293
UXUS97 KGJT 271306
SRGGJT
SOARING FORECAST
NATIONAL WEATHER SERVICE GRAND JUNCTION, COLORADO
706 AM MDT MONDAY, APRIL 27, 2026
THIS FORECAST IS FOR MONDAY, APRIL 27, 2026:
IF THE TRIGGER TEMPERATURE OF 49.1 F/9.5 C IS REACHED...THEN
THERMAL SOARING INDEX....................... EXCELLENT
MAXIMUM RATE OF LIFT........................ 903 FT/MIN (4.6 M/S)
MAXIMUM HEIGHT OF THERMALS.................. 20031 FT MSL (14424 FT AGL)
FORECAST MAXIMUM TEMPERATURE................... 64.0 F/18.2 C
TIME OF TRIGGER TEMPERATURE.................... 0915 MDT
TIME OF OVERDEVELOPMENT........................ 1100 MDT
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................. 15692 FT MSL (10085 FT AGL)
THERMAL SOARING OUTLOOK FOR TUESDAY 04/28...... EXCELLENT
WAVE SOARING INDEX............................. NOT AVAILABLE
REMARKS...
SUNRISE/SUNSET.................... 06:20:20 / 20:03:08 MDT
TOTAL POSSIBLE SUNSHINE........... 13 HR 42 MIN 48 SEC (822 MIN 48 SEC)
ALTITUDE OF SUN AT 13:11:44 MDT... 64.77 DEGREES
UPPER AIR DATA FROM RAWINSONDE OBSERVATION TAKEN ON 04/27/2026 AT 0600 MDT
FREEZING LEVEL.................. 8566 FT MSL (2959 FT AGL)
CONVECTIVE CONDENSATION LEVEL... 10534 FT MSL (4927 FT AGL)
LIFTED CONDENSATION LEVEL....... 13658 FT MSL (8051 FT AGL)
LIFTED INDEX.................... -3.8
K INDEX......................... +17.6
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 -54.4 -65.9 255 40 20 0.7 0.4 M M M M M
45000 -53.4 -64.1 260 47 24 0.6 0.3 M M M M M
40000 -53.9 -65.0 265 64 33 -0.3 -0.2 M M M M M
38000 -53.6 -64.5 265 70 36 1.7 1.0 M M M M M
36000 -52.4 -62.3 265 72 37 1.8 1.0 M M M M M
34000 -51.3 -60.3 265 73 38 4.3 2.3 M M M M M
32000 -48.4 -55.1 265 69 36 4.7 2.6 M M M M M
30000 -45.5 -49.9 265 65 33 6.7 3.7 30.2 86.3 9.3 M M
29000 -43.5 -46.3 270 62 32 6.9 3.8 28.9 84.0 8.5 M M
28000 -41.4 -42.5 270 60 31 6.9 3.8 27.8 82.0 7.7 M M
27000 -39.3 -38.7 270 57 29 7.0 3.8 26.8 80.2 7.0 M M
26000 -37.4 -35.3 270 53 27 5.9 3.2 25.4 77.7 6.0 M M
25000 -35.7 -32.3 270 48 24 5.9 3.2 23.9 75.0 4.9 M M
24000 -33.9 -29.0 270 42 22 5.9 3.2 22.5 72.6 3.8 M M
23000 -32.1 -25.8 265 38 20 6.3 3.4 21.2 70.1 2.8 M M
22000 -30.2 -22.4 265 35 18 6.3 3.5 19.9 67.8 1.7 M M
21000 -28.3 -18.9 265 31 16 6.4 3.5 18.7 65.7 0.8 M M
20000 -25.5 -13.9 260 30 15 7.9 4.3 17.7 63.9 -0.1 1289 6.5
19500 -24.3 -11.7 260 30 15 7.9 4.3 17.4 63.4 -0.4 1238 6.3
19000 -23.1 -9.6 260 29 15 7.9 4.3 17.1 62.8 -0.6 1188 6.0
18500 -22.0 -7.6 260 29 15 7.7 4.2 16.9 62.4 -0.9 1138 5.8
18000 -20.8 -5.4 260 29 15 7.5 4.1 16.5 61.6 -1.3 1090 5.5
17500 -19.7 -3.5 255 29 15 7.5 4.1 16.1 61.0 -1.6 1042 5.3
17000 -18.6 -1.5 255 29 15 7.3 4.0 15.7 60.2 -2.0 994 5.1
16500 -17.5 0.5 255 29 15 7.4 4.0 15.3 59.5 -2.4 947 4.8
16000 -16.5 2.3 255 29 15 7.2 4.0 14.9 58.8 -2.8 900 4.6
15500 -15.4 4.3 255 29 15 7.2 4.0 14.4 58.0 -3.2 853 4.3
15000 -14.3 6.3 255 29 15 7.1 3.9 14.0 57.2 -3.6 807 4.1
14500 -13.3 8.1 255 28 14 7.0 3.9 13.6 56.4 -4.1 761 3.9
14000 -12.3 9.9 255 27 14 7.1 3.9 13.1 55.6 -4.5 716 3.6
13500 -11.3 11.7 255 26 13 7.2 3.9 12.7 54.8 -5.0 670 3.4
13000 -10.2 13.6 255 25 13 7.4 4.0 12.3 54.1 -5.4 624 3.2
12500 -9.1 15.6 255 23 12 7.9 4.3 11.9 53.5 -5.8 575 2.9
12000 -7.9 17.8 255 22 11 7.9 4.3 11.6 52.9 -6.1 526 2.7
11500 -6.8 19.8 260 21 11 7.8 4.3 11.3 52.4 -6.5 477 2.4
11000 -5.6 21.9 260 19 10 7.6 4.1 11.0 51.8 -6.9 428 2.2
10500 -4.6 23.7 260 17 9 6.5 3.6 10.6 51.1 -7.3 382 1.9
10250 -4.1 24.6 260 16 8 9.0 5.0 10.4 50.7 -7.6 359 1.8
10000 -3.4 25.9 260 16 8 9.3 5.1 10.4 50.7 -7.6 330 1.7
9750 -2.8 27.0 260 15 8 7.1 3.9 10.3 50.5 -7.8 305 1.6
9500 -2.3 27.9 260 15 8 7.1 3.9 10.1 50.1 -8.0 282 1.4
9250 -1.8 28.8 260 14 7 8.0 4.4 9.9 49.8 -8.2 259 1.3
9000 -1.1 30.0 260 14 7 8.4 4.6 9.8 49.6 -8.4 233 1.2
8750 -0.6 30.9 260 14 7 7.7 4.2 9.6 49.3 -8.5 209 1.1
8500 0.0 32.0 260 13 7 7.9 4.4 9.5 49.1 -8.7 184 0.9
8250 0.6 33.1 260 13 7 7.8 4.3 9.3 48.8 -8.9 159 0.8
8000 1.2 34.2 260 13 7 7.8 4.3 9.2 48.5 -9.1 135 0.7
7750 1.7 35.1 260 12 6 7.8 4.3 9.0 48.3 -9.2 110 0.6
7500 2.3 36.1 260 11 6 7.9 4.3 8.9 48.0 -9.4 85 0.4
7250 2.9 37.2 260 10 5 7.3 4.0 8.7 47.7 -9.6 61 0.3
7000 3.4 38.1 260 10 5 6.8 3.7 8.5 47.3 -9.8 38 0.2
6750 3.9 39.0 260 8 4 7.1 3.9 8.3 47.0 -10.1 16 0.1
6500 4.4 39.9 260 7 4 6.6 3.6 8.1 46.6 -10.3 M M
6250 4.8 40.6 260 6 3 5.0 2.7 7.8 46.1 -10.7 M M
6000 5.2 41.4 255 5 3 5.6 3.1 7.4 45.4 -11.1 M M
5750 5.5 41.9 255 4 2 2.0 1.1 7.1 44.8 -11.5 M M
5500 M M M M M M M M M M M M
5250 M M M M M M M M M M M M
5000 M M M M M M M M M M M M
* * * * * * NUMERICAL WEATHER PREDICTION MODEL FORECAST DATA VALID * * * * * *
04/27/2026 AT 0900 MDT | 04/27/2026 AT 1200 MDT
|
CAPE... +55.8 LI... +0.4 | CAPE... +123.5 LI... -0.5
CINH... -5.3 K INDEX... +20.6 | CINH... -1.4 K INDEX... +23.6
|
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 -53.7 -64.7 240 46 24 1.3 0.7 | -53.1 -63.6 240 51 26 0.6 0.3
45000 -51.8 -61.2 250 53 27 1.4 0.8 | -52.1 -61.8 240 61 31 0.7 0.4
40000 -52.0 -61.6 250 62 32 -0.2 -0.1 | -52.7 -62.9 250 66 34 -0.5 -0.3
38000 -52.3 -62.1 250 63 32 -1.1 -0.6 | -53.0 -63.4 250 68 35 -0.5 -0.3
36000 -53.1 -63.6 250 56 29 -1.1 -0.6 | -53.3 -63.9 250 65 34 -0.5 -0.3
34000 -53.7 -64.7 250 50 26 2.0 1.1 | -53.6 -64.5 250 63 32 2.6 1.4
32000 -50.9 -59.6 250 45 23 4.7 2.6 | -50.8 -59.4 250 55 28 4.7 2.6
30000 -48.0 -54.4 250 39 20 6.3 3.5 | -47.9 -54.2 250 47 24 6.2 3.4
29000 -45.9 -50.6 250 38 19 7.2 3.9 | -45.9 -50.6 245 45 23 6.8 3.7
28000 -43.7 -46.7 250 36 19 7.2 3.9 | -43.9 -47.0 245 43 22 6.8 3.7
27000 -41.6 -42.9 245 35 18 7.1 3.9 | -41.9 -43.4 245 41 21 6.7 3.7
26000 -39.2 -38.6 245 34 18 8.4 4.6 | -39.5 -39.1 245 40 20 8.6 4.7
25000 -36.7 -34.1 250 33 17 8.4 4.6 | -36.9 -34.4 250 38 20 8.6 4.7
24000 -34.2 -29.6 250 33 17 8.4 4.6 | -34.4 -29.9 250 37 19 8.6 4.7
23000 -31.8 -25.2 250 32 16 7.9 4.3 | -31.8 -25.2 250 36 18 8.5 4.7
22000 -28.9 -20.0 250 30 16 7.9 4.3 | -29.3 -20.7 245 35 18 8.5 4.7
21000 -26.5 -15.7 250 29 15 7.5 4.1 | -26.2 -15.2 245 33 17 7.6 4.2
20000 -24.4 -11.9 245 27 14 7.1 3.9 | -24.1 -11.4 240 31 16 6.9 3.8
19500 -23.4 -10.1 245 25 13 7.1 3.9 | -23.1 -9.6 240 30 15 6.9 3.8
19000 -22.3 -8.1 245 24 12 7.1 3.9 | -22.1 -7.8 240 29 15 6.9 3.8
18500 -21.3 -6.3 245 23 12 7.0 3.9 | -21.0 -5.8 240 28 14 6.9 3.8
18000 -20.3 -4.5 245 22 11 6.8 3.8 | -20.1 -4.2 240 27 14 6.7 3.7
17500 -19.3 -2.7 240 21 11 6.9 3.8 | -19.1 -2.4 240 25 13 6.7 3.7
17000 -18.3 -0.9 240 20 10 6.9 3.8 | -18.1 -0.6 235 24 12 7.2 4.0
16500 -17.3 0.9 240 19 10 6.9 3.8 | -17.0 1.4 235 23 12 7.2 4.0
16000 -16.2 2.8 240 18 9 7.1 3.9 | -16.0 3.2 235 22 12 7.4 4.1
15500 -15.2 4.6 240 17 9 7.2 4.0 | -14.9 5.2 235 22 11 7.5 4.1
15000 -14.1 6.6 240 17 9 7.2 4.0 | -13.8 7.2 235 21 11 7.5 4.1
14500 -13.1 8.4 240 16 8 7.2 3.9 | -12.7 9.1 230 20 10 7.5 4.1
14000 -12.0 10.4 240 15 8 7.2 3.9 | -11.6 11.1 230 19 10 7.5 4.1
13500 -11.0 12.2 240 15 8 7.0 3.8 | -10.5 13.1 230 18 9 7.4 4.1
13000 -10.0 14.0 240 14 7 7.0 3.9 | -9.4 15.1 225 17 9 7.4 4.1
12500 -9.0 15.8 240 14 7 6.7 3.7 | -8.4 16.9 225 16 8 7.2 3.9
12000 -8.0 17.6 240 13 7 6.7 3.7 | -7.3 18.9 220 15 8 7.2 3.9
11500 -7.0 19.4 240 13 6 7.0 3.8 | -6.2 20.8 220 14 7 7.8 4.3
11000 -6.0 21.2 240 12 6 7.0 3.9 | -5.1 22.8 215 13 7 7.7 4.2
10500 -5.1 22.8 245 11 6 6.0 3.3 | -4.1 24.6 215 12 6 6.3 3.5
10250 -4.6 23.7 245 11 6 5.8 3.2 | -3.6 25.5 215 11 6 6.9 3.8
10000 -4.1 24.6 240 10 5 9.1 5.0 | -3.0 26.6 215 11 5 10.2 5.6
9750 -3.4 25.9 240 10 5 9.3 5.1 | -2.2 28.0 210 10 5 9.7 5.3
9500 -2.9 26.8 240 10 5 6.6 3.6 | -1.6 29.1 210 10 5 7.6 4.2
9250 -2.3 27.9 235 9 5 7.2 4.0 | -1.1 30.0 210 9 4 7.7 4.2
9000 -1.8 28.8 235 8 4 7.5 4.1 | -0.5 31.1 210 8 4 9.5 5.2
8750 -1.2 29.8 225 8 4 8.0 4.4 | 0.3 32.5 205 9 4 10.5 5.8
8500 -0.7 30.7 220 7 4 7.8 4.3 | 1.0 33.8 205 8 4 9.0 5.0
8250 0.5 32.9 215 7 3 7.6 4.2 | 1.7 35.1 205 8 4 9.6 5.3
8000 1.0 33.8 220 6 3 7.8 4.3 | 2.4 36.3 205 8 4 8.7 4.8
7750 1.6 34.9 215 6 3 8.2 4.5 | 3.8 38.8 205 6 3 10.7 5.9
7500 2.2 36.0 205 5 3 7.9 4.3 | 4.6 40.3 205 7 3 9.9 5.4
7250 2.8 37.0 200 5 2 6.3 3.5 | 5.2 41.4 205 6 3 8.0 4.4
7000 3.2 37.8 195 4 2 8.1 4.5 | 5.8 42.4 200 5 3 9.5 5.2
6750 4.0 39.2 190 4 2 10.3 5.7 | 6.7 44.1 205 6 3 11.9 6.5
6500 4.7 40.5 180 4 2 9.7 5.3 | 7.5 45.5 205 6 3 10.6 5.8
6250 5.4 41.7 170 4 2 10.3 5.6 | 8.3 46.9 200 5 3 10.7 5.8
6000 6.1 43.0 160 4 2 8.7 4.8 | 9.1 48.4 200 4 2 8.7 4.8
5750 6.8 44.2 170 3 2 10.4 5.7 | 9.7 49.5 205 5 3 12.1 6.6
5500 8.4 47.1 150 3 2 43.7 24.0 | 12.0 53.6 200 4 2 63.2 34.7
5250 M M M M M M M | M M M M M M M
5000 M M M M M M M | M M M M M M M
04/27/2026 AT 1500 MDT | 04/27/2026 AT 1800 MDT
|
CAPE... +277.1 LI... -1.6 | CAPE... +271.2 LI... -1.8
CINH... -1.1 K INDEX... +26.6 | CINH... -15.0 K INDEX... +25.0
|
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 52 27 0.7 0.4 | -53.5 -64.3 250 46 24 1.0 0.6
45000 -52.1 -61.8 245 66 34 0.8 0.4 | -52.0 -61.6 250 58 30 1.1 0.6
40000 -52.5 -62.5 245 67 34 -0.3 -0.2 | -52.7 -62.9 245 64 33 -0.5 -0.3
38000 -52.9 -63.2 245 67 35 -1.2 -0.6 | -53.2 -63.8 245 66 34 -1.0 -0.5
36000 -53.7 -64.7 245 67 35 -1.2 -0.7 | -53.7 -64.7 245 65 34 -1.0 -0.5
34000 -54.3 -65.7 250 67 35 2.4 1.3 | -54.2 -65.6 245 65 33 2.6 1.4
32000 -51.5 -60.7 250 62 32 4.7 2.6 | -51.4 -60.5 245 60 31 4.7 2.6
30000 -48.6 -55.5 250 56 29 7.0 3.8 | -48.5 -55.3 245 56 29 6.7 3.7
29000 -46.3 -51.3 245 53 27 7.5 4.1 | -46.3 -51.3 245 54 28 7.2 4.0
28000 -44.1 -47.4 245 50 26 7.5 4.1 | -44.1 -47.4 250 52 27 7.2 4.0
27000 -41.8 -43.2 245 47 24 7.4 4.1 | -42.0 -43.6 250 50 26 7.1 3.9
26000 -39.4 -38.9 245 45 23 8.5 4.7 | -39.5 -39.1 250 48 25 8.7 4.8
25000 -36.8 -34.2 240 43 22 8.5 4.7 | -36.9 -34.4 245 46 24 8.7 4.8
24000 -34.3 -29.7 240 40 21 8.5 4.7 | -34.3 -29.7 245 43 22 8.7 4.8
23000 -31.8 -25.2 240 39 20 8.2 4.5 | -31.2 -24.2 240 40 21 8.3 4.6
22000 -28.7 -19.7 235 37 19 8.2 4.5 | -28.7 -19.7 240 38 19 8.3 4.6
21000 -26.3 -15.3 235 36 19 7.8 4.3 | -26.2 -15.2 235 35 18 7.7 4.2
20000 -24.1 -11.4 235 34 17 7.6 4.2 | -24.1 -11.4 235 34 17 7.3 4.0
19500 -23.0 -9.4 235 33 17 7.6 4.2 | -23.0 -9.4 230 33 17 7.4 4.0
19000 -21.8 -7.2 235 31 16 7.6 4.2 | -21.9 -7.4 230 32 17 7.4 4.1
18500 -20.7 -5.3 235 30 16 7.7 4.2 | -20.8 -5.4 230 32 16 7.8 4.3
18000 -19.6 -3.3 235 29 15 7.9 4.3 | -19.6 -3.3 230 31 16 8.2 4.5
17500 -18.4 -1.1 235 28 14 7.9 4.3 | -18.4 -1.1 230 30 16 8.2 4.5
17000 -17.2 1.0 230 27 14 8.4 4.6 | -17.2 1.0 230 30 15 8.3 4.6
16500 -16.0 3.2 230 26 13 8.3 4.6 | -16.0 3.2 230 29 15 8.3 4.6
16000 -14.8 5.4 230 25 13 8.2 4.5 | -14.8 5.4 230 29 15 8.5 4.7
15500 -13.6 7.5 230 24 12 8.2 4.5 | -13.5 7.7 230 28 14 8.6 4.7
15000 -12.4 9.7 225 23 12 8.0 4.4 | -12.3 9.9 230 27 14 8.6 4.7
14500 -11.3 11.7 225 23 12 7.7 4.2 | -11.0 12.2 230 27 14 8.5 4.7
14000 -10.1 13.8 225 22 11 7.7 4.2 | -9.8 14.4 230 27 14 8.5 4.7
13500 -9.0 15.8 225 21 11 7.7 4.2 | -8.5 16.7 230 26 14 8.5 4.7
13000 -7.9 17.8 225 20 10 7.7 4.2 | -7.3 18.9 230 26 13 8.6 4.7
12500 -6.8 19.8 225 19 10 7.5 4.1 | -6.0 21.2 225 25 13 9.0 5.0
12000 -5.7 21.7 225 18 9 7.6 4.1 | -4.6 23.7 225 25 13 9.0 5.0
11500 -4.6 23.7 225 17 9 7.6 4.2 | -3.3 26.1 225 25 13 9.4 5.2
11000 -3.5 25.7 225 16 8 7.6 4.1 | -1.9 28.6 225 24 12 9.4 5.1
10500 -2.4 27.7 225 14 7 7.0 3.9 | -0.6 30.9 225 23 12 7.9 4.3
10250 -1.9 28.6 225 13 7 7.7 4.2 | 0.0 32.0 225 22 11 8.9 4.9
10000 -1.2 29.8 225 13 7 9.8 5.4 | 0.8 33.4 225 22 11 10.7 5.9
9750 -0.5 31.1 225 13 7 9.7 5.3 | 1.6 34.9 225 22 11 10.0 5.5
9500 0.2 32.4 225 13 7 8.7 4.8 | 2.3 36.1 225 21 11 9.1 5.0
9250 0.8 33.4 225 12 6 9.0 4.9 | 2.9 37.2 225 21 11 9.4 5.1
9000 1.5 34.7 225 12 6 8.9 4.9 | 3.6 38.5 220 20 10 9.3 5.1
8750 2.2 36.0 225 12 6 9.4 5.2 | 5.0 41.0 220 20 10 9.3 5.1
8500 2.9 37.2 225 12 6 9.8 5.4 | 5.7 42.3 220 19 10 9.4 5.2
8250 4.3 39.7 225 12 6 9.9 5.5 | 6.4 43.5 220 18 9 8.9 4.9
8000 5.1 41.2 225 11 6 9.8 5.4 | 7.0 44.6 215 17 9 8.6 4.7
7750 5.8 42.4 225 11 6 9.6 5.3 | 7.7 45.9 215 16 8 8.9 4.9
7500 6.5 43.7 225 11 6 9.5 5.2 | 8.3 46.9 215 16 8 8.7 4.8
7250 7.2 45.0 220 10 5 8.9 4.9 | 8.9 48.0 215 15 8 7.4 4.1
7000 7.9 46.2 225 10 5 9.8 5.4 | 9.5 49.1 210 14 7 8.1 4.5
6750 8.7 47.7 220 10 5 10.6 5.8 | 10.2 50.4 210 13 7 9.4 5.2
6500 9.4 48.9 220 10 5 10.7 5.9 | 10.8 51.4 210 12 6 9.6 5.3
6250 10.3 50.5 220 9 5 12.3 6.8 | 11.6 52.9 210 12 6 11.3 6.2
6000 11.1 52.0 220 9 4 8.7 4.8 | 12.4 54.3 205 12 6 8.9 4.9
5750 11.7 53.1 220 9 4 10.3 5.7 | 13.0 55.4 210 11 6 8.8 4.8
5500 14.2 57.6 220 7 4 73.4 40.3 | 14.6 58.3 205 9 5 45.2 24.8
5250 M M M M M M M | M M M M M M M
5000 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) AND AGAIN BY APPROXIMATELY 1830 MST/1930 MDT (0130 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 AT WALKER FIELD IN GRAND
JUNCTION, COLORADO AT
NORTH LATITUDE: 39 DEG 07 MIN 00.001 SEC
WEST LONGITUDE: 108 DEG 31 MIN 59.998 SEC
ELEVATION: 4839 FEET (1475 METERS)
AND MAY NOT BE REPRESENTATIVE OF OTHER AREAS ALONG THE WESTERN SLOPE OF
COLORADO. 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.
CINH (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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