 6 6.5 3.5
7250 16.2 61.2 225 11 6 10.4 5.7 | 13.5 56.3 275 13 7 7.6 4.2
7000 17.0 62.6 230 11 6 11.6 6.3 | 14.1 57.4 280 13 6 8.5 4.7
6750 17.8 64.0 230 10 5 9.6 5.3 | 14.6 58.3 280 12 6 6.5 3.6
6500 18.5 65.3 230 10 5 9.1 5.0 | 15.0 59.0 285 11 6 5.1 2.8
6250 19.2 66.6 235 10 5 10.6 5.8 | 15.4 59.7 290 10 5 7.1 3.9
6000 20.1 68.2 235 10 5 11.9 6.5 | 15.9 60.6 295 7 3 8.6 4.7
5750 20.9 69.6 240 9 5 9.9 5.4 | 16.5 61.7 310 4 2 7.5 4.1
5500 21.7 71.1 240 9 5 14.8 8.1 | 17.1 62.8 320 3 2 11.0 6.1
________________________________________________________________________________
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.
042613
CLICK HERE TO GO TO PREVIOUS BULLETINS.
Main Text Page