National Weather Service Text Product
AFOS product SRGBOU
Dates interpreted at 00:00 UTCDisplaying AFOS PIL: SRGBOU
Product Timestamp: 2012-03-20 00:26 UTC
Bulk Download
Bulk Download
Bulk Download Help
This bulk download tool provides the NWS text
in a raw form, hopefully directly usable by your processing system.
You can either provide a complete 6-character PIL/AFOS ID or provide
the 3-character base ID (e.g., AFD). The start and end
dates represent 00 UTC for those dates. The Zip format is useful as
the filenames will have the product timestamp, which is useful for
when the product format has ambiguous timestamps.
837
UXUS97 KBOU 200026
SRGBOU
Soaring Forecast
National Weather Service Denver/Boulder, Colorado
626 PM MDT Monday March 19, 2012
This forecast is for Tuesday March 20, 2012:
If the trigger temperature of 34.7 F/1.5 C is reached...then
Thermal Soaring Index....................... Excellent
Maximum rate of lift........................ 1156 ft/min (5.9 m/s)
Maximum height of thermals.................. 18764 ft MSL (13441 ft AGL)
Forecast maximum temperature................... 51.0 F/11.0 C
Time of trigger temperature.................... 0915 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................. 14916 ft MSL (9593 ft AGL)
Thermal soaring outlook for Wednesday 03/21.... Good
Wave Soaring Index............................. Poor
Wave Soaring Index trend (to 1800 MDT)......... No change
Height of stable layer (12-18K ft MSL)......... None
Weak PVA/NVA (through 1800 MDT)................ Weak PVA
Potential height of wave....................... 14406 ft MSL (9083 ft AGL)
Wave soaring outlook for Wednesday 03/21....... Fair
Remarks... None
Sunrise/Sunset.................... 07:02:00 / 19:11:01 MDT
Total possible sunshine........... 12 hr 9 min 1 sec (729 min 1 sec)
Altitude of sun at 13:06:41 MDT... 50.47 degrees
Upper air data from numerical model forecast valid on 03/20/2012 at 0600 MDT
Freezing level.................. Entire airmass below 32 F / 0 C
Convective condensation level... 9839 ft MSL (4516 ft AGL)
Lifted condensation level....... 13370 ft MSL (8047 ft AGL)
Lifted index.................... -1.1
K index......................... +13.4
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 -54.3 -65.7 196 6 3 2.3 1.3 108.7 227.6 56.2 M M
45000 -50.8 -59.4 193 9 5 2.3 1.3 91.5 196.7 49.3 M M
40000 -47.0 -52.6 174 18 9 2.5 1.3 73.0 163.4 40.8 M M
38000 -45.6 -50.1 171 21 11 1.6 0.9 66.7 152.1 37.6 M M
36000 -44.6 -48.3 169 21 11 1.6 0.9 59.2 138.5 33.4 M M
34000 -43.6 -46.5 168 20 10 1.6 0.9 52.6 126.6 29.6 M M
32000 -42.9 -45.2 168 22 12 1.1 0.6 45.3 113.5 25.1 M M
30000 -42.2 -44.0 169 26 13 1.1 0.6 38.4 101.1 20.6 M M
29000 -41.9 -43.4 169 28 14 0.2 0.1 33.9 93.0 17.6 M M
28000 -41.9 -43.4 169 28 15 0.2 0.1 30.0 86.0 14.8 M M
27000 -41.8 -43.2 168 29 15 0.2 0.1 26.4 79.4 12.2 M M
26000 -41.7 -43.1 167 29 15 1.0 0.5 22.9 73.2 9.6 M M
25000 -41.4 -42.5 152 23 12 1.2 0.7 19.5 67.1 7.1 M M
24000 -41.0 -41.8 130 19 10 1.2 0.7 16.3 61.3 4.6 M M
23000 -40.5 -40.9 104 18 9 6.3 3.4 13.5 56.2 2.3 M M
22000 -38.0 -36.4 098 14 7 8.1 4.5 12.8 55.0 1.8 M M
21000 -35.6 -32.1 087 10 5 8.2 4.5 12.2 54.0 1.4 M M
20000 -33.2 -27.8 062 6 3 7.6 4.2 11.6 52.9 0.9 M M
19500 -32.1 -25.8 033 5 3 7.6 4.2 11.2 52.2 0.5 M M
19000 -30.9 -23.6 360 6 3 7.6 4.2 10.8 51.5 0.2 M M
18500 -29.8 -21.6 338 7 4 7.6 4.2 10.5 50.9 -0.1 1137 5.8
18000 -28.7 -19.7 325 10 5 7.8 4.3 10.2 50.3 -0.4 1088 5.5
17500 -27.5 -17.5 328 11 6 8.3 4.6 9.9 49.8 -0.7 1037 5.3
17000 -26.2 -15.2 333 11 6 8.4 4.6 9.6 49.3 -0.9 986 5.0
16500 -25.1 -13.2 341 12 6 6.8 3.7 9.3 48.7 -1.2 937 4.8
16000 -23.6 -10.5 355 14 7 6.8 3.7 8.5 47.4 -1.9 870 4.4
15500 -22.7 -8.9 360 15 8 6.0 3.3 8.0 46.3 -2.4 827 4.2
15000 -21.8 -7.2 005 17 9 6.0 3.3 7.3 45.2 -3.0 785 4.0
14500 -20.8 -5.4 006 18 9 6.4 3.5 6.8 44.2 -3.6 743 3.8
14000 -19.9 -3.8 004 19 10 6.3 3.5 6.2 43.2 -4.1 700 3.6
13500 -18.9 -2.0 004 20 10 7.6 4.2 5.7 42.3 -4.6 655 3.3
13000 -17.7 0.1 004 21 11 7.7 4.2 5.4 41.7 -4.9 606 3.1
12500 -16.7 1.9 005 22 11 6.7 3.7 5.0 41.0 -5.3 559 2.8
12000 -15.7 3.7 008 24 13 6.8 3.7 4.5 40.1 -5.9 515 2.6
11500 -14.8 5.4 010 26 14 5.8 3.2 3.9 39.1 -6.4 473 2.4
11000 -14.0 6.8 011 27 14 5.7 3.1 3.3 37.9 -7.1 433 2.2
10500 -13.0 8.6 011 28 14 6.9 3.8 2.7 36.9 -7.7 391 2.0
10250 -12.5 9.5 010 28 14 6.8 3.7 2.5 36.5 -8.0 369 1.9
10000 -12.0 10.4 009 28 15 6.8 3.7 2.3 36.1 -8.2 346 1.8
9750 -11.5 11.3 008 29 15 7.6 4.2 2.1 35.7 -8.4 323 1.6
9500 -10.9 12.4 008 29 15 8.3 4.6 1.9 35.5 -8.6 298 1.5
9250 -10.3 13.5 007 29 15 8.1 4.4 1.8 35.2 -8.7 272 1.4
9000 -9.7 14.5 006 30 15 8.4 4.6 1.7 35.0 -8.9 247 1.3
8750 -9.1 15.6 006 30 15 8.9 4.9 1.6 34.9 -9.0 220 1.1
8500 -8.4 16.9 006 30 16 9.1 5.0 1.5 34.8 -9.1 193 1.0
8250 -7.7 18.1 007 31 16 9.1 5.0 1.5 34.7 -9.2 165 0.8
8000 -7.0 19.4 007 31 16 8.9 4.9 1.4 34.6 -9.2 138 0.7
7750 -6.4 20.5 008 30 16 8.8 4.8 1.4 34.4 -9.3 111 0.6
7500 -5.7 21.7 009 30 15 8.9 4.9 1.3 34.3 -9.4 84 0.4
7250 -5.1 22.8 010 29 15 8.7 4.8 1.2 34.2 -9.5 57 0.3
7000 -4.5 23.9 010 28 14 8.3 4.6 1.1 34.0 -9.7 30 0.2
6750 -3.8 25.2 010 26 13 8.2 4.5 1.0 33.8 -9.8 5 0.0
6500 -3.2 26.2 010 25 13 8.2 4.5 0.9 33.6 -9.9 M M
6250 -2.6 27.3 010 23 12 7.7 4.2 0.8 33.4 -10.1 M M
6000 -2.1 28.2 009 20 10 7.4 4.1 0.6 33.1 -10.3 M M
5750 -1.5 29.3 008 18 9 7.5 4.1 0.4 32.8 -10.5 M M
5500 -1.0 30.2 007 15 8 7.4 4.0 0.3 32.5 -10.7 M M
* * * * * * Numerical weather prediction model forecast data valid * * * * * *
03/20/2012 at 0900 MDT | 03/20/2012 at 1200 MDT
|
K index... +3.5 | K index... +1.8
|
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 -54.3 -65.7 084 6 3 2.0 1.1 | -54.6 -66.3 105 8 4 2.0 1.1
45000 -51.2 -60.2 100 3 2 2.0 1.1 | -51.4 -60.5 104 9 5 1.9 1.1
40000 -49.0 -56.2 173 4 2 1.5 0.8 | -50.3 -58.5 029 12 6 0.7 0.4
38000 -48.2 -54.8 177 7 4 1.1 0.6 | -49.7 -57.5 022 12 6 1.6 0.9
36000 -47.5 -53.5 166 12 6 1.1 0.6 | -48.8 -55.8 059 5 2 1.6 0.9
34000 -46.8 -52.2 161 18 9 1.0 0.6 | -47.8 -54.0 153 7 4 1.2 0.7
32000 -44.8 -48.6 166 25 13 3.9 2.2 | -44.6 -48.3 167 16 8 5.3 2.9
30000 -42.1 -43.8 169 34 17 3.9 2.1 | -41.4 -42.5 170 23 12 5.2 2.8
29000 -40.9 -41.6 172 34 18 4.4 2.4 | -39.9 -39.8 167 19 10 4.9 2.7
28000 -39.5 -39.1 174 34 17 4.4 2.4 | -38.5 -37.3 162 14 7 4.9 2.7
27000 -38.2 -36.8 177 33 17 4.4 2.4 | -37.0 -34.6 150 9 5 4.9 2.7
26000 -37.2 -35.0 179 31 16 -0.3 -0.2 | -35.9 -32.6 116 5 3 1.4 0.8
25000 -37.2 -35.0 177 22 11 0.2 0.1 | -35.4 -31.7 064 7 4 1.6 0.9
24000 -37.1 -34.8 172 13 7 0.2 0.1 | -35.0 -31.0 041 11 6 1.6 0.9
23000 -36.8 -34.2 150 6 3 4.0 2.2 | -34.4 -29.9 035 15 8 2.4 1.3
22000 -35.6 -32.1 085 7 4 4.2 2.3 | -33.7 -28.7 038 16 8 2.4 1.3
21000 -34.3 -29.7 061 13 7 4.4 2.4 | -33.0 -27.4 041 16 8 2.5 1.4
20000 -32.6 -26.7 047 17 9 7.8 4.3 | -31.5 -24.7 042 19 10 7.3 4.0
19500 -31.4 -24.5 038 18 9 7.8 4.3 | -30.4 -22.7 041 21 11 7.5 4.1
19000 -30.2 -22.4 030 19 10 7.8 4.3 | -29.3 -20.7 041 23 12 7.5 4.1
18500 -29.1 -20.4 022 20 10 7.8 4.3 | -28.2 -18.8 041 25 13 7.5 4.1
18000 -27.9 -18.2 016 22 11 8.1 4.5 | -27.1 -16.8 040 27 14 8.3 4.6
17500 -26.6 -15.9 015 22 12 8.6 4.7 | -25.0 -13.0 040 27 14 9.1 5.0
17000 -25.3 -13.5 015 23 12 8.8 4.8 | -23.7 -10.7 040 27 14 7.7 4.2
16500 -23.8 -10.8 019 23 12 6.4 3.5 | -22.6 -8.7 042 26 14 7.3 4.0
16000 -22.8 -9.0 023 23 12 6.4 3.5 | -21.6 -6.9 044 26 13 7.4 4.1
15500 -21.8 -7.2 025 23 12 6.9 3.8 | -20.5 -4.9 045 25 13 7.6 4.2
15000 -20.8 -5.4 025 23 12 6.9 3.8 | -19.3 -2.7 047 24 12 7.6 4.2
14500 -19.8 -3.6 023 22 11 6.4 3.5 | -18.3 -0.9 046 23 12 6.8 3.7
14000 -18.9 -2.0 020 22 11 6.8 3.7 | -17.2 1.0 043 23 12 6.9 3.8
13500 -18.1 -0.6 018 22 11 3.9 2.1 | -16.3 2.7 041 22 11 5.3 2.9
13000 -17.5 0.5 017 21 11 4.2 2.3 | -15.5 4.1 038 22 11 5.5 3.0
12500 -16.9 1.6 018 22 11 4.0 2.2 | -14.8 5.4 034 21 11 3.8 2.1
12000 -16.3 2.7 021 22 11 3.8 2.1 | -14.3 6.3 030 20 10 4.0 2.2
11500 -15.5 4.1 023 22 12 6.5 3.6 | -13.6 7.5 023 20 10 4.6 2.5
11000 -14.6 5.7 023 22 12 6.2 3.4 | -13.0 8.6 015 20 10 4.6 2.5
10500 -13.5 7.7 023 23 12 8.7 4.8 | -12.2 10.0 007 19 10 6.4 3.5
10250 -12.8 9.0 023 23 12 8.4 4.6 | -11.7 10.9 003 19 10 6.0 3.3
10000 -12.2 10.0 022 24 12 8.4 4.6 | -11.2 11.8 358 18 10 6.8 3.7
9750 -11.6 11.1 021 24 13 7.9 4.3 | -10.7 12.7 356 18 9 8.2 4.5
9500 -11.0 12.2 020 25 13 7.7 4.2 | -10.1 13.8 356 18 9 8.6 4.7
9250 -10.5 13.1 019 25 13 7.6 4.2 | -9.4 15.1 355 18 9 8.3 4.6
9000 -9.9 14.2 018 26 13 8.3 4.5 | -8.8 16.2 354 17 9 9.1 5.0
8750 -9.2 15.4 016 26 13 9.1 5.0 | -8.1 17.4 354 17 9 9.9 5.5
8500 -8.6 16.5 014 26 13 9.1 5.0 | -7.3 18.9 353 17 9 9.7 5.3
8250 -7.9 17.8 013 25 13 9.0 5.0 | -6.6 20.1 353 17 9 9.9 5.4
8000 -7.2 19.0 011 25 13 8.7 4.7 | -5.9 21.4 353 17 9 10.1 5.5
7750 -6.6 20.1 010 24 13 8.4 4.6 | -5.1 22.8 352 17 9 10.1 5.6
7500 -6.0 21.2 009 24 12 8.6 4.7 | -4.3 24.3 352 17 9 10.1 5.5
7250 -5.4 22.3 008 23 12 8.1 4.5 | -3.6 25.5 351 17 9 10.2 5.6
7000 -4.8 23.4 006 21 11 7.8 4.3 | -2.8 27.0 351 16 8 10.3 5.7
6750 -4.2 24.4 005 19 10 7.6 4.2 | -2.1 28.2 350 16 8 10.3 5.6
6500 -3.7 25.3 003 17 9 8.4 4.6 | -1.3 29.7 350 16 8 10.4 5.7
6250 -3.0 26.6 001 15 8 10.2 5.6 | -0.5 31.1 350 16 8 10.9 6.0
6000 -2.2 28.0 360 14 7 10.3 5.6 | 0.3 32.5 349 15 8 10.1 5.6
5750 -1.4 29.5 359 13 7 11.4 6.3 | 1.1 34.0 348 15 8 13.0 7.2
5500 -0.4 31.3 358 12 6 17.7 9.7 | 2.5 36.5 348 14 7 24.5 13.4
03/20/2012 at 1500 MDT | 03/20/2012 at 1800 MDT
|
K index... +0.7 | K index... -3.7
|
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 -55.8 -68.4 111 5 3 1.8 1.0 | -56.8 -70.2 034 2 1 1.6 0.9
45000 -53.1 -63.6 079 5 2 1.9 1.0 | -54.5 -66.1 355 12 6 1.9 1.1
40000 -49.7 -57.5 027 23 12 2.3 1.3 | -50.3 -58.5 032 29 15 2.8 1.5
38000 -48.6 -55.5 023 29 15 1.1 0.6 | -49.2 -56.6 030 39 20 0.5 0.3
36000 -47.9 -54.2 015 32 16 1.1 0.6 | -48.8 -55.8 020 56 29 0.6 0.3
34000 -47.2 -53.0 007 35 18 3.0 1.7 | -48.3 -54.9 015 71 37 4.4 2.4
32000 -44.4 -47.9 006 27 14 4.6 2.5 | -45.0 -49.0 014 76 39 5.6 3.0
30000 -41.6 -42.9 004 19 10 4.9 2.7 | -41.6 -42.9 013 80 41 5.6 3.1
29000 -40.0 -40.0 012 18 9 5.3 2.9 | -39.9 -39.8 013 70 36 5.7 3.1
28000 -38.4 -37.1 021 17 9 5.3 2.9 | -38.2 -36.8 012 60 31 5.7 3.1
27000 -36.9 -34.4 031 16 8 5.2 2.9 | -36.5 -33.7 012 50 26 5.7 3.1
26000 -35.6 -32.1 040 16 8 2.8 1.5 | -35.1 -31.2 013 41 21 3.8 2.1
25000 -34.7 -30.5 049 15 8 2.8 1.5 | -34.0 -29.2 015 33 17 3.8 2.1
24000 -33.9 -29.0 058 15 8 2.8 1.5 | -32.8 -27.0 020 25 13 3.8 2.1
23000 -33.0 -27.4 060 15 8 2.9 1.6 | -31.6 -24.9 027 19 10 4.7 2.6
22000 -32.2 -26.0 049 17 9 2.9 1.6 | -30.2 -22.4 034 16 8 4.7 2.6
21000 -31.3 -24.3 039 19 10 2.9 1.6 | -28.7 -19.7 044 14 7 4.7 2.6
20000 -29.8 -21.6 035 19 10 6.7 3.7 | -27.2 -17.0 049 13 7 5.5 3.0
19500 -28.8 -19.8 036 19 10 6.8 3.7 | -26.3 -15.3 049 13 7 5.5 3.0
19000 -27.7 -17.9 036 19 10 6.8 3.8 | -25.1 -13.2 049 14 7 5.6 3.1
18500 -26.2 -15.2 036 19 10 6.9 3.8 | -24.3 -11.7 049 14 7 5.9 3.2
18000 -25.1 -13.2 036 19 10 8.3 4.5 | -23.2 -9.8 044 15 8 7.5 4.1
17500 -23.8 -10.8 036 20 11 8.1 4.5 | -22.1 -7.8 039 16 8 7.5 4.1
17000 -22.6 -8.7 037 21 11 8.0 4.4 | -21.1 -6.0 037 17 9 6.6 3.6
16500 -21.4 -6.5 038 21 11 8.0 4.4 | -20.1 -4.2 037 17 9 6.6 3.6
16000 -20.2 -4.4 039 21 11 7.9 4.3 | -19.1 -2.4 039 16 8 6.5 3.6
15500 -19.1 -2.4 040 20 10 7.8 4.3 | -18.1 -0.6 042 15 8 6.6 3.6
15000 -17.9 -0.2 040 18 9 7.7 4.2 | -17.2 1.0 046 14 7 6.7 3.7
14500 -16.9 1.6 040 17 9 7.2 3.9 | -16.1 3.0 045 13 7 7.0 3.9
14000 -15.8 3.6 040 16 8 7.2 3.9 | -15.1 4.8 044 12 6 7.1 3.9
13500 -14.8 5.4 039 15 8 6.5 3.6 | -14.1 6.6 039 11 6 7.3 4.0
13000 -13.8 7.2 039 14 7 6.7 3.7 | -13.0 8.6 033 10 5 7.1 3.9
12500 -13.0 8.6 037 14 7 4.9 2.7 | -12.2 10.0 025 11 5 4.8 2.6
12000 -12.2 10.0 034 14 7 5.1 2.8 | -11.4 11.5 015 11 6 5.1 2.8
11500 -11.4 11.5 024 14 7 5.4 3.0 | -10.5 13.1 010 12 6 7.3 4.0
11000 -10.6 12.9 009 15 8 5.5 3.0 | -9.4 15.1 006 12 6 7.4 4.0
10500 -9.6 14.7 002 16 8 7.8 4.3 | -8.1 17.4 006 12 6 8.9 4.9
10250 -9.0 15.8 001 15 8 7.5 4.1 | -7.5 18.5 007 12 6 8.8 4.8
10000 -8.4 16.9 360 15 8 7.9 4.3 | -6.8 19.8 008 12 6 8.9 4.9
9750 -7.8 18.0 359 15 8 8.5 4.6 | -6.2 20.8 008 11 6 8.9 4.9
9500 -7.2 19.0 359 15 8 8.7 4.8 | -5.5 22.1 009 11 6 8.9 4.9
9250 -6.6 20.1 359 14 7 8.5 4.7 | -4.8 23.4 009 11 6 8.8 4.8
9000 -5.9 21.4 359 14 7 9.1 5.0 | -4.2 24.4 009 11 6 9.2 5.0
8750 -5.2 22.6 359 14 7 9.9 5.4 | -3.5 25.7 009 11 6 9.5 5.2
8500 -4.5 23.9 359 14 7 9.8 5.4 | -2.8 27.0 009 11 5 9.4 5.1
8250 -3.7 25.3 359 14 7 9.8 5.4 | -2.1 28.2 008 10 5 9.5 5.2
8000 -3.0 26.6 359 13 7 9.9 5.4 | -1.4 29.5 008 10 5 9.6 5.3
7750 -2.3 27.9 359 13 7 9.9 5.4 | -0.6 30.9 007 10 5 9.7 5.3
7500 -1.5 29.3 358 13 7 9.9 5.4 | 0.1 32.2 006 10 5 9.7 5.3
7250 -0.8 30.6 358 13 7 10.0 5.5 | 0.8 33.4 005 10 5 9.7 5.3
7000 -0.0 32.0 358 13 7 10.1 5.5 | 1.5 34.7 005 10 5 9.8 5.4
6750 0.7 33.3 358 13 7 10.0 5.5 | 2.3 36.1 004 10 5 9.7 5.3
6500 1.5 34.7 357 13 7 10.2 5.6 | 3.0 37.4 003 9 5 9.9 5.4
6250 2.3 36.1 357 13 6 10.8 5.9 | 3.8 38.8 002 9 5 10.2 5.6
6000 3.1 37.6 356 12 6 10.7 5.9 | 4.5 40.1 001 9 5 10.2 5.6
5750 3.9 39.0 356 12 6 11.6 6.4 | 5.3 41.5 360 9 5 10.7 5.9
5500 5.0 41.0 356 11 6 20.7 11.3 | 6.2 43.2 360 8 4 14.1 7.7
________________________________________________________________________________
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