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

Station:

KOAK

Date/Time:

26 APR 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 55 53 E 2 2592 3400 0 Blue 0
6 AM Thu 55 53 E 2 2592 3400 0 Blue 0
7 AM Thu 56 54 E 2 2592 3400 0 Blue 0
8 AM Thu 57 55 E 2 2592 3400 0 Blue 0
9 AM Thu 60 59 E 2 2636 3400 0 Blue 0
10 AM Thu 63 64 E 2 3086 3400 0 Blue 0
11 AM Thu 66 68 E 8 4525 3400 0 Blue 3
12 Noon Thu 68 71 E 8 5314 4501 1101 Blue 6
1 PM Thu 69 73 E 8 5721 5094 1694 Blue 8
2 PM Thu 70 73 SE 15 5721 5094 1694 Blue 8
3 PM Thu 70 72 SE 15 5518 4891 1491 Blue 7
4 PM Thu 70 71 SE 15 5314 4501 1101 Blue 6
5 PM Thu 68 68 S 6 4525 3400 0 Blue 3
6 PM Thu 65 63 S 6 2996 3400 0 Blue 0
7 PM Thu 61 59 S 6 2636 3400 0 Blue 0
8 PM Thu 57 55 S 5 2592 3400 0 Blue 0
9 PM Thu 54 52 S 5 2592 3400 0 Blue 0
10 PM Thu 52 50 S 5 2592 3400 0 Blue 0
11 PM Thu 51 49 W 3 2592 3400 0 Blue 0
12 Midnight Fri 50 48 W 3 2592 3400 0 Blue 0
1 AM Fri 50 48 W 3 2592 3400 0 Blue 0
2 AM Fri 49 47 W 5 2592 3400 0 Blue 0
3 AM Fri 48 46 W 5 2592 3400 0 Blue 0
4 AM Fri 47 45 W 5 2592 3400 0 Blue 0
5 AM Fri 46 44 W 6 2592 3400 0 Blue 0
6 AM Fri 45 43 W 6 2592 3400 0 Blue 0
7 AM Fri 45 43 W 6 2592 3400 0 Blue 0
8 AM Fri 47 45 S 2 2592 3400 0 Blue 0
9 AM Fri 49 48 S 2 2592 3400 0 Blue 0
10 AM Fri 52 53 S 2 2592 3400 0 Blue 0
11 AM Fri 54 55 S 6 2592 3400 0 Blue 0
12 Noon Fri 56 57 S 6 2592 3400 0 Blue 0
1 PM Fri 56 57 S 6 2592 3400 0 Blue 0
2 PM Fri 57 58 S 7 2592 3400 0 Blue 0
3 PM Fri 57 58 S 7 2592 3400 0 Blue 0
4 PM Fri 57 57 S 7 2592 3400 0 Blue 0
5 PM Fri 55 54 SW 10 2592 3400 0 Blue 0
6 PM Fri 53 51 SW 10 2592 3400 0 Blue 0
7 PM Fri 50 48 SW 10 2592 3400 0 Blue 0
8 PM Fri 47 45 SW 10 2592 3400 0 Blue 0
9 PM Fri 45 43 SW 10 2592 3400 0 Blue 0
10 PM Fri 44 42 SW 10 2592 3400 0 Blue 0
11 PM Fri 44 42 W 6 2592 3400 0 Blue 0
12 Midnight Sat 43 41 W 6 2592 3400 0 Blue 0
1 AM Sat 43 41 W 6 2592 3400 0 Blue 0
2 AM Sat 43 41 W 6 2592 3400 0 Blue 0
3 AM Sat 43 41 W 6 2592 3400 0 Blue 0
4 AM Sat 43 41 W 6 2592 3400 0 Blue 0
5 AM Sat 43 41 NW 3 2592 3400 0 Blue 0
6 AM Sat 43 41 NW 3 2592 3400 0 Blue 0
7 AM Sat 44 42 NW 3 2592 3400 0 Blue 0
8 AM Sat 45 43 NW 3 2592 3400 0 Blue 0
9 AM Sat 47 46 NW 3 2592 3400 0 Blue 0
10 AM Sat 49 48 NW 3 2592 3400 0 Blue 0
11 AM Sat 52 52 E 5 2592 3400 0 Blue 0
12 Noon Sat 53 54 E 5 2592 3400 0 Blue 0
1 PM Sat 54 55 E 5 2592 3400 0 Blue 0
2 PM Sat 55 56 E 5 2592 3400 0 Blue 0
3 PM Sat 56 57 E 5 2592 3400 0 Blue 0
4 PM Sat 56 56 E 5 2592 3400 0 Blue 0
5 PM Sat 55 54 SW 6 2592 3400 0 Blue 0
6 PM Sat 53 51 SW 6 2592 3400 0 Blue 0
7 PM Sat 51 49 SW 6 2592 3400 0 Blue 0
8 PM Sat 49 47 SW 6 2592 3400 0 Blue 0
9 PM Sat 47 45 SW 6 2592 3400 0 Blue 0
10 PM Sat 46 44 SW 6 2592 3400 0 Blue 0
11 PM Sat 46 44 W 6 2592 3400 0 Blue 0
12 Midnight Sun 45 43 W 6 2592 3400 0 Blue 0
1 AM Sun 45 43 W 6 2592 3400 0 Blue 0
2 AM Sun 45 43 W 6 2592 3400 0 Blue 0
3 AM Sun 44 42 W 6 2592 3400 0 Blue 0
4 AM Sun 44 42 W 6 2592 3400 0 Blue 0
5 AM Sun 44 42 W 5 2592 3400 0 Blue 0
6 AM Sun 44 42 W 5 2592 3400 0 Blue 0
7 AM Sun 45 43 W 5 2592 3400 0 Blue 0
8 AM Sun 47 45 W 5 2592 3400 0 Blue 0
9 AM Sun 50 49 W 5 2592 3400 0 Blue 0
10 AM Sun 53 53 W 5 2592 3400 0 Blue 0
11 AM Sun 56 56 W 5 2592 3400 0 Blue 0
12 Noon Sun 58 59 W 5 2636 3400 0 Blue 0
1 PM Sun 59 60 W 5 2726 3400 0 Blue 0
2 PM Sun 60 61 W 5 2816 3400 0 Blue 0
3 PM Sun 60 60 W 5 2726 3400 0 Blue 0
4 PM Sun 60 60 W 5 2726 3400 0 Blue 0
5 PM Sun 59 58 W 8 2592 3400 0 Blue 0
6 PM Sun 56 54 W 8 2592 3400 0 Blue 0
7 PM Sun 53 51 W 8 2592 3400 0 Blue 0
8 PM Sun 50 48 W 8 2592 3400 0 Blue 0
9 PM Sun 49 47 W 8 2592 3400 0 Blue 0
10 PM Sun 48 46 W 8 2592 3400 0 Blue 0
11 PM Sun 47 45 NW 5 2592 3400 0 Blue 0
12 Midnight Mon 47 45 NW 5 2592 3400 0 Blue 0
1 AM Mon 46 44 NW 5 2592 3400 0 Blue 0
2 AM Mon 45 43 NW 5 2592 3400 0 Blue 0
3 AM Mon 44 42 NW 5 2592 3400 0 Blue 0
4 AM Mon 44 42 NW 5 2592 3400 0 Blue 0
5 AM Mon 44 42 NW 5 2592 3400 0 Blue 0
6 AM Mon 45 43 NW 5 2592 3400 0 Blue 0
7 AM Mon 46 44 NW 5 2592 3400 0 Blue 0
8 AM Mon 49 47 NW 5 2592 3400 0 Blue 0
9 AM Mon 52 51 NW 5 2592 3400 0 Blue 0
10 AM Mon 56 56 NW 5 2592 3400 0 Blue 0
11 AM Mon 60 62 N 2 2906 3400 0 Blue 0
12 Noon Mon 62 65 N 2 3214 3400 0 Blue 0
1 PM Mon 64 67 N 2 4096 3400 0 Blue 2
2 PM Mon 65 68 N 2 4525 3400 0 Blue 3
3 PM Mon 66 68 N 2 4525 3400 0 Blue 3
4 PM Mon 66 67 N 2 4096 3400 0 Blue 2
5 PM Mon 64 64 W 5 3086 3400 0 Blue 0
6 PM Mon 61 59 W 5 2636 3400 0 Blue 0
7 PM Mon 57 55 W 5 2592 3400 0 Blue 0
8 PM Mon 53 51 W 5 2592 3400 0 Blue 0
9 PM Mon 50 48 W 5 2592 3400 0 Blue 0
10 PM Mon 49 47 W 5 2592 3400 0 Blue 0
11 PM Mon 47 45 NW 5 2592 3400 0 Blue 0
12 Midnight Tue 47 45 NW 5 2592 3400 0 Blue 0
1 AM Tue 46 44 NW 5 2592 3400 0 Blue 0
2 AM Tue 45 43 NW 5 2592 3400 0 Blue 0
3 AM Tue 45 43 NW 5 2592 3400 0 Blue 0
4 AM Tue 45 43 NW 5 2592 3400 0 Blue 0
5 AM Tue 45 43 N 7 2592 3400 0 Blue 0
6 AM Tue 46 44 N 7 2592 3400 0 Blue 0
7 AM Tue 48 46 N 7 2592 3400 0 Blue 0
8 AM Tue 50 48 N 7 2592 3400 0 Blue 0
9 AM Tue 55 55 N 7 2592 3400 0 Blue 0
10 AM Tue 60 61 N 7 2816 3400 0 Blue 0
11 AM Tue 65 68 N 7 4525 3400 0 Blue 3
12 Noon Tue 68 72 N 7 5518 4891 1491 Blue 7
1 PM Tue 70 74 N 7 5924 5297 1897 Blue 9
2 PM Tue 71 75 N 7 6716 5500 2100 Blue 10
3 PM Tue 72 75 N 7 6716 5500 2100 Blue 10
4 PM Tue 72 73 N 7 5721 5094 1694 Blue 8
5 PM Tue 71 71 N 3 5314 4501 1101 Blue 6
6 PM Tue 68 66 N 3 3659 3400 0 Blue 1
7 PM Tue 64 62 N 3 2906 3400 0 Blue 0
8 PM Tue 60 58 N 3 2592 3400 0 Blue 0
9 PM Tue 58 56 N 3 2592 3400 0 Blue 0
10 PM Tue 57 55 N 3 2592 3400 0 Blue 0
11 PM Tue 56 54 NW 5 2592 3400 0 Blue 0
12 Midnight Wed 55 53 NW 5 2592 3400 0 Blue 0
1 AM Wed 54 52 NW 5 2592 3400 0 Blue 0
2 AM Wed 53 51 NW 5 2592 3400 0 Blue 0
3 AM Wed 51 49 NW 5 2592 3400 0 Blue 0
4 AM Wed 50 48 NW 5 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