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

Station:

KOAK

Date/Time:

23 SEP 2017

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 50 48 N 8 2743 3400 0 Blue 0
6 AM Sat 50 48 N 8 2743 3400 0 Blue 0
7 AM Sat 50 48 N 8 2743 3400 0 Blue 0
8 AM Sat 52 50 N 9 2743 3400 0 Blue 0
9 AM Sat 56 55 N 9 3883 3400 0 Blue 0
10 AM Sat 61 61 N 9 7309 5587 2187 Blue 6
11 AM Sat 65 67 N 12 9629 9058 5658 White 12
12 Noon Sat 68 71 N 12 10480 10480 7080 White 16
1 PM Sat 70 73 N 12 10891 10891 7491 White 18
2 PM Sat 71 74 N 13 11095 11095 7695 White 19
3 PM Sat 72 74 N 13 11095 11095 7695 White 19
4 PM Sat 72 73 N 13 10891 10891 7491 White 18
5 PM Sat 70 69 N 7 10067 10067 6667 White 14
6 PM Sat 67 65 N 7 9210 7915 4515 White 10
7 PM Sat 63 61 N 7 7309 5587 2187 Blue 6
8 PM Sat 60 58 N 7 5804 3874 474 Blue 3
9 PM Sat 58 56 N 7 4125 3400 0 Blue 1
10 PM Sat 57 55 N 7 3883 3400 0 Blue 0
11 PM Sat 57 55 N 7 3883 3400 0 Blue 0
12 Midnight Sun 57 55 N 7 3883 3400 0 Blue 0
1 AM Sun 57 55 N 7 3883 3400 0 Blue 0
2 AM Sun 56 54 N 7 3176 3400 0 Blue 0
3 AM Sun 56 54 N 7 3176 3400 0 Blue 0
4 AM Sun 55 53 N 7 2743 3400 0 Blue 0
5 AM Sun 54 52 N 8 2743 3400 0 Blue 0
6 AM Sun 54 52 N 8 2743 3400 0 Blue 0
7 AM Sun 54 52 N 8 2743 3400 0 Blue 0
8 AM Sun 56 54 N 8 3176 3400 0 Blue 0
9 AM Sun 60 59 N 8 6229 4114 714 Blue 4
10 AM Sun 65 65 N 8 9210 7915 4515 White 10
11 AM Sun 70 71 N 9 10480 10480 7080 White 16
12 Noon Sun 73 75 N 9 11298 11298 7898 White 20
1 PM Sun 75 78 N 9 11905 11905 8505 White 23
2 PM Sun 76 78 N 9 11905 11905 8505 White 23
3 PM Sun 77 79 N 9 12106 12106 8706 White 24
4 PM Sun 77 77 N 9 11704 11704 8304 White 22
5 PM Sun 75 74 N 9 11095 11095 7695 White 19
6 PM Sun 72 70 N 9 10274 10274 6874 White 15
7 PM Sun 68 66 N 9 9419 8592 5192 White 11
8 PM Sun 64 62 N 9 8037 6182 2782 Blue 7
9 PM Sun 63 61 N 9 7309 5587 2187 Blue 6
10 PM Sun 62 60 N 9 6827 4370 970 Blue 5
11 PM Sun 62 60 N 8 6827 4370 970 Blue 5
12 Midnight Mon 61 59 N 8 6229 4114 714 Blue 4
1 AM Mon 60 58 N 8 5804 3874 474 Blue 3
2 AM Mon 60 58 N 8 5804 3874 474 Blue 3
3 AM Mon 60 58 N 8 5804 3874 474 Blue 3
4 AM Mon 59 57 N 8 4384 3400 0 Blue 2
5 AM Mon 59 57 N 8 4384 3400 0 Blue 2
6 AM Mon 58 56 N 8 4125 3400 0 Blue 1
7 AM Mon 58 56 N 8 4125 3400 0 Blue 1
8 AM Mon 60 58 N 8 5804 3874 474 Blue 3
9 AM Mon 64 63 N 8 8694 6771 3371 Blue 8
10 AM Mon 70 70 N 8 10274 10274 6874 White 15
11 AM Mon 76 78 N 9 11905 11905 8505 White 23
12 Noon Mon 79 82 N 9 12709 12709 9309 White 27
1 PM Mon 81 84 N 9 13110 13110 9710 White 29
2 PM Mon 81 84 N 9 13110 13110 9710 White 29
3 PM Mon 82 84 N 9 13110 13110 9710 White 29
4 PM Mon 82 83 N 9 12909 12909 9509 White 28
5 PM Mon 81 80 N 8 12308 12308 8908 White 25
6 PM Mon 78 76 N 8 11501 11501 8101 White 21
7 PM Mon 74 72 N 8 10686 10686 7286 White 17
8 PM Mon 71 69 N 8 10067 10067 6667 White 14
9 PM Mon 69 67 N 8 9629 9058 5658 White 12
10 PM Mon 68 66 N 8 9419 8592 5192 White 11
11 PM Mon 67 65 N 9 9210 7915 4515 White 10
12 Midnight Tue 66 64 N 9 9000 7197 3797 White 9
1 AM Tue 66 64 N 9 9000 7197 3797 White 9
2 AM Tue 65 63 N 9 8694 6771 3371 Blue 8
3 AM Tue 65 63 N 9 8694 6771 3371 Blue 8
4 AM Tue 65 63 N 9 8694 6771 3371 Blue 8
5 AM Tue 64 62 N 9 8037 6182 2782 Blue 7
6 AM Tue 63 61 N 9 7309 5587 2187 Blue 6
7 AM Tue 63 61 N 9 7309 5587 2187 Blue 6
8 AM Tue 64 62 N 9 8037 6182 2782 Blue 7
9 AM Tue 68 67 N 9 9629 9058 5658 White 12
10 AM Tue 73 73 N 9 10891 10891 7491 White 18
11 AM Tue 78 80 NE 9 12308 12308 8908 White 25
12 Noon Tue 81 84 NE 9 13110 13110 9710 White 29
1 PM Tue 83 86 NE 9 13508 13508 10108 White 31
2 PM Tue 84 87 NE 9 13706 13706 10306 White 32
3 PM Tue 85 87 NE 9 13706 13706 10306 White 32
4 PM Tue 85 86 NE 9 13508 13508 10108 White 31
5 PM Tue 83 82 N 7 12709 12709 9309 White 27
6 PM Tue 80 78 N 7 11905 11905 8505 White 23
7 PM Tue 75 73 N 7 10891 10891 7491 White 18
8 PM Tue 71 69 N 7 10067 10067 6667 White 14
9 PM Tue 68 66 N 7 9419 8592 5192 White 11
10 PM Tue 67 65 N 7 9210 7915 4515 White 10
11 PM Tue 66 64 NE 5 9000 7197 3797 White 9
12 Midnight Wed 65 63 NE 5 8694 6771 3371 Blue 8
1 AM Wed 65 63 NE 5 8694 6771 3371 Blue 8
2 AM Wed 64 62 NE 5 8037 6182 2782 Blue 7
3 AM Wed 64 62 NE 5 8037 6182 2782 Blue 7
4 AM Wed 64 62 NE 5 8037 6182 2782 Blue 7
5 AM Wed 63 61 NE 8 7309 5587 2187 Blue 6
6 AM Wed 62 60 NE 8 6827 4370 970 Blue 5
7 AM Wed 62 60 NE 8 6827 4370 970 Blue 5
8 AM Wed 63 61 NE 8 7309 5587 2187 Blue 6
9 AM Wed 67 66 NE 8 9419 8592 5192 White 11
10 AM Wed 73 73 NE 8 10891 10891 7491 White 18
11 AM Wed 78 79 NE 6 12106 12106 8706 White 24
12 Noon Wed 82 84 NE 6 13110 13110 9710 White 29
1 PM Wed 84 86 NE 6 13508 13508 10108 White 31
2 PM Wed 85 87 NE 6 13706 13706 10306 White 32
3 PM Wed 86 87 NE 6 13706 13706 10306 White 32
4 PM Wed 85 85 NE 6 13309 13309 9909 White 30
5 PM Wed 83 82 E 5 12709 12709 9309 White 27
6 PM Wed 80 78 E 5 11905 11905 8505 White 23
7 PM Wed 76 74 E 5 11095 11095 7695 White 19
8 PM Wed 72 70 E 5 10274 10274 6874 White 15
9 PM Wed 69 67 E 5 9629 9058 5658 White 12
10 PM Wed 67 65 E 5 9210 7915 4515 White 10
11 PM Wed 67 65 W 3 9210 7915 4515 White 10
12 Midnight Thu 66 64 W 3 9000 7197 3797 White 9
1 AM Thu 66 64 W 3 9000 7197 3797 White 9
2 AM Thu 66 64 W 3 9000 7197 3797 White 9
3 AM Thu 65 63 W 3 8694 6771 3371 Blue 8
4 AM Thu 64 62 W 3 8037 6182 2782 Blue 7
5 AM Thu 64 62 NE 2 8037 6182 2782 Blue 7
6 AM Thu 63 61 NE 2 7309 5587 2187 Blue 6
7 AM Thu 63 61 NE 2 7309 5587 2187 Blue 6
8 AM Thu 65 63 NE 2 8694 6771 3371 Blue 8
9 AM Thu 69 67 NE 2 9629 9058 5658 White 12
10 AM Thu 73 73 NE 2 10891 10891 7491 White 18
11 AM Thu 78 79 E 5 12106 12106 8706 White 24
12 Noon Thu 82 84 E 5 13110 13110 9710 White 29
1 PM Thu 84 86 E 5 13508 13508 10108 White 31
2 PM Thu 86 88 E 5 13905 13905 10505 White 33
3 PM Thu 86 87 E 5 13706 13706 10306 White 32
4 PM Thu 85 85 E 5 13309 13309 9909 White 30
5 PM Thu 84 83 S 6 12909 12909 9509 White 28
6 PM Thu 80 78 S 6 11905 11905 8505 White 23
7 PM Thu 76 74 S 6 11095 11095 7695 White 19
8 PM Thu 73 71 S 6 10480 10480 7080 White 16
9 PM Thu 71 69 S 6 10067 10067 6667 White 14
10 PM Thu 69 67 S 6 9629 9058 5658 White 12
11 PM Thu 68 66 NW 3 9419 8592 5192 White 11
12 Midnight Fri 67 65 NW 3 9210 7915 4515 White 10
1 AM Fri 67 65 NW 3 9210 7915 4515 White 10
2 AM Fri 66 64 NW 3 9000 7197 3797 White 9
3 AM Fri 66 64 NW 3 9000 7197 3797 White 9
4 AM Fri 66 64 NW 3 9000 7197 3797 White 9

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