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

Station:

KOAK

Date/Time:

17 NOV 2017

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 Fri 40 38 W 7 2592 3400 0 Blue 0
5 AM Fri 39 37 W 7 2592 3400 0 Blue 0
6 AM Fri 38 36 W 7 2592 3400 0 Blue 0
7 AM Fri 38 36 W 6 2592 3400 0 Blue 0
8 AM Fri 40 38 W 6 2592 3400 0 Blue 0
9 AM Fri 42 40 W 6 2592 3400 0 Blue 0
10 AM Fri 45 44 NE 5 3380 3400 0 Blue 2
11 AM Fri 48 48 NE 5 4717 3627 227 White 6
12 Noon Fri 49 49 NE 5 4939 3899 499 White 7
1 PM Fri 50 50 NE 5 5156 4572 1172 White 8
2 PM Fri 51 50 NE 5 5156 4572 1172 White 8
3 PM Fri 51 49 NE 5 4939 3899 499 White 7
4 PM Fri 49 47 N 3 4490 3400 0 White 5
5 PM Fri 47 45 N 3 3635 3400 0 Blue 3
6 PM Fri 44 42 N 3 2882 3400 0 Blue 0
7 PM Fri 41 39 NW 3 2592 3400 0 Blue 0
8 PM Fri 39 37 NW 3 2592 3400 0 Blue 0
9 PM Fri 39 37 NW 3 2592 3400 0 Blue 0
10 PM Fri 39 37 NW 7 2592 3400 0 Blue 0
11 PM Fri 39 37 NW 7 2592 3400 0 Blue 0
12 Midnight Sat 39 37 NW 7 2592 3400 0 Blue 0
1 AM Sat 39 37 NW 7 2592 3400 0 Blue 0
2 AM Sat 39 37 NW 7 2592 3400 0 Blue 0
3 AM Sat 39 37 NW 7 2592 3400 0 Blue 0
4 AM Sat 39 37 W 5 2592 3400 0 Blue 0
5 AM Sat 38 36 W 5 2592 3400 0 Blue 0
6 AM Sat 38 36 W 5 2592 3400 0 Blue 0
7 AM Sat 39 37 W 5 2592 3400 0 Blue 0
8 AM Sat 41 39 W 5 2592 3400 0 Blue 0
9 AM Sat 45 43 W 5 3132 3400 0 Blue 1
10 AM Sat 48 47 NE 2 4490 3400 0 White 5
11 AM Sat 51 51 NE 2 5372 4803 1403 White 9
12 Noon Sat 53 53 NE 2 5803 5803 2403 White 11
1 PM Sat 55 55 NE 2 6232 6232 2832 White 13
2 PM Sat 55 54 NE 2 6018 6018 2618 White 12
3 PM Sat 54 52 NE 2 5588 5588 2188 White 10
4 PM Sat 52 50 N 2 5156 4572 1172 White 8
5 PM Sat 49 47 N 2 4490 3400 0 White 5
6 PM Sat 46 44 N 2 3380 3400 0 Blue 2
7 PM Sat 43 41 N 2 2592 3400 0 Blue 0
8 PM Sat 42 40 N 2 2592 3400 0 Blue 0
9 PM Sat 41 39 N 2 2592 3400 0 Blue 0
10 PM Sat 41 39 NW 2 2592 3400 0 Blue 0
11 PM Sat 41 39 NW 2 2592 3400 0 Blue 0
12 Midnight Sun 40 38 NW 2 2592 3400 0 Blue 0
1 AM Sun 40 38 NW 2 2592 3400 0 Blue 0
2 AM Sun 39 37 NW 2 2592 3400 0 Blue 0
3 AM Sun 39 37 NW 2 2592 3400 0 Blue 0
4 AM Sun 39 37 W 2 2592 3400 0 Blue 0
5 AM Sun 38 36 W 2 2592 3400 0 Blue 0
6 AM Sun 38 36 W 2 2592 3400 0 Blue 0
7 AM Sun 39 37 W 2 2592 3400 0 Blue 0
8 AM Sun 41 39 W 2 2592 3400 0 Blue 0
9 AM Sun 44 42 W 2 2882 3400 0 Blue 0
10 AM Sun 47 46 S 3 3909 3400 0 Blue 4
11 AM Sun 51 50 S 3 5156 4572 1172 White 8
12 Noon Sun 54 53 S 3 5803 5803 2403 White 11
1 PM Sun 56 55 S 3 6232 6232 2832 White 13
2 PM Sun 56 55 S 3 6232 6232 2832 White 13
3 PM Sun 55 53 S 3 5803 5803 2403 White 11
4 PM Sun 52 50 S 5 5156 4572 1172 White 8
5 PM Sun 50 48 S 5 4717 3627 227 White 6
6 PM Sun 48 46 S 5 3909 3400 0 Blue 4
7 PM Sun 47 45 S 5 3635 3400 0 Blue 3
8 PM Sun 46 44 S 5 3380 3400 0 Blue 2
9 PM Sun 46 44 S 5 3380 3400 0 Blue 2
10 PM Sun 47 45 SW 6 3635 3400 0 Blue 3
11 PM Sun 47 45 SW 6 3635 3400 0 Blue 3
12 Midnight Mon 48 46 SW 6 3909 3400 0 Blue 4
1 AM Mon 48 46 SW 6 3909 3400 0 Blue 4
2 AM Mon 48 46 SW 6 3909 3400 0 Blue 4
3 AM Mon 48 46 SW 6 3909 3400 0 Blue 4
4 AM Mon 48 46 S 7 3909 3400 0 Blue 4
5 AM Mon 48 46 S 7 3909 3400 0 Blue 4
6 AM Mon 49 47 S 7 4490 3400 0 White 5
7 AM Mon 49 47 S 7 4490 3400 0 White 5
8 AM Mon 50 48 S 7 4717 3627 227 White 6
9 AM Mon 50 48 S 7 4717 3627 227 White 6
10 AM Mon 51 49 S 8 4939 3899 499 White 7
11 AM Mon 52 50 S 8 5156 4572 1172 White 8
12 Noon Mon 53 51 S 8 5372 4803 1403 White 9
1 PM Mon 55 53 S 8 5803 5803 2403 White 11
2 PM Mon 55 53 S 8 5803 5803 2403 White 11
3 PM Mon 55 53 S 8 5803 5803 2403 White 11
4 PM Mon 54 52 S 6 5588 5588 2188 White 10
5 PM Mon 53 51 S 6 5372 4803 1403 White 9
6 PM Mon 52 50 S 6 5156 4572 1172 White 8
7 PM Mon 51 49 S 6 4939 3899 499 White 7
8 PM Mon 51 49 S 6 4939 3899 499 White 7
9 PM Mon 51 49 S 6 4939 3899 499 White 7
10 PM Mon 51 49 S 5 4939 3899 499 White 7
11 PM Mon 51 49 S 5 4939 3899 499 White 7
12 Midnight Tue 51 49 S 5 4939 3899 499 White 7
1 AM Tue 51 49 S 5 4939 3899 499 White 7
2 AM Tue 52 50 S 5 5156 4572 1172 White 8
3 AM Tue 52 50 S 5 5156 4572 1172 White 8
4 AM Tue 53 51 E 7 5372 4803 1403 White 9
5 AM Tue 53 51 E 7 5372 4803 1403 White 9
6 AM Tue 53 51 E 7 5372 4803 1403 White 9
7 AM Tue 53 51 E 7 5372 4803 1403 White 9
8 AM Tue 53 51 E 7 5372 4803 1403 White 9
9 AM Tue 54 52 E 7 5588 5588 2188 White 10
10 AM Tue 54 52 S 9 5588 5588 2188 White 10
11 AM Tue 55 53 S 9 5803 5803 2403 White 11
12 Noon Tue 55 53 S 9 5803 5803 2403 White 11
1 PM Tue 56 54 S 9 6018 6018 2618 White 12
2 PM Tue 56 54 S 9 6018 6018 2618 White 12
3 PM Tue 56 54 S 9 6018 6018 2618 White 12
4 PM Tue 56 54 S 10 6018 6018 2618 White 12
5 PM Tue 56 54 S 10 6018 6018 2618 White 12
6 PM Tue 55 53 S 10 5803 5803 2403 White 11
7 PM Tue 55 53 S 10 5803 5803 2403 White 11
8 PM Tue 54 52 S 10 5588 5588 2188 White 10
9 PM Tue 54 52 S 10 5588 5588 2188 White 10
10 PM Tue 53 51 S 12 5372 4803 1403 White 9
11 PM Tue 53 51 S 12 5372 4803 1403 White 9
12 Midnight Wed 53 51 S 12 5372 4803 1403 White 9
1 AM Wed 53 51 S 12 5372 4803 1403 White 9
2 AM Wed 54 52 S 12 5588 5588 2188 White 10
3 AM Wed 54 52 S 12 5588 5588 2188 White 10
4 AM Wed 53 51 S 13 5372 4803 1403 White 9
5 AM Wed 53 51 S 13 5372 4803 1403 White 9
6 AM Wed 53 51 S 13 5372 4803 1403 White 9
7 AM Wed 53 51 S 13 5372 4803 1403 White 9
8 AM Wed 54 52 S 13 5588 5588 2188 White 10
9 AM Wed 55 53 S 13 5803 5803 2403 White 11
10 AM Wed 56 54 S 10 6018 6018 2618 White 12
11 AM Wed 57 55 S 10 6232 6232 2832 White 13
12 Noon Wed 58 56 S 10 6445 6445 3045 White 14
1 PM Wed 58 56 S 10 6445 6445 3045 White 14
2 PM Wed 58 56 S 10 6445 6445 3045 White 14
3 PM Wed 58 56 S 10 6445 6445 3045 White 14
4 PM Wed 57 55 S 9 6232 6232 2832 White 13
5 PM Wed 56 54 S 9 6018 6018 2618 White 12
6 PM Wed 55 53 S 9 5803 5803 2403 White 11
7 PM Wed 55 53 S 9 5803 5803 2403 White 11
8 PM Wed 54 52 S 9 5588 5588 2188 White 10
9 PM Wed 54 52 S 9 5588 5588 2188 White 10
10 PM Wed 54 52 SW 9 5588 5588 2188 White 10
11 PM Wed 53 51 SW 9 5372 4803 1403 White 9
12 Midnight Thu 53 51 SW 9 5372 4803 1403 White 9
1 AM Thu 53 51 SW 9 5372 4803 1403 White 9
2 AM Thu 53 51 SW 9 5372 4803 1403 White 9
3 AM Thu 53 51 SW 9 5372 4803 1403 White 9

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