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

Station:

KOAK

Date/Time:

16 OCT 2018

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 Tue 53 51 N 6 2717 3400 0 Blue 0
6 AM Tue 52 50 N 6 2717 3400 0 Blue 0
7 AM Tue 52 50 N 6 2717 3400 0 Blue 0
8 AM Tue 54 52 N 7 2717 3400 0 Blue 0
9 AM Tue 58 56 N 7 2717 3400 0 Blue 0
10 AM Tue 64 63 N 7 2717 3400 0 Blue 0
11 AM Tue 70 71 NE 8 4897 4505 1105 Blue 4
12 Noon Tue 74 75 NE 8 6696 5123 1723 Blue 8
1 PM Tue 77 79 NE 8 8966 7521 4121 Blue 12
2 PM Tue 78 80 NE 8 9211 8384 4984 Blue 13
3 PM Tue 79 80 NE 8 9211 8384 4984 Blue 13
4 PM Tue 79 78 NE 8 8720 6569 3169 Blue 11
5 PM Tue 76 74 NE 5 5668 4881 1481 Blue 7
6 PM Tue 72 70 NE 5 4724 4271 871 Blue 3
7 PM Tue 67 65 NE 5 3309 3400 0 Blue 0
8 PM Tue 63 61 N 6 2717 3400 0 Blue 0
9 PM Tue 61 59 N 6 2717 3400 0 Blue 0
10 PM Tue 60 58 N 6 2717 3400 0 Blue 0
11 PM Tue 60 58 N 6 2717 3400 0 Blue 0
12 Midnight Wed 60 58 N 6 2717 3400 0 Blue 0
1 AM Wed 59 57 N 6 2717 3400 0 Blue 0
2 AM Wed 58 56 N 6 2717 3400 0 Blue 0
3 AM Wed 58 56 N 6 2717 3400 0 Blue 0
4 AM Wed 57 55 N 6 2717 3400 0 Blue 0
5 AM Wed 56 54 N 6 2717 3400 0 Blue 0
6 AM Wed 55 53 N 6 2717 3400 0 Blue 0
7 AM Wed 54 52 N 6 2717 3400 0 Blue 0
8 AM Wed 55 53 N 5 2717 3400 0 Blue 0
9 AM Wed 59 57 N 5 2717 3400 0 Blue 0
10 AM Wed 64 63 N 5 2717 3400 0 Blue 0
11 AM Wed 69 69 NE 5 4629 3798 398 Blue 2
12 Noon Wed 72 73 NE 5 5406 4718 1318 Blue 6
1 PM Wed 75 77 NE 5 8473 5644 2244 Blue 10
2 PM Wed 76 77 NE 6 8473 5644 2244 Blue 10
3 PM Wed 76 77 NE 6 8473 5644 2244 Blue 10
4 PM Wed 75 74 NE 6 5668 4881 1481 Blue 7
5 PM Wed 73 71 S 3 4897 4505 1105 Blue 4
6 PM Wed 69 67 S 3 4283 3400 0 Blue 0
7 PM Wed 65 63 S 3 2717 3400 0 Blue 0
8 PM Wed 61 59 S 3 2717 3400 0 Blue 0
9 PM Wed 60 58 S 3 2717 3400 0 Blue 0
10 PM Wed 59 57 S 3 2717 3400 0 Blue 0
11 PM Wed 59 57 NW 3 2717 3400 0 Blue 0
12 Midnight Thu 59 57 NW 3 2717 3400 0 Blue 0
1 AM Thu 58 56 NW 3 2717 3400 0 Blue 0
2 AM Thu 57 55 NW 3 2717 3400 0 Blue 0
3 AM Thu 57 55 NW 3 2717 3400 0 Blue 0
4 AM Thu 56 54 NW 3 2717 3400 0 Blue 0
5 AM Thu 55 53 N 3 2717 3400 0 Blue 0
6 AM Thu 54 52 N 3 2717 3400 0 Blue 0
7 AM Thu 54 52 N 3 2717 3400 0 Blue 0
8 AM Thu 55 53 N 3 2717 3400 0 Blue 0
9 AM Thu 59 57 N 3 2717 3400 0 Blue 0
10 AM Thu 64 63 N 3 2717 3400 0 Blue 0
11 AM Thu 69 70 E 3 4724 4271 871 Blue 3
12 Noon Thu 72 73 E 3 5406 4718 1318 Blue 6
1 PM Thu 74 76 E 3 7664 5384 1984 Blue 9
2 PM Thu 75 77 E 3 8473 5644 2244 Blue 10
3 PM Thu 75 76 E 3 7664 5384 1984 Blue 9
4 PM Thu 75 74 E 3 5668 4881 1481 Blue 7
5 PM Thu 73 71 SW 2 4897 4505 1105 Blue 4
6 PM Thu 69 67 SW 2 4283 3400 0 Blue 0
7 PM Thu 64 62 SW 2 2717 3400 0 Blue 0
8 PM Thu 61 59 SW 2 2717 3400 0 Blue 0
9 PM Thu 59 57 SW 2 2717 3400 0 Blue 0
10 PM Thu 59 57 SW 2 2717 3400 0 Blue 0
11 PM Thu 59 57 NW 3 2717 3400 0 Blue 0
12 Midnight Fri 58 56 NW 3 2717 3400 0 Blue 0
1 AM Fri 57 55 NW 3 2717 3400 0 Blue 0
2 AM Fri 57 55 NW 3 2717 3400 0 Blue 0
3 AM Fri 56 54 NW 3 2717 3400 0 Blue 0
4 AM Fri 56 54 NW 3 2717 3400 0 Blue 0
5 AM Fri 57 55 N 3 2717 3400 0 Blue 0
6 AM Fri 59 57 N 3 2717 3400 0 Blue 0
7 AM Fri 61 59 N 3 2717 3400 0 Blue 0
8 AM Fri 64 62 N 3 2717 3400 0 Blue 0
9 AM Fri 68 66 N 3 3815 3400 0 Blue 0
10 AM Fri 71 70 N 3 4724 4271 871 Blue 3
11 AM Fri 74 75 N 3 6696 5123 1723 Blue 8
12 Noon Fri 77 78 N 3 8720 6569 3169 Blue 11
1 PM Fri 78 80 N 3 9211 8384 4984 Blue 13
2 PM Fri 80 82 N 3 10149 8916 5516 Blue 15
3 PM Fri 80 81 N 3 9591 8672 5272 Blue 14
4 PM Fri 80 79 N 3 8966 7521 4121 Blue 12
5 PM Fri 79 77 N 3 8473 5644 2244 Blue 10
6 PM Fri 77 75 N 3 6696 5123 1723 Blue 8
7 PM Fri 74 72 N 3 5143 4623 1223 Blue 5
8 PM Fri 71 69 N 3 4629 3798 398 Blue 2
9 PM Fri 68 66 N 3 3815 3400 0 Blue 0
10 PM Fri 65 63 N 3 2717 3400 0 Blue 0
11 PM Fri 63 61 N 5 2717 3400 0 Blue 0
12 Midnight Sat 60 58 N 5 2717 3400 0 Blue 0
1 AM Sat 59 57 N 5 2717 3400 0 Blue 0
2 AM Sat 58 56 N 5 2717 3400 0 Blue 0
3 AM Sat 57 55 N 5 2717 3400 0 Blue 0
4 AM Sat 57 55 N 5 2717 3400 0 Blue 0
5 AM Sat 58 56 N 5 2717 3400 0 Blue 0
6 AM Sat 60 58 N 5 2717 3400 0 Blue 0
7 AM Sat 62 60 N 5 2717 3400 0 Blue 0
8 AM Sat 64 62 N 5 2717 3400 0 Blue 0
9 AM Sat 67 65 N 5 3309 3400 0 Blue 0
10 AM Sat 70 69 N 5 4629 3798 398 Blue 2
11 AM Sat 73 74 NE 3 5668 4881 1481 Blue 7
12 Noon Sat 75 76 NE 3 7664 5384 1984 Blue 9
1 PM Sat 76 78 NE 3 8720 6569 3169 Blue 11
2 PM Sat 78 80 NE 3 9211 8384 4984 Blue 13
3 PM Sat 78 79 NE 3 8966 7521 4121 Blue 12
4 PM Sat 78 77 NE 3 8473 5644 2244 Blue 10
5 PM Sat 77 75 S 2 6696 5123 1723 Blue 8
6 PM Sat 75 73 S 2 5406 4718 1318 Blue 6
7 PM Sat 72 70 S 2 4724 4271 871 Blue 3
8 PM Sat 69 67 S 2 4283 3400 0 Blue 0
9 PM Sat 66 64 S 2 2789 3400 0 Blue 0
10 PM Sat 63 61 S 2 2717 3400 0 Blue 0
11 PM Sat 60 58 NE 2 2717 3400 0 Blue 0
12 Midnight Sun 58 56 NE 2 2717 3400 0 Blue 0
1 AM Sun 56 54 NE 2 2717 3400 0 Blue 0
2 AM Sun 55 53 NE 2 2717 3400 0 Blue 0
3 AM Sun 55 53 NE 2 2717 3400 0 Blue 0
4 AM Sun 55 53 NE 2 2717 3400 0 Blue 0
5 AM Sun 56 54 NE 2 2717 3400 0 Blue 0
6 AM Sun 58 56 NE 2 2717 3400 0 Blue 0
7 AM Sun 60 58 NE 2 2717 3400 0 Blue 0
8 AM Sun 62 60 NE 2 2717 3400 0 Blue 0
9 AM Sun 65 63 NE 2 2717 3400 0 Blue 0
10 AM Sun 68 67 NE 2 4283 3400 0 Blue 0
11 AM Sun 70 71 SE 2 4897 4505 1105 Blue 4
12 Noon Sun 72 73 SE 2 5406 4718 1318 Blue 6
1 PM Sun 74 76 SE 2 7664 5384 1984 Blue 9
2 PM Sun 75 77 SE 2 8473 5644 2244 Blue 10
3 PM Sun 75 76 SE 2 7664 5384 1984 Blue 9
4 PM Sun 75 74 SE 2 5668 4881 1481 Blue 7
5 PM Sun 74 72 SW 5 5143 4623 1223 Blue 5
6 PM Sun 72 70 SW 5 4724 4271 871 Blue 3
7 PM Sun 69 67 SW 5 4283 3400 0 Blue 0
8 PM Sun 67 65 SW 5 3309 3400 0 Blue 0
9 PM Sun 64 62 SW 5 2717 3400 0 Blue 0
10 PM Sun 61 59 SW 5 2717 3400 0 Blue 0
11 PM Sun 58 56 W 5 2717 3400 0 Blue 0
12 Midnight Mon 56 54 W 5 2717 3400 0 Blue 0
1 AM Mon 55 53 W 5 2717 3400 0 Blue 0
2 AM Mon 54 52 W 5 2717 3400 0 Blue 0
3 AM Mon 54 52 W 5 2717 3400 0 Blue 0
4 AM Mon 54 52 W 5 2717 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