599
UXUS97 KGJT 151307
SRGGJT
SOARING FORECAST
NATIONAL WEATHER SERVICE GRAND JUNCTION, COLORADO
707 AM MDT SUNDAY, MARCH 15, 2026
THIS FORECAST IS FOR SUNDAY, MARCH 15, 2026:
IF THE TRIGGER TEMPERATURE OF 43.1 F/6.2 C IS REACHED...THEN
THERMAL SOARING INDEX....................... GOOD
MAXIMUM RATE OF LIFT........................ 407 FT/MIN (2.1 M/S)
MAXIMUM HEIGHT OF THERMALS.................. 11650 FT MSL (6044 FT AGL)
FORECAST MAXIMUM TEMPERATURE................... 51.0 F/11.0 C
TIME OF TRIGGER TEMPERATURE.................... 1245 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................. 10364 FT MSL (4758 FT AGL)
THERMAL SOARING OUTLOOK FOR MONDAY 03/16....... GOOD
WAVE SOARING INDEX............................. NOT AVAILABLE
REMARKS...
SUNRISE/SUNSET.................... 07:24:50 / 19:21:02 MDT
TOTAL POSSIBLE SUNSHINE........... 11 HR 56 MIN 12 SEC (716 MIN 12 SEC)
ALTITUDE OF SUN AT 13:22:56 MDT... 48.64 DEGREES
UPPER AIR DATA FROM RAWINSONDE OBSERVATION TAKEN ON 03/15/2026 AT 0600 MDT
FREEZING LEVEL.................. 5744 FT MSL (138 FT AGL)
ADDITIONAL FREEZING LEVEL....... 6255 FT MSL (649 FT AGL)
CONVECTIVE CONDENSATION LEVEL... 25242 FT MSL (19636 FT AGL)
LIFTED CONDENSATION LEVEL....... 16944 FT MSL (11338 FT AGL)
LIFTED INDEX.................... +16.8
K INDEX......................... +0.6
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 -62.8 -81.0 335 66 34 0.9 0.5 M M M M M
45000 -61.5 -78.7 335 86 44 0.4 0.2 M M M M M
40000 -61.0 -77.8 345 137 71 0.3 0.2 M M M M M
38000 -57.3 -71.1 345 141 73 7.9 4.3 M M M M M
36000 -52.6 -62.7 340 136 70 7.9 4.3 M M M M M
34000 -47.9 -54.2 340 126 65 7.6 4.2 M M M M M
32000 -43.3 -45.9 335 109 56 7.6 4.2 M M M M M
30000 -38.6 -37.5 335 96 49 8.1 4.5 37.7 99.8 20.4 M M
29000 -36.2 -33.2 330 92 47 8.1 4.4 36.9 98.5 20.1 M M
28000 -33.8 -28.8 330 89 46 8.1 4.4 36.4 97.4 19.9 M M
27000 -31.4 -24.5 330 86 44 8.2 4.5 35.8 96.5 19.7 M M
26000 -28.9 -20.0 330 83 43 8.2 4.5 35.1 95.3 19.4 M M
25000 -26.5 -15.7 330 80 41 8.3 4.5 34.6 94.3 19.2 M M
24000 -24.0 -11.2 330 78 40 7.9 4.3 34.2 93.5 19.0 M M
23000 -21.8 -7.2 330 75 39 7.3 4.0 33.2 91.7 18.4 M M
22000 -19.6 -3.3 330 72 37 7.4 4.0 32.3 90.1 17.8 M M
21000 -17.2 1.0 330 69 35 4.4 2.4 31.0 87.7 16.9 M M
20000 -15.8 3.6 330 65 34 4.7 2.6 29.1 84.4 15.5 M M
19500 -15.1 4.8 330 64 33 4.7 2.6 28.2 82.8 14.8 M M
19000 -14.4 6.1 330 62 32 4.9 2.7 27.4 81.3 14.2 M M
18500 -13.9 7.0 330 60 31 2.6 1.4 26.4 79.6 13.4 M M
18000 -13.5 7.7 330 58 30 2.5 1.4 25.1 77.3 12.4 M M
17500 -13.1 8.4 330 56 29 2.8 1.5 23.9 75.0 11.3 M M
17000 -12.7 9.1 330 55 28 3.4 1.9 22.8 73.0 10.4 M M
16500 -12.1 10.2 330 53 27 3.3 1.8 21.7 71.1 9.5 M M
16000 -11.6 11.1 330 51 26 4.5 2.5 20.7 69.3 8.7 M M
15500 -10.9 12.4 330 49 25 4.4 2.4 19.8 67.7 7.9 M M
15000 -10.3 13.5 330 47 24 4.2 2.3 18.9 66.1 7.1 M M
14500 -9.7 14.5 330 44 23 4.1 2.3 18.0 64.4 6.3 M M
14000 -9.1 15.6 330 42 21 3.4 1.9 17.1 62.7 5.5 M M
13500 -8.7 16.3 330 39 20 2.8 1.6 15.9 60.7 4.5 M M
13000 -8.2 17.2 325 36 18 2.1 1.2 14.8 58.7 3.5 M M
12500 -8.1 17.4 325 33 17 1.2 0.6 13.4 56.1 2.2 M M
12000 -7.9 17.8 320 30 15 1.1 0.6 12.0 53.7 0.9 M M
11500 -7.7 18.1 315 26 13 1.2 0.7 10.6 51.1 -0.3 402 2.0
11000 -7.4 18.7 310 22 12 1.7 1.0 9.3 48.7 -1.6 381 1.9
10500 -7.0 19.4 305 19 10 2.1 1.1 8.1 46.6 -2.6 353 1.8
10250 -6.8 19.8 305 17 9 4.0 2.2 7.5 45.6 -3.2 340 1.7
10000 -6.4 20.5 300 15 8 5.2 2.9 7.2 44.9 -3.5 320 1.6
9750 -6.1 21.0 300 13 7 4.2 2.3 6.8 44.2 -3.9 302 1.5
9500 -5.7 21.7 300 12 6 4.7 2.6 6.3 43.4 -4.3 284 1.4
9250 -5.4 22.3 295 10 5 4.0 2.2 5.9 42.7 -4.7 266 1.4
9000 -5.1 22.8 295 9 4 4.9 2.7 5.5 41.9 -5.1 250 1.3
8750 -4.6 23.7 290 7 4 6.3 3.5 5.2 41.4 -5.4 228 1.2
8500 -4.1 24.6 285 5 3 5.9 3.2 4.9 40.8 -5.7 207 1.1
8250 -3.7 25.3 280 4 2 6.4 3.5 4.6 40.3 -5.9 186 0.9
8000 -3.2 26.2 280 3 1 6.5 3.6 4.4 39.9 -6.2 164 0.8
7750 -2.7 27.1 270 2 1 6.1 3.4 4.1 39.4 -6.5 142 0.7
7500 -2.2 28.0 210 1 0 6.3 3.4 3.8 38.9 -6.8 120 0.6
7250 -1.7 28.9 160 1 1 6.3 3.4 3.6 38.4 -7.0 99 0.5
7000 -1.3 29.7 160 2 1 6.5 3.6 3.3 38.0 -7.3 77 0.4
6750 -0.8 30.6 150 2 1 6.9 3.8 3.1 37.6 -7.6 55 0.3
6500 -0.3 31.5 140 3 1 4.8 2.6 2.8 37.1 -7.8 33 0.2
6250 -0.1 31.8 145 3 2 1.6 0.9 2.3 36.1 -8.4 19 0.1
6000 0.1 32.2 145 4 2 6.7 3.7 1.8 35.2 -8.9 5 0.0
5750 0.8 33.4 140 4 2 5.2 2.9 1.7 35.0 -9.0 M M
5500 M M M M M M M M M M M M
5250 M M M M M M M M M M M M
5000 M M M M M M M M M M M M
* * * * * * NUMERICAL WEATHER PREDICTION MODEL FORECAST DATA VALID * * * * * *
03/15/2026 AT 0900 MDT | 03/15/2026 AT 1200 MDT
|
CAPE... 0.0 LI... +15.5 | CAPE... +1.3 LI... +14.5
CINH... -0.1 K INDEX... -22.7 | CINH... -0.0 K INDEX... -13.5
|
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 -56.6 -69.9 315 47 24 1.3 0.7 | -57.1 -70.8 320 52 27 1.1 0.6
45000 -54.7 -66.5 320 57 29 1.4 0.8 | -55.4 -67.7 325 68 35 1.3 0.7
40000 -55.4 -67.7 315 82 42 -0.6 -0.3 | -55.7 -68.3 325 86 44 -0.2 -0.1
38000 -55.5 -67.9 320 96 49 0.5 0.3 | -55.6 -68.1 330 98 50 0.7 0.4
36000 -55.2 -67.4 330 115 59 0.5 0.3 | -55.1 -67.2 335 117 60 0.7 0.4
34000 -54.7 -66.5 340 135 70 5.2 2.9 | -54.4 -65.9 340 136 70 7.4 4.0
32000 -50.3 -58.5 335 123 64 7.3 4.0 | -49.4 -56.9 340 130 67 8.3 4.6
30000 -45.9 -50.6 330 113 58 8.3 4.5 | -44.4 -47.9 335 124 64 7.9 4.3
29000 -43.5 -46.3 325 109 56 8.3 4.6 | -42.1 -43.8 335 117 60 7.7 4.2
28000 -41.0 -41.8 325 105 54 8.3 4.6 | -39.9 -39.8 330 110 57 7.7 4.2
27000 -38.5 -37.3 320 102 52 8.3 4.6 | -37.6 -35.7 330 104 53 7.7 4.2
26000 -36.1 -33.0 320 100 52 7.9 4.3 | -35.3 -31.5 325 100 52 7.6 4.2
25000 -33.7 -28.7 320 99 51 7.9 4.3 | -33.0 -27.4 325 98 50 7.6 4.2
24000 -30.8 -23.4 320 97 50 7.9 4.3 | -30.2 -22.4 325 95 49 7.6 4.2
23000 -28.5 -19.3 320 96 49 7.5 4.1 | -28.2 -18.8 320 93 48 6.7 3.7
22000 -26.3 -15.3 315 95 49 7.6 4.1 | -26.2 -15.2 320 90 46 6.7 3.7
21000 -24.0 -11.2 315 93 48 7.3 4.0 | -24.2 -11.6 320 88 45 6.5 3.6
20000 -21.9 -7.4 315 93 48 7.0 3.8 | -22.3 -8.1 320 85 44 6.2 3.4
19500 -20.9 -5.6 315 92 47 7.0 3.8 | -21.4 -6.5 320 84 43 6.2 3.4
19000 -19.8 -3.6 315 92 47 6.9 3.8 | -20.4 -4.7 320 83 43 6.2 3.4
18500 -18.8 -1.8 315 91 47 6.7 3.7 | -19.5 -3.1 320 82 42 6.0 3.3
18000 -18.0 -0.4 315 90 46 4.9 2.7 | -18.7 -1.7 320 81 42 4.9 2.7
17500 -17.2 1.0 315 89 46 5.1 2.8 | -18.0 -0.4 320 80 41 5.1 2.8
17000 -16.5 2.3 315 87 45 3.3 1.8 | -17.3 0.9 315 78 40 3.8 2.1
16500 -16.1 3.0 315 84 43 3.0 1.7 | -16.7 1.9 320 76 39 3.7 2.0
16000 -15.6 3.9 315 81 42 1.8 1.0 | -16.2 2.8 320 73 38 2.2 1.2
15500 -15.5 4.1 315 77 40 0.3 0.2 | -16.0 3.2 320 69 35 1.0 0.5
15000 -15.5 4.1 315 72 37 0.1 0.0 | -15.9 3.4 320 64 33 0.5 0.3
14500 -15.6 3.9 315 66 34 -1.4 -0.8 | -15.9 3.4 320 59 30 -0.8 -0.5
14000 -15.8 3.6 320 60 31 -1.4 -0.8 | -16.0 3.2 320 54 28 -0.8 -0.4
13500 -15.9 3.4 320 54 28 0.1 0.1 | -16.2 2.8 320 47 24 -1.1 -0.6
13000 -15.9 3.4 320 49 25 -0.2 -0.1 | -16.3 2.7 325 41 21 -1.1 -0.6
12500 -15.7 3.7 320 43 22 2.5 1.4 | -16.3 2.7 325 34 18 1.6 0.9
12000 -15.4 4.3 325 39 20 2.2 1.2 | -16.1 3.0 330 28 14 1.5 0.8
11500 -14.9 5.2 325 34 18 4.2 2.3 | -15.6 3.9 330 22 12 5.2 2.9
11000 -14.3 6.3 330 31 16 4.2 2.3 | -14.9 5.2 335 17 9 5.5 3.0
10500 -13.5 7.7 335 27 14 6.3 3.4 | -13.8 7.2 340 15 8 8.2 4.5
10250 -13.1 8.4 335 26 13 6.3 3.5 | -13.2 8.2 340 13 7 8.0 4.4
10000 -12.6 9.3 340 24 12 5.5 3.0 | -12.6 9.3 340 12 6 7.8 4.3
9750 -12.2 10.0 340 23 12 6.9 3.8 | -12.0 10.4 340 12 6 8.9 4.9
9500 -11.6 11.1 345 22 11 8.9 4.9 | -11.3 11.7 345 12 6 10.0 5.5
9250 -11.0 12.2 345 20 10 8.4 4.6 | -10.5 13.1 345 11 6 9.6 5.3
9000 -10.3 13.5 350 19 10 8.4 4.6 | -9.8 14.4 345 11 6 10.7 5.9
8750 -9.7 14.5 350 17 9 8.8 4.9 | -9.0 15.8 345 10 5 10.0 5.5
8500 -9.0 15.8 350 17 9 9.5 5.2 | -7.6 18.3 345 10 5 9.2 5.1
8250 -7.7 18.1 355 16 8 8.3 4.6 | -6.9 19.6 345 10 5 9.0 4.9
8000 -7.0 19.4 355 15 7 9.2 5.1 | -6.3 20.7 345 9 5 10.1 5.5
7750 -6.3 20.7 355 14 7 10.6 5.8 | -5.4 22.3 345 9 5 10.9 6.0
7500 -5.5 22.1 355 14 7 9.2 5.1 | -4.7 23.5 345 9 5 9.5 5.2
7250 -4.9 23.2 355 13 7 7.8 4.3 | -4.0 24.8 345 9 5 8.0 4.4
7000 -4.3 24.3 350 13 7 9.8 5.4 | -3.4 25.9 345 9 4 10.8 5.9
6750 -3.4 25.9 355 12 6 10.9 6.0 | -2.4 27.7 350 9 4 12.0 6.6
6500 -2.7 27.1 355 12 6 9.9 5.4 | -1.6 29.1 345 8 4 10.7 5.9
6250 -1.9 28.6 350 11 6 9.9 5.4 | -0.8 30.6 345 8 4 10.2 5.6
6000 -1.2 29.8 350 10 5 10.3 5.6 | -0.0 32.0 345 8 4 13.1 7.2
5750 -0.3 31.5 350 9 5 13.5 7.4 | 1.3 34.3 345 7 4 23.3 12.8
5500 1.0 33.8 350 8 4 22.1 12.1 | 3.2 37.8 345 7 4 24.1 13.2
5250 M M M M M M M | M M M M M M M
5000 M M M M M M M | M M M M M M M
03/15/2026 AT 1500 MDT | 03/15/2026 AT 1800 MDT
|
CAPE... 0.0 LI... +14.5 | CAPE... 0.0 LI... +13.5
CINH... -0.1 K INDEX... -14.0 | CINH... -0.2 K INDEX... -13.8
|
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 -58.1 -72.6 325 58 30 1.2 0.7 | -59.7 -75.5 330 61 32 1.0 0.5
45000 -56.3 -69.3 330 78 40 1.5 0.8 | -58.2 -72.8 335 85 44 -0.6 -0.3
40000 -58.3 -72.9 330 101 52 -1.4 -0.8 | -60.8 -77.4 335 118 61 -1.8 -1.0
38000 -57.7 -71.9 335 110 56 3.7 2.0 | -59.1 -74.4 340 124 64 6.6 3.6
36000 -55.5 -67.9 340 118 61 3.6 2.0 | -55.2 -67.4 345 125 64 6.6 3.6
34000 -53.0 -63.4 345 125 65 8.6 4.7 | -51.0 -59.8 345 126 65 8.6 4.7
32000 -48.2 -54.8 340 123 64 8.0 4.4 | -45.9 -50.6 345 123 63 8.5 4.7
30000 -43.3 -45.9 340 121 62 8.3 4.5 | -40.8 -41.4 345 120 62 7.6 4.2
29000 -40.8 -41.4 335 118 61 8.3 4.6 | -38.5 -37.3 340 117 60 7.7 4.2
28000 -38.3 -36.9 335 115 59 8.3 4.6 | -36.2 -33.2 340 115 59 7.7 4.2
27000 -35.8 -32.4 335 113 58 8.4 4.6 | -33.4 -28.1 340 112 57 7.0 3.9
26000 -32.9 -27.2 335 109 56 7.7 4.2 | -31.3 -24.3 340 107 55 6.8 3.7
25000 -30.6 -23.1 330 106 55 7.7 4.2 | -29.3 -20.7 340 102 52 6.8 3.7
24000 -28.3 -18.9 330 103 53 7.5 4.1 | -27.3 -17.1 335 97 50 6.7 3.7
23000 -26.3 -15.3 330 100 52 6.9 3.8 | -25.3 -13.5 335 93 48 6.5 3.6
22000 -24.2 -11.6 330 97 50 6.9 3.8 | -23.4 -10.1 335 90 46 6.5 3.6
21000 -22.1 -7.8 330 94 49 6.0 3.3 | -21.5 -6.7 335 86 44 5.8 3.2
20000 -20.6 -5.1 330 89 46 5.3 2.9 | -19.8 -3.6 335 82 42 5.5 3.0
19500 -19.8 -3.6 330 87 45 5.3 2.9 | -19.0 -2.2 335 80 41 5.5 3.0
19000 -19.0 -2.2 325 84 43 5.3 2.9 | -18.1 -0.6 330 78 40 5.5 3.0
18500 -18.2 -0.8 325 82 42 4.8 2.6 | -17.3 0.9 330 76 39 4.9 2.7
18000 -17.6 0.3 325 79 41 3.5 1.9 | -16.7 1.9 330 73 38 4.1 2.2
17500 -17.1 1.2 325 77 40 3.6 2.0 | -16.1 3.0 330 71 36 4.2 2.3
17000 -16.6 2.1 325 74 38 2.6 1.5 | -15.6 3.9 330 68 35 2.5 1.4
16500 -16.2 2.8 320 71 36 2.6 1.5 | -15.2 4.6 330 65 33 2.7 1.5
16000 -15.8 3.6 320 68 35 1.4 0.8 | -14.8 5.4 325 62 32 1.8 1.0
15500 -15.7 3.7 320 63 33 0.6 0.3 | -14.6 5.7 325 58 30 1.5 0.8
15000 -15.6 3.9 320 59 30 0.2 0.1 | -14.4 6.1 325 54 28 1.1 0.6
14500 -15.7 3.7 320 54 28 -0.6 -0.3 | -14.3 6.3 320 50 26 0.6 0.3
14000 -15.8 3.6 320 48 25 -0.4 -0.2 | -14.2 6.4 320 45 23 1.0 0.6
13500 -15.7 3.7 320 42 22 1.1 0.6 | -13.9 7.0 315 41 21 2.5 1.4
13000 -15.5 4.1 320 35 18 1.2 0.7 | -13.5 7.7 315 36 19 2.8 1.5
12500 -15.1 4.8 320 29 15 4.2 2.3 | -12.9 8.8 315 32 16 5.0 2.7
12000 -14.5 5.9 320 23 12 4.2 2.3 | -12.2 10.0 315 27 14 5.2 2.9
11500 -13.7 7.3 325 19 10 6.7 3.7 | -11.2 11.8 315 23 12 7.1 3.9
11000 -12.7 9.1 325 16 8 6.8 3.8 | -10.1 13.8 320 20 10 7.1 3.9
10500 -11.6 11.1 330 14 7 8.1 4.4 | -9.0 15.8 320 17 9 7.4 4.0
10250 -11.0 12.2 330 13 7 8.4 4.6 | -8.5 16.7 320 15 8 7.6 4.2
10000 -10.4 13.3 330 12 6 7.1 3.9 | -7.9 17.8 325 14 7 6.6 3.6
9750 -9.8 14.4 330 12 6 8.2 4.5 | -7.4 18.7 325 13 7 7.6 4.2
9500 -9.1 15.6 330 12 6 10.4 5.7 | -6.8 19.8 325 12 6 9.4 5.2
9250 -8.4 16.9 330 11 6 9.8 5.4 | -6.1 21.0 325 11 6 8.9 4.9
9000 -6.9 19.6 330 11 5 9.7 5.3 | -5.4 22.3 325 10 5 8.8 4.8
8750 -6.2 20.8 330 10 5 10.1 5.5 | -4.1 24.6 325 9 5 9.2 5.0
8500 -5.4 22.3 330 10 5 9.6 5.3 | -3.4 25.9 330 8 4 8.8 4.8
8250 -4.7 23.5 330 10 5 8.4 4.6 | -2.8 27.0 330 8 4 7.7 4.2
8000 -4.1 24.6 330 10 5 10.1 5.5 | -2.2 28.0 325 7 4 9.5 5.2
7750 -3.2 26.2 330 9 5 11.6 6.3 | -1.4 29.5 330 7 3 11.0 6.1
7500 -2.4 27.7 330 9 5 9.3 5.1 | -0.6 30.9 330 6 3 9.1 5.0
7250 -1.8 28.8 330 9 5 7.0 3.8 | -0.0 32.0 330 6 3 7.2 4.0
7000 -1.2 29.8 325 9 4 11.1 6.1 | 0.6 33.1 325 6 3 10.7 5.9
6750 -0.2 31.6 330 8 4 12.7 7.0 | 1.5 34.7 330 5 3 12.1 6.6
6500 0.6 33.1 330 8 4 10.3 5.7 | 2.3 36.1 330 5 3 9.7 5.3
6250 1.4 34.5 325 8 4 9.9 5.4 | 3.1 37.6 330 5 2 9.8 5.4
6000 2.2 36.0 325 8 4 13.2 7.2 | 3.8 38.8 325 4 2 10.5 5.8
5750 3.5 38.3 330 7 4 24.4 13.4 | 4.7 40.5 330 4 2 14.7 8.1
5500 5.5 41.9 325 7 4 22.8 12.5 | 6.0 42.8 330 4 2 20.4 11.2
5250 M M M M M M M | M M M M M M M
5000 M M M M M M M | M M M M M M M
________________________________________________________________________________
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 AT WALKER FIELD IN GRAND
JUNCTION, COLORADO AT
NORTH LATITUDE: 39 DEG 07 MIN 00.001 SEC
WEST LONGITUDE: 108 DEG 31 MIN 59.998 SEC
ELEVATION: 4839 FEET (1475 METERS)
AND MAY NOT BE REPRESENTATIVE OF OTHER AREAS ALONG THE WESTERN SLOPE OF
COLORADO. 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