Soaring Guidance
Issued by NWS Pueblo, CO
Issued by NWS Pueblo, CO
153
UXUS97 KPUB 241239
SRGPUB
Soaring Forecast
National Weather Service Pueblo, Colorado
0639 MDT Saturday, May 24, 2025
This forecast is for Villa Grove, CO for Saturday, May 24, 2025:
If the trigger temperature of 61.2 F/16.2 C is reached...then
Thermal Soaring Index....................... Excellent
Maximum rate of lift........................ 1434 ft/min (7.3 m/s)
Maximum height of thermals.................. 24325 ft MSL (15326 ft AGL)
Forecast maximum temperature................... 75.0 F/24.3 C
Time of trigger temperature.................... 0930 MDT
Time of overdevelopment........................ None
Middle/high clouds during soaring window....... Overcast thin high
Surface winds during soaring window............ 20 mph or less
Height of the -3 thermal index................. 20631 ft MSL (11632 ft AGL)
Thermal soaring outlook for Sunday 05/25....... Good
Wave Soaring Index............................. Not available
Remarks...
Sunrise/Sunset.................... 05:45:30 / 20:15:28 MDT
Total possible sunshine........... 14 hr 29 min 58 sec (869 min 58 sec)
Altitude of sun at 13:00:29 MDT... 72.65 degrees
Upper air data from numerical model forecast valid on 05/24/2025 at 0600 MDT
Freezing level.................. 14492 ft MSL (5493 ft AGL)
Convective condensation level... 23646 ft MSL (14647 ft AGL)
Lifted condensation level....... 24169 ft MSL (15170 ft AGL)
Lifted index.................... -1.1
K index......................... -7.2
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 -63.7 -82.7 255 39 20 1.3 0.7 74.6 166.2 30.5 M M
45000 -61.8 -79.2 255 47 24 1.4 0.7 55.9 132.6 20.5 M M
40000 -59.7 -75.5 255 66 34 3.2 1.8 36.2 97.2 8.5 M M
38000 -55.4 -67.7 255 64 33 7.3 4.0 33.6 92.4 6.9 M M
36000 -51.0 -59.8 255 61 31 7.3 4.0 31.7 89.1 5.7 M M
34000 -46.5 -51.7 255 57 29 7.7 4.2 29.9 85.9 4.5 M M
32000 -41.9 -43.4 255 51 26 7.7 4.2 28.4 83.0 3.4 M M
30000 -37.3 -35.1 255 46 24 7.7 4.2 26.8 80.2 2.3 M M
29000 -34.5 -30.1 255 43 22 7.7 4.2 25.8 78.5 1.5 M M
28000 -32.2 -26.0 250 41 21 7.6 4.1 25.2 77.3 1.0 M M
27000 -29.6 -21.3 250 40 21 9.0 4.9 24.7 76.5 0.7 M M
26000 -26.9 -16.4 250 39 20 9.0 4.9 24.4 75.9 0.4 M M
25000 -24.2 -11.6 250 39 20 9.0 4.9 24.2 75.5 0.2 M M
24000 -21.8 -7.2 250 37 19 7.3 4.0 23.5 74.4 -0.3 1501 7.6
23000 -19.6 -3.3 245 35 18 7.2 4.0 22.6 72.7 -1.1 1407 7.1
22000 -17.5 0.5 245 34 17 7.2 4.0 21.8 71.2 -1.8 1312 6.7
21000 -15.3 4.5 240 31 16 7.1 3.9 20.9 69.6 -2.6 1219 6.2
20000 -13.2 8.2 240 29 15 7.1 3.9 20.0 68.0 -3.5 1126 5.7
19500 -12.2 10.0 235 28 14 7.2 3.9 19.6 67.2 -3.9 1079 5.5
19000 -11.1 12.0 235 26 14 7.1 3.9 19.2 66.6 -4.3 1033 5.2
18500 -10.1 13.8 235 24 12 7.0 3.9 18.7 65.7 -4.7 987 5.0
18000 -9.0 15.8 240 22 11 7.1 3.9 18.3 64.9 -5.2 942 4.8
17500 -8.0 17.6 245 20 10 7.6 4.2 17.9 64.2 -5.6 895 4.5
17000 -6.9 19.6 250 18 10 7.7 4.2 17.5 63.6 -6.0 847 4.3
16500 -5.8 21.6 255 17 9 8.3 4.6 17.2 63.0 -6.4 799 4.1
16000 -4.4 24.1 260 18 9 9.0 4.9 17.1 62.8 -6.5 744 3.8
15500 -2.4 27.7 260 19 10 8.6 4.7 16.9 62.5 -6.8 662 3.4
15000 -1.1 30.0 260 20 10 8.2 4.5 16.7 62.1 -7.0 609 3.1
14500 0.3 32.5 255 20 10 11.4 6.2 16.7 62.1 -7.0 551 2.8
14000 1.8 35.2 255 21 11 9.1 5.0 16.8 62.2 -7.0 491 2.5
13500 3.2 37.8 250 21 11 8.1 4.4 16.7 62.1 -7.1 434 2.2
13000 4.5 40.1 250 20 10 9.5 5.2 16.5 61.6 -7.4 382 1.9
12500 5.8 42.4 245 18 9 9.2 5.1 16.4 61.5 -7.5 326 1.7
12000 7.2 45.0 240 16 8 7.9 4.4 16.3 61.3 -7.7 271 1.4
11750 7.7 45.9 235 14 7 7.0 3.8 16.1 60.9 -7.9 248 1.3
11500 8.2 46.8 230 13 6 7.5 4.1 15.9 60.6 -8.1 224 1.1
11250 8.8 47.8 225 11 6 6.0 3.3 15.7 60.2 -8.3 201 1.0
11000 9.1 48.4 220 10 5 4.9 2.7 15.3 59.5 -8.7 183 0.9
10750 9.5 49.1 215 9 5 3.5 1.9 14.9 58.9 -9.1 166 0.8
10500 9.6 49.3 210 8 4 3.0 1.7 14.4 57.9 -9.7 153 0.8
10250 9.8 49.6 205 7 4 -0.1 -0.1 13.8 56.9 -10.3 140 0.7
10000 9.6 49.3 200 7 4 -3.9 -2.2 12.9 55.2 -11.3 140 0.7
9750 9.3 48.7 200 6 3 -4.1 -2.2 11.9 53.3 -12.3 142 0.7
9500 8.9 48.0 200 6 3 -6.0 -3.3 10.7 51.3 -13.5 146 0.7
9250 8.1 46.6 200 5 3 -16.8 -9.2 9.3 48.7 -15.0 161 0.8
9000 5.2 41.4 200 4 2 -70.9 -38.9 5.7 42.2 -18.7 241 1.2
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 * * * * * *
05/24/2025 at 0900 MDT | 05/24/2025 at 1200 MDT
|
CAPE... 0.0 LI... +2.5 | CAPE... +0.9 LI... +0.8
CINH... -0.7 K Index... -15.3 | CINH... 0.0 K Index... +4.7
|
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 -63.3 -81.9 255 38 19 0.6 0.3 | -62.5 -80.5 250 36 19 -0.1 -0.0
45000 -62.3 -80.1 245 45 23 1.4 0.8 | -62.4 -80.3 240 49 25 1.5 0.8
40000 -60.0 -76.0 250 66 34 3.8 2.1 | -59.9 -75.8 245 62 32 3.4 1.9
38000 -55.6 -68.1 250 62 32 7.4 4.1 | -55.8 -68.4 245 63 32 7.0 3.9
36000 -51.2 -60.2 245 59 30 7.4 4.1 | -51.6 -60.9 245 63 33 7.0 3.9
34000 -46.6 -51.9 245 54 28 7.8 4.3 | -46.9 -52.4 245 61 31 8.5 4.7
32000 -42.0 -43.6 250 47 24 7.8 4.3 | -41.8 -43.2 250 57 29 8.6 4.7
30000 -37.3 -35.1 250 43 22 8.0 4.4 | -36.3 -33.3 245 50 26 7.8 4.3
29000 -34.3 -29.7 250 41 21 8.0 4.4 | -33.9 -29.0 245 47 24 7.8 4.3
28000 -31.9 -25.4 250 39 20 8.0 4.4 | -31.6 -24.9 245 43 22 7.8 4.3
27000 -29.3 -20.7 245 39 20 8.9 4.9 | -29.1 -20.4 245 42 22 8.4 4.6
26000 -26.7 -16.1 245 40 20 8.9 4.9 | -26.6 -15.9 240 42 22 8.4 4.6
25000 -24.0 -11.2 245 40 21 8.9 4.9 | -24.1 -11.4 240 42 21 8.4 4.6
24000 -21.4 -6.5 245 39 20 8.6 4.7 | -21.8 -7.2 240 40 21 7.3 4.0
23000 -18.8 -1.8 245 38 20 8.6 4.7 | -19.6 -3.3 245 38 20 7.3 4.0
22000 -16.2 2.8 245 37 19 8.8 4.8 | -17.4 0.7 245 36 19 7.3 4.0
21000 -14.2 6.4 245 34 18 5.8 3.2 | -15.4 4.3 245 32 17 6.3 3.4
20000 -12.5 9.5 245 31 16 5.8 3.2 | -13.6 7.5 250 27 14 6.3 3.5
19500 -11.6 11.1 240 30 15 5.8 3.2 | -12.7 9.1 250 25 13 6.4 3.5
19000 -10.7 12.7 240 28 14 5.5 3.0 | -11.8 10.8 255 23 12 7.1 3.9
18500 -10.0 14.0 240 26 14 5.1 2.8 | -10.6 12.9 255 22 11 8.1 4.4
18000 -9.2 15.4 240 25 13 4.9 2.7 | -9.4 15.1 250 20 10 8.1 4.4
17500 -8.3 17.1 240 24 12 7.6 4.2 | -8.1 17.4 250 19 10 8.5 4.7
17000 -7.2 19.0 240 22 12 7.6 4.2 | -6.9 19.6 245 18 9 8.5 4.7
16500 -6.1 21.0 240 21 11 8.4 4.6 | -5.6 21.9 245 17 9 8.9 4.9
16000 -4.8 23.4 240 21 11 9.1 5.0 | -3.5 25.7 240 16 8 9.4 5.2
15500 -2.8 27.0 245 20 10 8.7 4.8 | -2.1 28.2 235 16 8 8.5 4.7
15000 -1.5 29.3 245 20 10 8.2 4.5 | -0.9 30.4 230 15 8 7.8 4.3
14500 -0.0 32.0 245 19 10 11.8 6.5 | 0.5 32.9 225 15 8 11.2 6.1
14000 1.5 34.7 245 19 10 9.3 5.1 | 2.0 35.6 220 14 7 9.0 4.9
13500 2.9 37.2 245 19 10 7.7 4.2 | 3.3 37.9 215 14 7 8.5 4.7
13000 4.1 39.4 245 17 9 9.4 5.1 | 4.7 40.5 210 14 7 9.7 5.3
12500 5.4 41.7 250 15 8 9.0 5.0 | 6.1 43.0 205 14 7 9.3 5.1
12000 6.5 43.7 250 12 6 6.3 3.4 | 7.6 45.7 200 14 7 10.3 5.7
11750 7.0 44.6 245 11 5 6.0 3.3 | 8.3 46.9 200 14 7 8.7 4.8
11500 7.4 45.3 245 9 5 6.2 3.4 | 9.0 48.2 195 14 7 9.0 4.9
11250 7.9 46.2 240 7 4 5.7 3.1 | 9.6 49.3 195 14 7 9.6 5.3
11000 8.3 46.9 230 6 3 4.9 2.7 | 10.4 50.7 195 14 7 10.5 5.8
10750 8.7 47.7 225 5 3 6.2 3.4 | 11.2 52.2 190 14 7 9.8 5.4
10500 9.2 48.6 220 5 3 6.8 3.7 | 11.9 53.4 190 14 7 9.0 4.9
10250 9.7 49.5 210 5 2 7.8 4.3 | 12.6 54.7 190 14 7 10.2 5.6
10000 10.3 50.5 210 5 2 9.0 5.3 | 13.4 56.1 185 13 7 11.0 6.0
9750 11.0 51.8 205 4 2 9.0 4.9 | 14.2 57.6 185 13 7 11.6 6.4
9500 11.7 53.1 200 4 2 10.1 5.5 | 15.1 59.2 185 12 6 11.5 6.3
9250 12.6 54.7 200 4 2 15.9 8.7 | 16.1 61.0 185 11 6 19.1 10.5
9000 14.5 58.1 190 4 2 41.3 22.7 | M M M M M M M
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
05/24/2025 at 1500 MDT | 05/24/2025 at 1800 MDT
|
CAPE... +16.9 LI... -0.4 | CAPE... +30.7 LI... -0.1
CINH... -0.1 K Index... +4.0 | CINH... -1.8 K Index... +8.3
|
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 -61.1 -78.0 245 37 19 -0.7 -0.4 | -60.9 -77.6 250 33 17 -0.0 -0.0
45000 -61.8 -79.2 240 55 29 1.1 0.6 | -61.1 -78.0 245 57 29 -0.3 -0.2
40000 -60.2 -76.4 235 72 37 2.8 1.5 | -61.5 -78.7 235 74 38 1.8 1.0
38000 -55.9 -68.6 235 73 37 7.4 4.1 | -56.4 -69.5 230 70 36 9.1 5.0
36000 -51.5 -60.7 240 73 38 7.4 4.1 | -50.9 -59.6 225 67 34 9.1 5.0
34000 -46.7 -52.1 240 69 35 8.4 4.6 | -46.1 -51.0 230 60 31 7.3 4.0
32000 -41.6 -42.9 235 61 31 8.5 4.6 | -41.8 -43.2 240 53 27 7.3 4.0
30000 -36.4 -33.5 240 52 27 7.4 4.0 | -36.6 -33.9 245 47 24 8.0 4.4
29000 -34.2 -29.6 240 47 24 7.4 4.0 | -34.2 -29.6 240 44 23 8.0 4.4
28000 -32.0 -25.6 240 43 22 7.4 4.1 | -31.8 -25.2 240 42 22 8.1 4.4
27000 -29.8 -21.6 245 40 20 7.2 4.0 | -29.5 -21.1 240 38 19 7.5 4.1
26000 -27.7 -17.9 245 36 19 7.3 4.0 | -27.3 -17.1 240 33 17 7.5 4.1
25000 -25.5 -13.9 250 34 17 7.3 4.0 | -25.0 -13.0 240 29 15 7.5 4.1
24000 -23.2 -9.8 255 31 16 8.0 4.4 | -22.9 -9.2 240 25 13 7.0 3.9
23000 -20.9 -5.6 255 28 15 8.0 4.4 | -20.8 -5.4 235 21 11 7.1 3.9
22000 -18.5 -1.3 255 26 13 7.9 4.4 | -18.8 -1.8 235 18 9 7.1 3.9
21000 -15.9 3.4 250 24 12 9.1 5.0 | -16.3 2.7 240 17 9 9.0 4.9
20000 -13.1 8.4 245 23 12 9.1 5.0 | -13.6 7.5 245 18 9 9.0 5.0
19500 -11.8 10.8 240 22 12 9.1 5.0 | -12.3 9.9 245 18 9 9.0 5.0
19000 -10.4 13.3 240 22 11 9.3 5.1 | -10.9 12.4 245 18 9 9.1 5.0
18500 -9.0 15.8 235 22 11 9.5 5.2 | -9.5 14.9 245 19 10 9.2 5.0
18000 -7.6 18.3 235 22 11 9.5 5.2 | -8.2 17.2 250 19 10 9.2 5.0
17500 -6.1 21.0 230 22 11 9.6 5.3 | -6.8 19.8 250 19 10 9.3 5.1
17000 -4.7 23.5 230 22 11 9.6 5.3 | -4.7 23.5 250 20 10 9.3 5.1
16500 -3.3 26.1 230 22 11 9.5 5.2 | -3.3 26.1 250 20 10 9.5 5.2
16000 -1.1 30.0 225 23 12 9.4 5.2 | -1.9 28.6 250 21 11 9.5 5.2
15500 0.3 32.5 220 23 12 8.9 4.9 | -0.5 31.1 250 21 11 9.0 4.9
15000 1.6 34.9 220 23 12 8.2 4.5 | 0.8 33.4 250 21 11 8.5 4.7
14500 3.1 37.6 215 23 12 11.7 6.4 | 2.3 36.1 250 22 11 10.6 5.8
14000 4.5 40.1 215 23 12 9.0 5.0 | 3.7 38.7 250 22 12 9.3 5.1
13500 5.9 42.6 210 24 12 9.9 5.4 | 5.1 41.2 250 23 12 10.0 5.5
13000 7.4 45.3 205 24 12 9.3 5.1 | 6.6 43.9 250 23 12 9.1 5.0
12500 8.8 47.8 205 24 12 9.4 5.2 | 8.0 46.4 250 24 12 9.0 4.9
12000 10.3 50.5 200 24 12 10.0 5.5 | 9.5 49.1 250 24 12 10.3 5.7
11750 11.0 51.8 200 24 13 9.6 5.3 | 10.2 50.4 250 24 12 8.6 4.7
11500 11.7 53.1 200 24 13 9.6 5.3 | 10.8 51.4 250 24 12 8.8 4.8
11250 12.4 54.3 195 24 13 9.8 5.4 | 11.5 52.7 250 24 13 9.7 5.3
11000 13.2 55.8 195 24 13 10.2 5.6 | 12.3 54.1 250 24 12 11.1 6.1
10750 14.0 57.2 195 24 12 10.2 5.6 | 13.1 55.6 250 24 12 10.1 5.5
10500 14.7 58.5 195 24 12 10.2 5.6 | 13.8 56.8 250 24 12 9.1 5.0
10250 15.5 59.9 190 24 12 10.5 5.8 | 14.5 58.1 250 23 12 9.8 5.4
10000 16.3 61.3 190 23 12 10.8 5.9 | 15.3 59.5 250 23 12 10.5 5.7
9750 17.1 62.8 190 23 12 11.6 6.3 | 16.1 61.0 250 22 11 10.7 5.9
9500 18.0 64.4 190 21 11 11.5 6.3 | 16.8 62.2 250 20 10 10.4 5.7
9250 19.0 66.2 190 19 10 18.3 10.0 | 17.6 63.7 250 18 9 12.2 6.7
9000 21.7 71.1 185 16 8 67.6 37.1 | M M M M M M M
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