194
UXUS97 KBOU 210054
SRGBOU
SOARING FORECAST
NATIONAL WEATHER SERVICE DENVER/BOULDER, COLORADO
1852 MDT MONDAY, JULY 20, 2026
THIS FORECAST IS FOR TUESDAY, JULY 21, 2026:
IF THE TRIGGER TEMPERATURE OF 86.7 F/30.4 C IS REACHED...THEN
THERMAL SOARING INDEX....................... EXCELLENT
MAXIMUM RATE OF LIFT........................ 959 FT/MIN (4.9 M/S)
MAXIMUM HEIGHT OF THERMALS.................. 16155 FT MSL (10795 FT AGL)
FORECAST MAXIMUM TEMPERATURE................... 95.0 F/35.5 C
TIME OF TRIGGER TEMPERATURE.................... 1230 MDT
TIME OF OVERDEVELOPMENT........................ 1700 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................. 10614 FT MSL (5253 FT AGL)
THERMAL SOARING OUTLOOK FOR WEDNESDAY 07/22.... 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)................ WEAK PVA
POTENTIAL HEIGHT OF WAVE....................... 14966 FT MSL (9606 FT AGL)
WAVE SOARING OUTLOOK FOR WEDNESDAY 07/22....... POOR
REMARKS...
SUNRISE/SUNSET.................... 05:49:09 / 20:22:45 MDT
TOTAL POSSIBLE SUNSHINE........... 14 HR 33 MIN 36 SEC (873 MIN 36 SEC)
ALTITUDE OF SUN AT 13:05:57 MDT... 70.54 DEGREES
UPPER AIR DATA FROM NUMERICAL MODEL FORECAST VALID ON 07/21/2026 AT 0600 MDT
FREEZING LEVEL.................. 17617 FT MSL (12257 FT AGL)
CONVECTIVE CONDENSATION LEVEL... 15257 FT MSL (9897 FT AGL)
LIFTED CONDENSATION LEVEL....... 15702 FT MSL (10342 FT AGL)
LIFTED INDEX.................... -2.8
K INDEX......................... +28.8
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 -67.0 -88.6 300 5 3 3.3 1.8 M M M M M
45000 -59.3 -74.7 285 5 3 7.6 4.2 M M M M M
40000 -47.9 -54.2 230 2 1 7.7 4.2 M M M M M
38000 -43.3 -45.9 170 2 1 7.7 4.2 M M M M M
36000 -38.2 -36.8 135 4 2 7.0 3.8 M M M M M
34000 -34.0 -29.2 130 5 3 7.0 3.8 M M M M M
32000 -29.8 -21.6 130 7 3 7.2 4.0 52.6 126.7 13.2 M M
30000 -25.6 -14.1 155 6 3 7.1 3.9 50.3 122.6 11.7 M M
29000 -23.4 -10.1 170 6 3 7.1 3.9 49.4 120.9 11.1 M M
28000 -21.2 -6.2 175 6 3 7.8 4.3 48.5 119.3 10.6 M M
27000 -18.9 -2.0 175 3 2 7.8 4.3 47.7 117.9 10.0 M M
26000 -16.6 2.1 175 1 1 7.9 4.3 47.0 116.6 9.5 M M
25000 -14.3 6.3 000 0 0 6.7 3.7 46.3 115.4 9.0 M M
24000 -12.5 9.5 160 2 1 6.5 3.6 45.0 113.0 8.0 M M
23000 -10.6 12.9 165 3 2 6.6 3.6 43.9 110.9 7.1 M M
22000 -8.7 16.3 165 5 2 6.9 3.8 42.8 109.1 6.2 M M
21000 -6.1 21.0 180 5 3 7.0 3.8 41.5 106.7 5.1 M M
20000 -4.0 24.8 190 6 3 7.1 3.9 40.6 105.1 4.3 M M
19500 -3.0 26.6 190 6 3 6.6 3.6 40.1 104.2 3.9 M M
19000 -2.1 28.2 185 6 3 6.5 3.6 39.6 103.2 3.4 M M
18500 -1.1 30.0 180 7 4 6.3 3.5 39.0 102.2 2.9 M M
18000 -0.4 31.3 170 7 4 4.7 2.6 38.2 100.8 2.2 M M
17500 0.2 32.4 155 8 4 4.7 2.6 37.4 99.3 1.4 M M
17000 1.0 33.8 150 9 5 6.8 3.7 36.7 98.0 0.7 M M
16500 2.0 35.6 145 9 5 7.3 4.0 36.2 97.2 0.2 M M
16000 3.1 37.6 145 9 5 7.2 4.0 35.8 96.5 -0.2 940 4.8
15500 4.1 39.4 145 10 5 7.0 3.9 35.4 95.7 -0.6 895 4.5
15000 5.1 41.2 140 10 5 6.9 3.8 34.9 94.9 -1.1 850 4.3
14500 6.2 43.2 140 11 6 8.9 4.9 34.6 94.4 -1.4 801 4.1
14000 7.5 45.5 140 11 6 8.7 4.8 34.5 94.0 -1.6 748 3.8
13500 8.8 47.8 135 11 6 9.1 5.0 34.3 93.8 -1.8 694 3.5
13000 10.1 50.2 135 11 5 9.2 5.0 34.2 93.6 -1.9 640 3.2
12500 11.4 52.5 135 10 5 8.9 4.9 34.1 93.4 -2.1 585 3.0
12000 12.7 54.9 140 9 5 8.8 4.8 34.0 93.2 -2.2 531 2.7
11500 14.0 57.2 145 8 4 8.3 4.6 33.8 92.9 -2.4 478 2.4
11000 15.2 59.4 155 6 3 7.7 4.2 33.5 92.4 -2.7 429 2.2
10500 16.3 61.3 165 4 2 5.2 2.9 33.2 91.8 -3.1 380 1.9
10250 16.6 61.9 160 4 2 5.0 2.8 32.8 91.0 -3.5 364 1.8
10000 17.1 62.8 175 2 1 8.1 4.4 32.6 90.6 -3.7 341 1.7
9750 17.6 63.7 210 1 1 7.8 4.3 32.4 90.3 -3.9 317 1.6
9500 18.2 64.8 280 1 1 6.0 3.3 32.2 90.0 -4.1 293 1.5
9250 18.5 65.3 305 2 1 3.7 2.1 31.8 89.3 -4.5 277 1.4
9000 18.8 65.8 315 3 2 3.8 2.1 31.4 88.5 -5.0 261 1.3
8750 19.0 66.2 325 5 3 4.0 2.2 30.9 87.6 -5.5 246 1.3
8500 19.3 66.7 325 7 3 2.6 1.4 30.4 86.8 -6.0 232 1.2
8250 19.3 66.7 330 7 4 0.9 0.5 29.8 85.6 -6.7 222 1.1
8000 19.4 66.9 335 8 4 2.1 1.1 29.1 84.5 -7.3 212 1.1
7750 19.6 67.3 340 8 4 3.2 1.7 28.6 83.5 -7.9 200 1.0
7500 19.8 67.6 350 9 5 4.1 2.3 28.1 82.6 -8.4 185 0.9
7250 20.1 68.2 360 10 5 4.7 2.6 27.7 81.9 -8.9 168 0.9
7000 20.5 68.9 010 11 6 4.6 2.5 27.3 81.2 -9.3 151 0.8
6750 20.8 69.4 020 13 7 4.3 2.4 26.9 80.5 -9.7 135 0.7
6500 21.0 69.8 020 13 7 4.0 2.2 26.5 79.7 -10.2 119 0.6
6250 21.3 70.3 010 13 7 3.8 2.1 26.1 78.9 -10.7 104 0.5
6000 21.6 70.9 005 13 7 4.4 2.4 25.6 78.1 -11.2 88 0.4
5750 21.9 71.4 355 13 7 4.4 2.4 25.3 77.5 -11.6 72 0.4
5500 22.1 71.8 350 10 5 2.5 1.4 24.8 76.6 -12.1 57 0.3
* * * * * * NUMERICAL WEATHER PREDICTION MODEL FORECAST DATA VALID * * * * * *
07/21/2026 AT 0900 MDT | 07/21/2026 AT 1200 MDT
|
CAPE... +541.2 LI... -2.0 | CAPE... +939.6 LI... -3.3
CINH... -164.0 K INDEX... +26.4 | CINH... -52.0 K INDEX... +23.4
|
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 -66.4 -87.5 290 5 2 3.1 1.7 | -66.4 -87.5 270 6 3 3.2 1.8
45000 -59.0 -74.2 250 6 3 7.2 4.0 | -58.9 -74.0 235 8 4 7.3 4.0
40000 -48.1 -54.6 200 6 3 7.6 4.2 | -47.9 -54.2 210 12 6 7.4 4.1
38000 -43.5 -46.3 195 7 3 7.6 4.2 | -42.9 -45.2 200 10 5 7.4 4.1
36000 -38.4 -37.1 185 7 4 7.0 3.8 | -38.5 -37.3 195 9 5 6.7 3.7
34000 -34.2 -29.6 180 6 3 7.0 3.8 | -34.5 -30.1 195 8 4 6.7 3.7
32000 -30.0 -22.0 170 5 3 7.2 4.0 | -30.4 -22.7 190 8 4 7.7 4.2
30000 -25.8 -14.4 190 6 3 7.0 3.8 | -25.9 -14.6 195 9 5 7.5 4.1
29000 -23.7 -10.7 200 7 3 7.0 3.9 | -23.7 -10.7 195 10 5 7.6 4.1
28000 -21.5 -6.7 205 6 3 7.8 4.3 | -21.3 -6.3 200 9 5 8.1 4.4
27000 -19.2 -2.6 205 5 2 7.8 4.3 | -18.9 -2.0 205 7 4 8.1 4.4
26000 -16.9 1.6 210 3 2 7.9 4.3 | -16.5 2.3 215 5 3 8.1 4.4
25000 -14.7 5.5 210 2 1 6.1 3.4 | -14.2 6.4 230 3 2 6.0 3.3
24000 -12.9 8.8 180 3 1 6.0 3.3 | -12.5 9.5 200 4 2 5.8 3.2
23000 -11.2 11.8 165 4 2 6.1 3.3 | -10.9 12.4 185 5 3 5.9 3.3
22000 -9.5 14.9 160 5 3 6.7 3.7 | -9.2 15.4 175 6 3 6.2 3.4
21000 -7.0 19.4 175 6 3 6.8 3.8 | -6.9 19.6 175 7 4 6.3 3.5
20000 -5.0 23.0 180 6 3 6.8 3.7 | -5.1 22.8 170 8 4 6.2 3.4
19500 -4.0 24.8 180 7 3 7.6 4.1 | -4.1 24.6 170 8 4 7.9 4.4
19000 -2.8 27.0 180 7 4 7.6 4.2 | -2.9 26.8 170 9 4 8.0 4.4
18500 -1.6 29.1 175 8 4 7.5 4.1 | -1.6 29.1 165 9 5 7.9 4.3
18000 -0.5 31.1 175 9 5 7.2 4.0 | -0.5 31.1 165 10 5 7.3 4.0
17500 0.5 32.9 170 10 5 7.3 4.0 | 0.6 33.1 160 10 5 7.4 4.0
17000 1.6 34.9 165 11 5 6.4 3.5 | 1.7 35.1 160 11 6 6.5 3.6
16500 2.4 36.3 160 11 5 6.3 3.5 | 2.6 36.7 160 11 6 6.5 3.6
16000 3.3 37.9 160 11 6 6.7 3.7 | 3.5 38.3 160 11 6 6.7 3.7
15500 4.3 39.7 155 11 6 7.3 4.0 | 4.6 40.3 160 12 6 7.2 3.9
15000 5.3 41.5 155 11 6 7.4 4.0 | 5.6 42.1 165 12 6 7.2 3.9
14500 6.4 43.5 150 11 6 7.8 4.3 | 6.6 43.9 165 12 6 7.1 3.9
14000 7.6 45.7 150 12 6 7.7 4.2 | 7.6 45.7 165 12 6 7.1 3.9
13500 8.7 47.7 145 12 6 8.0 4.4 | 8.6 47.5 165 13 6 7.5 4.1
13000 9.9 49.8 140 12 6 8.0 4.4 | 9.7 49.5 160 13 7 7.6 4.1
12500 11.1 52.0 135 11 6 8.3 4.6 | 10.8 51.4 160 13 7 7.6 4.2
12000 12.2 54.0 130 11 5 8.5 4.7 | 11.9 53.4 155 13 7 7.7 4.2
11500 13.4 56.1 125 10 5 8.1 4.5 | 12.9 55.2 150 12 6 7.8 4.3
11000 14.5 58.1 120 8 4 7.7 4.2 | 14.0 57.2 145 12 6 7.8 4.3
10500 15.6 60.1 115 7 4 4.0 2.2 | 15.0 59.0 145 11 6 4.7 2.6
10250 15.7 60.3 110 7 4 2.4 1.3 | 15.2 59.4 145 11 6 6.1 3.3
10000 16.1 61.0 100 6 3 5.5 3.0 | 15.9 60.6 140 10 5 10.2 5.6
9750 16.4 61.5 085 5 2 5.0 2.7 | 16.6 61.9 135 9 5 9.4 5.1
9500 16.7 62.1 065 4 2 3.5 1.9 | 17.2 63.0 130 8 4 7.3 4.0
9250 16.9 62.4 055 5 3 1.9 1.1 | 17.6 63.7 125 7 4 5.9 3.2
9000 17.0 62.6 050 6 3 2.9 1.6 | 18.1 64.6 120 7 3 8.2 4.5
8750 17.2 63.0 045 6 3 3.1 1.7 | 18.7 65.7 115 6 3 8.6 4.7
8500 17.4 63.3 040 7 3 3.4 1.8 | 19.2 66.6 110 5 3 7.0 3.8
8250 17.6 63.7 045 8 4 3.4 1.9 | 19.7 67.5 110 5 3 5.2 2.9
8000 17.8 64.0 045 9 4 4.0 2.2 | 20.1 68.2 110 5 3 8.1 4.4
7750 18.1 64.6 045 9 4 4.7 2.6 | 20.8 69.4 105 5 2 10.0 5.5
7500 18.4 65.1 040 8 4 4.3 2.4 | 21.4 70.5 105 4 2 8.0 4.4
7250 18.7 65.7 035 7 4 3.7 2.0 | 22.0 71.6 100 4 2 6.6 3.6
7000 18.9 66.0 025 7 3 5.2 2.8 | 22.5 72.5 100 4 2 9.8 5.4
6750 19.4 66.9 015 6 3 8.7 4.8 | 23.3 73.9 095 4 2 12.5 6.9
6500 20.1 68.2 010 6 3 9.3 5.1 | 24.2 75.6 095 4 2 10.4 5.7
6250 20.7 69.3 010 6 3 9.2 5.0 | 24.9 76.8 090 4 2 10.2 5.6
6000 21.3 70.3 010 6 3 7.4 4.0 | 25.6 78.1 090 4 2 9.2 5.1
5750 21.9 71.4 005 7 3 11.2 6.2 | 26.5 79.7 085 3 2 17.4 9.5
5500 23.2 73.8 005 6 3 23.6 13.0 | 28.4 83.1 080 3 2 34.2 18.8
07/21/2026 AT 1500 MDT | 07/21/2026 AT 1800 MDT
|
CAPE... +678.2 LI... -2.3 | CAPE... +367.2 LI... -2.2
CINH... -6.1 K INDEX... +29.3 | CINH... -13.8 K INDEX... +32.7
|
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 -66.7 -88.1 270 8 4 3.7 2.0 | -66.6 -87.9 275 10 5 3.6 2.0
45000 -58.8 -73.8 245 12 6 7.4 4.0 | -58.9 -74.0 265 15 8 7.1 3.9
40000 -47.0 -52.6 230 14 7 7.7 4.2 | -47.4 -53.3 260 17 9 7.9 4.3
38000 -42.4 -44.3 225 13 7 7.7 4.2 | -42.7 -44.9 265 16 8 7.9 4.3
36000 -37.9 -36.2 220 13 7 6.8 3.8 | -37.9 -36.2 265 16 8 7.9 4.4
34000 -33.7 -28.7 220 12 6 6.9 3.8 | -33.2 -27.8 265 15 8 7.9 4.4
32000 -29.6 -21.3 220 12 6 6.9 3.8 | -28.5 -19.3 265 14 7 6.5 3.6
30000 -25.6 -14.1 205 11 6 6.8 3.7 | -24.8 -12.6 250 10 5 6.2 3.4
29000 -23.5 -10.3 195 11 6 6.8 3.7 | -22.9 -9.2 235 9 5 6.2 3.4
28000 -21.3 -6.3 195 10 5 8.2 4.5 | -20.8 -5.4 230 8 4 7.9 4.3
27000 -18.8 -1.8 205 8 4 8.2 4.5 | -18.4 -1.1 230 7 4 7.9 4.4
26000 -16.4 2.5 215 7 3 8.2 4.5 | -16.0 3.2 230 6 3 7.9 4.4
25000 -14.0 6.8 230 6 3 6.4 3.5 | -13.7 7.3 230 5 3 7.1 3.9
24000 -12.2 10.0 230 6 3 6.2 3.4 | -11.6 11.1 245 4 2 7.0 3.8
23000 -10.4 13.3 230 7 4 6.3 3.4 | -9.6 14.7 260 4 2 7.0 3.8
22000 -8.1 17.4 225 7 4 6.3 3.5 | -7.2 19.0 265 3 2 4.8 2.7
21000 -6.3 20.7 225 7 3 6.4 3.5 | -5.9 21.4 225 3 2 5.2 2.9
20000 -4.5 23.9 220 6 3 6.4 3.5 | -4.5 23.9 200 5 2 5.6 3.1
19500 -3.5 25.7 215 6 3 7.2 4.0 | -3.7 25.3 190 6 3 7.2 3.9
19000 -2.4 27.7 210 6 3 7.3 4.0 | -2.7 27.1 180 8 4 7.4 4.1
18500 -1.4 29.5 205 7 3 7.3 4.0 | -1.6 29.1 180 11 5 7.3 4.0
18000 -0.3 31.5 200 8 4 7.0 3.8 | -0.6 30.9 175 12 6 6.6 3.6
17500 0.7 33.3 195 9 5 7.0 3.9 | 0.3 32.5 175 13 7 6.7 3.7
17000 1.7 35.1 190 10 5 6.4 3.5 | 1.3 34.3 170 14 7 7.2 3.9
16500 2.6 36.7 190 11 6 6.3 3.5 | 2.3 36.1 170 15 8 7.3 4.0
16000 3.5 38.3 185 13 7 6.7 3.7 | 3.4 38.1 170 16 8 7.6 4.1
15500 4.5 40.1 180 13 7 7.5 4.1 | 4.5 40.1 165 17 9 8.2 4.5
15000 5.5 41.9 180 14 7 7.6 4.2 | 5.7 42.3 160 19 10 8.1 4.4
14500 6.6 43.9 175 13 7 8.9 4.9 | 7.0 44.6 160 19 10 9.7 5.3
14000 7.8 46.0 170 13 7 8.8 4.8 | 8.4 47.1 160 19 10 9.6 5.2
13500 9.1 48.4 165 12 6 9.0 5.0 | 9.8 49.6 160 19 10 9.7 5.3
13000 10.4 50.7 160 12 6 9.1 5.0 | 11.2 52.2 160 19 10 9.8 5.4
12500 11.7 53.1 155 12 6 9.3 5.1 | 12.7 54.9 160 19 10 9.6 5.3
12000 13.1 55.6 155 11 6 9.4 5.2 | 14.1 57.4 160 19 10 9.5 5.2
11500 14.4 57.9 150 11 6 9.5 5.2 | 15.5 59.9 160 19 10 9.5 5.2
11000 15.9 60.6 150 11 6 9.4 5.2 | 17.0 62.6 165 19 10 9.3 5.1
10500 17.3 63.1 145 11 6 6.5 3.6 | 18.4 65.1 165 19 10 7.6 4.1
10250 17.6 63.7 145 11 6 7.7 4.2 | 18.9 66.0 165 19 10 8.3 4.6
10000 18.5 65.3 145 11 6 12.0 6.6 | 19.6 67.3 165 19 10 11.0 6.0
9750 19.3 66.7 145 11 6 11.5 6.3 | 20.4 68.7 165 19 10 10.7 5.9
9500 20.1 68.2 145 11 6 9.2 5.1 | 21.2 70.2 165 18 9 9.1 5.0
9250 20.7 69.3 145 11 6 8.1 4.4 | 21.8 71.2 170 18 9 8.1 4.4
9000 21.5 70.7 145 11 6 10.5 5.8 | 22.5 72.5 170 18 9 9.5 5.2
8750 22.2 72.0 140 11 6 10.6 5.8 | 23.2 73.8 170 18 9 9.5 5.2
8500 23.0 73.4 140 11 6 9.8 5.4 | 23.9 75.0 170 18 9 9.4 5.2
8250 23.7 74.7 140 11 6 8.8 4.8 | 24.6 76.3 175 18 9 9.3 5.1
8000 24.4 75.9 140 11 5 10.0 5.5 | 25.3 77.5 175 18 9 9.4 5.2
7750 25.2 77.4 140 11 5 10.8 5.9 | 26.0 78.8 175 17 9 9.4 5.2
7500 26.0 78.8 140 10 5 10.2 5.6 | 26.7 80.1 180 17 9 9.5 5.2
7250 26.7 80.1 140 10 5 9.9 5.4 | 27.4 81.3 180 17 9 9.6 5.3
7000 27.4 81.3 140 10 5 10.1 5.5 | 28.1 82.6 180 17 9 9.6 5.2
6750 28.2 82.8 135 10 5 10.5 5.8 | 28.8 83.8 180 17 9 9.6 5.2
6500 29.0 84.2 135 10 5 10.5 5.8 | 29.6 85.3 185 17 9 10.0 5.5
6250 29.8 85.6 135 10 5 11.0 6.1 | 30.4 86.7 185 16 8 10.6 5.8
6000 30.6 87.1 135 9 5 9.1 5.0 | 31.1 88.0 185 16 8 9.7 5.3
5750 31.4 88.5 135 9 5 16.5 9.1 | 31.9 89.4 185 15 8 12.3 6.7
5500 33.3 91.9 135 9 4 35.0 19.2 | 33.1 91.6 185 14 7 20.0 11.0
________________________________________________________________________________
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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