035
UXUS97 KBOU 090006
SRGBOU
SOARING FORECAST
NATIONAL WEATHER SERVICE DENVER/BOULDER, COLORADO
606 PM MDT TUESDAY JULY 8, 2008
THIS FORECAST IS FOR WEDNESDAY JULY 9, 2008:
IF THE TRIGGER TEMPERATURE OF 83.2 F/28.4 C IS REACHED...THEN
THERMAL SOARING INDEX....................... EXCELLENT
MAXIMUM RATE OF LIFT........................ 1268 FT/MIN (6.4 M/S)
MAXIMUM HEIGHT OF THERMALS.................. 18744 FT MSL (13421 FT AGL)
FORECAST MAXIMUM TEMPERATURE................... 92.0 F/33.8 C
TIME OF TRIGGER TEMPERATURE.................... 1100 MDT
TIME OF OVERDEVELOPMENT........................ 1800 MDT
MIDDLE/HIGH CLOUDS DURING SOARING WINDOW....... NONE
SURFACE WINDS DURING SOARING WINDOW............ 20 MPH OR LESS
HEIGHT OF THE -3 THERMAL INDEX................. 13789 FT MSL (8466 FT AGL)
THERMAL SOARING OUTLOOK FOR THURSDAY 07/10..... EXCELLENT
WAVE SOARING INDEX............................. POOR
WAVE SOARING INDEX TREND (TO 1800 MDT)......... NNO CHANGE
HEIGHT OF STABLE LAYER (12-18K FT MSL)......... NONE
WEAK PVA/NVA (THROUGH 1800 MDT)................ WEAK NVA
POTENTIAL HEIGHT OF WAVE....................... 16389 FT MSL (11066 FT AGL)
WAVE SOARING OUTLOOK FOR THURSDAY 07/10........ POOR
REMARKS... NONE
SUNRISE/SUNSET.................... 05:40:09 / 20:29:28 MDT
TOTAL POSSIBLE SUNSHINE........... 14 HR 49 MIN 19 SEC (889 MIN 19 SEC)
ALTITUDE OF SUN AT 13:04:47 MDT... 72.44 DEGREES
UPPER AIR DATA FROM NUMERICAL MODEL FORECAST VALID ON 07/09/2008 AT 0600 MDT
FREEZING LEVEL.................. 15690 FT MSL (10367 FT AGL)
CONVECTIVE CONDENSATION LEVEL... 16534 FT MSL (11211 FT AGL)
LIFTED CONDENSATION LEVEL....... 17315 FT MSL (11992 FT AGL)
LIFTED INDEX.................... -3.7
K INDEX......................... +18.2
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 -64.3 -83.7 272 28 15 2.2 1.2 84.5 184.1 29.9 M M
45000 -59.6 -75.3 266 33 17 4.9 2.7 67.9 154.2 21.7 M M
40000 -52.0 -61.6 266 31 16 5.8 3.2 57.5 135.5 16.2 M M
38000 -48.5 -55.3 268 27 14 5.9 3.2 53.7 128.7 14.0 M M
36000 -45.0 -49.0 271 22 11 5.8 3.2 50.8 123.4 12.3 M M
34000 -41.2 -42.2 290 16 8 6.5 3.6 47.7 117.9 10.4 M M
32000 -36.8 -34.2 330 15 8 6.3 3.5 44.9 112.9 8.6 M M
30000 -32.4 -26.3 335 13 7 7.5 4.1 42.9 109.1 7.2 M M
29000 -30.2 -22.4 335 12 6 7.5 4.1 42.0 107.6 6.7 M M
28000 -27.9 -18.2 334 11 6 7.6 4.2 41.3 106.3 6.2 M M
27000 -25.7 -14.3 331 11 6 7.7 4.2 40.4 104.7 5.5 M M
26000 -23.4 -10.1 327 11 6 7.7 4.2 39.6 103.3 4.9 M M
25000 -21.1 -6.0 323 11 6 7.7 4.2 39.0 102.1 4.5 M M
24000 -18.9 -2.0 322 10 5 7.2 4.0 38.0 100.3 3.7 M M
23000 -16.8 1.8 322 9 5 7.2 4.0 37.0 98.7 2.9 M M
22000 -14.6 5.7 321 8 4 7.3 4.0 36.2 97.2 2.2 M M
21000 -12.4 9.7 334 8 4 7.4 4.1 35.3 95.5 1.5 M M
20000 -10.2 13.6 348 8 4 7.4 4.1 34.5 94.1 0.8 M M
19500 -9.0 15.8 354 8 4 7.4 4.1 34.1 93.4 0.6 M M
19000 -7.9 17.8 360 9 4 7.7 4.2 33.8 92.8 0.2 M M
18500 -6.8 19.8 004 9 5 7.7 4.2 33.4 92.1 -0.1 1254 6.4
18000 -5.6 21.9 007 10 5 7.7 4.2 33.1 91.5 -0.4 1205 6.1
17500 -4.5 23.9 011 10 5 7.8 4.3 32.7 90.9 -0.7 1156 5.9
17000 -2.8 27.0 015 10 5 7.9 4.3 32.2 90.0 -1.2 1082 5.5
16500 -1.6 29.1 019 10 5 7.9 4.3 31.9 89.4 -1.6 1033 5.2
16000 -0.5 31.1 023 9 5 8.0 4.4 31.6 88.9 -1.9 984 5.0
15500 0.7 33.3 029 9 4 8.2 4.5 31.3 88.4 -2.2 934 4.7
15000 1.9 35.4 037 8 4 8.1 4.5 31.0 87.9 -2.5 884 4.5
14500 3.1 37.6 044 7 4 8.8 4.9 30.8 87.5 -2.7 833 4.2
14000 4.3 39.7 051 7 4 8.9 4.9 30.7 87.2 -2.9 780 4.0
13500 5.6 42.1 056 6 3 8.9 4.9 30.6 87.0 -3.1 727 3.7
13000 6.9 44.4 054 5 3 8.9 4.9 30.4 86.7 -3.4 674 3.4
12500 8.1 46.6 051 5 2 8.7 4.8 30.3 86.5 -3.6 621 3.2
12000 9.4 48.9 047 4 2 8.6 4.7 30.1 86.1 -3.8 570 2.9
11500 10.6 51.1 042 3 2 8.6 4.7 29.9 85.8 -4.1 519 2.6
11000 11.8 53.2 049 3 1 8.8 4.8 29.7 85.5 -4.3 466 2.4
10500 13.1 55.6 060 2 1 9.0 4.9 29.6 85.2 -4.5 413 2.1
10250 13.8 56.8 067 2 1 9.5 5.2 29.5 85.2 -4.6 385 2.0
10000 14.5 58.1 075 2 1 9.5 5.2 29.5 85.1 -4.6 357 1.8
9750 15.2 59.4 082 2 1 9.6 5.3 29.5 85.1 -4.6 328 1.7
9500 15.9 60.6 089 2 1 9.2 5.1 29.5 85.1 -4.7 300 1.5
9250 16.6 61.9 091 2 1 8.7 4.8 29.4 85.0 -4.7 272 1.4
9000 17.2 63.0 093 2 1 8.7 4.8 29.3 84.8 -4.8 246 1.2
8750 17.9 64.2 094 2 1 8.9 4.9 29.3 84.7 -4.9 219 1.1
8500 18.5 65.3 096 2 1 8.1 4.4 29.2 84.5 -5.0 192 1.0
8250 19.1 66.4 092 2 1 7.2 4.0 29.0 84.2 -5.2 169 0.9
8000 19.6 67.3 085 1 1 7.4 4.0 28.8 83.9 -5.5 146 0.7
7750 20.1 68.2 074 1 1 7.4 4.1 28.6 83.5 -5.7 123 0.6
7500 20.6 69.1 060 1 0 5.2 2.9 28.4 83.1 -5.9 101 0.5
7250 20.8 69.4 000 0 0 3.3 1.8 28.0 82.3 -6.4 86 0.4
7000 21.1 70.0 231 1 0 4.7 2.6 27.5 81.5 -6.9 70 0.4
6750 21.4 70.5 233 2 1 1.1 0.6 27.1 80.7 -7.4 55 0.3
6500 21.1 70.0 234 3 1 -7.5 -4.1 26.1 78.9 -8.4 56 0.3
6250 20.4 68.7 234 4 2 -10.9 -6.0 24.6 76.2 -9.9 71 0.4
6000 19.6 67.3 234 6 3 -8.3 -4.5 23.1 73.6 -11.4 86 0.4
5750 18.9 66.0 234 7 4 -15.4 -8.5 21.6 70.9 -12.9 101 0.5
5500 17.0 62.6 220 6 3 -31.9 -17.5 19.0 66.3 -15.6 150 0.8
* * * * * * NUMERICAL WEATHER PREDICTION MODEL FORECAST DATA VALID * * * * * *
07/09/2008 AT 0900 MDT | 07/09/2008 AT 1200 MDT
|
K INDEX... +19.3 | K INDEX... +22.9
|
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 -63.8 -82.8 283 29 15 2.0 1.1 | -63.9 -83.0 287 28 14 2.1 1.2
45000 -59.5 -75.1 270 32 17 4.5 2.5 | -59.6 -75.3 272 32 17 4.5 2.5
40000 -52.5 -62.5 266 29 15 5.8 3.2 | -52.6 -62.7 259 31 16 6.1 3.3
38000 -49.0 -56.2 265 25 13 5.9 3.2 | -48.9 -56.0 259 30 15 6.1 3.4
36000 -45.5 -49.9 264 22 11 5.8 3.2 | -45.2 -49.4 260 29 15 6.1 3.3
34000 -41.2 -42.2 278 16 8 7.4 4.0 | -40.6 -41.1 268 21 11 6.9 3.8
32000 -36.3 -33.3 314 12 6 7.3 4.0 | -36.5 -33.7 284 14 7 6.8 3.7
30000 -31.7 -25.1 318 12 6 7.6 4.2 | -31.7 -25.1 308 13 7 8.2 4.5
29000 -29.4 -20.9 317 12 6 7.6 4.2 | -29.2 -20.6 319 14 7 8.2 4.5
28000 -27.1 -16.8 317 12 6 7.5 4.1 | -26.8 -16.2 328 15 8 8.1 4.4
27000 -24.9 -12.8 318 13 7 7.5 4.1 | -24.4 -11.9 325 16 8 8.1 4.4
26000 -22.7 -8.9 318 14 7 7.5 4.1 | -22.0 -7.6 323 18 9 8.1 4.4
25000 -20.4 -4.7 319 15 8 7.4 4.0 | -19.5 -3.1 321 19 10 7.6 4.2
24000 -18.4 -1.1 321 16 8 6.8 3.7 | -17.8 -0.0 321 18 10 5.7 3.2
23000 -16.4 2.5 322 16 8 6.8 3.7 | -16.0 3.2 321 18 9 5.8 3.2
22000 -14.4 6.1 324 17 9 6.8 3.7 | -14.3 6.3 322 17 9 6.1 3.3
21000 -12.4 9.7 327 15 8 6.8 3.7 | -12.4 9.7 324 16 8 6.6 3.6
20000 -10.4 13.3 331 13 7 6.8 3.7 | -10.4 13.3 326 15 8 6.7 3.7
19500 -9.4 15.1 333 12 6 6.9 3.8 | -9.5 14.9 328 14 7 6.8 3.7
19000 -8.4 16.9 339 11 6 6.2 3.4 | -8.5 16.7 330 13 7 6.1 3.4
18500 -7.6 18.3 350 10 5 6.3 3.5 | -7.6 18.3 333 11 6 6.3 3.4
18000 -6.7 19.9 003 9 5 7.1 3.9 | -6.2 20.8 340 8 4 8.0 4.4
17500 -4.9 23.2 017 9 5 8.1 4.5 | -5.1 22.8 349 6 3 7.9 4.3
17000 -3.7 25.3 027 9 5 8.2 4.5 | -3.9 25.0 004 5 3 8.2 4.5
16500 -2.5 27.5 033 9 5 8.4 4.6 | -2.7 27.1 026 4 2 8.4 4.6
16000 -1.2 29.8 040 9 5 8.4 4.6 | -1.5 29.3 053 4 2 8.5 4.7
15500 0.0 32.0 045 8 4 8.7 4.8 | -0.2 31.6 071 4 2 8.7 4.8
15000 1.3 34.3 049 7 4 8.7 4.8 | 1.1 34.0 089 3 2 8.7 4.8
14500 2.6 36.7 056 6 3 8.4 4.6 | 2.4 36.3 115 3 2 8.8 4.8
14000 3.8 38.8 066 5 2 8.4 4.6 | 3.7 38.7 145 3 2 8.8 4.8
13500 5.0 41.0 080 4 2 9.0 4.9 | 5.0 41.0 162 4 2 9.2 5.0
13000 6.3 43.3 088 3 2 9.2 5.1 | 6.3 43.3 166 5 3 9.3 5.1
12500 7.6 45.7 097 3 2 9.0 4.9 | 7.7 45.9 168 6 3 9.4 5.1
12000 8.9 48.0 106 3 2 8.8 4.8 | 9.0 48.2 167 6 3 9.4 5.1
11500 10.2 50.4 114 3 2 9.1 5.0 | 10.4 50.7 167 7 3 9.4 5.2
11000 11.6 52.9 123 3 2 9.5 5.2 | 11.8 53.2 166 7 4 9.5 5.2
10500 13.0 55.4 129 4 2 9.2 5.0 | 13.2 55.8 165 7 4 9.5 5.2
10250 13.6 56.5 132 4 2 8.7 4.8 | 13.9 57.0 164 7 4 9.5 5.2
10000 14.3 57.7 135 4 2 8.7 4.8 | 14.6 58.3 163 7 4 9.5 5.2
9750 15.0 59.0 137 5 2 8.8 4.8 | 15.3 59.5 163 7 4 9.5 5.2
9500 15.6 60.1 139 5 3 8.4 4.6 | 15.9 60.6 162 7 4 9.7 5.3
9250 16.2 61.2 140 5 3 8.0 4.4 | 16.7 62.1 162 7 3 9.9 5.4
9000 16.8 62.2 141 5 3 8.0 4.4 | 17.4 63.3 161 7 3 9.9 5.4
8750 17.4 63.3 142 6 3 8.3 4.6 | 18.1 64.6 160 7 3 9.9 5.4
8500 17.9 64.2 143 6 3 6.8 3.7 | 18.9 66.0 160 6 3 9.9 5.4
8250 18.3 64.9 149 6 3 5.4 2.9 | 19.6 67.3 159 6 3 9.8 5.4
8000 18.7 65.7 154 6 3 5.8 3.2 | 20.3 68.5 158 6 3 9.8 5.4
7750 19.1 66.4 158 7 3 5.6 3.1 | 21.0 69.8 157 6 3 9.9 5.4
7500 19.5 67.1 161 6 3 4.1 2.2 | 21.8 71.2 157 6 3 9.9 5.4
7250 19.7 67.5 159 5 3 3.1 1.7 | 22.5 72.5 157 6 3 10.0 5.5
7000 19.9 67.8 156 4 2 3.4 1.9 | 23.2 73.8 157 5 3 9.9 5.4
6750 20.2 68.4 150 3 2 3.3 1.8 | 24.0 75.2 157 5 3 10.2 5.6
6500 20.4 68.7 144 2 1 3.0 1.7 | 24.8 76.6 158 5 3 10.6 5.8
6250 20.6 69.1 137 2 1 3.2 1.8 | 25.5 77.9 158 5 3 11.0 6.1
6000 20.8 69.4 121 1 1 2.4 1.3 | 26.3 79.3 159 5 3 9.7 5.3
5750 21.1 70.0 087 1 0 10.9 6.0 | 27.2 81.0 159 5 2 17.6 9.7
5500 22.6 72.7 109 1 0 27.3 15.0 | 29.1 84.4 155 5 3 34.3 18.8
07/09/2008 AT 1500 MDT | 07/09/2008 AT 1800 MDT
|
K INDEX... +25.6 | K INDEX... +27.6
|
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 -64.4 -83.9 293 25 13 2.3 1.3 | -64.7 -84.5 306 25 13 2.4 1.3
45000 -59.6 -75.3 278 31 16 5.0 2.8 | -59.5 -75.1 302 29 15 5.7 3.1
40000 -52.0 -61.6 263 34 18 5.8 3.2 | -51.0 -59.8 287 26 14 5.5 3.0
38000 -48.4 -55.1 267 33 17 5.9 3.2 | -47.7 -53.9 284 27 14 5.5 3.0
36000 -44.9 -48.8 271 31 16 5.8 3.2 | -44.4 -47.9 281 27 14 5.4 3.0
34000 -40.4 -40.7 275 26 14 6.9 3.8 | -40.0 -40.0 288 24 12 6.8 3.7
32000 -36.3 -33.3 281 22 11 6.7 3.7 | -35.9 -32.6 297 22 11 6.7 3.7
30000 -31.5 -24.7 289 18 9 8.0 4.4 | -31.2 -24.2 304 20 10 8.0 4.4
29000 -29.1 -20.4 295 16 8 8.0 4.4 | -28.8 -19.8 307 19 10 8.0 4.4
28000 -26.7 -16.1 303 15 8 8.5 4.7 | -26.4 -15.5 311 19 10 8.1 4.4
27000 -24.1 -11.4 311 15 8 8.6 4.7 | -24.0 -11.2 315 19 10 8.1 4.5
26000 -21.5 -6.7 319 16 8 8.6 4.7 | -21.6 -6.9 318 20 10 8.1 4.5
25000 -18.9 -2.0 326 17 9 8.1 4.4 | -19.2 -2.6 322 20 10 7.8 4.3
24000 -17.2 1.0 327 18 9 5.2 2.9 | -17.3 0.9 320 20 10 5.9 3.2
23000 -15.7 3.7 327 19 10 5.3 2.9 | -15.6 3.9 317 20 10 5.9 3.3
22000 -14.1 6.6 327 19 10 5.8 3.2 | -13.9 7.0 315 20 10 6.2 3.4
21000 -12.2 10.0 323 18 9 6.8 3.7 | -11.9 10.6 308 18 9 6.9 3.8
20000 -10.1 13.8 319 16 8 6.8 3.7 | -9.9 14.2 300 17 9 6.9 3.8
19500 -9.1 15.6 316 16 8 6.7 3.7 | -8.9 16.0 296 17 9 6.9 3.8
19000 -8.0 17.6 314 15 7 8.6 4.7 | -7.9 17.8 291 16 8 7.5 4.1
18500 -6.8 19.8 311 13 7 8.5 4.7 | -6.8 19.8 286 14 7 7.5 4.1
18000 -4.9 23.2 306 11 6 8.4 4.6 | -5.2 22.6 275 11 6 7.8 4.3
17500 -3.7 25.3 303 10 5 8.3 4.6 | -4.0 24.8 265 10 5 7.8 4.3
17000 -2.5 27.5 298 8 4 7.7 4.2 | -2.9 26.8 254 10 5 8.0 4.4
16500 -1.5 29.3 281 6 3 7.0 3.9 | -1.7 28.9 242 9 5 8.4 4.6
16000 -0.5 31.1 247 4 2 7.1 3.9 | -0.5 31.1 229 9 5 8.4 4.6
15500 0.6 33.1 212 5 2 8.8 4.9 | 0.9 33.6 222 9 5 9.7 5.3
15000 1.8 35.2 190 6 3 8.7 4.8 | 2.3 36.1 219 9 5 9.6 5.3
14500 3.1 37.6 179 7 4 9.9 5.4 | 3.7 38.7 213 9 5 9.6 5.3
14000 4.6 40.3 176 8 4 9.9 5.5 | 5.2 41.4 205 9 5 9.6 5.3
13500 6.0 42.8 173 8 4 9.8 5.4 | 6.6 43.9 197 10 5 9.6 5.3
13000 7.5 45.5 171 8 4 9.8 5.4 | 8.0 46.4 192 11 5 9.6 5.3
12500 8.9 48.0 169 9 5 9.7 5.3 | 9.5 49.1 187 11 6 9.7 5.3
12000 10.4 50.7 168 9 5 9.7 5.3 | 10.9 51.6 183 12 6 9.8 5.4
11500 11.8 53.2 166 9 5 9.8 5.4 | 12.4 54.3 179 13 6 9.8 5.4
11000 13.3 55.9 165 9 5 10.0 5.5 | 13.9 57.0 178 13 7 9.8 5.4
10500 14.8 58.6 164 10 5 9.9 5.4 | 15.3 59.5 176 13 7 9.8 5.4
10250 15.6 60.1 164 10 5 9.7 5.3 | 16.1 61.0 176 13 7 9.9 5.4
10000 16.3 61.3 164 10 5 9.7 5.3 | 16.8 62.2 175 14 7 9.9 5.5
9750 17.0 62.6 163 10 5 9.6 5.3 | 17.5 63.5 174 14 7 10.0 5.5
9500 17.7 63.9 163 10 5 9.8 5.4 | 18.3 64.9 173 14 7 9.9 5.4
9250 18.5 65.3 163 10 5 10.1 5.5 | 19.0 66.2 173 14 7 9.8 5.4
9000 19.2 66.6 163 10 5 10.1 5.5 | 19.8 67.6 172 14 7 9.7 5.3
8750 20.0 68.0 162 10 5 10.1 5.5 | 20.5 68.9 171 14 7 9.7 5.3
8500 20.7 69.3 162 10 5 10.0 5.5 | 21.2 70.2 171 14 7 9.8 5.4
8250 21.5 70.7 162 10 5 9.9 5.4 | 22.0 71.6 170 14 7 10.0 5.5
8000 22.2 72.0 161 10 5 9.9 5.4 | 22.7 72.9 170 14 7 10.0 5.5
7750 23.0 73.4 161 10 5 9.9 5.4 | 23.4 74.1 169 14 7 10.0 5.5
7500 23.7 74.7 161 10 5 10.1 5.5 | 24.2 75.6 169 15 7 9.9 5.4
7250 24.5 76.1 160 10 5 10.3 5.6 | 24.9 76.8 168 15 7 9.7 5.3
7000 25.2 77.4 160 10 5 10.2 5.6 | 25.7 78.3 168 15 8 9.8 5.3
6750 26.0 78.8 160 10 5 10.3 5.7 | 26.4 79.5 167 15 8 9.7 5.3
6500 26.8 80.2 160 10 5 10.4 5.7 | 27.1 80.8 167 15 8 10.3 5.6
6250 27.5 81.5 160 10 5 10.9 6.0 | 27.9 82.2 166 14 7 10.9 6.0
6000 28.3 82.9 160 10 5 9.3 5.1 | 28.7 83.7 166 14 7 10.1 5.5
5750 29.1 84.4 159 10 5 15.4 8.5 | 29.5 85.1 165 14 7 12.8 7.0
5500 30.9 87.6 158 10 5 32.2 17.7 | 30.7 87.3 165 13 7 21.2 11.6
________________________________________________________________________________
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 NEAR THE OLD STAPLETON
AIRPORT SITE IN DENVER, COLORADO AT
NORTH LATITUDE: 39 DEG 46 MIN 5.016 SEC
WEST LONGITUDE: 104 DEG 52 MIN 9.984 SEC
ELEVATION: 5285 FEET (1611 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:
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 - 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, CIRROSTATUS, 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.
071806
CLICK HERE TO GO TO PREVIOUS BULLETINS.
Main Text Page