Soaring Guidance
Issued by NWS Pueblo, CO
Issued by NWS Pueblo, CO
079
UXUS97 KPUB 061234
SRGPUB
Soaring Forecast
National Weather Service Pueblo, Colorado
0634 MDT Monday, May 6, 2024
This forecast is for Villa Grove, CO for Monday, May 6, 2024:
If the trigger temperature of 31.6 F/-0.2 C is reached...then
Thermal Soaring Index....................... Fair
Maximum rate of lift........................ 442 ft/min (2.2 m/s)
Maximum height of thermals.................. 17219 ft MSL (8271 ft AGL)
Forecast maximum temperature................... 48.0 F/9.3 C
Time of trigger temperature.................... None
Time of overdevelopment........................ None
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................. 15569 ft MSL (6621 ft AGL)
Thermal soaring outlook for Tuesday 05/07...... Good
Wave Soaring Index............................. Not available
Remarks...
Sunrise/Sunset.................... 06:00:20 / 19:59:58 MDT
Total possible sunshine........... 13 hr 59 min 38 sec (839 min 38 sec)
Altitude of sun at 13:00:09 MDT... 68.57 degrees
Upper air data from numerical model forecast valid on 05/06/2024 at 0600 MDT
Freezing level.................. Entire airmass below 32 F / 0 C
Convective condensation level... 15543 ft MSL (6595 ft AGL)
Lifted condensation level....... 16976 ft MSL (8028 ft AGL)
Lifted index.................... +2.3
K index......................... -14.8
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 -51.6 -60.9 205 21 11 1.1 0.6 M M M M M
45000 -50.0 -58.0 205 30 15 1.7 0.9 M M M M M
40000 -46.6 -51.9 225 46 24 2.1 1.2 M M M M M
38000 -45.8 -50.4 230 54 28 0.6 0.3 M M M M M
36000 -45.4 -49.7 230 61 32 0.6 0.3 M M M M M
34000 -45.0 -49.0 230 69 35 0.9 0.5 M M M M M
32000 -44.3 -47.7 230 79 41 1.2 0.6 M M M M M
30000 -43.6 -46.5 225 90 46 2.8 1.6 M M M M M
29000 -42.0 -43.6 230 90 46 6.0 3.3 20.1 68.2 8.9 M M
28000 -40.2 -40.4 230 90 46 6.0 3.3 18.7 65.6 7.8 M M
27000 -37.9 -36.2 230 89 46 5.8 3.2 17.0 62.7 6.6 M M
26000 -35.6 -32.1 230 89 46 8.4 4.6 16.2 61.2 6.0 M M
25000 -33.1 -27.6 230 89 46 8.4 4.6 15.7 60.3 5.7 M M
24000 -30.6 -23.1 230 89 46 8.4 4.6 15.3 59.6 5.4 M M
23000 -28.0 -18.4 230 86 44 8.5 4.7 14.9 58.8 5.1 M M
22000 -25.5 -13.9 225 83 43 8.5 4.7 14.4 57.9 4.7 M M
21000 -22.9 -9.2 220 79 41 9.0 4.9 14.1 57.3 4.5 M M
20000 -21.2 -6.2 225 77 40 4.8 2.6 12.7 54.8 3.3 M M
19500 -20.5 -4.9 225 76 39 4.8 2.6 11.8 53.3 2.6 M M
19000 -19.7 -3.5 230 75 39 4.8 2.6 11.0 51.8 1.8 M M
18500 -19.0 -2.2 230 74 38 4.7 2.6 10.2 50.4 1.1 M M
18000 -18.2 -0.8 230 71 37 7.1 3.9 9.5 49.2 0.5 M M
17500 -17.1 1.2 225 62 32 7.6 4.2 9.2 48.6 0.2 M M
17000 -15.9 3.4 215 53 27 6.7 3.7 8.9 48.0 -0.1 626 3.2
16500 -15.3 4.5 215 53 27 2.9 1.6 7.9 46.3 -1.0 593 3.0
16000 -14.9 5.2 220 54 28 3.0 1.7 6.9 44.3 -2.0 564 2.9
15500 -14.4 6.1 225 55 28 3.0 1.6 5.8 42.4 -3.0 535 2.7
15000 -13.9 7.0 235 56 29 3.0 1.7 4.7 40.4 -4.0 507 2.6
14500 -13.5 7.7 240 56 29 2.0 1.1 3.6 38.4 -5.1 480 2.4
14000 -13.3 8.1 245 54 28 2.3 1.3 2.3 36.1 -6.3 458 2.3
13500 -13.0 8.6 250 53 27 3.5 1.9 1.1 34.1 -7.5 433 2.2
13000 -12.0 10.4 255 47 24 4.9 2.7 -0.1 31.9 -8.8 384 1.9
12500 -11.1 12.0 260 44 23 9.1 5.0 -0.5 31.1 -9.4 339 1.7
12000 -9.8 14.4 260 42 21 9.2 5.0 -0.6 30.8 -9.6 286 1.5
11750 -9.1 15.6 260 40 21 9.8 5.4 -0.7 30.8 -9.6 258 1.3
11500 -8.4 16.9 260 39 20 9.8 5.4 -0.7 30.8 -9.7 229 1.2
11250 -7.6 18.3 260 37 19 9.7 5.3 -0.7 30.8 -9.7 200 1.0
11000 -6.9 19.6 260 36 18 9.9 5.4 -0.7 30.8 -9.8 171 0.9
10750 -6.2 20.8 260 34 18 9.3 5.1 -0.7 30.8 -9.8 142 0.7
10500 -5.5 22.1 260 33 17 9.4 5.1 -0.7 30.7 -9.9 114 0.6
10250 -4.8 23.4 260 31 16 9.8 5.4 -0.7 30.7 -9.9 85 0.4
10000 -4.1 24.6 255 30 15 10.0 5.5 -0.7 30.7 -9.9 56 0.3
9750 -3.4 25.9 255 28 14 7.3 4.0 -0.7 30.7 -10.0 28 0.1
9500 -3.0 26.6 255 25 13 5.4 3.0 -1.0 30.1 -10.3 8 0.0
9250 -2.4 27.7 255 20 10 9.1 5.0 -1.3 29.7 -10.6 M M
9000 -1.9 28.6 250 15 8 0.6 0.3 -1.4 29.4 -10.8 M M
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 * * * * * *
05/06/2024 at 0900 MDT | 05/06/2024 at 1200 MDT
|
CAPE... +45.1 LI... +0.4 | CAPE... +6.0 LI... +4.0
CINH... 0.0 K Index... -14.0 | CINH... 0.0 K Index... -8.7
|
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 -50.7 -59.3 240 20 10 -0.4 -0.2 | -50.3 -58.5 260 20 10 1.9 1.0
45000 -51.3 -60.3 230 31 16 0.9 0.5 | -47.5 -53.5 255 41 21 1.3 0.7
40000 -47.7 -53.9 220 42 21 2.3 1.3 | -46.9 -52.4 230 44 23 0.4 0.2
38000 -46.2 -51.2 225 44 22 2.7 1.5 | -46.3 -51.3 230 45 23 1.8 1.0
36000 -44.6 -48.3 230 44 23 2.7 1.5 | -45.3 -49.5 245 45 23 1.8 1.0
34000 -42.9 -45.2 235 45 23 2.7 1.5 | -44.2 -47.6 255 47 24 1.5 0.8
32000 -41.4 -42.5 240 57 29 2.6 1.4 | -44.0 -47.2 260 56 29 0.2 0.1
30000 -39.8 -39.6 240 70 36 2.8 1.5 | -43.9 -47.0 260 66 34 0.3 0.2
29000 -38.5 -37.3 240 73 37 4.7 2.6 | -42.6 -44.7 260 68 35 5.0 2.7
28000 -37.1 -34.8 240 75 38 4.7 2.6 | -40.8 -41.4 260 71 37 5.0 2.7
27000 -35.4 -31.7 240 77 40 4.7 2.6 | -39.3 -38.7 260 73 38 4.9 2.7
26000 -33.7 -28.7 240 78 40 6.4 3.5 | -37.5 -35.5 260 75 39 6.7 3.7
25000 -31.8 -25.2 240 79 40 6.4 3.5 | -35.5 -31.9 260 76 39 6.8 3.7
24000 -29.8 -21.6 240 79 41 6.4 3.5 | -33.5 -28.3 265 78 40 6.8 3.7
23000 -28.4 -19.1 240 78 40 1.8 1.0 | -31.2 -24.2 265 78 40 8.5 4.7
22000 -27.8 -18.0 245 75 38 2.0 1.1 | -28.6 -19.5 265 77 39 8.6 4.7
21000 -27.2 -17.0 245 71 37 2.0 1.1 | -26.1 -15.0 265 75 39 8.8 4.8
20000 -26.7 -16.1 250 66 34 1.8 1.0 | -24.1 -11.4 270 74 38 5.6 3.1
19500 -26.4 -15.5 250 62 32 1.8 1.0 | -23.3 -9.9 270 73 37 5.6 3.1
19000 -26.1 -15.0 255 59 30 1.9 1.0 | -22.4 -8.3 270 72 37 5.6 3.1
18500 -25.9 -14.6 260 55 28 2.0 1.1 | -21.6 -6.9 270 71 36 5.6 3.1
18000 -25.6 -14.1 260 52 27 4.8 2.7 | -20.8 -5.4 270 69 36 4.6 2.5
17500 -24.5 -12.1 260 50 26 7.2 4.0 | -20.2 -4.4 275 66 34 4.4 2.4
17000 -23.4 -10.1 260 48 25 7.4 4.1 | -19.5 -3.1 275 62 32 4.3 2.4
16500 -22.3 -8.1 265 48 25 7.4 4.1 | -18.9 -2.0 275 60 31 4.2 2.3
16000 -21.2 -6.2 265 48 25 7.3 4.0 | -18.3 -0.9 275 59 30 4.2 2.3
15500 -20.0 -4.0 265 48 24 9.2 5.0 | -17.6 0.3 275 57 29 4.2 2.3
15000 -18.6 -1.5 265 44 23 9.3 5.1 | -17.0 1.4 275 54 28 4.2 2.3
14500 -17.3 0.9 265 42 22 6.6 3.6 | -16.4 2.5 275 53 27 5.0 2.8
14000 -16.5 2.3 265 44 23 7.3 4.0 | -15.6 3.9 275 51 26 6.1 3.3
13500 -14.8 5.4 265 49 25 6.4 3.5 | -14.6 5.7 270 47 24 9.1 5.0
13000 -13.8 7.2 265 51 26 6.2 3.4 | -12.4 9.7 270 44 22 8.6 4.7
12500 -12.8 9.0 265 51 26 8.4 4.6 | -11.0 12.2 270 43 22 10.1 5.5
12000 -11.6 11.1 265 49 25 8.1 4.4 | -9.5 14.9 270 42 22 10.6 5.8
11750 -11.0 12.2 265 47 24 9.3 5.1 | -8.7 16.3 270 41 21 10.8 5.9
11500 -10.2 13.6 265 46 24 10.5 5.8 | -8.0 17.6 270 41 21 10.0 5.5
11250 -9.5 14.9 265 45 23 10.3 5.7 | -7.2 19.0 270 40 21 10.3 5.7
11000 -8.7 16.3 265 44 22 10.4 5.7 | -6.4 20.5 270 40 21 9.9 5.4
10750 -7.9 17.8 265 42 22 10.0 5.5 | -5.7 21.7 270 40 20 10.2 5.6
10500 -7.2 19.0 265 42 21 10.5 5.7 | -4.9 23.2 270 39 20 11.4 6.2
10250 -6.4 20.5 265 40 21 11.2 6.1 | -4.0 24.8 270 38 20 11.7 6.4
10000 -5.5 22.1 265 39 20 10.9 6.0 | -3.1 26.4 270 37 19 11.3 6.2
9750 -4.7 23.5 265 37 19 11.3 6.2 | -2.3 27.9 270 36 19 12.0 6.6
9500 -3.7 25.3 265 34 18 17.3 9.5 | -1.1 30.0 270 34 17 21.6 11.9
9250 -2.1 28.2 265 29 15 25.9 14.2 | 1.0 33.8 270 29 15 35.0 19.2
9000 -0.4 31.3 265 23 12 11.0 6.1 | 3.2 37.8 270 25 13 12.0 6.6
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
05/06/2024 at 1500 MDT | 05/06/2024 at 1800 MDT
|
CAPE... +2.3 LI... +2.1 | CAPE... +5.2 LI... +1.3
CINH... 0.0 K Index... +1.3 | CINH... 0.0 K Index... +5.0
|
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 -51.7 -61.1 250 28 14 2.3 1.3 | -52.1 -61.8 245 23 12 2.5 1.4
45000 -48.3 -54.9 260 39 20 1.8 1.0 | -48.3 -54.9 265 29 15 1.7 0.9
40000 -46.4 -51.5 255 51 26 1.2 0.6 | -47.1 -52.8 280 53 27 0.8 0.4
38000 -45.8 -50.4 255 53 27 0.9 0.5 | -46.5 -51.7 280 59 30 1.2 0.6
36000 -45.2 -49.4 260 54 28 0.9 0.5 | -45.8 -50.4 280 62 32 1.2 0.6
34000 -44.7 -48.5 270 56 29 0.7 0.4 | -45.1 -49.2 280 64 33 1.0 0.6
32000 -44.8 -48.6 270 55 29 -0.3 -0.2 | -44.6 -48.3 280 59 30 0.7 0.4
30000 -45.0 -49.0 270 55 28 -0.1 -0.1 | -44.2 -47.6 280 53 27 1.2 0.6
29000 -44.0 -47.2 270 57 29 4.3 2.4 | -43.2 -45.8 285 51 26 3.7 2.0
28000 -42.4 -44.3 270 59 31 4.3 2.4 | -41.8 -43.2 285 49 25 3.7 2.0
27000 -41.1 -42.0 265 62 32 4.2 2.3 | -40.7 -41.3 290 48 25 3.5 1.9
26000 -39.1 -38.4 265 62 32 7.8 4.3 | -38.9 -38.0 290 48 25 7.3 4.0
25000 -36.8 -34.2 270 62 32 7.8 4.3 | -36.8 -34.2 290 48 25 7.3 4.0
24000 -34.5 -30.1 270 62 32 7.8 4.3 | -34.6 -30.3 290 49 25 7.3 4.0
23000 -32.1 -25.8 270 61 32 8.3 4.5 | -32.2 -26.0 290 50 26 8.3 4.6
22000 -29.6 -21.3 270 61 31 8.3 4.6 | -29.7 -21.5 285 50 26 8.4 4.6
21000 -27.1 -16.8 270 60 31 8.5 4.7 | -27.2 -17.0 285 51 26 8.5 4.7
20000 -25.0 -13.0 275 60 31 6.7 3.7 | -25.1 -13.2 285 51 26 6.7 3.7
19500 -24.0 -11.2 275 60 31 6.7 3.7 | -24.1 -11.4 285 51 26 6.7 3.7
19000 -23.0 -9.4 275 60 31 6.8 3.7 | -23.1 -9.6 285 51 26 6.7 3.7
18500 -22.0 -7.6 275 61 31 6.8 3.7 | -22.1 -7.8 285 51 26 6.8 3.7
18000 -21.0 -5.8 275 60 31 6.1 3.3 | -21.2 -6.2 285 51 26 6.4 3.5
17500 -20.1 -4.2 275 59 30 6.0 3.3 | -20.2 -4.4 285 50 26 6.4 3.5
17000 -19.2 -2.6 280 58 30 6.3 3.5 | -19.3 -2.7 285 50 26 6.3 3.5
16500 -18.2 -0.8 280 56 29 6.8 3.7 | -18.3 -0.9 285 50 26 6.3 3.5
16000 -17.2 1.0 280 55 28 6.8 3.7 | -17.4 0.7 285 49 25 6.4 3.5
15500 -16.2 2.8 280 54 28 6.0 3.3 | -16.4 2.5 285 49 25 7.4 4.1
15000 -15.3 4.5 275 53 27 6.0 3.3 | -15.3 4.5 285 49 25 7.2 3.9
14500 -14.4 6.1 275 51 26 6.5 3.6 | -13.5 7.7 280 46 24 8.5 4.7
14000 -12.9 8.8 270 44 23 7.9 4.4 | -12.4 9.7 275 44 22 8.0 4.4
13500 -11.4 11.5 270 42 22 11.6 6.3 | -10.9 12.4 275 42 22 11.0 6.0
13000 -9.9 14.2 270 41 21 8.1 4.5 | -9.4 15.1 275 41 21 8.6 4.7
12500 -8.6 16.5 270 40 21 10.3 5.6 | -8.1 17.4 275 40 21 10.1 5.5
12000 -7.1 19.2 270 39 20 10.2 5.6 | -6.6 20.1 275 39 20 10.2 5.6
11750 -6.3 20.7 270 39 20 10.3 5.6 | -5.8 21.6 275 39 20 10.1 5.5
11500 -5.6 21.9 270 38 20 10.1 5.5 | -5.1 22.8 275 38 20 9.7 5.3
11250 -4.8 23.4 270 38 20 10.1 5.6 | -4.3 24.3 275 38 20 9.9 5.4
11000 -4.0 24.8 270 37 19 10.1 5.5 | -3.6 25.5 270 38 19 9.8 5.4
10750 -3.3 26.1 270 37 19 10.4 5.7 | -2.9 26.8 270 37 19 10.4 5.7
10500 -2.5 27.5 270 36 19 10.8 5.9 | -2.1 28.2 270 36 19 11.0 6.0
10250 -1.7 28.9 270 36 18 10.7 5.9 | -1.2 29.8 270 35 18 10.9 6.0
10000 -0.9 30.4 270 35 18 10.8 5.9 | -0.4 31.3 270 35 18 10.9 6.0
9750 -0.0 32.0 270 34 17 13.6 7.4 | 0.4 32.7 270 34 17 11.5 6.3
9500 1.3 34.3 270 32 16 22.6 12.4 | 1.4 34.5 270 31 16 15.8 8.6
9250 3.3 37.9 270 28 14 31.6 17.3 | 2.8 37.0 270 26 14 21.0 11.5
9000 5.4 41.7 270 23 12 17.4 9.5 | 4.2 39.6 270 22 11 12.2 6.7
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