Soaring Guidance
Issued by NWS Pueblo, CO
Issued by NWS Pueblo, CO
623
UXUS97 KPUB 301222
SRGPUB
Soaring Forecast
National Weather Service Pueblo, Colorado
0622 MDT Tuesday, April 30, 2024
This forecast is for Villa Grove, CO for Tuesday, April 30, 2024:
If the trigger temperature of 46.5 F/8.1 C is reached...then
Thermal Soaring Index....................... Excellent
Maximum rate of lift........................ 817 ft/min (4.2 m/s)
Maximum height of thermals.................. 20635 ft MSL (11663 ft AGL)
Forecast maximum temperature................... 65.0 F/18.8 C
Time of trigger temperature.................... 0830 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................. 17215 ft MSL (8244 ft AGL)
Thermal soaring outlook for Wednesday 05/01.... Excellent
Wave Soaring Index............................. Not available
Remarks...
Sunrise/Sunset.................... 06:07:02 / 19:54:22 MDT
Total possible sunshine........... 13 hr 47 min 20 sec (827 min 20 sec)
Altitude of sun at 13:00:42 MDT... 66.83 degrees
Upper air data from numerical model forecast valid on 04/30/2024 at 0600 MDT
Freezing level.................. 11582 ft MSL (2610 ft AGL)
Convective condensation level... 18139 ft MSL (9167 ft AGL)
Lifted condensation level....... 19177 ft MSL (10205 ft AGL)
Lifted index.................... -2.8
K index......................... -7.6
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 -59.4 -74.9 255 43 22 2.4 1.3 M M M M M
45000 -56.0 -68.8 255 46 24 -0.1 -0.1 M M M M M
40000 -55.8 -68.4 255 69 36 0.2 0.1 M M M M M
38000 -54.3 -65.7 260 69 36 3.6 2.0 M M M M M
36000 -52.1 -61.8 265 67 34 3.6 2.0 M M M M M
34000 -49.4 -56.9 265 65 33 6.3 3.5 M M M M M
32000 -45.6 -50.1 265 64 33 6.4 3.5 M M M M M
30000 -41.4 -42.5 265 64 33 8.4 4.6 22.8 73.1 3.5 M M
29000 -38.9 -38.0 265 64 33 8.5 4.7 22.3 72.1 3.1 M M
28000 -35.7 -32.3 265 64 33 8.5 4.7 21.8 71.2 2.8 M M
27000 -33.1 -27.6 265 63 32 9.0 4.9 21.4 70.5 2.5 M M
26000 -30.5 -22.9 265 61 32 8.9 4.9 21.0 69.8 2.2 M M
25000 -27.8 -18.0 265 60 31 8.9 4.9 20.7 69.3 2.0 M M
24000 -25.2 -13.4 265 58 30 8.2 4.5 20.5 68.9 1.8 M M
23000 -22.8 -9.0 265 53 27 8.1 4.4 19.8 67.6 1.3 M M
22000 -20.3 -4.5 260 49 25 8.1 4.4 19.2 66.6 0.8 M M
21000 -18.0 -0.4 255 44 23 7.4 4.1 18.7 65.6 0.3 M M
20000 -15.7 3.7 250 39 20 7.5 4.1 17.8 64.1 -0.4 957 4.9
19500 -14.6 5.7 245 36 19 7.5 4.1 17.5 63.5 -0.8 909 4.6
19000 -13.5 7.7 240 34 18 7.5 4.1 17.1 62.8 -1.1 861 4.4
18500 -12.4 9.7 235 33 17 6.7 3.7 16.8 62.2 -1.4 813 4.1
18000 -11.4 11.5 240 32 17 6.4 3.5 16.2 61.2 -2.0 770 3.9
17500 -10.5 13.1 240 32 16 6.2 3.4 15.7 60.2 -2.5 726 3.7
17000 -9.8 14.4 245 32 17 3.7 2.0 14.8 58.7 -3.3 691 3.5
16500 -9.2 15.4 250 34 17 3.9 2.2 13.9 57.0 -4.2 659 3.3
16000 -8.7 16.3 255 35 18 3.4 1.8 12.9 55.2 -5.1 628 3.2
15500 -8.2 17.2 260 38 20 3.4 1.9 11.8 53.3 -6.2 600 3.0
15000 -7.8 18.0 265 41 21 4.8 2.6 10.8 51.5 -7.2 572 2.9
14500 -6.9 19.6 265 44 22 6.7 3.7 10.3 50.5 -7.9 532 2.7
14000 -5.9 21.4 270 48 25 7.2 4.0 9.1 48.4 -9.1 480 2.4
13500 -4.8 23.4 270 49 25 8.1 4.5 8.8 47.9 -9.5 431 2.2
13000 -3.7 25.3 270 50 26 8.5 4.6 8.5 47.3 -9.9 382 1.9
12500 -2.3 27.9 270 49 25 9.5 5.2 8.5 47.3 -10.0 325 1.7
12000 -0.9 30.4 270 48 25 8.5 4.7 8.4 47.1 -10.1 269 1.4
11750 -0.3 31.5 270 48 24 9.1 5.0 8.3 47.0 -10.3 243 1.2
11500 0.5 32.9 270 47 24 9.9 5.4 8.3 47.0 -10.3 214 1.1
11250 1.2 34.2 270 47 24 10.1 5.6 8.3 47.0 -10.3 184 0.9
11000 1.9 35.4 270 46 24 7.7 4.2 8.3 47.0 -10.4 156 0.8
10750 2.3 36.1 270 45 23 5.5 3.0 8.0 46.4 -10.7 135 0.7
10500 2.8 37.0 270 42 22 6.0 3.3 7.7 45.9 -11.0 115 0.6
10250 3.2 37.8 265 40 20 6.3 3.5 7.4 45.4 -11.3 95 0.5
10000 3.5 38.3 265 37 19 1.2 0.7 7.1 44.7 -11.7 77 0.4
9750 3.4 38.1 260 33 17 -3.8 -2.1 6.2 43.1 -12.7 75 0.4
9500 3.1 37.6 260 29 15 -3.3 -1.8 5.2 41.3 -13.7 76 0.4
9250 2.6 36.7 255 23 12 -11.5 -6.3 4.0 39.2 -15.0 83 0.4
9000 0.9 33.6 245 12 6 -38.9 -21.3 1.5 34.7 -17.5 128 0.6
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 * * * * * *
04/30/2024 at 0900 MDT | 04/30/2024 at 1200 MDT
|
CAPE... 0.0 LI... +0.9 | CAPE... 0.0 LI... +1.5
CINH... 0.0 K Index... -25.4 | CINH... 0.0 K Index... -29.1
|
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 -58.2 -72.8 250 43 22 1.6 0.9 | -58.5 -73.3 255 42 22 1.3 0.7
45000 -55.9 -68.6 255 51 26 -0.7 -0.4 | -56.7 -70.1 260 60 31 -1.6 -0.9
40000 -56.7 -70.1 260 69 36 -0.4 -0.2 | -58.8 -73.8 260 70 36 -1.2 -0.7
38000 -55.2 -67.4 260 69 35 3.7 2.0 | -57.0 -70.6 260 64 33 4.7 2.6
36000 -53.0 -63.4 260 65 33 3.7 2.0 | -54.2 -65.6 260 55 28 4.7 2.6
34000 -50.1 -58.2 260 61 32 7.1 3.9 | -50.6 -59.1 265 49 25 8.5 4.7
32000 -45.8 -50.4 265 60 31 7.1 3.9 | -45.5 -49.9 265 50 26 8.5 4.7
30000 -41.4 -42.5 265 59 30 8.2 4.5 | -40.5 -40.9 265 51 26 8.1 4.5
29000 -39.0 -38.2 265 58 30 8.2 4.5 | -38.1 -36.6 265 51 26 8.1 4.5
28000 -35.9 -32.6 265 58 30 8.2 4.5 | -35.0 -31.0 265 51 26 8.1 4.5
27000 -33.4 -28.1 265 57 30 8.4 4.6 | -32.6 -26.7 265 51 26 8.2 4.5
26000 -30.9 -23.6 265 57 29 8.4 4.6 | -30.1 -22.2 265 49 25 8.2 4.5
25000 -28.4 -19.1 265 56 29 8.4 4.6 | -27.7 -17.9 265 48 25 8.2 4.5
24000 -25.9 -14.6 265 54 28 7.7 4.2 | -25.3 -13.5 260 47 24 7.6 4.1
23000 -23.6 -10.5 260 50 26 7.7 4.2 | -23.0 -9.4 260 46 24 7.6 4.2
22000 -21.3 -6.3 260 46 24 7.7 4.2 | -20.7 -5.3 260 45 23 7.6 4.2
21000 -19.0 -2.2 260 42 22 8.8 4.8 | -18.5 -1.3 265 45 23 7.2 3.9
20000 -16.4 2.5 255 38 19 8.7 4.8 | -16.3 2.7 265 44 23 7.2 4.0
19500 -15.1 4.8 255 36 18 8.7 4.8 | -15.3 4.5 270 44 23 7.2 4.0
19000 -13.8 7.2 255 34 17 8.7 4.8 | -14.2 6.4 270 44 23 7.2 3.9
18500 -12.4 9.7 255 32 16 8.9 4.9 | -13.1 8.4 270 43 22 7.4 4.1
18000 -11.1 12.0 255 31 16 9.0 4.9 | -12.0 10.4 275 41 21 7.4 4.1
17500 -9.8 14.4 255 30 15 8.8 4.8 | -10.9 12.4 275 39 20 7.5 4.1
17000 -8.5 16.7 260 31 16 8.0 4.4 | -9.7 14.5 275 39 20 7.7 4.2
16500 -7.3 18.9 260 32 17 8.2 4.5 | -8.6 16.5 280 40 20 7.7 4.3
16000 -6.2 20.8 265 34 18 6.4 3.5 | -7.4 18.7 280 41 21 7.1 3.9
15500 -5.2 22.6 265 37 19 6.3 3.5 | -6.4 20.5 280 42 22 7.2 4.0
15000 -4.1 24.6 270 41 21 2.7 1.5 | -5.3 22.5 280 43 22 6.7 3.7
14500 -3.6 25.5 275 45 23 2.1 1.1 | -3.9 25.0 280 44 23 4.5 2.5
14000 -3.5 25.7 275 47 24 1.5 0.8 | -3.4 25.9 280 44 22 4.2 2.3
13500 -3.3 26.1 275 48 25 1.9 1.0 | -2.8 27.0 280 42 22 4.3 2.4
13000 -3.2 26.2 280 50 26 3.5 1.9 | -2.2 28.0 275 41 21 6.8 3.7
12500 -2.5 27.5 280 48 25 5.2 2.8 | -1.1 30.0 275 35 18 7.9 4.3
12000 -1.8 28.8 280 46 24 7.3 4.0 | 0.0 32.0 275 30 16 9.7 5.3
11750 -1.1 30.0 280 44 23 8.8 4.8 | 0.8 33.4 275 30 15 10.4 5.7
11500 -0.5 31.1 280 42 21 8.3 4.6 | 1.6 34.9 275 29 15 10.2 5.6
11250 0.1 32.2 280 39 20 8.5 4.6 | 2.3 36.1 275 29 15 10.3 5.6
11000 0.7 33.3 280 37 19 8.5 4.7 | 3.1 37.6 275 28 15 9.9 5.5
10750 1.3 34.3 275 34 17 9.1 5.0 | 3.8 38.8 275 28 14 10.1 5.6
10500 2.0 35.6 275 31 16 9.5 5.2 | 4.6 40.3 275 27 14 10.4 5.7
10250 2.7 36.9 275 29 15 9.4 5.2 | 5.4 41.7 275 27 14 10.6 5.8
10000 3.5 38.3 270 26 13 10.4 5.7 | 6.2 43.2 275 26 13 11.5 6.3
9750 4.3 39.7 270 24 13 11.4 6.3 | 7.1 44.8 275 25 13 12.6 6.9
9500 5.1 41.2 270 22 12 9.8 5.4 | 8.0 46.4 275 24 12 11.9 6.5
9250 5.9 42.6 265 20 10 13.3 7.3 | 9.0 48.2 275 22 11 19.4 10.6
9000 7.8 46.0 265 15 8 48.5 26.6 | 12.0 53.6 275 18 9 73.5 40.3
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
04/30/2024 at 1500 MDT | 04/30/2024 at 1800 MDT
|
CAPE... 0.0 LI... +1.5 | CAPE... +6.0 LI... -0.2
CINH... 0.0 K Index... -12.4 | CINH... -8.2 K Index... +19.9
|
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 -58.9 -74.0 260 43 22 0.9 0.5 | -58.9 -74.0 265 47 24 0.8 0.4
45000 -57.7 -71.9 265 64 33 -1.4 -0.8 | -57.9 -72.2 265 66 34 -1.7 -1.0
40000 -59.5 -75.1 265 66 34 -1.0 -0.5 | -60.1 -76.2 270 63 33 -1.2 -0.7
38000 -57.5 -71.5 265 62 32 5.2 2.8 | -57.8 -72.0 270 62 32 5.9 3.2
36000 -54.4 -65.9 260 57 30 5.2 2.8 | -54.2 -65.6 265 59 31 5.9 3.2
34000 -50.4 -58.7 260 54 28 8.9 4.9 | -50.1 -58.2 265 58 30 8.6 4.7
32000 -45.1 -49.2 265 54 28 8.9 4.9 | -45.0 -49.0 265 57 29 8.5 4.7
30000 -39.9 -39.8 265 54 28 8.6 4.7 | -39.9 -39.8 265 55 28 8.4 4.6
29000 -37.3 -35.1 270 54 28 8.5 4.7 | -37.4 -35.3 265 54 28 8.4 4.6
28000 -34.1 -29.4 270 53 27 8.5 4.7 | -34.3 -29.7 265 52 27 8.3 4.6
27000 -31.7 -25.1 270 52 27 7.8 4.3 | -31.9 -25.4 265 51 26 7.7 4.2
26000 -29.3 -20.7 265 52 27 7.8 4.3 | -29.6 -21.3 265 51 26 7.7 4.2
25000 -27.0 -16.6 265 51 26 7.9 4.3 | -27.3 -17.1 265 51 26 7.7 4.2
24000 -24.7 -12.5 265 50 26 6.2 3.4 | -25.1 -13.2 265 50 26 5.9 3.2
23000 -22.9 -9.2 265 49 25 6.3 3.5 | -23.4 -10.1 265 49 25 6.1 3.3
22000 -21.0 -5.8 265 48 25 6.4 3.5 | -21.6 -6.9 265 48 25 6.1 3.3
21000 -19.0 -2.2 260 47 24 7.2 3.9 | -19.6 -3.3 260 44 23 7.6 4.2
20000 -16.9 1.6 260 43 22 7.1 3.9 | -17.4 0.7 255 34 18 7.6 4.2
19500 -15.8 3.6 265 42 22 7.1 3.9 | -16.3 2.7 250 30 15 7.7 4.2
19000 -14.7 5.5 265 40 21 7.1 3.9 | -15.3 4.5 240 25 13 7.7 4.2
18500 -13.6 7.5 265 37 19 7.6 4.2 | -14.1 6.6 235 23 12 8.2 4.5
18000 -12.5 9.5 265 33 17 7.6 4.2 | -12.9 8.8 230 22 11 8.2 4.5
17500 -11.3 11.7 265 29 15 7.5 4.1 | -11.7 10.9 225 22 11 7.8 4.3
17000 -10.2 13.6 265 30 16 7.4 4.1 | -10.6 12.9 220 21 11 7.4 4.1
16500 -9.1 15.6 265 32 17 7.4 4.1 | -9.5 14.9 215 20 10 7.3 4.0
16000 -8.0 17.6 265 33 17 7.6 4.2 | -8.3 17.1 215 19 10 9.4 5.1
15500 -6.9 19.6 265 33 17 7.6 4.2 | -6.9 19.6 215 17 9 9.1 5.0
15000 -5.7 21.7 265 33 17 8.1 4.4 | -5.4 22.3 215 16 8 10.7 5.9
14500 -4.0 24.8 265 30 15 5.5 3.0 | -3.1 26.4 220 14 7 6.9 3.8
14000 -3.0 26.6 265 27 14 9.3 5.1 | -1.9 28.6 225 13 7 10.6 5.8
13500 -1.8 28.8 270 24 12 8.8 4.9 | -0.4 31.3 230 12 6 10.1 5.6
13000 -0.5 31.1 270 21 11 9.9 5.4 | 0.9 33.6 235 11 6 8.9 4.9
12500 1.0 33.8 270 21 11 10.0 5.5 | 2.4 36.3 240 11 6 9.9 5.4
12000 2.4 36.3 270 20 10 9.8 5.4 | 3.8 38.8 240 11 5 9.4 5.2
11750 3.2 37.8 270 20 10 10.4 5.7 | 4.5 40.1 245 10 5 10.3 5.7
11500 4.0 39.2 270 19 10 10.3 5.7 | 5.3 41.5 245 10 5 10.1 5.5
11250 4.7 40.5 270 19 10 10.3 5.7 | 6.1 43.0 245 10 5 10.2 5.6
11000 5.5 41.9 270 19 10 10.4 5.7 | 6.8 44.2 245 10 5 10.2 5.6
10750 6.3 43.3 270 19 10 10.3 5.6 | 7.6 45.7 245 10 5 9.9 5.4
10500 7.0 44.6 270 18 9 10.0 5.5 | 8.3 46.9 245 10 5 9.5 5.2
10250 7.8 46.0 270 18 9 10.3 5.7 | 9.0 48.2 250 10 5 9.6 5.3
10000 8.6 47.5 270 17 9 11.0 6.1 | 9.7 49.5 250 9 5 9.7 5.3
9750 9.5 49.1 270 17 9 12.0 6.6 | 10.5 50.9 250 9 5 10.1 5.5
9500 10.3 50.5 270 16 8 10.9 6.0 | 11.2 52.2 250 9 5 10.1 5.6
9250 11.3 52.3 270 15 8 17.8 9.8 | 12.0 53.6 250 8 4 12.5 6.8
9000 14.1 57.4 275 13 7 73.5 40.3 | 13.4 56.1 255 7 4 27.6 15.2
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
________________________________________________________________________________
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