762
UXUS97 KGJT 161307
SRGGJT
SOARING FORECAST
NATIONAL WEATHER SERVICE GRAND JUNCTION, COLORADO
607 AM MST FRIDAY, JANUARY 16, 2026
THIS FORECAST IS FOR FRIDAY, JANUARY 16, 2026:
IF THE TRIGGER TEMPERATURE OF 37.1 F/2.9 C IS REACHED...THEN
THERMAL SOARING INDEX....................... GOOD
MAXIMUM RATE OF LIFT........................ 509 FT/MIN (2.6 M/S)
MAXIMUM HEIGHT OF THERMALS.................. 12621 FT MSL (7015 FT AGL)
FORECAST MAXIMUM TEMPERATURE................... 46.0 F/8.2 C
TIME OF TRIGGER TEMPERATURE.................... 1015 MST
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................. 11014 FT MSL (5408 FT AGL)
THERMAL SOARING OUTLOOK FOR SATURDAY 01/17..... GOOD
WAVE SOARING INDEX............................. NOT AVAILABLE
REMARKS...
SUNRISE/SUNSET.................... 07:31:14 / 17:16:45 MST
TOTAL POSSIBLE SUNSHINE........... 9 HR 45 MIN 31 SEC (585 MIN 31 SEC)
ALTITUDE OF SUN AT 12:23:59 MST... 29.80 DEGREES
UPPER AIR DATA FROM RAWINSONDE OBSERVATION TAKEN ON 01/16/2026 AT 0500 MST
FREEZING LEVEL.................. ENTIRE AIRMASS BELOW 32 F / 0 C
CONVECTIVE CONDENSATION LEVEL... 18193 FT MSL (12587 FT AGL)
LIFTED CONDENSATION LEVEL....... 14765 FT MSL (9159 FT AGL)
LIFTED INDEX.................... +11.9
K INDEX......................... -9.4
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 -56.9 -70.4 340 49 25 -0.5 -0.3 M M M M M
45000 -57.6 -71.7 340 70 36 -0.5 -0.3 M M M M M
40000 -58.4 -73.1 360 89 46 -0.6 -0.3 M M M M M
38000 -58.1 -72.6 005 98 51 2.6 1.4 M M M M M
36000 -56.6 -69.9 005 107 55 2.6 1.4 M M M M M
34000 -54.5 -66.1 005 116 60 7.6 4.2 M M M M M
32000 -50.0 -58.0 005 114 59 7.5 4.1 M M M M M
30000 -45.5 -49.9 005 112 58 7.8 4.3 30.6 87.0 17.1 M M
29000 -43.2 -45.8 005 110 56 7.8 4.3 29.7 85.4 16.6 M M
28000 -40.8 -41.4 360 107 55 7.8 4.3 28.9 84.0 16.2 M M
27000 -38.5 -37.3 360 105 54 7.8 4.3 28.3 82.9 15.9 M M
26000 -36.2 -33.2 360 103 53 7.9 4.3 27.5 81.5 15.5 M M
25000 -33.8 -28.8 360 101 52 7.9 4.3 26.7 80.1 15.1 M M
24000 -31.5 -24.7 360 99 51 8.0 4.4 26.1 79.0 14.8 M M
23000 -29.5 -21.1 005 95 49 5.9 3.2 24.9 76.8 13.9 M M
22000 -27.8 -18.0 005 92 47 5.9 3.2 23.5 74.2 12.9 M M
21000 -26.0 -14.8 005 88 45 5.9 3.2 22.2 71.9 12.0 M M
20000 -24.3 -11.7 005 80 41 5.5 3.0 20.6 69.1 10.8 M M
19500 -23.1 -9.6 005 73 38 5.5 3.0 19.5 67.1 9.9 M M
19000 -22.3 -8.1 360 69 35 5.5 3.0 18.8 65.8 9.4 M M
18500 -21.4 -6.5 360 64 33 5.5 3.0 18.1 64.6 8.8 M M
18000 -20.6 -5.1 360 61 32 5.5 3.0 17.3 63.2 8.2 M M
17500 -19.8 -3.6 355 58 30 5.5 3.0 16.6 61.9 7.6 M M
17000 -19.0 -2.2 355 56 29 4.8 2.6 15.8 60.5 7.0 M M
16500 -18.3 -0.9 350 53 27 4.9 2.7 15.0 59.0 6.3 M M
16000 -17.7 0.1 350 51 26 3.7 2.1 14.1 57.4 5.5 M M
15500 -17.1 1.2 350 48 25 3.7 2.0 13.1 55.5 4.6 M M
15000 -16.6 2.1 350 46 24 4.1 2.2 12.1 53.7 3.7 M M
14500 -15.9 3.4 350 44 23 4.3 2.3 11.1 52.1 2.9 M M
14000 -15.3 4.5 345 42 22 4.6 2.5 10.2 50.4 2.1 M M
13500 -14.6 5.7 345 41 21 4.9 2.7 9.4 49.0 1.4 M M
13000 -13.8 7.2 345 40 20 4.4 2.4 8.7 47.6 0.7 M M
12500 -13.3 8.1 345 39 20 3.7 2.0 7.7 45.8 -0.2 500 2.5
12000 -12.7 9.1 345 38 19 3.7 2.0 6.7 44.1 -1.1 469 2.4
11500 -12.2 10.0 345 34 18 3.7 2.0 5.7 42.3 -2.1 438 2.2
11000 -11.6 11.1 345 31 16 4.3 2.3 4.8 40.6 -3.0 407 2.1
10500 -10.9 12.4 345 28 14 4.4 2.4 4.0 39.2 -3.8 370 1.9
10250 -10.5 13.1 350 27 14 6.6 3.6 3.6 38.5 -4.1 352 1.8
10000 -9.9 14.2 350 24 13 7.7 4.2 3.5 38.3 -4.3 327 1.7
9750 -9.5 14.9 350 23 12 6.2 3.4 3.2 37.8 -4.5 304 1.5
9500 -9.0 15.8 350 21 11 7.1 3.9 3.0 37.4 -4.8 282 1.4
9250 -8.5 16.7 355 20 10 4.9 2.7 2.7 36.9 -5.0 260 1.3
9000 -8.2 17.2 355 19 10 5.9 3.2 2.3 36.2 -5.5 244 1.2
8750 -7.6 18.3 355 18 9 8.8 4.8 2.2 35.9 -5.6 218 1.1
8500 -6.9 19.6 355 16 8 8.2 4.5 2.1 35.7 -5.7 192 1.0
8250 -6.4 20.5 360 14 7 7.0 3.8 1.9 35.5 -5.9 167 0.9
8000 -5.9 21.4 360 13 7 7.1 3.9 1.7 35.0 -6.2 146 0.7
7750 -5.3 22.5 360 11 6 8.6 4.7 1.6 34.8 -6.3 120 0.6
7500 -4.7 23.5 005 10 5 8.1 4.5 1.5 34.6 -6.4 94 0.5
7250 -4.1 24.6 005 9 5 8.1 4.5 1.3 34.4 -6.6 69 0.4
7000 -3.5 25.7 005 8 4 7.4 4.0 1.2 34.1 -6.8 44 0.2
6750 -3.0 26.6 005 7 4 6.3 3.4 1.0 33.7 -7.0 22 0.1
6500 -2.5 27.5 010 6 3 5.8 3.2 0.7 33.2 -7.3 1 0.0
6250 -2.1 28.2 010 5 3 5.4 3.0 0.4 32.6 -7.7 M M
6000 -1.7 28.9 015 4 2 5.6 3.1 0.0 32.1 -8.0 M M
5750 -1.5 29.3 025 2 1 -2.5 -1.4 -0.5 31.1 -8.6 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 * * * * * *
01/16/2026 AT 0800 MST | 01/16/2026 AT 1100 MST
|
CAPE... 0.0 LI... +8.8 | CAPE... 0.0 LI... +9.4
CINH... -0.2 K INDEX... -12.6 | CINH... -0.2 K INDEX... -9.9
|
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 -57.2 -71.0 320 49 25 1.1 0.6 | -57.5 -71.5 320 44 22 0.9 0.5
45000 -55.5 -67.9 310 58 30 1.2 0.7 | -56.3 -69.3 310 60 31 0.9 0.5
40000 -55.1 -67.2 325 77 40 0.2 0.1 | -56.2 -69.2 325 72 37 0.0 0.0
38000 -55.3 -67.5 325 81 42 -0.9 -0.5 | -56.2 -69.2 330 77 40 -0.4 -0.2
36000 -55.8 -68.4 330 75 39 -0.8 -0.5 | -56.5 -69.7 330 77 40 -0.4 -0.2
34000 -56.2 -69.2 335 70 36 3.2 1.8 | -56.5 -69.7 330 77 40 4.7 2.6
32000 -53.1 -63.6 335 72 37 5.1 2.8 | -52.8 -63.0 330 73 38 6.2 3.4
30000 -49.8 -57.6 340 74 38 8.9 4.9 | -48.9 -56.0 335 70 36 9.1 5.0
29000 -47.1 -52.8 335 74 38 9.0 4.9 | -46.2 -51.2 335 70 36 9.0 4.9
28000 -44.4 -47.9 335 74 38 9.0 4.9 | -43.5 -46.3 335 70 36 9.0 4.9
27000 -41.7 -43.1 330 74 38 9.1 5.0 | -40.9 -41.6 335 71 36 9.1 5.0
26000 -39.1 -38.4 330 73 38 8.5 4.7 | -38.4 -37.1 335 70 36 8.0 4.4
25000 -36.5 -33.7 330 72 37 8.5 4.7 | -36.0 -32.8 335 70 36 8.0 4.4
24000 -34.0 -29.2 330 71 36 8.6 4.7 | -33.6 -28.5 335 69 35 8.1 4.4
23000 -30.9 -23.6 330 69 35 8.2 4.5 | -31.3 -24.3 335 68 35 7.4 4.1
22000 -28.5 -19.3 330 67 35 8.2 4.5 | -28.5 -19.3 335 66 34 7.4 4.1
21000 -26.1 -15.0 335 66 34 7.4 4.0 | -26.3 -15.3 335 64 33 6.9 3.8
20000 -23.9 -11.0 335 63 33 7.2 4.0 | -24.3 -11.7 335 62 32 6.8 3.7
19500 -22.8 -9.0 335 62 32 7.2 4.0 | -23.3 -9.9 335 61 31 6.8 3.7
19000 -21.7 -7.1 335 61 32 7.2 4.0 | -22.3 -8.1 335 60 31 6.8 3.7
18500 -20.7 -5.3 335 60 31 6.8 3.7 | -21.3 -6.3 335 58 30 6.4 3.5
18000 -19.7 -3.5 340 59 30 6.6 3.6 | -20.4 -4.7 340 57 29 6.2 3.4
17500 -18.7 -1.7 340 57 29 6.5 3.6 | -19.4 -2.9 340 56 29 6.1 3.3
17000 -17.8 -0.0 340 56 29 5.9 3.2 | -18.6 -1.5 340 54 28 5.7 3.1
16500 -16.9 1.6 340 54 28 6.0 3.3 | -17.7 0.1 340 53 27 5.8 3.2
16000 -16.0 3.2 340 52 27 5.4 2.9 | -16.8 1.8 345 52 27 5.6 3.1
15500 -15.2 4.6 340 50 26 5.4 2.9 | -16.0 3.2 345 50 26 5.6 3.1
15000 -14.4 6.1 340 48 25 5.6 3.1 | -15.2 4.6 345 49 25 5.2 2.9
14500 -13.6 7.5 340 45 23 5.7 3.1 | -14.4 6.1 345 46 24 5.1 2.8
14000 -12.7 9.1 340 43 22 5.2 2.9 | -13.6 7.5 345 44 23 5.0 2.8
13500 -12.0 10.4 340 42 22 4.8 2.6 | -12.9 8.8 345 41 21 5.0 2.7
13000 -11.3 11.7 340 42 22 4.7 2.6 | -12.1 10.2 345 38 19 4.8 2.6
12500 -10.6 12.9 345 40 21 4.5 2.5 | -11.5 11.3 345 36 18 4.5 2.5
12000 -10.0 14.0 345 38 20 4.5 2.5 | -10.8 12.6 345 34 18 4.0 2.2
11500 -9.3 15.3 345 36 18 4.5 2.5 | -10.3 13.5 345 31 16 3.4 1.8
11000 -8.7 16.3 350 33 17 5.2 2.9 | -9.8 14.4 350 27 14 3.8 2.1
10500 -7.8 18.0 350 31 16 6.1 3.3 | -9.2 15.4 355 25 13 4.3 2.4
10250 -7.3 18.9 355 30 16 6.0 3.3 | -8.9 16.0 355 23 12 4.1 2.2
10000 -6.9 19.6 355 30 15 5.1 2.8 | -8.6 16.5 360 22 11 3.9 2.1
9750 -6.6 20.1 355 29 15 6.0 3.3 | -8.3 17.1 360 21 11 6.1 3.3
9500 -6.0 21.2 355 28 14 7.5 4.1 | -7.8 18.0 005 20 10 7.6 4.2
9250 -5.5 22.1 360 26 14 6.8 3.7 | -7.2 19.0 005 18 9 7.1 3.9
9000 -5.1 22.8 360 25 13 6.0 3.3 | -6.7 19.9 010 17 9 6.8 3.7
8750 -4.7 23.5 360 24 12 5.6 3.1 | -6.2 20.8 015 15 8 7.2 4.0
8500 -4.2 24.4 005 22 11 5.9 3.3 | -5.7 21.7 015 15 7 7.9 4.3
8250 -3.5 25.7 010 19 10 4.1 2.3 | -5.1 22.8 020 14 7 6.9 3.8
8000 -3.2 26.2 015 17 9 3.5 1.9 | -4.2 24.4 035 11 6 6.8 3.7
7750 -3.0 26.6 025 15 8 3.0 1.7 | -3.7 25.3 035 11 5 7.1 3.9
7500 -2.7 27.1 030 13 7 4.1 2.2 | -3.2 26.2 040 10 5 6.5 3.6
7250 -2.4 27.7 035 12 6 5.6 3.1 | -2.7 27.1 045 9 5 6.3 3.4
7000 -2.1 28.2 045 10 5 1.2 0.7 | -2.2 28.0 050 8 4 6.8 3.7
6750 -2.1 28.2 050 9 5 2.2 1.2 | -1.6 29.1 045 7 4 8.5 4.6
6500 -1.7 28.9 055 8 4 6.5 3.5 | -1.0 30.2 045 7 4 9.5 5.2
6250 -1.2 29.8 060 8 4 7.4 4.1 | -0.3 31.5 050 6 3 8.3 4.6
6000 -0.8 30.6 065 7 4 -0.7 -0.4 | 0.4 32.7 050 6 3 11.8 6.5
5750 -1.7 28.9 060 4 2 -22.3 -12.3 | 1.6 34.9 050 6 3 20.1 11.0
5500 -2.7 27.1 055 2 1 14.6 8.0 | 2.8 37.0 050 6 3 6.2 3.4
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
01/16/2026 AT 1400 MST | 01/16/2026 AT 1700 MST
|
CAPE... 0.0 LI... +8.5 | CAPE... 0.0 LI... +7.8
CINH... -0.2 K INDEX... -4.7 | CINH... 0.0 K INDEX... -0.2
|
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 -57.6 -71.7 320 44 23 0.4 0.2 | -56.8 -70.2 325 43 22 0.5 0.3
45000 -57.0 -70.6 310 60 31 0.4 0.2 | -56.0 -68.8 320 61 32 0.5 0.3
40000 -56.5 -69.7 325 66 34 0.3 0.2 | -55.6 -68.1 330 63 33 0.3 0.1
38000 -56.4 -69.5 330 70 36 0.3 0.2 | -55.4 -67.7 335 66 34 0.5 0.3
36000 -56.2 -69.2 330 74 38 0.3 0.2 | -55.0 -67.0 340 73 38 0.6 0.3
34000 -55.8 -68.4 330 78 40 4.6 2.5 | -54.7 -66.5 340 80 41 1.8 1.0
32000 -52.3 -62.1 330 75 38 5.9 3.2 | -51.9 -61.4 335 77 40 4.8 2.7
30000 -48.6 -55.5 335 72 37 9.0 4.9 | -49.0 -56.2 330 75 39 6.6 3.6
29000 -45.9 -50.6 335 72 37 8.9 4.9 | -46.6 -51.9 330 75 39 8.1 4.4
28000 -43.2 -45.8 335 72 37 8.9 4.9 | -44.2 -47.6 330 75 38 8.1 4.4
27000 -40.6 -41.1 335 71 37 9.1 5.0 | -41.1 -42.0 335 74 38 8.1 4.4
26000 -38.2 -36.8 335 70 36 7.8 4.3 | -38.8 -37.8 335 74 38 7.8 4.3
25000 -35.8 -32.4 335 69 36 7.8 4.3 | -36.4 -33.5 340 73 37 7.8 4.3
24000 -33.5 -28.3 335 68 35 7.9 4.3 | -34.1 -29.4 340 72 37 7.8 4.3
23000 -31.3 -24.3 335 66 34 7.1 3.9 | -31.8 -25.2 340 69 36 7.6 4.2
22000 -29.2 -20.6 335 63 32 7.1 3.9 | -29.5 -21.1 340 66 34 7.6 4.2
21000 -26.6 -15.9 335 60 31 6.6 3.6 | -27.2 -17.0 340 63 32 7.1 3.9
20000 -24.7 -12.5 330 58 30 6.4 3.5 | -25.3 -13.5 335 60 31 6.4 3.5
19500 -23.7 -10.7 330 57 29 6.4 3.5 | -24.3 -11.7 335 59 31 6.4 3.5
19000 -22.8 -9.0 330 56 29 6.4 3.5 | -23.4 -10.1 335 58 30 6.3 3.5
18500 -21.8 -7.2 330 55 28 6.1 3.4 | -22.4 -8.3 330 57 29 6.0 3.3
18000 -20.9 -5.6 330 54 28 5.9 3.2 | -21.6 -6.9 330 56 29 5.2 2.8
17500 -20.1 -4.2 330 53 27 5.9 3.2 | -20.9 -5.6 330 55 28 5.2 2.8
17000 -19.2 -2.6 330 53 27 5.4 3.0 | -20.1 -4.2 330 54 28 5.3 2.9
16500 -18.4 -1.1 335 52 27 5.5 3.0 | -19.3 -2.7 330 53 27 5.3 2.9
16000 -17.6 0.3 335 51 26 5.7 3.1 | -18.5 -1.3 335 52 27 5.6 3.0
15500 -16.7 1.9 335 50 26 5.7 3.1 | -17.6 0.3 335 51 26 5.6 3.1
15000 -15.9 3.4 340 49 25 5.8 3.2 | -16.8 1.8 335 50 26 5.7 3.1
14500 -15.0 5.0 340 47 24 5.8 3.2 | -15.9 3.4 335 47 24 5.7 3.1
14000 -14.1 6.6 340 45 23 5.4 2.9 | -15.1 4.8 335 45 23 5.9 3.2
13500 -13.4 7.9 340 41 21 4.8 2.6 | -14.1 6.6 335 42 22 6.2 3.4
13000 -12.7 9.1 340 37 19 4.9 2.7 | -13.2 8.2 335 38 20 6.2 3.4
12500 -11.9 10.6 345 35 18 5.0 2.7 | -12.3 9.9 335 36 18 5.9 3.3
12000 -11.2 11.8 345 33 17 4.7 2.6 | -11.4 11.5 340 34 17 5.8 3.2
11500 -10.6 12.9 345 30 15 4.3 2.3 | -10.6 12.9 340 30 16 5.2 2.9
11000 -9.9 14.2 345 27 14 4.1 2.3 | -9.8 14.4 340 27 14 5.2 2.9
10500 -9.4 15.1 350 23 12 4.0 2.2 | -9.1 15.6 340 23 12 5.1 2.8
10250 -9.1 15.6 350 21 11 3.8 2.1 | -8.7 16.3 340 21 11 5.1 2.8
10000 -8.8 16.2 355 19 10 4.7 2.6 | -8.3 17.1 340 19 10 5.4 3.0
9750 -8.4 16.9 355 17 9 6.7 3.7 | -7.9 17.8 340 17 9 6.9 3.8
9500 -7.9 17.8 355 16 8 7.2 4.0 | -7.3 18.9 340 15 8 7.7 4.2
9250 -7.3 18.9 360 14 7 7.4 4.1 | -6.2 20.8 345 12 6 8.8 4.9
9000 -6.8 19.8 005 12 6 8.3 4.6 | -5.5 22.1 345 10 5 8.3 4.6
8750 -6.1 21.0 005 11 6 8.1 4.4 | -5.0 23.0 350 9 5 7.2 4.0
8500 -5.6 21.9 010 10 5 7.5 4.1 | -4.4 24.1 355 8 4 7.5 4.1
8250 -5.0 23.0 015 9 5 8.0 4.4 | -3.8 25.2 360 7 4 7.1 3.9
8000 -4.4 24.1 015 9 4 8.0 4.4 | -3.3 26.1 360 6 3 8.2 4.5
7750 -3.1 26.4 020 8 4 9.5 5.2 | -2.6 27.3 005 5 3 9.0 5.0
7500 -2.4 27.7 020 7 4 9.2 5.0 | -2.0 28.4 015 4 2 7.9 4.3
7250 -1.7 28.9 025 7 4 8.6 4.7 | -1.4 29.5 020 4 2 6.9 3.8
7000 -1.1 30.0 025 7 4 10.5 5.8 | -0.9 30.4 025 3 2 8.6 4.7
6750 -0.2 31.6 025 7 3 11.0 6.0 | -0.2 31.6 045 2 1 9.7 5.3
6500 0.5 32.9 025 6 3 9.7 5.3 | 0.5 32.9 055 2 1 8.7 4.8
6250 1.3 34.3 030 6 3 9.5 5.2 | 1.2 34.2 070 2 1 9.9 5.4
6000 2.0 35.6 030 6 3 11.8 6.5 | 1.9 35.4 085 2 1 6.0 3.3
5750 3.1 37.6 030 6 3 18.8 10.3 | 2.0 35.6 105 2 1 -2.6 -1.4
5500 4.5 40.1 030 5 3 12.7 7.0 | 2.1 35.8 110 2 1 15.8 8.7
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.
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