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

Station:

KOAK

Date/Time:

24 AUG 2019

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 72 70 W 6 2710 3400 0 Blue 0
6 AM Sat 75 73 W 6 2710 3400 0 Blue 0
7 AM Sat 70 68 W 6 2710 3400 0 Blue 0
8 AM Sat 78 76 SE 5 2900 3400 0 Blue 0
9 AM Sat 84 83 SE 5 5384 3510 110 Blue 4
10 AM Sat 85 86 SE 5 6162 5365 1965 Blue 7
11 AM Sat 88 91 S 7 7689 7252 3852 Blue 12
12 Noon Sat 92 96 S 7 8705 8159 4759 Blue 17
1 PM Sat 95 100 S 7 9365 8793 5393 Blue 21
2 PM Sat 97 102 S 7 10205 9025 5625 Blue 23
3 PM Sat 98 102 S 7 10205 9025 5625 Blue 23
4 PM Sat 98 100 S 7 9365 8793 5393 Blue 21
5 PM Sat 95 95 SW 9 8596 7806 4406 Blue 16
6 PM Sat 92 91 SW 9 7689 7252 3852 Blue 12
7 PM Sat 82 80 SW 9 3513 3400 0 Blue 1
8 PM Sat 80 78 W 7 3120 3400 0 Blue 0
9 PM Sat 80 78 W 7 3120 3400 0 Blue 0
10 PM Sat 79 77 W 7 3010 3400 0 Blue 0
11 PM Sat 77 75 W 8 2791 3400 0 Blue 0
12 Midnight Sun 76 74 W 8 2710 3400 0 Blue 0
1 AM Sun 75 73 W 8 2710 3400 0 Blue 0
2 AM Sun 75 73 W 5 2710 3400 0 Blue 0
3 AM Sun 74 72 W 5 2710 3400 0 Blue 0
4 AM Sun 73 71 W 5 2710 3400 0 Blue 0
5 AM Sun 73 71 W 3 2710 3400 0 Blue 0
6 AM Sun 71 69 W 3 2710 3400 0 Blue 0
7 AM Sun 72 70 W 3 2710 3400 0 Blue 0
8 AM Sun 79 77 W 2 3010 3400 0 Blue 0
9 AM Sun 84 83 W 2 5384 3510 110 Blue 4
10 AM Sun 86 87 W 2 7133 5597 2197 Blue 8
11 AM Sun 90 93 S 5 8223 7529 4129 Blue 14
12 Noon Sun 93 97 S 5 8815 8467 5067 Blue 18
1 PM Sun 95 100 S 5 9365 8793 5393 Blue 21
2 PM Sun 97 102 S 12 10205 9025 5625 Blue 23
3 PM Sun 98 102 S 12 10205 9025 5625 Blue 23
4 PM Sun 98 100 S 12 9365 8793 5393 Blue 21
5 PM Sun 96 96 S 10 8705 8159 4759 Blue 17
6 PM Sun 90 89 S 10 7411 6125 2725 Blue 10
7 PM Sun 84 82 S 10 4766 3400 0 Blue 3
8 PM Sun 79 77 SW 7 3010 3400 0 Blue 0
9 PM Sun 77 75 SW 7 2791 3400 0 Blue 0
10 PM Sun 76 74 SW 7 2710 3400 0 Blue 0
11 PM Sun 77 75 NW 6 2791 3400 0 Blue 0
12 Midnight Mon 76 74 NW 6 2710 3400 0 Blue 0
1 AM Mon 75 73 NW 6 2710 3400 0 Blue 0
2 AM Mon 73 71 N 2 2710 3400 0 Blue 0
3 AM Mon 72 70 N 2 2710 3400 0 Blue 0
4 AM Mon 71 69 N 2 2710 3400 0 Blue 0
5 AM Mon 71 69 NE 2 2710 3400 0 Blue 0
6 AM Mon 72 70 NE 2 2710 3400 0 Blue 0
7 AM Mon 74 72 NE 2 2710 3400 0 Blue 0
8 AM Mon 78 76 NE 2 2900 3400 0 Blue 0
9 AM Mon 82 81 NE 2 4213 3400 0 Blue 2
10 AM Mon 87 88 NE 2 7272 5828 2428 Blue 9
11 AM Mon 91 94 SE 7 8487 7668 4268 Blue 15
12 Noon Mon 94 98 SE 7 8924 8576 5176 Blue 19
1 PM Mon 97 102 SE 7 10205 9025 5625 Blue 23
2 PM Mon 99 104 SE 7 11146 9585 6185 Blue 25
3 PM Mon 101 105 SE 7 11592 10064 6664 Blue 26
4 PM Mon 101 103 SE 7 10702 9306 5906 Blue 24
5 PM Mon 99 99 S 6 9082 8685 5285 Blue 20
6 PM Mon 93 92 S 6 7846 7391 3991 Blue 13
7 PM Mon 86 84 S 6 5618 4156 756 Blue 5
8 PM Mon 81 79 S 6 3373 3400 0 Blue 0
9 PM Mon 79 77 S 6 3010 3400 0 Blue 0
10 PM Mon 78 76 S 6 2900 3400 0 Blue 0
11 PM Mon 79 77 N 3 3010 3400 0 Blue 0
12 Midnight Tue 78 76 N 3 2900 3400 0 Blue 0
1 AM Tue 77 75 N 3 2791 3400 0 Blue 0
2 AM Tue 75 73 N 3 2710 3400 0 Blue 0
3 AM Tue 74 72 N 3 2710 3400 0 Blue 0
4 AM Tue 72 70 N 3 2710 3400 0 Blue 0
5 AM Tue 72 70 NE 2 2710 3400 0 Blue 0
6 AM Tue 73 71 NE 2 2710 3400 0 Blue 0
7 AM Tue 76 74 NE 2 2710 3400 0 Blue 0
8 AM Tue 80 78 NE 2 3120 3400 0 Blue 0
9 AM Tue 84 83 NE 2 5384 3510 110 Blue 4
10 AM Tue 88 89 NE 2 7411 6125 2725 Blue 10
11 AM Tue 92 94 SE 5 8487 7668 4268 Blue 15
12 Noon Tue 95 99 SE 5 9082 8685 5285 Blue 20
1 PM Tue 98 102 SE 5 10205 9025 5625 Blue 23
2 PM Tue 100 104 SE 5 11146 9585 6185 Blue 25
3 PM Tue 102 105 SE 5 11592 10064 6664 Blue 26
4 PM Tue 102 104 SE 5 11146 9585 6185 Blue 25
5 PM Tue 99 99 SW 7 9082 8685 5285 Blue 20
6 PM Tue 93 92 SW 7 7846 7391 3991 Blue 13
7 PM Tue 86 84 SW 7 5618 4156 756 Blue 5
8 PM Tue 80 78 SW 7 3120 3400 0 Blue 0
9 PM Tue 78 76 SW 7 2900 3400 0 Blue 0
10 PM Tue 77 75 SW 7 2791 3400 0 Blue 0
11 PM Tue 78 76 SW 5 2900 3400 0 Blue 0
12 Midnight Wed 77 75 SW 5 2791 3400 0 Blue 0
1 AM Wed 76 74 SW 5 2710 3400 0 Blue 0
2 AM Wed 74 72 SW 5 2710 3400 0 Blue 0
3 AM Wed 72 70 SW 5 2710 3400 0 Blue 0
4 AM Wed 71 69 SW 5 2710 3400 0 Blue 0
5 AM Wed 71 69 NW 2 2710 3400 0 Blue 0
6 AM Wed 72 70 NW 2 2710 3400 0 Blue 0
7 AM Wed 75 73 NW 2 2710 3400 0 Blue 0
8 AM Wed 77 75 NW 2 2791 3400 0 Blue 0
9 AM Wed 80 79 NW 2 3373 3400 0 Blue 0
10 AM Wed 83 84 NW 2 5618 4156 756 Blue 5
11 AM Wed 86 89 S 6 7411 6125 2725 Blue 10
12 Noon Wed 88 92 S 6 7846 7391 3991 Blue 13
1 PM Wed 90 95 S 6 8596 7806 4406 Blue 16
2 PM Wed 92 96 S 6 8705 8159 4759 Blue 17
3 PM Wed 93 96 S 6 8705 8159 4759 Blue 17
4 PM Wed 93 95 S 6 8596 7806 4406 Blue 16
5 PM Wed 90 90 SW 9 7550 7114 3714 Blue 11
6 PM Wed 86 85 SW 9 5851 4741 1341 Blue 6
7 PM Wed 81 79 SW 9 3373 3400 0 Blue 0
8 PM Wed 77 75 SW 9 2791 3400 0 Blue 0
9 PM Wed 76 74 SW 9 2710 3400 0 Blue 0
10 PM Wed 75 73 SW 9 2710 3400 0 Blue 0
11 PM Wed 76 74 W 5 2710 3400 0 Blue 0
12 Midnight Thu 75 73 W 5 2710 3400 0 Blue 0
1 AM Thu 74 72 W 5 2710 3400 0 Blue 0
2 AM Thu 73 71 W 5 2710 3400 0 Blue 0
3 AM Thu 71 69 W 5 2710 3400 0 Blue 0
4 AM Thu 70 68 W 5 2710 3400 0 Blue 0
5 AM Thu 70 68 W 2 2710 3400 0 Blue 0
6 AM Thu 71 69 W 2 2710 3400 0 Blue 0
7 AM Thu 72 70 W 2 2710 3400 0 Blue 0
8 AM Thu 74 72 W 2 2710 3400 0 Blue 0
9 AM Thu 77 76 W 2 2900 3400 0 Blue 0
10 AM Thu 79 80 W 2 3513 3400 0 Blue 1
11 AM Thu 82 85 S 6 5851 4741 1341 Blue 6
12 Noon Thu 84 88 S 6 7272 5828 2428 Blue 9
1 PM Thu 86 91 S 6 7689 7252 3852 Blue 12
2 PM Thu 88 92 S 6 7846 7391 3991 Blue 13
3 PM Thu 89 92 S 6 7846 7391 3991 Blue 13
4 PM Thu 89 91 S 6 7689 7252 3852 Blue 12
5 PM Thu 87 87 SW 8 7133 5597 2197 Blue 8
6 PM Thu 83 82 SW 8 4766 3400 0 Blue 3
7 PM Thu 78 76 SW 8 2900 3400 0 Blue 0
8 PM Thu 74 72 SW 8 2710 3400 0 Blue 0
9 PM Thu 73 71 SW 8 2710 3400 0 Blue 0
10 PM Thu 72 70 SW 8 2710 3400 0 Blue 0
11 PM Thu 73 71 W 5 2710 3400 0 Blue 0
12 Midnight Fri 73 71 W 5 2710 3400 0 Blue 0
1 AM Fri 72 70 W 5 2710 3400 0 Blue 0
2 AM Fri 72 70 W 5 2710 3400 0 Blue 0
3 AM Fri 71 69 W 5 2710 3400 0 Blue 0
4 AM Fri 69 67 W 5 2710 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