706
UXUS97 KPUB 221207
SRGPUB
SOARING FORECAST
NATIONAL WEATHER SERVICE PUEBLO, COLORADO
0607 MDT SATURDAY, MARCH 22, 2025
THIS FORECAST IS FOR VILLA GROVE, CO FOR SATURDAY, MARCH 22, 2025:
IF THE TRIGGER TEMPERATURE OF 39.7 F/4.3 C IS REACHED...THEN
THERMAL SOARING INDEX....................... GOOD
MAXIMUM RATE OF LIFT........................ 1422 FT/MIN (7.2 M/S)
MAXIMUM HEIGHT OF THERMALS.................. 23466 FT MSL (14494 FT AGL)
FORECAST MAXIMUM TEMPERATURE................... 54.0 F/12.7 C
TIME OF TRIGGER TEMPERATURE.................... 0945 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................. 17743 FT MSL (8771 FT AGL)
THERMAL SOARING OUTLOOK FOR SUNDAY 03/23....... EXCELLENT
WAVE SOARING INDEX............................. NOT AVAILABLE
REMARKS...
SUNRISE/SUNSET.................... 07:02:59 / 19:17:31 MDT
TOTAL POSSIBLE SUNSHINE........... 12 HR 14 MIN 32 SEC (734 MIN 32 SEC)
ALTITUDE OF SUN AT 13:10:15 MDT... 52.62 DEGREES
UPPER AIR DATA FROM NUMERICAL MODEL FORECAST VALID ON 03/22/2025 AT 0600 MDT
FREEZING LEVEL.................. ENTIRE AIRMASS BELOW 32 F / 0 C
CONVECTIVE CONDENSATION LEVEL... 15696 FT MSL (6724 FT AGL)
LIFTED CONDENSATION LEVEL....... 17945 FT MSL (8973 FT AGL)
LIFTED INDEX.................... -4.1
K INDEX......................... +12.9
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 -58.1 -72.6 270 38 19 1.9 1.1 M M M M M
45000 -55.3 -67.5 270 48 25 1.8 1.0 M M M M M
40000 -57.0 -70.6 270 62 32 -1.5 -0.8 M M M M M
38000 -57.5 -71.5 270 67 34 0.6 0.3 M M M M M
36000 -57.1 -70.8 265 71 37 0.7 0.4 M M M M M
34000 -56.7 -70.1 260 76 39 2.7 1.5 M M M M M
32000 -52.9 -63.2 260 71 36 6.4 3.5 M M M M M
30000 -49.1 -56.4 265 66 34 7.4 4.1 15.1 59.2 2.3 M M
29000 -46.1 -51.0 270 61 31 8.0 4.4 14.1 57.4 1.5 M M
28000 -43.7 -46.7 270 58 30 8.0 4.4 13.4 56.2 1.0 M M
27000 -41.3 -42.3 275 54 28 8.1 4.5 12.9 55.2 0.5 M M
26000 -38.6 -37.5 275 52 27 9.4 5.2 12.6 54.7 0.3 M M
25000 -35.8 -32.4 270 51 26 9.4 5.2 12.5 54.5 0.2 M M
24000 -33.0 -27.4 270 49 25 9.5 5.2 12.4 54.4 0.1 M M
23000 -30.4 -22.7 275 50 26 8.3 4.6 12.0 53.6 -0.3 1371 7.0
22000 -27.9 -18.2 275 52 27 8.4 4.6 11.5 52.7 -0.7 1267 6.4
21000 -25.4 -13.7 275 54 28 8.3 4.6 11.1 52.0 -1.1 1163 5.9
20000 -23.0 -9.4 275 52 27 8.3 4.6 10.5 51.0 -1.6 1059 5.4
19500 -21.7 -7.1 275 51 26 8.3 4.6 10.3 50.5 -1.8 1007 5.1
19000 -20.5 -4.9 275 50 26 8.3 4.6 10.1 50.1 -2.1 955 4.9
18500 -19.3 -2.7 275 50 26 8.1 4.4 9.9 49.8 -2.3 903 4.6
18000 -18.2 -0.8 275 49 25 6.5 3.6 9.4 49.0 -2.7 857 4.4
17500 -17.2 1.0 280 47 24 6.6 3.6 8.9 48.1 -3.2 813 4.1
17000 -16.2 2.8 280 46 24 6.6 3.6 8.4 47.2 -3.7 769 3.9
16500 -15.3 4.5 280 46 23 6.6 3.6 7.9 46.2 -4.2 725 3.7
16000 -14.3 6.3 280 45 23 6.7 3.7 7.4 45.4 -4.7 680 3.5
15500 -13.3 8.1 280 44 23 6.9 3.8 6.9 44.5 -5.1 635 3.2
15000 -12.3 9.9 275 43 22 7.1 3.9 6.5 43.7 -5.6 590 3.0
14500 -10.5 13.1 275 41 21 7.7 4.2 6.1 43.0 -6.1 514 2.6
14000 -9.7 14.5 270 41 21 5.5 3.0 5.3 41.6 -6.8 478 2.4
13500 -8.6 16.5 270 41 21 7.7 4.2 5.0 41.0 -7.2 430 2.2
13000 -7.6 18.3 270 41 21 6.4 3.5 4.6 40.3 -7.7 383 1.9
12500 -6.6 20.1 265 37 19 6.5 3.6 4.1 39.4 -8.2 341 1.7
12000 -5.7 21.7 265 33 17 6.1 3.3 3.6 38.5 -8.8 298 1.5
11750 -5.3 22.5 265 34 17 5.8 3.2 3.3 37.9 -9.1 277 1.4
11500 -4.8 23.4 265 34 18 6.1 3.3 3.0 37.4 -9.4 257 1.3
11250 -4.4 24.1 265 35 18 6.0 3.3 2.7 36.9 -9.8 236 1.2
11000 -3.9 25.0 265 35 18 6.0 3.3 2.4 36.3 -10.0 215 1.1
10750 -3.5 25.7 265 33 17 4.6 2.5 2.1 35.8 -10.4 195 1.0
10500 -3.2 26.2 260 32 16 2.9 1.6 1.6 34.9 -10.9 179 0.9
10250 -3.0 26.6 260 30 15 4.0 2.2 1.1 34.0 -11.4 165 0.8
10000 -2.7 27.1 260 28 14 -0.1 -0.1 0.6 33.1 -11.9 150 0.8
9750 -3.0 26.6 255 25 13 -5.2 -2.8 -0.4 31.3 -12.9 151 0.8
9500 -3.3 26.1 250 22 11 -2.1 -1.1 -1.4 29.5 -14.0 152 0.8
9250 -3.4 25.9 240 18 9 -3.6 -2.0 -2.3 27.9 -14.9 148 0.8
9000 -4.5 23.9 230 10 5 -30.8 -16.9 -4.1 24.7 -16.7 172 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 * * * * * *
03/22/2025 AT 0900 MDT | 03/22/2025 AT 1200 MDT
|
CAPE... 0.0 LI... +0.4 | CAPE... +34.5 LI... +0.9
CINH... 0.0 K INDEX... +17.2 | CINH... -1.4 K INDEX... +6.0
|
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 -57.9 -72.2 270 40 21 0.7 0.4 | -58.2 -72.8 265 44 23 0.8 0.4
45000 -56.9 -70.4 270 50 26 0.6 0.4 | -57.0 -70.6 265 50 26 0.7 0.4
40000 -57.8 -72.0 275 65 34 -0.8 -0.4 | -58.2 -72.8 275 63 33 -0.9 -0.5
38000 -57.8 -72.0 275 68 35 1.7 0.9 | -58.3 -72.9 280 68 35 1.7 0.9
36000 -56.8 -70.2 280 65 33 1.7 0.9 | -57.3 -71.1 295 76 39 1.7 0.9
34000 -55.8 -68.4 290 62 32 3.3 1.8 | -56.2 -69.2 305 88 45 4.2 2.3
32000 -52.4 -62.3 285 60 31 5.7 3.1 | -52.4 -62.3 305 82 42 6.4 3.5
30000 -48.9 -56.0 285 58 30 7.2 3.9 | -47.8 -54.0 300 76 39 8.9 4.9
29000 -46.5 -51.7 285 58 30 8.0 4.4 | -45.2 -49.4 300 72 37 8.7 4.8
28000 -43.5 -46.3 285 58 30 8.0 4.4 | -42.5 -44.5 300 68 35 8.7 4.8
27000 -41.1 -42.0 285 57 29 8.0 4.4 | -39.9 -39.8 295 64 33 8.7 4.8
26000 -38.7 -37.7 285 53 27 8.3 4.5 | -37.3 -35.1 295 61 32 8.7 4.8
25000 -36.2 -33.2 285 47 24 8.3 4.5 | -34.7 -30.5 290 59 30 8.7 4.8
24000 -33.7 -28.7 285 42 21 8.2 4.5 | -32.1 -25.8 285 57 29 8.7 4.8
23000 -31.1 -24.0 280 41 21 8.9 4.9 | -29.4 -20.9 285 57 30 9.4 5.1
22000 -28.5 -19.3 280 42 22 8.9 4.9 | -26.6 -15.9 285 59 30 9.4 5.1
21000 -25.9 -14.6 280 43 22 8.6 4.7 | -23.8 -10.8 280 61 31 8.0 4.4
20000 -23.4 -10.1 280 43 22 8.2 4.5 | -21.9 -7.4 280 58 30 6.3 3.4
19500 -22.2 -8.0 280 44 22 8.2 4.5 | -21.0 -5.8 285 57 29 6.3 3.4
19000 -21.0 -5.8 280 44 23 8.2 4.5 | -20.0 -4.0 285 55 29 6.3 3.4
18500 -19.8 -3.6 280 44 23 8.1 4.5 | -19.1 -2.4 285 54 28 6.0 3.3
18000 -18.6 -1.5 275 45 23 7.8 4.3 | -18.3 -0.9 285 53 27 5.1 2.8
17500 -17.5 0.5 275 46 24 7.9 4.3 | -17.6 0.3 285 52 27 5.0 2.7
17000 -16.3 2.7 275 46 24 7.4 4.1 | -16.7 1.9 285 51 26 6.8 3.7
16500 -15.3 4.5 275 47 24 7.4 4.0 | -15.7 3.7 280 50 26 7.0 3.8
16000 -14.2 6.4 275 48 25 7.2 3.9 | -14.7 5.5 280 50 26 7.8 4.3
15500 -13.2 8.2 275 48 25 6.9 3.8 | -13.4 7.9 280 43 22 8.6 4.7
15000 -12.2 10.0 275 48 25 7.1 3.9 | -11.5 11.3 280 35 18 9.7 5.3
14500 -10.5 13.1 275 48 25 7.1 3.9 | -10.0 14.0 280 35 18 8.6 4.7
14000 -9.8 14.4 270 48 25 5.5 3.0 | -9.2 15.4 280 37 19 5.9 3.2
13500 -8.8 16.2 270 46 24 6.8 3.7 | -8.1 17.4 280 39 20 7.3 4.0
13000 -7.8 18.0 265 45 23 6.2 3.4 | -7.2 19.0 280 41 21 5.5 3.0
12500 -6.9 19.6 265 43 22 6.0 3.3 | -6.3 20.7 280 40 21 6.5 3.6
12000 -6.1 21.0 265 41 21 5.8 3.2 | -5.4 22.3 275 40 20 7.7 4.2
11750 -5.6 21.9 265 39 20 6.1 3.4 | -4.8 23.4 275 38 19 9.4 5.2
11500 -5.2 22.6 260 37 19 6.4 3.5 | -4.1 24.6 275 36 18 9.1 5.0
11250 -4.7 23.5 260 35 18 6.9 3.8 | -3.4 25.9 275 34 18 9.1 5.0
11000 -4.2 24.4 260 34 17 4.6 2.5 | -2.7 27.1 270 32 17 9.4 5.2
10750 -4.0 24.8 260 32 17 1.9 1.0 | -2.0 28.4 270 31 16 10.2 5.6
10500 -3.9 25.0 255 30 16 2.0 1.1 | -1.2 29.8 270 31 16 10.6 5.8
10250 -3.7 25.3 255 28 14 2.6 1.4 | -0.5 31.1 270 30 15 10.3 5.6
10000 -3.6 25.5 255 26 13 0.1 0.1 | 0.3 32.5 270 29 15 11.3 6.2
9750 -3.7 25.3 250 24 12 -2.1 -1.2 | 1.2 34.2 270 27 14 12.9 7.1
9500 -3.8 25.2 245 21 11 0.1 0.1 | 2.2 36.0 270 26 13 11.0 6.0
9250 -3.6 25.5 240 17 9 5.4 3.0 | 3.1 37.6 270 24 12 17.7 9.7
9000 -2.5 27.5 235 11 6 28.1 15.4 | 6.1 43.0 270 19 10 75.3 41.3
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
03/22/2025 AT 1500 MDT | 03/22/2025 AT 1800 MDT
|
CAPE... +35.3 LI... +1.1 | CAPE... 0.0 LI... +2.6
CINH... 0.0 K INDEX... +6.1 | CINH... 0.0 K INDEX... +3.1
|
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 -59.0 -74.2 275 48 24 -0.4 -0.2 | -58.6 -73.5 285 45 23 -0.8 -0.4
45000 -59.6 -75.3 280 51 26 -0.4 -0.2 | -59.8 -75.6 280 50 26 -0.8 -0.4
40000 -60.3 -76.5 290 57 29 -0.4 -0.2 | -62.4 -80.3 290 59 31 -1.8 -1.0
38000 -59.9 -75.8 290 64 33 2.4 1.3 | -61.8 -79.2 290 64 33 5.1 2.8
36000 -58.4 -73.1 290 77 40 2.3 1.3 | -58.7 -73.7 285 71 37 5.1 2.8
34000 -56.7 -70.1 290 89 46 8.4 4.6 | -55.4 -67.7 280 78 40 8.4 4.6
32000 -51.3 -60.3 285 87 45 9.1 5.0 | -50.5 -58.9 280 74 38 8.2 4.5
30000 -45.9 -50.6 285 84 43 8.3 4.5 | -45.5 -49.9 280 72 37 9.4 5.2
29000 -43.4 -46.1 285 80 41 8.2 4.5 | -42.7 -44.9 280 73 37 9.3 5.1
28000 -40.4 -40.7 290 75 39 8.2 4.5 | -39.3 -38.7 280 73 38 9.3 5.1
27000 -37.9 -36.2 290 71 37 8.2 4.5 | -36.5 -33.7 285 74 38 8.5 4.7
26000 -35.5 -31.9 290 69 36 8.1 4.5 | -34.1 -29.4 285 69 36 7.9 4.3
25000 -33.0 -27.4 290 67 34 8.1 4.5 | -31.8 -25.2 285 65 33 7.9 4.3
24000 -30.6 -23.1 290 64 33 8.3 4.6 | -29.4 -20.9 285 60 31 7.9 4.3
23000 -27.9 -18.2 290 61 31 9.1 5.0 | -27.1 -16.8 285 57 29 7.7 4.2
22000 -25.2 -13.4 285 57 30 9.1 5.0 | -24.8 -12.6 290 54 28 7.7 4.2
21000 -22.5 -8.5 285 54 28 7.6 4.2 | -22.5 -8.5 290 51 26 8.1 4.4
20000 -20.6 -5.1 285 52 27 6.4 3.5 | -20.0 -4.0 285 47 24 8.3 4.5
19500 -19.7 -3.5 285 51 26 6.4 3.5 | -18.8 -1.8 285 45 23 8.3 4.5
19000 -18.7 -1.7 285 50 26 6.4 3.5 | -17.6 0.3 280 42 22 8.3 4.5
18500 -17.8 -0.0 285 49 25 6.3 3.5 | -16.3 2.7 280 40 21 7.9 4.3
18000 -16.9 1.6 285 50 26 6.0 3.3 | -15.2 4.6 280 43 22 7.2 4.0
17500 -16.0 3.2 285 51 26 6.1 3.4 | -14.2 6.4 280 45 23 7.4 4.1
17000 -15.2 4.6 285 51 26 5.0 2.8 | -13.2 8.2 285 47 24 5.1 2.8
16500 -14.4 6.1 280 51 26 5.1 2.8 | -12.5 9.5 285 49 25 5.1 2.8
16000 -13.7 7.3 280 51 26 6.1 3.3 | -11.7 10.9 285 50 26 4.9 2.7
15500 -12.7 9.1 275 49 25 6.9 3.8 | -11.0 12.2 285 50 25 4.7 2.6
15000 -11.7 10.9 275 48 25 7.6 4.1 | -10.3 13.5 285 49 25 5.0 2.7
14500 -9.6 14.7 270 49 25 8.0 4.4 | -9.5 14.9 285 48 25 6.8 3.7
14000 -8.8 16.2 270 47 24 7.0 3.8 | -8.5 16.7 285 47 24 5.0 2.7
13500 -7.6 18.3 265 44 23 8.7 4.8 | -7.5 18.5 280 49 25 6.6 3.6
13000 -6.4 20.5 265 43 22 7.0 3.8 | -6.6 20.1 280 50 26 6.4 3.5
12500 -5.4 22.3 270 41 21 7.5 4.1 | -5.6 21.9 280 50 26 7.2 4.0
12000 -4.3 24.3 270 39 20 8.6 4.7 | -4.5 23.9 275 50 26 6.7 3.7
11750 -3.6 25.5 270 38 19 10.4 5.7 | -4.1 24.6 275 47 24 7.3 4.0
11500 -2.8 27.0 270 36 19 10.0 5.5 | -3.5 25.7 275 45 23 8.4 4.6
11250 -2.1 28.2 270 35 18 10.5 5.7 | -2.9 26.8 275 43 22 8.2 4.5
11000 -1.4 29.5 270 34 17 9.0 5.0 | -2.3 27.9 275 41 21 8.0 4.4
10750 -0.7 30.7 270 33 17 9.2 5.0 | -1.7 28.9 270 39 20 9.2 5.1
10500 0.1 32.2 270 32 17 11.0 6.1 | -0.9 30.4 270 37 19 10.7 5.9
10250 0.9 33.6 270 32 16 10.5 5.7 | -0.2 31.6 270 35 18 10.6 5.8
10000 1.7 35.1 270 31 16 11.7 6.4 | 0.6 33.1 270 33 17 10.3 5.7
9750 2.6 36.7 270 30 15 13.3 7.3 | 1.4 34.5 270 31 16 10.2 5.6
9500 3.5 38.3 270 28 14 9.4 5.2 | 2.1 35.8 270 29 15 9.6 5.3
9250 4.2 39.6 275 25 13 14.7 8.1 | 2.9 37.2 270 25 13 12.1 6.6
9000 7.3 45.1 275 20 10 84.4 46.3 | 4.4 39.9 270 18 9 35.6 19.5
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.
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