Soaring Guidance
Issued by NWS Pueblo, CO
Issued by NWS Pueblo, CO
338
UXUS97 KPUB 211205
SRGPUB
Soaring Forecast
National Weather Service Pueblo, Colorado
0605 MDT Tuesday, May 21, 2024
This forecast is for Villa Grove, CO for Tuesday, May 21, 2024:
If the trigger temperature of 46.3 F/7.9 C is reached...then
Thermal Soaring Index....................... Excellent
Maximum rate of lift........................ 1019 ft/min (5.2 m/s)
Maximum height of thermals.................. 21731 ft MSL (12717 ft AGL)
Forecast maximum temperature................... 60.0 F/16.0 C
Time of trigger temperature.................... 0745 MDT
Time of overdevelopment........................ 1100 MDT
Middle/high clouds during soaring window....... Broken/overcast thin middle
Surface winds during soaring window............ 20 mph or less
Height of the -3 thermal index................. 18622 ft MSL (9608 ft AGL)
Thermal soaring outlook for Wednesday 05/22.... Good
Wave Soaring Index............................. Not available
Remarks...
Sunrise/Sunset.................... 05:47:15 / 20:13:14 MDT
Total possible sunshine........... 14 hr 25 min 59 sec (865 min 59 sec)
Altitude of sun at 13:00:15 MDT... 72.13 degrees
Upper air data from numerical model forecast valid on 05/21/2024 at 0600 MDT
Freezing level.................. 10406 ft MSL (1392 ft AGL)
Convective condensation level... 14437 ft MSL (5423 ft AGL)
Lifted condensation level....... 16853 ft MSL (7839 ft AGL)
Lifted index.................... -5.8
K index......................... +21.0
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 -54.8 -66.6 235 49 25 3.6 2.0 M M M M M
45000 -49.4 -56.9 245 53 27 2.2 1.2 M M M M M
40000 -46.2 -51.2 245 69 35 2.2 1.2 M M M M M
38000 -46.1 -51.0 245 68 35 -1.1 -0.6 M M M M M
36000 -46.8 -52.2 245 64 33 -1.1 -0.6 M M M M M
34000 -47.3 -53.1 250 58 30 1.4 0.8 M M M M M
32000 -46.5 -51.7 260 43 22 1.2 0.7 M M M M M
30000 -44.6 -48.3 270 34 17 8.3 4.6 18.8 65.9 2.6 M M
29000 -42.0 -43.6 265 33 17 8.6 4.7 18.3 65.0 2.2 M M
28000 -39.4 -38.9 265 32 16 8.6 4.7 17.9 64.2 1.9 M M
27000 -36.9 -34.4 265 31 16 8.9 4.9 17.6 63.7 1.7 M M
26000 -34.1 -29.4 265 31 16 9.2 5.0 17.3 63.1 1.4 M M
25000 -31.4 -24.5 265 31 16 9.2 5.0 17.1 62.7 1.2 M M
24000 -28.6 -19.5 260 32 16 8.9 4.9 17.0 62.5 1.2 M M
23000 -26.2 -15.2 265 31 16 8.2 4.5 16.3 61.4 0.6 M M
22000 -23.8 -10.8 270 31 16 8.2 4.5 15.8 60.4 0.1 M M
21000 -21.4 -6.5 275 31 16 7.0 3.8 15.3 59.5 -0.3 1152 5.9
20000 -19.5 -3.1 275 35 18 6.4 3.5 14.1 57.3 -1.5 1066 5.4
19500 -18.6 -1.5 275 36 19 6.5 3.5 13.5 56.3 -2.0 1023 5.2
19000 -17.6 0.3 275 38 20 6.5 3.6 13.0 55.4 -2.5 980 5.0
18500 -16.7 1.9 275 40 21 6.8 3.8 12.5 54.5 -3.0 938 4.8
18000 -15.6 3.9 275 41 21 7.3 4.0 12.1 53.7 -3.4 891 4.5
17500 -14.0 6.8 270 42 22 7.5 4.1 11.5 52.7 -4.0 820 4.2
17000 -12.9 8.8 270 43 22 7.7 4.2 11.1 52.0 -4.4 772 3.9
16500 -11.8 10.8 270 44 23 7.7 4.2 10.8 51.4 -4.8 724 3.7
16000 -10.6 12.9 270 41 21 8.5 4.7 10.5 51.0 -5.1 673 3.4
15500 -9.3 15.3 270 36 19 8.4 4.6 10.3 50.6 -5.3 620 3.2
15000 -8.0 17.6 265 32 17 9.5 5.2 10.2 50.4 -5.5 566 2.9
14500 -6.6 20.1 270 33 17 7.8 4.3 10.2 50.4 -5.5 509 2.6
14000 -5.8 21.6 275 33 17 5.8 3.2 9.5 49.0 -6.3 472 2.4
13500 -4.9 23.2 275 35 18 6.6 3.6 9.0 48.2 -6.8 428 2.2
13000 -3.9 25.0 280 37 19 6.1 3.3 8.5 47.3 -7.4 385 2.0
12500 -3.1 26.4 285 39 20 5.8 3.2 7.9 46.2 -8.0 344 1.7
12000 -2.2 28.0 285 41 21 4.8 2.6 7.3 45.1 -8.7 304 1.5
11750 -2.0 28.4 285 40 21 3.3 1.8 6.8 44.2 -9.2 289 1.5
11500 -1.7 28.9 285 39 20 3.9 2.2 6.3 43.4 -9.7 274 1.4
11250 -1.4 29.5 285 38 20 3.3 1.8 5.9 42.6 -10.2 258 1.3
11000 -1.2 29.8 285 38 19 5.3 2.9 5.4 41.7 -10.7 243 1.2
10750 -0.7 30.7 280 35 18 7.4 4.0 5.2 41.4 -10.9 221 1.1
10500 -0.2 31.6 275 32 17 6.6 3.6 5.0 40.9 -11.2 198 1.0
10250 0.3 32.5 275 30 16 6.9 3.8 4.7 40.5 -11.4 176 0.9
10000 0.8 33.4 270 28 15 5.7 3.1 4.5 40.1 -11.7 154 0.8
9750 1.1 34.0 265 25 13 3.9 2.2 4.1 39.4 -12.1 137 0.7
9500 1.4 34.5 265 22 11 3.7 2.0 3.7 38.6 -12.6 121 0.6
9250 1.6 34.9 260 19 10 1.5 0.8 3.2 37.7 -13.2 108 0.5
9000 M M M M M M M M M M M M
8750 M M M M M M M M M M M M
8500 M M M M M M M M M M M M
8250 M M M M M M M M M M M M
8000 M M M M M M M M M M M M
* * * * * * Numerical weather prediction model forecast data valid * * * * * *
05/21/2024 at 0900 MDT | 05/21/2024 at 1200 MDT
|
CAPE... 0.0 LI... +2.1 | CAPE... +214.6 LI... -0.6
CINH... 0.0 K Index... +5.1 | CINH... 0.0 K Index... +11.5
|
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 -53.3 -63.9 235 50 26 3.2 1.8 | -52.8 -63.0 240 45 23 2.3 1.3
45000 -48.6 -55.5 245 56 29 0.4 0.2 | -49.5 -57.1 245 57 29 -0.1 -0.1
40000 -48.1 -54.6 250 64 33 0.4 0.2 | -49.8 -57.6 250 72 37 -0.2 -0.1
38000 -48.5 -55.3 250 65 34 -1.3 -0.7 | -49.7 -57.5 250 76 39 0.5 0.3
36000 -49.3 -56.7 255 66 34 -1.3 -0.7 | -49.4 -56.9 245 79 41 0.5 0.3
34000 -49.5 -57.1 255 66 34 4.8 2.6 | -48.6 -55.5 245 80 41 4.7 2.6
32000 -46.9 -52.4 255 62 32 4.4 2.4 | -45.9 -50.6 245 75 39 4.5 2.5
30000 -43.3 -45.9 255 57 29 8.0 4.4 | -42.4 -44.3 250 70 36 7.1 3.9
29000 -40.8 -41.4 255 53 27 8.1 4.4 | -40.3 -40.5 250 68 35 7.1 3.9
28000 -38.4 -37.1 250 50 26 8.1 4.4 | -38.2 -36.8 250 66 34 7.1 3.9
27000 -36.0 -32.8 245 47 24 8.0 4.4 | -36.0 -32.8 250 64 33 7.7 4.2
26000 -33.6 -28.5 240 43 22 8.0 4.4 | -33.7 -28.7 250 62 32 7.8 4.3
25000 -31.2 -24.2 235 41 21 8.0 4.4 | -31.3 -24.3 250 59 30 7.8 4.3
24000 -28.8 -19.8 225 38 20 8.2 4.5 | -29.0 -20.2 250 56 29 8.1 4.4
23000 -26.3 -15.3 230 39 20 8.5 4.7 | -26.5 -15.7 250 53 27 8.3 4.6
22000 -23.7 -10.7 230 39 20 8.5 4.7 | -24.0 -11.2 245 50 26 8.3 4.6
21000 -21.2 -6.2 230 39 20 7.8 4.3 | -21.6 -6.9 245 46 24 7.3 4.0
20000 -19.0 -2.2 240 39 20 7.6 4.2 | -19.4 -2.9 245 41 21 7.2 3.9
19500 -17.8 -0.0 245 38 20 7.6 4.2 | -18.4 -1.1 245 38 20 7.2 3.9
19000 -16.7 1.9 250 39 20 7.5 4.1 | -17.3 0.9 245 36 18 7.2 3.9
18500 -15.6 3.9 255 39 20 6.8 3.7 | -16.2 2.8 245 33 17 6.6 3.6
18000 -14.7 5.5 255 39 20 6.0 3.3 | -15.3 4.5 250 36 19 6.2 3.4
17500 -13.8 7.2 260 38 20 5.9 3.3 | -14.4 6.1 255 39 20 6.2 3.4
17000 -12.9 8.8 265 38 19 6.9 3.8 | -13.5 7.7 255 40 21 6.2 3.4
16500 -11.9 10.6 270 36 19 6.9 3.8 | -12.6 9.3 255 39 20 6.2 3.4
16000 -10.9 12.4 270 35 18 6.9 3.8 | -11.7 10.9 260 38 20 7.1 3.9
15500 -9.4 15.1 275 31 16 6.8 3.7 | -10.6 12.9 260 35 18 7.4 4.1
15000 -8.3 17.1 275 29 15 7.8 4.3 | -9.6 14.7 260 31 16 8.7 4.8
14500 -7.2 19.0 280 27 14 6.5 3.6 | -7.4 18.7 265 25 13 8.0 4.4
14000 -6.4 20.5 285 26 14 6.4 3.5 | -6.4 20.5 265 22 11 9.3 5.1
13500 -5.4 22.3 290 25 13 7.5 4.1 | -4.9 23.2 260 21 11 10.2 5.6
13000 -4.4 24.1 290 22 12 5.7 3.1 | -3.6 25.5 260 21 11 8.8 4.8
12500 -3.5 25.7 295 22 11 6.2 3.4 | -2.1 28.2 260 20 10 9.9 5.5
12000 -2.6 27.3 295 21 11 6.0 3.3 | -0.6 30.9 260 20 10 9.0 5.0
11750 -2.2 28.0 295 20 10 5.2 2.9 | 0.0 32.0 260 19 10 9.7 5.3
11500 -1.8 28.8 290 19 10 5.1 2.8 | 0.8 33.4 260 19 10 10.4 5.7
11250 -1.5 29.3 290 19 10 5.0 2.7 | 1.6 34.9 260 19 10 10.4 5.7
11000 -1.1 30.0 285 18 9 5.7 3.1 | 2.3 36.1 260 19 10 9.7 5.3
10750 -0.7 30.7 285 16 8 8.4 4.6 | 3.0 37.4 260 18 9 10.0 5.5
10500 0.0 32.0 280 15 8 9.9 5.5 | 3.8 38.8 260 18 9 11.0 6.0
10250 0.8 33.4 275 14 7 9.7 5.3 | 4.6 40.3 260 18 9 10.8 5.9
10000 1.5 34.7 275 12 6 10.2 5.6 | 5.5 41.9 260 17 9 11.1 6.1
9750 2.3 36.1 270 12 6 11.1 6.1 | 6.3 43.3 260 17 9 12.1 6.7
9500 3.1 37.6 270 11 6 10.0 5.5 | 7.2 45.0 260 16 8 10.8 5.9
9250 3.9 39.0 270 10 5 15.3 8.4 | 8.2 46.8 260 15 8 18.9 10.3
9000 6.3 43.3 270 9 5 58.0 31.8 | 11.4 52.5 260 13 7 84.7 46.5
8750 M M M M M M M | M M M M M M M
8500 M M M M M M M | M M M M M M M
8250 M M M M M M M | M M M M M M M
8000 M M M M M M M | M M M M M M M
05/21/2024 at 1500 MDT | 05/21/2024 at 1800 MDT
|
CAPE... +29.2 LI... -0.4 | CAPE... +171.3 LI... -0.8
CINH... -13.0 K Index... +22.5 | CINH... -2.0 K Index... +22.1
|
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 -52.4 -62.3 240 47 24 1.6 0.9 | -53.0 -63.4 245 45 23 0.8 0.4
45000 -50.4 -58.7 250 62 32 -1.4 -0.7 | -52.1 -61.8 255 59 30 -1.5 -0.8
40000 -52.6 -62.7 255 85 44 -1.5 -0.8 | -54.5 -66.1 255 79 41 -1.6 -0.9
38000 -51.9 -61.4 255 87 45 2.5 1.4 | -52.8 -63.0 260 84 43 5.2 2.8
36000 -50.4 -58.7 255 86 44 2.5 1.4 | -49.7 -57.5 260 88 45 5.2 2.8
34000 -48.6 -55.5 255 84 43 4.9 2.7 | -46.8 -52.2 260 90 46 4.0 2.2
32000 -45.7 -50.3 255 79 40 4.9 2.7 | -44.4 -47.9 260 88 45 3.9 2.1
30000 -42.1 -43.8 255 70 36 6.4 3.5 | -41.2 -42.2 260 85 44 6.7 3.7
29000 -40.1 -40.2 255 63 32 6.4 3.5 | -39.2 -38.6 260 83 42 6.7 3.7
28000 -38.2 -36.8 255 56 29 6.4 3.5 | -37.2 -35.0 260 80 41 6.7 3.7
27000 -36.2 -33.2 255 49 25 8.1 4.4 | -35.2 -31.4 260 78 40 7.1 3.9
26000 -33.7 -28.7 250 42 22 8.3 4.6 | -33.1 -27.6 255 73 38 7.1 3.9
25000 -31.2 -24.2 250 36 18 8.4 4.6 | -30.9 -23.6 255 69 35 7.1 3.9
24000 -28.8 -19.8 240 29 15 8.4 4.6 | -28.8 -19.8 255 64 33 7.8 4.3
23000 -26.3 -15.3 245 30 15 8.5 4.7 | -26.4 -15.5 255 55 28 8.2 4.5
22000 -23.7 -10.7 245 31 16 8.5 4.7 | -24.0 -11.2 250 46 24 8.3 4.5
21000 -21.3 -6.3 245 32 16 7.5 4.1 | -21.6 -6.9 245 39 20 7.7 4.2
20000 -19.1 -2.4 250 32 17 7.4 4.1 | -19.3 -2.7 245 40 21 7.7 4.2
19500 -18.0 -0.4 250 33 17 7.4 4.1 | -18.2 -0.8 245 41 21 7.7 4.2
19000 -16.9 1.6 250 33 17 7.4 4.1 | -17.0 1.4 245 42 21 7.7 4.2
18500 -15.8 3.6 250 34 17 7.4 4.0 | -15.9 3.4 245 42 22 7.5 4.1
18000 -14.8 5.4 250 33 17 7.3 4.0 | -14.8 5.4 245 40 21 7.4 4.0
17500 -13.7 7.3 250 33 17 7.3 4.0 | -13.8 7.2 245 39 20 7.3 4.0
17000 -12.6 9.3 250 33 17 7.4 4.1 | -12.8 9.0 245 38 20 6.5 3.6
16500 -11.5 11.3 250 32 17 7.4 4.1 | -11.8 10.8 250 38 20 6.6 3.6
16000 -10.4 13.3 250 31 16 7.4 4.1 | -10.8 12.6 250 37 19 6.9 3.8
15500 -9.4 15.1 250 30 16 7.4 4.1 | -9.8 14.4 250 36 19 6.9 3.8
15000 -7.7 18.1 250 29 15 7.7 4.2 | -8.8 16.2 255 35 18 7.2 3.9
14500 -6.6 20.1 250 28 14 6.4 3.5 | -7.7 18.1 255 34 18 7.8 4.3
14000 -5.9 21.4 250 25 13 5.8 3.2 | -6.4 20.5 260 33 17 7.5 4.1
13500 -5.0 23.0 250 21 11 6.2 3.4 | -5.3 22.5 265 31 16 7.7 4.2
13000 -4.1 24.6 255 19 10 5.0 2.8 | -4.1 24.6 265 28 15 8.5 4.7
12500 -3.4 25.9 265 19 10 4.9 2.7 | -2.8 27.0 265 27 14 8.9 4.9
12000 -2.7 27.1 270 21 11 4.4 2.4 | -1.6 29.1 270 25 13 8.2 4.5
11750 -2.4 27.7 275 22 11 4.2 2.3 | -1.0 30.2 270 25 13 9.6 5.3
11500 -2.1 28.2 280 22 11 4.4 2.4 | -0.2 31.6 270 24 12 10.1 5.5
11250 -1.8 28.8 280 23 12 4.4 2.4 | 0.5 32.9 270 23 12 9.9 5.5
11000 -1.5 29.3 285 24 12 4.5 2.5 | 1.3 34.3 270 23 12 9.8 5.4
10750 -1.1 30.0 285 24 12 6.2 3.4 | 2.0 35.6 270 22 11 9.9 5.4
10500 -0.6 30.9 285 23 12 7.8 4.3 | 2.7 36.9 270 22 11 10.1 5.6
10250 -0.1 31.8 290 21 11 7.8 4.3 | 3.5 38.3 270 21 11 10.1 5.6
10000 0.5 32.9 290 19 10 7.3 4.0 | 4.2 39.6 270 20 10 10.3 5.6
9750 1.0 33.8 290 17 9 7.4 4.0 | 5.0 41.0 265 19 10 10.4 5.7
9500 1.6 34.9 290 15 8 8.0 4.4 | 5.8 42.4 265 18 9 9.7 5.3
9250 2.3 36.1 290 13 6 12.2 6.7 | 6.5 43.7 265 16 8 11.1 6.1
9000 3.8 38.8 285 9 5 34.1 18.7 | 7.7 45.9 265 12 6 28.1 15.4
8750 M M M M M M M | M M M M M M M
8500 M M M M M M M | M M M M M M M
8250 M M M M M M M | M M M M M M M
8000 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). 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 Villa Grove, Colorado at:
North Latitude: 38 deg 16 min 03 sec
West Longitude: 105 deg 53 min 37 sec
Elevation: 7986 feet (2434 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.
CIN (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