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

Station:

KOAK

Date/Time:

25 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 Sun 70 68 W 6 2635 3400 0 Blue 0
6 AM Sun 75 73 W 6 2635 3400 0 Blue 0
7 AM Sun 70 68 W 6 2635 3400 0 Blue 0
8 AM Sun 78 76 W 2 2635 3400 0 Blue 0
9 AM Sun 85 84 W 2 5499 4141 741 Blue 7
10 AM Sun 86 87 W 2 6786 5460 2060 Blue 10
11 AM Sun 91 94 E 3 8828 7498 4098 Blue 17
12 Noon Sun 93 97 E 3 9554 8790 5390 Blue 20
1 PM Sun 97 102 E 3 10981 9996 6596 Blue 25
2 PM Sun 99 104 S 6 11438 10804 7404 Blue 27
3 PM Sun 99 103 S 6 11122 10663 7263 Blue 26
4 PM Sun 99 101 S 6 10840 9748 6348 Blue 24
5 PM Sun 97 97 SW 8 9554 8790 5390 Blue 20
6 PM Sun 92 91 SW 8 7514 7016 3616 Blue 14
7 PM Sun 82 80 SW 8 3865 3400 0 Blue 4
8 PM Sun 80 78 W 10 2998 3400 0 Blue 2
9 PM Sun 80 78 W 10 2998 3400 0 Blue 2
10 PM Sun 78 76 W 10 2635 3400 0 Blue 0
11 PM Sun 76 74 W 3 2635 3400 0 Blue 0
12 Midnight Mon 76 74 W 3 2635 3400 0 Blue 0
1 AM Mon 75 73 W 3 2635 3400 0 Blue 0
2 AM Mon 75 73 NW 3 2635 3400 0 Blue 0
3 AM Mon 72 70 NW 3 2635 3400 0 Blue 0
4 AM Mon 71 69 NW 3 2635 3400 0 Blue 0
5 AM Mon 71 69 N 3 2635 3400 0 Blue 0
6 AM Mon 70 68 N 3 2635 3400 0 Blue 0
7 AM Mon 70 68 N 3 2635 3400 0 Blue 0
8 AM Mon 79 77 N 3 2859 3400 0 Blue 1
9 AM Mon 85 84 N 3 5499 4141 741 Blue 7
10 AM Mon 87 88 N 3 7051 5913 2513 Blue 11
11 AM Mon 90 93 E 5 8626 7389 3989 Blue 16
12 Noon Mon 95 99 E 5 10353 9249 5849 Blue 22
1 PM Mon 97 102 E 5 10981 9996 6596 Blue 25
2 PM Mon 99 104 SE 6 11438 10804 7404 Blue 27
3 PM Mon 101 105 SE 6 12213 10944 7544 Blue 28
4 PM Mon 101 103 SE 6 11122 10663 7263 Blue 26
5 PM Mon 99 99 S 10 10353 9249 5849 Blue 22
6 PM Mon 94 93 S 10 8626 7389 3989 Blue 16
7 PM Mon 87 85 S 10 5958 4372 972 Blue 8
8 PM Mon 81 79 S 10 3575 3400 0 Blue 3
9 PM Mon 77 75 S 10 2635 3400 0 Blue 0
10 PM Mon 76 74 S 10 2635 3400 0 Blue 0
11 PM Mon 76 74 N 3 2635 3400 0 Blue 0
12 Midnight Tue 75 73 N 3 2635 3400 0 Blue 0
1 AM Tue 75 73 N 3 2635 3400 0 Blue 0
2 AM Tue 73 71 N 3 2635 3400 0 Blue 0
3 AM Tue 72 70 N 3 2635 3400 0 Blue 0
4 AM Tue 71 69 N 3 2635 3400 0 Blue 0
5 AM Tue 71 69 NE 3 2635 3400 0 Blue 0
6 AM Tue 72 70 NE 3 2635 3400 0 Blue 0
7 AM Tue 75 73 NE 3 2635 3400 0 Blue 0
8 AM Tue 78 76 NE 3 2635 3400 0 Blue 0
9 AM Tue 82 81 NE 3 4154 3400 0 Blue 5
10 AM Tue 87 88 NE 3 7051 5913 2513 Blue 11
11 AM Tue 91 94 SE 5 8828 7498 4098 Blue 17
12 Noon Tue 95 99 SE 5 10353 9249 5849 Blue 22
1 PM Tue 97 102 SE 5 10981 9996 6596 Blue 25
2 PM Tue 100 105 SE 5 12213 10944 7544 Blue 28
3 PM Tue 101 105 SE 5 12213 10944 7544 Blue 28
4 PM Tue 101 103 SE 5 11122 10663 7263 Blue 26
5 PM Tue 98 98 SW 7 9804 8998 5598 Blue 21
6 PM Tue 93 92 SW 7 7959 7278 3878 Blue 15
7 PM Tue 87 85 SW 7 5958 4372 972 Blue 8
8 PM Tue 81 79 SW 7 3575 3400 0 Blue 3
9 PM Tue 78 76 SW 7 2635 3400 0 Blue 0
10 PM Tue 78 76 SW 7 2635 3400 0 Blue 0
11 PM Tue 78 76 SW 6 2635 3400 0 Blue 0
12 Midnight Wed 77 75 SW 6 2635 3400 0 Blue 0
1 AM Wed 77 75 SW 6 2635 3400 0 Blue 0
2 AM Wed 75 73 SW 6 2635 3400 0 Blue 0
3 AM Wed 74 72 SW 6 2635 3400 0 Blue 0
4 AM Wed 73 71 SW 6 2635 3400 0 Blue 0
5 AM Wed 72 70 NW 3 2635 3400 0 Blue 0
6 AM Wed 73 71 NW 3 2635 3400 0 Blue 0
7 AM Wed 75 73 NW 3 2635 3400 0 Blue 0
8 AM Wed 78 76 NW 3 2635 3400 0 Blue 0
9 AM Wed 82 81 NW 3 4154 3400 0 Blue 5
10 AM Wed 86 86 NW 3 6409 4953 1553 Blue 9
11 AM Wed 90 92 S 7 7959 7278 3878 Blue 15
12 Noon Wed 93 96 S 7 9302 8589 5189 Blue 19
1 PM Wed 95 98 S 7 9804 8998 5598 Blue 21
2 PM Wed 97 100 S 7 10699 9499 6099 Blue 23
3 PM Wed 98 101 S 7 10840 9748 6348 Blue 24
4 PM Wed 97 98 S 7 9804 8998 5598 Blue 21
5 PM Wed 95 95 SW 10 9048 7621 4221 Blue 18
6 PM Wed 89 88 SW 10 7051 5913 2513 Blue 11
7 PM Wed 83 81 SW 10 4154 3400 0 Blue 5
8 PM Wed 78 76 SW 10 2635 3400 0 Blue 0
9 PM Wed 76 74 SW 10 2635 3400 0 Blue 0
10 PM Wed 76 74 SW 10 2635 3400 0 Blue 0
11 PM Wed 76 74 W 6 2635 3400 0 Blue 0
12 Midnight Thu 76 74 W 6 2635 3400 0 Blue 0
1 AM Thu 75 73 W 6 2635 3400 0 Blue 0
2 AM Thu 74 72 W 6 2635 3400 0 Blue 0
3 AM Thu 72 70 W 6 2635 3400 0 Blue 0
4 AM Thu 71 69 W 6 2635 3400 0 Blue 0
5 AM Thu 70 68 W 3 2635 3400 0 Blue 0
6 AM Thu 71 69 W 3 2635 3400 0 Blue 0
7 AM Thu 73 71 W 3 2635 3400 0 Blue 0
8 AM Thu 76 74 W 3 2635 3400 0 Blue 0
9 AM Thu 80 79 W 3 3575 3400 0 Blue 3
10 AM Thu 83 84 W 3 5499 4141 741 Blue 7
11 AM Thu 87 90 S 7 7405 6752 3352 Blue 13
12 Noon Thu 90 94 S 7 8828 7498 4098 Blue 17
1 PM Thu 92 97 S 7 9554 8790 5390 Blue 20
2 PM Thu 94 99 S 7 10353 9249 5849 Blue 22
3 PM Thu 95 99 S 7 10353 9249 5849 Blue 22
4 PM Thu 95 97 S 7 9554 8790 5390 Blue 20
5 PM Thu 92 92 SW 9 7959 7278 3878 Blue 15
6 PM Thu 87 86 SW 9 6409 4953 1553 Blue 9
7 PM Thu 81 79 SW 9 3575 3400 0 Blue 3
8 PM Thu 77 75 SW 9 2635 3400 0 Blue 0
9 PM Thu 75 73 SW 9 2635 3400 0 Blue 0
10 PM Thu 74 72 SW 9 2635 3400 0 Blue 0
11 PM Thu 74 72 W 5 2635 3400 0 Blue 0
12 Midnight Fri 74 72 W 5 2635 3400 0 Blue 0
1 AM Fri 74 72 W 5 2635 3400 0 Blue 0
2 AM Fri 72 70 W 5 2635 3400 0 Blue 0
3 AM Fri 71 69 W 5 2635 3400 0 Blue 0
4 AM Fri 69 67 W 5 2635 3400 0 Blue 0
5 AM Fri 69 67 N 3 2635 3400 0 Blue 0
6 AM Fri 70 68 N 3 2635 3400 0 Blue 0
7 AM Fri 73 71 N 3 2635 3400 0 Blue 0
8 AM Fri 76 74 N 3 2635 3400 0 Blue 0
9 AM Fri 79 78 N 3 2998 3400 0 Blue 2
10 AM Fri 82 83 N 3 5010 3855 455 Blue 6
11 AM Fri 85 88 SE 6 7051 5913 2513 Blue 11
12 Noon Fri 89 93 SE 6 8626 7389 3989 Blue 16
1 PM Fri 92 97 SE 6 9554 8790 5390 Blue 20
2 PM Fri 95 100 SE 6 10699 9499 6099 Blue 23
3 PM Fri 96 100 SE 6 10699 9499 6099 Blue 23
4 PM Fri 95 97 SE 6 9554 8790 5390 Blue 20
5 PM Fri 93 93 W 8 8626 7389 3989 Blue 16
6 PM Fri 87 86 W 8 6409 4953 1553 Blue 9
7 PM Fri 81 79 W 8 3575 3400 0 Blue 3
8 PM Fri 76 74 W 8 2635 3400 0 Blue 0
9 PM Fri 74 72 W 8 2635 3400 0 Blue 0
10 PM Fri 73 71 W 8 2635 3400 0 Blue 0
11 PM Fri 73 71 W 6 2635 3400 0 Blue 0
12 Midnight Sat 73 71 W 6 2635 3400 0 Blue 0
1 AM Sat 73 71 W 6 2635 3400 0 Blue 0
2 AM Sat 72 70 W 6 2635 3400 0 Blue 0
3 AM Sat 70 68 W 6 2635 3400 0 Blue 0
4 AM Sat 68 66 W 6 2635 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