Detailed Predictions for: Timberline
Launch Lat, Long, Altitude (f): 39.509442, -122.937570, 5810
LZ Altitude (f): 1840
Sounding

Station:

KOAK

Date/Time:

21 SEP 2021

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 Tue 58 58 ENE 4 8 5151 5810 0 Blue 0
1 AM Tue 57 57 ENE 4 8 5151 5810 0 Blue 0
2 AM Tue 57 57 ENE 4 8 5151 5810 0 Blue 0
3 AM Tue 57 57 ENE 4 8 5151 5810 0 Blue 0
4 AM Tue 56 56 ENE 4 8 5151 5810 0 Blue 0
5 AM Tue 56 56 ENE 3 8 5151 5810 0 Blue 0
6 AM Tue 56 56 ENE 4 8 5151 5810 0 Blue 0
7 AM Tue 56 56 ENE 4 9 5151 5810 0 Blue 0
8 AM Tue 60 60 ENE 3 8 5151 5810 0 Blue 0
9 AM Tue 76 77 E 2 2 8454 7723 1913 Blue 6
10 AM Tue 83 85 SSE 2 2 11792 10303 4493 Blue 14
11 AM Tue 88 92 SSW 3 3 16778 15534 9724 Blue 21
12 Noon Tue 90 95 SSW 4 5 19467 16673 10863 Blue 24
1 PM Tue 91 96 SSW 5 5 19898 16962 11152 Blue 25
2 PM Tue 92 97 SSW 6 6 20600 18024 12214 Blue 26
3 PM Tue 92 96 SW 8 9 19898 16962 11152 Blue 25
4 PM Tue 90 93 WSW 8 10 17069 15936 10126 Blue 22
5 PM Tue 85 86 WSW 6 6 13036 10598 4788 Blue 15
6 PM Tue 80 80 WSW 3 4 9681 8407 2597 Blue 9
7 PM Tue 66 66 W 2 5 5151 5810 0 Blue 0
8 PM Tue 61 61 NNE 1 2 5151 5810 0 Blue 0
9 PM Tue 60 60 NE 2 6 5151 5810 0 Blue 0
10 PM Tue 60 60 ENE 3 6 5151 5810 0 Blue 0
11 PM Tue 59 59 ENE 3 6 5151 5810 0 Blue 0
12 Midnight Wed 59 59 NE 3 6 5151 5810 0 Blue 0
1 AM Wed 59 59 ENE 3 6 5151 5810 0 Blue 0
2 AM Wed 58 58 ENE 3 6 5151 5810 0 Blue 0
3 AM Wed 58 58 NE 2 5 5151 5810 0 Blue 0
4 AM Wed 57 57 NE 2 6 5151 5810 0 Blue 0
5 AM Wed 57 57 NE 3 6 5151 5810 0 Blue 0
6 AM Wed 57 57 ENE 2 6 5151 5810 0 Blue 0
7 AM Wed 57 57 NE 2 6 5151 5810 0 Blue 0
8 AM Wed 60 60 NE 2 4 5151 5810 0 Blue 0
9 AM Wed 73 74 NW 2 2 7739 7040 1230 Blue 4
10 AM Wed 79 81 W 2 2 10017 8960 3150 Blue 10
11 AM Wed 84 88 W 3 3 15016 11534 5724 Blue 17
12 Noon Wed 86 91 WSW 4 5 16467 14755 8945 Blue 20
1 PM Wed 88 93 W 5 6 17069 15936 10126 Blue 22
2 PM Wed 88 93 W 7 8 17069 15936 10126 Blue 22
3 PM Wed 87 91 W 8 10 16467 14755 8945 Blue 20
4 PM Wed 85 88 W 7 8 15016 11534 5724 Blue 17
5 PM Wed 83 84 W 6 6 10908 9973 4163 Blue 13
6 PM Wed 79 79 WSW 4 4 9341 8036 2226 Blue 8
7 PM Wed 64 64 W 2 6 5151 5810 0 Blue 0
8 PM Wed 59 59 N 1 2 5151 5810 0 Blue 0
9 PM Wed 58 58 NNE 3 8 5151 5810 0 Blue 0
10 PM Wed 57 57 NNE 4 8 5151 5810 0 Blue 0
11 PM Wed 56 56 NNE 4 10 5151 5810 0 Blue 0
12 Midnight Thu 55 55 NNE 4 8 5151 5810 0 Blue 0
1 AM Thu 55 55 NNE 4 9 5151 5810 0 Blue 0
2 AM Thu 56 56 NE 4 9 5151 5810 0 Blue 0
3 AM Thu 55 55 NE 4 9 5151 5810 0 Blue 0
4 AM Thu 55 55 NE 4 9 5151 5810 0 Blue 0
5 AM Thu 56 56 NE 4 9 5151 5810 0 Blue 0
6 AM Thu 55 55 NE 4 9 5151 5810 0 Blue 0
7 AM Thu 55 55 NE 4 9 5151 5810 0 Blue 0
8 AM Thu 59 59 NE 4 8 5151 5810 0 Blue 0
9 AM Thu 74 75 NE 2 2 7937 7251 1441 Blue 4
10 AM Thu 81 83 N 2 2 10638 9640 3830 Blue 12
11 AM Thu 88 92 NW 2 2 16778 15534 9724 Blue 21
12 Noon Thu 91 96 W 3 3 19898 16962 11152 Blue 25
1 PM Thu 92 97 W 4 5 20600 18024 12214 Blue 26
2 PM Thu 93 98 W 6 7 21611 19289 13479 Blue 27
3 PM Thu 92 96 W 7 8 19898 16962 11152 Blue 25
4 PM Thu 90 93 WSW 6 7 17069 15936 10126 Blue 22
5 PM Thu 87 88 WSW 5 6 15016 11534 5724 Blue 17
6 PM Thu 80 80 WSW 3 4 9681 8407 2597 Blue 9
7 PM Thu 67 67 W 1 2 5151 5810 0 Blue 0
8 PM Thu 63 63 NE 1 3 5151 5810 0 Blue 0
9 PM Thu 62 62 NE 3 6 5151 5810 0 Blue 0
10 PM Thu 61 61 NE 3 7 5151 5810 0 Blue 0
11 PM Thu 61 61 NE 3 8 5151 5810 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 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]