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

Station:

KVBG

Date/Time:

19 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 Tue 41 41 SW 6 3392 4500 0 Blue 0
5 AM Tue 40 40 W 5 3392 4500 0 Blue 0
6 AM Tue 39 39 SW 5 3392 4500 0 Blue 0
7 AM Tue 37 37 SW 5 3392 4500 0 Blue 0
8 AM Tue 44 44 SW 5 3392 4500 0 Blue 0
9 AM Tue 53 53 S 6 3392 4500 0 Blue 0
10 AM Tue 59 59 S 6 3392 4500 0 Blue 0
11 AM Tue 63 64 S 6 3469 4500 0 Blue 0
12 Noon Tue 67 68 S 6 6275 4500 0 Blue 3
1 PM Tue 68 69 S 7 6444 5049 549 Blue 4
2 PM Tue 68 68 S 9 6275 4500 0 Blue 3
3 PM Tue 67 67 SW 8 5826 4500 0 Blue 2
4 PM Tue 64 64 SW 7 3469 4500 0 Blue 0
5 PM Tue 58 58 S 6 3392 4500 0 Blue 0
6 PM Tue 53 53 SW 6 3392 4500 0 Blue 0
7 PM Tue 51 51 W 8 3392 4500 0 Blue 0
8 PM Tue 47 47 NW 7 3392 4500 0 Blue 0
9 PM Tue 45 45 NW 7 3392 4500 0 Blue 0
10 PM Tue 44 44 NW 7 3392 4500 0 Blue 0
11 PM Tue 43 43 NW 7 3392 4500 0 Blue 0
12 Midnight Wed 43 43 NW 7 3392 4500 0 Blue 0
1 AM Wed 43 43 NW 6 3392 4500 0 Blue 0
2 AM Wed 42 42 NW 6 3392 4500 0 Blue 0
3 AM Wed 42 42 NW 6 3392 4500 0 Blue 0
4 AM Wed 40 40 N 6 3392 4500 0 Blue 0
5 AM Wed 38 38 N 6 3392 4500 0 Blue 0
6 AM Wed 38 38 N 6 3392 4500 0 Blue 0
7 AM Wed 39 39 N 6 3392 4500 0 Blue 0
8 AM Wed 41 41 N 6 3392 4500 0 Blue 0
9 AM Wed 43 43 N 8 3392 4500 0 Blue 0
10 AM Wed 44 44 N 10 3392 4500 0 Blue 0
11 AM Wed 46 46 N 12 3392 4500 0 Blue 0
12 Noon Wed 47 47 N 10 3392 4500 0 Blue 0
1 PM Wed 47 47 N 10 3392 4500 0 Blue 0
2 PM Wed 47 47 N 10 3392 4500 0 Blue 0
3 PM Wed 47 47 N 12 3392 4500 0 Blue 0
4 PM Wed 45 45 N 12 3392 4500 0 Blue 0
5 PM Wed 42 42 N 12 3392 4500 0 Blue 0
6 PM Wed 39 39 N 12 3392 4500 0 Blue 0
7 PM Wed 36 36 N 10 3392 4500 0 Blue 0
8 PM Wed 34 34 N 9 3392 4500 0 Blue 0
9 PM Wed 33 33 N 8 3392 4500 0 Blue 0
10 PM Wed 33 33 N 7 3392 4500 0 Blue 0
11 PM Wed 33 33 N 7 3392 4500 0 Blue 0
12 Midnight Thu 33 33 N 6 3392 4500 0 Blue 0
1 AM Thu 33 33 N 6 3392 4500 0 Blue 0
2 AM Thu 33 33 N 6 3392 4500 0 Blue 0
3 AM Thu 32 32 NW 5 3392 4500 0 Blue 0
4 AM Thu 31 31 NW 5 3392 4500 0 Blue 0
5 AM Thu 30 30 NW 5 3392 4500 0 Blue 0
6 AM Thu 29 29 N 3 3392 4500 0 Blue 0
7 AM Thu 30 30 N 3 3392 4500 0 Blue 0
8 AM Thu 33 33 N 5 3392 4500 0 Blue 0
9 AM Thu 37 37 N 5 3392 4500 0 Blue 0
10 AM Thu 41 42 N 6 3392 4500 0 Blue 0
11 AM Thu 44 45 N 6 3392 4500 0 Blue 0
12 Noon Thu 46 47 NE 5 3392 4500 0 Blue 0
1 PM Thu 47 48 NE 5 3392 4500 0 Blue 0
2 PM Thu 48 49 E 5 3392 4500 0 Blue 0
3 PM Thu 48 48 SE 6 3392 4500 0 Blue 0
4 PM Thu 46 46 SE 6 3392 4500 0 Blue 0
5 PM Thu 43 43 S 6 3392 4500 0 Blue 0
6 PM Thu 39 39 S 6 3392 4500 0 Blue 0
7 PM Thu 36 36 S 6 3392 4500 0 Blue 0
8 PM Thu 33 33 S 5 3392 4500 0 Blue 0
9 PM Thu 32 32 S 3 3392 4500 0 Blue 0
10 PM Thu 31 31 S 2 3392 4500 0 Blue 0
11 PM Thu 30 30 S 2 3392 4500 0 Blue 0
12 Midnight Fri 30 30 SE 2 3392 4500 0 Blue 0
1 AM Fri 30 30 SE 2 3392 4500 0 Blue 0
2 AM Fri 30 30 SE 2 3392 4500 0 Blue 0
3 AM Fri 29 29 SE 2 3392 4500 0 Blue 0
4 AM Fri 28 28 SE 2 3392 4500 0 Blue 0
5 AM Fri 27 27 SE 2 3392 4500 0 Blue 0
6 AM Fri 26 26 SE 2 3392 4500 0 Blue 0
7 AM Fri 27 27 SE 2 3392 4500 0 Blue 0
8 AM Fri 32 32 SE 3 3392 4500 0 Blue 0
9 AM Fri 38 38 SE 5 3392 4500 0 Blue 0
10 AM Fri 44 45 SE 6 3392 4500 0 Blue 0
11 AM Fri 48 49 SE 6 3392 4500 0 Blue 0
12 Noon Fri 50 51 SE 5 3392 4500 0 Blue 0
1 PM Fri 52 53 SE 5 3392 4500 0 Blue 0
2 PM Fri 53 54 SE 5 3392 4500 0 Blue 0
3 PM Fri 53 53 SE 6 3392 4500 0 Blue 0
4 PM Fri 51 51 SE 6 3392 4500 0 Blue 0
5 PM Fri 47 47 SE 6 3392 4500 0 Blue 0
6 PM Fri 42 42 SE 6 3392 4500 0 Blue 0
7 PM Fri 37 37 E 6 3392 4500 0 Blue 0
8 PM Fri 34 34 E 5 3392 4500 0 Blue 0
9 PM Fri 32 32 NE 5 3392 4500 0 Blue 0
10 PM Fri 31 31 N 3 3392 4500 0 Blue 0
11 PM Fri 31 31 NE 3 3392 4500 0 Blue 0
12 Midnight Sat 31 31 NE 3 3392 4500 0 Blue 0
1 AM Sat 30 30 E 3 3392 4500 0 Blue 0
2 AM Sat 30 30 NE 3 3392 4500 0 Blue 0
3 AM Sat 29 29 N 3 3392 4500 0 Blue 0
4 AM Sat 28 28 NW 3 3392 4500 0 Blue 0
5 AM Sat 27 27 N 3 3392 4500 0 Blue 0
6 AM Sat 26 26 N 2 3392 4500 0 Blue 0
7 AM Sat 28 28 NE 2 3392 4500 0 Blue 0
8 AM Sat 33 33 NE 3 3392 4500 0 Blue 0
9 AM Sat 40 40 N 3 3392 4500 0 Blue 0
10 AM Sat 47 48 N 5 3392 4500 0 Blue 0
11 AM Sat 51 52 N 5 3392 4500 0 Blue 0
12 Noon Sat 53 54 N 5 3392 4500 0 Blue 0
1 PM Sat 54 55 N 5 3392 4500 0 Blue 0
2 PM Sat 56 57 N 5 3392 4500 0 Blue 0
3 PM Sat 56 56 NW 5 3392 4500 0 Blue 0
4 PM Sat 54 54 NW 5 3392 4500 0 Blue 0
5 PM Sat 50 50 NW 5 3392 4500 0 Blue 0
6 PM Sat 44 44 N 6 3392 4500 0 Blue 0
7 PM Sat 38 38 N 6 3392 4500 0 Blue 0
8 PM Sat 34 34 N 5 3392 4500 0 Blue 0
9 PM Sat 32 32 N 5 3392 4500 0 Blue 0
10 PM Sat 31 31 N 3 3392 4500 0 Blue 0
11 PM Sat 31 31 N 3 3392 4500 0 Blue 0
12 Midnight Sun 31 31 N 3 3392 4500 0 Blue 0
1 AM Sun 30 30 N 3 3392 4500 0 Blue 0
2 AM Sun 30 30 N 3 3392 4500 0 Blue 0
3 AM Sun 29 29 N 3 3392 4500 0 Blue 0
4 AM Sun 28 28 N 3 3392 4500 0 Blue 0
5 AM Sun 27 27 N 3 3392 4500 0 Blue 0
6 AM Sun 26 26 N 3 3392 4500 0 Blue 0
7 AM Sun 28 28 N 3 3392 4500 0 Blue 0
8 AM Sun 35 35 NW 3 3392 4500 0 Blue 0
9 AM Sun 43 44 NW 5 3392 4500 0 Blue 0
10 AM Sun 50 51 W 5 3392 4500 0 Blue 0
11 AM Sun 55 57 W 5 3392 4500 0 Blue 0
12 Noon Sun 58 60 NW 5 3392 4500 0 Blue 0
1 PM Sun 59 60 NW 5 3392 4500 0 Blue 0
2 PM Sun 60 61 NW 5 3392 4500 0 Blue 0
3 PM Sun 60 60 NW 5 3392 4500 0 Blue 0
4 PM Sun 57 57 W 5 3392 4500 0 Blue 0
5 PM Sun 52 52 W 5 3392 4500 0 Blue 0
6 PM Sun 46 46 W 6 3392 4500 0 Blue 0
7 PM Sun 40 40 W 6 3392 4500 0 Blue 0
8 PM Sun 37 37 W 6 3392 4500 0 Blue 0
9 PM Sun 35 35 W 6 3392 4500 0 Blue 0
10 PM Sun 34 34 W 6 3392 4500 0 Blue 0
11 PM Sun 33 33 W 6 3392 4500 0 Blue 0
12 Midnight Mon 33 33 W 6 3392 4500 0 Blue 0
1 AM Mon 32 32 W 6 3392 4500 0 Blue 0
2 AM Mon 32 32 W 6 3392 4500 0 Blue 0
3 AM Mon 31 31 W 6 3392 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 ac_soaring@yahoo.com