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

Station:

KOAK

Date/Time:

11 DEC 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)
4 AM Tue 40 38 N 6 2739 3400 0 Blue 0
5 AM Tue 40 38 N 6 2739 3400 0 Blue 0
6 AM Tue 40 38 N 6 2739 3400 0 Blue 0
7 AM Tue 41 39 N 6 2739 3400 0 Blue 0
8 AM Tue 43 41 N 6 2739 3400 0 Blue 0
9 AM Tue 46 44 N 6 2739 3400 0 Blue 0
10 AM Tue 50 48 N 3 3040 3400 0 Blue 0
11 AM Tue 52 50 N 3 4052 3400 0 Blue 0
12 Noon Tue 54 52 N 3 5191 3539 139 Blue 1
1 PM Tue 55 53 NW 3 5253 4031 631 Blue 2
2 PM Tue 56 54 NW 3 5316 4578 1178 Blue 3
3 PM Tue 56 54 NW 3 5316 4578 1178 Blue 3
4 PM Tue 55 53 W 7 5253 4031 631 Blue 2
5 PM Tue 53 51 W 7 4622 3400 0 Blue 0
6 PM Tue 50 48 W 7 3040 3400 0 Blue 0
7 PM Tue 48 46 W 6 2739 3400 0 Blue 0
8 PM Tue 47 45 W 6 2739 3400 0 Blue 0
9 PM Tue 47 45 W 6 2739 3400 0 Blue 0
10 PM Tue 47 45 W 6 2739 3400 0 Blue 0
11 PM Tue 46 44 W 6 2739 3400 0 Blue 0
12 Midnight Wed 45 43 W 6 2739 3400 0 Blue 0
1 AM Wed 45 43 W 6 2739 3400 0 Blue 0
2 AM Wed 44 42 W 6 2739 3400 0 Blue 0
3 AM Wed 44 42 W 6 2739 3400 0 Blue 0
4 AM Wed 43 41 NW 5 2739 3400 0 Blue 0
5 AM Wed 42 40 NW 5 2739 3400 0 Blue 0
6 AM Wed 41 39 NW 5 2739 3400 0 Blue 0
7 AM Wed 41 39 N 8 2739 3400 0 Blue 0
8 AM Wed 43 41 N 8 2739 3400 0 Blue 0
9 AM Wed 45 43 N 8 2739 3400 0 Blue 0
10 AM Wed 48 47 N 8 2739 3400 0 Blue 0
11 AM Wed 50 49 N 8 3553 3400 0 Blue 0
12 Noon Wed 53 52 N 8 5191 3539 139 Blue 1
1 PM Wed 54 53 N 9 5253 4031 631 Blue 2
2 PM Wed 54 53 N 9 5253 4031 631 Blue 2
3 PM Wed 53 51 N 9 4622 3400 0 Blue 0
4 PM Wed 52 50 N 5 4052 3400 0 Blue 0
5 PM Wed 50 48 N 5 3040 3400 0 Blue 0
6 PM Wed 47 45 N 5 2739 3400 0 Blue 0
7 PM Wed 46 44 N 5 2739 3400 0 Blue 0
8 PM Wed 45 43 N 5 2739 3400 0 Blue 0
9 PM Wed 45 43 N 5 2739 3400 0 Blue 0
10 PM Wed 45 43 NW 5 2739 3400 0 Blue 0
11 PM Wed 45 43 NW 5 2739 3400 0 Blue 0
12 Midnight Thu 44 42 NW 5 2739 3400 0 Blue 0
1 AM Thu 44 42 NW 5 2739 3400 0 Blue 0
2 AM Thu 43 41 NW 5 2739 3400 0 Blue 0
3 AM Thu 43 41 NW 5 2739 3400 0 Blue 0
4 AM Thu 42 40 NW 2 2739 3400 0 Blue 0
5 AM Thu 41 39 NW 2 2739 3400 0 Blue 0
6 AM Thu 41 39 NW 2 2739 3400 0 Blue 0
7 AM Thu 41 39 NW 2 2739 3400 0 Blue 0
8 AM Thu 43 41 NW 2 2739 3400 0 Blue 0
9 AM Thu 46 44 NW 2 2739 3400 0 Blue 0
10 AM Thu 49 47 SE 3 2739 3400 0 Blue 0
11 AM Thu 51 50 SE 3 4052 3400 0 Blue 0
12 Noon Thu 53 52 SE 3 5191 3539 139 Blue 1
1 PM Thu 54 53 SE 3 5253 4031 631 Blue 2
2 PM Thu 55 54 SE 3 5316 4578 1178 Blue 3
3 PM Thu 55 53 SE 3 5253 4031 631 Blue 2
4 PM Thu 53 51 S 3 4622 3400 0 Blue 0
5 PM Thu 50 48 S 3 3040 3400 0 Blue 0
6 PM Thu 46 44 S 3 2739 3400 0 Blue 0
7 PM Thu 44 42 S 3 2739 3400 0 Blue 0
8 PM Thu 42 40 S 3 2739 3400 0 Blue 0
9 PM Thu 42 40 S 3 2739 3400 0 Blue 0
10 PM Thu 42 40 S 7 2739 3400 0 Blue 0
11 PM Thu 42 40 S 7 2739 3400 0 Blue 0
12 Midnight Fri 41 39 S 7 2739 3400 0 Blue 0
1 AM Fri 41 39 S 7 2739 3400 0 Blue 0
2 AM Fri 41 39 S 7 2739 3400 0 Blue 0
3 AM Fri 41 39 S 7 2739 3400 0 Blue 0
4 AM Fri 41 39 S 8 2739 3400 0 Blue 0
5 AM Fri 41 39 S 8 2739 3400 0 Blue 0
6 AM Fri 41 39 S 8 2739 3400 0 Blue 0
7 AM Fri 41 39 S 8 2739 3400 0 Blue 0
8 AM Fri 42 40 S 8 2739 3400 0 Blue 0
9 AM Fri 44 42 S 8 2739 3400 0 Blue 0
10 AM Fri 45 43 S 13 2739 3400 0 Blue 0
11 AM Fri 47 45 S 13 2739 3400 0 Blue 0
12 Noon Fri 47 45 S 13 2739 3400 0 Blue 0
1 PM Fri 48 46 S 13 2739 3400 0 Blue 0
2 PM Fri 48 46 S 13 2739 3400 0 Blue 0
3 PM Fri 48 46 S 13 2739 3400 0 Blue 0
4 PM Fri 47 45 SW 8 2739 3400 0 Blue 0
5 PM Fri 46 44 SW 8 2739 3400 0 Blue 0
6 PM Fri 45 43 SW 8 2739 3400 0 Blue 0
7 PM Fri 44 42 SW 8 2739 3400 0 Blue 0
8 PM Fri 42 40 SW 8 2739 3400 0 Blue 0
9 PM Fri 41 39 SW 8 2739 3400 0 Blue 0
10 PM Fri 40 38 NE 3 2739 3400 0 Blue 0
11 PM Fri 40 38 NE 3 2739 3400 0 Blue 0
12 Midnight Sat 40 38 NE 3 2739 3400 0 Blue 0
1 AM Sat 40 38 NE 3 2739 3400 0 Blue 0
2 AM Sat 40 38 NE 3 2739 3400 0 Blue 0
3 AM Sat 40 38 NE 3 2739 3400 0 Blue 0
4 AM Sat 39 37 S 5 2739 3400 0 Blue 0
5 AM Sat 39 37 S 5 2739 3400 0 Blue 0
6 AM Sat 39 37 S 5 2739 3400 0 Blue 0
7 AM Sat 40 38 S 5 2739 3400 0 Blue 0
8 AM Sat 42 40 S 5 2739 3400 0 Blue 0
9 AM Sat 44 42 S 5 2739 3400 0 Blue 0
10 AM Sat 46 44 SE 6 2739 3400 0 Blue 0
11 AM Sat 47 45 SE 6 2739 3400 0 Blue 0
12 Noon Sat 49 47 SE 6 2739 3400 0 Blue 0
1 PM Sat 50 48 SE 6 3040 3400 0 Blue 0
2 PM Sat 50 48 SE 6 3040 3400 0 Blue 0
3 PM Sat 50 48 SE 6 3040 3400 0 Blue 0
4 PM Sat 49 47 S 7 2739 3400 0 Blue 0
5 PM Sat 47 45 S 7 2739 3400 0 Blue 0
6 PM Sat 45 43 S 7 2739 3400 0 Blue 0
7 PM Sat 44 42 S 7 2739 3400 0 Blue 0
8 PM Sat 43 41 S 7 2739 3400 0 Blue 0
9 PM Sat 43 41 S 7 2739 3400 0 Blue 0
10 PM Sat 43 41 S 12 2739 3400 0 Blue 0
11 PM Sat 44 42 S 12 2739 3400 0 Blue 0
12 Midnight Sun 44 42 S 12 2739 3400 0 Blue 0
1 AM Sun 44 42 S 12 2739 3400 0 Blue 0
2 AM Sun 44 42 S 12 2739 3400 0 Blue 0
3 AM Sun 44 42 S 12 2739 3400 0 Blue 0
4 AM Sun 44 42 S 15 2739 3400 0 Blue 0
5 AM Sun 44 42 S 15 2739 3400 0 Blue 0
6 AM Sun 44 42 S 15 2739 3400 0 Blue 0
7 AM Sun 44 42 S 15 2739 3400 0 Blue 0
8 AM Sun 44 42 S 15 2739 3400 0 Blue 0
9 AM Sun 45 43 S 15 2739 3400 0 Blue 0
10 AM Sun 45 43 S 18 2739 3400 0 Blue 0
11 AM Sun 46 44 S 18 2739 3400 0 Blue 0
12 Noon Sun 47 45 S 18 2739 3400 0 Blue 0
1 PM Sun 48 46 S 18 2739 3400 0 Blue 0
2 PM Sun 48 46 S 18 2739 3400 0 Blue 0
3 PM Sun 48 46 S 18 2739 3400 0 Blue 0
4 PM Sun 47 45 SW 10 2739 3400 0 Blue 0
5 PM Sun 46 44 SW 10 2739 3400 0 Blue 0
6 PM Sun 45 43 SW 10 2739 3400 0 Blue 0
7 PM Sun 45 43 SW 10 2739 3400 0 Blue 0
8 PM Sun 44 42 SW 10 2739 3400 0 Blue 0
9 PM Sun 43 41 SW 10 2739 3400 0 Blue 0
10 PM Sun 43 41 W 8 2739 3400 0 Blue 0
11 PM Sun 43 41 W 8 2739 3400 0 Blue 0
12 Midnight Mon 42 40 W 8 2739 3400 0 Blue 0
1 AM Mon 42 40 W 8 2739 3400 0 Blue 0
2 AM Mon 42 40 W 8 2739 3400 0 Blue 0
3 AM Mon 42 40 W 8 2739 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