Detailed Predictions for: Lake McClure
Launch Altitude (f): 2000
LZ Altitude (f): 500
Sounding

Station:

KOAK

Date/Time:

19 AUG 2018

Temp/Wind data from:

NOAA Digital Forecast

Site Forecasts
Time
(Local)
High
Temp

Puddle
Temp

Wind
(mph)
Thermal
Ceiling

(ft)
Soaring
Ceiling

(ft)
Above
Launch

(ft)
Thermal
Type
Thermal
Index

(F)
5 AM Sun 69 69 N 9 1478 2000 0 Blue 0
6 AM Sun 69 69 N 9 1478 2000 0 Blue 0
7 AM Sun 69 69 N 9 1478 2000 0 Blue 0
8 AM Sun 77 77 NW 5 1704 2000 0 Blue 5
9 AM Sun 84 86 NW 5 2304 2000 0 Blue 14
10 AM Sun 87 91 NW 5 2974 2524 524 Blue 19
11 AM Sun 91 96 W 10 5376 3545 1545 Blue 24
12 Noon Sun 93 100 W 10 6890 5901 3901 Blue 28
1 PM Sun 96 103 W 10 8248 6850 4850 Blue 31
2 PM Sun 98 105 W 10 9152 7684 5684 Blue 33
3 PM Sun 99 105 W 10 9152 7684 5684 Blue 33
4 PM Sun 100 104 W 10 8705 7211 5211 Blue 32
5 PM Sun 99 101 NW 9 7303 6407 4407 Blue 29
6 PM Sun 98 99 NW 9 6667 5296 3296 Blue 27
7 PM Sun 94 94 NW 9 4066 2958 958 Blue 22
8 PM Sun 87 87 NW 7 2417 2076 76 Blue 15
9 PM Sun 82 82 NW 7 1922 2000 0 Blue 10
10 PM Sun 79 79 NW 7 1754 2000 0 Blue 7
11 PM Sun 77 77 N 6 1704 2000 0 Blue 5
12 Midnight Mon 74 74 N 6 1629 2000 0 Blue 2
1 AM Mon 72 72 N 6 1577 2000 0 Blue 0
2 AM Mon 70 70 NE 6 1511 2000 0 Blue 0
3 AM Mon 70 70 NE 6 1511 2000 0 Blue 0
4 AM Mon 70 70 NE 6 1511 2000 0 Blue 0
5 AM Mon 69 69 E 5 1478 2000 0 Blue 0
6 AM Mon 68 68 E 5 1445 2000 0 Blue 0
7 AM Mon 68 68 E 5 1445 2000 0 Blue 0
8 AM Mon 76 76 S 5 1679 2000 0 Blue 4
9 AM Mon 82 84 S 5 2079 2000 0 Blue 12
10 AM Mon 85 89 S 5 2643 2300 300 Blue 17
11 AM Mon 89 95 S 8 4735 3253 1253 Blue 23
12 Noon Mon 91 98 S 8 6444 4664 2664 Blue 26
1 PM Mon 93 101 S 8 7303 6407 4407 Blue 29
2 PM Mon 95 102 SW 8 7781 6629 4629 Blue 30
3 PM Mon 96 102 SW 8 7781 6629 4629 Blue 30
4 PM Mon 97 101 SW 8 7303 6407 4407 Blue 29
5 PM Mon 96 98 W 7 6444 4664 2664 Blue 26
6 PM Mon 95 96 W 7 5376 3545 1545 Blue 24
7 PM Mon 91 91 W 7 2974 2524 524 Blue 19
8 PM Mon 84 84 NW 3 2079 2000 0 Blue 12
9 PM Mon 79 79 NW 3 1754 2000 0 Blue 7
10 PM Mon 76 76 NW 3 1679 2000 0 Blue 4
11 PM Mon 74 74 NE 2 1629 2000 0 Blue 2
12 Midnight Tue 71 71 NE 2 1544 2000 0 Blue 0
1 AM Tue 69 69 NE 2 1478 2000 0 Blue 0
2 AM Tue 67 67 E 3 1413 2000 0 Blue 0
3 AM Tue 67 67 E 3 1413 2000 0 Blue 0
4 AM Tue 67 67 E 3 1413 2000 0 Blue 0
5 AM Tue 66 66 N 1 1380 2000 0 Blue 0
6 AM Tue 65 65 N 1 1347 2000 0 Blue 0
7 AM Tue 65 65 N 1 1347 2000 0 Blue 0
8 AM Tue 73 73 N 1 1605 2000 0 Blue 1
9 AM Tue 79 81 N 1 1860 2000 0 Blue 9
10 AM Tue 82 86 N 1 2304 2000 0 Blue 14
11 AM Tue 86 91 SW 6 2974 2524 524 Blue 19
12 Noon Tue 88 95 SW 6 4735 3253 1253 Blue 23
1 PM Tue 90 97 SW 6 5991 4005 2005 Blue 25
2 PM Tue 92 99 SW 6 6667 5296 3296 Blue 27
3 PM Tue 93 99 SW 6 6667 5296 3296 Blue 27
4 PM Tue 94 98 SW 6 6444 4664 2664 Blue 26
5 PM Tue 93 95 W 3 4735 3253 1253 Blue 23
6 PM Tue 92 93 W 3 3567 2778 778 Blue 21
7 PM Tue 88 88 W 3 2529 2188 188 Blue 16
8 PM Tue 83 83 W 3 1984 2000 0 Blue 11
9 PM Tue 78 78 W 3 1729 2000 0 Blue 6
10 PM Tue 75 75 W 3 1654 2000 0 Blue 3
11 PM Tue 73 73 N 5 1605 2000 0 Blue 1
12 Midnight Wed 70 70 N 5 1511 2000 0 Blue 0
1 AM Wed 68 68 N 5 1445 2000 0 Blue 0
2 AM Wed 67 67 N 5 1413 2000 0 Blue 0
3 AM Wed 67 67 N 5 1413 2000 0 Blue 0
4 AM Wed 67 67 N 5 1413 2000 0 Blue 0
5 AM Wed 66 66 N 2 1380 2000 0 Blue 0
6 AM Wed 65 65 N 2 1347 2000 0 Blue 0
7 AM Wed 65 65 N 2 1347 2000 0 Blue 0
8 AM Wed 73 73 N 2 1605 2000 0 Blue 1
9 AM Wed 79 81 N 2 1860 2000 0 Blue 9
10 AM Wed 82 85 N 2 2192 2000 0 Blue 13
11 AM Wed 86 91 W 6 2974 2524 524 Blue 19
12 Noon Wed 88 95 W 6 4735 3253 1253 Blue 23
1 PM Wed 90 97 W 6 5991 4005 2005 Blue 25
2 PM Wed 92 99 W 6 6667 5296 3296 Blue 27
3 PM Wed 93 99 W 6 6667 5296 3296 Blue 27
4 PM Wed 94 98 W 6 6444 4664 2664 Blue 26
5 PM Wed 93 95 NW 5 4735 3253 1253 Blue 23
6 PM Wed 92 93 NW 5 3567 2778 778 Blue 21
7 PM Wed 88 88 NW 5 2529 2188 188 Blue 16
8 PM Wed 83 83 NW 5 1984 2000 0 Blue 11
9 PM Wed 78 78 NW 5 1729 2000 0 Blue 6
10 PM Wed 75 75 NW 5 1654 2000 0 Blue 3
11 PM Wed 73 73 N 3 1605 2000 0 Blue 1
12 Midnight Thu 70 70 N 3 1511 2000 0 Blue 0
1 AM Thu 68 68 N 3 1445 2000 0 Blue 0
2 AM Thu 67 67 N 3 1413 2000 0 Blue 0
3 AM Thu 67 67 N 3 1413 2000 0 Blue 0
4 AM Thu 67 67 N 3 1413 2000 0 Blue 0
5 AM Thu 66 66 N 2 1380 2000 0 Blue 0
6 AM Thu 65 65 N 2 1347 2000 0 Blue 0
7 AM Thu 65 65 N 2 1347 2000 0 Blue 0
8 AM Thu 73 73 N 2 1605 2000 0 Blue 1
9 AM Thu 80 82 N 2 1922 2000 0 Blue 10
10 AM Thu 83 87 N 2 2417 2076 76 Blue 15
11 AM Thu 86 91 W 7 2974 2524 524 Blue 19
12 Noon Thu 89 96 W 7 5376 3545 1545 Blue 24
1 PM Thu 91 98 W 7 6444 4664 2664 Blue 26
2 PM Thu 93 100 W 7 6890 5901 3901 Blue 28
3 PM Thu 94 100 W 7 6890 5901 3901 Blue 28
4 PM Thu 95 99 W 7 6667 5296 3296 Blue 27
5 PM Thu 94 96 NW 6 5376 3545 1545 Blue 24
6 PM Thu 93 94 NW 6 4066 2958 958 Blue 22
7 PM Thu 89 89 NW 6 2643 2300 300 Blue 17
8 PM Thu 83 83 NW 6 1984 2000 0 Blue 11
9 PM Thu 78 78 NW 6 1729 2000 0 Blue 6
10 PM Thu 76 76 NW 6 1679 2000 0 Blue 4
11 PM Thu 73 73 N 3 1605 2000 0 Blue 1
12 Midnight Fri 70 70 N 3 1511 2000 0 Blue 0
1 AM Fri 68 68 N 3 1445 2000 0 Blue 0
2 AM Fri 67 67 N 3 1413 2000 0 Blue 0
3 AM Fri 67 67 N 3 1413 2000 0 Blue 0
4 AM Fri 67 67 N 3 1413 2000 0 Blue 0
5 AM Fri 66 66 N 2 1380 2000 0 Blue 0
6 AM Fri 65 65 N 2 1347 2000 0 Blue 0
7 AM Fri 65 65 N 2 1347 2000 0 Blue 0
8 AM Fri 73 73 N 2 1605 2000 0 Blue 1
9 AM Fri 79 81 N 2 1860 2000 0 Blue 9
10 AM Fri 82 86 N 2 2304 2000 0 Blue 14
11 AM Fri 86 92 W 8 3272 2637 637 Blue 20
12 Noon Fri 88 95 W 8 4735 3253 1253 Blue 23
1 PM Fri 90 98 W 8 6444 4664 2664 Blue 26
2 PM Fri 92 99 W 8 6667 5296 3296 Blue 27
3 PM Fri 93 99 W 8 6667 5296 3296 Blue 27
4 PM Fri 94 98 W 8 6444 4664 2664 Blue 26
5 PM Fri 93 95 NW 6 4735 3253 1253 Blue 23
6 PM Fri 92 93 NW 6 3567 2778 778 Blue 21
7 PM Fri 88 88 NW 6 2529 2188 188 Blue 16
8 PM Fri 82 82 NW 6 1922 2000 0 Blue 10
9 PM Fri 77 77 NW 6 1704 2000 0 Blue 5
10 PM Fri 75 75 NW 6 1654 2000 0 Blue 3
11 PM Fri 72 72 N 3 1577 2000 0 Blue 0
12 Midnight Sat 69 69 N 3 1478 2000 0 Blue 0
1 AM Sat 67 67 N 3 1413 2000 0 Blue 0
2 AM Sat 66 66 N 3 1380 2000 0 Blue 0
3 AM Sat 66 66 N 3 1380 2000 0 Blue 0
4 AM Sat 66 66 N 3 1380 2000 0 Blue 0

DISCLAIMER: These estimates are intended to assist in daily site selection only.  No warranty is made concerning the accuracy of these estimates.  These estimates cannot be used to determine if conditions are safe for flying.  Conditions should be evaluated at the launch site by experienced pilots before launching.

Sounding: This is the site at which the weather balloon was released.  If the flying site predicted is far from the sounding site, the estimate is not valid.  Also, the sounding is done at 12Z (4AM PST).  If a front comes through, the sounding is no longer valid. The sounding becomes less valid later in the day.

Thermal Ceiling: the lower of the height at which the thermal stops rising and the cloud level.  We can't fly into the clouds, so it doesn't matter how much higher the thermal goes.  Remember that we can't get to the top of the thermal because of our sink rate.  Our upper limit will be lower than the reported ceiling.

Soaring Ceiling: We will stop going up when the thermal is rising just fast enough to offset our sink.  It is estimated that this happens when the temperature difference between the thermal and the surrounding air is about 2 degrees F. This number is an estimate of the maximum altitude we might reach if we start at launch height, and should be more reflective of our chances of soaring than the thermal top. Please let me know how this compares with actually flying, and I will adjust it as necessary.

Above Launch: The difference between how high we might get and how high we start. This estimate does not account for ridge lift.

High Temp: This estimate is taken from the National Weather Service website.  Puddle temperatures can exceed this temperature. 

Puddle Temp: This estimate is based on the High Temp and the National Weather Service estimate of cloudiness, and the angle of the sun.  When the sun is directly overhead on a sunny day, the puddle temp is esimated to be 25 degrees warmer than the high ambient temperature. This estimate now includes a rigorous calculation of the Sun Angle, and accounts for the seasonal differences in zenith and daylight hours.

Wind: This estimate is taken from the National Weather Service website.

Thermal Type: Blue (no cloud formation) or White (Cloud formation)

Thermal Index: This is the maximum difference in temperature between the rising packet of air (the thermal) and the surrounding air.  The difference in temperature is responsible for the buoyancy of the thermal, and larger temperature differences mean faster rising thermals.  A value of about 10 F or greater often means that the conditions are soarable.  Values above 20 could indicate rowdy thermals.

Validity of estimate: Many factors (including strong wind, fronts, cloud shadows, incorrectly predicted temperatures, etc) can affect the validity of the estimates. 

Author: Tad Hurst

Supported By: Alan Crouse ac_soaring@yahoo.com