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

Station:

KOAK

Date/Time:

25 APR 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 Thu 62 60 W 3 2628 3400 0 Blue 0
6 AM Thu 58 56 W 3 2628 3400 0 Blue 0
7 AM Thu 59 57 W 3 2628 3400 0 Blue 0
8 AM Thu 61 60 NW 2 2628 3400 0 Blue 0
9 AM Thu 66 66 NW 2 2628 3400 0 Blue 0
10 AM Thu 72 74 NW 2 2934 3400 0 Blue 0
11 AM Thu 77 80 E 3 7049 3449 49 Blue 5
12 Noon Thu 80 84 E 3 10149 7871 4471 Blue 9
1 PM Thu 81 85 E 3 11424 8679 5279 Blue 10
2 PM Thu 81 85 SE 5 11424 8679 5279 Blue 10
3 PM Thu 82 85 SE 5 11424 8679 5279 Blue 10
4 PM Thu 83 84 SE 5 10149 7871 4471 Blue 9
5 PM Thu 83 82 SW 7 8814 4916 1516 Blue 7
6 PM Thu 80 78 SW 7 4050 3400 0 Blue 3
7 PM Thu 77 75 SW 7 3064 3400 0 Blue 0
8 PM Thu 74 72 SW 6 2672 3400 0 Blue 0
9 PM Thu 71 69 SW 6 2628 3400 0 Blue 0
10 PM Thu 69 67 SW 6 2628 3400 0 Blue 0
11 PM Thu 68 66 W 5 2628 3400 0 Blue 0
12 Midnight Fri 66 64 W 5 2628 3400 0 Blue 0
1 AM Fri 65 63 W 5 2628 3400 0 Blue 0
2 AM Fri 63 61 NW 3 2628 3400 0 Blue 0
3 AM Fri 61 59 NW 3 2628 3400 0 Blue 0
4 AM Fri 59 57 NW 3 2628 3400 0 Blue 0
5 AM Fri 58 56 N 5 2628 3400 0 Blue 0
6 AM Fri 58 56 N 5 2628 3400 0 Blue 0
7 AM Fri 59 57 N 5 2628 3400 0 Blue 0
8 AM Fri 62 60 N 3 2628 3400 0 Blue 0
9 AM Fri 66 66 N 3 2628 3400 0 Blue 0
10 AM Fri 70 71 N 3 2628 3400 0 Blue 0
11 AM Fri 74 77 NE 5 3454 3400 0 Blue 2
12 Noon Fri 77 81 NE 5 8024 4012 612 Blue 6
1 PM Fri 78 82 NE 5 8814 4916 1516 Blue 7
2 PM Fri 79 83 E 5 9499 6911 3511 Blue 8
3 PM Fri 80 83 E 5 9499 6911 3511 Blue 8
4 PM Fri 80 81 E 5 8024 4012 612 Blue 6
5 PM Fri 79 79 E 3 5002 3400 0 Blue 4
6 PM Fri 76 74 E 3 2934 3400 0 Blue 0
7 PM Fri 73 71 E 3 2628 3400 0 Blue 0
8 PM Fri 70 68 E 3 2628 3400 0 Blue 0
9 PM Fri 67 65 E 3 2628 3400 0 Blue 0
10 PM Fri 66 64 E 3 2628 3400 0 Blue 0
11 PM Fri 65 63 W 5 2628 3400 0 Blue 0
12 Midnight Sat 64 62 W 5 2628 3400 0 Blue 0
1 AM Sat 63 61 W 5 2628 3400 0 Blue 0
2 AM Sat 62 60 W 5 2628 3400 0 Blue 0
3 AM Sat 60 58 W 5 2628 3400 0 Blue 0
4 AM Sat 59 57 W 5 2628 3400 0 Blue 0
5 AM Sat 59 57 NW 5 2628 3400 0 Blue 0
6 AM Sat 58 56 NW 5 2628 3400 0 Blue 0
7 AM Sat 58 56 NW 5 2628 3400 0 Blue 0
8 AM Sat 60 58 NW 5 2628 3400 0 Blue 0
9 AM Sat 64 64 NW 5 2628 3400 0 Blue 0
10 AM Sat 68 69 NW 5 2628 3400 0 Blue 0
11 AM Sat 72 75 E 5 3064 3400 0 Blue 0
12 Noon Sat 74 78 E 5 4050 3400 0 Blue 3
1 PM Sat 75 80 E 5 7049 3449 49 Blue 5
2 PM Sat 75 79 E 5 5002 3400 0 Blue 4
3 PM Sat 76 79 E 5 5002 3400 0 Blue 4
4 PM Sat 76 78 E 5 4050 3400 0 Blue 3
5 PM Sat 75 75 SW 6 3064 3400 0 Blue 0
6 PM Sat 73 71 SW 6 2628 3400 0 Blue 0
7 PM Sat 71 69 SW 6 2628 3400 0 Blue 0
8 PM Sat 68 66 SW 6 2628 3400 0 Blue 0
9 PM Sat 66 64 SW 6 2628 3400 0 Blue 0
10 PM Sat 64 62 SW 6 2628 3400 0 Blue 0
11 PM Sat 63 61 NW 5 2628 3400 0 Blue 0
12 Midnight Sun 62 60 NW 5 2628 3400 0 Blue 0
1 AM Sun 61 59 NW 5 2628 3400 0 Blue 0
2 AM Sun 59 57 NW 5 2628 3400 0 Blue 0
3 AM Sun 58 56 NW 5 2628 3400 0 Blue 0
4 AM Sun 57 55 NW 5 2628 3400 0 Blue 0
5 AM Sun 56 54 NE 6 2628 3400 0 Blue 0
6 AM Sun 56 54 NE 6 2628 3400 0 Blue 0
7 AM Sun 57 55 NE 6 2628 3400 0 Blue 0
8 AM Sun 60 58 NE 6 2628 3400 0 Blue 0
9 AM Sun 63 63 NE 6 2628 3400 0 Blue 0
10 AM Sun 67 68 NE 6 2628 3400 0 Blue 0
11 AM Sun 70 73 SE 5 2803 3400 0 Blue 0
12 Noon Sun 73 77 SE 5 3454 3400 0 Blue 2
1 PM Sun 74 78 SE 5 4050 3400 0 Blue 3
2 PM Sun 75 79 SE 5 5002 3400 0 Blue 4
3 PM Sun 75 78 SE 5 4050 3400 0 Blue 3
4 PM Sun 75 76 SE 5 3241 3400 0 Blue 1
5 PM Sun 74 74 S 6 2934 3400 0 Blue 0
6 PM Sun 72 70 S 6 2628 3400 0 Blue 0
7 PM Sun 69 67 S 6 2628 3400 0 Blue 0
8 PM Sun 66 64 S 6 2628 3400 0 Blue 0
9 PM Sun 64 62 S 6 2628 3400 0 Blue 0
10 PM Sun 62 60 S 6 2628 3400 0 Blue 0
11 PM Sun 61 59 W 3 2628 3400 0 Blue 0
12 Midnight Mon 59 57 W 3 2628 3400 0 Blue 0
1 AM Mon 58 56 W 3 2628 3400 0 Blue 0
2 AM Mon 57 55 W 3 2628 3400 0 Blue 0
3 AM Mon 56 54 W 3 2628 3400 0 Blue 0
4 AM Mon 55 53 W 3 2628 3400 0 Blue 0
5 AM Mon 54 52 NE 3 2628 3400 0 Blue 0
6 AM Mon 54 52 NE 3 2628 3400 0 Blue 0
7 AM Mon 55 53 NE 3 2628 3400 0 Blue 0
8 AM Mon 58 56 NE 3 2628 3400 0 Blue 0
9 AM Mon 62 62 NE 3 2628 3400 0 Blue 0
10 AM Mon 67 68 NE 3 2628 3400 0 Blue 0
11 AM Mon 71 74 SE 5 2934 3400 0 Blue 0
12 Noon Mon 74 78 SE 5 4050 3400 0 Blue 3
1 PM Mon 74 78 SE 5 4050 3400 0 Blue 3
2 PM Mon 75 79 SE 5 5002 3400 0 Blue 4
3 PM Mon 76 79 SE 5 5002 3400 0 Blue 4
4 PM Mon 76 78 SE 5 4050 3400 0 Blue 3
5 PM Mon 75 75 SW 7 3064 3400 0 Blue 0
6 PM Mon 73 71 SW 7 2628 3400 0 Blue 0
7 PM Mon 69 67 SW 7 2628 3400 0 Blue 0
8 PM Mon 66 64 SW 7 2628 3400 0 Blue 0
9 PM Mon 63 61 SW 7 2628 3400 0 Blue 0
10 PM Mon 61 59 SW 7 2628 3400 0 Blue 0
11 PM Mon 59 57 W 7 2628 3400 0 Blue 0
12 Midnight Tue 57 55 W 7 2628 3400 0 Blue 0
1 AM Tue 55 53 W 7 2628 3400 0 Blue 0
2 AM Tue 53 51 W 7 2628 3400 0 Blue 0
3 AM Tue 52 50 W 7 2628 3400 0 Blue 0
4 AM Tue 50 48 W 7 2628 3400 0 Blue 0
5 AM Tue 50 48 W 7 2628 3400 0 Blue 0
6 AM Tue 50 48 W 7 2628 3400 0 Blue 0
7 AM Tue 52 50 W 7 2628 3400 0 Blue 0
8 AM Tue 54 52 W 7 2628 3400 0 Blue 0
9 AM Tue 57 57 W 7 2628 3400 0 Blue 0
10 AM Tue 61 62 W 7 2628 3400 0 Blue 0
11 AM Tue 64 67 NW 8 2628 3400 0 Blue 0
12 Noon Tue 66 70 NW 8 2628 3400 0 Blue 0
1 PM Tue 68 72 NW 8 2672 3400 0 Blue 0
2 PM Tue 69 73 NW 8 2803 3400 0 Blue 0
3 PM Tue 70 73 NW 8 2803 3400 0 Blue 0
4 PM Tue 71 72 NW 8 2672 3400 0 Blue 0
5 PM Tue 70 69 NW 8 2628 3400 0 Blue 0
6 PM Tue 68 66 NW 8 2628 3400 0 Blue 0
7 PM Tue 64 62 NW 8 2628 3400 0 Blue 0
8 PM Tue 61 59 NW 8 2628 3400 0 Blue 0
9 PM Tue 59 57 NW 8 2628 3400 0 Blue 0
10 PM Tue 57 55 NW 8 2628 3400 0 Blue 0
11 PM Tue 56 54 N 8 2628 3400 0 Blue 0
12 Midnight Wed 54 52 N 8 2628 3400 0 Blue 0
1 AM Wed 52 50 N 8 2628 3400 0 Blue 0
2 AM Wed 50 48 N 8 2628 3400 0 Blue 0
3 AM Wed 49 47 N 8 2628 3400 0 Blue 0
4 AM Wed 48 46 N 8 2628 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