Soaring Guidance
Issued by NWS Pueblo, CO
Issued by NWS Pueblo, CO
454
UXUS97 KPUB 071233
SRGPUB
Soaring Forecast
National Weather Service Pueblo, Colorado
0633 MDT Tuesday, May 7, 2024
This forecast is for Villa Grove, CO for Tuesday, May 7, 2024:
If the trigger temperature of 37.5 F/3.1 C is reached...then
Thermal Soaring Index....................... Good
Maximum rate of lift........................ 1064 ft/min (5.4 m/s)
Maximum height of thermals.................. 20697 ft MSL (11746 ft AGL)
Forecast maximum temperature................... 54.0 F/12.7 C
Time of trigger temperature.................... 0745 MDT
Time of overdevelopment........................ None
Middle/high clouds during soaring window....... None
Surface winds during soaring window............ Between 20 mph and 30 mph
Height of the -3 thermal index................. 19181 ft MSL (10230 ft AGL)
Thermal soaring outlook for Wednesday 05/08.... Good
Wave Soaring Index............................. Not available
Remarks...
Sunrise/Sunset.................... 05:59:17 / 20:00:53 MDT
Total possible sunshine........... 14 hr 1 min 36 sec (841 min 36 sec)
Altitude of sun at 13:00:05 MDT... 68.84 degrees
Upper air data from numerical model forecast valid on 05/07/2024 at 0600 MDT
Freezing level.................. Entire airmass below 32 F / 0 C
Convective condensation level... 14547 ft MSL (5596 ft AGL)
Lifted condensation level....... 17865 ft MSL (8914 ft AGL)
Lifted index.................... +2.2
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 -53.7 -64.7 255 39 20 2.8 1.5 M M M M M
45000 -49.6 -57.3 250 43 22 1.2 0.7 M M M M M
40000 -49.2 -56.6 275 60 31 0.2 0.1 M M M M M
38000 -49.1 -56.4 275 73 37 0.1 0.1 M M M M M
36000 -49.0 -56.2 275 90 47 0.1 0.1 M M M M M
34000 -48.7 -55.7 275 107 55 4.4 2.4 M M M M M
32000 -45.5 -49.9 270 114 59 5.4 3.0 M M M M M
30000 -42.2 -44.0 270 120 62 7.1 3.9 23.3 74.0 8.7 M M
29000 -39.9 -39.8 270 118 61 7.6 4.2 22.4 72.3 8.0 M M
28000 -37.7 -35.9 275 116 60 7.6 4.2 21.5 70.8 7.4 M M
27000 -35.4 -31.7 275 113 58 7.6 4.2 20.8 69.5 7.0 M M
26000 -32.9 -27.2 275 109 56 6.3 3.4 19.4 67.0 5.9 M M
25000 -31.0 -23.8 275 105 54 6.3 3.4 18.1 64.7 4.9 M M
24000 -29.1 -20.4 280 100 52 6.3 3.5 17.0 62.6 4.0 M M
23000 -27.4 -17.3 280 96 49 5.6 3.1 15.6 60.0 2.8 M M
22000 -25.7 -14.3 280 91 47 5.6 3.1 14.1 57.4 1.6 M M
21000 -24.1 -11.4 285 87 45 5.7 3.1 12.8 55.0 0.4 M M
20000 -22.9 -9.2 285 82 42 3.5 1.9 10.7 51.3 -1.4 1021 5.2
19500 -22.4 -8.3 285 80 41 3.5 1.9 9.7 49.4 -2.4 990 5.0
19000 -21.8 -7.2 285 77 40 3.5 1.9 8.6 47.5 -3.3 960 4.9
18500 -21.3 -6.3 285 75 39 3.3 1.8 7.6 45.7 -4.2 930 4.7
18000 -20.6 -5.1 285 73 37 6.4 3.5 6.8 44.3 -5.0 894 4.5
17500 -19.7 -3.5 285 71 36 6.4 3.5 6.3 43.3 -5.6 851 4.3
17000 -18.8 -1.8 285 68 35 7.2 3.9 5.7 42.3 -6.1 809 4.1
16500 -17.6 0.3 280 60 31 7.9 4.4 5.4 41.7 -6.4 758 3.9
16000 -16.4 2.5 275 51 26 8.0 4.4 5.1 41.2 -6.7 708 3.6
15500 -15.2 4.6 275 48 25 7.9 4.3 4.8 40.7 -7.1 659 3.3
15000 -14.1 6.6 270 46 24 7.9 4.3 4.5 40.2 -7.4 609 3.1
14500 -12.9 8.8 270 47 24 8.4 4.6 4.3 39.7 -7.7 559 2.8
14000 -11.7 10.9 265 50 26 7.1 3.9 4.0 39.2 -8.1 509 2.6
13500 -10.6 12.9 265 54 28 8.7 4.7 3.6 38.5 -8.5 462 2.3
13000 -8.7 16.3 265 59 30 8.3 4.6 3.4 38.2 -8.8 381 1.9
12500 -7.5 18.5 265 59 30 8.1 4.4 3.2 37.7 -9.1 330 1.7
12000 -6.3 20.7 265 57 29 8.4 4.6 2.9 37.2 -9.4 280 1.4
11750 -5.7 21.7 265 55 28 8.3 4.5 2.8 37.1 -9.5 254 1.3
11500 -5.1 22.8 265 52 27 7.8 4.3 2.7 36.8 -9.7 229 1.2
11250 -4.5 23.9 260 50 26 8.0 4.4 2.5 36.5 -9.9 204 1.0
11000 -3.9 25.0 260 48 25 7.5 4.1 2.4 36.3 -10.1 179 0.9
10750 -3.4 25.9 260 46 24 5.6 3.1 2.2 35.9 -10.3 157 0.8
10500 -3.0 26.6 255 43 22 5.2 2.9 1.8 35.2 -10.7 138 0.7
10250 -2.6 27.3 255 39 20 6.0 3.3 1.5 34.7 -11.1 119 0.6
10000 -2.2 28.0 255 36 18 5.0 2.7 1.2 34.1 -11.4 99 0.5
9750 -2.0 28.4 250 32 16 0.9 0.5 0.7 33.3 -11.9 84 0.4
9500 -2.1 28.2 250 27 14 -2.1 -1.1 -0.1 31.8 -12.8 79 0.4
9250 -2.2 28.0 245 20 10 -0.8 -0.4 -1.0 30.3 -13.6 76 0.4
9000 -2.3 27.9 240 13 7 -4.7 -2.6 -1.8 28.7 -14.5 72 0.4
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 * * * * * *
05/07/2024 at 0900 MDT | 05/07/2024 at 1200 MDT
|
CAPE... +65.4 LI... -0.8 | CAPE... +134.6 LI... -1.5
CINH... -1.1 K Index... +3.8 | CINH... 0.0 K Index... +0.6
|
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 -54.0 -65.2 250 32 16 2.7 1.5 | -54.4 -65.9 245 34 18 2.1 1.1
45000 -50.0 -58.0 260 48 25 1.0 0.5 | -51.3 -60.3 255 54 28 0.7 0.4
40000 -49.7 -57.5 270 75 38 0.2 0.1 | -51.0 -59.8 265 74 38 0.2 0.1
38000 -49.5 -57.1 270 86 44 0.4 0.2 | -50.4 -58.7 265 86 44 1.9 1.0
36000 -49.2 -56.6 270 97 50 0.4 0.2 | -49.2 -56.6 270 101 52 1.9 1.1
34000 -48.7 -55.7 275 109 56 5.4 2.9 | -47.8 -54.0 270 115 59 6.1 3.3
32000 -45.2 -49.4 270 113 58 6.0 3.3 | -44.2 -47.6 270 117 60 6.0 3.3
30000 -41.5 -42.7 265 117 60 7.6 4.2 | -40.6 -41.1 265 120 62 6.8 3.7
29000 -39.1 -38.4 265 117 60 7.9 4.3 | -38.6 -37.5 265 119 61 6.8 3.7
28000 -36.2 -33.2 265 117 60 7.9 4.3 | -36.0 -32.8 265 117 60 6.8 3.7
27000 -33.8 -28.8 265 117 60 7.9 4.3 | -34.0 -29.2 265 116 60 6.7 3.7
26000 -32.1 -25.8 270 113 58 5.5 3.0 | -32.2 -26.0 265 112 58 5.6 3.1
25000 -30.4 -22.7 270 109 56 5.5 3.0 | -30.6 -23.1 265 108 56 5.6 3.1
24000 -28.7 -19.7 275 105 54 5.6 3.1 | -28.9 -20.0 265 104 54 5.6 3.1
23000 -27.2 -17.0 275 100 51 4.9 2.7 | -27.1 -16.8 270 100 51 6.1 3.3
22000 -25.8 -14.4 275 94 48 4.9 2.7 | -25.3 -13.5 270 96 49 6.1 3.3
21000 -24.3 -11.7 275 88 45 4.9 2.7 | -23.4 -10.1 270 92 47 6.0 3.3
20000 -23.1 -9.6 275 82 42 3.8 2.1 | -22.3 -8.1 270 85 44 3.3 1.8
19500 -22.5 -8.5 280 79 41 3.8 2.1 | -21.8 -7.2 270 82 42 3.4 1.9
19000 -22.0 -7.6 280 76 39 3.8 2.1 | -21.3 -6.3 270 79 41 3.4 1.9
18500 -21.4 -6.5 280 74 38 3.4 1.9 | -20.8 -5.4 270 75 39 3.1 1.7
18000 -20.6 -5.1 280 71 37 8.0 4.4 | -20.1 -4.2 270 73 37 7.0 3.8
17500 -19.5 -3.1 275 69 36 7.9 4.3 | -19.1 -2.4 265 70 36 6.9 3.8
17000 -18.3 -0.9 275 67 35 8.2 4.5 | -18.1 -0.6 265 68 35 8.1 4.4
16500 -17.0 1.4 275 64 33 8.4 4.6 | -16.8 1.8 265 67 34 9.1 5.0
16000 -15.8 3.6 275 61 31 8.4 4.6 | -15.4 4.3 265 65 34 9.2 5.0
15500 -14.6 5.7 270 58 30 7.8 4.3 | -14.1 6.6 265 63 33 9.6 5.3
15000 -13.5 7.7 270 56 29 7.7 4.2 | -12.7 9.1 260 61 31 9.8 5.4
14500 -11.4 11.5 265 57 29 8.8 4.8 | -10.8 12.6 260 58 30 8.0 4.4
14000 -10.4 13.3 265 57 30 6.8 3.7 | -9.6 14.7 260 56 29 8.6 4.7
13500 -9.2 15.4 265 57 30 10.0 5.5 | -8.3 17.1 260 52 27 8.9 4.9
13000 -8.1 17.4 260 58 30 4.7 2.6 | -7.0 19.4 260 47 24 8.8 4.8
12500 -7.1 19.2 260 55 28 8.2 4.5 | -5.6 21.9 260 44 22 10.4 5.7
12000 -6.0 21.2 260 51 27 8.1 4.5 | -4.1 24.6 260 41 21 9.8 5.4
11750 -5.4 22.3 260 49 25 9.0 4.9 | -3.4 25.9 260 40 20 9.6 5.3
11500 -4.7 23.5 260 47 24 9.3 5.1 | -2.6 27.3 260 39 20 10.1 5.6
11250 -4.0 24.8 260 44 23 9.2 5.0 | -1.9 28.6 260 38 20 9.8 5.4
11000 -3.3 26.1 255 42 21 9.5 5.2 | -1.1 30.0 260 38 19 10.6 5.8
10750 -2.6 27.3 255 39 20 10.1 5.5 | -0.3 31.5 260 37 19 11.3 6.2
10500 -1.8 28.8 255 37 19 10.0 5.5 | 0.5 32.9 260 36 19 10.9 6.0
10250 -1.1 30.0 255 35 18 9.8 5.4 | 1.3 34.3 260 36 18 10.9 6.0
10000 -0.4 31.3 255 33 17 10.0 5.5 | 2.1 35.8 260 35 18 10.5 5.8
9750 0.4 32.7 250 31 16 12.1 6.6 | 3.0 37.4 260 34 17 12.9 7.1
9500 1.5 34.7 250 28 15 16.8 9.2 | 4.2 39.6 260 31 16 21.8 11.9
9250 2.9 37.2 250 24 12 20.5 11.2 | 6.2 43.2 265 27 14 30.1 16.5
9000 4.3 39.7 250 19 10 15.1 8.3 | 8.1 46.6 265 23 12 17.2 9.4
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
05/07/2024 at 1500 MDT | 05/07/2024 at 1800 MDT
|
CAPE... +172.0 LI... -2.5 | CAPE... +138.2 LI... -1.3
CINH... 0.0 K Index... +10.7 | CINH... -0.5 K Index... +17.2
|
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 -54.2 -65.6 240 29 15 1.7 0.9 | -54.0 -65.2 250 29 15 1.2 0.7
45000 -51.7 -61.1 245 43 22 0.8 0.4 | -52.2 -62.0 255 45 23 1.3 0.7
40000 -51.1 -60.0 260 69 36 0.4 0.2 | -50.0 -58.0 260 68 35 1.4 0.8
38000 -50.3 -58.5 265 84 43 2.1 1.2 | -49.0 -56.2 265 81 42 1.9 1.1
36000 -49.0 -56.2 265 103 53 2.1 1.2 | -47.9 -54.2 265 100 52 1.9 1.1
34000 -47.5 -53.5 270 120 62 5.8 3.2 | -46.6 -51.9 265 118 61 4.7 2.6
32000 -44.1 -47.4 265 119 61 5.7 3.1 | -43.5 -46.3 265 118 61 5.0 2.8
30000 -40.7 -41.3 260 118 61 6.5 3.6 | -40.5 -40.9 265 118 61 5.1 2.8
29000 -38.7 -37.7 265 115 59 6.6 3.6 | -38.7 -37.7 265 111 57 5.0 2.7
28000 -36.3 -33.3 265 112 58 6.6 3.6 | -37.2 -35.0 265 106 55 5.0 2.7
27000 -34.3 -29.7 265 109 56 6.5 3.6 | -35.7 -32.3 265 101 52 5.0 2.7
26000 -32.6 -26.7 265 105 54 5.6 3.1 | -34.1 -29.4 265 96 49 5.5 3.0
25000 -30.9 -23.6 265 100 52 5.6 3.1 | -32.5 -26.5 265 91 47 5.5 3.0
24000 -29.2 -20.6 265 96 49 5.6 3.0 | -30.8 -23.4 265 86 45 5.4 3.0
23000 -27.3 -17.1 265 87 45 6.8 3.7 | -29.1 -20.4 265 82 42 5.9 3.3
22000 -25.3 -13.5 260 76 39 6.8 3.7 | -27.4 -17.3 260 79 40 6.0 3.3
21000 -23.2 -9.8 255 66 34 6.6 3.6 | -25.6 -14.1 260 75 39 6.1 3.3
20000 -22.0 -7.6 255 65 33 3.7 2.0 | -23.3 -9.9 255 66 34 8.4 4.6
19500 -21.5 -6.7 255 65 34 3.8 2.1 | -22.0 -7.6 255 62 32 8.4 4.6
19000 -20.9 -5.6 255 66 34 3.7 2.1 | -20.8 -5.4 250 57 30 8.4 4.6
18500 -20.4 -4.7 255 66 34 3.2 1.7 | -19.6 -3.3 245 53 27 8.4 4.6
18000 -19.5 -3.1 255 65 33 9.6 5.3 | -18.3 -0.9 245 50 26 9.1 5.0
17500 -18.1 -0.6 255 62 32 9.0 5.0 | -17.0 1.4 245 49 25 9.0 5.0
17000 -16.8 1.8 255 59 31 9.0 4.9 | -15.6 3.9 245 48 25 8.5 4.7
16500 -15.5 4.1 255 57 29 9.0 4.9 | -14.5 5.9 245 46 23 7.9 4.4
16000 -14.2 6.4 255 54 28 9.1 5.0 | -12.7 9.1 240 42 22 7.6 4.2
15500 -12.8 9.0 255 52 27 9.4 5.2 | -11.6 11.1 245 42 21 7.5 4.1
15000 -11.5 11.3 255 49 25 9.6 5.3 | -10.5 13.1 245 41 21 7.1 3.9
14500 -9.6 14.7 255 44 23 9.8 5.4 | -9.6 14.7 250 39 20 6.9 3.8
14000 -7.9 17.8 255 42 22 10.8 5.9 | -8.5 16.7 250 37 19 7.8 4.3
13500 -6.4 20.5 260 40 21 9.5 5.2 | -7.2 19.0 255 34 18 9.3 5.1
13000 -5.0 23.0 260 39 20 10.0 5.5 | -6.2 20.8 260 32 16 4.4 2.4
12500 -3.5 25.7 260 38 19 10.1 5.5 | -5.1 22.8 265 29 15 10.5 5.7
12000 -2.0 28.4 260 37 19 9.6 5.2 | -3.6 25.5 265 28 14 7.5 4.1
11750 -1.3 29.7 260 36 19 9.6 5.3 | -3.2 26.2 265 27 14 7.6 4.1
11500 -0.5 31.1 260 36 19 10.3 5.7 | -2.4 27.7 265 26 13 11.2 6.2
11250 0.2 32.4 260 36 18 10.3 5.6 | -1.6 29.1 265 26 13 10.4 5.7
11000 1.0 33.8 260 35 18 9.8 5.4 | -0.8 30.6 270 25 13 11.1 6.1
10750 1.7 35.1 260 35 18 10.2 5.6 | -0.0 32.0 270 25 13 9.3 5.1
10500 2.5 36.5 260 34 17 11.0 6.0 | 0.6 33.1 270 24 12 9.1 5.0
10250 3.3 37.9 260 33 17 10.9 6.0 | 1.4 34.5 270 24 12 10.8 5.9
10000 4.1 39.4 260 33 17 10.4 5.7 | 2.2 36.0 270 23 12 9.7 5.3
9750 5.0 41.0 265 32 16 13.0 7.2 | 2.9 37.2 270 23 12 12.4 6.8
9500 6.2 43.2 265 30 15 21.5 11.8 | 4.0 39.2 270 21 11 16.6 9.1
9250 8.1 46.6 265 26 13 28.0 15.4 | 5.3 41.5 270 18 9 16.1 8.8
9000 10.0 50.0 265 22 11 18.8 10.3 | 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