Detailed Predictions for: Dumps
Launch Lat, Long, Altitude (f): 37.67264, -122.49, 200
LZ Altitude (f): 0
Sounding

Station:

 KOAK

Date/Time:

 26 APR 2024

Temp/Wind data from:

NOAA Digital Forecast

Site Forecasts
Time
(Local)		 High
Temp
Puddle
Temp
Wind
 (mph)		 Wind
 Gust		 Thermal
Ceiling
(ft)		 Soaring
Ceiling
(ft)		 Above
Launch
(ft)		 Thermal
Type		 Thermal
Index
(F)
12 Midnight Fri 54 34 W 12 17 476 476 276 Blue 0
1 AM Fri 54 34 W 11 16 476 476 276 Blue 0
2 AM Fri 54 34 W 12 16 476 476 276 Blue 0
3 AM Fri 54 34 WNW 13 18 476 476 276 Blue 0
4 AM Fri 53 33 WNW 13 18 476 476 276 Blue 0
5 AM Fri 53 33 WNW 13 18 476 476 276 Blue 0
6 AM Fri 53 33 NNW 16 20 476 476 276 Blue 0
7 AM Fri 53 33 WNW 14 21 476 476 276 Blue 0
8 AM Fri 54 34 WNW 13 19 476 476 276 Blue 0
9 AM Fri 54 34 WNW 14 19 476 476 276 Blue 0
10 AM Fri 55 35 WNW 15 20 476 476 276 Blue 0
11 AM Fri 56 37 WNW 17 22 476 476 276 Blue 0
12 Noon Fri 57 38 WNW 18 22 476 476 276 Blue 0
1 PM Fri 57 44 WNW 19 23 476 476 276 Blue 0
2 PM Fri 57 44 WNW 21 24 476 476 276 Blue 0
3 PM Fri 57 42 WNW 23 27 476 476 276 Blue 0
4 PM Fri 57 41 WNW 23 28 476 476 276 Blue 0
5 PM Fri 56 38 WNW 24 29 476 476 276 Blue 0
6 PM Fri 55 36 WNW 23 28 476 476 276 Blue 0
7 PM Fri 54 34 WNW 23 28 476 476 276 Blue 0
8 PM Fri 53 33 WNW 22 29 476 476 276 Blue 0
9 PM Fri 53 33 WNW 20 27 476 476 276 Blue 0
10 PM Fri 52 32 NW 18 25 476 476 276 Blue 0
11 PM Fri 52 32 NW 15 21 476 476 276 Blue 0
12 Midnight Sat 51 31 NW 13 19 476 476 276 Blue 0
1 AM Sat 51 31 NW 11 16 476 476 276 Blue 0
2 AM Sat 51 31 NW 9 13 476 476 276 Blue 0
3 AM Sat 50 30 NW 9 13 476 476 276 Blue 0
4 AM Sat 50 30 NW 7 10 476 476 276 Blue 0
5 AM Sat 49 29 NW 6 9 476 476 276 Blue 0
6 AM Sat 49 29 NNW 4 7 476 476 276 Blue 0
7 AM Sat 50 30 NW 4 7 476 476 276 Blue 0
8 AM Sat 51 32 NW 4 6 476 476 276 Blue 0
9 AM Sat 52 34 NW 4 5 476 476 276 Blue 0
10 AM Sat 54 38 WNW 5 6 476 476 276 Blue 0
11 AM Sat 55 40 WNW 8 9 476 476 276 Blue 0
12 Noon Sat 56 42 WNW 10 12 476 476 276 Blue 0
1 PM Sat 57 44 WNW 13 15 476 476 276 Blue 0
2 PM Sat 57 44 WNW 17 21 476 476 276 Blue 0
3 PM Sat 57 43 WNW 19 23 476 476 276 Blue 0
4 PM Sat 57 41 WNW 21 25 476 476 276 Blue 0
5 PM Sat 56 38 WNW 20 24 476 476 276 Blue 0
6 PM Sat 56 36 WNW 20 24 476 476 276 Blue 0
7 PM Sat 55 35 WNW 19 24 476 476 276 Blue 0
8 PM Sat 54 34 WNW 17 23 476 476 276 Blue 0
9 PM Sat 54 34 WNW 15 22 476 476 276 Blue 0
10 PM Sat 53 33 WNW 15 22 476 476 276 Blue 0
11 PM Sat 53 33 WNW 15 23 476 476 276 Blue 0
12 Midnight Sun 53 33 WNW 16 24 476 476 276 Blue 0
1 AM Sun 52 32 WNW 16 23 476 476 276 Blue 0
2 AM Sun 52 32 WNW 16 23 476 476 276 Blue 0
3 AM Sun 52 32 NW 13 19 476 476 276 Blue 0
4 AM Sun 52 32 NW 10 15 476 476 276 Blue 0
5 AM Sun 51 31 NW 9 14 476 476 276 Blue 0
6 AM Sun 51 31 NW 8 13 476 476 276 Blue 0
7 AM Sun 52 32 NW 6 9 476 476 276 Blue 0
8 AM Sun 53 33 NW 5 7 476 476 276 Blue 0
9 AM Sun 54 36 NW 6 8 476 476 276 Blue 0
10 AM Sun 55 39 WNW 8 10 476 476 276 Blue 0
11 AM Sun 57 43 WNW 12 14 476 476 276 Blue 0
12 Noon Sun 57 44 WNW 14 17 476 476 276 Blue 0
1 PM Sun 58 46 WNW 18 22 476 476 276 Blue 0
2 PM Sun 58 45 WNW 19 24 476 476 276 Blue 0
3 PM Sun 57 43 WNW 21 25 476 476 276 Blue 0
4 PM Sun 57 41 WNW 20 26 476 476 276 Blue 0
5 PM Sun 56 38 WNW 21 26 476 476 276 Blue 0
6 PM Sun 55 36 WNW 22 27 476 476 276 Blue 0
7 PM Sun 54 34 WNW 23 28 476 476 276 Blue 0
8 PM Sun 52 32 WNW 21 29 476 476 276 Blue 0
9 PM Sun 52 32 WNW 22 30 476 476 276 Blue 0
10 PM Sun 51 31 WNW 21 29 476 476 276 Blue 0
11 PM Sun 51 31 WNW 20 28 476 476 276 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 or WeatherAPI.com website.  Puddle temperatures can exceed this temperature. 

Puddle Temp: This estimate is based on the High Temp and the National Weather Service or WeatherAPI.com 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 or WeatherAPI.com website.

Wind Gust: This estimate is taken from the National Weather Service or WeatherAPI.com 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 [email protected]