736  
UXUS97 KPUB 261235  
SRGPUB  
 
SOARING FORECAST  
NATIONAL WEATHER SERVICE PUEBLO, COLORADO  
0635 MDT THURSDAY, APRIL 26, 2018  
 
THIS FORECAST IS FOR THURSDAY, APRIL 26, 2018:  
 
IF THE TRIGGER TEMPERATURE OF 50.2 F/10.1 C IS REACHED...THEN  
THERMAL SOARING INDEX....................... GOOD  
MAXIMUM RATE OF LIFT........................ 508 FT/MIN (2.6 M/S)  
MAXIMUM HEIGHT OF THERMALS.................. 13316 FT MSL (5727 FT AGL)  
 
FORECAST MAXIMUM TEMPERATURE................... 53.0 F/12.1 C  
TIME OF TRIGGER TEMPERATURE.................... 1430 MDT  
TIME OF OVERDEVELOPMENT........................ NONE  
MIDDLE/HIGH CLOUDS DURING SOARING WINDOW....... NONE  
SURFACE WINDS DURING SOARING WINDOW............ 20 MPH OR LESS  
HEIGHT OF THE -3 THERMAL INDEX................. 10846 FT MSL (3257 FT AGL)  
THERMAL SOARING OUTLOOK FOR FRIDAY 04/27....... EXCELLENT  
 
WAVE SOARING INDEX............................. NOT AVAILABLE  
 
REMARKS...  
 
EFFECTIVE MAY 18, 2018 THIS PRODUCT WILL NO LONGER BE ISSUED.  
IF YOU HAVE ANY QUESTIONS, PLEASE SEND EMAIL TO:  
JENNIFER.STARK@NOAA.GOV  
PAUL.WOLYN@NOAA.GOV  
 
SUNRISE/SUNSET.................... 06:07:09 / 19:46:57 MDT  
TOTAL POSSIBLE SUNSHINE........... 13 HR 39 MIN 49 SEC (819 MIN 49 SEC)  
ALTITUDE OF SUN AT 12:57:03 MDT... 64.68 DEGREES  
 
UPPER AIR DATA FROM NUMERICAL MODEL FORECAST VALID ON 04/26/2018 AT 0600 MDT  
 
FREEZING LEVEL.................. 9367 FT MSL (1778 FT AGL)  
CONVECTIVE CONDENSATION LEVEL... 17605 FT MSL (10016 FT AGL)  
LIFTED CONDENSATION LEVEL....... 16331 FT MSL (8742 FT AGL)  
LIFTED INDEX.................... +5.0  
K INDEX......................... +14.0  
 
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 -59.3 -74.7 310 16 8 1.1 0.6 M M M M M  
45000 -57.7 -71.9 305 24 13 -0.8 -0.4 M M M M M  
40000 -58.6 -73.5 300 29 15 -0.6 -0.3 M M M M M  
38000 -56.9 -70.4 295 30 16 5.0 2.8 M M M M M  
36000 -53.9 -65.0 290 31 16 5.0 2.8 M M M M M  
34000 -50.6 -59.1 285 31 16 6.8 3.7 M M M M M  
32000 -46.0 -50.8 275 31 16 6.8 3.7 M M M M M  
30000 -41.7 -43.1 275 30 15 7.6 4.1 27.0 80.6 11.8 M M  
29000 -39.5 -39.1 275 29 15 7.6 4.1 26.1 78.9 11.2 M M  
28000 -37.2 -35.0 275 28 14 7.6 4.1 25.3 77.6 10.7 M M  
27000 -35.0 -31.0 275 26 14 7.3 4.0 24.6 76.2 10.3 M M  
26000 -32.8 -27.0 275 25 13 7.3 4.0 23.5 74.4 9.6 M M  
25000 -30.7 -23.3 275 24 12 7.3 4.0 22.6 72.8 8.9 M M  
24000 -28.5 -19.3 280 23 12 7.5 4.1 21.9 71.4 8.4 M M  
23000 -26.2 -15.2 280 22 11 7.7 4.2 21.0 69.8 7.8 M M  
22000 -23.9 -11.0 285 21 11 7.7 4.2 20.3 68.5 7.3 M M  
21000 -21.6 -6.9 285 20 10 6.5 3.6 19.6 67.2 6.7 M M  
20000 -19.7 -3.5 290 19 10 6.5 3.6 18.4 65.0 5.8 M M  
19500 -18.8 -1.8 290 18 9 6.5 3.6 17.8 64.0 5.3 M M  
19000 -17.3 0.9 295 17 9 6.5 3.6 17.0 62.7 4.6 M M  
18500 -16.4 2.5 295 17 9 6.4 3.5 16.5 61.7 4.1 M M  
18000 -15.5 4.1 295 16 8 6.4 3.5 15.9 60.6 3.6 M M  
17500 -14.6 5.7 295 16 8 6.8 3.7 15.4 59.7 3.1 M M  
17000 -13.6 7.5 300 15 8 6.9 3.8 14.9 58.8 2.6 M M  
16500 -12.6 9.3 300 15 8 7.2 3.9 14.4 58.0 2.2 M M  
16000 -11.4 11.5 300 15 8 8.1 4.4 14.1 57.4 1.9 M M  
15500 -10.2 13.6 305 15 8 8.1 4.5 13.8 56.9 1.6 M M  
15000 -9.1 15.6 310 15 8 7.7 4.2 13.5 56.3 1.3 M M  
14500 -8.0 17.6 315 15 8 7.8 4.3 13.2 55.7 1.0 M M  
14000 -6.9 19.6 320 15 8 6.7 3.7 12.8 55.1 0.6 M M  
13500 -5.9 21.4 325 14 7 6.5 3.6 12.3 54.1 0.2 M M  
13000 -4.8 23.4 330 14 7 9.0 4.9 11.9 53.4 -0.2 476 2.4  
12500 -3.5 25.7 335 13 7 6.9 3.8 11.7 53.1 -0.3 421 2.1  
12000 -2.5 27.5 340 14 7 5.2 2.9 11.2 52.2 -0.8 378 1.9  
11750 -2.2 28.0 340 14 7 4.3 2.3 10.8 51.4 -1.2 360 1.8  
11500 -1.9 28.6 345 15 8 4.2 2.3 10.4 50.7 -1.6 343 1.7  
11250 -1.6 29.1 345 16 8 3.7 2.0 9.9 49.8 -2.1 326 1.7  
11000 -1.3 29.7 350 18 9 2.3 1.2 9.4 48.9 -2.5 311 1.6  
10750 -1.2 29.8 350 19 10 1.4 0.8 8.8 47.8 -3.2 300 1.5  
10500 -1.1 30.0 355 20 10 1.3 0.7 8.1 46.6 -3.8 289 1.5  
10250 -0.9 30.4 355 21 11 2.4 1.3 7.5 45.5 -4.4 278 1.4  
10000 -0.7 30.7 360 23 12 3.8 2.1 7.0 44.6 -4.9 264 1.3  
9750 -0.5 31.1 360 23 12 3.5 1.9 6.5 43.8 -5.4 249 1.3  
9500 -0.2 31.6 360 24 12 4.1 2.3 6.1 42.9 -5.9 234 1.2  
9250 0.1 32.2 360 25 13 1.9 1.0 5.6 42.1 -6.4 219 1.1  
9000 0.1 32.2 360 24 13 2.3 1.3 4.9 40.9 -7.0 210 1.1  
8750 0.4 32.7 355 23 12 4.9 2.7 4.5 40.1 -7.5 193 1.0  
8500 0.7 33.3 355 23 12 4.3 2.4 4.1 39.4 -7.9 176 0.9  
8250 1.1 34.0 350 22 11 4.1 2.2 3.7 38.7 -8.4 159 0.8  
8000 1.4 34.5 350 20 10 4.8 2.6 3.3 37.9 -8.8 143 0.7  
7750 1.8 35.2 345 15 8 7.3 4.0 3.0 37.4 -9.1 122 0.6  
7500 M M M M M M M M M M M M  
7250 M M M M M M M M M M M M  
7000 M M M M M M M M M M M M  
6750 M M M M M M M M M M M M  
 
* * * * * * NUMERICAL WEATHER PREDICTION MODEL FORECAST DATA VALID * * * * * *  
 
04/26/2018 AT 0900 MDT | 04/26/2018 AT 1200 MDT  
|  
CAPE... 0.0 LI... +1.2 | CAPE... +19.8 LI... +4.6  
CINH... 0.0 K INDEX... +7.5 | CINH... -5.9 K INDEX... -18.7  
|  
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 -59.8 -75.6 310 15 8 1.1 0.6 | -60.9 -77.6 305 15 8 0.5 0.3  
45000 -58.1 -72.6 315 24 12 0.4 0.2 | -60.1 -76.2 315 23 12 0.7 0.4  
40000 -57.5 -71.5 325 27 14 0.4 0.2 | -59.0 -74.2 335 21 11 0.7 0.4  
38000 -55.1 -67.2 325 26 14 5.9 3.3 | -56.5 -69.7 345 24 12 6.2 3.4  
36000 -51.5 -60.7 325 25 13 5.9 3.2 | -52.8 -63.0 350 28 14 6.2 3.4  
34000 -47.9 -54.2 330 24 12 6.1 3.4 | -48.5 -55.3 360 31 16 6.8 3.7  
32000 -44.2 -47.6 325 23 12 6.1 3.4 | -44.5 -48.1 005 31 16 6.8 3.7  
30000 -40.5 -40.9 325 22 11 6.2 3.4 | -40.4 -40.7 010 32 16 6.9 3.8  
29000 -38.6 -37.5 320 21 11 6.2 3.4 | -38.3 -36.9 010 32 17 6.9 3.8  
28000 -36.7 -34.1 320 21 11 6.2 3.4 | -36.2 -33.2 015 33 17 6.9 3.8  
27000 -34.9 -30.8 320 20 10 6.2 3.4 | -34.2 -29.6 015 33 17 7.0 3.9  
26000 -32.5 -26.5 315 19 10 6.3 3.4 | -32.1 -25.8 015 33 17 7.1 3.9  
25000 -30.6 -23.1 315 18 9 6.3 3.4 | -29.9 -21.8 015 33 17 7.1 3.9  
24000 -28.8 -19.8 315 17 9 5.7 3.1 | -27.8 -18.0 015 33 17 6.8 3.7  
23000 -27.1 -16.8 315 17 9 5.4 3.0 | -25.8 -14.4 015 32 17 6.6 3.6  
22000 -25.5 -13.9 320 17 9 5.4 3.0 | -23.9 -11.0 015 32 16 6.6 3.6  
21000 -24.0 -11.2 325 17 9 4.3 2.4 | -21.9 -7.4 015 30 16 6.1 3.4  
20000 -22.7 -8.9 325 16 8 4.5 2.5 | -19.6 -3.3 010 27 14 6.1 3.3  
19500 -22.0 -7.6 330 16 8 4.5 2.5 | -18.7 -1.7 010 26 13 6.1 3.3  
19000 -21.3 -6.3 330 16 8 4.4 2.4 | -17.8 -0.0 010 25 13 6.1 3.4  
18500 -20.6 -5.1 330 16 8 6.5 3.6 | -17.1 1.2 005 23 12 3.1 1.7  
18000 -19.6 -3.3 335 16 8 6.7 3.7 | -16.6 2.1 360 21 11 3.4 1.9  
17500 -18.6 -1.5 335 16 8 7.4 4.0 | -16.1 3.0 360 19 10 3.4 1.9  
17000 -17.4 0.7 335 16 8 8.4 4.6 | -15.6 3.9 355 17 9 3.5 1.9  
16500 -16.2 2.8 335 15 8 8.4 4.6 | -15.1 4.8 345 16 8 3.9 2.1  
16000 -15.1 4.8 335 15 8 7.0 3.9 | -14.4 6.1 345 15 7 5.0 2.7  
15500 -14.0 6.8 335 14 7 7.0 3.9 | -13.7 7.3 340 14 7 5.0 2.7  
15000 -12.9 8.8 335 14 7 8.8 4.8 | -12.7 9.1 335 13 7 8.5 4.7  
14500 -11.5 11.3 335 13 7 9.0 4.9 | -11.6 11.1 330 12 6 8.3 4.5  
14000 -10.3 13.5 335 12 6 6.1 3.4 | -10.4 13.3 330 11 6 8.2 4.5  
13500 -9.5 14.9 340 12 6 5.3 2.9 | -9.2 15.4 330 11 6 8.5 4.7  
13000 -8.8 16.2 350 12 6 5.1 2.8 | -8.1 17.4 330 11 6 4.7 2.6  
12500 -8.0 17.6 360 13 7 4.4 2.4 | -7.6 18.3 335 11 6 3.8 2.1  
12000 -7.4 18.7 005 13 7 6.2 3.4 | -7.0 19.4 340 12 6 3.8 2.1  
11750 -6.9 19.6 005 14 7 8.3 4.5 | -6.8 19.8 340 12 6 4.0 2.2  
11500 -6.3 20.7 005 15 8 7.2 3.9 | -6.5 20.3 345 13 6 3.4 1.9  
11250 -5.9 21.4 005 16 8 4.9 2.7 | -6.3 20.7 350 13 7 4.2 2.3  
11000 -5.6 21.9 005 16 8 4.6 2.5 | -5.9 21.4 350 13 7 7.1 3.9  
10750 -5.2 22.6 010 17 9 5.3 2.9 | -5.3 22.5 350 13 7 8.0 4.4  
10500 -4.8 23.4 010 18 9 5.6 3.1 | -4.8 23.4 355 13 7 7.7 4.2  
10250 -4.4 24.1 010 19 10 3.9 2.1 | -4.2 24.4 355 12 6 8.2 4.5  
10000 -4.2 24.4 010 20 10 4.3 2.3 | -3.6 25.5 360 12 6 9.4 5.2  
9750 -3.8 25.2 010 20 10 6.3 3.5 | -2.9 26.8 360 12 6 10.0 5.5  
9500 -3.3 26.1 010 20 10 5.6 3.1 | -2.1 28.2 360 12 6 9.9 5.4  
9250 -2.9 26.8 010 20 11 6.3 3.5 | -1.4 29.5 360 12 6 9.5 5.2  
9000 -2.4 27.7 005 20 10 9.0 4.9 | -0.7 30.7 360 12 6 10.4 5.7  
8750 -1.6 29.1 005 18 9 10.5 5.8 | 0.1 32.2 360 12 6 11.4 6.2  
8500 -0.8 30.6 360 17 9 10.2 5.6 | 1.0 33.8 360 12 6 11.2 6.1  
8250 -0.1 31.8 360 16 8 10.4 5.7 | 1.8 35.2 360 12 6 10.4 5.7  
8000 0.9 33.6 355 15 8 16.0 8.8 | 2.8 37.0 360 11 6 19.3 10.6  
7750 4.0 39.2 355 11 6 9.0 4.9 | 4.9 40.8 360 10 5 36.1 19.8  
7500 M M M M M M M | M M M M M M M  
7250 M M M M M M M | M M M M M M M  
7000 M M M M M M M | M M M M M M M  
6750 M M M M M M M | M M M M M M M  
 
04/26/2018 AT 1500 MDT | 04/26/2018 AT 1800 MDT  
|  
CAPE... +2.9 LI... +5.0 | CAPE... 0.0 LI... +3.7  
CINH... 0.0 K INDEX... -13.3 | CINH... 0.0 K INDEX... -9.5  
|  
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 -61.1 -78.0 305 15 8 -0.2 -0.1 | -61.5 -78.7 310 15 8 -1.0 -0.5  
45000 -61.3 -78.3 320 19 10 1.8 1.0 | -62.8 -81.0 325 20 10 1.5 0.8  
40000 -58.8 -73.8 345 19 10 1.6 0.9 | -60.9 -77.6 350 20 10 1.4 0.8  
38000 -56.5 -69.7 350 21 11 4.9 2.7 | -58.1 -72.6 355 21 11 6.0 3.3  
36000 -53.6 -64.5 355 24 13 4.9 2.7 | -54.5 -66.1 360 21 11 6.0 3.3  
34000 -49.6 -57.3 360 27 14 7.5 4.1 | -50.5 -58.9 005 22 11 7.7 4.2  
32000 -45.1 -49.2 005 26 13 7.5 4.1 | -45.3 -49.5 005 22 11 7.7 4.2  
30000 -40.6 -41.1 005 26 13 7.7 4.2 | -40.5 -40.9 010 22 11 8.2 4.5  
29000 -38.3 -36.9 005 26 13 7.7 4.2 | -38.1 -36.6 010 21 11 8.2 4.5  
28000 -36.0 -32.8 010 25 13 7.7 4.2 | -35.6 -32.1 015 21 11 8.2 4.5  
27000 -33.7 -28.7 010 25 13 7.0 3.8 | -33.1 -27.6 015 20 10 8.3 4.5  
26000 -31.6 -24.9 010 25 13 7.1 3.9 | -30.6 -23.1 015 20 10 8.3 4.5  
25000 -29.5 -21.1 010 25 13 7.1 3.9 | -28.2 -18.8 015 20 10 8.3 4.6  
24000 -27.4 -17.3 005 25 13 7.2 4.0 | -25.8 -14.4 010 20 10 6.5 3.6  
23000 -25.2 -13.4 010 25 13 7.2 4.0 | -23.8 -10.8 010 20 10 6.7 3.7  
22000 -23.0 -9.4 010 25 13 7.2 4.0 | -21.8 -7.2 010 20 10 6.7 3.7  
21000 -20.9 -5.6 010 25 13 7.7 4.2 | -19.8 -3.6 010 19 10 6.6 3.6  
20000 -18.6 -1.5 010 24 12 7.6 4.2 | -17.9 -0.2 010 18 9 6.6 3.6  
19500 -16.8 1.8 015 23 12 7.6 4.2 | -16.4 2.5 010 17 9 6.6 3.6  
19000 -15.7 3.7 015 22 12 7.4 4.0 | -15.4 4.3 010 17 9 6.8 3.7  
18500 -14.7 5.5 015 21 11 6.6 3.6 | -14.4 6.1 005 16 8 7.0 3.9  
18000 -13.7 7.3 015 20 10 6.6 3.6 | -13.3 8.1 005 16 8 7.1 3.9  
17500 -12.7 9.1 015 19 10 6.4 3.5 | -12.3 9.9 360 15 8 6.4 3.5  
17000 -11.7 10.9 015 19 10 6.2 3.4 | -11.4 11.5 360 15 8 6.4 3.5  
16500 -10.8 12.6 015 18 9 4.4 2.4 | -10.4 13.3 360 14 7 6.6 3.6  
16000 -10.4 13.3 005 17 9 2.4 1.3 | -9.4 15.1 355 14 7 6.7 3.7  
15500 -10.1 13.8 360 17 9 2.4 1.3 | -8.4 16.9 355 14 7 6.1 3.4  
15000 -9.6 14.7 350 16 8 3.4 1.8 | -7.6 18.3 350 14 7 4.1 2.2  
14500 -9.2 15.4 340 16 8 3.0 1.6 | -7.0 19.4 345 15 8 4.1 2.3  
14000 -8.3 17.1 330 16 8 9.5 5.2 | -6.2 20.8 340 14 7 6.9 3.8  
13500 -7.0 19.4 325 15 8 9.7 5.3 | -5.3 22.5 335 14 7 6.8 3.8  
13000 -6.1 21.0 325 14 7 3.2 1.7 | -4.1 24.6 330 13 7 9.8 5.4  
12500 -5.8 21.6 330 13 7 2.2 1.2 | -2.8 27.0 325 13 6 9.6 5.3  
12000 -5.4 22.3 330 12 6 4.2 2.3 | -1.8 28.8 330 12 6 4.0 2.2  
11750 -5.1 22.8 335 11 6 5.1 2.8 | -1.5 29.3 330 11 6 4.2 2.3  
11500 -4.8 23.4 340 10 5 2.7 1.5 | -1.3 29.7 335 10 5 3.7 2.1  
11250 -4.7 23.5 345 10 5 3.9 2.1 | -1.1 30.0 335 10 5 3.4 1.8  
11000 -4.2 24.4 345 9 5 9.3 5.1 | -0.8 30.6 335 10 5 3.6 2.0  
10750 -3.4 25.9 350 9 5 10.0 5.5 | -0.6 30.9 340 9 4 3.9 2.1  
10500 -2.7 27.1 350 9 5 10.1 5.5 | -0.3 31.5 340 8 4 2.8 1.6  
10250 -2.0 28.4 350 9 5 9.1 5.0 | -0.1 31.8 345 7 4 5.2 2.8  
10000 -1.3 29.7 350 9 5 9.2 5.1 | 0.5 32.9 350 7 3 9.4 5.2  
9750 -0.6 30.9 350 9 5 10.3 5.6 | 1.2 34.2 355 6 3 9.8 5.4  
9500 0.2 32.4 350 9 5 9.9 5.5 | 1.9 35.4 355 6 3 9.7 5.3  
9250 0.9 33.6 350 9 5 8.9 4.9 | 2.6 36.7 355 6 3 8.9 4.9  
9000 1.6 34.9 350 9 5 10.1 5.6 | 3.3 37.9 355 6 3 9.7 5.3  
8750 2.4 36.3 350 9 5 11.8 6.5 | 4.1 39.4 360 6 3 10.9 6.0  
8500 3.3 37.9 350 9 5 11.3 6.2 | 4.9 40.8 360 6 3 10.4 5.7  
8250 4.1 39.4 350 9 5 10.4 5.7 | 5.6 42.1 360 6 3 9.6 5.3  
8000 5.0 41.0 355 9 5 18.4 10.1 | 6.4 43.5 360 6 3 13.5 7.4  
7750 7.0 44.6 355 8 4 33.2 18.2 | 7.7 45.9 360 6 3 21.2 11.6  
7500 M M M M M M M | M M M M M M M  
7250 M M M M M M M | M M M M M M M  
7000 M M M M M M M | M M M M M M M  
6750 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 THE AIR FORCE ACADEMY  
IN COLORADO SPRINGS, COLORADO AT  
 
NORTH LATITUDE: 38 DEG 58 MIN 48.000 SEC  
WEST LONGITUDE: 104 DEG 49 MIN 12.000 SEC  
ELEVATION: 6572 FEET (2003 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  
 
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