Detailed Predictions for: St John
Launch Lat, Long, Altitude (f): 39.424433, -122.689342, 6350
LZ Altitude (f): 1185
Sounding

Station:

 KOAK

Date/Time:

 5 DEC 2023

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 51 51 WSW 2 4 6501 6350 0 Blue 0
1 AM Tue 51 51 WSW 1 3 6501 6350 0 Blue 0
2 AM Tue 51 51 W 1 2 6501 6350 0 Blue 0
3 AM Tue 50 50 W 1 2 6280 6350 0 Blue 0
4 AM Tue 50 50 W 1 3 6280 6350 0 Blue 0
5 AM Tue 50 50 NW 0 1 6280 6350 0 Blue 0
6 AM Tue 48 48 N 2 2 6280 6350 0 Blue 0
7 AM Tue 49 49 W 1 3 6280 6350 0 Blue 0
8 AM Tue 49 49 W 2 4 6280 6350 0 Blue 0
9 AM Tue 49 49 W 1 2 6280 6350 0 Blue 0
10 AM Tue 50 50 ESE 0 1 6280 6350 0 Blue 0
11 AM Tue 52 53 ESE 2 2 7264 6350 0 Blue 2
12 Noon Tue 58 58 ESE 2 3 9987 8040 1690 Blue 7
1 PM Tue 60 60 ESE 3 3 10462 9593 3243 Blue 9
2 PM Tue 61 61 ESE 3 4 10808 9962 3612 Blue 10
3 PM Tue 62 62 ESE 3 4 11150 10178 3828 Blue 11
4 PM Tue 63 63 ESE 3 3 11608 10416 4066 Blue 12
5 PM Tue 60 60 ESE 2 4 10462 9593 3243 Blue 9
6 PM Tue 59 59 SSE 1 3 10205 8765 2415 Blue 8
7 PM Tue 56 56 SW 2 5 8835 7252 902 Blue 5
8 PM Tue 54 54 SW 2 5 7666 6500 150 Blue 3
9 PM Tue 53 53 WSW 2 4 7264 6350 0 Blue 2
10 PM Tue 52 52 WSW 2 5 6856 6350 0 Blue 1
11 PM Tue 51 51 WSW 2 5 6501 6350 0 Blue 0
12 Midnight Wed 49 49 SW 1 3 6280 6350 0 Blue 0
1 AM Wed 48 48 SW 1 3 6280 6350 0 Blue 0
2 AM Wed 51 51 SW 2 4 6501 6350 0 Blue 0
3 AM Wed 47 47 SW 2 5 6280 6350 0 Blue 0
4 AM Wed 47 47 WSW 3 7 6280 6350 0 Blue 0
5 AM Wed 51 51 SW 3 7 6501 6350 0 Blue 0
6 AM Wed 47 47 SSW 3 7 6280 6350 0 Blue 0
7 AM Wed 47 47 SSW 4 8 6280 6350 0 Blue 0
8 AM Wed 48 48 SW 4 9 6280 6350 0 Blue 0
9 AM Wed 48 48 WSW 4 9 6280 6350 0 Blue 0
10 AM Wed 51 51 SSW 3 4 6501 6350 0 Blue 0
11 AM Wed 50 50 SSE 4 5 6280 6350 0 Blue 0
12 Noon Wed 51 51 S 5 6 6501 6350 0 Blue 0
1 PM Wed 51 51 SSW 6 7 6501 6350 0 Blue 0
2 PM Wed 55 56 SW 7 8 8835 7252 902 Blue 5
3 PM Wed 56 56 WSW 10 12 8835 7252 902 Blue 5
4 PM Wed 56 56 WSW 8 10 8835 7252 902 Blue 5
5 PM Wed 53 53 WSW 7 9 7264 6350 0 Blue 2
6 PM Wed 49 49 WSW 6 11 6280 6350 0 Blue 0
7 PM Wed 47 47 SW 6 11 6280 6350 0 Blue 0
8 PM Wed 47 47 SW 6 12 6280 6350 0 Blue 0
9 PM Wed 45 45 WSW 7 13 6280 6350 0 Blue 0
10 PM Wed 45 45 WSW 7 13 6280 6350 0 Blue 0
11 PM Wed 45 45 WSW 8 14 6280 6350 0 Blue 0
12 Midnight Thu 44 44 WSW 8 15 6280 6350 0 Blue 0
1 AM Thu 43 43 WSW 8 14 6280 6350 0 Blue 0
2 AM Thu 44 44 WSW 6 11 6280 6350 0 Blue 0
3 AM Thu 40 40 W 5 11 6280 6350 0 Blue 0
4 AM Thu 39 39 W 5 11 6280 6350 0 Blue 0
5 AM Thu 42 42 W 5 11 6280 6350 0 Blue 0
6 AM Thu 36 36 W 4 10 6280 6350 0 Blue 0
7 AM Thu 36 36 W 4 10 6280 6350 0 Blue 0
8 AM Thu 40 40 W 4 9 6280 6350 0 Blue 0
9 AM Thu 38 38 W 4 8 6280 6350 0 Blue 0
10 AM Thu 45 45 W 2 3 6280 6350 0 Blue 0
11 AM Thu 44 45 W 0 1 6280 6350 0 Blue 0
12 Noon Thu 51 53 S 0 0 7264 6350 0 Blue 2
1 PM Thu 53 55 SSE 1 1 8062 6849 499 Blue 4
2 PM Thu 49 49 SSE 2 2 6280 6350 0 Blue 0
3 PM Thu 55 55 SSW 2 3 8062 6849 499 Blue 4
4 PM Thu 54 54 WSW 5 5 7666 6500 150 Blue 3
5 PM Thu 47 47 WSW 5 8 6280 6350 0 Blue 0
6 PM Thu 43 43 WSW 6 12 6280 6350 0 Blue 0
7 PM Thu 42 42 WSW 5 10 6280 6350 0 Blue 0
8 PM Thu 43 43 WSW 6 12 6280 6350 0 Blue 0
9 PM Thu 42 42 W 5 10 6280 6350 0 Blue 0
10 PM Thu 41 41 W 5 9 6280 6350 0 Blue 0
11 PM Thu 41 41 W 4 8 6280 6350 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]