322  
UXUS97 KGJT 211254  
SRGGJT  
 
SOARING FORECAST  
NATIONAL WEATHER SERVICE GRAND JUNCTION, COLORADO  
0554 MST WEDNESDAY, FEBRUARY 21, 2018  
 
THIS FORECAST IS FOR WEDNESDAY, FEBRUARY 21, 2018:  
 
IF THE TRIGGER TEMPERATURE OF 31.7 F/-0.1 C IS REACHED...THEN  
THERMAL SOARING INDEX....................... GOOD  
MAXIMUM RATE OF LIFT........................ 732 FT/MIN (3.7 M/S)  
MAXIMUM HEIGHT OF THERMALS.................. 14270 FT MSL (9431 FT AGL)  
 
FORECAST MAXIMUM TEMPERATURE................... 37.0 F/3.2 C  
TIME OF TRIGGER TEMPERATURE.................... 1100 MST  
TIME OF OVERDEVELOPMENT........................ NONE  
MIDDLE/HIGH CLOUDS DURING SOARING WINDOW....... OVERCAST THIN HIGH  
SURFACE WINDS DURING SOARING WINDOW............ 20 MPH OR LESS  
HEIGHT OF THE -3 THERMAL INDEX................. 8565 FT MSL (3725 FT AGL)  
THERMAL SOARING OUTLOOK FOR THURSDAY 02/22..... GOOD  
 
WAVE SOARING INDEX............................. NOT AVAILABLE  
 
REMARKS...  
 
SUNRISE/SUNSET.................... 06:57:38 / 17:56:59 MST  
TOTAL POSSIBLE SUNSHINE........... 10 HR 59 MIN 21 SEC (659 MIN 21 SEC)  
ALTITUDE OF SUN AT 12:27:35 MST... 40.55 DEGREES  
 
UPPER AIR DATA FROM RAWINSONDE OBSERVATION TAKEN ON 02/21/2018 AT 0500 MST  
 
FREEZING LEVEL.................. ENTIRE AIRMASS BELOW 32 F / 0 C  
CONVECTIVE CONDENSATION LEVEL... 10914 FT MSL (6075 FT AGL)  
LIFTED CONDENSATION LEVEL....... 12069 FT MSL (7230 FT AGL)  
LIFTED INDEX.................... +10.5  
K INDEX......................... -19.7  
 
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 -58.0 -72.4 225 89 46 -3.3 -1.8 110.5 230.9 60.4 M M  
45000 -52.9 -63.2 220 78 40 3.4 1.8 92.7 198.9 54.1 M M  
40000 -52.9 -63.2 215 84 43 2.0 1.1 69.4 156.8 42.8 M M  
38000 -52.2 -62.0 230 74 38 8.0 4.4 61.5 142.7 38.8 M M  
36000 -56.0 -68.8 235 84 43 3.0 1.7 47.1 116.8 30.1 M M  
34000 -55.8 -68.4 230 75 39 4.6 2.5 38.8 101.9 25.1 M M  
32000 -55.2 -67.4 215 80 41 0.5 0.3 30.5 86.9 19.9 M M  
30000 -52.0 -61.6 215 75 38 6.6 3.6 26.9 80.3 17.8 M M  
29000 -49.9 -57.8 215 72 37 7.1 3.9 25.6 78.1 17.0 M M  
28000 -47.8 -54.0 215 69 35 7.1 3.9 24.5 76.1 16.4 M M  
27000 -45.7 -50.3 220 66 34 7.5 4.1 23.5 74.4 15.9 M M  
26000 -43.3 -45.9 220 64 33 8.0 4.4 22.8 73.0 15.5 M M  
25000 -40.9 -41.6 220 61 31 8.0 4.4 22.2 71.9 15.3 M M  
24000 -38.7 -37.7 220 59 30 4.4 2.4 21.2 70.1 14.6 M M  
23000 -37.3 -35.1 220 56 29 5.1 2.8 19.3 66.8 13.3 M M  
22000 -35.5 -31.9 220 49 25 8.6 4.7 17.9 64.3 12.4 M M  
21000 -33.0 -27.4 220 51 26 8.3 4.6 17.4 63.3 12.1 M M  
20000 -30.5 -22.9 225 53 27 8.3 4.6 16.9 62.5 11.8 M M  
19500 -29.3 -20.7 225 55 28 8.3 4.6 16.7 62.0 11.7 M M  
19000 -28.0 -18.4 225 58 30 8.3 4.6 16.4 61.6 11.6 M M  
18500 -26.9 -16.4 230 51 26 4.9 2.7 16.1 60.9 11.3 M M  
18000 -26.4 -15.5 235 43 22 2.3 1.3 14.9 58.8 10.4 M M  
17500 -26.7 -16.1 235 41 21 -0.3 -0.2 12.9 55.2 8.7 M M  
17000 -25.7 -14.3 240 41 21 4.9 2.7 11.4 52.6 7.5 M M  
16500 -25.4 -13.7 235 38 20 -1.5 -0.8 10.1 50.3 6.4 M M  
16000 -25.7 -14.3 235 35 18 -3.6 -2.0 8.1 46.7 4.7 M M  
15500 -26.2 -15.2 235 33 17 0.6 0.3 5.9 42.6 2.7 M M  
15000 -25.9 -14.6 230 30 15 2.4 1.3 4.6 40.4 1.7 M M  
14500 -25.6 -14.1 230 27 14 0.7 0.4 3.3 37.9 0.4 M M  
14000 -25.5 -13.9 225 24 13 2.1 1.2 1.8 35.2 -0.9 820 4.2  
13500 -24.6 -12.3 220 20 10 8.4 4.6 1.2 34.2 -1.5 778 4.0  
13000 -23.4 -10.1 215 16 8 8.1 4.4 0.9 33.7 -1.7 727 3.7  
12500 -22.2 -8.0 215 16 8 8.2 4.5 0.6 33.2 -2.0 676 3.4  
12000 -21.1 -6.0 215 16 8 8.0 4.4 0.3 32.5 -2.4 629 3.2  
11500 -19.7 -3.5 215 16 8 9.9 5.4 0.2 32.4 -2.5 571 2.9  
11000 -18.4 -1.1 215 16 8 8.6 4.7 0.1 32.2 -2.6 517 2.6  
10500 -17.0 1.4 220 16 8 9.6 5.3 0.1 32.1 -2.7 460 2.3  
10250 -16.3 2.7 220 16 8 9.4 5.2 0.1 32.1 -2.7 431 2.2  
10000 -15.6 3.9 220 16 8 9.5 5.2 0.0 32.0 -2.8 403 2.0  
9750 -14.9 5.2 220 16 8 10.0 5.5 0.0 32.0 -2.8 374 1.9  
9500 -14.1 6.6 220 16 8 10.0 5.5 0.0 32.1 -2.8 344 1.7  
9250 -13.3 8.1 215 15 8 10.2 5.6 0.1 32.1 -2.7 314 1.6  
9000 -12.6 9.3 215 15 8 9.4 5.1 0.1 32.2 -2.7 284 1.4  
8750 -12.0 10.4 210 15 8 7.7 4.2 -0.0 32.0 -2.8 258 1.3  
8500 -11.4 11.5 205 14 7 7.3 4.0 -0.2 31.6 -3.0 235 1.2  
8250 -10.9 12.4 200 14 7 7.5 4.1 -0.4 31.3 -3.2 211 1.1  
8000 -10.3 13.5 195 14 7 7.2 4.0 -0.6 31.0 -3.4 187 1.0  
7750 -9.8 14.4 185 15 7 8.0 4.4 -0.7 30.7 -3.6 164 0.8  
7500 -9.2 15.4 175 16 8 8.5 4.7 -0.8 30.5 -3.7 137 0.7  
7250 -8.5 16.7 170 17 9 10.1 5.6 -0.9 30.4 -3.8 110 0.6  
7000 -7.9 17.8 160 19 10 4.1 2.3 -1.0 30.3 -3.9 83 0.4  
6750 -8.0 17.6 160 19 10 -5.2 -2.9 -1.8 28.7 -4.8 80 0.4  
6500 -8.3 17.1 160 18 9 0.7 0.4 -2.9 26.8 -5.8 82 0.4  
6250 -7.9 17.8 155 18 9 5.9 3.3 -3.2 26.2 -6.2 63 0.3  
6000 -7.6 18.3 155 17 9 4.5 2.5 -3.6 25.5 -6.6 45 0.2  
5750 -7.2 19.0 150 16 8 5.0 2.7 -4.0 24.8 -7.0 27 0.1  
5500 -6.8 19.8 140 14 7 4.6 2.5 -4.4 24.1 -7.4 9 0.0  
5250 -6.5 20.3 130 13 7 5.7 3.1 -4.7 23.5 -7.7 M M  
5000 -6.1 21.0 115 12 6 1.6 0.9 -5.1 22.8 -8.1 M M  
 
* * * * * * NUMERICAL WEATHER PREDICTION MODEL FORECAST DATA VALID * * * * * *  
 
02/21/2018 AT 0800 MST | 02/21/2018 AT 1100 MST  
|  
K INDEX... -5.0 LI... +6.3 | K INDEX... +4.3 LI... +6.2  
CAPE... 0.0 CIN... 0.0 | CAPE... 0.0 CIN... 0.0  
|  
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 -56.4 -69.5 225 84 43 2.0 1.1 | -56.6 -69.9 225 84 43 2.2 1.2  
45000 -53.3 -63.9 225 81 42 2.1 1.1 | -53.3 -63.9 220 81 42 2.2 1.2  
40000 -53.6 -64.5 225 85 44 -0.7 -0.4 | -53.8 -64.8 225 84 43 -0.8 -0.5  
38000 -54.0 -65.2 225 87 45 -0.3 -0.2 | -54.3 -65.7 225 85 44 -0.9 -0.5  
36000 -53.9 -65.0 225 86 44 0.2 0.1 | -54.8 -66.6 225 87 45 -0.9 -0.5  
34000 -53.8 -64.8 230 84 43 0.2 0.1 | -55.4 -67.7 225 88 45 -1.0 -0.5  
32000 -52.0 -61.6 230 82 42 3.8 2.1 | -53.4 -64.1 225 86 44 4.8 2.6  
30000 -49.7 -57.5 225 81 42 3.8 2.1 | -50.5 -58.9 225 82 42 4.8 2.6  
29000 -48.7 -55.7 225 79 40 3.2 1.8 | -49.2 -56.6 225 80 41 4.2 2.3  
28000 -47.7 -53.9 225 75 39 3.2 1.8 | -47.9 -54.2 225 77 39 4.2 2.3  
27000 -46.8 -52.2 230 72 37 3.2 1.8 | -46.6 -51.9 225 74 38 4.2 2.3  
26000 -45.6 -50.1 230 68 35 7.6 4.2 | -45.2 -49.4 230 71 36 7.7 4.2  
25000 -43.1 -45.6 235 65 33 8.2 4.5 | -42.9 -45.2 230 68 35 7.6 4.2  
24000 -40.7 -41.3 235 61 32 8.2 4.5 | -40.6 -41.1 230 65 33 7.6 4.2  
23000 -38.2 -36.8 240 58 30 7.7 4.2 | -38.4 -37.1 230 62 32 7.2 3.9  
22000 -35.9 -32.6 240 56 29 7.7 4.2 | -36.2 -33.2 230 58 30 7.2 3.9  
21000 -33.6 -28.5 235 53 27 7.6 4.2 | -34.0 -29.2 230 54 28 7.2 3.9  
20000 -31.7 -25.1 235 51 26 4.5 2.5 | -32.0 -25.6 230 50 26 6.5 3.6  
19500 -31.1 -24.0 235 50 26 4.5 2.5 | -31.0 -23.8 230 49 25 6.5 3.5  
19000 -30.4 -22.7 235 48 25 4.5 2.5 | -30.1 -22.2 235 47 24 6.5 3.5  
18500 -29.7 -21.5 235 47 24 4.6 2.5 | -29.1 -20.4 235 45 23 6.5 3.6  
18000 -29.0 -20.2 235 46 24 5.6 3.1 | -28.1 -18.6 235 44 22 7.0 3.8  
17500 -27.9 -18.2 240 44 23 7.9 4.3 | -27.0 -16.6 235 42 21 7.4 4.1  
17000 -26.7 -16.1 240 42 22 7.9 4.4 | -25.9 -14.6 230 40 21 7.4 4.1  
16500 -25.7 -14.3 240 40 21 6.7 3.7 | -24.9 -12.8 230 37 19 6.5 3.5  
16000 -24.6 -12.3 245 39 20 6.9 3.8 | -23.9 -11.0 230 34 18 6.7 3.7  
15500 -23.3 -9.9 245 36 19 4.6 2.5 | -23.1 -9.6 230 32 16 4.5 2.5  
15000 -22.6 -8.7 245 34 18 4.6 2.5 | -22.0 -7.6 230 29 15 4.6 2.5  
14500 -22.1 -7.8 245 32 16 2.8 1.5 | -21.3 -6.3 235 27 14 4.6 2.5  
14000 -21.7 -7.1 240 29 15 2.9 1.6 | -20.6 -5.1 235 25 13 4.6 2.5  
13500 -21.2 -6.2 240 26 14 3.5 1.9 | -19.9 -3.8 230 24 12 4.6 2.5  
13000 -20.7 -5.3 235 24 12 3.3 1.8 | -19.3 -2.7 230 22 11 4.6 2.5  
12500 -20.0 -4.0 230 21 11 6.2 3.4 | -18.6 -1.5 230 20 11 4.6 2.5  
12000 -19.2 -2.6 225 19 10 6.0 3.3 | -18.0 -0.4 225 19 10 4.9 2.7  
11500 -18.1 -0.6 220 17 9 7.7 4.2 | -17.0 1.4 225 18 9 7.6 4.2  
11000 -17.0 1.4 215 16 8 7.6 4.2 | -15.9 3.4 220 18 9 7.4 4.1  
10500 -15.8 3.6 210 15 8 8.0 4.4 | -14.8 5.4 220 17 9 7.3 4.0  
10250 -15.2 4.6 210 15 7 9.0 5.0 | -14.2 6.4 215 16 8 8.2 4.5  
10000 -14.6 5.7 210 14 7 4.9 2.7 | -13.7 7.3 215 16 8 4.7 2.6  
9750 -14.4 6.1 205 14 7 5.8 3.2 | -13.4 7.9 215 15 8 6.4 3.5  
9500 -13.6 7.5 205 13 7 10.7 5.9 | -12.6 9.3 210 14 7 11.4 6.3  
9250 -12.9 8.8 205 13 7 9.3 5.1 | -11.9 10.6 210 13 7 9.6 5.3  
9000 -12.3 9.9 200 13 6 6.4 3.5 | -11.2 11.8 205 12 6 7.5 4.1  
8750 -11.9 10.6 200 12 6 6.3 3.5 | -10.7 12.7 205 11 6 7.4 4.1  
8500 -11.3 11.7 195 12 6 9.0 4.9 | -10.0 14.0 200 11 5 9.3 5.1  
8250 -10.6 12.9 195 11 6 7.2 4.0 | -9.4 15.1 190 10 5 7.3 4.0  
8000 -10.2 13.6 190 11 6 6.0 3.3 | -8.9 16.0 185 9 5 5.6 3.1  
7750 -9.7 14.5 180 11 6 5.5 3.0 | -8.5 16.7 180 8 4 4.8 2.6  
7500 -9.3 15.3 175 11 6 4.7 2.6 | -8.2 17.2 170 7 4 4.9 2.7  
7250 -9.0 15.8 170 11 6 3.8 2.1 | -7.7 18.1 165 6 3 7.2 3.9  
7000 -8.8 16.2 165 11 6 3.2 1.7 | -7.2 19.0 160 6 3 7.8 4.3  
6750 -8.5 16.7 155 11 6 4.3 2.4 | -6.6 20.1 155 5 3 8.2 4.5  
6500 -8.2 17.2 150 11 5 2.8 1.5 | -5.9 21.4 155 5 2 9.9 5.5  
6250 -8.1 17.4 145 9 5 1.5 0.8 | -5.1 22.8 155 4 2 11.0 6.0  
6000 -8.0 17.6 140 8 4 0.2 0.1 | -4.3 24.3 155 4 2 9.9 5.5  
5750 -8.0 17.6 125 6 3 1.5 0.8 | -3.6 25.5 155 4 2 10.4 5.7  
5500 -7.7 18.1 120 6 3 5.2 2.8 | -2.8 27.0 155 4 2 11.8 6.5  
5250 -7.4 18.7 115 5 3 2.5 1.3 | -1.9 28.6 155 4 2 10.7 5.9  
5000 M M M M M M M | M M M M M M M  
 
02/21/2018 AT 1400 MST | 02/21/2018 AT 1700 MST  
|  
K INDEX... +2.5 LI... +4.7 | K INDEX... +13.7 LI... +3.1  
CAPE... +1.9 CIN... -1.8 | CAPE... +1.9 CIN... -4.3  
|  
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 -56.4 -69.5 225 84 43 1.7 1.0 | -56.3 -69.3 230 76 39 1.8 1.0  
45000 -53.6 -64.5 225 80 41 1.8 1.0 | -53.4 -64.1 230 73 38 1.8 1.0  
40000 -53.8 -64.8 230 82 42 -0.5 -0.3 | -52.9 -63.2 230 71 37 0.0 0.0  
38000 -54.1 -65.4 230 83 43 -1.0 -0.5 | -52.9 -63.2 230 70 36 -0.6 -0.3  
36000 -55.0 -67.0 225 86 45 -1.5 -0.8 | -53.9 -65.0 230 75 38 -1.6 -0.9  
34000 -56.0 -68.8 225 90 46 -1.6 -0.9 | -54.8 -66.6 230 79 41 -1.6 -0.9  
32000 -54.4 -65.9 225 92 47 4.2 2.3 | -54.2 -65.6 225 83 43 2.7 1.5  
30000 -51.9 -61.4 225 93 48 4.1 2.3 | -52.4 -62.3 225 87 45 2.7 1.5  
29000 -50.2 -58.4 225 90 47 6.5 3.6 | -51.0 -59.8 225 86 44 6.0 3.3  
28000 -48.2 -54.8 225 86 45 6.5 3.6 | -49.2 -56.6 225 83 43 6.1 3.3  
27000 -46.3 -51.3 225 83 42 6.5 3.6 | -47.4 -53.3 225 79 41 6.1 3.3  
26000 -44.3 -47.7 225 78 40 6.6 3.6 | -45.5 -49.9 225 76 39 6.7 3.7  
25000 -42.3 -44.1 225 73 38 6.6 3.6 | -43.5 -46.3 225 71 36 6.7 3.7  
24000 -40.4 -40.7 225 68 35 6.6 3.6 | -41.5 -42.7 225 66 34 6.7 3.7  
23000 -38.3 -36.9 225 63 32 7.7 4.2 | -39.4 -38.9 225 60 31 8.5 4.7  
22000 -36.0 -32.8 225 58 30 7.6 4.2 | -36.9 -34.4 225 53 27 8.5 4.6  
21000 -33.8 -28.8 225 54 28 7.6 4.2 | -34.4 -29.9 225 45 23 8.4 4.6  
20000 -31.6 -24.9 225 51 26 6.8 3.8 | -32.0 -25.6 225 43 22 7.2 4.0  
19500 -30.6 -23.1 225 50 26 6.8 3.7 | -31.0 -23.8 225 44 23 7.2 3.9  
19000 -29.6 -21.3 225 49 25 6.8 3.7 | -29.9 -21.8 225 45 23 7.2 3.9  
18500 -28.5 -19.3 225 48 25 6.8 3.8 | -28.8 -19.8 225 47 24 7.1 3.9  
18000 -27.5 -17.5 225 47 24 7.0 3.8 | -27.7 -17.9 225 48 25 6.8 3.7  
17500 -26.4 -15.5 220 46 24 7.1 3.9 | -26.8 -16.2 225 45 23 6.4 3.5  
17000 -25.4 -13.7 220 45 23 7.0 3.8 | -25.9 -14.6 225 42 22 6.3 3.4  
16500 -24.5 -12.1 220 43 22 5.3 2.9 | -25.0 -13.0 225 40 21 5.2 2.8  
16000 -23.7 -10.7 215 40 21 5.3 2.9 | -24.2 -11.6 220 39 20 5.3 2.9  
15500 -22.8 -9.0 215 38 19 6.9 3.8 | -23.4 -10.1 220 38 20 5.3 2.9  
15000 -21.2 -6.2 215 34 17 6.2 3.4 | -22.7 -8.9 215 36 19 5.2 2.9  
14500 -20.6 -5.1 210 32 16 2.7 1.5 | -21.2 -6.2 210 35 18 8.2 4.5  
14000 -20.2 -4.4 210 29 15 3.0 1.7 | -20.0 -4.0 205 35 18 8.1 4.4  
13500 -19.5 -3.1 210 27 14 5.6 3.1 | -18.7 -1.7 205 34 18 8.7 4.8  
13000 -18.8 -1.8 215 25 13 5.5 3.0 | -17.4 0.7 200 34 18 8.7 4.7  
12500 -17.7 0.1 215 23 12 8.6 4.7 | -16.2 2.8 200 32 16 8.7 4.8  
12000 -16.5 2.3 210 22 11 8.3 4.6 | -14.9 5.2 205 29 15 8.6 4.7  
11500 -15.3 4.5 210 19 10 7.4 4.1 | -13.8 7.2 200 25 13 6.8 3.7  
11000 -14.2 6.4 210 16 8 7.3 4.0 | -12.7 9.1 200 21 11 6.8 3.7  
10500 -13.2 8.2 205 13 7 6.2 3.4 | -11.8 10.8 195 17 9 5.7 3.1  
10250 -12.8 9.0 205 11 6 7.1 3.9 | -11.4 11.5 190 15 8 6.7 3.7  
10000 -12.3 9.9 200 10 5 4.2 2.3 | -11.0 12.2 185 13 7 3.1 1.7  
9750 -12.0 10.4 200 9 5 4.8 2.7 | -10.8 12.6 185 12 6 3.4 1.9  
9500 -11.5 11.3 195 8 4 8.2 4.5 | -10.4 13.3 180 11 6 7.1 3.9  
9250 -10.9 12.4 190 7 3 7.2 4.0 | -9.9 14.2 175 10 5 6.2 3.4  
9000 -10.4 13.3 190 5 3 6.1 3.3 | -9.5 14.9 165 9 5 4.8 2.6  
8750 -10.0 14.0 185 4 2 5.7 3.1 | -9.1 15.6 165 8 4 4.6 2.5  
8500 -9.5 14.9 180 3 1 6.1 3.4 | -8.7 16.3 155 6 3 5.8 3.2  
8250 -9.1 15.6 165 1 1 6.8 3.7 | -8.3 17.1 135 4 2 5.5 3.0  
8000 -8.5 16.7 150 1 0 8.1 4.4 | -7.9 17.8 115 3 1 5.8 3.2  
7750 -7.9 17.8 000 0 0 9.2 5.0 | -7.4 18.7 080 2 1 6.7 3.7  
7500 -7.1 19.2 000 0 0 10.0 5.5 | -6.9 19.6 045 2 1 7.5 4.1  
7250 -6.4 20.5 000 0 0 9.9 5.4 | -6.3 20.7 020 2 1 8.8 4.8  
7000 -5.6 21.9 000 0 0 10.1 5.5 | -5.6 21.9 010 2 1 10.0 5.5  
6750 -4.9 23.2 000 0 0 9.2 5.0 | -4.8 23.4 360 2 1 9.0 5.0  
6500 -4.2 24.4 000 0 0 9.8 5.4 | -4.2 24.4 350 2 1 9.2 5.1  
6250 -3.4 25.9 315 1 0 11.2 6.1 | -3.5 25.7 345 2 1 9.7 5.3  
6000 -2.6 27.3 310 1 0 10.2 5.6 | -2.7 27.1 340 2 1 10.0 5.5  
5750 -1.9 28.6 305 1 0 9.9 5.4 | -2.0 28.4 335 2 1 8.7 4.8  
5500 -1.1 30.0 305 1 0 10.9 6.0 | -1.5 29.3 330 2 1 6.3 3.4  
5250 -0.3 31.5 305 1 0 11.1 6.1 | -1.0 30.2 335 2 1 6.3 3.4  
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.  
 
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  
 
CLICK HERE TO GO TO PREVIOUS BULLETINS.

The Nexlab CO Page
The Nexlab UT Page Main Text Page