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

Station:

KOAK

Date/Time:

18 OCT 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 Fri 48 46 W 7 2625 3400 0 Blue 0
6 AM Fri 49 47 W 7 2625 3400 0 Blue 0
7 AM Fri 48 46 W 7 2625 3400 0 Blue 0
8 AM Fri 52 50 W 6 2625 3400 0 Blue 0
9 AM Fri 57 55 W 6 3253 3400 0 Blue 2
10 AM Fri 60 58 W 6 3577 3400 0 Blue 5
11 AM Fri 61 61 W 3 4797 3574 174 Blue 8
12 Noon Fri 64 65 W 3 6720 5275 1875 Blue 12
1 PM Fri 66 67 W 3 7377 6212 2812 Blue 14
2 PM Fri 68 69 SW 5 7873 7092 3692 Blue 16
3 PM Fri 68 68 SW 5 7626 6662 3262 Blue 15
4 PM Fri 68 67 SW 5 7377 6212 2812 Blue 14
5 PM Fri 66 64 W 5 6264 4758 1358 Blue 11
6 PM Fri 56 54 W 5 3146 3400 0 Blue 1
7 PM Fri 53 51 W 5 2625 3400 0 Blue 0
8 PM Fri 53 51 W 5 2625 3400 0 Blue 0
9 PM Fri 51 49 W 5 2625 3400 0 Blue 0
10 PM Fri 51 49 W 5 2625 3400 0 Blue 0
11 PM Fri 53 51 W 6 2625 3400 0 Blue 0
12 Midnight Sat 51 49 W 6 2625 3400 0 Blue 0
1 AM Sat 53 51 W 6 2625 3400 0 Blue 0
2 AM Sat 53 51 W 7 2625 3400 0 Blue 0
3 AM Sat 51 49 W 7 2625 3400 0 Blue 0
4 AM Sat 50 48 W 7 2625 3400 0 Blue 0
5 AM Sat 50 48 W 8 2625 3400 0 Blue 0
6 AM Sat 50 48 W 8 2625 3400 0 Blue 0
7 AM Sat 49 47 W 8 2625 3400 0 Blue 0
8 AM Sat 54 52 W 8 2625 3400 0 Blue 0
9 AM Sat 58 56 W 8 3361 3400 0 Blue 3
10 AM Sat 60 58 W 8 3577 3400 0 Blue 5
11 AM Sat 61 60 W 7 4304 3466 66 Blue 7
12 Noon Sat 63 62 W 7 5315 3870 470 Blue 9
1 PM Sat 65 64 W 7 6264 4758 1358 Blue 11
2 PM Sat 65 64 W 7 6264 4758 1358 Blue 11
3 PM Sat 66 65 W 7 6720 5275 1875 Blue 12
4 PM Sat 66 64 W 7 6264 4758 1358 Blue 11
5 PM Sat 64 62 NW 7 5315 3870 470 Blue 9
6 PM Sat 60 58 NW 7 3577 3400 0 Blue 5
7 PM Sat 55 53 NW 7 3025 3400 0 Blue 0
8 PM Sat 52 50 NW 7 2625 3400 0 Blue 0
9 PM Sat 50 48 NW 7 2625 3400 0 Blue 0
10 PM Sat 50 48 NW 7 2625 3400 0 Blue 0
11 PM Sat 50 48 NW 5 2625 3400 0 Blue 0
12 Midnight Sun 50 48 NW 5 2625 3400 0 Blue 0
1 AM Sun 50 48 NW 5 2625 3400 0 Blue 0
2 AM Sun 49 47 NW 5 2625 3400 0 Blue 0
3 AM Sun 49 47 NW 5 2625 3400 0 Blue 0
4 AM Sun 48 46 NW 5 2625 3400 0 Blue 0
5 AM Sun 48 46 NW 6 2625 3400 0 Blue 0
6 AM Sun 48 46 NW 6 2625 3400 0 Blue 0
7 AM Sun 49 47 NW 6 2625 3400 0 Blue 0
8 AM Sun 51 49 NW 6 2625 3400 0 Blue 0
9 AM Sun 54 52 NW 6 2625 3400 0 Blue 0
10 AM Sun 58 56 NW 6 3361 3400 0 Blue 3
11 AM Sun 61 60 NW 6 4304 3466 66 Blue 7
12 Noon Sun 64 64 NW 6 6264 4758 1358 Blue 11
1 PM Sun 65 65 NW 6 6720 5275 1875 Blue 12
2 PM Sun 66 66 NW 6 7128 5750 2350 Blue 13
3 PM Sun 67 66 NW 6 7128 5750 2350 Blue 13
4 PM Sun 67 66 NW 6 7128 5750 2350 Blue 13
5 PM Sun 65 63 NW 7 5797 4283 883 Blue 10
6 PM Sun 62 60 NW 7 4304 3466 66 Blue 7
7 PM Sun 58 56 NW 7 3361 3400 0 Blue 3
8 PM Sun 55 53 NW 7 3025 3400 0 Blue 0
9 PM Sun 54 52 NW 7 2625 3400 0 Blue 0
10 PM Sun 54 52 NW 7 2625 3400 0 Blue 0
11 PM Sun 54 52 NW 7 2625 3400 0 Blue 0
12 Midnight Mon 54 52 NW 7 2625 3400 0 Blue 0
1 AM Mon 54 52 NW 7 2625 3400 0 Blue 0
2 AM Mon 54 52 NW 7 2625 3400 0 Blue 0
3 AM Mon 54 52 NW 7 2625 3400 0 Blue 0
4 AM Mon 54 52 NW 7 2625 3400 0 Blue 0
5 AM Mon 54 52 N 7 2625 3400 0 Blue 0
6 AM Mon 54 52 N 7 2625 3400 0 Blue 0
7 AM Mon 55 53 N 7 3025 3400 0 Blue 0
8 AM Mon 57 55 N 7 3253 3400 0 Blue 2
9 AM Mon 60 58 N 7 3577 3400 0 Blue 5
10 AM Mon 64 63 N 7 5797 4283 883 Blue 10
11 AM Mon 68 68 N 7 7626 6662 3262 Blue 15
12 Noon Mon 70 71 N 7 8364 7586 4186 Blue 18
1 PM Mon 72 74 N 7 9080 8318 4918 Blue 21
2 PM Mon 73 74 N 7 9080 8318 4918 Blue 21
3 PM Mon 74 74 N 7 9080 8318 4918 Blue 21
4 PM Mon 74 73 N 7 8834 8075 4675 Blue 20
5 PM Mon 72 70 NW 6 8119 7339 3939 Blue 17
6 PM Mon 69 67 NW 6 7377 6212 2812 Blue 14
7 PM Mon 65 63 NW 6 5797 4283 883 Blue 10
8 PM Mon 62 60 NW 6 4304 3466 66 Blue 7
9 PM Mon 60 58 NW 6 3577 3400 0 Blue 5
10 PM Mon 60 58 NW 6 3577 3400 0 Blue 5
11 PM Mon 61 59 N 6 3886 3400 0 Blue 6
12 Midnight Tue 60 58 N 6 3577 3400 0 Blue 5
1 AM Tue 59 57 N 6 3469 3400 0 Blue 4
2 AM Tue 58 56 N 6 3361 3400 0 Blue 3
3 AM Tue 57 55 N 6 3253 3400 0 Blue 2
4 AM Tue 57 55 N 6 3253 3400 0 Blue 2
5 AM Tue 57 55 N 6 3253 3400 0 Blue 2
6 AM Tue 57 55 N 6 3253 3400 0 Blue 2
7 AM Tue 58 56 N 6 3361 3400 0 Blue 3
8 AM Tue 61 59 N 6 3886 3400 0 Blue 6
9 AM Tue 65 63 N 6 5797 4283 883 Blue 10
10 AM Tue 71 70 N 6 8119 7339 3939 Blue 17
11 AM Tue 76 76 N 6 9945 8790 5390 Blue 23
12 Noon Tue 79 80 N 6 11887 10397 6997 White 27
1 PM Tue 81 83 N 6 12501 12222 8822 White 30
2 PM Tue 82 83 N 6 12501 12222 8822 White 30
3 PM Tue 83 83 N 6 12501 12222 8822 White 30
4 PM Tue 82 81 N 6 12092 11034 7634 White 28
5 PM Tue 80 78 NW 6 11210 9360 5960 Blue 25
6 PM Tue 74 72 NW 6 8607 7831 4431 Blue 19
7 PM Tue 68 66 NW 6 7128 5750 2350 Blue 13
8 PM Tue 63 61 NW 6 4797 3574 174 Blue 8
9 PM Tue 61 59 NW 6 3886 3400 0 Blue 6
10 PM Tue 61 59 NW 6 3886 3400 0 Blue 6
11 PM Tue 62 60 N 7 4304 3466 66 Blue 7
12 Midnight Wed 61 59 N 7 3886 3400 0 Blue 6
1 AM Wed 60 58 N 7 3577 3400 0 Blue 5
2 AM Wed 59 57 N 7 3469 3400 0 Blue 4
3 AM Wed 58 56 N 7 3361 3400 0 Blue 3
4 AM Wed 57 55 N 7 3253 3400 0 Blue 2
5 AM Wed 56 54 N 9 3146 3400 0 Blue 1
6 AM Wed 56 54 N 9 3146 3400 0 Blue 1
7 AM Wed 57 55 N 9 3253 3400 0 Blue 2
8 AM Wed 59 57 N 9 3469 3400 0 Blue 4
9 AM Wed 63 61 N 9 4797 3574 174 Blue 8
10 AM Wed 68 67 N 9 7377 6212 2812 Blue 14
11 AM Wed 72 72 N 10 8607 7831 4431 Blue 19
12 Noon Wed 76 77 N 10 10568 9006 5606 Blue 24
1 PM Wed 79 81 N 10 12092 11034 7634 White 28
2 PM Wed 80 81 N 10 12092 11034 7634 White 28
3 PM Wed 81 81 N 10 12092 11034 7634 White 28
4 PM Wed 80 79 N 10 11681 9816 6416 White 26
5 PM Wed 78 76 N 10 9945 8790 5390 Blue 23
6 PM Wed 73 71 N 10 8364 7586 4186 Blue 18
7 PM Wed 67 65 N 10 6720 5275 1875 Blue 12
8 PM Wed 63 61 N 10 4797 3574 174 Blue 8
9 PM Wed 61 59 N 10 3886 3400 0 Blue 6
10 PM Wed 61 59 N 10 3886 3400 0 Blue 6
11 PM Wed 62 60 N 12 4304 3466 66 Blue 7
12 Midnight Thu 62 60 N 12 4304 3466 66 Blue 7
1 AM Thu 61 59 N 12 3886 3400 0 Blue 6
2 AM Thu 59 57 N 12 3469 3400 0 Blue 4
3 AM Thu 58 56 N 12 3361 3400 0 Blue 3
4 AM Thu 56 54 N 12 3146 3400 0 Blue 1

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