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

Station:

KOAK

Date/Time:

23 SEP 2017

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 Sat 50 50 NE 5 1106 2000 0 Blue 0
6 AM Sat 49 49 NE 5 1106 2000 0 Blue 0
7 AM Sat 49 49 NE 5 1106 2000 0 Blue 0
8 AM Sat 51 51 NE 5 1106 2000 0 Blue 0
9 AM Sat 55 56 NE 5 1106 2000 0 Blue 0
10 AM Sat 61 64 NE 5 3988 2255 255 Blue 4
11 AM Sat 66 70 W 6 7685 5889 3889 White 10
12 Noon Sat 70 75 W 6 8721 8668 6668 White 15
1 PM Sat 73 79 W 6 9539 9539 7539 White 19
2 PM Sat 75 80 W 6 9742 9742 7742 White 20
3 PM Sat 76 80 W 6 9742 9742 7742 White 20
4 PM Sat 77 80 W 6 9742 9742 7742 White 20
5 PM Sat 76 77 S 7 9132 9132 7132 White 17
6 PM Sat 73 73 S 7 8308 7352 5352 White 13
7 PM Sat 69 69 S 7 6948 4459 2459 Blue 9
8 PM Sat 65 65 NW 6 4234 2723 723 Blue 5
9 PM Sat 63 63 NW 6 3619 2000 0 Blue 3
10 PM Sat 61 61 NW 6 2268 2000 0 Blue 1
11 PM Sat 59 59 NE 7 1552 2000 0 Blue 0
12 Midnight Sun 58 58 NE 7 1190 2000 0 Blue 0
1 AM Sun 57 57 NE 7 1106 2000 0 Blue 0
2 AM Sun 56 56 NE 7 1106 2000 0 Blue 0
3 AM Sun 55 55 NE 7 1106 2000 0 Blue 0
4 AM Sun 53 53 NE 7 1106 2000 0 Blue 0
5 AM Sun 52 52 NE 6 1106 2000 0 Blue 0
6 AM Sun 52 52 NE 6 1106 2000 0 Blue 0
7 AM Sun 53 53 NE 6 1106 2000 0 Blue 0
8 AM Sun 56 56 NE 6 1106 2000 0 Blue 0
9 AM Sun 61 62 NE 6 2731 2000 0 Blue 2
10 AM Sun 66 69 NE 6 6948 4459 2459 Blue 9
11 AM Sun 72 76 SW 5 8926 8926 6926 White 16
12 Noon Sun 75 80 SW 5 9742 9742 7742 White 20
1 PM Sun 77 83 SW 5 10370 10370 8370 White 22
2 PM Sun 78 83 NW 7 10370 10370 8370 White 22
3 PM Sun 79 83 NW 7 10370 10370 8370 White 22
4 PM Sun 80 83 NW 7 10370 10370 8370 White 22
5 PM Sun 79 80 NW 5 9742 9742 7742 White 20
6 PM Sun 76 76 NW 5 8926 8926 6926 White 16
7 PM Sun 71 71 NW 5 7892 6323 4323 White 11
8 PM Sun 67 67 NW 5 5953 3967 1967 Blue 7
9 PM Sun 63 63 NW 5 3619 2000 0 Blue 3
10 PM Sun 60 60 NW 5 1911 2000 0 Blue 0
11 PM Sun 58 58 NE 5 1190 2000 0 Blue 0
12 Midnight Mon 57 57 NE 5 1106 2000 0 Blue 0
1 AM Mon 56 56 NE 5 1106 2000 0 Blue 0
2 AM Mon 55 55 NE 5 1106 2000 0 Blue 0
3 AM Mon 54 54 NE 5 1106 2000 0 Blue 0
4 AM Mon 53 53 NE 5 1106 2000 0 Blue 0
5 AM Mon 52 52 NE 6 1106 2000 0 Blue 0
6 AM Mon 52 52 NE 6 1106 2000 0 Blue 0
7 AM Mon 53 53 NE 6 1106 2000 0 Blue 0
8 AM Mon 56 56 NE 6 1106 2000 0 Blue 0
9 AM Mon 61 62 NE 6 2731 2000 0 Blue 2
10 AM Mon 67 69 NE 6 6948 4459 2459 Blue 9
11 AM Mon 73 77 SW 3 9132 9132 7132 White 17
12 Noon Mon 77 82 SW 3 10169 10169 8169 White 21
1 PM Mon 79 84 SW 3 10570 10570 8570 White 23
2 PM Mon 81 86 SW 3 10970 10970 8970 White 25
3 PM Mon 82 86 SW 3 10970 10970 8970 White 25
4 PM Mon 83 85 SW 3 10770 10770 8770 White 24
5 PM Mon 82 83 NW 5 10370 10370 8370 White 22
6 PM Mon 79 79 NW 5 9539 9539 7539 White 19
7 PM Mon 74 74 NW 5 8514 8037 6037 White 14
8 PM Mon 70 70 NW 5 7685 5889 3889 White 10
9 PM Mon 66 66 NW 5 4486 3550 1550 Blue 6
10 PM Mon 64 64 NW 5 3988 2255 255 Blue 4
11 PM Mon 62 62 NE 5 2731 2000 0 Blue 2
12 Midnight Tue 60 60 NE 5 1911 2000 0 Blue 0
1 AM Tue 58 58 NE 5 1190 2000 0 Blue 0
2 AM Tue 57 57 NE 5 1106 2000 0 Blue 0
3 AM Tue 57 57 NE 5 1106 2000 0 Blue 0
4 AM Tue 56 56 NE 5 1106 2000 0 Blue 0
5 AM Tue 56 56 E 6 1106 2000 0 Blue 0
6 AM Tue 56 56 E 6 1106 2000 0 Blue 0
7 AM Tue 57 57 E 6 1106 2000 0 Blue 0
8 AM Tue 59 59 E 6 1552 2000 0 Blue 0
9 AM Tue 65 66 E 6 4486 3550 1550 Blue 6
10 AM Tue 71 74 E 6 8514 8037 6037 White 14
11 AM Tue 77 81 SW 3 9968 9968 7968 White 20
12 Noon Tue 80 85 SW 3 10770 10770 8770 White 24
1 PM Tue 82 88 SW 3 11366 11366 9366 White 27
2 PM Tue 83 88 SW 3 11366 11366 9366 White 27
3 PM Tue 85 89 SW 3 11563 11563 9563 White 28
4 PM Tue 86 89 SW 3 11563 11563 9563 White 28
5 PM Tue 85 86 NW 5 10970 10970 8970 White 25
6 PM Tue 81 81 NW 5 9968 9968 7968 White 20
7 PM Tue 76 76 NW 5 8926 8926 6926 White 16
8 PM Tue 71 71 NW 5 7892 6323 4323 White 11
9 PM Tue 68 68 NW 5 6469 4209 2209 Blue 8
10 PM Tue 66 66 NW 5 4486 3550 1550 Blue 6
11 PM Tue 65 65 NE 3 4234 2723 723 Blue 5
12 Midnight Wed 64 64 NE 3 3988 2255 255 Blue 4
1 AM Wed 63 63 NE 3 3619 2000 0 Blue 3
2 AM Wed 62 62 NE 3 2731 2000 0 Blue 2
3 AM Wed 61 61 NE 3 2268 2000 0 Blue 1
4 AM Wed 59 59 NE 3 1552 2000 0 Blue 0
5 AM Wed 58 58 E 5 1190 2000 0 Blue 0
6 AM Wed 58 58 E 5 1190 2000 0 Blue 0
7 AM Wed 59 59 E 5 1552 2000 0 Blue 0
8 AM Wed 62 62 E 5 2731 2000 0 Blue 2
9 AM Wed 67 68 E 5 6469 4209 2209 Blue 8
10 AM Wed 74 77 E 5 9132 9132 7132 White 17
11 AM Wed 79 83 S 3 10370 10370 8370 White 22
12 Noon Wed 83 88 S 3 11366 11366 9366 White 27
1 PM Wed 85 91 S 3 11956 11956 9956 White 30
2 PM Wed 86 91 S 3 11956 11956 9956 White 30
3 PM Wed 88 92 S 3 12152 12152 10152 White 31
4 PM Wed 89 91 S 3 11956 11956 9956 White 30
5 PM Wed 88 89 NW 5 11563 11563 9563 White 28
6 PM Wed 84 84 NW 5 10570 10570 8570 White 23
7 PM Wed 79 79 NW 5 9539 9539 7539 White 19
8 PM Wed 73 73 NW 5 8308 7352 5352 White 13
9 PM Wed 70 70 NW 5 7685 5889 3889 White 10
10 PM Wed 68 68 NW 5 6469 4209 2209 Blue 8
11 PM Wed 67 67 NE 5 5953 3967 1967 Blue 7
12 Midnight Thu 65 65 NE 5 4234 2723 723 Blue 5
1 AM Thu 64 64 NE 5 3988 2255 255 Blue 4
2 AM Thu 63 63 NE 5 3619 2000 0 Blue 3
3 AM Thu 63 63 NE 5 3619 2000 0 Blue 3
4 AM Thu 62 62 NE 5 2731 2000 0 Blue 2
5 AM Thu 61 61 NE 5 2268 2000 0 Blue 1
6 AM Thu 60 60 NE 5 1911 2000 0 Blue 0
7 AM Thu 60 60 NE 5 1911 2000 0 Blue 0
8 AM Thu 62 62 NE 5 2731 2000 0 Blue 2
9 AM Thu 68 69 NE 5 6948 4459 2459 Blue 9
10 AM Thu 75 78 NE 5 9335 9335 7335 White 18
11 AM Thu 82 86 SW 3 10970 10970 8970 White 25
12 Noon Thu 86 91 SW 3 11956 11956 9956 White 30
1 PM Thu 88 93 SW 3 12348 12348 10348 White 32
2 PM Thu 89 94 SW 3 12543 12543 10543 White 33
3 PM Thu 90 94 SW 3 12543 12543 10543 White 33
4 PM Thu 91 93 SW 3 12348 12348 10348 White 32
5 PM Thu 90 91 NW 6 11956 11956 9956 White 30
6 PM Thu 87 87 NW 6 11168 11168 9168 White 26
7 PM Thu 82 82 NW 6 10169 10169 8169 White 21
8 PM Thu 77 77 NW 6 9132 9132 7132 White 17
9 PM Thu 73 73 NW 6 8308 7352 5352 White 13
10 PM Thu 71 71 NW 6 7892 6323 4323 White 11
11 PM Thu 69 69 E 5 6948 4459 2459 Blue 9
12 Midnight Fri 68 68 E 5 6469 4209 2209 Blue 8
1 AM Fri 66 66 E 5 4486 3550 1550 Blue 6
2 AM Fri 65 65 E 5 4234 2723 723 Blue 5
3 AM Fri 64 64 E 5 3988 2255 255 Blue 4
4 AM Fri 63 63 E 5 3619 2000 0 Blue 3

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