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

Station:

KOAK

Date/Time:

16 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 Thu 66 64 N 2 2592 3400 0 Blue 0
6 AM Thu 67 65 N 2 2592 3400 0 Blue 0
7 AM Thu 68 66 N 2 2592 3400 0 Blue 0
8 AM Thu 71 69 N 2 2592 3400 0 Blue 0
9 AM Thu 76 75 N 2 2660 3400 0 Blue 0
10 AM Thu 80 81 N 2 3786 3400 0 Blue 3
11 AM Thu 84 87 E 3 6936 5189 1789 Blue 9
12 Noon Thu 87 91 E 3 9325 7776 4376 Blue 13
1 PM Thu 89 94 E 3 11457 9229 5829 Blue 16
2 PM Thu 90 95 SE 10 12343 9680 6280 Blue 17
3 PM Thu 91 95 SE 10 12343 9680 6280 Blue 17
4 PM Thu 91 93 SE 10 10465 8768 5368 Blue 15
5 PM Thu 90 91 S 7 9325 7776 4376 Blue 13
6 PM Thu 86 85 S 7 5704 3996 596 Blue 7
7 PM Thu 81 79 S 7 3346 3400 0 Blue 1
8 PM Thu 77 75 SW 5 2660 3400 0 Blue 0
9 PM Thu 74 72 SW 5 2592 3400 0 Blue 0
10 PM Thu 73 71 SW 5 2592 3400 0 Blue 0
11 PM Thu 72 70 W 3 2592 3400 0 Blue 0
12 Midnight Fri 71 69 W 3 2592 3400 0 Blue 0
1 AM Fri 71 69 W 3 2592 3400 0 Blue 0
2 AM Fri 70 68 N 3 2592 3400 0 Blue 0
3 AM Fri 69 67 N 3 2592 3400 0 Blue 0
4 AM Fri 68 66 N 3 2592 3400 0 Blue 0
5 AM Fri 67 65 N 3 2592 3400 0 Blue 0
6 AM Fri 67 65 N 3 2592 3400 0 Blue 0
7 AM Fri 68 66 N 3 2592 3400 0 Blue 0
8 AM Fri 70 68 N 3 2592 3400 0 Blue 0
9 AM Fri 75 75 N 3 2660 3400 0 Blue 0
10 AM Fri 80 81 N 3 3786 3400 0 Blue 3
11 AM Fri 85 88 E 6 7859 5661 2261 Blue 10
12 Noon Fri 88 92 E 6 9781 8287 4887 Blue 14
1 PM Fri 90 95 E 6 12343 9680 6280 Blue 17
2 PM Fri 91 96 E 6 13151 10281 6881 Blue 18
3 PM Fri 92 96 E 6 13151 10281 6881 Blue 18
4 PM Fri 92 94 E 6 11457 9229 5829 Blue 16
5 PM Fri 91 92 SE 7 9781 8287 4887 Blue 14
6 PM Fri 87 86 SE 7 6172 4213 813 Blue 8
7 PM Fri 82 80 SE 7 3566 3400 0 Blue 2
8 PM Fri 77 75 SE 7 2660 3400 0 Blue 0
9 PM Fri 74 72 SE 7 2592 3400 0 Blue 0
10 PM Fri 72 70 SE 7 2592 3400 0 Blue 0
11 PM Fri 72 70 N 3 2592 3400 0 Blue 0
12 Midnight Sat 71 69 N 3 2592 3400 0 Blue 0
1 AM Sat 70 68 N 3 2592 3400 0 Blue 0
2 AM Sat 69 67 N 3 2592 3400 0 Blue 0
3 AM Sat 68 66 N 3 2592 3400 0 Blue 0
4 AM Sat 67 65 N 3 2592 3400 0 Blue 0
5 AM Sat 67 65 N 3 2592 3400 0 Blue 0
6 AM Sat 67 65 N 3 2592 3400 0 Blue 0
7 AM Sat 69 67 N 3 2592 3400 0 Blue 0
8 AM Sat 72 70 N 3 2592 3400 0 Blue 0
9 AM Sat 78 78 N 3 3095 3400 0 Blue 0
10 AM Sat 84 85 N 3 5704 3996 596 Blue 7
11 AM Sat 89 92 E 3 9781 8287 4887 Blue 14
12 Noon Sat 92 97 E 3 13881 11198 7798 Blue 19
1 PM Sat 94 99 E 3 14827 12889 9489 Blue 21
2 PM Sat 95 100 E 3 15474 13637 10237 Blue 22
3 PM Sat 96 100 E 3 15474 13637 10237 Blue 22
4 PM Sat 96 99 E 3 14827 12889 9489 Blue 21
5 PM Sat 94 95 S 5 12343 9680 6280 Blue 17
6 PM Sat 91 90 S 5 8858 6743 3343 Blue 12
7 PM Sat 86 84 S 5 5226 3779 379 Blue 6
8 PM Sat 81 79 S 5 3346 3400 0 Blue 1
9 PM Sat 78 76 S 5 2763 3400 0 Blue 0
10 PM Sat 76 74 S 5 2592 3400 0 Blue 0
11 PM Sat 74 72 NW 3 2592 3400 0 Blue 0
12 Midnight Sun 73 71 NW 3 2592 3400 0 Blue 0
1 AM Sun 72 70 NW 3 2592 3400 0 Blue 0
2 AM Sun 71 69 NW 3 2592 3400 0 Blue 0
3 AM Sun 70 68 NW 3 2592 3400 0 Blue 0
4 AM Sun 69 67 NW 3 2592 3400 0 Blue 0
5 AM Sun 69 67 NE 5 2592 3400 0 Blue 0
6 AM Sun 69 67 NE 5 2592 3400 0 Blue 0
7 AM Sun 70 68 NE 5 2592 3400 0 Blue 0
8 AM Sun 73 71 NE 5 2592 3400 0 Blue 0
9 AM Sun 77 77 NE 5 2866 3400 0 Blue 0
10 AM Sun 82 83 NE 5 4223 3560 160 Blue 5
11 AM Sun 86 89 SE 3 8376 6123 2723 Blue 11
12 Noon Sun 89 94 SE 3 11457 9229 5829 Blue 16
1 PM Sun 91 96 SE 3 13151 10281 6881 Blue 18
2 PM Sun 92 97 SE 3 13881 11198 7798 Blue 19
3 PM Sun 93 97 SE 3 13881 11198 7798 Blue 19
4 PM Sun 93 96 SE 3 13151 10281 6881 Blue 18
5 PM Sun 91 92 SW 7 9781 8287 4887 Blue 14
6 PM Sun 87 86 SW 7 6172 4213 813 Blue 8
7 PM Sun 82 80 SW 7 3566 3400 0 Blue 2
8 PM Sun 78 76 SW 7 2763 3400 0 Blue 0
9 PM Sun 75 73 SW 7 2592 3400 0 Blue 0
10 PM Sun 73 71 SW 7 2592 3400 0 Blue 0
11 PM Sun 72 70 W 3 2592 3400 0 Blue 0
12 Midnight Mon 71 69 W 3 2592 3400 0 Blue 0
1 AM Mon 71 69 W 3 2592 3400 0 Blue 0
2 AM Mon 70 68 W 3 2592 3400 0 Blue 0
3 AM Mon 69 67 W 3 2592 3400 0 Blue 0
4 AM Mon 69 67 W 3 2592 3400 0 Blue 0
5 AM Mon 68 66 N 6 2592 3400 0 Blue 0
6 AM Mon 68 66 N 6 2592 3400 0 Blue 0
7 AM Mon 69 67 N 6 2592 3400 0 Blue 0
8 AM Mon 71 69 N 6 2592 3400 0 Blue 0
9 AM Mon 75 75 N 6 2660 3400 0 Blue 0
10 AM Mon 80 81 N 6 3786 3400 0 Blue 3
11 AM Mon 85 88 E 6 7859 5661 2261 Blue 10
12 Noon Mon 88 93 E 6 10465 8768 5368 Blue 15
1 PM Mon 90 95 E 6 12343 9680 6280 Blue 17
2 PM Mon 91 96 E 6 13151 10281 6881 Blue 18
3 PM Mon 92 96 E 6 13151 10281 6881 Blue 18
4 PM Mon 92 95 E 6 12343 9680 6280 Blue 17
5 PM Mon 90 91 S 7 9325 7776 4376 Blue 13
6 PM Mon 87 86 S 7 6172 4213 813 Blue 8
7 PM Mon 83 81 S 7 3786 3400 0 Blue 3
8 PM Mon 79 77 S 7 2866 3400 0 Blue 0
9 PM Mon 77 75 S 7 2660 3400 0 Blue 0
10 PM Mon 75 73 S 7 2592 3400 0 Blue 0
11 PM Mon 74 72 NW 3 2592 3400 0 Blue 0
12 Midnight Tue 73 71 NW 3 2592 3400 0 Blue 0
1 AM Tue 72 70 NW 3 2592 3400 0 Blue 0
2 AM Tue 71 69 NW 3 2592 3400 0 Blue 0
3 AM Tue 70 68 NW 3 2592 3400 0 Blue 0
4 AM Tue 70 68 NW 3 2592 3400 0 Blue 0
5 AM Tue 69 67 NE 5 2592 3400 0 Blue 0
6 AM Tue 69 67 NE 5 2592 3400 0 Blue 0
7 AM Tue 70 68 NE 5 2592 3400 0 Blue 0
8 AM Tue 73 71 NE 5 2592 3400 0 Blue 0
9 AM Tue 77 77 NE 5 2866 3400 0 Blue 0
10 AM Tue 81 82 NE 5 4005 3400 0 Blue 4
11 AM Tue 86 89 E 5 8376 6123 2723 Blue 11
12 Noon Tue 89 94 E 5 11457 9229 5829 Blue 16
1 PM Tue 91 96 E 5 13151 10281 6881 Blue 18
2 PM Tue 92 97 E 5 13881 11198 7798 Blue 19
3 PM Tue 93 97 E 5 13881 11198 7798 Blue 19
4 PM Tue 93 96 E 5 13151 10281 6881 Blue 18
5 PM Tue 91 92 S 7 9781 8287 4887 Blue 14
6 PM Tue 88 87 S 7 6936 5189 1789 Blue 9
7 PM Tue 83 81 S 7 3786 3400 0 Blue 3
8 PM Tue 79 77 S 7 2866 3400 0 Blue 0
9 PM Tue 77 75 S 7 2660 3400 0 Blue 0
10 PM Tue 75 73 S 7 2592 3400 0 Blue 0
11 PM Tue 75 73 W 3 2592 3400 0 Blue 0
12 Midnight Wed 74 72 W 3 2592 3400 0 Blue 0
1 AM Wed 73 71 W 3 2592 3400 0 Blue 0
2 AM Wed 72 70 W 3 2592 3400 0 Blue 0
3 AM Wed 71 69 W 3 2592 3400 0 Blue 0
4 AM Wed 70 68 W 3 2592 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