Soaring Guidance
Issued by NWS Grand Junction, CO
Issued by NWS Grand Junction, CO
520
UXUS97 KGJT 061306
SRGGJT
Soaring Forecast
National Weather Service Grand Junction, Colorado
606 AM MST Wednesday, November 6, 2024
This forecast is for Wednesday, November 6, 2024:
If the trigger temperature of 37.7 F/3.2 C is reached...then
Thermal Soaring Index....................... Poor
Maximum rate of lift........................ 74 ft/min (0.4 m/s)
Maximum height of thermals.................. 11025 ft MSL (6186 ft AGL)
Forecast maximum temperature................... 41.0 F/5.5 C
Time of trigger temperature.................... 1200 MST
Time of overdevelopment........................ None
Middle/high clouds during soaring window....... Broken/overcast opaque middle
Surface winds during soaring window............ 20 mph or less
Height of the -3 thermal index................. 7736 ft MSL (2897 ft AGL)
Thermal soaring outlook for Thursday 11/07..... Poor
Wave Soaring Index............................. Not available
Remarks...
Sunrise/Sunset.................... 06:48:10 / 17:07:20 MST
Total possible sunshine........... 10 hr 19 min 11 sec (619 min 11 sec)
Altitude of sun at 11:57:45 MST... 34.59 degrees
Upper air data from rawinsonde observation taken on 11/06/2024 at 0500 MST
Freezing level.................. 4910 ft MSL (71 ft AGL)
Convective condensation level... 9569 ft MSL (4730 ft AGL)
Lifted condensation level....... 10089 ft MSL (5250 ft AGL)
Lifted index.................... +4.2
K index......................... +12.6
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 -51.6 -60.9 320 16 8 -0.3 -0.2 117.6 243.7 63.9 M M
45000 -50.2 -58.4 260 12 6 2.8 1.6 94.8 202.7 54.4 M M
40000 -46.1 -51.0 280 22 11 -1.4 -0.8 77.1 170.8 46.8 M M
38000 -45.9 -50.6 265 20 10 1.9 1.0 68.5 155.4 42.3 M M
36000 -44.7 -48.5 295 15 8 4.0 2.2 61.7 143.1 38.7 M M
34000 -43.5 -46.3 255 19 10 2.5 1.4 54.9 130.9 34.9 M M
32000 -43.9 -47.0 245 16 8 7.2 3.9 46.2 115.1 29.6 M M
30000 -45.9 -50.6 240 14 7 0.1 0.1 34.4 93.9 21.7 M M
29000 -44.3 -47.7 225 20 10 4.7 2.6 32.6 90.6 20.6 M M
28000 -43.6 -46.5 245 15 8 -4.7 -2.6 29.7 85.4 18.7 M M
27000 -43.8 -46.8 200 17 9 6.2 3.4 25.6 78.1 15.8 M M
26000 -43.2 -45.8 175 15 8 3.3 1.8 22.6 72.6 13.6 M M
25000 -42.9 -45.2 170 17 9 2.2 1.2 19.2 66.6 11.2 M M
24000 -41.4 -42.5 155 16 8 8.2 4.5 17.5 63.5 10.0 M M
23000 -39.1 -38.4 150 15 8 6.7 3.7 16.6 61.9 9.4 M M
22000 -38.0 -36.4 125 25 13 1.5 0.8 14.5 58.0 7.7 M M
21000 -36.7 -34.1 130 26 14 6.5 3.6 12.5 54.5 6.2 M M
20000 -34.2 -29.6 145 21 11 9.0 4.9 11.9 53.5 5.8 M M
19500 -32.9 -27.2 130 14 7 9.0 5.0 11.8 53.2 5.7 M M
19000 -31.6 -24.9 125 13 7 9.0 5.0 11.6 53.0 5.6 M M
18500 -30.2 -22.4 115 14 7 8.8 4.8 11.5 52.7 5.5 M M
18000 -28.9 -20.0 095 15 8 8.2 4.5 11.3 52.3 5.3 M M
17500 -27.8 -18.0 070 14 7 7.1 3.9 10.9 51.6 5.0 M M
17000 -26.7 -16.1 070 15 8 7.7 4.2 10.5 50.9 4.7 M M
16500 -25.0 -13.0 055 13 7 7.2 4.0 9.9 49.9 4.2 M M
16000 -24.0 -11.2 040 14 7 7.1 3.9 9.5 49.1 3.9 M M
15500 -22.9 -9.2 055 16 8 7.1 3.9 9.0 48.3 3.5 M M
15000 -21.9 -7.4 060 17 9 7.1 3.9 8.6 47.5 3.1 M M
14500 -20.8 -5.4 060 21 11 7.1 3.9 8.2 46.7 2.7 M M
14000 -19.8 -3.6 050 19 10 7.2 3.9 7.7 45.9 2.3 M M
13500 -18.7 -1.7 045 21 11 7.2 3.9 7.3 45.2 1.9 M M
13000 -17.6 0.3 040 23 12 7.2 3.9 6.9 44.4 1.6 M M
12500 -16.6 2.1 040 20 10 7.2 3.9 6.5 43.7 1.2 M M
12000 -15.5 4.1 045 21 11 7.2 3.9 6.1 42.9 0.8 M M
11500 -14.5 5.9 050 20 10 7.2 3.9 5.6 42.1 0.4 M M
11000 -13.4 7.9 050 20 10 7.2 3.9 5.2 41.4 -0.0 469 2.4
10500 -12.4 9.7 045 23 12 7.2 3.9 4.8 40.7 -0.4 423 2.1
10250 -11.8 10.8 040 22 11 7.2 3.9 4.6 40.3 -0.6 399 2.0
10000 -11.3 11.7 035 22 11 7.2 4.0 4.4 39.9 -0.8 376 1.9
9750 -10.8 12.6 040 25 13 7.4 4.1 4.2 39.6 -1.0 353 1.8
9500 -10.2 13.6 040 27 14 7.5 4.1 4.0 39.3 -1.2 329 1.7
9250 -9.7 14.5 040 29 15 7.6 4.1 3.9 39.7 -1.4 305 1.5
9000 -9.1 15.6 035 32 16 7.2 3.9 3.7 38.6 -1.6 281 1.4
8750 -8.6 16.5 035 32 16 6.4 3.5 3.5 38.2 -1.8 259 1.3
8500 -8.2 17.2 035 29 15 6.3 3.5 3.2 37.7 -2.1 238 1.2
8250 -7.7 18.1 030 27 14 6.2 3.4 2.9 37.3 -2.4 216 1.1
8000 -7.2 19.0 030 23 12 6.8 3.7 2.7 36.8 -2.6 195 1.0
7750 -6.8 19.8 030 21 11 4.6 2.5 2.4 36.3 -2.9 174 0.9
7500 -6.5 20.3 025 19 10 5.7 3.1 1.9 35.5 -3.4 158 0.8
7250 -5.9 21.4 015 17 9 8.7 4.8 1.8 35.3 -3.5 133 0.7
7000 -5.3 22.5 005 15 8 7.8 4.3 1.7 35.0 -3.7 108 0.5
6750 -4.8 23.4 010 12 6 5.8 3.2 1.5 34.7 -3.9 85 0.4
6500 -4.4 24.1 355 8 4 5.8 3.2 1.1 34.1 -4.2 66 0.3
6250 -3.9 25.0 335 8 4 7.8 4.3 0.9 33.7 -4.4 43 0.2
6000 -3.3 26.1 320 9 5 7.9 4.3 0.8 33.5 -4.6 18 0.1
5750 -2.7 27.1 320 8 4 7.8 4.3 0.7 33.2 -4.8 M M
5500 -2.1 28.2 310 7 3 8.0 4.4 0.5 32.9 -4.9 M M
5250 -1.6 29.1 295 6 3 7.3 4.0 0.4 32.7 -5.1 M M
5000 -1.0 30.2 275 6 3 10.1 5.5 0.2 32.4 -5.2 M M
* * * * * * Numerical weather prediction model forecast data valid * * * * * *
11/06/2024 at 0800 MST | 11/06/2024 at 1100 MST
|
CAPE... 0.0 LI... +2.6 | CAPE... 0.0 LI... +2.3
CINH... -0.3 K Index... +15.1 | CINH... 0.0 K Index... +14.9
|
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 -53.4 -64.1 345 6 3 2.1 1.1 | -53.3 -63.9 350 8 4 2.4 1.3
45000 -50.2 -58.4 310 10 5 2.1 1.1 | -49.7 -57.5 340 9 5 2.4 1.3
40000 -46.4 -51.5 325 11 6 2.5 1.4 | -46.9 -52.4 015 11 6 1.9 1.0
38000 -45.1 -49.2 325 11 6 1.1 0.6 | -45.7 -50.3 020 12 6 1.6 0.9
36000 -44.5 -48.1 310 7 4 1.1 0.6 | -44.8 -48.6 015 11 6 1.5 0.9
34000 -43.8 -46.8 275 5 3 1.1 0.6 | -43.8 -46.8 010 11 5 1.7 0.9
32000 -43.8 -46.8 275 3 1 -0.3 -0.2 | -43.5 -46.3 025 9 4 0.3 0.2
30000 -43.9 -47.0 355 1 1 -0.3 -0.2 | -43.3 -45.9 055 8 4 0.3 0.2
29000 -44.0 -47.2 065 2 1 -0.5 -0.3 | -43.2 -45.8 070 8 4 0.6 0.3
28000 -44.2 -47.6 115 4 2 -0.5 -0.3 | -43.0 -45.4 080 9 4 0.6 0.3
27000 -44.4 -47.9 125 8 4 -0.6 -0.3 | -42.8 -45.0 085 9 5 0.6 0.3
26000 -44.2 -47.6 125 11 6 4.6 2.5 | -42.6 -44.7 095 10 5 2.6 1.4
25000 -43.0 -45.4 115 14 7 4.2 2.3 | -41.7 -43.1 095 13 7 3.0 1.6
24000 -41.7 -43.1 105 18 9 4.1 2.3 | -40.8 -41.4 095 15 8 2.9 1.6
23000 -40.2 -40.4 100 20 11 8.5 4.7 | -39.2 -38.6 095 18 9 7.6 4.2
22000 -37.8 -36.0 100 18 10 8.0 4.4 | -37.0 -34.6 095 17 9 7.4 4.1
21000 -35.4 -31.7 095 17 9 8.0 4.4 | -34.8 -30.6 090 17 9 7.3 4.0
20000 -33.0 -27.4 085 16 8 8.2 4.5 | -32.4 -26.3 085 17 9 8.4 4.6
19500 -31.7 -25.1 080 16 8 8.2 4.5 | -31.1 -24.0 085 17 9 8.4 4.6
19000 -30.5 -22.9 080 16 8 8.2 4.5 | -29.9 -21.8 085 17 9 8.4 4.6
18500 -29.3 -20.7 075 16 8 8.2 4.5 | -28.7 -19.7 085 16 8 8.4 4.6
18000 -28.1 -18.6 070 16 8 8.1 4.4 | -27.4 -17.3 085 16 8 8.1 4.4
17500 -26.9 -16.4 070 17 9 8.0 4.4 | -26.2 -15.2 085 16 8 8.1 4.4
17000 -25.7 -14.3 065 19 10 7.9 4.3 | -25.0 -13.0 085 16 8 7.9 4.3
16500 -24.6 -12.3 065 20 10 7.3 4.0 | -23.9 -11.0 090 16 8 7.7 4.2
16000 -23.5 -10.3 065 21 11 7.3 4.0 | -22.8 -9.0 090 17 9 7.6 4.2
15500 -22.4 -8.3 065 22 11 7.4 4.0 | -21.7 -7.1 095 17 9 7.3 4.0
15000 -21.3 -6.3 065 23 12 7.4 4.1 | -20.6 -5.1 095 18 9 7.4 4.0
14500 -20.2 -4.4 065 25 13 7.0 3.9 | -19.5 -3.1 095 19 10 7.1 3.9
14000 -19.2 -2.6 065 25 13 7.0 3.9 | -18.4 -1.1 095 19 10 7.2 3.9
13500 -18.2 -0.8 065 26 14 6.8 3.8 | -17.4 0.7 090 20 10 7.1 3.9
13000 -17.1 1.2 065 27 14 6.8 3.7 | -16.3 2.7 090 20 10 7.1 3.9
12500 -16.1 3.0 065 28 15 6.7 3.7 | -15.3 4.5 085 21 11 7.0 3.8
12000 -15.1 4.8 060 29 15 6.7 3.7 | -14.3 6.3 080 22 11 7.0 3.8
11500 -14.1 6.6 060 30 16 7.0 3.8 | -13.2 8.2 080 22 11 6.8 3.7
11000 -13.1 8.4 060 31 16 7.1 3.9 | -12.2 10.0 075 23 12 6.8 3.7
10500 -12.0 10.4 060 32 16 7.3 4.0 | -11.2 11.8 070 23 12 6.8 3.7
10250 -11.5 11.3 055 32 17 7.3 4.0 | -10.7 12.7 070 23 12 7.2 4.0
10000 -10.9 12.4 055 32 17 7.2 3.9 | -10.2 13.6 070 23 12 5.7 3.1
9750 -9.9 14.2 055 31 16 6.8 3.7 | -9.8 14.4 065 22 11 5.6 3.1
9500 -9.4 15.1 050 30 15 6.5 3.6 | -9.3 15.3 060 22 12 7.2 3.9
9250 -8.9 16.0 050 29 15 7.8 4.3 | -8.8 16.2 060 23 12 6.2 3.4
9000 -8.3 17.1 050 30 15 7.5 4.1 | -8.3 17.1 060 23 12 8.3 4.6
8750 -7.8 18.0 050 29 15 6.1 3.3 | -7.2 19.0 055 23 12 5.3 2.9
8500 -7.4 18.7 050 29 15 6.3 3.5 | -6.8 19.8 050 22 11 5.8 3.2
8250 -6.9 19.6 045 28 15 6.8 3.7 | -6.4 20.5 045 21 11 6.7 3.7
8000 -6.4 20.5 045 30 15 6.7 3.7 | -5.8 21.6 045 22 11 8.3 4.6
7750 -5.9 21.4 045 29 15 6.0 3.3 | -5.2 22.6 040 21 11 8.5 4.7
7500 -5.5 22.1 040 27 14 6.1 3.3 | -4.5 23.9 035 20 10 8.3 4.6
7250 -5.0 23.0 035 27 14 5.3 2.9 | -3.9 25.0 035 20 10 7.4 4.1
7000 -4.6 23.7 035 27 14 6.2 3.4 | -3.4 25.9 035 21 11 9.0 4.9
6750 -4.1 24.6 035 24 12 7.4 4.1 | -2.6 27.3 035 19 10 10.8 5.9
6500 -3.5 25.7 030 21 11 8.0 4.4 | -1.8 28.8 030 18 9 10.0 5.5
6250 -2.9 26.8 030 19 10 8.9 4.9 | -1.1 30.0 030 18 9 10.4 5.7
6000 -2.3 27.9 025 17 9 7.9 4.3 | -0.3 31.5 030 18 9 8.3 4.6
5750 -1.8 28.8 025 15 7 6.4 3.5 | 0.2 32.4 030 14 7 9.3 5.1
5500 -1.2 29.8 020 8 4 11.2 6.2 | 2.0 35.6 025 13 7 50.9 27.9
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
11/06/2024 at 1400 MST | 11/06/2024 at 1700 MST
|
CAPE... +0.4 LI... +2.2 | CAPE... 0.0 LI... +2.0
CINH... -1.5 K Index... +13.7 | CINH... -0.2 K Index... +13.4
|
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 -53.9 -65.0 005 12 6 2.4 1.3 | -54.4 -65.9 015 14 7 2.2 1.2
45000 -50.4 -58.7 015 17 9 2.4 1.3 | -51.1 -60.0 035 19 10 2.2 1.2
40000 -46.9 -52.4 025 12 6 2.3 1.3 | -47.4 -53.3 035 23 12 2.3 1.3
38000 -45.6 -50.1 035 12 6 1.4 0.8 | -46.2 -51.2 040 24 13 1.7 1.0
36000 -44.8 -48.6 040 14 7 1.4 0.8 | -45.1 -49.2 045 26 13 1.7 1.0
34000 -43.9 -47.0 045 17 9 1.4 0.8 | -44.1 -47.4 045 27 14 1.8 1.0
32000 -43.2 -45.8 045 16 8 1.1 0.6 | -43.0 -45.4 045 30 15 1.9 1.1
30000 -42.5 -44.5 050 15 8 1.2 0.7 | -41.8 -43.2 045 33 17 2.2 1.2
29000 -42.4 -44.3 055 14 7 0.0 0.0 | -41.7 -43.1 050 30 15 -0.0 -0.0
28000 -42.4 -44.3 065 12 6 0.0 0.0 | -41.7 -43.1 050 25 13 -0.0 -0.0
27000 -42.4 -44.3 075 11 6 0.0 0.0 | -41.7 -43.1 055 21 11 -0.0 -0.0
26000 -42.2 -44.0 095 11 6 3.6 2.0 | -41.2 -42.2 070 15 8 2.9 1.6
25000 -41.1 -42.0 135 13 7 3.6 2.0 | -40.3 -40.5 100 13 7 3.0 1.7
24000 -39.8 -39.6 160 22 11 3.7 2.0 | -39.4 -38.9 130 16 8 3.2 1.8
23000 -38.2 -36.8 165 26 13 8.0 4.4 | -37.7 -35.9 135 17 9 8.2 4.5
22000 -35.8 -32.4 165 25 13 7.9 4.4 | -35.2 -31.4 125 15 8 8.4 4.6
21000 -33.4 -28.1 165 24 13 8.0 4.4 | -32.7 -26.9 115 13 7 8.4 4.6
20000 -31.0 -23.8 160 21 11 7.9 4.3 | -30.3 -22.5 100 12 6 8.1 4.4
19500 -29.9 -21.8 155 19 10 7.9 4.3 | -29.0 -20.2 090 12 6 8.1 4.4
19000 -28.7 -19.7 150 17 9 7.9 4.3 | -27.8 -18.0 085 12 6 8.1 4.4
18500 -27.5 -17.5 145 15 8 8.0 4.4 | -26.6 -15.9 075 12 6 8.1 4.4
18000 -26.4 -15.5 135 14 7 7.6 4.2 | -25.4 -13.7 070 13 7 8.4 4.6
17500 -25.2 -13.4 125 13 7 7.6 4.2 | -24.2 -11.6 070 13 7 8.4 4.6
17000 -24.1 -11.4 115 12 6 7.6 4.2 | -22.9 -9.2 070 14 7 8.1 4.4
16500 -23.0 -9.4 105 13 6 7.6 4.2 | -21.7 -7.1 070 15 8 8.0 4.4
16000 -21.8 -7.2 100 13 7 7.7 4.2 | -20.5 -4.9 075 15 8 7.9 4.3
15500 -20.7 -5.3 095 13 7 7.8 4.3 | -19.4 -2.9 075 16 8 7.6 4.2
15000 -19.5 -3.1 095 14 7 7.8 4.3 | -18.3 -0.9 075 16 8 7.6 4.2
14500 -18.4 -1.1 095 14 7 7.8 4.3 | -17.2 1.0 080 16 8 7.4 4.0
14000 -17.2 1.0 090 14 7 7.9 4.3 | -16.1 3.0 080 16 8 7.4 4.1
13500 -16.1 3.0 090 14 7 6.8 3.7 | -15.0 5.0 080 15 8 7.0 3.8
13000 -15.1 4.8 085 13 7 6.9 3.8 | -14.0 6.8 080 15 8 7.0 3.9
12500 -14.1 6.6 080 13 7 7.0 3.8 | -12.9 8.8 080 15 8 7.1 3.9
12000 -13.1 8.4 075 14 7 7.0 3.9 | -11.9 10.6 080 16 8 7.2 3.9
11500 -12.1 10.2 065 15 8 6.3 3.4 | -10.8 12.6 080 17 9 6.5 3.6
11000 -11.1 12.0 060 17 9 6.3 3.4 | -9.9 14.2 075 18 9 6.6 3.6
10500 -10.2 13.6 055 18 9 6.8 3.7 | -8.8 16.2 075 19 10 7.3 4.0
10250 -9.7 14.5 055 18 9 6.6 3.6 | -8.3 17.1 070 19 10 7.2 3.9
10000 -9.2 15.4 055 18 9 7.1 3.9 | -7.8 18.0 070 19 10 7.2 3.9
9750 -8.6 16.5 045 19 10 8.1 4.4 | -7.2 19.0 065 19 10 7.5 4.1
9500 -8.0 17.6 040 19 10 8.4 4.6 | -6.7 19.9 060 19 10 7.9 4.3
9250 -7.4 18.7 040 19 10 8.2 4.5 | -6.1 21.0 060 18 9 7.3 4.0
9000 -6.8 19.8 035 19 10 8.4 4.6 | -5.5 22.1 055 18 9 9.2 5.1
8750 -6.1 21.0 040 19 10 8.9 4.9 | -4.2 24.4 055 18 9 6.8 3.7
8500 -4.8 23.4 035 20 10 9.0 5.0 | -3.7 25.3 050 17 9 7.3 4.0
8250 -4.1 24.6 030 20 10 8.8 4.8 | -3.1 26.4 045 17 9 8.7 4.8
8000 -3.5 25.7 035 20 10 9.2 5.1 | -2.4 27.7 050 18 9 8.8 4.8
7750 -2.7 27.1 030 20 10 9.9 5.4 | -1.8 28.8 045 17 9 7.6 4.2
7500 -2.0 28.4 030 19 10 9.4 5.1 | -1.2 29.8 040 16 8 8.1 4.5
7250 -1.4 29.5 025 20 10 8.1 4.5 | -0.6 30.9 040 17 9 8.4 4.6
7000 -0.8 30.6 030 21 11 9.3 5.1 | -0.0 32.0 040 17 9 8.3 4.6
6750 0.0 32.0 025 19 10 10.9 6.0 | 0.6 33.1 035 15 8 8.4 4.6
6500 0.8 33.4 025 18 9 10.3 5.7 | 1.3 34.3 030 14 7 8.8 4.8
6250 1.6 34.9 025 18 9 11.1 6.1 | 1.9 35.4 030 14 7 9.7 5.3
6000 2.4 36.3 025 19 10 8.5 4.7 | 2.6 36.7 030 13 7 7.0 3.8
5750 3.0 37.4 025 16 8 9.5 5.2 | 2.8 37.0 025 9 5 -1.6 -0.9
5500 4.9 40.8 025 14 7 56.9 31.2 | 2.6 36.7 020 5 3 -0.7 -0.4
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
________________________________________________________________________________
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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