Soaring Guidance
Issued by NWS Pueblo, CO
Issued by NWS Pueblo, CO
180
UXUS97 KPUB 211217
SRGPUB
Soaring Forecast
National Weather Service Pueblo, Colorado
0617 MDT Saturday, September 21, 2024
This forecast is for Villa Grove, CO for Saturday, September 21, 2024:
If the trigger temperature of 62.7 F/17.1 C is reached...then
Thermal Soaring Index....................... Fair
Maximum rate of lift........................ 307 ft/min (1.6 m/s)
Maximum height of thermals.................. 15815 ft MSL (6831 ft AGL)
Forecast maximum temperature................... 64.0 F/18.2 C
Time of trigger temperature.................... 0930 MDT
Time of overdevelopment........................ 1200 MDT
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................. 10417 ft MSL (1433 ft AGL)
Thermal soaring outlook for Sunday 09/22....... Poor
Wave Soaring Index............................. Not available
Remarks...
Sunrise/Sunset.................... 06:51:15 / 19:01:32 MDT
Total possible sunshine........... 12 hr 10 min 17 sec (730 min 17 sec)
Altitude of sun at 12:56:23 MDT... 52.01 degrees
Upper air data from numerical model forecast valid on 09/21/2024 at 0600 MDT
Freezing level.................. 14871 ft MSL (5887 ft AGL)
Convective condensation level... 16604 ft MSL (7620 ft AGL)
Lifted condensation level....... 16461 ft MSL (7477 ft AGL)
Lifted index.................... -0.4
K index......................... -8.9
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 -82.7 235 56 29 2.6 1.4 M M M M M
45000 -58.6 -73.5 220 77 39 5.7 3.1 M M M M M
40000 -49.8 -57.6 220 90 46 5.1 2.8 M M M M M
38000 -46.7 -52.1 220 91 47 5.1 2.8 M M M M M
36000 -43.6 -46.5 220 91 47 5.2 2.8 M M M M M
34000 -39.9 -39.8 215 86 45 6.7 3.7 M M M M M
32000 -35.9 -32.6 215 79 41 6.7 3.7 M M M M M
30000 -32.3 -26.1 215 68 35 5.5 3.0 32.6 90.6 11.7 M M
29000 -30.3 -22.5 215 59 30 5.5 3.0 30.6 87.0 10.2 M M
28000 -28.7 -19.7 215 52 27 5.7 3.2 29.1 84.4 9.2 M M
27000 -26.7 -16.1 210 47 24 6.7 3.7 27.9 82.1 8.3 M M
26000 -24.7 -12.5 210 42 22 6.7 3.7 26.7 80.1 7.4 M M
25000 -22.7 -8.9 210 37 19 6.6 3.6 25.7 78.3 6.6 M M
24000 -20.4 -4.7 210 34 17 8.0 4.4 24.9 76.8 6.0 M M
23000 -18.0 -0.4 210 31 16 8.0 4.4 24.2 75.6 5.5 M M
22000 -15.6 3.9 210 28 14 8.0 4.4 23.7 74.7 5.1 M M
21000 -13.3 8.1 205 25 13 7.9 4.3 23.0 73.5 4.6 M M
20000 -10.9 12.4 205 24 12 7.9 4.3 22.4 72.3 4.1 M M
19500 -9.7 14.5 205 23 12 7.8 4.3 22.1 71.8 3.9 M M
19000 -8.6 16.5 205 22 11 6.0 3.3 21.8 71.2 3.6 M M
18500 -7.9 17.8 205 22 11 5.0 2.7 20.9 69.7 2.8 M M
18000 -7.2 19.0 205 22 11 4.9 2.7 20.2 68.3 2.1 M M
17500 -6.4 20.5 205 22 11 6.7 3.7 19.5 67.1 1.5 M M
17000 -5.5 22.1 205 22 11 6.7 3.7 19.0 66.2 0.9 M M
16500 -4.5 23.9 205 22 11 7.9 4.3 18.5 65.4 0.4 M M
16000 -3.3 26.1 205 22 11 8.5 4.7 18.3 65.0 0.2 M M
15500 -2.1 28.2 205 22 11 8.9 4.9 18.1 64.7 -0.1 686 3.5
15000 -0.0 32.0 205 21 11 10.1 5.6 18.1 64.6 -0.2 601 3.1
14500 1.3 34.3 205 20 10 8.5 4.7 18.0 64.4 -0.4 548 2.8
14000 2.7 36.9 205 19 10 9.5 5.2 18.0 64.3 -0.4 491 2.5
13500 4.1 39.4 205 17 9 8.4 4.6 17.9 64.3 -0.4 433 2.2
13000 5.3 41.5 205 16 8 9.4 5.2 17.7 63.9 -0.7 382 1.9
12500 6.7 44.1 200 14 7 9.1 5.0 17.6 63.7 -0.8 327 1.7
12000 7.8 46.0 200 13 6 7.3 4.0 17.3 63.2 -1.2 279 1.4
11750 8.3 46.9 200 12 6 8.0 4.4 17.2 62.9 -1.4 255 1.3
11500 8.9 48.0 200 11 6 8.0 4.4 17.0 62.7 -1.6 232 1.2
11250 9.4 48.9 195 11 6 6.7 3.7 16.9 62.4 -1.8 209 1.1
11000 9.8 49.6 195 10 5 5.8 3.2 16.6 61.9 -2.1 190 1.0
10750 10.2 50.4 195 10 5 5.0 2.8 16.3 61.3 -2.5 171 0.9
10500 10.4 50.7 195 10 5 4.5 2.5 15.9 60.6 -2.9 155 0.8
10250 10.7 51.3 195 9 5 1.5 0.8 15.4 59.8 -3.4 140 0.7
10000 10.6 51.1 200 9 5 -1.6 -0.9 14.6 58.3 -4.2 136 0.7
9750 10.5 50.9 200 9 4 -0.3 -0.2 13.8 56.9 -5.1 131 0.7
9500 10.4 50.7 200 8 4 -1.3 -0.7 13.1 55.5 -5.9 126 0.6
9250 9.9 49.8 205 7 4 -14.1 -7.8 11.9 53.4 -7.1 133 0.7
9000 7.5 45.5 245 3 2 -62.8 -34.5 8.6 47.5 -10.3 199 1.0
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 * * * * * *
09/21/2024 at 0900 MDT | 09/21/2024 at 1200 MDT
|
CAPE... +336.1 LI... -2.2 | CAPE... +27.9 LI... +0.1
CINH... -84.0 K Index... +16.2 | CINH... -1.4 K Index... +23.0
|
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 -61.8 -79.2 230 50 26 2.1 1.1 | -59.8 -75.6 225 42 22 3.0 1.6
45000 -57.8 -72.0 220 80 41 4.8 2.6 | -55.2 -67.4 215 80 41 2.6 1.4
40000 -50.2 -58.4 215 96 50 4.9 2.7 | -51.3 -60.3 210 108 56 2.7 1.5
38000 -47.3 -53.1 215 95 49 4.9 2.7 | -49.7 -57.5 210 97 50 2.7 1.5
36000 -44.3 -47.7 215 95 49 4.9 2.7 | -48.1 -54.6 210 87 45 2.7 1.5
34000 -41.1 -42.0 210 88 45 5.6 3.1 | -44.1 -47.4 205 76 39 8.8 4.8
32000 -37.7 -35.9 210 80 41 5.6 3.1 | -38.8 -37.8 200 65 33 8.8 4.8
30000 -34.3 -29.7 210 68 35 5.8 3.2 | -32.9 -27.2 195 57 30 8.7 4.8
29000 -32.5 -26.5 210 60 31 5.8 3.2 | -30.3 -22.5 190 55 28 8.7 4.8
28000 -30.8 -23.4 205 53 27 5.7 3.1 | -27.7 -17.9 190 53 27 8.6 4.7
27000 -28.0 -18.4 205 48 25 8.1 4.4 | -25.4 -13.7 190 49 25 7.6 4.2
26000 -25.6 -14.1 205 45 23 8.1 4.4 | -23.2 -9.8 185 45 23 7.6 4.2
25000 -23.2 -9.8 200 43 22 8.1 4.4 | -20.9 -5.6 185 41 21 7.7 4.2
24000 -20.7 -5.3 200 39 20 8.1 4.4 | -18.7 -1.7 185 36 19 7.2 3.9
23000 -18.3 -0.9 195 36 18 8.1 4.4 | -16.6 2.1 180 31 16 7.2 3.9
22000 -15.9 3.4 195 32 17 8.4 4.6 | -14.5 5.9 180 26 14 7.3 4.0
21000 -14.0 6.8 195 31 16 5.8 3.2 | -12.6 9.3 170 23 12 6.3 3.5
20000 -12.3 9.9 200 30 15 6.0 3.3 | -10.7 12.7 165 20 10 6.4 3.5
19500 -11.4 11.5 200 29 15 6.1 3.3 | -9.8 14.4 160 19 10 6.4 3.5
19000 -10.5 13.1 200 29 15 6.0 3.3 | -8.9 16.0 155 18 9 6.2 3.4
18500 -9.7 14.5 205 29 15 6.0 3.3 | -8.1 17.4 150 18 9 5.8 3.2
18000 -8.9 16.0 205 30 15 6.3 3.4 | -7.2 19.0 145 17 9 5.9 3.2
17500 -7.8 18.0 205 28 14 9.1 5.0 | -6.4 20.5 140 17 9 5.8 3.2
17000 -6.6 20.1 200 26 13 9.0 4.9 | -5.6 21.9 135 17 9 5.8 3.2
16500 -5.3 22.5 195 23 12 9.2 5.0 | -4.7 23.5 125 17 9 5.8 3.2
16000 -4.0 24.8 195 21 11 9.2 5.0 | -3.9 25.0 120 17 9 5.8 3.2
15500 -2.7 27.1 190 19 10 9.1 5.0 | -3.1 26.4 120 18 9 5.8 3.2
15000 -1.4 29.5 185 17 9 8.8 4.8 | -2.4 27.7 115 19 10 3.8 2.1
14500 -0.0 32.0 180 16 8 8.9 4.9 | -1.5 29.3 110 20 11 2.8 1.5
14000 1.3 34.3 175 16 8 9.5 5.2 | -1.1 30.0 110 22 11 4.0 2.2
13500 2.7 36.9 170 16 8 10.0 5.5 | -0.6 30.9 110 24 12 3.7 2.0
13000 4.7 40.5 165 15 8 10.6 5.8 | -0.0 32.0 115 25 13 4.0 2.2
12500 6.2 43.2 155 15 8 9.6 5.3 | 0.6 33.1 115 26 13 4.0 2.2
12000 7.4 45.3 150 14 7 8.1 4.4 | 1.4 34.5 115 26 13 6.5 3.5
11750 8.1 46.6 145 14 7 10.3 5.7 | 1.8 35.2 115 26 13 6.1 3.3
11500 8.8 47.8 145 14 7 9.4 5.1 | 2.3 36.1 115 26 13 6.1 3.3
11250 9.4 48.9 140 14 7 6.7 3.7 | 2.7 36.9 115 25 13 6.7 3.7
11000 9.8 49.6 140 13 7 4.9 2.7 | 3.2 37.8 120 24 12 7.2 4.0
10750 10.2 50.4 140 13 6 6.3 3.4 | 3.8 38.8 120 23 12 7.5 4.1
10500 10.6 51.1 135 12 6 6.7 3.7 | 4.3 39.7 120 22 12 8.0 4.4
10250 10.9 51.6 135 11 6 3.2 1.8 | 4.9 40.8 120 22 11 8.2 4.5
10000 11.0 51.8 135 10 5 1.5 0.8 | 5.5 41.9 125 21 11 8.5 4.7
9750 11.0 51.8 135 8 4 1.5 0.8 | 6.1 43.0 125 20 10 8.4 4.6
9500 11.0 51.8 140 6 3 2.4 1.3 | 6.7 44.1 125 18 9 9.5 5.2
9250 11.4 52.5 135 3 2 8.8 4.8 | 7.5 45.5 125 16 8 12.0 6.6
9000 12.3 54.1 000 0 0 14.7 8.1 | 8.4 47.1 125 12 6 13.2 7.2
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
09/21/2024 at 1500 MDT | 09/21/2024 at 1800 MDT
|
CAPE... +10.5 LI... -0.5 | CAPE... +19.1 LI... -0.6
CINH... 0.0 K Index... +26.2 | CINH... 0.0 K Index... +25.3
|
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 -60.7 -77.3 215 38 20 2.8 1.5 | -59.1 -74.4 210 31 16 3.8 2.1
45000 -56.4 -69.5 215 71 37 3.1 1.7 | -53.7 -64.7 215 49 25 2.7 1.5
40000 -51.4 -60.5 205 87 45 3.9 2.2 | -49.4 -56.9 205 60 31 1.7 0.9
38000 -49.0 -56.2 200 84 43 4.0 2.2 | -49.0 -56.2 205 56 29 0.7 0.4
36000 -46.6 -51.9 200 80 41 4.0 2.2 | -48.6 -55.5 200 51 26 0.7 0.4
34000 -43.1 -45.6 195 78 40 6.8 3.8 | -45.7 -50.3 200 42 22 7.8 4.3
32000 -39.0 -38.2 190 77 40 6.8 3.8 | -41.1 -42.0 205 30 15 7.8 4.3
30000 -34.8 -30.6 190 71 36 7.3 4.0 | -35.4 -31.7 210 25 13 8.8 4.8
29000 -32.6 -26.7 185 66 34 7.3 4.0 | -32.8 -27.0 215 25 13 8.8 4.8
28000 -29.9 -21.8 180 60 31 7.2 4.0 | -30.2 -22.4 215 25 13 8.9 4.9
27000 -27.5 -17.5 180 57 29 8.0 4.4 | -27.8 -18.0 215 25 13 8.1 4.5
26000 -25.1 -13.2 180 55 29 8.1 4.4 | -25.3 -13.5 210 25 13 8.1 4.5
25000 -22.7 -8.9 180 54 28 8.1 4.4 | -22.9 -9.2 210 24 12 8.1 4.5
24000 -20.4 -4.7 180 50 26 7.9 4.3 | -20.6 -5.1 210 24 12 7.4 4.1
23000 -18.1 -0.6 180 45 23 8.0 4.4 | -18.5 -1.3 205 24 13 7.4 4.1
22000 -15.8 3.6 180 40 21 8.3 4.5 | -16.3 2.7 200 25 13 7.4 4.1
21000 -13.7 7.3 185 36 19 6.8 3.7 | -14.2 6.4 200 25 13 7.0 3.8
20000 -11.7 10.9 190 34 18 6.8 3.7 | -12.2 10.0 195 25 13 7.0 3.8
19500 -10.7 12.7 190 33 17 6.8 3.7 | -11.2 11.8 195 25 13 7.0 3.8
19000 -9.7 14.5 195 32 17 6.8 3.7 | -10.2 13.6 190 25 13 7.0 3.8
18500 -8.8 16.2 195 31 16 6.7 3.7 | -9.2 15.4 190 25 13 6.3 3.4
18000 -7.8 18.0 195 29 15 6.8 3.7 | -8.3 17.1 185 26 13 6.3 3.5
17500 -6.9 19.6 195 28 14 6.0 3.3 | -7.4 18.7 185 26 13 6.2 3.4
17000 -6.0 21.2 195 27 14 6.0 3.3 | -6.5 20.3 180 25 13 6.1 3.4
16500 -5.1 22.8 195 26 13 5.9 3.3 | -5.6 21.9 175 25 13 6.2 3.4
16000 -4.3 24.3 195 24 13 5.8 3.2 | -4.8 23.4 165 25 13 6.2 3.4
15500 -3.4 25.9 195 23 12 5.7 3.1 | -3.4 25.9 155 25 13 6.3 3.5
15000 -2.5 27.5 195 21 11 7.5 4.1 | -2.5 27.5 150 24 12 6.4 3.5
14500 -0.9 30.4 190 17 9 6.5 3.6 | -1.6 29.1 145 24 12 4.7 2.6
14000 -0.1 31.8 180 15 8 6.5 3.6 | -1.1 30.0 140 23 12 4.4 2.4
13500 0.8 33.4 165 13 7 6.2 3.4 | -0.5 31.1 130 22 12 4.3 2.4
13000 1.6 34.9 150 14 7 4.9 2.7 | 0.0 32.0 120 21 11 2.1 1.1
12500 2.3 36.1 130 15 8 6.0 3.3 | 0.3 32.5 110 20 10 2.1 1.2
12000 2.7 36.9 120 17 9 -0.7 -0.4 | 0.5 32.9 100 20 10 0.9 0.5
11750 2.7 36.9 110 17 9 0.4 0.2 | 0.6 33.1 095 19 10 1.2 0.7
11500 2.7 36.9 105 18 9 0.3 0.2 | 0.7 33.3 095 19 10 1.0 0.6
11250 2.7 36.9 100 18 9 -0.0 -0.0 | 0.8 33.4 090 19 10 2.0 1.1
11000 2.7 36.9 095 18 9 -0.8 -0.5 | 1.0 33.8 085 18 9 3.4 1.9
10750 2.7 36.9 085 18 9 0.3 0.2 | 1.3 34.3 080 18 9 4.7 2.6
10500 2.7 36.9 075 17 9 0.1 0.1 | 1.7 35.1 075 17 9 5.3 2.9
10250 2.8 37.0 065 17 9 4.2 2.3 | 2.1 35.8 075 16 8 6.4 3.5
10000 3.3 37.9 060 16 8 8.7 4.8 | 2.6 36.7 075 15 8 8.2 4.5
9750 3.9 39.0 055 15 8 7.9 4.3 | 3.2 37.8 070 13 7 8.4 4.6
9500 4.5 40.1 050 15 7 9.9 5.4 | 3.8 38.8 070 11 6 8.0 4.4
9250 5.4 41.7 045 13 7 16.8 9.2 | 4.3 39.7 070 9 5 9.6 5.2
9000 7.3 45.1 040 11 6 37.7 20.7 | 5.4 41.7 060 5 3 23.0 12.6
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