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:

250217/1200

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 Mon 40 40 WNW 13 20 4056 4500 0 Blue 0
1 AM Mon 39 39 NW 13 19 4056 4500 0 Blue 0
2 AM Mon 39 39 NW 13 18 4056 4500 0 Blue 0
3 AM Mon 38 38 NW 13 18 4056 4500 0 Blue 0
4 AM Mon 36 36 NW 12 17 4056 4500 0 Blue 0
5 AM Mon 34 34 NW 11 16 4056 4500 0 Blue 0
6 AM Mon 34 34 NW 10 14 4056 4500 0 Blue 0
7 AM Mon 32 32 NW 10 13 4056 4500 0 Blue 0
8 AM Mon 37 37 WNW 8 12 4056 4500 0 Blue 0
9 AM Mon 45 46 NNW 5 10 4056 4500 0 Blue 0
10 AM Mon 49 50 N 5 9 4391 4500 0 Blue 0
11 AM Mon 52 54 N 5 10 4902 4594 94 Blue 3
12 Noon Mon 55 57 NNW 6 11 6154 4896 396 Blue 6
1 PM Mon 56 57 NNW 8 12 6154 4896 396 Blue 6
2 PM Mon 57 58 NNW 10 14 6574 5304 804 Blue 7
3 PM Mon 58 58 NNW 10 16 6574 5304 804 Blue 7
4 PM Mon 56 56 NNW 10 17 5727 4713 213 Blue 5
5 PM Mon 53 53 NNW 11 19 4714 4500 0 Blue 2
6 PM Mon 50 50 NNW 11 18 4391 4500 0 Blue 0
7 PM Mon 46 46 NNW 10 17 4056 4500 0 Blue 0
8 PM Mon 43 43 NNW 11 17 4056 4500 0 Blue 0
9 PM Mon 41 41 NNW 11 18 4056 4500 0 Blue 0
10 PM Mon 39 39 NNW 11 17 4056 4500 0 Blue 0
11 PM Mon 37 37 NNW 10 17 4056 4500 0 Blue 0
12 Midnight Tue 36 36 NNW 10 16 4056 4500 0 Blue 0
1 AM Tue 35 35 NNW 10 14 4056 4500 0 Blue 0
2 AM Tue 35 35 NNW 10 13 4056 4500 0 Blue 0
3 AM Tue 34 34 NNW 10 13 4056 4500 0 Blue 0
4 AM Tue 32 32 NNW 9 13 4056 4500 0 Blue 0
5 AM Tue 31 31 NW 8 11 4056 4500 0 Blue 0
6 AM Tue 29 29 NW 6 10 4056 4500 0 Blue 0
7 AM Tue 28 28 NW 5 9 4056 4500 0 Blue 0
8 AM Tue 32 32 NNW 4 8 4056 4500 0 Blue 0
9 AM Tue 38 39 NNW 3 6 4056 4500 0 Blue 0
10 AM Tue 44 46 N 2 5 4056 4500 0 Blue 0
11 AM Tue 48 50 N 2 4 4391 4500 0 Blue 0
12 Noon Tue 51 54 NE 2 4 4902 4594 94 Blue 3
1 PM Tue 53 56 NE 2 4 5727 4713 213 Blue 5
2 PM Tue 55 57 NE 2 4 6154 4896 396 Blue 6
3 PM Tue 56 57 N 2 5 6154 4896 396 Blue 6
4 PM Tue 56 56 N 2 5 5727 4713 213 Blue 5
5 PM Tue 54 54 NNW 2 5 4902 4594 94 Blue 3
6 PM Tue 51 51 W 2 5 4594 4500 0 Blue 0
7 PM Tue 48 48 WSW 2 5 4056 4500 0 Blue 0
8 PM Tue 46 46 WSW 2 5 4056 4500 0 Blue 0
9 PM Tue 44 44 W 3 5 4056 4500 0 Blue 0
10 PM Tue 42 42 W 3 5 4056 4500 0 Blue 0
11 PM Tue 41 41 W 3 5 4056 4500 0 Blue 0
12 Midnight Wed 39 39 W 4 5 4056 4500 0 Blue 0
1 AM Wed 38 38 W 4 5 4056 4500 0 Blue 0
2 AM Wed 36 36 W 4 5 4056 4500 0 Blue 0
3 AM Wed 35 35 W 4 5 4056 4500 0 Blue 0
4 AM Wed 34 34 W 4 5 4056 4500 0 Blue 0
5 AM Wed 34 34 W 4 5 4056 4500 0 Blue 0
6 AM Wed 36 36 W 4 5 4056 4500 0 Blue 0
7 AM Wed 38 38 W 4 5 4056 4500 0 Blue 0
8 AM Wed 42 42 WSW 3 5 4056 4500 0 Blue 0
9 AM Wed 47 47 SW 3 5 4056 4500 0 Blue 0
10 AM Wed 51 52 SSW 3 6 4654 4500 0 Blue 1
11 AM Wed 54 56 SW 4 9 5727 4713 213 Blue 5
12 Noon Wed 57 60 SW 5 11 7402 6130 1630 Blue 9
1 PM Wed 59 62 SW 8 13 8257 6953 2453 Blue 11
2 PM Wed 60 62 WSW 10 17 8257 6953 2453 Blue 11
3 PM Wed 61 62 WSW 11 19 8257 6953 2453 Blue 11
4 PM Wed 60 60 W 12 21 7402 6130 1630 Blue 9
5 PM Wed 57 57 W 12 21 6154 4896 396 Blue 6
6 PM Wed 54 54 WNW 12 20 4902 4594 94 Blue 3
7 PM Wed 50 50 WNW 12 19 4391 4500 0 Blue 0
8 PM Wed 47 47 WNW 12 19 4056 4500 0 Blue 0
9 PM Wed 44 44 WNW 11 18 4056 4500 0 Blue 0
10 PM Wed 41 41 WNW 11 18 4056 4500 0 Blue 0
11 PM Wed 39 39 WNW 11 18 4056 4500 0 Blue 0
12 Midnight Thu 37 37 NW 11 17 4056 4500 0 Blue 0
1 AM Thu 35 35 NW 11 17 4056 4500 0 Blue 0
2 AM Thu 34 34 NW 11 16 4056 4500 0 Blue 0
3 AM Thu 33 33 NW 10 16 4056 4500 0 Blue 0
4 AM Thu 32 32 NW 10 14 4056 4500 0 Blue 0
5 AM Thu 30 30 NW 9 13 4056 4500 0 Blue 0
6 AM Thu 28 28 WNW 9 12 4056 4500 0 Blue 0
7 AM Thu 28 28 WNW 8 11 4056 4500 0 Blue 0
8 AM Thu 33 33 NW 6 10 4056 4500 0 Blue 0
9 AM Thu 39 40 NNW 5 10 4056 4500 0 Blue 0
10 AM Thu 45 47 NNW 5 10 4056 4500 0 Blue 0
11 AM Thu 48 51 NNW 5 10 4594 4500 0 Blue 0
12 Noon Thu 51 54 N 5 10 4902 4594 94 Blue 3
1 PM Thu 52 55 N 6 11 5316 4654 154 Blue 4
2 PM Thu 54 56 N 8 12 5727 4713 213 Blue 5
3 PM Thu 55 56 N 9 14 5727 4713 213 Blue 5
4 PM Thu 54 54 N 10 16 4902 4594 94 Blue 3
5 PM Thu 51 51 N 10 17 4594 4500 0 Blue 0
6 PM Thu 47 47 NNW 10 17 4056 4500 0 Blue 0
7 PM Thu 43 43 NNW 10 17 4056 4500 0 Blue 0
8 PM Thu 41 41 NNW 10 17 4056 4500 0 Blue 0
9 PM Thu 39 39 NNW 9 16 4056 4500 0 Blue 0
10 PM Thu 38 38 NNW 9 14 4056 4500 0 Blue 0
11 PM Thu 36 36 NNW 9 13 4056 4500 0 Blue 0
12 Midnight Fri 34 34 NW 8 12 4056 4500 0 Blue 0
1 AM Fri 33 33 NW 8 11 4056 4500 0 Blue 0
2 AM Fri 32 32 NW 6 10 4056 4500 0 Blue 0
3 AM Fri 32 32 NW 6 10 4056 4500 0 Blue 0
4 AM Fri 31 31 NW 5 9 4056 4500 0 Blue 0
5 AM Fri 29 29 NW 5 9 4056 4500 0 Blue 0
6 AM Fri 27 27 NW 4 8 4056 4500 0 Blue 0
7 AM Fri 27 27 NW 4 8 4056 4500 0 Blue 0
8 AM Fri 32 32 NNW 3 6 4056 4500 0 Blue 0
9 AM Fri 39 40 N 2 6 4056 4500 0 Blue 0
10 AM Fri 45 47 N 2 5 4056 4500 0 Blue 0
11 AM Fri 49 52 N 2 5 4654 4500 0 Blue 1
12 Noon Fri 52 55 N 3 5 5316 4654 154 Blue 4
1 PM Fri 54 57 N 3 5 6154 4896 396 Blue 6
2 PM Fri 56 58 NNW 3 6 6574 5304 804 Blue 7
3 PM Fri 57 58 W 4 6 6574 5304 804 Blue 7
4 PM Fri 57 57 SW 4 8 6154 4896 396 Blue 6
5 PM Fri 55 55 WSW 4 8 5316 4654 154 Blue 4
6 PM Fri 51 51 W 4 8 4594 4500 0 Blue 0
7 PM Fri 48 48 W 4 8 4056 4500 0 Blue 0
8 PM Fri 45 45 W 4 8 4056 4500 0 Blue 0
9 PM Fri 43 43 WNW 4 8 4056 4500 0 Blue 0
10 PM Fri 41 41 WNW 4 8 4056 4500 0 Blue 0
11 PM Fri 39 39 WNW 4 8 4056 4500 0 Blue 0
12 Midnight Sat 38 38 WNW 4 6 4056 4500 0 Blue 0
1 AM Sat 37 37 WNW 4 6 4056 4500 0 Blue 0
2 AM Sat 36 36 WNW 4 6 4056 4500 0 Blue 0
3 AM Sat 35 35 WNW 5 6 4056 4500 0 Blue 0
4 AM Sat 35 35 WNW 5 6 4056 4500 0 Blue 0
5 AM Sat 34 34 WNW 5 6 4056 4500 0 Blue 0
6 AM Sat 34 34 WNW 4 5 4056 4500 0 Blue 0
7 AM Sat 35 35 WNW 3 5 4056 4500 0 Blue 0
8 AM Sat 39 39 NW 2 4 4056 4500 0 Blue 0
9 AM Sat 45 46 NNW 1 3 4056 4500 0 Blue 0
10 AM Sat 51 53 N 1 3 4714 4500 0 Blue 2
11 AM Sat 55 57 NNW 1 3 6154 4896 396 Blue 6
12 Noon Sat 58 61 W 2 4 7825 6545 2045 Blue 10
1 PM Sat 60 63 WSW 2 5 8681 7361 2861 Blue 12
2 PM Sat 62 64 SW 2 5 9099 7777 3277 Blue 13
3 PM Sat 63 64 SSW 3 6 9099 7777 3277 Blue 13
4 PM Sat 62 62 S 3 6 8257 6953 2453 Blue 11
5 PM Sat 59 59 SSW 3 6 6987 5710 1210 Blue 8
6 PM Sat 56 56 WSW 4 6 5727 4713 213 Blue 5
7 PM Sat 52 52 W 4 6 4654 4500 0 Blue 1
8 PM Sat 49 49 W 4 6 4179 4500 0 Blue 0
9 PM Sat 47 47 W 4 6 4056 4500 0 Blue 0
10 PM Sat 45 45 W 4 6 4056 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]