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

Station:

 KVBG

Date/Time UTC:

 N/A

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 Wed 75 75 NNW 4 8 N/A N/A N/A N/A N/A
1 AM Wed 72 72 NNW 3 6 N/A N/A N/A N/A N/A
2 AM Wed 68 68 NNW 3 5 N/A N/A N/A N/A N/A
3 AM Wed 64 64 NW 2 5 N/A N/A N/A N/A N/A
4 AM Wed 63 63 NW 2 4 N/A N/A N/A N/A N/A
5 AM Wed 60 60 NW 2 4 N/A N/A N/A N/A N/A
6 AM Wed 58 58 NW 2 4 N/A N/A N/A N/A N/A
7 AM Wed 62 62 NNW 2 4 N/A N/A N/A N/A N/A
8 AM Wed 68 69 NNW 1 3 N/A N/A N/A N/A N/A
9 AM Wed 73 76 N 1 3 N/A N/A N/A N/A N/A
10 AM Wed 81 86 E 1 4 N/A N/A N/A N/A N/A
11 AM Wed 85 92 SE 2 6 N/A N/A N/A N/A N/A
12 Noon Wed 88 96 SE 3 8 N/A N/A N/A N/A N/A
1 PM Wed 91 99 SE 4 10 N/A N/A N/A N/A N/A
2 PM Wed 94 102 SE 4 11 N/A N/A N/A N/A N/A
3 PM Wed 96 102 SE 4 12 N/A N/A N/A N/A N/A
4 PM Wed 96 100 SE 4 12 N/A N/A N/A N/A N/A
5 PM Wed 98 101 SE 5 12 N/A N/A N/A N/A N/A
6 PM Wed 97 98 SE 6 12 N/A N/A N/A N/A N/A
7 PM Wed 96 96 SE 4 10 N/A N/A N/A N/A N/A
8 PM Wed 92 92 N 5 12 N/A N/A N/A N/A N/A
9 PM Wed 86 86 N 8 13 N/A N/A N/A N/A N/A
10 PM Wed 83 83 N 8 13 N/A N/A N/A N/A N/A
11 PM Wed 80 80 NNW 5 12 N/A N/A N/A N/A N/A
12 Midnight Thu 76 76 NNW 5 11 N/A N/A N/A N/A N/A
1 AM Thu 73 73 NNW 6 11 N/A N/A N/A N/A N/A
2 AM Thu 70 70 NNW 5 10 N/A N/A N/A N/A N/A
3 AM Thu 65 65 N 5 10 N/A N/A N/A N/A N/A
4 AM Thu 64 64 NNW 4 9 N/A N/A N/A N/A N/A
5 AM Thu 61 61 NNW 4 8 N/A N/A N/A N/A N/A
6 AM Thu 60 60 NNW 3 5 N/A N/A N/A N/A N/A
7 AM Thu 64 64 NNW 2 4 N/A N/A N/A N/A N/A
8 AM Thu 69 70 N 2 4 N/A N/A N/A N/A N/A
9 AM Thu 73 76 N 2 4 N/A N/A N/A N/A N/A
10 AM Thu 81 86 NNE 2 5 N/A N/A N/A N/A N/A
11 AM Thu 84 91 E 3 8 N/A N/A N/A N/A N/A
12 Noon Thu 86 94 ESE 4 10 N/A N/A N/A N/A N/A
1 PM Thu 89 98 SE 6 12 N/A N/A N/A N/A N/A
2 PM Thu 92 100 SSE 6 13 N/A N/A N/A N/A N/A
3 PM Thu 94 101 SSE 5 12 N/A N/A N/A N/A N/A
4 PM Thu 95 100 S 5 11 N/A N/A N/A N/A N/A
5 PM Thu 97 100 S 5 11 N/A N/A N/A N/A N/A
6 PM Thu 96 97 SSE 4 10 N/A N/A N/A N/A N/A
7 PM Thu 94 94 S 4 10 N/A N/A N/A N/A N/A
8 PM Thu 92 92 SW 4 10 N/A N/A N/A N/A N/A
9 PM Thu 89 89 WSW 4 10 N/A N/A N/A N/A N/A
10 PM Thu 85 85 W 5 9 N/A N/A N/A N/A N/A
11 PM Thu 81 81 W 5 9 N/A N/A N/A N/A N/A
12 Midnight Fri 77 77 WNW 5 9 N/A N/A N/A N/A N/A
1 AM Fri 73 73 WNW 4 8 N/A N/A N/A N/A N/A
2 AM Fri 69 69 WNW 4 8 N/A N/A N/A N/A N/A
3 AM Fri 65 65 WNW 4 6 N/A N/A N/A N/A N/A
4 AM Fri 63 63 WNW 3 6 N/A N/A N/A N/A N/A
5 AM Fri 62 62 WNW 3 5 N/A N/A N/A N/A N/A
6 AM Fri 64 64 NW 3 4 N/A N/A N/A N/A N/A
7 AM Fri 68 68 NW 2 4 N/A N/A N/A N/A N/A
8 AM Fri 73 74 NW 2 4 N/A N/A N/A N/A N/A
9 AM Fri 78 81 W 2 4 N/A N/A N/A N/A N/A
10 AM Fri 83 88 S 2 5 N/A N/A N/A N/A N/A
11 AM Fri 88 95 SE 2 6 N/A N/A N/A N/A N/A
12 Noon Fri 91 99 SSE 3 8 N/A N/A N/A N/A N/A
1 PM Fri 93 101 S 3 10 N/A N/A N/A N/A N/A
2 PM Fri 95 102 SSW 4 11 N/A N/A N/A N/A N/A
3 PM Fri 97 103 SW 5 11 N/A N/A N/A N/A N/A
4 PM Fri 98 102 W 5 11 N/A N/A N/A N/A N/A
5 PM Fri 98 100 WNW 6 11 N/A N/A N/A N/A N/A
6 PM Fri 97 98 WNW 6 11 N/A N/A N/A N/A N/A
7 PM Fri 95 95 W 6 12 N/A N/A N/A N/A N/A
8 PM Fri 92 92 W 6 12 N/A N/A N/A N/A N/A
9 PM Fri 89 89 W 6 12 N/A N/A N/A N/A N/A
10 PM Fri 85 85 W 8 12 N/A N/A N/A N/A N/A
11 PM Fri 81 81 W 8 12 N/A N/A N/A N/A N/A
12 Midnight Sat 77 77 W 8 11 N/A N/A N/A N/A N/A
1 AM Sat 73 73 W 6 10 N/A N/A N/A N/A N/A
2 AM Sat 69 69 W 5 9 N/A N/A N/A N/A N/A
3 AM Sat 65 65 W 5 8 N/A N/A N/A N/A N/A
4 AM Sat 63 63 WNW 4 8 N/A N/A N/A N/A N/A
5 AM Sat 62 62 WNW 4 6 N/A N/A N/A N/A N/A
6 AM Sat 64 64 WNW 3 5 N/A N/A N/A N/A N/A
7 AM Sat 68 68 NW 3 4 N/A N/A N/A N/A N/A
8 AM Sat 73 74 NW 2 4 N/A N/A N/A N/A N/A
9 AM Sat 78 81 N 2 4 N/A N/A N/A N/A N/A
10 AM Sat 83 88 ENE 2 5 N/A N/A N/A N/A N/A
11 AM Sat 88 95 E 2 6 N/A N/A N/A N/A N/A
12 Noon Sat 91 99 SE 3 9 N/A N/A N/A N/A N/A
1 PM Sat 93 101 SSW 5 12 N/A N/A N/A N/A N/A
2 PM Sat 95 102 SW 6 14 N/A N/A N/A N/A N/A
3 PM Sat 97 103 WSW 8 16 N/A N/A N/A N/A N/A
4 PM Sat 97 101 WSW 9 16 N/A N/A N/A N/A N/A
5 PM Sat 96 98 W 10 16 N/A N/A N/A N/A N/A
6 PM Sat 94 95 W 10 17 N/A N/A N/A N/A N/A
7 PM Sat 92 92 W 10 18 N/A N/A N/A N/A N/A
8 PM Sat 89 89 WNW 10 18 N/A N/A N/A N/A N/A
9 PM Sat 86 86 W 10 18 N/A N/A N/A N/A N/A
10 PM Sat 83 83 W 10 16 N/A N/A N/A N/A N/A
11 PM Sat 79 79 W 9 14 N/A N/A N/A N/A N/A
12 Midnight Sun 75 75 W 8 12 N/A N/A N/A N/A N/A
1 AM Sun 70 70 WNW 5 11 N/A N/A N/A N/A N/A
2 AM Sun 67 67 WNW 4 9 N/A N/A N/A N/A N/A
3 AM Sun 64 64 WNW 3 8 N/A N/A N/A N/A N/A
4 AM Sun 63 63 WNW 3 8 N/A N/A N/A N/A N/A
5 AM Sun 63 63 WNW 3 6 N/A N/A N/A N/A N/A
6 AM Sun 66 66 NW 3 5 N/A N/A N/A N/A N/A
7 AM Sun 70 70 NW 2 4 N/A N/A N/A N/A N/A
8 AM Sun 75 77 NW 2 4 N/A N/A N/A N/A N/A
9 AM Sun 80 83 NNW 2 4 N/A N/A N/A N/A N/A
10 AM Sun 84 89 N 2 5 N/A N/A N/A N/A N/A
11 AM Sun 88 95 N 2 6 N/A N/A N/A N/A N/A
12 Noon Sun 91 100 NNW 3 9 N/A N/A N/A N/A N/A
1 PM Sun 93 102 WNW 4 12 N/A N/A N/A N/A N/A
2 PM Sun 94 102 W 5 14 N/A N/A N/A N/A N/A
3 PM Sun 95 102 W 6 14 N/A N/A N/A N/A N/A
4 PM Sun 96 101 W 8 13 N/A N/A N/A N/A N/A
5 PM Sun 96 98 W 9 13 N/A N/A N/A N/A N/A
6 PM Sun 95 96 W 9 14 N/A N/A N/A N/A N/A
7 PM Sun 92 92 WNW 9 16 N/A N/A N/A N/A N/A
8 PM Sun 89 89 NW 9 17 N/A N/A N/A N/A N/A
9 PM Sun 86 86 NW 8 17 N/A N/A N/A N/A N/A
10 PM Sun 83 83 NW 8 14 N/A N/A N/A N/A N/A
11 PM Sun 79 79 WNW 6 13 N/A N/A N/A N/A N/A
12 Midnight Mon 75 75 NW 5 11 N/A N/A N/A N/A N/A
1 AM Mon 71 71 NW 5 9 N/A N/A N/A N/A N/A
2 AM Mon 67 67 NW 4 8 N/A N/A N/A N/A N/A
3 AM Mon 64 64 NW 4 6 N/A N/A N/A N/A N/A
4 AM Mon 62 62 NW 3 6 N/A N/A N/A N/A N/A
5 AM Mon 62 62 NW 3 6 N/A N/A N/A N/A N/A
6 AM Mon 65 65 NW 3 6 N/A N/A N/A N/A N/A
7 AM Mon 70 70 NNW 2 5 N/A N/A N/A N/A N/A
8 AM Mon 75 76 NNW 2 5 N/A N/A N/A N/A N/A
9 AM Mon 80 83 N 2 5 N/A N/A N/A N/A N/A
10 AM Mon 85 90 NE 3 5 N/A N/A N/A N/A N/A
11 AM Mon 89 96 ENE 3 6 N/A N/A N/A N/A N/A
12 Noon Mon 92 101 E 3 8 N/A N/A N/A N/A N/A
1 PM Mon 93 102 SE 4 10 N/A N/A N/A N/A N/A
2 PM Mon 94 102 SSE 4 11 N/A N/A N/A N/A N/A
3 PM Mon 95 102 S 5 12 N/A N/A N/A N/A N/A
4 PM Mon 96 101 SW 6 12 N/A N/A N/A N/A N/A
5 PM Mon 95 97 WSW 8 12 N/A N/A N/A N/A N/A
6 PM Mon 93 94 W 8 13 N/A N/A N/A N/A N/A
7 PM Mon 91 91 WNW 8 13 N/A N/A N/A N/A N/A
8 PM Mon 88 88 WNW 6 13 N/A N/A N/A N/A N/A
9 PM Mon 85 85 WNW 6 12 N/A N/A N/A N/A N/A
10 PM Mon 82 82 WNW 5 11 N/A N/A N/A N/A N/A

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]