Detailed Predictions for: Lake McClure
Launch Altitude (f): 2000
LZ Altitude (f): 500
Sounding

Station:

KOAK

Date/Time:

18 JAN 2018

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 Thu 48 48 NE 5 1125 2000 0 Blue 0
5 AM Thu 47 47 NE 5 1125 2000 0 Blue 0
6 AM Thu 47 47 NE 5 1125 2000 0 Blue 0
7 AM Thu 48 48 E 3 1125 2000 0 Blue 0
8 AM Thu 50 50 E 3 1125 2000 0 Blue 0
9 AM Thu 54 54 E 3 1125 2000 0 Blue 0
10 AM Thu 58 58 S 5 2638 2000 0 Blue 2
11 AM Thu 60 60 S 5 2864 2560 560 Blue 4
12 Noon Thu 62 63 S 5 3488 2846 846 Blue 7
1 PM Thu 63 63 SW 5 3488 2846 846 Blue 7
2 PM Thu 63 63 SW 5 3488 2846 846 Blue 7
3 PM Thu 63 63 SW 5 3488 2846 846 Blue 7
4 PM Thu 61 61 W 2 3183 2634 634 Blue 5
5 PM Thu 59 59 W 2 2712 2425 425 Blue 3
6 PM Thu 55 55 W 2 1701 2000 0 Blue 0
7 PM Thu 52 52 W 6 1125 2000 0 Blue 0
8 PM Thu 50 50 W 6 1125 2000 0 Blue 0
9 PM Thu 49 49 W 6 1125 2000 0 Blue 0
10 PM Thu 48 48 NW 6 1125 2000 0 Blue 0
11 PM Thu 48 48 NW 6 1125 2000 0 Blue 0
12 Midnight Fri 47 47 NW 6 1125 2000 0 Blue 0
1 AM Fri 46 46 NW 6 1125 2000 0 Blue 0
2 AM Fri 45 45 NW 6 1125 2000 0 Blue 0
3 AM Fri 45 45 NW 6 1125 2000 0 Blue 0
4 AM Fri 45 45 NW 7 1125 2000 0 Blue 0
5 AM Fri 44 44 NW 7 1125 2000 0 Blue 0
6 AM Fri 43 43 NW 7 1125 2000 0 Blue 0
7 AM Fri 42 42 NW 7 1125 2000 0 Blue 0
8 AM Fri 42 42 NW 7 1125 2000 0 Blue 0
9 AM Fri 43 43 NW 7 1125 2000 0 Blue 0
10 AM Fri 46 46 NW 8 1125 2000 0 Blue 0
11 AM Fri 49 50 NW 8 1125 2000 0 Blue 0
12 Noon Fri 51 52 NW 8 1125 2000 0 Blue 0
1 PM Fri 53 54 NW 9 1125 2000 0 Blue 0
2 PM Fri 54 54 NW 9 1125 2000 0 Blue 0
3 PM Fri 54 54 NW 9 1125 2000 0 Blue 0
4 PM Fri 53 53 NW 8 1125 2000 0 Blue 0
5 PM Fri 51 51 NW 8 1125 2000 0 Blue 0
6 PM Fri 49 49 NW 8 1125 2000 0 Blue 0
7 PM Fri 47 47 NW 8 1125 2000 0 Blue 0
8 PM Fri 45 45 NW 8 1125 2000 0 Blue 0
9 PM Fri 43 43 NW 8 1125 2000 0 Blue 0
10 PM Fri 42 42 N 6 1125 2000 0 Blue 0
11 PM Fri 41 41 N 6 1125 2000 0 Blue 0
12 Midnight Sat 40 40 N 6 1125 2000 0 Blue 0
1 AM Sat 39 39 N 6 1125 2000 0 Blue 0
2 AM Sat 39 39 N 6 1125 2000 0 Blue 0
3 AM Sat 38 38 N 6 1125 2000 0 Blue 0
4 AM Sat 37 37 N 5 1125 2000 0 Blue 0
5 AM Sat 36 36 N 5 1125 2000 0 Blue 0
6 AM Sat 35 35 N 5 1125 2000 0 Blue 0
7 AM Sat 36 36 N 5 1125 2000 0 Blue 0
8 AM Sat 38 38 N 5 1125 2000 0 Blue 0
9 AM Sat 42 42 N 5 1125 2000 0 Blue 0
10 AM Sat 46 47 W 8 1125 2000 0 Blue 0
11 AM Sat 48 49 W 8 1125 2000 0 Blue 0
12 Noon Sat 49 51 W 8 1125 2000 0 Blue 0
1 PM Sat 50 51 W 8 1125 2000 0 Blue 0
2 PM Sat 51 52 W 8 1125 2000 0 Blue 0
3 PM Sat 51 51 W 8 1125 2000 0 Blue 0
4 PM Sat 50 50 NW 8 1125 2000 0 Blue 0
5 PM Sat 48 48 NW 8 1125 2000 0 Blue 0
6 PM Sat 45 45 NW 8 1125 2000 0 Blue 0
7 PM Sat 42 42 NW 8 1125 2000 0 Blue 0
8 PM Sat 40 40 NW 8 1125 2000 0 Blue 0
9 PM Sat 40 40 NW 8 1125 2000 0 Blue 0
10 PM Sat 40 40 NE 3 1125 2000 0 Blue 0
11 PM Sat 39 39 NE 3 1125 2000 0 Blue 0
12 Midnight Sun 38 38 NE 3 1125 2000 0 Blue 0
1 AM Sun 37 37 NE 3 1125 2000 0 Blue 0
2 AM Sun 37 37 NE 3 1125 2000 0 Blue 0
3 AM Sun 36 36 NE 3 1125 2000 0 Blue 0
4 AM Sun 36 36 E 5 1125 2000 0 Blue 0
5 AM Sun 35 35 E 5 1125 2000 0 Blue 0
6 AM Sun 35 35 E 5 1125 2000 0 Blue 0
7 AM Sun 36 36 E 5 1125 2000 0 Blue 0
8 AM Sun 39 39 E 5 1125 2000 0 Blue 0
9 AM Sun 43 43 E 5 1125 2000 0 Blue 0
10 AM Sun 47 47 S 5 1125 2000 0 Blue 0
11 AM Sun 50 51 S 5 1125 2000 0 Blue 0
12 Noon Sun 52 53 S 5 1125 2000 0 Blue 0
1 PM Sun 54 55 S 5 1701 2000 0 Blue 0
2 PM Sun 54 54 S 5 1125 2000 0 Blue 0
3 PM Sun 53 53 S 5 1125 2000 0 Blue 0
4 PM Sun 52 52 N 2 1125 2000 0 Blue 0
5 PM Sun 49 49 N 2 1125 2000 0 Blue 0
6 PM Sun 46 46 N 2 1125 2000 0 Blue 0
7 PM Sun 43 43 N 2 1125 2000 0 Blue 0
8 PM Sun 43 43 N 2 1125 2000 0 Blue 0
9 PM Sun 43 43 N 2 1125 2000 0 Blue 0
10 PM Sun 43 43 E 3 1125 2000 0 Blue 0
11 PM Sun 43 43 E 3 1125 2000 0 Blue 0
12 Midnight Mon 43 43 E 3 1125 2000 0 Blue 0
1 AM Mon 42 42 E 3 1125 2000 0 Blue 0
2 AM Mon 41 41 E 3 1125 2000 0 Blue 0
3 AM Mon 41 41 E 3 1125 2000 0 Blue 0
4 AM Mon 40 40 SE 6 1125 2000 0 Blue 0
5 AM Mon 40 40 SE 6 1125 2000 0 Blue 0
6 AM Mon 40 40 SE 6 1125 2000 0 Blue 0
7 AM Mon 41 41 SE 6 1125 2000 0 Blue 0
8 AM Mon 43 43 SE 6 1125 2000 0 Blue 0
9 AM Mon 46 46 SE 6 1125 2000 0 Blue 0
10 AM Mon 48 48 SE 5 1125 2000 0 Blue 0
11 AM Mon 50 50 SE 5 1125 2000 0 Blue 0
12 Noon Mon 52 52 SE 5 1125 2000 0 Blue 0
1 PM Mon 54 54 SE 5 1125 2000 0 Blue 0
2 PM Mon 55 55 SE 5 1701 2000 0 Blue 0
3 PM Mon 55 55 SE 5 1701 2000 0 Blue 0
4 PM Mon 54 54 N 2 1125 2000 0 Blue 0
5 PM Mon 52 52 N 2 1125 2000 0 Blue 0
6 PM Mon 49 49 N 2 1125 2000 0 Blue 0
7 PM Mon 46 46 N 2 1125 2000 0 Blue 0
8 PM Mon 45 45 N 2 1125 2000 0 Blue 0
9 PM Mon 44 44 N 2 1125 2000 0 Blue 0
10 PM Mon 44 44 E 3 1125 2000 0 Blue 0
11 PM Mon 44 44 E 3 1125 2000 0 Blue 0
12 Midnight Tue 43 43 E 3 1125 2000 0 Blue 0
1 AM Tue 43 43 E 3 1125 2000 0 Blue 0
2 AM Tue 42 42 E 3 1125 2000 0 Blue 0
3 AM Tue 42 42 E 3 1125 2000 0 Blue 0
4 AM Tue 41 41 E 5 1125 2000 0 Blue 0
5 AM Tue 40 40 E 5 1125 2000 0 Blue 0
6 AM Tue 39 39 E 5 1125 2000 0 Blue 0
7 AM Tue 40 40 E 5 1125 2000 0 Blue 0
8 AM Tue 42 42 E 5 1125 2000 0 Blue 0
9 AM Tue 46 46 E 5 1125 2000 0 Blue 0
10 AM Tue 49 49 W 2 1125 2000 0 Blue 0
11 AM Tue 52 53 W 2 1125 2000 0 Blue 0
12 Noon Tue 54 55 W 2 1701 2000 0 Blue 0
1 PM Tue 55 56 W 2 2454 2000 0 Blue 0
2 PM Tue 56 56 W 2 2454 2000 0 Blue 0
3 PM Tue 57 57 W 2 2563 2000 0 Blue 1
4 PM Tue 56 56 NW 2 2454 2000 0 Blue 0
5 PM Tue 55 55 NW 2 1701 2000 0 Blue 0
6 PM Tue 52 52 NW 2 1125 2000 0 Blue 0
7 PM Tue 50 50 NW 2 1125 2000 0 Blue 0
8 PM Tue 48 48 NW 2 1125 2000 0 Blue 0
9 PM Tue 47 47 NW 2 1125 2000 0 Blue 0
10 PM Tue 46 46 E 5 1125 2000 0 Blue 0
11 PM Tue 46 46 E 5 1125 2000 0 Blue 0
12 Midnight Wed 45 45 E 5 1125 2000 0 Blue 0
1 AM Wed 45 45 E 5 1125 2000 0 Blue 0
2 AM Wed 45 45 E 5 1125 2000 0 Blue 0
3 AM Wed 44 44 E 5 1125 2000 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