934
UXUS97 KBOU 131319
SRGBOU
SOARING FORECAST
NATIONAL WEATHER SERVICE DENVER/BOULDER, COLORADO
0716 MDT FRIDAY, MARCH 13, 2026
THIS FORECAST IS FOR FRIDAY, MARCH 13, 2026:
IF THE TRIGGER TEMPERATURE OF 59.2 F/15.1 C IS REACHED...THEN
THERMAL SOARING INDEX....................... GOOD
MAXIMUM RATE OF LIFT........................ 623 FT/MIN (3.2 M/S)
MAXIMUM HEIGHT OF THERMALS.................. 14741 FT MSL (9381 FT AGL)
FORECAST MAXIMUM TEMPERATURE................... 72.0 F/22.7 C
TIME OF TRIGGER TEMPERATURE.................... 0945 MDT
TIME OF OVERDEVELOPMENT........................ NONE
MIDDLE/HIGH CLOUDS DURING SOARING WINDOW....... OVERCAST THIN HIGH
SURFACE WINDS DURING SOARING WINDOW............ 20 MPH OR LESS
HEIGHT OF THE -3 THERMAL INDEX................. 12228 FT MSL (6868 FT AGL)
THERMAL SOARING OUTLOOK FOR SATURDAY 03/14..... 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)................ NEITHER
POTENTIAL HEIGHT OF WAVE....................... 14453 FT MSL (9093 FT AGL)
WAVE SOARING OUTLOOK FOR SATURDAY 03/14........ GOOD
REMARKS...
SUNRISE/SUNSET.................... 07:13:28 / 19:04:12 MDT
TOTAL POSSIBLE SUNSHINE........... 11 HR 50 MIN 44 SEC (710 MIN 44 SEC)
ALTITUDE OF SUN AT 13:08:50 MDT... 47.49 DEGREES
UPPER AIR DATA FROM NUMERICAL MODEL FORECAST VALID ON 03/13/2026 AT 0600 MDT
FREEZING LEVEL.................. 11178 FT MSL (5818 FT AGL)
CONVECTIVE CONDENSATION LEVEL... 18322 FT MSL (12962 FT AGL)
LIFTED CONDENSATION LEVEL....... 17229 FT MSL (11870 FT AGL)
LIFTED INDEX.................... +2.8
K INDEX......................... +1.6
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 -64.5 -84.1 300 59 30 -3.5 -1.9 M M M M M
45000 -70.0 -94.0 295 80 41 0.5 0.3 M M M M M
40000 -64.4 -83.9 295 84 43 3.7 2.1 M M M M M
38000 -60.4 -76.7 295 82 42 8.3 4.5 M M M M M
36000 -55.5 -67.9 290 77 40 8.3 4.5 M M M M M
34000 -50.6 -59.1 290 72 37 8.1 4.4 M M M M M
32000 -45.1 -49.2 290 66 34 8.1 4.4 M M M M M
30000 -40.3 -40.5 290 61 31 7.9 4.4 35.3 95.5 9.8 M M
29000 -38.0 -36.4 290 59 30 7.9 4.4 34.5 94.1 9.4 M M
28000 -35.6 -32.1 290 57 30 7.9 4.4 33.9 93.0 9.0 M M
27000 -33.2 -27.8 290 56 29 7.9 4.3 33.3 91.9 8.6 M M
26000 -30.9 -23.6 295 54 28 7.9 4.3 32.4 90.4 8.1 M M
25000 -28.5 -19.3 295 52 27 7.9 4.3 31.8 89.2 7.6 M M
24000 -26.2 -15.2 295 51 26 7.6 4.2 31.2 88.1 7.2 M M
23000 -23.9 -11.0 300 48 25 7.4 4.1 30.2 86.4 6.5 M M
22000 -21.7 -7.1 300 46 24 7.4 4.1 29.4 84.9 5.9 M M
21000 -19.5 -3.1 305 43 22 7.0 3.8 28.6 83.5 5.3 M M
20000 -17.4 0.7 305 40 21 7.0 3.9 27.6 81.6 4.5 M M
19500 -16.4 2.5 305 39 20 7.0 3.9 27.1 80.8 4.1 M M
19000 -14.8 5.4 310 37 19 7.0 3.9 26.4 79.6 3.5 M M
18500 -13.8 7.2 310 35 18 6.9 3.8 26.0 78.7 3.1 M M
18000 -12.8 9.0 310 34 17 6.9 3.8 25.5 77.8 2.7 M M
17500 -11.7 10.9 315 33 17 7.1 3.9 25.0 77.0 2.3 M M
17000 -10.7 12.7 315 34 18 7.2 3.9 24.5 76.2 1.9 M M
16500 -9.6 14.7 315 35 18 7.1 3.9 24.1 75.4 1.5 M M
16000 -8.6 16.5 315 36 19 6.9 3.8 23.7 74.6 1.1 M M
15500 -7.5 18.5 315 37 19 7.0 3.8 23.2 73.7 0.7 M M
15000 -6.5 20.3 310 38 19 6.4 3.5 22.7 72.8 0.2 M M
14500 -5.6 21.9 310 39 20 6.5 3.6 22.1 71.8 -0.3 698 3.5
14000 -4.7 23.5 310 40 20 6.1 3.3 21.6 70.8 -0.8 655 3.3
13500 -3.8 25.2 310 41 21 6.0 3.3 20.9 69.7 -1.4 614 3.1
13000 -2.9 26.8 305 42 22 5.7 3.1 20.3 68.6 -2.0 573 2.9
12500 -2.1 28.2 305 42 22 5.6 3.1 19.7 67.4 -2.7 533 2.7
12000 -1.3 29.7 300 43 22 5.4 3.0 19.0 66.2 -3.3 494 2.5
11500 -0.5 31.1 300 43 22 5.3 2.9 18.3 64.9 -4.0 457 2.3
11000 0.3 32.5 295 43 22 5.1 2.8 17.6 63.6 -4.7 419 2.1
10500 1.0 33.8 295 42 22 4.7 2.6 16.8 62.2 -5.5 382 1.9
10250 1.4 34.5 295 41 21 6.3 3.4 16.4 61.6 -5.9 364 1.8
10000 1.9 35.4 295 40 21 7.3 4.0 16.2 61.2 -6.1 341 1.7
9750 2.4 36.3 290 39 20 6.5 3.5 16.0 60.8 -6.4 319 1.6
9500 2.9 37.2 290 37 19 6.8 3.7 15.7 60.3 -6.6 297 1.5
9250 3.3 37.9 290 35 18 6.4 3.5 15.5 59.9 -6.9 275 1.4
9000 3.8 38.8 290 34 18 7.4 4.1 15.3 59.5 -7.1 253 1.3
8750 4.4 39.9 290 32 17 8.6 4.7 15.1 59.3 -7.3 227 1.2
8500 5.1 41.2 290 30 15 8.7 4.8 15.1 59.1 -7.4 201 1.0
8250 5.7 42.3 290 28 14 8.3 4.5 15.0 58.9 -7.5 174 0.9
8000 6.3 43.3 290 26 13 7.9 4.3 14.8 58.7 -7.7 149 0.8
7750 6.9 44.4 290 24 12 8.7 4.8 14.7 58.5 -7.8 123 0.6
7500 7.6 45.7 290 22 11 9.3 5.1 14.7 58.4 -7.9 96 0.5
7250 8.3 46.9 285 19 10 8.4 4.6 14.6 58.3 -7.9 68 0.3
7000 8.9 48.0 285 17 9 7.5 4.1 14.5 58.0 -8.1 43 0.2
6750 9.5 49.1 285 15 8 8.9 4.9 14.3 57.8 -8.3 18 0.1
6500 10.1 50.2 280 13 7 8.7 4.7 14.3 57.7 -8.3 M M
6250 10.7 51.3 275 11 5 6.2 3.4 14.1 57.4 -8.5 M M
6000 11.1 52.0 270 8 4 5.3 2.9 13.8 56.8 -8.9 M M
5750 11.5 52.7 260 6 3 6.7 3.7 13.5 56.3 -9.2 M M
5500 11.7 53.1 245 5 3 -9.3 -5.1 12.9 55.2 -9.8 M M
* * * * * * NUMERICAL WEATHER PREDICTION MODEL FORECAST DATA VALID * * * * * *
03/13/2026 AT 0900 MDT | 03/13/2026 AT 1200 MDT
|
CAPE... 0.0 LI... +5.3 | CAPE... 0.0 LI... +5.0
CINH... -1.6 K INDEX... +0.8 | CINH... -0.2 K INDEX... +3.8
|
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 -65.1 -85.2 300 65 34 -3.0 -1.6 | -64.8 -84.6 300 54 28 -2.7 -1.5
45000 -69.8 -93.6 290 83 43 1.0 0.5 | -69.0 -92.2 295 86 44 -0.0 -0.0
40000 -64.2 -83.6 295 81 42 3.7 2.0 | -64.4 -83.9 300 83 43 3.0 1.7
38000 -60.3 -76.5 295 78 40 8.0 4.4 | -60.8 -77.4 300 79 41 8.1 4.5
36000 -55.5 -67.9 295 75 38 8.0 4.4 | -55.9 -68.6 295 74 38 8.1 4.5
34000 -50.7 -59.3 295 70 36 8.1 4.4 | -50.4 -58.7 290 68 35 8.2 4.5
32000 -45.2 -49.4 290 63 33 8.1 4.4 | -45.5 -49.9 290 62 32 8.2 4.5
30000 -40.4 -40.7 290 58 30 7.9 4.4 | -40.7 -41.3 285 56 29 7.9 4.3
29000 -38.0 -36.4 290 56 29 7.9 4.4 | -38.3 -36.9 290 54 28 7.9 4.3
28000 -35.6 -32.1 290 54 28 7.9 4.4 | -36.0 -32.8 290 52 27 7.9 4.3
27000 -33.3 -27.9 290 52 27 7.4 4.1 | -33.6 -28.5 290 49 25 7.3 4.0
26000 -31.1 -24.0 295 49 25 7.5 4.1 | -31.4 -24.5 295 47 24 7.4 4.0
25000 -28.8 -19.8 295 47 24 7.5 4.1 | -29.2 -20.6 295 44 23 7.4 4.1
24000 -26.6 -15.9 300 45 23 7.4 4.0 | -27.0 -16.6 295 41 21 7.4 4.1
23000 -24.4 -11.9 300 42 21 7.3 4.0 | -24.8 -12.6 300 39 20 7.5 4.1
22000 -22.2 -8.0 300 39 20 7.3 4.0 | -22.6 -8.7 300 37 19 7.5 4.1
21000 -20.0 -4.0 305 36 19 7.1 3.9 | -20.4 -4.7 300 35 18 7.2 4.0
20000 -17.9 -0.2 310 33 17 7.1 3.9 | -18.2 -0.8 300 33 17 7.2 4.0
19500 -16.9 1.6 310 32 17 7.1 3.9 | -17.1 1.2 300 32 16 7.2 4.0
19000 -15.8 3.6 310 31 16 7.1 3.9 | -15.5 4.1 300 30 16 7.2 4.0
18500 -14.2 6.4 315 30 15 7.5 4.1 | -14.4 6.1 300 29 15 7.0 3.9
18000 -13.1 8.4 315 29 15 7.5 4.1 | -13.4 7.9 300 29 15 7.1 3.9
17500 -11.9 10.6 320 29 15 7.6 4.2 | -12.3 9.9 300 28 15 7.0 3.9
17000 -10.8 12.6 320 30 15 7.6 4.2 | -11.3 11.7 305 28 15 7.0 3.9
16500 -9.7 14.5 320 31 16 7.5 4.1 | -10.3 13.5 305 28 15 6.9 3.8
16000 -8.6 16.5 320 32 16 7.4 4.1 | -9.3 15.3 305 29 15 6.6 3.6
15500 -7.5 18.5 320 33 17 7.5 4.1 | -8.3 17.1 305 29 15 6.6 3.6
15000 -6.5 20.3 320 34 17 6.4 3.5 | -7.3 18.9 305 29 15 6.5 3.6
14500 -5.5 22.1 320 35 18 6.6 3.6 | -6.3 20.7 300 30 15 6.6 3.6
14000 -4.5 23.9 315 36 19 6.2 3.4 | -5.4 22.3 300 30 16 6.6 3.6
13500 -3.6 25.5 315 38 19 6.2 3.4 | -4.4 24.1 300 30 16 6.6 3.6
13000 -2.7 27.1 310 39 20 5.8 3.2 | -3.4 25.9 295 31 16 6.4 3.5
12500 -1.9 28.6 310 40 20 5.6 3.1 | -2.5 27.5 295 30 16 6.3 3.4
12000 -1.1 30.0 305 41 21 5.4 3.0 | -1.6 29.1 295 30 15 6.8 3.7
11500 -0.3 31.5 305 41 21 5.3 2.9 | -0.5 31.1 295 29 15 7.2 3.9
11000 0.4 32.7 300 41 21 4.5 2.5 | 0.5 32.9 290 29 15 6.7 3.7
10500 1.0 33.8 300 40 21 3.6 2.0 | 1.5 34.7 290 29 15 5.7 3.1
10250 1.3 34.3 300 40 21 5.6 3.0 | 1.9 35.4 290 29 15 9.0 4.9
10000 1.8 35.2 295 39 20 6.8 3.7 | 2.7 36.9 290 29 15 9.6 5.3
9750 2.2 36.0 295 38 19 5.6 3.1 | 3.3 37.9 290 28 15 6.6 3.6
9500 2.6 36.7 295 36 19 6.2 3.4 | 3.8 38.8 285 27 14 7.6 4.2
9250 3.1 37.6 295 35 18 5.1 2.8 | 4.3 39.7 285 26 13 6.5 3.6
9000 3.4 38.1 290 34 17 6.3 3.4 | 4.8 40.6 285 24 12 7.8 4.3
8750 4.0 39.2 290 32 16 8.8 4.8 | 5.5 41.9 285 23 12 9.8 5.4
8500 4.7 40.5 290 30 15 9.1 5.0 | 6.2 43.2 280 22 11 9.6 5.3
8250 5.4 41.7 290 28 15 8.3 4.6 | 6.9 44.4 280 21 11 9.2 5.1
8000 5.9 42.6 285 26 13 7.7 4.2 | 7.6 45.7 280 20 10 9.1 5.0
7750 6.5 43.7 285 24 12 8.8 4.8 | 8.3 46.9 280 20 10 10.0 5.5
7500 7.2 45.0 285 23 12 9.3 5.1 | 9.1 48.4 280 19 10 10.6 5.8
7250 7.9 46.2 280 21 11 8.1 4.5 | 9.8 49.6 280 19 10 9.1 5.0
7000 8.4 47.1 275 19 10 7.1 3.9 | 10.4 50.7 280 18 9 7.8 4.3
6750 9.0 48.2 270 17 9 9.0 4.9 | 11.1 52.0 280 18 9 10.9 6.0
6500 9.7 49.5 265 16 8 8.6 4.7 | 12.0 53.6 280 17 9 12.0 6.6
6250 10.2 50.4 260 15 7 6.0 3.3 | 12.8 55.0 280 16 8 10.3 5.7
6000 10.7 51.3 250 13 7 6.0 3.3 | 13.6 56.5 280 16 8 10.0 5.5
5750 11.1 52.0 245 11 6 5.2 2.9 | 14.3 57.7 275 15 8 10.3 5.7
5500 11.4 52.5 235 10 5 0.9 0.5 | 15.3 59.5 280 14 7 16.1 8.8
03/13/2026 AT 1500 MDT | 03/13/2026 AT 1800 MDT
|
CAPE... 0.0 LI... +3.5 | CAPE... 0.0 LI... +2.9
CINH... -0.0 K INDEX... +8.3 | CINH... -0.4 K INDEX... +8.4
|
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 -65.8 -86.4 300 54 28 -2.0 -1.1 | -64.8 -84.6 300 60 31 -2.0 -1.1
45000 -68.8 -91.8 295 83 43 0.5 0.3 | -67.8 -90.0 295 81 42 0.9 0.5
40000 -64.4 -83.9 295 80 41 2.9 1.6 | -63.8 -82.8 290 72 37 2.6 1.4
38000 -60.5 -76.9 295 77 40 8.6 4.7 | -59.9 -75.8 285 69 35 8.7 4.8
36000 -55.4 -67.7 295 73 37 8.6 4.7 | -54.7 -66.5 285 66 34 8.7 4.8
34000 -49.7 -57.5 290 68 35 8.0 4.4 | -49.0 -56.2 285 63 32 8.0 4.4
32000 -44.9 -48.8 290 63 32 8.1 4.4 | -44.2 -47.6 285 61 31 8.0 4.4
30000 -40.2 -40.4 290 58 30 7.4 4.1 | -39.6 -39.3 290 58 30 7.1 3.9
29000 -38.0 -36.4 290 56 29 7.4 4.1 | -37.5 -35.5 290 55 29 7.1 3.9
28000 -35.8 -32.4 290 54 28 7.4 4.1 | -35.3 -31.5 290 53 28 7.2 3.9
27000 -33.6 -28.5 295 52 27 7.1 3.9 | -33.2 -27.8 295 52 27 6.7 3.7
26000 -31.4 -24.5 295 50 25 7.1 3.9 | -31.2 -24.2 295 50 26 6.8 3.7
25000 -29.3 -20.7 295 47 24 7.1 3.9 | -29.2 -20.6 300 49 25 6.8 3.7
24000 -27.2 -17.0 300 45 23 7.1 3.9 | -27.2 -17.0 300 47 24 6.8 3.8
23000 -25.1 -13.2 300 43 22 7.2 3.9 | -25.1 -13.2 305 46 24 6.9 3.8
22000 -22.9 -9.2 300 41 21 7.2 3.9 | -23.0 -9.4 305 44 23 6.9 3.8
21000 -20.8 -5.4 305 39 20 7.4 4.1 | -21.0 -5.8 305 42 22 6.9 3.8
20000 -18.6 -1.5 305 37 19 7.4 4.1 | -18.9 -2.0 305 40 21 7.0 3.8
19500 -16.9 1.6 305 37 19 7.4 4.1 | -17.9 -0.2 310 39 20 7.0 3.8
19000 -15.8 3.6 305 36 19 7.4 4.1 | -16.3 2.7 310 38 19 7.0 3.8
18500 -14.7 5.5 305 36 18 7.5 4.1 | -15.3 4.5 310 37 19 7.2 4.0
18000 -13.6 7.5 305 36 18 7.5 4.1 | -14.2 6.4 310 36 19 7.2 4.0
17500 -12.5 9.5 305 35 18 7.3 4.0 | -13.1 8.4 310 36 18 7.2 4.0
17000 -11.4 11.5 305 35 18 7.2 4.0 | -12.1 10.2 310 36 18 7.2 4.0
16500 -10.3 13.5 305 35 18 7.1 3.9 | -11.0 12.2 310 35 18 7.4 4.0
16000 -9.3 15.3 305 35 18 6.8 3.7 | -9.9 14.2 310 35 18 7.8 4.3
15500 -8.3 17.1 305 35 18 6.8 3.7 | -8.7 16.3 310 36 18 7.8 4.3
15000 -7.3 18.9 305 35 18 6.9 3.8 | -7.6 18.3 310 36 18 7.6 4.2
14500 -6.3 20.7 300 35 18 6.8 3.8 | -6.4 20.5 305 35 18 7.6 4.2
14000 -5.3 22.5 300 35 18 7.3 4.0 | -5.3 22.5 305 35 18 7.7 4.2
13500 -4.2 24.4 300 35 18 7.4 4.0 | -4.2 24.4 300 35 18 7.7 4.2
13000 -3.1 26.4 295 35 18 7.0 3.8 | -3.0 26.6 300 35 18 7.8 4.3
12500 -2.1 28.2 295 35 18 6.9 3.8 | -1.9 28.6 300 34 18 7.8 4.3
12000 -1.1 30.0 290 35 18 7.6 4.2 | -0.7 30.7 295 34 17 8.1 4.4
11500 0.1 32.2 290 35 18 8.0 4.4 | 0.5 32.9 290 33 17 8.2 4.5
11000 1.3 34.3 285 34 18 7.5 4.1 | 1.7 35.1 290 33 17 7.7 4.2
10500 2.4 36.3 285 32 17 6.4 3.5 | 2.8 37.0 285 32 17 6.6 3.6
10250 2.9 37.2 285 32 16 10.6 5.8 | 3.4 38.1 285 32 16 10.6 5.8
10000 3.9 39.0 285 31 16 12.1 6.6 | 4.3 39.7 285 31 16 11.8 6.5
9750 4.6 40.3 285 30 16 8.9 4.9 | 5.0 41.0 285 30 15 8.6 4.7
9500 5.3 41.5 285 30 15 10.1 5.5 | 5.7 42.3 285 29 15 9.7 5.3
9250 6.0 42.8 285 29 15 8.7 4.8 | 6.4 43.5 285 28 15 8.6 4.7
9000 6.7 44.1 285 29 15 9.1 5.0 | 7.0 44.6 285 28 14 9.1 5.0
8750 7.4 45.3 285 28 15 10.5 5.7 | 7.8 46.0 285 27 14 10.1 5.5
8500 8.2 46.8 285 28 14 10.2 5.6 | 8.5 47.3 285 26 13 9.9 5.4
8250 9.0 48.2 285 27 14 9.8 5.4 | 9.2 48.6 285 25 13 9.6 5.3
8000 9.7 49.5 285 27 14 9.4 5.1 | 9.9 49.8 285 25 13 9.4 5.1
7750 10.4 50.7 285 27 14 9.9 5.5 | 10.6 51.1 285 24 12 9.8 5.4
7500 11.1 52.0 285 26 14 10.3 5.6 | 11.4 52.5 285 23 12 10.3 5.6
7250 11.9 53.4 285 26 13 9.3 5.1 | 12.1 53.8 285 22 11 9.2 5.0
7000 12.5 54.5 285 26 13 8.6 4.7 | 12.8 55.0 285 22 11 8.3 4.5
6750 13.2 55.8 285 25 13 10.7 5.9 | 13.4 56.1 285 21 11 10.3 5.6
6500 14.1 57.4 285 24 13 11.5 6.3 | 14.3 57.7 285 20 10 10.9 6.0
6250 14.9 58.8 285 24 12 10.4 5.7 | 15.0 59.0 285 19 10 9.6 5.3
6000 15.7 60.3 285 23 12 10.3 5.7 | 15.7 60.3 285 18 9 9.3 5.1
5750 16.5 61.7 285 22 11 10.0 5.5 | 16.4 61.5 285 17 9 8.9 4.9
5500 17.3 63.1 285 20 10 14.1 7.7 | 17.0 62.6 285 15 8 8.2 4.5
________________________________________________________________________________
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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