Detailed Predictions for: Chalk Bluffs
Launch Altitude (f): 4500
LZ Altitude (f): 4220
Sounding

Station:

KVBG

Date/Time:

18 NOV 2019

Temp/Wind data from:

NOAA Digital Forecast

Site Forecasts
Time
(Local)
High
Temp

Puddle
Temp

Wind
(mph)
Thermal
Ceiling

(ft)
Soaring
Ceiling

(ft)
Above
Launch

(ft)
Thermal
Type
Thermal
Index

(F)
4 AM Mon 39 39 NW 3 2575 4500 0 Blue 0
5 AM Mon 38 38 NW 3 2575 4500 0 Blue 0
6 AM Mon 41 41 SW 3 2575 4500 0 Blue 0
7 AM Mon 38 38 SW 2 2575 4500 0 Blue 0
8 AM Mon 47 47 SW 3 2575 4500 0 Blue 0
9 AM Mon 58 59 SW 3 2575 4500 0 Blue 0
10 AM Mon 63 65 SE 3 2575 4500 0 Blue 0
11 AM Mon 69 71 SE 3 6174 4500 0 Blue 1
12 Noon Mon 72 74 SE 5 7328 6111 1611 Blue 4
1 PM Mon 76 78 SE 5 7825 7390 2890 Blue 8
2 PM Mon 76 77 SE 6 7533 7322 2822 Blue 7
3 PM Mon 77 77 S 6 7533 7322 2822 Blue 7
4 PM Mon 72 72 S 6 6757 4500 0 Blue 2
5 PM Mon 63 63 SE 6 2575 4500 0 Blue 0
6 PM Mon 58 58 SE 6 2575 4500 0 Blue 0
7 PM Mon 53 53 SE 6 2575 4500 0 Blue 0
8 PM Mon 49 49 SE 5 2575 4500 0 Blue 0
9 PM Mon 46 46 S 3 2575 4500 0 Blue 0
10 PM Mon 44 44 S 3 2575 4500 0 Blue 0
11 PM Mon 43 43 SW 3 2575 4500 0 Blue 0
12 Midnight Tue 43 43 W 3 2575 4500 0 Blue 0
1 AM Tue 41 41 NW 3 2575 4500 0 Blue 0
2 AM Tue 40 40 NW 3 2575 4500 0 Blue 0
3 AM Tue 39 39 W 3 2575 4500 0 Blue 0
4 AM Tue 39 39 W 5 2575 4500 0 Blue 0
5 AM Tue 38 38 W 5 2575 4500 0 Blue 0
6 AM Tue 38 38 SW 5 2575 4500 0 Blue 0
7 AM Tue 39 39 SW 6 2575 4500 0 Blue 0
8 AM Tue 47 47 SW 6 2575 4500 0 Blue 0
9 AM Tue 53 53 S 6 2575 4500 0 Blue 0
10 AM Tue 58 58 SE 6 2575 4500 0 Blue 0
11 AM Tue 61 61 S 7 2575 4500 0 Blue 0
12 Noon Tue 64 64 SW 8 2575 4500 0 Blue 0
1 PM Tue 65 65 W 9 2575 4500 0 Blue 0
2 PM Tue 66 66 SW 10 2806 4500 0 Blue 0
3 PM Tue 65 65 SE 10 2575 4500 0 Blue 0
4 PM Tue 62 62 SE 10 2575 4500 0 Blue 0
5 PM Tue 58 58 E 8 2575 4500 0 Blue 0
6 PM Tue 52 52 N 7 2575 4500 0 Blue 0
7 PM Tue 47 47 NW 5 2575 4500 0 Blue 0
8 PM Tue 44 44 NW 5 2575 4500 0 Blue 0
9 PM Tue 42 42 NW 5 2575 4500 0 Blue 0
10 PM Tue 41 41 NW 6 2575 4500 0 Blue 0
11 PM Tue 41 41 NW 6 2575 4500 0 Blue 0
12 Midnight Wed 41 41 NW 7 2575 4500 0 Blue 0
1 AM Wed 40 40 NW 7 2575 4500 0 Blue 0
2 AM Wed 40 40 N 7 2575 4500 0 Blue 0
3 AM Wed 39 39 N 8 2575 4500 0 Blue 0
4 AM Wed 37 37 N 8 2575 4500 0 Blue 0
5 AM Wed 36 36 N 8 2575 4500 0 Blue 0
6 AM Wed 35 35 NW 8 2575 4500 0 Blue 0
7 AM Wed 35 35 NW 8 2575 4500 0 Blue 0
8 AM Wed 37 37 NW 8 2575 4500 0 Blue 0
9 AM Wed 40 40 N 9 2575 4500 0 Blue 0
10 AM Wed 43 43 N 9 2575 4500 0 Blue 0
11 AM Wed 45 45 N 9 2575 4500 0 Blue 0
12 Noon Wed 46 46 N 10 2575 4500 0 Blue 0
1 PM Wed 47 47 N 10 2575 4500 0 Blue 0
2 PM Wed 48 48 N 10 2575 4500 0 Blue 0
3 PM Wed 48 48 N 10 2575 4500 0 Blue 0
4 PM Wed 47 47 N 10 2575 4500 0 Blue 0
5 PM Wed 44 44 N 12 2575 4500 0 Blue 0
6 PM Wed 40 40 NW 12 2575 4500 0 Blue 0
7 PM Wed 37 37 W 12 2575 4500 0 Blue 0
8 PM Wed 35 35 NW 10 2575 4500 0 Blue 0
9 PM Wed 34 34 NE 8 2575 4500 0 Blue 0
10 PM Wed 33 33 NE 6 2575 4500 0 Blue 0
11 PM Wed 33 33 NE 6 2575 4500 0 Blue 0
12 Midnight Thu 33 33 NE 6 2575 4500 0 Blue 0
1 AM Thu 33 33 NE 6 2575 4500 0 Blue 0
2 AM Thu 33 33 NE 6 2575 4500 0 Blue 0
3 AM Thu 31 31 NE 6 2575 4500 0 Blue 0
4 AM Thu 30 30 NE 6 2575 4500 0 Blue 0
5 AM Thu 29 29 NE 6 2575 4500 0 Blue 0
6 AM Thu 28 28 NE 6 2575 4500 0 Blue 0
7 AM Thu 29 29 NE 6 2575 4500 0 Blue 0
8 AM Thu 33 33 NE 6 2575 4500 0 Blue 0
9 AM Thu 37 37 NE 5 2575 4500 0 Blue 0
10 AM Thu 42 43 NE 5 2575 4500 0 Blue 0
11 AM Thu 45 46 NE 5 2575 4500 0 Blue 0
12 Noon Thu 46 47 NE 5 2575 4500 0 Blue 0
1 PM Thu 48 49 NE 5 2575 4500 0 Blue 0
2 PM Thu 49 49 NE 5 2575 4500 0 Blue 0
3 PM Thu 49 49 NE 6 2575 4500 0 Blue 0
4 PM Thu 48 48 N 6 2575 4500 0 Blue 0
5 PM Thu 44 44 N 6 2575 4500 0 Blue 0
6 PM Thu 39 39 N 6 2575 4500 0 Blue 0
7 PM Thu 35 35 N 6 2575 4500 0 Blue 0
8 PM Thu 32 32 N 5 2575 4500 0 Blue 0
9 PM Thu 31 31 W 5 2575 4500 0 Blue 0
10 PM Thu 31 31 SW 3 2575 4500 0 Blue 0
11 PM Thu 30 30 SW 3 2575 4500 0 Blue 0
12 Midnight Fri 30 30 SW 3 2575 4500 0 Blue 0
1 AM Fri 30 30 SW 3 2575 4500 0 Blue 0
2 AM Fri 29 29 SW 3 2575 4500 0 Blue 0
3 AM Fri 28 28 W 2 2575 4500 0 Blue 0
4 AM Fri 28 28 W 2 2575 4500 0 Blue 0
5 AM Fri 26 26 W 2 2575 4500 0 Blue 0
6 AM Fri 26 26 W 2 2575 4500 0 Blue 0
7 AM Fri 28 28 W 2 2575 4500 0 Blue 0
8 AM Fri 32 32 W 3 2575 4500 0 Blue 0
9 AM Fri 38 39 W 5 2575 4500 0 Blue 0
10 AM Fri 43 44 W 6 2575 4500 0 Blue 0
11 AM Fri 47 49 W 6 2575 4500 0 Blue 0
12 Noon Fri 49 51 W 6 2575 4500 0 Blue 0
1 PM Fri 50 52 W 6 2575 4500 0 Blue 0
2 PM Fri 51 52 W 6 2575 4500 0 Blue 0
3 PM Fri 51 51 SW 5 2575 4500 0 Blue 0
4 PM Fri 49 49 S 5 2575 4500 0 Blue 0
5 PM Fri 45 45 S 5 2575 4500 0 Blue 0
6 PM Fri 40 40 S 5 2575 4500 0 Blue 0
7 PM Fri 35 35 S 5 2575 4500 0 Blue 0
8 PM Fri 32 32 SW 5 2575 4500 0 Blue 0
9 PM Fri 31 31 W 3 2575 4500 0 Blue 0
10 PM Fri 30 30 NW 3 2575 4500 0 Blue 0
11 PM Fri 30 30 NW 3 2575 4500 0 Blue 0
12 Midnight Sat 29 29 NW 3 2575 4500 0 Blue 0
1 AM Sat 29 29 NW 3 2575 4500 0 Blue 0
2 AM Sat 29 29 W 3 2575 4500 0 Blue 0
3 AM Sat 28 28 W 2 2575 4500 0 Blue 0
4 AM Sat 27 27 W 2 2575 4500 0 Blue 0
5 AM Sat 26 26 W 2 2575 4500 0 Blue 0
6 AM Sat 26 26 W 2 2575 4500 0 Blue 0
7 AM Sat 28 28 W 2 2575 4500 0 Blue 0
8 AM Sat 33 33 W 3 2575 4500 0 Blue 0
9 AM Sat 39 40 N 3 2575 4500 0 Blue 0
10 AM Sat 45 46 NE 5 2575 4500 0 Blue 0
11 AM Sat 49 51 NE 5 2575 4500 0 Blue 0
12 Noon Sat 51 53 NE 5 2575 4500 0 Blue 0
1 PM Sat 53 55 NE 5 2575 4500 0 Blue 0
2 PM Sat 54 55 N 5 2575 4500 0 Blue 0
3 PM Sat 54 54 N 5 2575 4500 0 Blue 0
4 PM Sat 52 52 NW 5 2575 4500 0 Blue 0
5 PM Sat 47 47 NW 5 2575 4500 0 Blue 0
6 PM Sat 42 42 NW 5 2575 4500 0 Blue 0
7 PM Sat 36 36 NW 5 2575 4500 0 Blue 0
8 PM Sat 33 33 NW 5 2575 4500 0 Blue 0
9 PM Sat 31 31 W 3 2575 4500 0 Blue 0
10 PM Sat 30 30 W 3 2575 4500 0 Blue 0
11 PM Sat 30 30 W 3 2575 4500 0 Blue 0
12 Midnight Sun 30 30 W 3 2575 4500 0 Blue 0
1 AM Sun 30 30 W 3 2575 4500 0 Blue 0
2 AM Sun 30 30 W 3 2575 4500 0 Blue 0
3 AM Sun 29 29 NW 2 2575 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 website.  Puddle temperatures can exceed this temperature. 

Puddle Temp: This estimate is based on the High Temp and the National Weather Service 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 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]