Detailed Predictions for: Horseshoe
Launch Lat, Long, Altitude (f): 36.472708, -118.115092, 9085
LZ Altitude (f): 3640
Sounding

Station:

KVBG

Date/Time:

17 APR 2021

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 Sat 55 55 WNW 6 7 20955 19152 10067 Blue 16
1 AM Sat 55 55 WNW 6 7 20955 19152 10067 Blue 16
2 AM Sat 55 55 NW 6 8 20955 19152 10067 Blue 16
3 AM Sat 54 54 NW 7 9 20500 18336 9251 Blue 15
4 AM Sat 53 53 NW 8 10 20032 17738 8653 Blue 14
5 AM Sat 52 52 NNW 9 11 19536 17113 8028 Blue 13
6 AM Sat 53 53 NNW 10 11 20032 17738 8653 Blue 14
7 AM Sat 53 53 NNW 10 11 20032 17738 8653 Blue 14
8 AM Sat 54 55 NNW 10 12 20955 19152 10067 Blue 16
9 AM Sat 51 53 SW 9 14 20032 17738 8653 Blue 14
10 AM Sat 49 53 SE 9 15 20032 17738 8653 Blue 14
11 AM Sat 47 53 NNE 8 17 20032 17738 8653 Blue 14
12 Noon Sat 48 55 NNE 8 18 20955 19152 10067 Blue 16
1 PM Sat 49 56 NNE 9 20 21398 19854 10769 Blue 17
2 PM Sat 50 57 NE 10 21 21831 20318 11233 Blue 18
3 PM Sat 51 56 NE 9 20 21398 19854 10769 Blue 17
4 PM Sat 51 54 NE 9 19 20500 18336 9251 Blue 15
5 PM Sat 52 54 NE 8 18 20500 18336 9251 Blue 15
6 PM Sat 51 51 SE 8 19 18524 16456 7371 Blue 12
7 PM Sat 50 50 WSW 9 19 17922 15760 6675 Blue 11
8 PM Sat 50 50 N 9 19 17922 15760 6675 Blue 11
9 PM Sat 46 46 N 9 16 15174 12371 3286 Blue 7
10 PM Sat 42 42 NNW 9 13 11334 10126 1041 Blue 3
11 PM Sat 39 39 NNW 9 10 10132 9164 79 Blue 0
12 Midnight Sun 44 44 SW 8 9 13478 10871 1786 Blue 5
1 AM Sun 50 50 ESE 7 8 17922 15760 6675 Blue 11
2 AM Sun 55 55 N 6 7 20955 19152 10067 Blue 16
3 AM Sun 54 54 ESE 8 9 20500 18336 9251 Blue 15
4 AM Sun 53 53 SW 9 11 20032 17738 8653 Blue 14
5 AM Sun 52 52 NNW 11 13 19536 17113 8028 Blue 13
6 AM Sun 49 49 NNW 11 17 17291 15018 5933 Blue 10
7 AM Sun 47 47 NNW 12 21 15924 13345 4260 Blue 8
8 AM Sun 44 45 NNW 12 26 14364 11247 2162 Blue 6
9 AM Sun 46 48 N 12 25 16627 14219 5134 Blue 9
10 AM Sun 48 52 N 11 24 19536 17113 8028 Blue 13
11 AM Sun 50 56 N 11 23 21398 19854 10769 Blue 17
12 Noon Sun 52 59 WSW 10 21 22668 21210 12125 Blue 20
1 PM Sun 53 60 SE 9 19 23073 21640 12555 Blue 21
2 PM Sun 55 62 N 8 17 23859 22471 13386 Blue 23
3 PM Sun 56 61 ESE 8 16 23470 22060 12975 Blue 22
4 PM Sun 57 60 WSW 7 15 23073 21640 12555 Blue 21
5 PM Sun 57 59 N 6 14 22668 21210 12125 Blue 20
6 PM Sun 56 56 NNW 5 12 21398 19854 10769 Blue 17
7 PM Sun 54 54 NW 4 10 20500 18336 9251 Blue 15
8 PM Sun 53 53 WNW 3 8 20032 17738 8653 Blue 14
9 PM Sun 51 51 WNW 4 8 18524 16456 7371 Blue 12
10 PM Sun 48 48 WNW 5 8 16627 14219 5134 Blue 9
11 PM Sun 46 46 WNW 6 9 15174 12371 3286 Blue 7
12 Midnight Mon 50 50 WNW 7 10 17922 15760 6675 Blue 11
1 AM Mon 55 55 WNW 7 11 20955 19152 10067 Blue 16
2 AM Mon 59 59 WNW 7 12 22668 21210 12125 Blue 20
3 AM Mon 59 59 WNW 8 13 22668 21210 12125 Blue 20
4 AM Mon 58 58 NW 9 15 22254 20770 11685 Blue 19
5 AM Mon 57 57 NW 10 16 21831 20318 11233 Blue 18
6 AM Mon 56 56 NW 9 16 21398 19854 10769 Blue 17
7 AM Mon 55 55 NW 8 16 20955 19152 10067 Blue 16
8 AM Mon 54 55 NW 8 16 20955 19152 10067 Blue 16
9 AM Mon 57 59 SW 7 14 22668 21210 12125 Blue 20
10 AM Mon 59 63 ESE 6 12 24112 22874 13789 Blue 24
11 AM Mon 62 68 N 6 9 25319 24405 15320 White 29
12 Noon Mon 62 69 NNE 5 10 25511 25511 16426 White 30
1 PM Mon 62 69 NE 5 10 25511 25511 16426 White 30
2 PM Mon 62 69 ENE 5 10 25511 25511 16426 White 30
3 PM Mon 63 68 E 4 10 25319 24405 15320 White 29
4 PM Mon 64 67 E 4 10 25128 24170 15085 White 28
5 PM Mon 65 67 ESE 4 9 25128 24170 15085 White 28
6 PM Mon 63 63 SE 4 10 24112 22874 13789 Blue 24
7 PM Mon 62 62 SSE 5 10 23859 22471 13386 Blue 23
8 PM Mon 61 61 SSW 5 11 23470 22060 12975 Blue 22
9 PM Mon 58 58 SSW 4 8 22254 20770 11685 Blue 19
10 PM Mon 56 56 SW 3 6 21398 19854 10769 Blue 17
11 PM Mon 54 54 WSW 2 3 20500 18336 9251 Blue 15

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 ac_soaring@yahoo.com