Soaring Guidance
Issued by NWS Grand Junction, CO
Issued by NWS Grand Junction, CO
118
UXUS97 KGJT 121306
SRGGJT
Soaring Forecast
National Weather Service Grand Junction, Colorado
606 AM MST Wednesday, February 12, 2025
This forecast is for Wednesday, February 12, 2025:
If the trigger temperature of 26.9 F/-2.9 C is reached...then
Thermal Soaring Index....................... Good
Maximum rate of lift........................ 755 ft/min (3.8 m/s)
Maximum height of thermals.................. 13870 ft MSL (9031 ft AGL)
Forecast maximum temperature................... 34.0 F/1.6 C
Time of trigger temperature.................... 1045 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................. 10631 ft MSL (5792 ft AGL)
Thermal soaring outlook for Thursday 02/13..... Good
Wave Soaring Index............................. Not available
Remarks...
Sunrise/Sunset.................... 07:08:35 / 17:48:06 MST
Total possible sunshine........... 10 hr 39 min 31 sec (639 min 31 sec)
Altitude of sun at 12:28:21 MST... 37.05 degrees
Upper air data from rawinsonde observation taken on 02/12/2025 at 0500 MST
Freezing level.................. Entire airmass below 32 F / 0 C
Convective condensation level... 12301 ft MSL (7462 ft AGL)
Lifted condensation level....... 13252 ft MSL (8413 ft AGL)
Lifted index.................... +7.4
K index......................... -21.2
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 -53.7 -64.7 265 46 24 2.9 1.6 115.4 239.8 64.6 M M
45000 -46.5 -51.7 270 55 28 2.7 1.5 102.8 217.1 61.3 M M
40000 -46.7 -52.1 270 49 25 4.2 2.3 78.8 173.9 50.0 M M
38000 -46.1 -51.0 270 44 23 6.6 3.6 70.7 159.3 45.9 M M
36000 -44.3 -47.7 280 57 29 -5.0 -2.8 63.6 146.6 42.5 M M
34000 -45.1 -49.2 270 45 23 5.0 2.7 53.9 129.1 36.8 M M
32000 -44.3 -47.7 270 56 29 -9.6 -5.3 46.8 116.3 32.7 M M
30000 -46.6 -51.9 275 57 29 -2.6 -1.4 35.5 95.9 25.2 M M
29000 -46.9 -52.4 275 52 27 0.1 0.1 31.2 88.1 22.4 M M
28000 -46.6 -51.9 275 53 27 1.8 1.0 27.6 81.7 20.0 M M
27000 -47.5 -53.5 280 53 27 -7.3 -4.0 22.6 72.7 16.4 M M
26000 -48.9 -56.0 275 54 28 6.2 3.4 16.9 62.4 12.2 M M
25000 -47.1 -52.8 275 53 27 6.2 3.4 15.6 60.0 11.3 M M
24000 -45.2 -49.4 270 52 27 6.2 3.4 14.2 57.5 10.4 M M
23000 -43.3 -45.9 280 46 24 6.3 3.4 12.8 55.1 9.4 M M
22000 -41.2 -42.2 275 47 24 8.3 4.5 11.8 53.3 8.7 M M
21000 -38.7 -37.7 280 45 23 8.3 4.5 11.3 52.3 8.4 M M
20000 -36.2 -33.2 275 44 23 8.2 4.5 10.7 51.3 8.0 M M
19500 -34.4 -29.9 280 46 24 7.1 3.9 10.3 50.5 7.7 M M
19000 -33.2 -27.8 280 45 23 9.3 5.1 10.0 50.0 7.5 M M
18500 -31.8 -25.2 285 44 22 9.1 5.0 9.9 49.8 7.5 M M
18000 -30.5 -22.9 285 44 22 9.5 5.2 9.8 49.6 7.4 M M
17500 -29.3 -20.7 285 43 22 5.7 3.1 9.4 48.8 7.1 M M
17000 -28.4 -19.1 285 40 21 3.8 2.1 8.7 47.7 6.6 M M
16500 -28.2 -18.8 275 37 19 -1.5 -0.8 7.4 45.3 5.4 M M
16000 -27.9 -18.2 270 35 18 7.1 3.9 6.0 42.8 4.3 M M
15500 -27.0 -16.6 280 36 18 6.3 3.5 5.4 41.7 3.8 M M
15000 -26.0 -14.8 280 30 15 5.9 3.2 4.8 40.6 3.3 M M
14500 -25.1 -13.2 270 24 12 -0.7 -0.4 4.2 39.5 2.7 M M
14000 -26.1 -15.0 265 19 10 -2.2 -1.2 1.5 34.7 0.3 M M
13500 -26.2 -15.2 255 15 8 2.5 1.4 -0.2 31.7 -1.2 744 3.8
13000 -25.1 -13.2 250 15 8 8.2 4.5 -0.6 30.8 -1.7 699 3.5
12500 -23.9 -11.0 250 14 7 8.1 4.4 -0.9 30.3 -2.0 648 3.3
12000 -22.7 -8.9 260 10 5 8.1 4.4 -1.2 29.8 -2.2 597 3.0
11500 -21.5 -6.7 265 11 6 8.1 4.4 -1.5 29.3 -2.5 546 2.8
11000 -20.3 -4.5 285 8 4 8.0 4.4 -1.8 28.8 -2.8 495 2.5
10500 -19.1 -2.4 285 8 4 8.0 4.4 -2.0 28.4 -3.1 444 2.3
10250 -18.5 -1.3 305 9 5 8.0 4.4 -2.2 28.1 -3.2 419 2.1
10000 -17.9 -0.2 315 10 5 8.1 4.4 -2.3 27.9 -3.3 394 2.0
9750 -17.3 0.9 315 10 5 7.9 4.3 -2.4 27.6 -3.5 368 1.9
9500 -16.7 1.9 315 9 5 8.6 4.7 -2.6 27.4 -3.6 343 1.7
9250 -16.0 3.2 305 9 5 9.3 5.1 -2.6 27.3 -3.7 315 1.6
9000 -15.4 4.3 290 10 5 9.1 5.0 -2.7 27.2 -3.7 287 1.5
8750 -14.7 5.5 295 10 5 9.2 5.0 -2.7 27.1 -3.8 259 1.3
8500 -14.0 6.8 305 11 6 9.1 5.0 -2.8 27.0 -3.9 231 1.2
8250 -13.3 8.1 305 10 5 9.1 5.0 -2.8 26.9 -3.9 203 1.0
8000 -12.6 9.3 280 11 5 9.1 5.0 -2.9 26.9 -4.0 175 0.9
7750 -11.9 10.6 280 12 6 9.2 5.0 -2.9 26.8 -4.0 147 0.7
7500 -11.2 11.8 285 14 7 9.1 5.0 -3.0 26.7 -4.1 119 0.6
7250 -10.5 13.1 290 13 7 9.2 5.1 -3.0 26.6 -4.2 91 0.5
7000 -9.8 14.4 300 12 6 10.0 5.5 -3.0 26.5 -4.2 62 0.3
6750 -9.1 15.6 300 11 6 10.3 5.7 -3.0 26.6 -4.2 32 0.2
6500 -8.4 16.9 300 11 6 8.1 4.4 -3.0 26.6 -4.2 4 0.0
6250 -7.9 17.8 300 13 6 6.5 3.5 -3.2 26.2 -4.5 M M
6000 -7.3 18.9 305 14 7 7.4 4.0 -3.5 25.8 -4.7 M M
5750 -6.9 19.6 305 15 8 2.1 1.1 -3.8 25.2 -5.0 M M
5500 -7.0 19.4 295 17 9 -3.0 -1.6 -4.6 23.7 -5.9 M M
5250 -7.1 19.2 295 14 7 0.7 0.4 -5.5 22.1 -6.7 M M
5000 -6.9 19.6 285 9 5 4.5 2.5 -6.0 21.2 -7.3 M M
* * * * * * Numerical weather prediction model forecast data valid * * * * * *
02/12/2025 at 0800 MST | 02/12/2025 at 1100 MST
|
CAPE... 0.0 LI... +8.4 | CAPE... 0.0 LI... +7.6
CINH... -0.2 K Index... -12.0 | CINH... -0.2 K Index... -11.3
|
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 -51.5 -60.7 275 38 20 1.8 1.0 | -51.4 -60.5 275 41 21 1.8 1.0
45000 -48.8 -55.8 270 48 25 1.8 1.0 | -48.7 -55.7 280 49 25 1.8 1.0
40000 -45.5 -49.9 275 52 27 2.3 1.3 | -46.2 -51.2 275 55 29 1.6 0.9
38000 -44.1 -47.4 275 53 27 2.3 1.3 | -45.2 -49.4 275 58 30 1.7 0.9
36000 -44.5 -48.1 280 55 28 -1.2 -0.7 | -45.5 -49.9 280 59 31 -0.9 -0.5
34000 -45.2 -49.4 280 57 29 -1.2 -0.7 | -46.0 -50.8 280 60 31 -0.9 -0.5
32000 -46.3 -51.3 285 58 30 -2.8 -1.6 | -46.9 -52.4 285 61 32 -2.5 -1.4
30000 -48.0 -54.4 285 59 30 -2.8 -1.5 | -48.4 -55.1 285 63 32 -2.5 -1.4
29000 -48.8 -55.8 285 59 30 -2.8 -1.5 | -49.2 -56.6 285 64 33 -2.1 -1.1
28000 -48.9 -56.0 285 56 29 0.2 0.1 | -49.0 -56.2 285 63 32 1.2 0.6
27000 -48.9 -56.0 285 52 27 0.2 0.1 | -48.7 -55.7 280 61 32 1.1 0.6
26000 -48.8 -55.8 285 48 25 0.4 0.2 | -48.3 -54.9 280 60 31 1.3 0.7
25000 -48.0 -54.4 285 45 23 6.1 3.4 | -47.4 -53.3 280 58 30 5.5 3.0
24000 -46.2 -51.2 285 44 22 6.1 3.3 | -45.7 -50.3 280 54 28 5.6 3.1
23000 -44.3 -47.7 285 42 21 6.2 3.4 | -44.0 -47.2 280 51 26 5.6 3.1
22000 -41.7 -43.1 285 40 21 7.8 4.3 | -41.6 -42.9 280 47 24 7.1 3.9
21000 -39.4 -38.9 285 40 21 7.8 4.3 | -39.5 -39.1 285 44 23 7.1 3.9
20000 -37.0 -34.6 290 40 21 8.0 4.4 | -37.3 -35.1 285 41 21 7.6 4.2
19500 -35.8 -32.4 290 40 21 8.1 4.4 | -36.2 -33.2 285 40 21 7.8 4.3
19000 -34.6 -30.3 290 40 20 8.1 4.4 | -35.0 -31.0 285 40 20 7.8 4.3
18500 -33.4 -28.1 290 39 20 8.1 4.4 | -33.9 -29.0 285 39 20 7.8 4.3
18000 -32.2 -26.0 290 39 20 8.1 4.5 | -32.7 -26.9 285 39 20 7.8 4.3
17500 -31.0 -23.8 290 39 20 6.8 3.7 | -31.5 -24.7 285 38 20 7.4 4.0
17000 -30.1 -22.2 290 38 19 6.3 3.4 | -30.5 -22.9 285 37 19 7.2 4.0
16500 -29.1 -20.4 285 37 19 5.9 3.3 | -29.4 -20.9 285 37 19 6.9 3.8
16000 -28.3 -18.9 285 36 18 5.2 2.8 | -28.4 -19.1 285 36 19 6.4 3.5
15500 -27.6 -17.7 285 34 18 5.2 2.8 | -27.5 -17.5 285 35 18 6.2 3.4
15000 -26.8 -16.2 285 33 17 4.8 2.6 | -26.7 -16.1 285 34 17 4.7 2.6
14500 -26.1 -15.0 285 32 16 4.9 2.7 | -26.0 -14.8 285 32 17 4.8 2.6
14000 -25.4 -13.7 285 30 15 4.3 2.4 | -25.3 -13.5 285 31 16 4.2 2.3
13500 -24.8 -12.6 285 28 14 4.4 2.4 | -24.7 -12.5 280 29 15 4.1 2.3
13000 -24.1 -11.4 285 26 13 3.9 2.2 | -23.9 -11.0 280 27 14 5.4 3.0
12500 -23.6 -10.5 280 24 12 3.9 2.1 | -23.2 -9.8 275 25 13 5.3 2.9
12000 -22.9 -9.2 280 22 11 4.7 2.6 | -22.4 -8.3 275 24 12 5.3 2.9
11500 -22.2 -8.0 275 20 10 4.5 2.5 | -21.6 -6.9 270 21 11 5.3 2.9
11000 -21.4 -6.5 275 17 9 6.7 3.7 | -20.7 -5.3 265 19 10 6.0 3.3
10500 -20.5 -4.9 270 15 8 6.4 3.5 | -19.9 -3.8 265 17 9 5.8 3.2
10250 -20.0 -4.0 270 14 7 5.6 3.1 | -19.5 -3.1 260 16 8 5.3 2.9
10000 -19.6 -3.3 270 14 7 4.7 2.6 | -19.1 -2.4 260 16 8 4.7 2.6
9750 -19.2 -2.6 275 13 7 7.3 4.0 | -18.7 -1.7 260 15 8 8.4 4.6
9500 -18.6 -1.5 275 11 6 8.6 4.7 | -17.9 -0.2 260 13 7 9.2 5.1
9250 -18.0 -0.4 275 10 5 6.9 3.8 | -17.4 0.7 260 12 6 6.6 3.6
9000 -17.5 0.5 280 9 5 6.9 3.8 | -16.9 1.6 260 12 6 6.4 3.5
8750 -17.0 1.4 285 8 4 6.8 3.7 | -16.4 2.5 265 11 6 8.4 4.6
8500 -16.0 3.2 285 7 4 7.5 4.1 | -15.6 3.9 260 10 5 9.5 5.2
8250 -15.4 4.3 290 7 4 7.0 3.9 | -15.0 5.0 265 9 5 8.0 4.4
8000 -14.9 5.2 295 7 3 8.4 4.6 | -13.8 7.2 265 8 4 7.8 4.3
7750 -14.2 6.4 295 7 3 8.7 4.8 | -13.2 8.2 270 8 4 9.0 4.9
7500 -13.6 7.5 295 6 3 7.8 4.3 | -12.4 9.7 270 8 4 11.3 6.2
7250 -13.0 8.6 295 6 3 7.5 4.1 | -11.6 11.1 270 7 4 8.2 4.5
7000 -12.5 9.5 295 7 4 7.6 4.1 | -11.1 12.0 270 7 4 7.7 4.2
6750 -11.8 10.8 290 7 4 8.7 4.8 | -10.4 13.3 270 7 4 11.1 6.1
6500 -11.2 11.8 290 6 3 8.8 4.8 | -9.5 14.9 270 6 3 11.2 6.1
6250 -10.5 13.1 290 6 3 9.3 5.1 | -8.7 16.3 275 6 3 10.8 5.9
6000 -9.8 14.4 280 7 3 8.0 4.4 | -8.0 17.6 280 6 3 8.5 4.6
5750 -9.3 15.3 280 6 3 6.5 3.6 | -7.3 18.9 275 6 3 12.1 6.7
5500 -8.4 16.9 275 4 2 24.9 13.7 | -5.1 22.8 280 6 3 57.1 31.3
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
02/12/2025 at 1400 MST | 02/12/2025 at 1700 MST
|
CAPE... 0.0 LI... +5.7 | CAPE... 0.0 LI... +4.1
CINH... -0.2 K Index... -5.0 | CINH... -0.3 K Index... -3.0
|
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 -52.0 -61.6 275 42 22 2.1 1.1 | -52.6 -62.7 280 43 22 1.7 0.9
45000 -48.7 -55.7 280 46 24 2.1 1.1 | -50.0 -58.0 285 51 26 1.7 0.9
40000 -46.4 -51.5 280 57 29 1.5 0.8 | -48.4 -55.1 295 56 29 0.9 0.5
38000 -45.5 -49.9 280 62 32 1.5 0.8 | -47.8 -54.0 295 58 30 1.0 0.5
36000 -45.9 -50.6 285 63 33 -1.2 -0.7 | -47.7 -53.9 305 64 33 0.0 0.0
34000 -46.7 -52.1 290 64 33 -1.2 -0.7 | -47.7 -53.9 310 71 37 0.0 0.0
32000 -47.4 -53.3 290 64 33 -1.2 -0.6 | -47.3 -53.1 310 74 38 1.6 0.9
30000 -48.1 -54.6 285 64 33 -1.2 -0.6 | -46.3 -51.3 310 73 38 1.6 0.9
29000 -48.4 -55.1 285 64 33 -0.9 -0.5 | -45.9 -50.6 310 73 38 1.7 0.9
28000 -48.4 -55.1 285 63 32 0.3 0.2 | -45.3 -49.5 310 71 36 1.8 1.0
27000 -48.3 -54.9 285 61 32 0.3 0.2 | -44.8 -48.6 310 68 35 1.8 1.0
26000 -48.2 -54.8 280 60 31 0.4 0.2 | -44.3 -47.7 305 65 34 1.8 1.0
25000 -47.5 -53.5 280 58 30 5.1 2.8 | -43.7 -46.7 305 62 32 2.3 1.2
24000 -45.9 -50.6 280 57 29 5.2 2.9 | -43.0 -45.4 300 59 30 2.3 1.3
23000 -44.3 -47.7 280 55 28 5.3 2.9 | -42.3 -44.1 295 56 29 2.3 1.3
22000 -42.5 -44.5 280 53 27 7.2 3.9 | -40.8 -41.4 290 53 27 5.1 2.8
21000 -39.8 -39.6 280 49 25 7.2 4.0 | -39.3 -38.7 290 52 27 5.1 2.8
20000 -37.6 -35.7 280 45 23 7.3 4.0 | -37.7 -35.9 285 50 26 6.2 3.4
19500 -36.5 -33.7 280 44 23 7.3 4.0 | -36.7 -34.1 285 49 25 6.5 3.6
19000 -35.4 -31.7 280 43 22 7.3 4.0 | -35.8 -32.4 285 48 25 6.5 3.6
18500 -34.3 -29.7 280 42 21 7.3 4.0 | -34.8 -30.6 285 47 24 6.5 3.6
18000 -33.2 -27.8 280 40 21 7.3 4.0 | -33.8 -28.8 285 46 24 6.5 3.6
17500 -32.1 -25.8 275 39 20 7.1 3.9 | -32.8 -27.0 280 45 23 6.9 3.8
17000 -31.1 -24.0 275 38 20 7.1 3.9 | -31.8 -25.2 280 43 22 6.9 3.8
16500 -30.0 -22.0 275 37 19 6.6 3.6 | -30.8 -23.4 280 42 21 6.9 3.8
16000 -29.1 -20.4 275 36 19 6.1 3.3 | -29.7 -21.5 280 39 20 6.9 3.8
15500 -28.2 -18.8 275 35 18 5.9 3.3 | -28.7 -19.7 275 37 19 6.8 3.7
15000 -27.4 -17.3 270 33 17 5.5 3.0 | -27.7 -17.9 275 34 18 6.5 3.5
14500 -26.6 -15.9 270 32 16 5.5 3.0 | -26.8 -16.2 280 32 17 6.5 3.6
14000 -25.7 -14.3 270 30 16 5.7 3.1 | -25.8 -14.4 280 30 16 6.5 3.6
13500 -24.9 -12.8 265 28 14 5.7 3.1 | -24.8 -12.6 280 28 15 6.6 3.6
13000 -24.0 -11.2 265 26 13 6.4 3.5 | -23.8 -10.8 280 26 14 7.8 4.3
12500 -23.0 -9.4 265 24 12 6.3 3.5 | -22.6 -8.7 275 25 13 7.7 4.2
12000 -21.9 -7.4 265 22 12 8.0 4.4 | -21.3 -6.3 275 23 12 9.0 4.9
11500 -20.8 -5.4 260 21 11 7.9 4.3 | -20.0 -4.0 275 23 12 8.9 4.9
11000 -19.6 -3.3 260 19 10 8.2 4.5 | -18.7 -1.7 275 22 11 8.9 4.9
10500 -18.3 -0.9 260 18 9 7.9 4.4 | -17.3 0.9 270 21 11 8.6 4.7
10250 -17.8 -0.0 260 18 9 6.8 3.7 | -16.7 1.9 270 21 11 7.5 4.1
10000 -17.3 0.9 255 18 9 6.8 3.8 | -16.2 2.8 270 21 11 7.8 4.3
9750 -16.7 1.9 255 18 9 10.1 5.6 | -15.5 4.1 270 21 11 10.4 5.7
9500 -15.9 3.4 255 17 9 9.9 5.4 | -14.7 5.5 270 21 11 10.0 5.5
9250 -15.3 4.5 260 16 8 7.6 4.2 | -14.1 6.6 270 21 11 8.1 4.5
9000 -14.7 5.5 260 16 8 7.6 4.2 | -13.4 7.9 270 21 11 8.5 4.6
8750 -14.1 6.6 260 15 8 9.5 5.2 | -12.8 9.0 265 21 11 9.3 5.1
8500 -13.3 8.1 260 14 7 9.8 5.4 | -11.4 11.5 265 19 10 8.6 4.7
8250 -12.6 9.3 265 14 7 8.5 4.7 | -10.8 12.6 265 18 9 8.7 4.8
8000 -12.0 10.4 265 13 7 8.5 4.6 | -10.1 13.8 265 17 9 8.8 4.8
7750 -10.5 13.1 265 12 6 10.6 5.8 | -9.4 15.1 265 17 9 9.0 5.0
7500 -9.8 14.4 265 12 6 10.3 5.6 | -8.8 16.2 265 16 8 9.5 5.2
7250 -9.0 15.8 265 11 6 8.1 4.4 | -8.1 17.4 265 15 8 8.1 4.5
7000 -8.5 16.7 270 12 6 8.0 4.4 | -7.5 18.5 265 16 8 8.4 4.6
6750 -7.7 18.1 270 11 6 11.2 6.2 | -6.8 19.8 265 16 8 10.3 5.7
6500 -6.9 19.6 270 11 5 11.4 6.3 | -6.0 21.2 265 14 7 10.1 5.5
6250 -6.1 21.0 270 10 5 10.2 5.6 | -5.2 22.6 265 13 7 11.1 6.1
6000 -5.2 22.6 275 10 5 14.4 7.9 | -4.4 24.1 265 15 8 9.2 5.1
5750 -3.8 25.2 280 10 5 25.3 13.9 | -3.9 25.0 265 13 7 7.2 4.0
5500 -2.2 28.0 280 9 5 6.5 3.6 | -2.6 27.3 265 11 5 33.9 18.6
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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