Soaring Guidance
Issued by NWS Pueblo, CO
Issued by NWS Pueblo, CO
150
UXUS97 KPUB 171235
SRGPUB
Soaring Forecast
National Weather Service Pueblo, Colorado
0635 MDT Tuesday, September 17, 2024
This forecast is for Villa Grove, CO for Tuesday, September 17, 2024:
If the trigger temperature of 61.2 F/16.2 C is reached...then
Thermal Soaring Index....................... Good
Maximum rate of lift........................ 472 ft/min (2.4 m/s)
Maximum height of thermals.................. 15268 ft MSL (6293 ft AGL)
Forecast maximum temperature................... 67.0 F/19.9 C
Time of trigger temperature.................... 1130 MDT
Time of overdevelopment........................ 1400 MDT
Middle/high clouds during soaring window....... Overcast thin high
Surface winds during soaring window............ 20 mph or less
Height of the -3 thermal index................. 13006 ft MSL (4032 ft AGL)
Thermal soaring outlook for Wednesday 09/18.... Excellent
Wave Soaring Index............................. Not available
Remarks...
Sunrise/Sunset.................... 06:47:46 / 19:07:52 MDT
Total possible sunshine........... 12 hr 20 min 6 sec (740 min 6 sec)
Altitude of sun at 12:57:49 MDT... 53.57 degrees
Upper air data from numerical model forecast valid on 09/17/2024 at 0600 MDT
Freezing level.................. 15534 ft MSL (6559 ft AGL)
Convective condensation level... 15262 ft MSL (6287 ft AGL)
Lifted condensation level....... 15360 ft MSL (6385 ft AGL)
Lifted index.................... -3.5
K index......................... -7.3
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 -63.4 -82.1 245 67 35 1.0 0.5 M M M M M
45000 -60.6 -77.1 245 84 43 4.5 2.5 M M M M M
40000 -53.2 -63.8 245 74 38 7.1 3.9 M M M M M
38000 -48.9 -56.0 240 67 34 7.1 3.9 M M M M M
36000 -44.6 -48.3 235 61 31 7.1 3.9 M M M M M
34000 -40.1 -40.2 230 57 29 7.5 4.1 M M M M M
32000 -35.6 -32.1 225 53 28 7.5 4.1 M M M M M
30000 -31.7 -25.1 225 50 26 6.2 3.4 33.0 91.4 10.7 M M
29000 -29.8 -21.6 225 47 24 6.2 3.4 31.7 89.0 9.8 M M
28000 -27.5 -17.5 225 45 23 7.2 4.0 30.2 86.4 8.7 M M
27000 -25.0 -13.0 220 43 22 8.2 4.5 29.5 85.2 8.3 M M
26000 -22.6 -8.7 220 42 22 8.2 4.5 29.0 84.1 7.9 M M
25000 -20.1 -4.2 215 41 21 8.2 4.5 28.5 83.3 7.6 M M
24000 -17.6 0.3 215 40 21 8.6 4.7 28.0 82.4 7.3 M M
23000 -15.0 5.0 215 39 20 8.6 4.7 27.6 81.7 7.0 M M
22000 -12.4 9.7 210 38 20 8.7 4.8 27.3 81.1 6.8 M M
21000 -10.3 13.5 210 36 19 6.9 3.8 26.4 79.5 6.1 M M
20000 -8.2 17.2 210 35 18 6.9 3.8 25.4 77.7 5.3 M M
19500 -7.1 19.2 210 34 17 6.9 3.8 25.0 76.9 4.9 M M
19000 -6.1 21.0 210 33 17 6.1 3.4 24.5 76.1 4.5 M M
18500 -5.3 22.5 215 32 17 5.7 3.1 23.8 74.9 3.9 M M
18000 -4.5 23.9 215 32 16 5.8 3.2 23.2 73.7 3.3 M M
17500 -3.6 25.5 220 32 16 6.2 3.4 22.5 72.5 2.7 M M
17000 -2.8 27.0 220 32 17 6.2 3.4 21.9 71.5 2.1 M M
16500 -1.9 28.6 220 33 17 6.3 3.5 21.4 70.5 1.6 M M
16000 -1.0 30.2 220 34 18 6.4 3.5 20.8 69.5 1.0 M M
15500 -0.1 31.8 225 35 18 6.5 3.6 20.3 68.5 0.4 M M
15000 0.8 33.4 225 36 19 6.3 3.5 19.8 67.6 -0.2 559 2.8
14500 1.6 34.9 225 37 19 5.8 3.2 19.2 66.6 -0.8 518 2.6
14000 2.8 37.0 225 38 19 6.3 3.5 18.3 64.9 -1.8 461 2.3
13500 3.7 38.7 225 38 19 6.0 3.3 17.7 63.9 -2.4 420 2.1
13000 4.4 39.9 225 35 18 4.9 2.7 17.0 62.6 -3.2 384 2.0
12500 5.0 41.0 225 31 16 5.0 2.7 16.3 61.3 -4.0 350 1.8
12000 5.6 42.1 225 30 15 4.3 2.4 15.5 59.9 -4.9 318 1.6
11750 5.9 42.6 225 29 15 4.5 2.5 15.1 59.1 -5.4 303 1.5
11500 6.1 43.0 225 29 15 4.4 2.4 14.7 58.4 -5.9 287 1.5
11250 6.4 43.5 225 29 15 5.0 2.8 14.3 57.7 -6.3 272 1.4
11000 6.8 44.2 225 27 14 5.9 3.2 14.0 57.1 -6.7 254 1.3
10750 7.1 44.8 220 26 13 4.9 2.7 13.6 56.6 -7.1 235 1.2
10500 7.4 45.3 220 25 13 5.2 2.9 13.3 55.9 -7.5 219 1.1
10250 7.7 45.9 220 23 12 1.8 1.0 12.9 55.2 -8.0 203 1.0
10000 7.6 45.7 220 21 11 -1.8 -1.0 12.0 53.7 -8.8 198 1.0
9750 7.6 45.7 220 19 10 -0.5 -0.3 11.2 52.2 -9.6 193 1.0
9500 7.6 45.7 220 17 9 1.5 0.8 10.5 51.0 -10.4 185 0.9
9250 7.7 45.9 220 13 7 1.7 0.9 10.0 49.9 -11.0 173 0.9
9000 7.4 45.3 225 6 3 -16.2 -8.9 8.9 48.0 -12.0 175 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 * * * * * *
09/17/2024 at 0900 MDT | 09/17/2024 at 1200 MDT
|
CAPE... +11.5 LI... +1.0 | CAPE... +426.9 LI... -0.7
CINH... -142.8 K Index... -4.1 | CINH... -0.4 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 -62.4 -80.3 240 63 32 0.9 0.5 | -61.5 -78.7 240 57 29 0.8 0.4
45000 -60.0 -76.0 240 83 43 3.8 2.1 | -59.3 -74.7 240 87 45 3.7 2.0
40000 -53.7 -64.7 240 74 38 7.3 4.0 | -53.2 -63.8 240 89 46 6.2 3.4
38000 -49.4 -56.9 235 67 35 7.2 3.9 | -49.6 -57.3 235 80 41 6.0 3.3
36000 -45.1 -49.2 230 61 32 7.2 3.9 | -46.0 -50.8 230 72 37 6.1 3.3
34000 -40.5 -40.9 225 59 30 7.9 4.3 | -41.4 -42.5 225 69 35 8.3 4.5
32000 -35.8 -32.4 225 57 29 7.8 4.3 | -36.4 -33.5 220 67 34 8.3 4.5
30000 -31.7 -25.1 220 53 27 6.4 3.5 | -32.2 -26.0 215 62 32 6.4 3.5
29000 -29.4 -20.9 215 50 26 6.4 3.5 | -29.8 -21.6 215 59 30 6.4 3.5
28000 -27.5 -17.5 215 48 24 7.2 4.0 | -27.9 -18.2 210 56 29 7.2 3.9
27000 -25.0 -13.0 210 45 23 8.4 4.6 | -25.2 -13.4 205 53 27 9.1 5.0
26000 -22.5 -8.5 205 42 22 8.4 4.6 | -22.5 -8.5 200 50 26 9.1 5.0
25000 -20.0 -4.0 200 40 21 8.4 4.6 | -19.8 -3.6 195 47 24 9.1 5.0
24000 -17.4 0.7 200 40 21 8.4 4.6 | -17.3 0.9 195 46 24 8.1 4.4
23000 -14.9 5.2 200 42 22 8.4 4.6 | -14.9 5.2 195 47 24 8.1 4.4
22000 -12.4 9.7 195 44 22 8.7 4.8 | -12.5 9.5 195 47 24 8.3 4.6
21000 -10.3 13.5 200 42 22 6.2 3.4 | -10.6 12.9 200 46 24 6.0 3.3
20000 -8.5 16.7 205 40 21 6.3 3.4 | -8.9 16.0 210 46 24 6.2 3.4
19500 -7.5 18.5 210 39 20 6.2 3.4 | -8.0 17.6 215 46 24 6.4 3.5
19000 -6.6 20.1 210 38 20 5.7 3.1 | -7.2 19.0 215 46 24 6.6 3.6
18500 -5.8 21.6 215 38 20 5.3 2.9 | -6.3 20.7 220 46 24 6.5 3.6
18000 -5.1 22.8 215 39 20 5.3 2.9 | -5.4 22.3 220 46 24 6.7 3.7
17500 -4.2 24.4 220 39 20 6.6 3.6 | -4.5 23.9 220 46 24 5.5 3.0
17000 -3.3 26.1 220 38 20 6.7 3.7 | -3.7 25.3 220 46 24 5.6 3.1
16500 -2.5 27.5 220 38 20 6.2 3.4 | -2.9 26.8 220 46 24 5.7 3.1
16000 -1.7 28.9 220 40 20 5.7 3.1 | -2.1 28.2 220 46 24 6.0 3.3
15500 -1.0 30.2 225 41 21 5.8 3.2 | -1.3 29.7 220 46 24 6.0 3.3
15000 0.2 32.4 225 41 21 6.1 3.3 | -0.1 31.8 220 44 23 5.5 3.0
14500 1.0 33.8 225 41 21 5.0 2.7 | 0.7 33.3 220 43 22 3.9 2.1
14000 1.7 35.1 225 39 20 5.9 3.2 | 1.3 34.3 220 41 21 5.3 2.9
13500 2.5 36.5 225 37 19 5.9 3.2 | 2.1 35.8 220 39 20 5.5 3.0
13000 3.4 38.1 225 34 17 6.5 3.6 | 2.9 37.2 220 35 18 5.7 3.1
12500 4.3 39.7 220 31 16 6.6 3.6 | 3.7 38.7 220 30 15 5.6 3.1
12000 5.0 41.0 220 29 15 5.1 2.8 | 4.6 40.3 215 27 14 6.4 3.5
11750 5.4 41.7 220 29 15 6.4 3.5 | 5.0 41.0 215 26 13 6.5 3.5
11500 5.9 42.6 220 29 15 6.4 3.5 | 5.5 41.9 210 25 13 6.3 3.5
11250 6.3 43.3 220 29 15 5.7 3.1 | 5.9 42.6 210 25 13 6.9 3.8
11000 6.6 43.9 220 27 14 5.0 2.8 | 6.4 43.5 210 23 12 7.7 4.2
10750 7.0 44.6 220 26 13 4.8 2.6 | 7.0 44.6 205 21 11 7.2 4.0
10500 7.3 45.1 220 24 12 5.5 3.0 | 7.4 45.3 205 19 10 6.8 3.7
10250 7.7 45.9 215 22 11 1.8 1.0 | 7.9 46.2 200 18 9 7.2 3.9
10000 7.6 45.7 215 20 10 -2.1 -1.1 | 8.4 47.1 200 16 8 7.3 4.0
9750 7.5 45.5 215 18 9 -0.9 -0.5 | 8.9 48.0 200 15 8 8.0 4.4
9500 7.4 45.3 215 15 8 0.7 0.4 | 9.4 48.9 200 14 7 7.9 4.3
9250 7.6 45.7 215 13 7 8.8 4.8 | 10.1 50.2 200 12 6 14.4 7.9
9000 8.9 48.0 215 8 4 28.9 15.9 | 12.4 54.3 200 10 5 61.0 33.4
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
09/17/2024 at 1500 MDT | 09/17/2024 at 1800 MDT
|
CAPE... +585.9 LI... -1.4 | CAPE... +153.0 LI... -0.7
CINH... -0.1 K Index... +23.8 | CINH... -11.2 K Index... +1.5
|
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 -61.3 -78.3 240 53 27 0.6 0.3 | -60.3 -76.5 240 49 25 3.2 1.7
45000 -59.4 -74.9 240 84 43 4.0 2.2 | -55.5 -67.9 245 74 38 3.3 1.8
40000 -52.9 -63.2 235 81 42 5.8 3.2 | -50.2 -58.4 235 85 44 4.6 2.5
38000 -49.5 -57.1 230 72 37 5.7 3.1 | -47.5 -53.5 235 83 43 4.6 2.5
36000 -46.1 -51.0 220 64 33 5.7 3.1 | -44.7 -48.5 230 80 41 4.6 2.5
34000 -41.5 -42.7 215 62 32 8.6 4.7 | -41.3 -42.3 230 78 40 6.3 3.4
32000 -36.3 -33.3 215 61 32 8.7 4.7 | -37.5 -35.5 225 77 39 6.3 3.4
30000 -31.1 -24.0 210 59 30 7.4 4.0 | -33.5 -28.3 220 73 38 7.1 3.9
29000 -28.9 -20.0 210 57 29 7.4 4.1 | -31.4 -24.5 215 71 37 7.1 3.9
28000 -26.7 -16.1 210 55 28 7.6 4.2 | -28.7 -19.7 215 68 35 7.1 3.9
27000 -24.2 -11.6 210 53 27 8.7 4.7 | -26.7 -16.1 215 66 34 6.7 3.7
26000 -21.6 -6.9 210 50 26 8.7 4.8 | -24.7 -12.5 215 65 33 6.7 3.7
25000 -19.1 -2.4 210 47 24 8.9 4.9 | -22.7 -8.9 215 63 33 6.7 3.7
24000 -16.9 1.6 210 46 23 6.5 3.6 | -20.6 -5.1 215 62 32 7.2 4.0
23000 -15.0 5.0 215 45 23 6.5 3.6 | -18.5 -1.3 220 62 32 7.3 4.0
22000 -13.1 8.4 215 45 23 6.6 3.6 | -16.3 2.7 220 62 32 7.3 4.0
21000 -11.3 11.7 220 45 23 6.1 3.4 | -14.1 6.6 225 61 32 7.3 4.0
20000 -9.5 14.9 220 45 23 6.2 3.4 | -12.0 10.4 225 61 31 7.3 4.0
19500 -8.6 16.5 220 45 23 6.2 3.4 | -10.9 12.4 225 61 31 7.4 4.0
19000 -7.8 18.0 220 45 23 6.1 3.3 | -9.8 14.4 230 61 31 7.5 4.1
18500 -6.9 19.6 220 44 23 5.8 3.2 | -8.7 16.3 230 60 31 7.7 4.2
18000 -6.1 21.0 225 44 23 5.8 3.2 | -7.6 18.3 230 60 31 7.8 4.3
17500 -5.2 22.6 225 44 22 5.6 3.1 | -6.5 20.3 230 60 31 7.5 4.1
17000 -4.5 23.9 225 43 22 5.6 3.1 | -5.4 22.3 230 59 30 7.4 4.0
16500 -3.7 25.3 225 43 22 5.5 3.0 | -4.2 24.4 235 59 30 7.1 3.9
16000 -2.9 26.8 225 42 21 5.3 2.9 | -3.3 26.1 235 58 30 6.2 3.4
15500 -1.7 28.9 230 40 21 5.0 2.8 | -2.4 27.7 235 56 29 6.2 3.4
15000 -1.1 30.0 230 39 20 4.7 2.6 | -1.5 29.3 235 55 28 6.6 3.6
14500 -0.4 31.3 230 38 20 5.0 2.7 | -0.6 30.9 240 54 28 6.5 3.6
14000 0.3 32.5 230 38 19 4.3 2.4 | 0.7 33.3 240 50 26 6.6 3.6
13500 0.9 33.6 235 37 19 4.6 2.5 | 1.6 34.9 240 46 24 7.8 4.3
13000 1.9 35.4 235 35 18 8.1 4.4 | 2.6 36.7 240 44 22 6.5 3.6
12500 3.0 37.4 235 33 17 7.5 4.1 | 3.5 38.3 240 41 21 7.2 3.9
12000 4.0 39.2 230 32 17 6.3 3.4 | 4.4 39.9 235 39 20 6.9 3.8
11750 4.4 39.9 230 32 16 6.5 3.6 | 5.0 41.0 235 37 19 8.8 4.8
11500 4.9 40.8 230 31 16 6.5 3.6 | 5.6 42.1 235 36 19 8.3 4.6
11250 5.3 41.5 230 30 15 6.7 3.6 | 6.1 43.0 235 35 18 8.7 4.8
11000 5.8 42.4 230 29 15 6.8 3.8 | 6.8 44.2 230 35 18 8.8 4.8
10750 6.3 43.3 230 28 14 7.2 3.9 | 7.4 45.3 230 34 17 9.6 5.3
10500 6.7 44.1 230 26 13 7.2 3.9 | 8.2 46.8 230 33 17 10.4 5.7
10250 7.2 45.0 230 24 12 7.9 4.3 | 8.9 48.0 230 32 17 10.0 5.5
10000 7.8 46.0 230 22 11 9.1 5.0 | 9.6 49.3 230 31 16 9.5 5.2
9750 8.4 47.1 230 19 10 9.4 5.1 | 10.3 50.5 225 30 15 9.6 5.3
9500 9.1 48.4 230 17 9 9.1 5.0 | 11.1 52.0 225 28 15 10.4 5.7
9250 9.7 49.5 235 14 7 10.1 5.5 | 11.8 53.2 225 26 13 11.3 6.2
9000 10.6 51.1 235 9 4 18.8 10.3 | 12.6 54.7 225 17 9 10.1 5.5
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
________________________________________________________________________________
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