Soaring Guidance
Issued by NWS Pueblo, CO
Issued by NWS Pueblo, CO
318
UXUS97 KPUB 101239
SRGPUB
Soaring Forecast
National Weather Service Pueblo, Colorado
0638 MDT Friday, October 10, 2025
This forecast is for Villa Grove, CO for Friday, October 10, 2025:
If the trigger temperature of 61.5 F/16.4 C is reached...then
Thermal Soaring Index....................... Poor
Maximum rate of lift........................ 124 ft/min (0.6 m/s)
Maximum height of thermals.................. 12223 ft MSL (3251 ft AGL)
Forecast maximum temperature................... 60.0 F/16.0 C
Time of trigger temperature.................... 1415 MDT
Time of overdevelopment........................ None
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................. 10237 ft MSL (1266 ft AGL)
Thermal soaring outlook for Saturday 10/11..... Poor
Wave Soaring Index............................. Not available
Remarks...
Sunrise/Sunset.................... 07:08:13 / 18:32:37 MDT
Total possible sunshine........... 11 hr 24 min 24 sec (684 min 24 sec)
Altitude of sun at 12:50:25 MDT... 44.72 degrees
Upper air data from numerical model forecast valid on 10/10/2025 at 0600 MDT
Freezing level.................. 14965 ft MSL (5993 ft AGL)
Convective condensation level... 14677 ft MSL (5705 ft AGL)
Lifted condensation level....... 13864 ft MSL (4893 ft AGL)
Lifted index.................... +1.2
K index......................... +22.7
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 -66.9 -88.4 260 47 24 5.4 3.0 M M M M M
45000 -58.4 -73.1 265 65 34 6.0 3.3 M M M M M
40000 -49.7 -57.5 265 78 40 4.6 2.5 M M M M M
38000 -46.9 -52.4 265 69 35 4.6 2.5 M M M M M
36000 -44.2 -47.6 265 59 31 4.4 2.4 M M M M M
34000 -40.3 -40.5 265 53 27 6.8 3.7 M M M M M
32000 -35.7 -32.3 260 47 24 7.5 4.1 M M M M M
30000 -30.4 -22.7 250 42 22 9.1 5.0 34.0 93.2 14.5 M M
29000 -27.7 -17.9 245 40 21 9.1 5.0 33.8 92.9 14.5 M M
28000 -25.2 -13.4 235 38 19 6.0 3.3 33.5 92.2 14.4 M M
27000 -23.4 -10.1 230 29 15 5.8 3.2 31.9 89.4 13.2 M M
26000 -21.7 -7.1 220 22 11 5.9 3.2 30.5 86.9 12.2 M M
25000 -20.0 -4.0 200 16 8 6.1 3.4 29.2 84.6 11.2 M M
24000 -18.0 -0.4 200 17 9 6.9 3.8 28.0 82.5 10.3 M M
23000 -15.9 3.4 200 18 9 6.9 3.8 27.0 80.7 9.5 M M
22000 -13.9 7.0 200 19 10 7.1 3.9 26.1 79.1 8.8 M M
21000 -11.8 10.8 200 18 9 7.4 4.1 25.3 77.5 8.1 M M
20000 -9.6 14.7 200 18 9 7.5 4.1 24.5 76.1 7.4 M M
19500 -8.5 16.7 200 17 9 7.6 4.2 24.1 75.4 7.1 M M
19000 -7.6 18.3 195 17 8 5.1 2.8 23.6 74.4 6.6 M M
18500 -6.8 19.8 190 16 8 5.4 3.0 22.8 73.1 6.0 M M
18000 -6.0 21.2 185 15 8 5.9 3.2 22.1 71.9 5.3 M M
17500 -5.1 22.8 180 16 8 6.4 3.5 21.6 70.8 4.8 M M
17000 -4.2 24.4 175 16 8 6.4 3.5 21.0 69.8 4.3 M M
16500 -3.3 26.1 175 17 9 6.5 3.6 20.5 68.9 3.8 M M
16000 -2.3 27.9 175 17 9 6.5 3.6 20.0 67.9 3.3 M M
15500 -0.9 30.4 170 18 9 6.8 3.7 19.2 66.6 2.6 M M
15000 0.2 32.4 170 19 10 6.7 3.7 18.7 65.7 2.2 M M
14500 1.2 34.2 170 19 10 7.4 4.1 18.3 64.9 1.8 M M
14000 2.3 36.1 170 19 10 7.6 4.2 17.9 64.3 1.4 M M
13500 3.5 38.3 170 19 10 8.5 4.7 17.7 63.8 1.1 M M
13000 4.5 40.1 170 18 9 6.6 3.6 17.3 63.2 0.7 M M
12500 5.5 41.9 175 18 9 6.9 3.8 16.9 62.3 0.2 M M
12000 6.4 43.5 180 17 9 6.9 3.8 16.5 61.6 -0.3 298 1.5
11750 6.9 44.4 180 17 9 6.6 3.6 16.2 61.2 -0.6 277 1.4
11500 7.3 45.1 185 17 9 5.7 3.1 16.0 60.7 -0.9 257 1.3
11250 7.7 45.9 185 17 9 5.1 2.8 15.6 60.1 -1.3 239 1.2
11000 8.0 46.4 185 16 8 5.2 2.8 15.2 59.4 -1.6 220 1.1
10750 8.4 47.1 190 16 8 5.5 3.0 14.9 58.8 -2.0 202 1.0
10500 8.7 47.7 190 15 8 2.5 1.4 14.5 58.1 -2.4 184 0.9
10250 8.8 47.8 190 14 7 -0.2 -0.1 13.8 56.8 -3.1 176 0.9
10000 8.8 47.8 195 13 7 0.9 0.5 13.1 55.6 -3.8 167 0.8
9750 8.9 48.0 195 12 6 -0.9 -0.5 12.4 54.3 -4.5 159 0.8
9500 8.6 47.5 200 11 6 -5.8 -3.2 11.4 52.5 -5.4 158 0.8
9250 8.1 46.6 205 7 4 -8.9 -4.9 10.1 50.2 -6.7 165 0.8
9000 7.6 45.7 225 4 2 -4.6 -2.5 8.8 47.8 -7.9 173 0.9
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 * * * * * *
10/10/2025 at 0900 MDT | 10/10/2025 at 1200 MDT
|
CAPE... 0.0 LI... -1.1 | CAPE... +7.6 LI... -0.2
CINH... -9.0 K Index... +24.5 | CINH... -6.6 K Index... +25.6
|
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 -67.6 -89.7 265 49 25 4.1 2.3 | -68.5 -91.3 260 43 22 4.1 2.2
45000 -60.2 -76.4 265 70 36 6.6 3.6 | -60.7 -77.3 260 60 31 7.3 4.0
40000 -50.4 -58.7 265 72 37 5.9 3.2 | -49.9 -57.8 260 64 33 6.9 3.8
38000 -46.8 -52.2 265 64 33 5.9 3.2 | -45.7 -50.3 260 60 31 6.9 3.8
36000 -43.3 -45.9 270 57 29 5.8 3.2 | -41.6 -42.9 260 57 29 7.2 3.9
34000 -39.7 -39.5 270 45 23 6.1 3.3 | -38.5 -37.3 255 47 24 4.8 2.6
32000 -35.6 -32.1 275 31 16 6.8 3.7 | -35.3 -31.5 245 36 18 5.7 3.1
30000 -30.3 -22.5 270 32 16 9.1 5.0 | -30.0 -22.0 245 30 16 9.1 5.0
29000 -27.6 -17.7 265 33 17 9.1 5.0 | -27.3 -17.1 245 28 14 9.1 5.0
28000 -25.0 -13.0 265 34 17 7.8 4.3 | -24.6 -12.3 250 26 13 7.6 4.1
27000 -22.7 -8.9 260 32 17 7.8 4.3 | -22.4 -8.3 250 24 12 7.6 4.2
26000 -20.4 -4.7 255 31 16 7.8 4.3 | -20.2 -4.4 255 23 12 7.6 4.2
25000 -18.1 -0.6 250 30 15 7.3 4.0 | -17.9 -0.2 255 21 11 7.3 4.0
24000 -16.3 2.7 245 28 14 6.0 3.3 | -16.0 3.2 255 21 11 6.4 3.5
23000 -14.5 5.9 235 27 14 6.0 3.3 | -14.2 6.4 250 20 11 6.5 3.6
22000 -12.8 9.0 225 27 14 6.0 3.3 | -12.3 9.9 245 20 10 6.6 3.6
21000 -11.1 12.0 220 27 14 5.9 3.2 | -10.4 13.3 245 20 10 6.6 3.6
20000 -9.4 15.1 215 28 14 5.9 3.2 | -8.5 16.7 245 19 10 6.6 3.6
19500 -8.5 16.7 215 28 14 5.9 3.3 | -7.5 18.5 245 18 9 6.8 3.7
19000 -7.7 18.1 210 28 14 5.8 3.2 | -6.6 20.1 245 18 9 5.7 3.1
18500 -6.9 19.6 210 28 14 5.8 3.2 | -5.8 21.6 245 18 9 5.8 3.2
18000 -6.0 21.2 205 28 14 5.8 3.2 | -5.0 23.0 245 18 9 5.8 3.2
17500 -5.2 22.6 200 28 14 5.8 3.2 | -4.1 24.6 240 19 10 5.7 3.1
17000 -4.3 24.3 195 27 14 5.8 3.2 | -3.3 26.1 240 19 10 5.7 3.1
16500 -3.5 25.7 190 27 14 5.9 3.2 | -2.5 27.5 235 20 10 5.7 3.1
16000 -2.6 27.3 185 27 14 5.9 3.2 | -1.7 28.9 235 20 10 5.8 3.2
15500 -1.8 28.8 185 27 14 6.2 3.4 | -0.5 31.1 235 21 11 4.5 2.5
15000 -0.4 31.3 180 26 14 6.4 3.5 | 0.1 32.2 235 21 11 4.6 2.5
14500 0.4 32.7 180 26 13 6.1 3.4 | 0.8 33.4 230 22 11 5.4 2.9
14000 1.4 34.5 180 25 13 6.8 3.8 | 1.7 35.1 230 22 11 6.0 3.3
13500 2.4 36.3 180 25 13 7.5 4.1 | 2.5 36.5 230 22 11 6.2 3.4
13000 3.5 38.3 185 24 12 6.7 3.7 | 3.4 38.1 230 22 11 4.9 2.7
12500 4.4 39.9 185 23 12 6.2 3.4 | 4.1 39.4 225 21 11 4.8 2.6
12000 5.2 41.4 190 23 12 6.2 3.4 | 4.8 40.6 220 21 11 4.5 2.4
11750 5.6 42.1 190 22 11 6.4 3.5 | 5.1 41.2 220 20 10 3.6 2.0
11500 6.1 43.0 190 22 11 5.8 3.2 | 5.3 41.5 215 20 10 4.6 2.5
11250 6.4 43.5 195 21 11 5.4 2.9 | 5.7 42.3 215 19 10 5.8 3.2
11000 6.8 44.2 195 20 10 5.1 2.8 | 6.1 43.0 210 19 10 5.1 2.8
10750 7.2 45.0 195 19 10 6.6 3.6 | 6.5 43.7 210 18 10 6.7 3.7
10500 7.6 45.7 195 18 9 4.1 2.2 | 7.1 44.8 205 18 9 6.7 3.7
10250 7.7 45.9 195 17 9 0.8 0.5 | 7.4 45.3 205 17 9 5.2 2.8
10000 7.8 46.0 195 15 8 1.5 0.8 | 7.8 46.0 205 15 8 5.7 3.1
9750 7.9 46.2 200 14 7 2.1 1.1 | 8.1 46.6 210 13 7 5.3 2.9
9500 8.2 46.8 200 12 6 4.7 2.6 | 8.6 47.5 210 12 6 10.8 5.9
9250 8.6 47.5 205 8 4 6.4 3.5 | 9.7 49.5 210 10 5 20.4 11.2
9000 9.1 48.4 225 4 2 4.2 2.3 | 10.9 51.6 210 9 4 3.2 1.7
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
10/10/2025 at 1500 MDT | 10/10/2025 at 1800 MDT
|
CAPE... +237.7 LI... -1.3 | CAPE... +303.6 LI... -1.4
CINH... -0.6 K Index... +26.1 | CINH... -0.9 K Index... +24.7
|
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 -68.0 -90.4 265 45 23 4.8 2.7 | -68.5 -91.3 260 44 22 5.1 2.8
45000 -59.8 -75.6 265 59 30 6.6 3.6 | -59.8 -75.6 260 61 32 6.4 3.5
40000 -49.9 -57.8 260 67 34 6.3 3.5 | -50.3 -58.5 260 70 36 5.8 3.2
38000 -46.1 -51.0 260 64 33 6.3 3.5 | -46.8 -52.2 260 62 32 5.8 3.2
36000 -42.3 -44.1 260 62 32 6.4 3.5 | -43.3 -45.9 260 54 28 5.6 3.1
34000 -38.9 -38.0 250 50 26 5.7 3.1 | -38.9 -38.0 255 42 22 7.6 4.2
32000 -35.0 -31.0 240 37 19 6.6 3.6 | -33.7 -28.7 255 29 15 8.4 4.6
30000 -30.0 -22.0 235 35 18 8.6 4.7 | -28.9 -20.0 250 30 15 8.1 4.4
29000 -27.5 -17.5 235 35 18 8.6 4.7 | -26.5 -15.7 250 30 16 8.1 4.5
28000 -25.0 -13.0 235 35 18 7.6 4.2 | -24.2 -11.6 245 31 16 7.4 4.1
27000 -22.7 -8.9 235 33 17 7.6 4.2 | -22.0 -7.6 245 32 16 7.3 4.0
26000 -20.5 -4.9 235 32 16 7.6 4.2 | -19.8 -3.6 240 32 17 7.4 4.0
25000 -18.2 -0.8 230 30 15 7.5 4.1 | -17.7 0.1 240 33 17 7.2 4.0
24000 -16.1 3.0 230 29 15 7.2 3.9 | -15.7 3.7 235 32 16 6.4 3.5
23000 -14.0 6.8 235 28 14 7.2 3.9 | -13.9 7.0 230 31 16 6.4 3.5
22000 -11.8 10.8 235 27 14 6.7 3.7 | -12.0 10.4 225 30 15 6.3 3.5
21000 -10.2 13.6 235 25 13 5.7 3.1 | -10.3 13.5 220 28 14 5.9 3.3
20000 -8.5 16.7 235 23 12 5.8 3.2 | -8.6 16.5 215 25 13 6.0 3.3
19500 -7.7 18.1 230 22 11 5.8 3.2 | -7.7 18.1 215 25 13 6.0 3.3
19000 -6.9 19.6 230 21 11 5.5 3.0 | -6.8 19.8 210 24 12 5.9 3.3
18500 -6.1 21.0 230 19 10 5.6 3.1 | -6.0 21.2 210 24 12 5.9 3.3
18000 -5.3 22.5 230 17 9 5.7 3.1 | -5.1 22.8 210 23 12 5.8 3.2
17500 -4.5 23.9 230 16 8 5.9 3.3 | -4.3 24.3 215 23 12 5.5 3.0
17000 -3.6 25.5 235 14 7 6.0 3.3 | -3.5 25.7 215 23 12 5.6 3.1
16500 -2.7 27.1 240 12 6 6.0 3.3 | -2.8 27.0 215 23 12 5.1 2.8
16000 -1.9 28.6 245 11 6 6.0 3.3 | -2.0 28.4 215 22 11 5.1 2.8
15500 -1.0 30.2 250 10 5 6.3 3.5 | -1.3 29.7 215 21 11 4.7 2.6
15000 -0.0 32.0 255 10 5 6.4 3.5 | -0.4 31.3 215 20 10 4.4 2.4
14500 0.9 33.6 255 9 5 5.3 2.9 | 0.3 32.5 215 18 9 5.8 3.2
14000 1.8 35.2 255 9 5 7.5 4.1 | 1.2 34.2 215 17 9 6.5 3.6
13500 3.3 37.9 250 9 5 8.6 4.7 | 2.2 36.0 215 16 8 8.1 4.4
13000 4.4 39.9 240 11 6 5.5 3.0 | 3.3 37.9 210 15 8 7.1 3.9
12500 5.2 41.4 235 13 7 5.7 3.1 | 4.4 39.9 210 14 7 7.0 3.9
12000 6.0 42.8 225 12 6 5.7 3.1 | 5.3 41.5 210 13 7 6.4 3.5
11750 6.3 43.3 220 11 6 5.1 2.8 | 5.7 42.3 210 12 6 5.7 3.1
11500 6.7 44.1 210 11 6 6.7 3.7 | 6.1 43.0 215 11 6 5.6 3.1
11250 7.3 45.1 210 11 5 8.6 4.7 | 6.5 43.7 215 10 5 5.4 3.0
11000 7.9 46.2 205 10 5 7.3 4.0 | 6.9 44.4 220 9 5 5.3 2.9
10750 8.5 47.3 205 10 5 10.8 5.9 | 7.3 45.1 225 8 4 5.9 3.3
10500 9.4 48.9 200 10 5 11.9 6.5 | 7.7 45.9 230 8 4 6.6 3.6
10250 10.1 50.2 200 9 5 9.3 5.1 | 8.2 46.8 235 7 3 6.3 3.4
10000 10.8 51.4 200 9 5 9.8 5.4 | 8.6 47.5 245 6 3 6.4 3.5
9750 11.6 52.9 200 9 5 10.2 5.6 | 9.0 48.2 255 5 3 6.2 3.4
9500 12.5 54.5 200 9 4 15.5 8.5 | 9.5 49.1 275 5 2 8.3 4.5
9250 13.9 57.0 200 8 4 22.2 12.2 | 10.2 50.4 290 4 2 12.3 6.7
9000 15.3 59.5 200 7 4 11.0 6.0 | 11.0 51.8 315 3 1 5.6 3.1
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