Detailed Predictions for: Chalk Bluffs
Launch Lat, Long, Altitude (f): 37.416328, -118.442829, 4500
LZ Altitude (f): 4220
Sounding

Station:

KVBG

Date/Time:

29 NOV 2022

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 26 26 WNW 6 13 3868 4500 0 Blue 0
1 AM Tue 25 25 WNW 5 12 3868 4500 0 Blue 0
2 AM Tue 25 25 WNW 5 12 3868 4500 0 Blue 0
3 AM Tue 24 24 WNW 5 11 3868 4500 0 Blue 0
4 AM Tue 23 23 WNW 4 10 3868 4500 0 Blue 0
5 AM Tue 23 23 WNW 4 8 3868 4500 0 Blue 0
6 AM Tue 19 19 WNW 4 8 3868 4500 0 Blue 0
7 AM Tue 15 15 NW 4 8 3868 4500 0 Blue 0
8 AM Tue 10 10 WNW 3 6 3868 4500 0 Blue 0
9 AM Tue 16 17 WNW 2 3 3868 4500 0 Blue 0
10 AM Tue 31 32 NW 1 1 3868 4500 0 Blue 0
11 AM Tue 34 36 SSW 0 0 3868 4500 0 Blue 0
12 Noon Tue 40 42 S 1 1 3912 4500 0 Blue 0
1 PM Tue 43 45 SSE 1 2 5227 4500 0 Blue 2
2 PM Tue 43 44 SSE 2 2 4978 4500 0 Blue 1
3 PM Tue 45 45 SSE 1 1 5227 4500 0 Blue 2
4 PM Tue 44 44 S 0 1 4978 4500 0 Blue 1
5 PM Tue 39 39 SSW 1 1 3868 4500 0 Blue 0
6 PM Tue 34 34 SSW 0 1 3868 4500 0 Blue 0
7 PM Tue 28 28 S 0 1 3868 4500 0 Blue 0
8 PM Tue 21 21 SSW 0 1 3868 4500 0 Blue 0
9 PM Tue 23 23 SW 0 1 3868 4500 0 Blue 0
10 PM Tue 22 22 SSW 1 2 3868 4500 0 Blue 0
11 PM Tue 14 14 SSW 1 3 3868 4500 0 Blue 0
12 Midnight Wed 30 30 SSW 1 3 3868 4500 0 Blue 0
1 AM Wed 30 30 SSW 1 3 3868 4500 0 Blue 0
2 AM Wed 19 19 SW 1 3 3868 4500 0 Blue 0
3 AM Wed 29 29 SW 1 3 3868 4500 0 Blue 0
4 AM Wed 29 29 SW 1 3 3868 4500 0 Blue 0
5 AM Wed 19 19 SW 1 3 3868 4500 0 Blue 0
6 AM Wed 29 29 SW 1 3 3868 4500 0 Blue 0
7 AM Wed 29 29 SW 1 2 3868 4500 0 Blue 0
8 AM Wed 17 17 SW 1 3 3868 4500 0 Blue 0
9 AM Wed 31 32 SSW 0 1 3868 4500 0 Blue 0
10 AM Wed 34 35 SSE 2 3 3868 4500 0 Blue 0
11 AM Wed 39 41 SE 3 4 3868 4500 0 Blue 0
12 Noon Wed 38 40 SE 4 4 3868 4500 0 Blue 0
1 PM Wed 39 41 SE 4 4 3868 4500 0 Blue 0
2 PM Wed 45 46 SSE 4 4 5844 4633 133 Blue 3
3 PM Wed 40 40 SSE 4 5 3868 4500 0 Blue 0
4 PM Wed 40 40 SSE 5 6 3868 4500 0 Blue 0
5 PM Wed 37 37 SSE 4 5 3868 4500 0 Blue 0
6 PM Wed 36 36 SSW 2 4 3868 4500 0 Blue 0
7 PM Wed 36 36 SSW 3 5 3868 4500 0 Blue 0
8 PM Wed 20 20 SSW 3 7 3868 4500 0 Blue 0
9 PM Wed 32 32 S 2 5 3868 4500 0 Blue 0
10 PM Wed 32 32 S 3 7 3868 4500 0 Blue 0
11 PM Wed 14 14 S 3 7 3868 4500 0 Blue 0
12 Midnight Thu 30 30 S 4 8 3868 4500 0 Blue 0
1 AM Thu 30 30 S 4 8 3868 4500 0 Blue 0
2 AM Thu 15 15 S 4 8 3868 4500 0 Blue 0
3 AM Thu 30 30 S 4 8 3868 4500 0 Blue 0
4 AM Thu 29 29 S 4 8 3868 4500 0 Blue 0
5 AM Thu 11 11 S 3 7 3868 4500 0 Blue 0
6 AM Thu 29 29 S 3 7 3868 4500 0 Blue 0
7 AM Thu 29 29 S 4 8 3868 4500 0 Blue 0
8 AM Thu 15 15 S 4 8 3868 4500 0 Blue 0
9 AM Thu 32 33 S 5 9 3868 4500 0 Blue 0
10 AM Thu 35 36 SSE 6 9 3868 4500 0 Blue 0
11 AM Thu 39 39 SSE 7 8 3868 4500 0 Blue 0
12 Noon Thu 39 41 S 7 8 3868 4500 0 Blue 0
1 PM Thu 40 41 S 8 10 3868 4500 0 Blue 0
2 PM Thu 45 45 S 8 10 5227 4500 0 Blue 2
3 PM Thu 40 40 S 10 12 3868 4500 0 Blue 0
4 PM Thu 39 39 S 11 13 3868 4500 0 Blue 0
5 PM Thu 39 39 S 9 13 3868 4500 0 Blue 0
6 PM Thu 34 34 S 8 13 3868 4500 0 Blue 0
7 PM Thu 33 33 S 7 12 3868 4500 0 Blue 0
8 PM Thu 33 33 S 7 11 3868 4500 0 Blue 0
9 PM Thu 31 31 S 7 10 3868 4500 0 Blue 0
10 PM Thu 31 31 S 6 10 3868 4500 0 Blue 0
11 PM Thu 35 35 SSW 4 7 3868 4500 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]