Detailed Predictions for: Potato Hill
Launch Altitude (f): 3400
LZ Altitude (f): 1700
Sounding

Station:

 KOAK

Date/Time:

 3 SEP 2010

Temp/Wind data from:

NOAA Digital Forecast

Time
(Local)		 High
Temp
Puddle
Temp
Wind
 (mph)		 Thermal
Ceiling
(ft)		 Soaring
Ceiling
(ft)		 Above
Launch
(ft)		 Thermal
Type		 Thermal
Index
(F)
5 AM Fri 65 65 W 5 2605 3400 0 Blue 0
6 AM Fri 66 66 W 5 2605 3400 0 Blue 0
7 AM Fri 68 68 W 5 2605 3400 0 Blue 0
8 AM Fri 72 72 NW 2 2605 3400 0 Blue 0
9 AM Fri 79 80 NW 2 3480 3400 0 Blue 2
10 AM Fri 86 89 NW 2 6409 5067 1667 Blue 11
11 AM Fri 92 97 SE 7 12844 9170 5770 White 19
12 Noon Fri 95 101 SE 7 13669 12344 8944 White 23
1 PM Fri 97 104 SE 7 14284 14284 10884 White 26
2 PM Fri 97 103 SE 10 14080 14080 10680 White 25
3 PM Fri 97 102 SE 10 13875 13158 9758 White 24
4 PM Fri 97 101 SE 10 13669 12344 8944 White 23
5 PM Fri 95 97 SW 10 12844 9170 5770 White 19
6 PM Fri 88 89 SW 10 6409 5067 1667 Blue 11
7 PM Fri 80 80 SW 10 3480 3400 0 Blue 2
8 PM Fri 73 73 W 6 2605 3400 0 Blue 0
9 PM Fri 70 70 W 6 2605 3400 0 Blue 0
10 PM Fri 68 68 W 6 2605 3400 0 Blue 0
11 PM Fri 67 67 W 6 2605 3400 0 Blue 0
12 Midnight Sat 66 66 W 6 2605 3400 0 Blue 0
1 AM Sat 66 66 W 6 2605 3400 0 Blue 0
2 AM Sat 65 65 W 5 2605 3400 0 Blue 0
3 AM Sat 64 64 W 5 2605 3400 0 Blue 0
4 AM Sat 63 63 W 5 2605 3400 0 Blue 0
5 AM Sat 63 63 NW 6 2605 3400 0 Blue 0
6 AM Sat 62 62 NW 6 2605 3400 0 Blue 0
7 AM Sat 62 62 NW 6 2605 3400 0 Blue 0
8 AM Sat 65 65 N 3 2605 3400 0 Blue 0
9 AM Sat 72 73 N 3 2605 3400 0 Blue 0
10 AM Sat 80 83 N 3 4441 3473 73 Blue 5
11 AM Sat 87 91 SW 2 7245 5938 2538 Blue 13
12 Noon Sat 90 96 SW 2 12637 8481 5081 White 18
1 PM Sat 92 98 SW 2 13051 9825 6425 White 20
2 PM Sat 92 98 SW 3 13051 9825 6425 White 20
3 PM Sat 92 97 SW 3 12844 9170 5770 White 19
4 PM Sat 92 96 SW 3 12637 8481 5081 White 18
5 PM Sat 89 91 W 8 7245 5938 2538 Blue 13
6 PM Sat 83 84 W 8 4667 3792 392 Blue 6
7 PM Sat 76 76 W 8 2605 3400 0 Blue 0
8 PM Sat 70 70 W 8 2605 3400 0 Blue 0
9 PM Sat 66 66 W 8 2605 3400 0 Blue 0
10 PM Sat 64 64 W 8 2605 3400 0 Blue 0
11 PM Sat 62 62 NW 7 2605 3400 0 Blue 0
12 Midnight Sun 61 61 NW 7 2605 3400 0 Blue 0
1 AM Sun 61 61 NW 7 2605 3400 0 Blue 0
2 AM Sun 60 60 NW 7 2605 3400 0 Blue 0
3 AM Sun 59 59 NW 7 2605 3400 0 Blue 0
4 AM Sun 58 58 NW 7 2605 3400 0 Blue 0
5 AM Sun 58 58 N 2 2605 3400 0 Blue 0
6 AM Sun 57 57 N 2 2605 3400 0 Blue 0
7 AM Sun 57 57 N 2 2605 3400 0 Blue 0
8 AM Sun 59 59 N 2 2605 3400 0 Blue 0
9 AM Sun 64 65 N 2 2605 3400 0 Blue 0
10 AM Sun 71 74 N 2 2605 3400 0 Blue 0
11 AM Sun 77 81 SE 7 3803 3400 0 Blue 3
12 Noon Sun 80 86 SE 7 5100 4424 1024 Blue 8
1 PM Sun 81 87 SE 7 5544 4658 1258 Blue 9
2 PM Sun 81 87 SE 7 5544 4658 1258 Blue 9
3 PM Sun 81 86 SE 7 5100 4424 1024 Blue 8
4 PM Sun 81 85 SE 7 4819 4110 710 Blue 7
5 PM Sun 79 81 N 13 3803 3400 0 Blue 3
6 PM Sun 75 76 N 13 2605 3400 0 Blue 0
7 PM Sun 69 69 N 13 2605 3400 0 Blue 0
8 PM Sun 63 63 N 13 2605 3400 0 Blue 0
9 PM Sun 60 60 N 13 2605 3400 0 Blue 0
10 PM Sun 57 57 N 13 2605 3400 0 Blue 0
11 PM Sun 56 56 N 8 2605 3400 0 Blue 0
12 Midnight Mon 55 55 N 8 2605 3400 0 Blue 0
1 AM Mon 54 54 N 8 2605 3400 0 Blue 0
2 AM Mon 54 54 N 8 2605 3400 0 Blue 0
3 AM Mon 53 53 N 8 2605 3400 0 Blue 0
4 AM Mon 53 53 N 8 2605 3400 0 Blue 0
5 AM Mon 53 53 N 8 2605 3400 0 Blue 0
6 AM Mon 52 52 N 8 2605 3400 0 Blue 0
7 AM Mon 53 53 N 8 2605 3400 0 Blue 0
8 AM Mon 55 55 N 8 2605 3400 0 Blue 0
9 AM Mon 61 62 N 8 2605 3400 0 Blue 0
10 AM Mon 69 72 N 8 2605 3400 0 Blue 0
11 AM Mon 76 80 N 7 3480 3400 0 Blue 2
12 Noon Mon 80 86 N 7 5100 4424 1024 Blue 8
1 PM Mon 82 88 N 7 5981 4810 1410 Blue 10
2 PM Mon 83 89 N 7 6409 5067 1667 Blue 11
3 PM Mon 83 88 N 7 5981 4810 1410 Blue 10
4 PM Mon 81 85 N 7 4819 4110 710 Blue 7
5 PM Mon 79 81 E 1 3803 3400 0 Blue 3
6 PM Mon 77 78 E 1 2866 3400 0 Blue 0
7 PM Mon 73 73 E 1 2605 3400 0 Blue 0
8 PM Mon 69 69 E 1 2605 3400 0 Blue 0
9 PM Mon 65 65 E 1 2605 3400 0 Blue 0
10 PM Mon 62 62 E 1 2605 3400 0 Blue 0
11 PM Mon 58 58 NW 3 2605 3400 0 Blue 0
12 Midnight Tue 57 57 NW 3 2605 3400 0 Blue 0
1 AM Tue 55 55 NW 3 2605 3400 0 Blue 0
2 AM Tue 55 55 NW 3 2605 3400 0 Blue 0
3 AM Tue 55 55 NW 3 2605 3400 0 Blue 0
4 AM Tue 55 55 NW 3 2605 3400 0 Blue 0
5 AM Tue 56 56 E 2 2605 3400 0 Blue 0
6 AM Tue 58 58 E 2 2605 3400 0 Blue 0
7 AM Tue 61 61 E 2 2605 3400 0 Blue 0
8 AM Tue 64 64 E 2 2605 3400 0 Blue 0
9 AM Tue 67 68 E 2 2605 3400 0 Blue 0
10 AM Tue 70 72 E 2 2605 3400 0 Blue 0
11 AM Tue 72 75 SE 5 2605 3400 0 Blue 0
12 Noon Tue 75 79 SE 5 3155 3400 0 Blue 1
1 PM Tue 76 80 SE 5 3480 3400 0 Blue 2
2 PM Tue 78 82 SE 5 4123 3400 0 Blue 4
3 PM Tue 78 81 SE 5 3803 3400 0 Blue 3
4 PM Tue 78 80 SE 5 3480 3400 0 Blue 2
5 PM Tue 77 78 SW 10 2866 3400 0 Blue 0
6 PM Tue 75 75 SW 10 2605 3400 0 Blue 0
7 PM Tue 71 71 SW 10 2605 3400 0 Blue 0
8 PM Tue 67 67 SW 10 2605 3400 0 Blue 0
9 PM Tue 63 63 SW 10 2605 3400 0 Blue 0
10 PM Tue 59 59 SW 10 2605 3400 0 Blue 0
11 PM Tue 56 56 W 7 2605 3400 0 Blue 0
12 Midnight Wed 54 54 W 7 2605 3400 0 Blue 0
1 AM Wed 52 52 W 7 2605 3400 0 Blue 0
2 AM Wed 52 52 W 7 2605 3400 0 Blue 0
3 AM Wed 52 52 W 7 2605 3400 0 Blue 0
4 AM Wed 52 52 W 7 2605 3400 0 Blue 0
5 AM Wed 53 53 N 3 2605 3400 0 Blue 0
6 AM Wed 54 54 N 3 2605 3400 0 Blue 0
7 AM Wed 55 55 N 3 2605 3400 0 Blue 0
8 AM Wed 57 57 N 3 2605 3400 0 Blue 0
9 AM Wed 60 61 N 3 2605 3400 0 Blue 0
10 AM Wed 62 64 N 3 2605 3400 0 Blue 0
11 AM Wed 64 67 S 1 2605 3400 0 Blue 0
12 Noon Wed 66 70 S 1 2605 3400 0 Blue 0
1 PM Wed 68 72 S 1 2605 3400 0 Blue 0
2 PM Wed 70 74 S 1 2605 3400 0 Blue 0
3 PM Wed 71 74 S 1 2605 3400 0 Blue 0
4 PM Wed 72 74 S 1 2605 3400 0 Blue 0
5 PM Wed 72 73 SW 3 2605 3400 0 Blue 0
6 PM Wed 71 71 SW 3 2605 3400 0 Blue 0
7 PM Wed 69 69 SW 3 2605 3400 0 Blue 0
8 PM Wed 67 67 SW 3 2605 3400 0 Blue 0
9 PM Wed 64 64 SW 3 2605 3400 0 Blue 0
10 PM Wed 62 62 SW 3 2605 3400 0 Blue 0
11 PM Wed 59 59 N 3 2605 3400 0 Blue 0
12 Midnight Thu 57 57 N 3 2605 3400 0 Blue 0
1 AM Thu 56 56 N 3 2605 3400 0 Blue 0
2 AM Thu 54 54 N 3 2605 3400 0 Blue 0
3 AM Thu 53 53 N 3 2605 3400 0 Blue 0
4 AM Thu 53 53 N 3 2605 3400 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