Detailed Predictions for: Lake McClure
Launch Lat, Long, Altitude (f): 37.3803, -120.0769, 2000
LZ Altitude (f): 500
Sounding

Station:

KOAK

Date/Time:

12 MAY 2021

Temp/Wind data from:

NOAA Digital Forecast

Site Forecasts
Time
(Local)
High
Temp

Puddle
Temp

Wind
(mph)
Wind
Gust
Thermal
Ceiling

(ft)
Soaring
Ceiling

(ft)
Above
Launch

(ft)
Thermal
Type
Thermal
Index

(F)
12 Midnight Wed 72 72 N 4 5 1563 2000 0 Blue 14
1 AM Wed 67 67 NNW 2 2 1388 2000 0 Blue 9
2 AM Wed 68 68 NNE 3 3 1406 2000 0 Blue 10
3 AM Wed 67 67 NE 4 5 1388 2000 0 Blue 9
4 AM Wed 65 65 ENE 5 5 1352 2000 0 Blue 7
5 AM Wed 64 64 ENE 4 5 1334 2000 0 Blue 6
6 AM Wed 63 63 ENE 4 5 1316 2000 0 Blue 5
7 AM Wed 65 65 ENE 4 5 1352 2000 0 Blue 7
8 AM Wed 73 74 E 3 5 1660 2000 0 Blue 16
9 AM Wed 79 82 SSE 4 6 3294 2335 335 Blue 24
10 AM Wed 81 86 S 5 9 5652 3597 1597 Blue 28
11 AM Wed 84 91 SSW 5 10 8693 6157 4157 Blue 33
12 Noon Wed 86 94 SW 5 11 9481 8569 6569 Blue 36
1 PM Wed 88 96 WSW 5 11 11950 9276 7276 White 38
2 PM Wed 90 98 WSW 5 12 12352 10005 8005 White 40
3 PM Wed 90 96 W 5 13 11950 9276 7276 White 38
4 PM Wed 91 95 W 5 13 10212 9073 7073 Blue 37
5 PM Wed 91 93 W 5 12 9302 8231 6231 Blue 35
6 PM Wed 90 91 WNW 5 11 8693 6157 4157 Blue 33
7 PM Wed 87 87 NW 5 10 5927 3918 1918 Blue 29
8 PM Wed 82 82 NNW 3 6 3294 2335 335 Blue 24
9 PM Wed 77 77 NNW 4 5 1918 2000 0 Blue 19
10 PM Wed 74 74 N 4 6 1660 2000 0 Blue 16
11 PM Wed 72 72 N 4 5 1563 2000 0 Blue 14
12 Midnight Thu 70 70 N 4 5 1486 2000 0 Blue 12
1 AM Thu 68 68 NNE 4 5 1406 2000 0 Blue 10
2 AM Thu 67 67 NNE 4 5 1388 2000 0 Blue 9
3 AM Thu 66 66 NNE 4 5 1370 2000 0 Blue 8
4 AM Thu 65 65 NNE 4 5 1352 2000 0 Blue 7
5 AM Thu 64 64 NE 3 4 1334 2000 0 Blue 6
6 AM Thu 64 64 NNE 4 4 1334 2000 0 Blue 6
7 AM Thu 66 66 NE 3 4 1370 2000 0 Blue 8
8 AM Thu 73 74 SSW 3 4 1660 2000 0 Blue 16
9 AM Thu 77 80 WSW 4 5 2631 2000 0 Blue 22
10 AM Thu 81 86 WSW 5 8 5652 3597 1597 Blue 28
11 AM Thu 83 89 W 6 12 7460 5613 3613 Blue 31
12 Noon Thu 86 94 W 6 12 9481 8569 6569 Blue 36
1 PM Thu 88 96 W 6 12 11950 9276 7276 White 38
2 PM Thu 89 96 W 8 16 11950 9276 7276 White 38
3 PM Thu 90 96 W 8 16 11950 9276 7276 White 38
4 PM Thu 91 95 W 8 16 10212 9073 7073 Blue 37
5 PM Thu 90 92 WNW 9 16 9203 7243 5243 Blue 34
6 PM Thu 88 89 WNW 9 16 7460 5613 3613 Blue 31
7 PM Thu 85 85 WNW 9 16 5375 3273 1273 Blue 27
8 PM Thu 81 81 NW 5 9 2964 2057 57 Blue 23
9 PM Thu 77 77 NW 5 9 1918 2000 0 Blue 19
10 PM Thu 73 73 NW 5 9 1601 2000 0 Blue 15
11 PM Thu 70 70 N 4 5 1486 2000 0 Blue 12
12 Midnight Fri 68 68 N 4 5 1406 2000 0 Blue 10
1 AM Fri 67 67 N 4 5 1388 2000 0 Blue 9
2 AM Fri 66 66 NNE 4 5 1370 2000 0 Blue 8
3 AM Fri 64 64 NNE 4 5 1334 2000 0 Blue 6
4 AM Fri 63 63 NNE 4 5 1316 2000 0 Blue 5
5 AM Fri 63 63 NE 3 4 1316 2000 0 Blue 5
6 AM Fri 64 64 NE 3 4 1334 2000 0 Blue 6
7 AM Fri 67 67 NE 3 4 1388 2000 0 Blue 9
8 AM Fri 70 71 SSW 3 4 1526 2000 0 Blue 13
9 AM Fri 74 77 SSW 3 4 1918 2000 0 Blue 19
10 AM Fri 78 83 SSW 3 4 3622 2616 616 Blue 25
11 AM Fri 81 88 SW 5 10 6262 5339 3339 Blue 30
12 Noon Fri 83 91 SW 5 10 8693 6157 4157 Blue 33
1 PM Fri 85 93 SW 5 10 9302 8231 6231 Blue 35
2 PM Fri 86 93 WSW 6 14 9302 8231 6231 Blue 35
3 PM Fri 88 94 WSW 6 14 9481 8569 6569 Blue 36
4 PM Fri 89 93 WSW 6 14 9302 8231 6231 Blue 35
5 PM Fri 88 90 W 8 14 8303 5886 3886 Blue 32
6 PM Fri 85 86 W 8 14 5652 3597 1597 Blue 28
7 PM Fri 81 81 W 8 14 2964 2057 57 Blue 23
8 PM Fri 76 76 W 4 11 1832 2000 0 Blue 18
9 PM Fri 72 72 W 4 11 1563 2000 0 Blue 14
10 PM Fri 68 68 W 4 11 1406 2000 0 Blue 10
11 PM Fri 65 65 NW 3 6 1352 2000 0 Blue 7
12 Midnight Sat 63 63 NW 3 6 1316 2000 0 Blue 5
1 AM Sat 61 61 NW 3 6 1279 2000 0 Blue 3
2 AM Sat 60 60 NNW 3 5 1261 2000 0 Blue 2
3 AM Sat 58 58 NNW 3 5 1220 2000 0 Blue 0
4 AM Sat 56 56 NNW 3 5 1143 2000 0 Blue 0
5 AM Sat 56 56 NE 2 3 1143 2000 0 Blue 0
6 AM Sat 57 57 NE 2 3 1186 2000 0 Blue 0
7 AM Sat 59 59 NE 2 3 1243 2000 0 Blue 1
8 AM Sat 62 63 SW 4 6 1316 2000 0 Blue 5
9 AM Sat 65 68 SW 4 6 1406 2000 0 Blue 10
10 AM Sat 68 72 SW 4 6 1563 2000 0 Blue 14
11 AM Sat 71 72 SW 5 12 1563 2000 0 Blue 14
12 Noon Sat 73 74 SW 5 12 1660 2000 0 Blue 16
1 PM Sat 75 76 SW 5 12 1832 2000 0 Blue 18
2 PM Sat 76 77 WSW 6 14 1918 2000 0 Blue 19
3 PM Sat 78 79 WSW 6 14 2345 2000 0 Blue 21
4 PM Sat 79 79 WSW 6 14 2345 2000 0 Blue 21
5 PM Sat 79 79 W 5 12 2345 2000 0 Blue 21
6 PM Sat 78 78 W 5 12 2064 2000 0 Blue 20
7 PM Sat 76 76 W 5 12 1832 2000 0 Blue 18
8 PM Sat 73 73 WNW 4 9 1601 2000 0 Blue 15
9 PM Sat 70 70 WNW 4 9 1486 2000 0 Blue 12
10 PM Sat 67 67 WNW 4 9 1388 2000 0 Blue 9
11 PM Sat 65 65 NW 3 6 1352 2000 0 Blue 7
12 Midnight Sun 63 63 NW 3 6 1316 2000 0 Blue 5
1 AM Sun 62 62 NW 3 6 1297 2000 0 Blue 4
2 AM Sun 61 61 NE 2 5 1279 2000 0 Blue 3
3 AM Sun 59 59 NE 2 5 1243 2000 0 Blue 1
4 AM Sun 58 58 NE 2 5 1220 2000 0 Blue 0
5 AM Sun 57 57 E 2 4 1186 2000 0 Blue 0
6 AM Sun 58 58 E 2 4 1220 2000 0 Blue 0
7 AM Sun 60 60 E 2 4 1261 2000 0 Blue 2
8 AM Sun 63 64 S 3 6 1334 2000 0 Blue 6
9 AM Sun 66 69 S 3 6 1440 2000 0 Blue 11
10 AM Sun 69 74 S 3 6 1660 2000 0 Blue 16
11 AM Sun 72 73 SW 5 11 1601 2000 0 Blue 15
12 Noon Sun 74 76 SW 5 11 1832 2000 0 Blue 18
1 PM Sun 76 78 SW 5 11 2064 2000 0 Blue 20
2 PM Sun 78 80 WSW 6 13 2631 2000 0 Blue 22
3 PM Sun 80 81 WSW 6 13 2964 2057 57 Blue 23
4 PM Sun 82 83 WSW 6 13 3622 2616 616 Blue 25
5 PM Sun 82 84 W 6 13 3946 2946 946 Blue 26
6 PM Sun 80 81 W 6 13 2964 2057 57 Blue 23
7 PM Sun 77 77 W 6 13 1918 2000 0 Blue 19
8 PM Sun 74 74 WNW 3 6 1660 2000 0 Blue 16
9 PM Sun 71 71 WNW 3 6 1526 2000 0 Blue 13
10 PM Sun 68 68 WNW 3 6 1406 2000 0 Blue 10
11 PM Sun 66 66 NNW 2 5 1370 2000 0 Blue 8
12 Midnight Mon 64 64 NNW 2 5 1334 2000 0 Blue 6
1 AM Mon 63 63 NNW 2 5 1316 2000 0 Blue 5
2 AM Mon 62 62 N 2 5 1297 2000 0 Blue 4
3 AM Mon 60 60 N 2 5 1261 2000 0 Blue 2
4 AM Mon 59 59 N 2 5 1243 2000 0 Blue 1
5 AM Mon 59 59 NNE 2 3 1243 2000 0 Blue 1
6 AM Mon 60 60 NNE 2 3 1261 2000 0 Blue 2
7 AM Mon 62 62 NNE 2 3 1297 2000 0 Blue 4
8 AM Mon 64 65 SW 2 5 1352 2000 0 Blue 7
9 AM Mon 67 70 SW 2 5 1486 2000 0 Blue 12
10 AM Mon 71 76 SW 2 5 1832 2000 0 Blue 18
11 AM Mon 74 80 WSW 5 11 2631 2000 0 Blue 22
12 Noon Mon 76 83 WSW 5 11 3622 2616 616 Blue 25
1 PM Mon 78 85 WSW 5 11 5375 3273 1273 Blue 27
2 PM Mon 80 87 W 6 14 5927 3918 1918 Blue 29
3 PM Mon 82 88 W 6 14 6262 5339 3339 Blue 30
4 PM Mon 83 87 W 6 14 5927 3918 1918 Blue 29
5 PM Mon 83 85 W 8 14 5375 3273 1273 Blue 27
6 PM Mon 81 82 W 8 14 3294 2335 335 Blue 24
7 PM Mon 78 78 W 8 14 2064 2000 0 Blue 20
8 PM Mon 74 74 WNW 5 11 1660 2000 0 Blue 16
9 PM Mon 71 71 WNW 5 11 1526 2000 0 Blue 13
10 PM Mon 68 68 WNW 5 11 1406 2000 0 Blue 10

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 or WeatherAPI.com website.  Puddle temperatures can exceed this temperature. 

Puddle Temp: This estimate is based on the High Temp and the National Weather Service or WeatherAPI.com 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 or WeatherAPI.com website.

Wind Gust: This estimate is taken from the National Weather Service or WeatherAPI.com 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