Soaring Guidance
Issued by NWS Pueblo, CO
Issued by NWS Pueblo, CO
744
UXUS97 KPUB 091240
SRGPUB
Soaring Forecast
National Weather Service Pueblo, Colorado
0640 MDT Thursday, May 9, 2024
This forecast is for Villa Grove, CO for Thursday, May 9, 2024:
If the trigger temperature of 38.1 F/3.4 C is reached...then
Thermal Soaring Index....................... Fair
Maximum rate of lift........................ 263 ft/min (1.3 m/s)
Maximum height of thermals.................. 16041 ft MSL (7073 ft AGL)
Forecast maximum temperature................... 44.0 F/7.1 C
Time of trigger temperature.................... 1030 MDT
Time of overdevelopment........................ None
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................. 13337 ft MSL (4369 ft AGL)
Thermal soaring outlook for Friday 05/10....... Poor
Wave Soaring Index............................. Not available
Remarks...
Sunrise/Sunset.................... 05:57:16 / 20:02:44 MDT
Total possible sunshine........... 14 hr 5 min 27 sec (845 min 27 sec)
Altitude of sun at 13:00:00 MDT... 69.37 degrees
Upper air data from numerical model forecast valid on 05/09/2024 at 0600 MDT
Freezing level.................. Entire airmass below 32 F / 0 C
Convective condensation level... 16924 ft MSL (7956 ft AGL)
Lifted condensation level....... 16759 ft MSL (7791 ft AGL)
Lifted index.................... +4.4
K index......................... +0.7
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 -53.4 -64.1 240 11 6 2.9 1.6 M M M M M
45000 -49.1 -56.4 225 21 11 1.2 0.7 M M M M M
40000 -49.2 -56.6 250 31 16 -0.1 -0.0 M M M M M
38000 -49.4 -56.9 250 37 19 -0.8 -0.4 M M M M M
36000 -49.9 -57.8 250 43 22 -0.8 -0.4 M M M M M
34000 -50.2 -58.4 250 50 26 2.9 1.6 M M M M M
32000 -48.0 -54.4 250 52 27 3.6 2.0 M M M M M
30000 -45.7 -50.3 250 54 28 7.5 4.1 19.3 66.8 9.8 M M
29000 -42.7 -44.9 250 51 26 7.9 4.3 18.3 64.9 9.2 M M
28000 -40.4 -40.7 250 49 25 7.9 4.3 17.6 63.6 8.7 M M
27000 -38.1 -36.6 245 46 24 7.7 4.2 17.0 62.6 8.3 M M
26000 -35.8 -32.4 245 44 23 7.4 4.1 16.1 60.9 7.7 M M
25000 -33.6 -28.5 245 42 21 7.4 4.1 15.2 59.3 7.0 M M
24000 -31.4 -24.5 240 39 20 7.4 4.1 14.5 58.0 6.5 M M
23000 -29.4 -20.9 240 38 19 6.7 3.7 13.4 56.1 5.6 M M
22000 -27.4 -17.3 240 36 19 6.7 3.7 12.3 54.1 4.8 M M
21000 -25.3 -13.5 240 35 18 6.8 3.7 11.4 52.5 4.0 M M
20000 -23.3 -9.9 240 32 16 6.8 3.7 10.3 50.5 3.1 M M
19500 -22.3 -8.1 245 31 16 6.8 3.7 9.8 49.6 2.6 M M
19000 -21.3 -6.3 245 29 15 6.8 3.7 9.3 48.7 2.2 M M
18500 -20.3 -4.5 245 28 14 6.9 3.8 8.8 47.9 1.8 M M
18000 -19.2 -2.6 245 28 15 7.4 4.1 8.4 47.1 1.5 M M
17500 -18.1 -0.6 245 29 15 7.4 4.0 8.0 46.4 1.1 M M
17000 -17.0 1.4 240 29 15 7.7 4.2 7.7 45.8 0.8 M M
16500 -15.8 3.6 235 28 14 7.7 4.2 7.3 45.2 0.4 M M
16000 -14.7 5.5 230 27 14 5.6 3.1 7.0 44.5 0.1 M M
15500 -14.1 6.6 220 23 12 4.3 2.3 6.0 42.8 -0.8 634 3.2
15000 -13.5 7.7 210 20 10 5.1 2.8 5.1 41.2 -1.6 602 3.1
14500 -11.9 10.6 190 19 10 7.5 4.1 4.6 40.2 -2.2 530 2.7
14000 -11.0 12.2 180 19 10 7.0 3.8 4.0 39.2 -2.7 487 2.5
13500 -9.7 14.5 175 20 10 8.1 4.5 3.8 38.8 -3.0 435 2.2
13000 -8.4 16.9 165 20 10 7.4 4.1 3.6 38.6 -3.2 382 1.9
12500 -7.6 18.3 155 19 10 5.8 3.2 3.0 37.4 -3.8 342 1.7
12000 -6.8 19.8 140 18 9 5.7 3.1 2.4 36.3 -4.5 303 1.5
11750 -6.4 20.5 135 17 9 5.6 3.1 2.1 35.7 -4.8 283 1.4
11500 -5.9 21.4 130 16 8 5.7 3.1 1.7 35.1 -5.1 263 1.3
11250 -5.5 22.1 125 15 8 5.5 3.0 1.4 34.6 -5.5 243 1.2
11000 -5.1 22.8 115 14 7 6.7 3.7 1.1 34.0 -5.8 223 1.1
10750 -4.5 23.9 110 14 7 7.4 4.0 0.9 33.7 -6.0 199 1.0
10500 -4.0 24.8 105 13 7 6.6 3.6 0.7 33.3 -6.2 177 0.9
10250 -3.5 25.7 100 12 6 6.5 3.6 0.5 32.9 -6.5 155 0.8
10000 -3.1 26.4 095 11 6 4.9 2.7 0.2 32.4 -6.8 134 0.7
9750 -2.8 27.0 090 10 5 3.6 2.0 -0.2 31.6 -7.2 118 0.6
9500 -2.5 27.5 080 9 4 4.0 2.2 -0.7 30.8 -7.7 102 0.5
9250 -2.3 27.9 065 7 4 1.5 0.8 -1.2 29.9 -8.2 88 0.4
9000 -2.6 27.3 020 4 2 -11.3 -6.2 -2.2 28.1 -9.3 89 0.5
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 * * * * * *
05/09/2024 at 0900 MDT | 05/09/2024 at 1200 MDT
|
CAPE... 0.0 LI... -0.2 | CAPE... +22.6 LI... +1.2
CINH... 0.0 K Index... +9.1 | CINH... 0.0 K Index... +14.0
|
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 -53.2 -63.8 245 8 4 2.2 1.2 | -53.5 -64.3 250 10 5 2.7 1.5
45000 -49.8 -57.6 245 17 9 1.4 0.7 | -49.5 -57.1 250 18 9 0.0 0.0
40000 -47.6 -53.7 260 23 12 1.4 0.8 | -49.1 -56.4 250 23 12 0.3 0.1
38000 -47.8 -54.0 255 31 16 -2.1 -1.1 | -49.4 -56.9 250 34 17 -1.1 -0.6
36000 -49.1 -56.4 245 45 23 -2.1 -1.1 | -50.1 -58.2 250 53 27 -1.1 -0.6
34000 -50.1 -58.2 240 59 30 2.5 1.3 | -50.5 -58.9 250 71 37 3.6 2.0
32000 -48.2 -54.8 240 57 29 3.3 1.8 | -47.8 -54.0 245 70 36 4.0 2.2
30000 -45.3 -49.5 240 55 28 8.6 4.7 | -44.8 -48.6 245 67 35 7.9 4.3
29000 -42.8 -45.0 240 54 28 8.5 4.7 | -42.5 -44.5 245 62 32 8.0 4.4
28000 -40.2 -40.4 245 53 27 8.5 4.7 | -40.1 -40.2 240 57 29 8.0 4.4
27000 -37.6 -35.7 245 52 27 8.0 4.4 | -37.7 -35.9 240 51 26 7.5 4.1
26000 -35.6 -32.1 240 49 25 6.9 3.8 | -35.6 -32.1 240 49 25 6.8 3.7
25000 -33.5 -28.3 240 47 24 6.9 3.8 | -33.6 -28.5 240 47 24 6.8 3.7
24000 -31.4 -24.5 240 44 23 6.8 3.7 | -31.6 -24.9 240 45 23 6.9 3.8
23000 -29.7 -21.5 235 41 21 5.6 3.1 | -29.4 -20.9 240 41 21 7.2 3.9
22000 -28.0 -18.4 230 38 20 5.6 3.1 | -27.3 -17.1 235 38 20 7.2 3.9
21000 -26.3 -15.3 225 36 18 6.7 3.7 | -25.2 -13.4 230 35 18 7.9 4.3
20000 -24.1 -11.4 225 34 18 7.6 4.2 | -22.7 -8.9 225 32 16 8.3 4.5
19500 -23.0 -9.4 230 33 17 7.6 4.2 | -21.5 -6.7 220 30 16 8.3 4.5
19000 -21.8 -7.2 230 33 17 7.6 4.2 | -20.3 -4.5 215 29 15 8.2 4.5
18500 -20.7 -5.3 230 32 16 7.7 4.2 | -19.0 -2.2 210 28 15 7.5 4.1
18000 -19.6 -3.3 230 32 16 7.7 4.3 | -18.1 -0.6 210 27 14 6.6 3.6
17500 -18.4 -1.1 235 31 16 7.7 4.2 | -17.1 1.2 215 26 13 6.6 3.6
17000 -17.2 1.0 235 31 16 8.5 4.6 | -16.2 2.8 215 25 13 6.2 3.4
16500 -16.0 3.2 235 30 16 8.4 4.6 | -15.2 4.6 220 24 12 6.2 3.4
16000 -14.8 5.4 235 30 15 7.5 4.1 | -14.3 6.3 220 23 12 6.4 3.5
15500 -13.8 7.2 230 27 14 7.1 3.9 | -13.4 7.9 220 21 11 6.4 3.5
15000 -12.7 9.1 230 25 13 5.1 2.8 | -12.4 9.7 220 20 10 5.0 2.7
14500 -12.3 9.9 220 21 11 2.1 1.1 | -11.9 10.6 215 19 10 3.1 1.7
14000 -12.0 10.4 205 18 9 2.1 1.2 | -11.0 12.2 200 17 9 6.5 3.6
13500 -10.5 13.1 190 16 8 8.1 4.4 | -10.1 13.8 190 15 8 6.8 3.8
13000 -9.2 15.4 180 16 8 8.5 4.7 | -9.3 15.3 180 13 7 6.1 3.3
12500 -7.9 17.8 170 16 8 8.8 4.8 | -8.1 17.4 165 12 6 8.0 4.4
12000 -6.8 19.8 160 15 8 5.1 2.8 | -7.0 19.4 145 12 6 5.8 3.2
11750 -6.5 20.3 150 15 8 3.0 1.6 | -6.6 20.1 135 12 6 7.4 4.0
11500 -6.3 20.7 140 14 7 3.6 2.0 | -5.9 21.4 125 11 6 9.1 5.0
11250 -6.0 21.2 130 14 7 3.9 2.1 | -5.3 22.5 115 11 6 8.7 4.8
11000 -5.7 21.7 120 13 7 6.1 3.3 | -4.6 23.7 105 11 6 8.8 4.8
10750 -5.1 22.8 110 13 7 8.5 4.6 | -4.0 24.8 100 11 6 9.3 5.1
10500 -4.4 24.1 105 13 6 9.7 5.3 | -3.2 26.2 100 11 6 10.1 5.5
10250 -3.7 25.3 100 12 6 9.8 5.4 | -2.5 27.5 095 11 6 10.2 5.6
10000 -3.0 26.6 095 12 6 9.4 5.1 | -1.7 28.9 095 11 6 10.2 5.6
9750 -2.3 27.9 095 12 6 9.5 5.2 | -0.9 30.4 095 11 6 10.6 5.8
9500 -1.5 29.3 095 11 6 10.4 5.7 | -0.1 31.8 090 11 6 11.6 6.4
9250 -0.6 30.9 090 11 6 14.9 8.2 | 0.9 33.6 090 10 5 18.6 10.2
9000 1.0 33.8 090 10 5 33.0 18.1 | 3.3 37.9 090 10 5 50.3 27.6
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
05/09/2024 at 1500 MDT | 05/09/2024 at 1800 MDT
|
CAPE... +56.9 LI... -0.5 | CAPE... +27.6 LI... -0.0
CINH... -1.1 K Index... +14.7 | CINH... 0.0 K Index... +18.2
|
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 -54.0 -65.2 265 13 7 2.0 1.1 | -54.2 -65.6 270 16 8 2.0 1.1
45000 -51.0 -59.8 255 23 12 0.1 0.1 | -51.3 -60.3 260 26 14 1.2 0.6
40000 -50.6 -59.1 245 31 16 0.2 0.1 | -49.4 -56.9 250 39 20 1.3 0.7
38000 -50.6 -59.1 245 42 21 -0.2 -0.1 | -49.4 -56.9 245 48 25 -0.9 -0.5
36000 -50.7 -59.3 245 60 31 -0.2 -0.1 | -50.0 -58.0 240 60 31 -0.9 -0.5
34000 -50.6 -59.1 245 75 39 4.7 2.6 | -50.0 -58.0 240 68 35 3.4 1.9
32000 -47.6 -53.7 240 65 33 4.3 2.4 | -48.1 -54.6 240 59 30 3.3 1.8
30000 -44.4 -47.9 235 57 29 8.3 4.6 | -45.5 -49.9 235 51 26 8.2 4.5
29000 -41.9 -43.4 235 53 27 8.4 4.6 | -43.1 -45.6 235 48 25 8.0 4.4
28000 -39.4 -38.9 235 50 26 8.4 4.6 | -40.7 -41.3 235 46 24 8.0 4.4
27000 -36.8 -34.2 235 46 24 7.2 4.0 | -38.3 -36.9 235 43 22 7.9 4.3
26000 -35.0 -31.0 235 43 22 6.2 3.4 | -35.5 -31.9 235 39 20 7.6 4.2
25000 -33.1 -27.6 235 40 20 6.2 3.4 | -33.2 -27.8 235 36 19 7.6 4.2
24000 -31.3 -24.3 240 36 19 6.6 3.6 | -30.9 -23.6 235 34 17 8.4 4.6
23000 -29.0 -20.2 235 33 17 7.8 4.3 | -28.3 -18.9 230 33 17 8.9 4.9
22000 -26.7 -16.1 235 30 15 7.8 4.3 | -25.6 -14.1 230 33 17 8.9 4.9
21000 -24.4 -11.9 230 27 14 7.1 3.9 | -23.1 -9.6 230 32 17 7.0 3.8
20000 -22.3 -8.1 220 28 15 6.9 3.8 | -21.0 -5.8 225 31 16 7.1 3.9
19500 -21.3 -6.3 215 29 15 6.9 3.8 | -20.0 -4.0 225 30 15 7.1 3.9
19000 -20.3 -4.5 215 31 16 6.9 3.8 | -18.9 -2.0 225 29 15 7.1 3.9
18500 -19.2 -2.6 210 32 17 7.7 4.2 | -17.9 -0.2 220 28 15 7.2 4.0
18000 -18.0 -0.4 210 34 17 8.3 4.5 | -16.8 1.8 220 27 14 7.2 4.0
17500 -16.8 1.8 210 36 18 8.3 4.6 | -15.7 3.7 215 26 14 7.4 4.0
17000 -15.6 3.9 210 35 18 7.8 4.3 | -14.6 5.7 210 25 13 7.7 4.2
16500 -14.5 5.9 210 34 17 8.0 4.4 | -13.5 7.7 205 23 12 7.9 4.3
16000 -13.4 7.9 210 32 17 6.9 3.8 | -12.5 9.5 200 21 11 6.8 3.7
15500 -12.4 9.7 205 29 15 6.7 3.7 | -11.5 11.3 195 19 10 6.9 3.8
15000 -11.0 12.2 200 24 12 6.4 3.5 | -10.5 13.1 185 17 9 6.1 3.3
14500 -10.0 14.0 195 19 10 5.9 3.3 | -9.7 14.5 180 16 8 5.8 3.2
14000 -9.3 15.3 180 15 8 5.3 2.9 | -8.9 16.0 175 15 8 5.0 2.7
13500 -8.5 16.7 165 14 7 5.9 3.2 | -8.1 17.4 160 16 8 5.1 2.8
13000 -7.7 18.1 145 13 7 5.3 2.9 | -7.0 19.4 140 16 8 4.7 2.6
12500 -6.9 19.6 135 13 7 5.5 3.0 | -6.4 20.5 125 15 8 4.5 2.5
12000 -6.1 21.0 120 14 7 3.8 2.1 | -5.8 21.6 110 15 8 4.0 2.2
11750 -5.9 21.4 115 13 7 4.7 2.6 | -5.5 22.1 105 15 7 5.5 3.0
11500 -5.5 22.1 105 13 7 5.7 3.1 | -5.0 23.0 100 14 7 6.2 3.4
11250 -5.1 22.8 100 13 7 5.7 3.1 | -4.6 23.7 090 14 7 6.0 3.3
11000 -4.6 23.7 095 13 7 6.6 3.6 | -4.2 24.4 090 14 7 6.0 3.3
10750 -4.1 24.6 090 13 7 7.8 4.3 | -3.7 25.3 085 14 7 6.3 3.4
10500 -3.5 25.7 085 12 6 8.6 4.7 | -3.3 26.1 085 14 7 6.5 3.6
10250 -2.9 26.8 080 12 6 9.3 5.1 | -2.8 27.0 080 13 7 7.3 4.0
10000 -2.1 28.2 075 11 6 10.3 5.7 | -2.2 28.0 080 13 6 8.4 4.6
9750 -1.4 29.5 075 11 6 11.0 6.0 | -1.6 29.1 075 12 6 8.5 4.7
9500 -0.5 31.1 070 10 5 10.4 5.7 | -1.0 30.2 075 11 6 9.1 5.0
9250 0.4 32.7 070 10 5 16.9 9.3 | -0.2 31.6 070 10 5 13.2 7.3
9000 3.0 37.4 070 9 5 64.0 35.1 | 1.3 34.3 070 7 4 30.2 16.6
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