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

Station:

KOAK

Date/Time:

25 APR 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)
5 AM Thu 63 63 NE 6 1339 2000 0 Blue 2
6 AM Thu 62 62 NE 5 1291 2000 0 Blue 1
7 AM Thu 63 63 NE 5 1339 2000 0 Blue 2
8 AM Thu 70 71 NE 3 1730 2000 0 Blue 10
9 AM Thu 76 78 S 2 2399 2072 72 Blue 17
10 AM Thu 78 82 S 3 2854 2503 503 Blue 21
11 AM Thu 80 86 SW 3 3520 2975 975 Blue 25
12 Noon Thu 82 89 SW 3 7227 3505 1505 Blue 28
1 PM Thu 84 92 SW 5 9545 7043 5043 Blue 31
2 PM Thu 86 93 W 5 10173 7955 5955 Blue 32
3 PM Thu 87 93 W 6 10173 7955 5955 Blue 32
4 PM Thu 88 92 W 6 9545 7043 5043 Blue 31
5 PM Thu 88 90 W 6 8148 4227 2227 Blue 29
6 PM Thu 86 86 W 6 3520 2975 975 Blue 25
7 PM Thu 83 83 NW 5 2982 2603 603 Blue 22
8 PM Thu 76 76 NW 3 2182 2000 0 Blue 15
9 PM Thu 73 73 NW 3 1861 2000 0 Blue 12
10 PM Thu 70 70 NW 5 1682 2000 0 Blue 9
11 PM Thu 68 68 NW 5 1584 2000 0 Blue 7
12 Midnight Fri 67 67 NE 5 1535 2000 0 Blue 6
1 AM Fri 64 64 NE 5 1388 2000 0 Blue 3
2 AM Fri 63 63 NE 5 1339 2000 0 Blue 2
3 AM Fri 62 62 NE 5 1291 2000 0 Blue 1
4 AM Fri 61 61 NE 5 1242 2000 0 Blue 0
5 AM Fri 62 62 NE 5 1291 2000 0 Blue 1
6 AM Fri 61 61 NE 5 1242 2000 0 Blue 0
7 AM Fri 62 62 NE 3 1291 2000 0 Blue 1
8 AM Fri 69 70 E 2 1682 2000 0 Blue 9
9 AM Fri 75 77 SE 2 2290 2000 0 Blue 16
10 AM Fri 77 81 SW 3 2726 2395 395 Blue 20
11 AM Fri 79 85 SW 5 3311 2847 847 Blue 24
12 Noon Fri 81 88 SW 6 5666 3298 1298 Blue 27
1 PM Fri 83 90 W 6 8148 4227 2227 Blue 29
2 PM Fri 85 92 W 6 9545 7043 5043 Blue 31
3 PM Fri 86 91 W 6 8886 5333 3333 Blue 30
4 PM Fri 87 90 W 7 8148 4227 2227 Blue 29
5 PM Fri 87 89 NW 7 7227 3505 1505 Blue 28
6 PM Fri 85 85 NW 6 3311 2847 847 Blue 24
7 PM Fri 82 82 NW 6 2854 2503 503 Blue 21
8 PM Fri 74 74 NW 5 1968 2000 0 Blue 13
9 PM Fri 71 71 NW 5 1730 2000 0 Blue 10
10 PM Fri 69 69 N 5 1633 2000 0 Blue 8
11 PM Fri 67 67 N 5 1535 2000 0 Blue 6
12 Midnight Sat 65 65 N 5 1437 2000 0 Blue 4
1 AM Sat 62 62 NE 5 1291 2000 0 Blue 1
2 AM Sat 61 61 NE 5 1242 2000 0 Blue 0
3 AM Sat 60 60 NE 5 1193 2000 0 Blue 0
4 AM Sat 59 59 NE 5 1144 2000 0 Blue 0
5 AM Sat 60 60 NE 5 1193 2000 0 Blue 0
6 AM Sat 59 59 NE 5 1144 2000 0 Blue 0
7 AM Sat 60 60 NE 3 1193 2000 0 Blue 0
8 AM Sat 67 68 NE 3 1584 2000 0 Blue 7
9 AM Sat 73 75 E 3 2075 2000 0 Blue 14
10 AM Sat 75 79 S 5 2508 2179 179 Blue 18
11 AM Sat 77 82 SW 5 2854 2503 503 Blue 21
12 Noon Sat 79 85 SW 5 3311 2847 847 Blue 24
1 PM Sat 81 86 W 6 3520 2975 975 Blue 25
2 PM Sat 83 87 W 6 4314 3103 1103 Blue 26
3 PM Sat 84 86 W 6 3520 2975 975 Blue 25
4 PM Sat 85 86 W 6 3520 2975 975 Blue 25
5 PM Sat 85 85 W 6 3311 2847 847 Blue 24
6 PM Sat 83 83 W 5 2982 2603 603 Blue 22
7 PM Sat 80 80 NW 5 2607 2286 286 Blue 19
8 PM Sat 73 73 NW 3 1861 2000 0 Blue 12
9 PM Sat 70 70 NW 3 1682 2000 0 Blue 9
10 PM Sat 67 67 NW 3 1535 2000 0 Blue 6
11 PM Sat 65 65 NW 3 1437 2000 0 Blue 4
12 Midnight Sun 64 64 N 3 1388 2000 0 Blue 3
1 AM Sun 61 61 NE 5 1242 2000 0 Blue 0
2 AM Sun 60 60 NE 5 1193 2000 0 Blue 0
3 AM Sun 59 59 NE 5 1144 2000 0 Blue 0
4 AM Sun 58 58 NE 5 1095 2000 0 Blue 0
5 AM Sun 59 59 NE 5 1144 2000 0 Blue 0
6 AM Sun 58 58 NE 5 1095 2000 0 Blue 0
7 AM Sun 59 59 E 3 1144 2000 0 Blue 0
8 AM Sun 65 66 E 3 1486 2000 0 Blue 5
9 AM Sun 71 73 SE 5 1861 2000 0 Blue 12
10 AM Sun 73 77 S 5 2290 2000 0 Blue 16
11 AM Sun 75 79 SW 6 2508 2179 179 Blue 18
12 Noon Sun 77 82 SW 6 2854 2503 503 Blue 21
1 PM Sun 80 86 SW 6 3520 2975 975 Blue 25
2 PM Sun 81 86 SW 6 3520 2975 975 Blue 25
3 PM Sun 82 86 SW 6 3520 2975 975 Blue 25
4 PM Sun 83 86 W 6 3520 2975 975 Blue 25
5 PM Sun 83 84 W 5 3110 2720 720 Blue 23
6 PM Sun 81 81 W 5 2726 2395 395 Blue 20
7 PM Sun 78 78 W 5 2399 2072 72 Blue 17
8 PM Sun 71 71 W 5 1730 2000 0 Blue 10
9 PM Sun 68 68 W 5 1584 2000 0 Blue 7
10 PM Sun 65 65 W 5 1437 2000 0 Blue 4
11 PM Sun 63 63 NW 3 1339 2000 0 Blue 2
12 Midnight Mon 62 62 NW 3 1291 2000 0 Blue 1
1 AM Mon 59 59 NW 3 1144 2000 0 Blue 0
2 AM Mon 58 58 NW 3 1095 2000 0 Blue 0
3 AM Mon 57 57 NW 3 1046 2000 0 Blue 0
4 AM Mon 56 56 NW 3 998 2000 0 Blue 0
5 AM Mon 57 57 W 2 1046 2000 0 Blue 0
6 AM Mon 56 56 W 2 998 2000 0 Blue 0
7 AM Mon 56 56 W 2 998 2000 0 Blue 0
8 AM Mon 62 62 W 2 1291 2000 0 Blue 1
9 AM Mon 66 67 W 2 1535 2000 0 Blue 6
10 AM Mon 68 71 W 2 1730 2000 0 Blue 10
11 AM Mon 70 74 SW 6 1968 2000 0 Blue 13
12 Noon Mon 71 76 SW 6 2182 2000 0 Blue 15
1 PM Mon 73 78 SW 6 2399 2072 72 Blue 17
2 PM Mon 74 79 SW 6 2508 2179 179 Blue 18
3 PM Mon 75 79 SW 6 2508 2179 179 Blue 18
4 PM Mon 76 78 SW 6 2399 2072 72 Blue 17
5 PM Mon 76 77 W 3 2290 2000 0 Blue 16
6 PM Mon 75 75 W 3 2075 2000 0 Blue 14
7 PM Mon 72 72 W 3 1779 2000 0 Blue 11
8 PM Mon 66 66 W 3 1486 2000 0 Blue 5
9 PM Mon 63 63 W 3 1339 2000 0 Blue 2
10 PM Mon 62 62 W 3 1291 2000 0 Blue 1
11 PM Mon 60 60 NW 2 1193 2000 0 Blue 0
12 Midnight Tue 59 59 NW 2 1144 2000 0 Blue 0
1 AM Tue 57 57 NW 2 1046 2000 0 Blue 0
2 AM Tue 56 56 NW 2 998 2000 0 Blue 0
3 AM Tue 55 55 NW 2 949 2000 0 Blue 0
4 AM Tue 54 54 NW 2 909 2000 0 Blue 0
5 AM Tue 55 55 S 5 949 2000 0 Blue 0
6 AM Tue 54 54 S 5 909 2000 0 Blue 0
7 AM Tue 54 54 S 5 909 2000 0 Blue 0
8 AM Tue 60 60 S 5 1193 2000 0 Blue 0
9 AM Tue 64 65 S 5 1437 2000 0 Blue 4
10 AM Tue 66 69 S 5 1633 2000 0 Blue 8
11 AM Tue 68 72 SW 7 1779 2000 0 Blue 11
12 Noon Tue 69 74 SW 7 1968 2000 0 Blue 13
1 PM Tue 71 76 SW 7 2182 2000 0 Blue 15
2 PM Tue 72 76 SW 7 2182 2000 0 Blue 15
3 PM Tue 73 77 SW 7 2290 2000 0 Blue 16
4 PM Tue 74 76 SW 7 2182 2000 0 Blue 15
5 PM Tue 74 75 W 7 2075 2000 0 Blue 14
6 PM Tue 73 73 W 7 1861 2000 0 Blue 12
7 PM Tue 69 69 W 7 1633 2000 0 Blue 8
8 PM Tue 63 63 W 7 1339 2000 0 Blue 2
9 PM Tue 60 60 W 7 1193 2000 0 Blue 0
10 PM Tue 58 58 W 7 1095 2000 0 Blue 0
11 PM Tue 56 56 NW 3 998 2000 0 Blue 0
12 Midnight Wed 55 55 NW 3 949 2000 0 Blue 0
1 AM Wed 53 53 NW 3 909 2000 0 Blue 0
2 AM Wed 52 52 NW 3 909 2000 0 Blue 0
3 AM Wed 51 51 NW 3 909 2000 0 Blue 0
4 AM Wed 50 50 NW 3 909 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