Soaring Guidance
Issued by NWS Pueblo, CO
Issued by NWS Pueblo, CO
021
UXUS97 KPUB 201206
SRGPUB
Soaring Forecast
National Weather Service Pueblo, Colorado
0606 MDT Monday, May 20, 2024
This forecast is for Villa Grove, CO for Monday, May 20, 2024:
If the trigger temperature of 56.4 F/13.6 C is reached...then
Thermal Soaring Index....................... Good
Maximum rate of lift........................ 1386 ft/min (7.0 m/s)
Maximum height of thermals.................. 24827 ft MSL (15865 ft AGL)
Forecast maximum temperature................... 71.0 F/22.1 C
Time of trigger temperature.................... 0930 MDT
Time of overdevelopment........................ 1700 MDT
Middle/high clouds during soaring window....... Broken/overcast thin middle
Surface winds during soaring window............ Between 20 mph and 30 mph
Height of the -3 thermal index................. 20491 ft MSL (11529 ft AGL)
Thermal soaring outlook for Tuesday 05/21...... Good
Wave Soaring Index............................. Not available
Remarks...
Sunrise/Sunset.................... 05:47:56 / 20:12:24 MDT
Total possible sunshine........... 14 hr 24 min 28 sec (864 min 28 sec)
Altitude of sun at 13:00:10 MDT... 71.93 degrees
Upper air data from numerical model forecast valid on 05/20/2024 at 0600 MDT
Freezing level.................. 13559 ft MSL (4597 ft AGL)
Convective condensation level... 19675 ft MSL (10713 ft AGL)
Lifted condensation level....... 21516 ft MSL (12553 ft AGL)
Lifted index.................... -1.6
K index......................... +3.8
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 -56.8 -70.2 250 54 28 0.6 0.3 M M M M M
45000 -55.8 -68.4 255 68 35 0.7 0.4 M M M M M
40000 -54.8 -66.6 260 88 45 0.2 0.1 M M M M M
38000 -52.1 -61.8 260 87 45 4.9 2.7 M M M M M
36000 -49.2 -56.6 260 85 44 4.9 2.7 M M M M M
34000 -45.7 -50.3 260 82 42 6.9 3.8 M M M M M
32000 -41.6 -42.9 260 76 39 6.9 3.8 M M M M M
30000 -37.4 -35.3 260 67 34 7.0 3.8 27.4 81.3 4.5 M M
29000 -34.8 -30.6 255 59 31 7.0 3.8 26.1 78.9 3.5 M M
28000 -32.7 -26.9 255 54 28 7.0 3.8 25.1 77.3 2.8 M M
27000 -30.6 -23.1 250 50 26 6.6 3.6 24.1 75.3 2.0 M M
26000 -28.6 -19.5 250 47 24 6.6 3.6 22.9 73.1 1.0 M M
25000 -26.7 -16.1 250 45 23 6.6 3.6 21.8 71.2 0.1 M M
24000 -24.5 -12.1 250 43 22 8.3 4.5 20.9 69.6 -0.7 1503 7.6
23000 -22.1 -7.8 250 41 21 8.1 4.5 20.3 68.5 -1.2 1401 7.1
22000 -19.7 -3.5 250 39 20 8.1 4.4 19.7 67.5 -1.7 1298 6.6
21000 -17.5 0.5 250 37 19 6.4 3.5 18.9 66.1 -2.4 1203 6.1
20000 -15.6 3.9 245 33 17 6.4 3.5 17.8 64.0 -3.5 1116 5.7
19500 -14.6 5.7 245 31 16 6.5 3.5 17.2 63.0 -4.0 1073 5.5
19000 -13.7 7.3 245 29 15 6.6 3.6 16.7 62.1 -4.5 1030 5.2
18500 -12.9 8.8 240 26 14 4.0 2.2 16.0 60.8 -5.3 993 5.0
18000 -12.4 9.7 240 22 11 4.5 2.5 15.1 59.1 -6.2 962 4.9
17500 -11.7 10.9 240 18 9 7.8 4.3 14.3 57.8 -7.1 928 4.7
17000 -10.3 13.5 245 18 9 9.5 5.2 14.3 57.7 -7.1 870 4.4
16500 -8.9 16.0 245 18 9 9.6 5.3 14.3 57.7 -7.2 812 4.1
16000 -7.4 18.7 245 18 9 9.7 5.3 14.3 57.7 -7.3 754 3.8
15500 -6.0 21.2 245 18 9 9.6 5.3 14.2 57.6 -7.3 696 3.5
15000 -4.5 23.9 245 18 9 10.5 5.8 14.3 57.7 -7.3 636 3.2
14500 -2.9 26.8 250 17 9 10.7 5.8 14.4 57.9 -7.2 575 2.9
14000 -0.9 30.4 250 17 9 10.2 5.6 14.2 57.5 -7.5 494 2.5
13500 0.5 32.9 250 17 9 10.1 5.5 14.1 57.5 -7.6 436 2.2
13000 1.8 35.2 250 16 8 7.8 4.3 14.0 57.1 -7.8 382 1.9
12500 3.1 37.6 245 16 8 9.0 4.9 13.8 56.8 -8.0 329 1.7
12000 4.2 39.6 240 16 8 6.1 3.3 13.4 56.2 -8.4 281 1.4
11750 4.7 40.5 240 15 8 7.2 3.9 13.2 55.8 -8.6 258 1.3
11500 5.2 41.4 235 14 7 7.4 4.1 13.0 55.4 -8.9 235 1.2
11250 5.8 42.4 235 14 7 6.4 3.5 12.8 55.1 -9.1 211 1.1
11000 6.1 43.0 230 13 7 4.1 2.3 12.5 54.4 -9.4 193 1.0
10750 6.4 43.5 225 11 6 3.8 2.1 12.0 53.6 -9.9 177 0.9
10500 6.7 44.1 220 10 5 4.5 2.5 11.6 52.8 -10.4 161 0.8
10250 7.0 44.6 215 9 5 3.1 1.7 11.2 52.1 -10.8 144 0.7
10000 7.1 44.8 205 8 4 0.9 0.5 10.5 51.0 -11.5 134 0.7
9750 7.1 44.8 200 8 4 -0.6 -0.3 9.8 49.7 -12.2 126 0.6
9500 7.0 44.6 195 8 4 -3.6 -2.0 8.9 48.1 -13.2 124 0.6
9250 6.3 43.3 190 8 4 -15.8 -8.7 7.6 45.7 -14.6 136 0.7
9000 3.7 38.7 230 3 2 -62.1 -34.1 4.3 39.7 -18.0 207 1.1
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 * * * * * *
05/20/2024 at 0900 MDT | 05/20/2024 at 1200 MDT
|
CAPE... 0.0 LI... +2.9 | CAPE... +6.4 LI... +2.4
CINH... 0.0 K Index... -5.5 | CINH... -29.6 K Index... -3.4
|
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 -57.3 -71.1 250 51 26 1.4 0.8 | -56.7 -70.1 250 51 26 1.4 0.8
45000 -55.4 -67.7 250 60 31 0.5 0.3 | -54.9 -66.8 245 66 34 0.2 0.1
40000 -54.6 -66.3 255 90 46 0.1 0.0 | -54.6 -66.3 250 96 49 -0.2 -0.1
38000 -52.0 -61.6 255 94 48 4.9 2.7 | -52.0 -61.6 250 99 51 5.0 2.8
36000 -49.1 -56.4 255 97 50 4.9 2.7 | -49.0 -56.2 250 101 52 5.0 2.8
34000 -45.7 -50.3 255 95 49 6.7 3.7 | -45.4 -49.7 250 99 51 6.8 3.7
32000 -41.7 -43.1 255 87 45 6.7 3.7 | -41.4 -42.5 250 94 48 6.8 3.7
30000 -37.5 -35.5 255 80 41 7.2 3.9 | -37.3 -35.1 250 87 45 6.8 3.7
29000 -34.8 -30.6 255 75 39 7.2 3.9 | -34.7 -30.5 250 80 41 6.8 3.7
28000 -32.7 -26.9 255 71 37 7.2 3.9 | -32.7 -26.9 250 74 38 6.8 3.7
27000 -30.7 -23.3 255 67 34 6.2 3.4 | -30.7 -23.3 250 69 35 6.6 3.6
26000 -28.8 -19.8 255 61 31 6.2 3.4 | -28.7 -19.7 250 63 32 6.6 3.6
25000 -27.0 -16.6 255 55 28 6.3 3.5 | -26.7 -16.1 250 57 30 6.6 3.6
24000 -24.9 -12.8 255 50 26 9.1 5.0 | -24.6 -12.3 250 51 26 8.7 4.8
23000 -22.2 -8.0 250 47 24 9.0 4.9 | -22.0 -7.6 245 43 22 8.6 4.7
22000 -19.5 -3.1 250 45 23 8.9 4.9 | -19.5 -3.1 240 35 18 8.6 4.7
21000 -17.0 1.4 245 43 22 7.2 3.9 | -16.9 1.6 235 34 17 8.4 4.6
20000 -14.9 5.2 245 42 22 7.2 3.9 | -14.4 6.1 240 38 20 8.4 4.6
19500 -13.8 7.2 245 42 22 7.2 3.9 | -13.1 8.4 245 41 21 8.4 4.6
19000 -12.7 9.1 245 42 21 7.2 3.9 | -11.9 10.6 245 43 22 8.4 4.6
18500 -11.6 11.1 245 41 21 7.9 4.4 | -10.7 12.7 245 44 22 6.6 3.6
18000 -10.4 13.3 245 40 21 7.9 4.3 | -9.7 14.5 245 43 22 6.8 3.7
17500 -9.2 15.4 245 39 20 5.6 3.1 | -8.7 16.3 245 42 22 6.4 3.5
17000 -8.6 16.5 245 36 18 4.5 2.5 | -7.8 18.0 240 39 20 6.3 3.4
16500 -8.0 17.6 240 33 17 4.9 2.7 | -6.9 19.6 240 37 19 6.3 3.4
16000 -7.2 19.0 235 30 15 7.1 3.9 | -6.0 21.2 240 34 18 6.0 3.3
15500 -6.2 20.8 235 27 14 6.9 3.8 | -5.1 22.8 235 32 16 6.0 3.3
15000 -5.0 23.0 230 24 12 9.8 5.4 | -4.2 24.4 235 29 15 7.2 3.9
14500 -2.9 26.8 225 20 10 7.0 3.8 | -3.2 26.2 230 26 14 7.3 4.0
14000 -1.8 28.8 225 18 9 9.9 5.4 | -1.6 29.1 225 23 12 8.4 4.6
13500 -0.4 31.3 225 16 8 9.4 5.1 | -0.4 31.3 220 22 11 7.9 4.3
13000 1.0 33.8 225 14 7 8.9 4.9 | 1.0 33.8 215 21 11 10.5 5.8
12500 2.3 36.1 235 14 7 8.9 4.9 | 2.4 36.3 210 21 11 10.3 5.6
12000 3.6 38.5 240 13 7 8.4 4.6 | 3.7 38.7 210 20 10 8.6 4.7
11750 4.2 39.6 245 13 7 8.8 4.8 | 4.5 40.1 210 20 10 11.3 6.2
11500 4.9 40.8 245 13 7 9.1 5.0 | 5.3 41.5 210 20 10 10.9 6.0
11250 5.5 41.9 250 13 7 7.8 4.3 | 6.1 43.0 210 20 10 10.7 5.9
11000 6.0 42.8 250 12 6 5.5 3.0 | 6.9 44.4 210 20 10 9.9 5.4
10750 6.4 43.5 245 12 6 4.5 2.5 | 7.6 45.7 210 20 10 9.8 5.3
10500 6.7 44.1 245 11 6 3.9 2.1 | 8.3 46.9 210 20 10 9.7 5.3
10250 7.0 44.6 240 10 5 4.9 2.7 | 9.1 48.4 210 19 10 10.2 5.6
10000 7.4 45.3 235 9 5 6.3 3.5 | 9.9 49.8 205 19 10 11.3 6.2
9750 7.9 46.2 230 8 4 7.3 4.0 | 10.7 51.3 205 19 10 12.3 6.7
9500 8.4 47.1 220 7 4 8.9 4.9 | 11.6 52.9 205 18 9 11.1 6.1
9250 9.3 48.7 215 7 3 15.5 8.5 | 12.6 54.7 205 17 9 18.3 10.0
9000 11.2 52.2 210 6 3 41.9 23.0 | 15.6 60.1 205 14 7 76.3 41.9
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
05/20/2024 at 1500 MDT | 05/20/2024 at 1800 MDT
|
CAPE... +4.6 LI... +1.3 | CAPE... 0.0 LI... +0.8
CINH... -18.0 K Index... +10.1 | CINH... 0.0 K Index... +9.0
|
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 -56.4 -69.5 240 54 28 1.8 1.0 | -54.9 -66.8 240 51 26 2.7 1.5
45000 -54.2 -65.6 235 71 37 -0.4 -0.2 | -51.4 -60.5 240 69 35 -1.5 -0.8
40000 -54.9 -66.8 245 101 52 -1.0 -0.6 | -54.0 -65.2 235 91 47 -1.7 -1.0
38000 -52.4 -62.3 245 105 54 4.9 2.7 | -52.4 -62.3 240 99 51 3.7 2.1
36000 -49.5 -57.1 245 109 56 4.9 2.7 | -50.1 -58.2 240 106 55 3.7 2.1
34000 -46.1 -51.0 240 110 56 6.7 3.7 | -47.4 -53.3 240 107 55 5.8 3.2
32000 -42.1 -43.8 245 106 54 6.7 3.7 | -44.0 -47.2 240 96 49 5.8 3.2
30000 -38.1 -36.6 245 101 52 6.8 3.7 | -39.9 -39.8 240 83 43 8.9 4.9
29000 -36.1 -33.0 245 97 50 6.8 3.7 | -36.5 -33.7 235 73 37 8.9 4.9
28000 -33.5 -28.3 245 93 48 6.9 3.8 | -33.9 -29.0 230 64 33 8.9 4.9
27000 -31.4 -24.5 245 86 44 7.5 4.1 | -31.3 -24.3 230 59 31 8.8 4.8
26000 -29.1 -20.4 245 76 39 7.5 4.1 | -28.6 -19.5 225 59 30 8.8 4.8
25000 -26.9 -16.4 245 66 34 7.5 4.1 | -26.0 -14.8 225 58 30 8.8 4.8
24000 -24.6 -12.3 245 57 29 7.2 4.0 | -23.6 -10.5 225 57 29 6.8 3.7
23000 -22.5 -8.5 240 51 26 7.3 4.0 | -21.5 -6.7 225 53 27 6.9 3.8
22000 -20.3 -4.5 235 45 23 7.5 4.1 | -19.5 -3.1 225 50 26 6.9 3.8
21000 -18.0 -0.4 235 43 22 8.9 4.9 | -17.7 0.1 230 47 24 4.5 2.5
20000 -15.3 4.5 235 46 24 8.9 4.9 | -16.3 2.7 240 48 25 4.7 2.6
19500 -14.0 6.8 240 47 24 8.9 4.9 | -15.6 3.9 240 49 25 4.7 2.6
19000 -12.6 9.3 240 49 25 9.0 4.9 | -14.9 5.2 245 51 26 4.6 2.5
18500 -11.3 11.7 240 49 25 8.1 4.5 | -14.1 6.6 250 51 26 6.0 3.3
18000 -10.1 13.8 240 49 25 8.2 4.5 | -13.2 8.2 250 49 25 6.1 3.4
17500 -8.8 16.2 240 48 25 7.7 4.2 | -12.3 9.9 250 47 24 7.2 3.9
17000 -7.7 18.1 235 46 24 7.3 4.0 | -10.9 12.4 250 46 24 9.6 5.3
16500 -6.6 20.1 230 43 22 7.2 4.0 | -9.5 14.9 250 46 23 9.6 5.3
16000 -5.6 21.9 230 40 21 6.9 3.8 | -8.0 17.6 250 45 23 9.1 5.0
15500 -4.6 23.7 220 37 19 6.8 3.7 | -6.7 19.9 250 45 23 9.1 5.0
15000 -3.4 25.9 215 35 18 10.2 5.6 | -5.2 22.6 250 44 23 10.3 5.6
14500 -1.9 28.6 215 32 17 10.0 5.5 | -2.9 26.8 250 42 22 6.0 3.3
14000 -0.7 30.7 210 31 16 8.0 4.4 | -2.1 28.2 245 40 21 8.3 4.6
13500 1.4 34.5 210 31 16 9.8 5.4 | -0.9 30.4 240 38 20 8.3 4.6
13000 2.9 37.2 210 31 16 10.0 5.5 | 0.1 32.2 235 37 19 6.2 3.4
12500 4.4 39.9 210 30 16 10.1 5.5 | 1.1 34.0 230 37 19 7.3 4.0
12000 5.7 42.3 210 30 16 9.2 5.1 | 2.1 35.8 220 38 19 7.0 3.9
11750 6.5 43.7 210 30 15 11.2 6.1 | 2.7 36.9 220 38 19 9.0 4.9
11500 7.3 45.1 210 30 15 10.7 5.9 | 3.4 38.1 220 37 19 8.9 4.9
11250 8.1 46.6 210 30 15 10.5 5.8 | 4.1 39.4 220 37 19 9.0 4.9
11000 8.9 48.0 210 30 15 8.5 4.7 | 4.7 40.5 215 37 19 8.4 4.6
10750 9.5 49.1 210 29 15 9.7 5.3 | 5.3 41.5 215 36 19 9.4 5.2
10500 10.3 50.5 210 29 15 11.7 6.4 | 6.1 43.0 215 35 18 10.7 5.8
10250 11.2 52.2 210 29 15 11.1 6.1 | 6.9 44.4 215 35 18 10.3 5.7
10000 12.0 53.6 205 28 15 10.7 5.9 | 7.6 45.7 215 34 17 9.7 5.3
9750 12.8 55.0 205 28 14 11.1 6.1 | 8.3 46.9 215 32 17 9.2 5.1
9500 13.6 56.5 205 27 14 11.1 6.1 | 9.0 48.2 215 30 16 9.4 5.1
9250 14.6 58.3 205 25 13 18.0 9.9 | 9.7 49.5 215 27 14 10.4 5.7
9000 17.3 63.1 205 20 10 69.1 37.9 | 10.7 51.3 210 19 10 19.3 10.6
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