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

Station:

 KOAK

Date/Time:

 15 MAR 2010

Temp/Wind data from:

NOAA Digital Forecast

Time
(Local)		 High
Temp
Puddle
Temp
Wind
 (mph)		 Thermal
Ceiling
(ft)		 Soaring
Ceiling
(ft)		 Above
Launch
(ft)		 Thermal
Type		 Thermal
Index
(F)
5 AM Mon 40 40 N 2 2739 3400 0 Blue 0
6 AM Mon 40 40 N 2 2739 3400 0 Blue 0
7 AM Mon 40 40 N 2 2739 3400 0 Blue 0
8 AM Mon 42 42 NE 2 2739 3400 0 Blue 0
9 AM Mon 46 47 NE 2 2739 3400 0 Blue 0
10 AM Mon 52 54 NE 2 3215 3400 0 Blue 0
11 AM Mon 58 61 E 4 4366 3868 468 Blue 7
12 Noon Mon 62 66 E 4 5455 4684 1284 Blue 12
1 PM Mon 65 70 E 4 6999 5953 2553 Blue 16
2 PM Mon 68 73 SE 4 7681 6970 3570 Blue 19
3 PM Mon 68 72 SE 4 7427 6701 3301 Blue 18
4 PM Mon 67 69 SE 4 6749 5413 2013 Blue 15
5 PM Mon 65 66 S 5 5455 4684 1284 Blue 12
6 PM Mon 63 63 S 5 4694 4195 795 Blue 9
7 PM Mon 59 59 S 5 4038 3540 140 Blue 5
8 PM Mon 54 54 S 3 3215 3400 0 Blue 0
9 PM Mon 51 51 S 3 2739 3400 0 Blue 0
10 PM Mon 48 48 S 3 2739 3400 0 Blue 0
11 PM Mon 48 48 S 2 2739 3400 0 Blue 0
12 Midnight Tue 48 48 S 2 2739 3400 0 Blue 0
1 AM Tue 47 47 S 2 2739 3400 0 Blue 0
2 AM Tue 46 46 S 2 2739 3400 0 Blue 0
3 AM Tue 45 45 S 2 2739 3400 0 Blue 0
4 AM Tue 44 44 S 2 2739 3400 0 Blue 0
5 AM Tue 43 43 S 1 2739 3400 0 Blue 0
6 AM Tue 43 43 S 1 2739 3400 0 Blue 0
7 AM Tue 43 43 S 1 2739 3400 0 Blue 0
8 AM Tue 44 44 S 3 2739 3400 0 Blue 0
9 AM Tue 48 48 S 3 2739 3400 0 Blue 0
10 AM Tue 52 53 S 3 2817 3400 0 Blue 0
11 AM Tue 56 58 S 5 3874 3400 0 Blue 4
12 Noon Tue 60 63 S 5 4694 4195 795 Blue 9
1 PM Tue 61 64 S 5 4857 4358 958 Blue 10
2 PM Tue 64 67 SW 8 5993 4846 1446 Blue 13
3 PM Tue 64 66 SW 8 5455 4684 1284 Blue 12
4 PM Tue 63 64 SW 8 4857 4358 958 Blue 10
5 PM Tue 62 62 W 6 4530 4031 631 Blue 8
6 PM Tue 60 60 W 6 4202 3704 304 Blue 6
7 PM Tue 56 56 W 6 3544 3400 0 Blue 2
8 PM Tue 52 52 W 6 2739 3400 0 Blue 0
9 PM Tue 49 49 W 6 2739 3400 0 Blue 0
10 PM Tue 47 47 W 6 2739 3400 0 Blue 0
11 PM Tue 47 47 NW 4 2739 3400 0 Blue 0
12 Midnight Wed 46 46 NW 4 2739 3400 0 Blue 0
1 AM Wed 46 46 NW 4 2739 3400 0 Blue 0
2 AM Wed 44 44 NW 4 2739 3400 0 Blue 0
3 AM Wed 44 44 NW 4 2739 3400 0 Blue 0
4 AM Wed 43 43 NW 4 2739 3400 0 Blue 0
5 AM Wed 42 42 N 3 2739 3400 0 Blue 0
6 AM Wed 42 42 N 3 2739 3400 0 Blue 0
7 AM Wed 42 42 N 3 2739 3400 0 Blue 0
8 AM Wed 44 44 N 3 2739 3400 0 Blue 0
9 AM Wed 49 49 N 3 2739 3400 0 Blue 0
10 AM Wed 55 57 N 3 3709 3400 0 Blue 3
11 AM Wed 61 64 N 3 4857 4358 958 Blue 10
12 Noon Wed 66 70 N 3 6999 5953 2553 Blue 16
1 PM Wed 68 72 N 3 7427 6701 3301 Blue 18
2 PM Wed 72 76 N 3 8805 7619 4219 Blue 22
3 PM Wed 72 75 N 3 8435 7394 3994 Blue 21
4 PM Wed 70 72 N 3 7427 6701 3301 Blue 18
5 PM Wed 69 70 W 4 6999 5953 2553 Blue 16
6 PM Wed 66 66 W 4 5455 4684 1284 Blue 12
7 PM Wed 61 61 W 4 4366 3868 468 Blue 7
8 PM Wed 55 55 W 4 3380 3400 0 Blue 1
9 PM Wed 52 52 W 4 2739 3400 0 Blue 0
10 PM Wed 48 48 W 4 2739 3400 0 Blue 0
11 PM Wed 48 48 N 3 2739 3400 0 Blue 0
12 Midnight Thu 48 48 N 3 2739 3400 0 Blue 0
1 AM Thu 47 47 N 3 2739 3400 0 Blue 0
2 AM Thu 45 45 N 3 2739 3400 0 Blue 0
3 AM Thu 44 44 N 3 2739 3400 0 Blue 0
4 AM Thu 43 43 N 3 2739 3400 0 Blue 0
5 AM Thu 42 42 N 3 2739 3400 0 Blue 0
6 AM Thu 42 42 N 3 2739 3400 0 Blue 0
7 AM Thu 42 42 N 3 2739 3400 0 Blue 0
8 AM Thu 44 44 N 3 2739 3400 0 Blue 0
9 AM Thu 49 50 N 3 2739 3400 0 Blue 0
10 AM Thu 56 58 N 3 3874 3400 0 Blue 4
11 AM Thu 63 66 NE 3 5455 4684 1284 Blue 12
12 Noon Thu 67 71 NE 3 7214 6329 2929 Blue 17
1 PM Thu 70 75 NE 3 8435 7394 3994 Blue 21
2 PM Thu 74 79 NE 3 9886 8732 5332 Blue 25
3 PM Thu 74 78 NE 3 9530 8366 4966 Blue 24
4 PM Thu 72 74 NE 3 8061 7182 3782 Blue 20
5 PM Thu 71 72 N 6 7427 6701 3301 Blue 18
6 PM Thu 68 68 N 6 6373 5009 1609 Blue 14
7 PM Thu 62 62 N 6 4530 4031 631 Blue 8
8 PM Thu 56 56 N 6 3544 3400 0 Blue 2
9 PM Thu 52 52 N 6 2739 3400 0 Blue 0
10 PM Thu 48 48 N 6 2739 3400 0 Blue 0
11 PM Thu 48 48 N 6 2739 3400 0 Blue 0
12 Midnight Fri 48 48 N 6 2739 3400 0 Blue 0
1 AM Fri 47 47 N 6 2739 3400 0 Blue 0
2 AM Fri 44 44 N 6 2739 3400 0 Blue 0
3 AM Fri 43 43 N 6 2739 3400 0 Blue 0
4 AM Fri 42 42 N 6 2739 3400 0 Blue 0
5 AM Fri 41 41 N 6 2739 3400 0 Blue 0
6 AM Fri 41 41 N 6 2739 3400 0 Blue 0
7 AM Fri 41 41 N 6 2739 3400 0 Blue 0
8 AM Fri 43 43 N 6 2739 3400 0 Blue 0
9 AM Fri 48 49 N 6 2739 3400 0 Blue 0
10 AM Fri 54 56 N 6 3544 3400 0 Blue 2
11 AM Fri 61 64 N 5 4857 4358 958 Blue 10
12 Noon Fri 65 69 N 5 6749 5413 2013 Blue 15
1 PM Fri 68 73 N 5 7681 6970 3570 Blue 19
2 PM Fri 72 77 N 5 9170 7995 4595 Blue 23
3 PM Fri 72 76 N 5 8805 7619 4219 Blue 22
4 PM Fri 70 72 N 5 7427 6701 3301 Blue 18
5 PM Fri 69 70 SW 2 6999 5953 2553 Blue 16
6 PM Fri 66 66 SW 2 5455 4684 1284 Blue 12
7 PM Fri 61 61 SW 2 4366 3868 468 Blue 7
8 PM Fri 54 54 SW 2 3215 3400 0 Blue 0
9 PM Fri 51 51 SW 2 2739 3400 0 Blue 0
10 PM Fri 47 47 SW 2 2739 3400 0 Blue 0
11 PM Fri 47 47 NW 4 2739 3400 0 Blue 0
12 Midnight Sat 46 46 NW 4 2739 3400 0 Blue 0
1 AM Sat 46 46 NW 4 2739 3400 0 Blue 0
2 AM Sat 43 43 NW 4 2739 3400 0 Blue 0
3 AM Sat 42 42 NW 4 2739 3400 0 Blue 0
4 AM Sat 41 41 NW 4 2739 3400 0 Blue 0
5 AM Sat 40 40 NW 3 2739 3400 0 Blue 0
6 AM Sat 40 40 NW 3 2739 3400 0 Blue 0
7 AM Sat 40 40 NW 3 2739 3400 0 Blue 0
8 AM Sat 42 42 NW 3 2739 3400 0 Blue 0
9 AM Sat 46 46 NW 3 2739 3400 0 Blue 0
10 AM Sat 52 54 NW 3 3215 3400 0 Blue 0
11 AM Sat 58 61 S 3 4366 3868 468 Blue 7
12 Noon Sat 62 66 S 3 5455 4684 1284 Blue 12
1 PM Sat 65 69 S 3 6749 5413 2013 Blue 15
2 PM Sat 68 72 S 3 7427 6701 3301 Blue 18
3 PM Sat 68 71 S 3 7214 6329 2929 Blue 17
4 PM Sat 67 69 S 3 6749 5413 2013 Blue 15
5 PM Sat 65 66 SW 5 5455 4684 1284 Blue 12
6 PM Sat 63 63 SW 5 4694 4195 795 Blue 9
7 PM Sat 58 58 SW 5 3874 3400 0 Blue 4
8 PM Sat 53 53 SW 5 2817 3400 0 Blue 0
9 PM Sat 50 50 SW 5 2739 3400 0 Blue 0
10 PM Sat 47 47 SW 5 2739 3400 0 Blue 0
11 PM Sat 47 47 W 4 2739 3400 0 Blue 0
12 Midnight Sun 46 46 W 4 2739 3400 0 Blue 0
1 AM Sun 46 46 W 4 2739 3400 0 Blue 0
2 AM Sun 44 44 W 4 2739 3400 0 Blue 0
3 AM Sun 43 43 W 4 2739 3400 0 Blue 0
4 AM Sun 42 42 W 4 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