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

Station:

KOAK

Date/Time:

19 AUG 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 Sun 69 67 N 5 2635 3400 0 Blue 0
6 AM Sun 69 67 N 5 2635 3400 0 Blue 0
7 AM Sun 71 69 N 5 2635 3400 0 Blue 0
8 AM Sun 73 71 N 3 2635 3400 0 Blue 0
9 AM Sun 77 76 N 3 2635 3400 0 Blue 0
10 AM Sun 82 83 N 3 3171 3400 0 Blue 1
11 AM Sun 86 89 E 6 6406 4527 1127 Blue 7
12 Noon Sun 89 94 E 6 8229 6833 3433 Blue 12
1 PM Sun 91 96 E 6 9158 7672 4272 Blue 14
2 PM Sun 93 98 SE 10 10049 8612 5212 Blue 16
3 PM Sun 93 97 SE 10 9608 8147 4747 Blue 15
4 PM Sun 92 94 SE 10 8229 6833 3433 Blue 12
5 PM Sun 90 91 S 8 6862 5812 2412 Blue 9
6 PM Sun 87 86 S 8 4564 3400 0 Blue 4
7 PM Sun 83 81 S 8 2731 3400 0 Blue 0
8 PM Sun 79 77 SW 9 2635 3400 0 Blue 0
9 PM Sun 76 74 SW 9 2635 3400 0 Blue 0
10 PM Sun 74 72 SW 9 2635 3400 0 Blue 0
11 PM Sun 73 71 NW 6 2635 3400 0 Blue 0
12 Midnight Mon 72 70 NW 6 2635 3400 0 Blue 0
1 AM Mon 71 69 NW 6 2635 3400 0 Blue 0
2 AM Mon 71 69 N 3 2635 3400 0 Blue 0
3 AM Mon 70 68 N 3 2635 3400 0 Blue 0
4 AM Mon 69 67 N 3 2635 3400 0 Blue 0
5 AM Mon 68 66 N 2 2635 3400 0 Blue 0
6 AM Mon 68 66 N 2 2635 3400 0 Blue 0
7 AM Mon 69 67 N 2 2635 3400 0 Blue 0
8 AM Mon 71 69 N 5 2635 3400 0 Blue 0
9 AM Mon 76 75 N 5 2635 3400 0 Blue 0
10 AM Mon 81 82 N 5 2875 3400 0 Blue 0
11 AM Mon 85 88 NE 7 5872 3839 439 Blue 6
12 Noon Mon 88 93 NE 7 7748 6607 3207 Blue 11
1 PM Mon 89 94 NE 7 8229 6833 3433 Blue 12
2 PM Mon 90 95 E 12 8698 7186 3786 Blue 13
3 PM Mon 91 95 E 12 8698 7186 3786 Blue 13
4 PM Mon 91 93 E 12 7748 6607 3207 Blue 11
5 PM Mon 89 90 SE 8 6635 5183 1783 Blue 8
6 PM Mon 85 84 SE 8 3473 3400 0 Blue 2
7 PM Mon 80 78 SE 8 2635 3400 0 Blue 0
8 PM Mon 76 74 SE 8 2635 3400 0 Blue 0
9 PM Mon 73 71 SE 8 2635 3400 0 Blue 0
10 PM Mon 71 69 SE 8 2635 3400 0 Blue 0
11 PM Mon 70 68 E 2 2635 3400 0 Blue 0
12 Midnight Tue 69 67 E 2 2635 3400 0 Blue 0
1 AM Tue 68 66 E 2 2635 3400 0 Blue 0
2 AM Tue 67 65 E 2 2635 3400 0 Blue 0
3 AM Tue 66 64 E 2 2635 3400 0 Blue 0
4 AM Tue 65 63 E 2 2635 3400 0 Blue 0
5 AM Tue 64 62 N 5 2635 3400 0 Blue 0
6 AM Tue 64 62 N 5 2635 3400 0 Blue 0
7 AM Tue 65 63 N 5 2635 3400 0 Blue 0
8 AM Tue 67 65 N 5 2635 3400 0 Blue 0
9 AM Tue 71 70 N 5 2635 3400 0 Blue 0
10 AM Tue 75 76 N 5 2635 3400 0 Blue 0
11 AM Tue 79 82 E 8 2875 3400 0 Blue 0
12 Noon Tue 82 86 E 8 4564 3400 0 Blue 4
1 PM Tue 83 88 E 8 5872 3839 439 Blue 6
2 PM Tue 85 90 E 8 6635 5183 1783 Blue 8
3 PM Tue 86 90 E 8 6635 5183 1783 Blue 8
4 PM Tue 86 88 E 8 5872 3839 439 Blue 6
5 PM Tue 85 86 SE 14 4564 3400 0 Blue 4
6 PM Tue 81 80 SE 14 2635 3400 0 Blue 0
7 PM Tue 76 74 SE 14 2635 3400 0 Blue 0
8 PM Tue 72 70 SE 14 2635 3400 0 Blue 0
9 PM Tue 69 67 SE 14 2635 3400 0 Blue 0
10 PM Tue 67 65 SE 14 2635 3400 0 Blue 0
11 PM Tue 66 64 N 5 2635 3400 0 Blue 0
12 Midnight Wed 65 63 N 5 2635 3400 0 Blue 0
1 AM Wed 65 63 N 5 2635 3400 0 Blue 0
2 AM Wed 64 62 N 5 2635 3400 0 Blue 0
3 AM Wed 63 61 N 5 2635 3400 0 Blue 0
4 AM Wed 62 60 N 5 2635 3400 0 Blue 0
5 AM Wed 62 60 N 3 2635 3400 0 Blue 0
6 AM Wed 62 60 N 3 2635 3400 0 Blue 0
7 AM Wed 63 61 N 3 2635 3400 0 Blue 0
8 AM Wed 66 64 N 3 2635 3400 0 Blue 0
9 AM Wed 71 70 N 3 2635 3400 0 Blue 0
10 AM Wed 76 77 N 3 2635 3400 0 Blue 0
11 AM Wed 81 84 S 5 3473 3400 0 Blue 2
12 Noon Wed 85 89 S 5 6406 4527 1127 Blue 7
1 PM Wed 86 91 S 5 6862 5812 2412 Blue 9
2 PM Wed 87 92 S 5 7256 6380 2980 Blue 10
3 PM Wed 89 93 S 5 7748 6607 3207 Blue 11
4 PM Wed 89 91 S 5 6862 5812 2412 Blue 9
5 PM Wed 87 88 S 6 5872 3839 439 Blue 6
6 PM Wed 83 82 S 6 2875 3400 0 Blue 0
7 PM Wed 78 76 S 6 2635 3400 0 Blue 0
8 PM Wed 73 71 S 6 2635 3400 0 Blue 0
9 PM Wed 70 68 S 6 2635 3400 0 Blue 0
10 PM Wed 69 67 S 6 2635 3400 0 Blue 0
11 PM Wed 69 67 W 3 2635 3400 0 Blue 0
12 Midnight Thu 68 66 W 3 2635 3400 0 Blue 0
1 AM Thu 67 65 W 3 2635 3400 0 Blue 0
2 AM Thu 66 64 W 3 2635 3400 0 Blue 0
3 AM Thu 65 63 W 3 2635 3400 0 Blue 0
4 AM Thu 64 62 W 3 2635 3400 0 Blue 0
5 AM Thu 64 62 N 6 2635 3400 0 Blue 0
6 AM Thu 64 62 N 6 2635 3400 0 Blue 0
7 AM Thu 66 64 N 6 2635 3400 0 Blue 0
8 AM Thu 69 67 N 6 2635 3400 0 Blue 0
9 AM Thu 73 73 N 6 2635 3400 0 Blue 0
10 AM Thu 78 79 N 6 2635 3400 0 Blue 0
11 AM Thu 82 85 E 3 3864 3400 0 Blue 3
12 Noon Thu 85 90 E 3 6635 5183 1783 Blue 8
1 PM Thu 87 92 E 3 7256 6380 2980 Blue 10
2 PM Thu 88 93 E 3 7748 6607 3207 Blue 11
3 PM Thu 89 93 E 3 7748 6607 3207 Blue 11
4 PM Thu 89 92 E 3 7256 6380 2980 Blue 10
5 PM Thu 87 88 SW 6 5872 3839 439 Blue 6
6 PM Thu 83 82 SW 6 2875 3400 0 Blue 0
7 PM Thu 78 76 SW 6 2635 3400 0 Blue 0
8 PM Thu 74 72 SW 6 2635 3400 0 Blue 0
9 PM Thu 72 70 SW 6 2635 3400 0 Blue 0
10 PM Thu 70 68 SW 6 2635 3400 0 Blue 0
11 PM Thu 70 68 W 3 2635 3400 0 Blue 0
12 Midnight Fri 68 66 W 3 2635 3400 0 Blue 0
1 AM Fri 67 65 W 3 2635 3400 0 Blue 0
2 AM Fri 66 64 W 3 2635 3400 0 Blue 0
3 AM Fri 65 63 W 3 2635 3400 0 Blue 0
4 AM Fri 64 62 W 3 2635 3400 0 Blue 0
5 AM Fri 64 62 N 5 2635 3400 0 Blue 0
6 AM Fri 64 62 N 5 2635 3400 0 Blue 0
7 AM Fri 65 63 N 5 2635 3400 0 Blue 0
8 AM Fri 67 65 N 5 2635 3400 0 Blue 0
9 AM Fri 71 71 N 5 2635 3400 0 Blue 0
10 AM Fri 76 77 N 5 2635 3400 0 Blue 0
11 AM Fri 81 84 E 3 3473 3400 0 Blue 2
12 Noon Fri 84 88 E 3 5872 3839 439 Blue 6
1 PM Fri 87 92 E 3 7256 6380 2980 Blue 10
2 PM Fri 88 93 E 3 7748 6607 3207 Blue 11
3 PM Fri 89 93 E 3 7748 6607 3207 Blue 11
4 PM Fri 89 91 E 3 6862 5812 2412 Blue 9
5 PM Fri 87 88 SW 6 5872 3839 439 Blue 6
6 PM Fri 84 83 SW 6 3171 3400 0 Blue 1
7 PM Fri 79 77 SW 6 2635 3400 0 Blue 0
8 PM Fri 75 73 SW 6 2635 3400 0 Blue 0
9 PM Fri 73 71 SW 6 2635 3400 0 Blue 0
10 PM Fri 71 69 SW 6 2635 3400 0 Blue 0
11 PM Fri 70 68 W 2 2635 3400 0 Blue 0
12 Midnight Sat 69 67 W 2 2635 3400 0 Blue 0
1 AM Sat 67 65 W 2 2635 3400 0 Blue 0
2 AM Sat 66 64 W 2 2635 3400 0 Blue 0
3 AM Sat 65 63 W 2 2635 3400 0 Blue 0
4 AM Sat 64 62 W 2 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