Detailed Predictions for: Dunlap
Launch Altitude (f): 4460
LZ Altitude (f): 1950
Sounding

Station:

KOAK

Date/Time:

18 SEP 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)
5 AM Tue 53 48 N 5 2492 4460 0 Blue 1
6 AM Tue 55 50 N 5 2630 4460 0 Blue 3
7 AM Tue 53 48 N 5 2492 4460 0 Blue 1
8 AM Tue 60 55 E 2 3154 4460 0 Blue 8
9 AM Tue 70 66 E 2 3413 4460 0 Blue 19
10 AM Tue 74 72 E 2 4342 4460 0 Blue 25
11 AM Tue 77 76 SW 6 6312 4615 155 Blue 29
12 Noon Tue 78 79 SW 6 7270 6271 1811 Blue 32
1 PM Tue 81 82 SW 6 7846 7240 2780 Blue 35
2 PM Tue 82 83 SW 7 8141 7431 2971 Blue 36
3 PM Tue 83 82 SW 7 7846 7240 2780 Blue 35
4 PM Tue 83 81 SW 7 7654 6937 2477 Blue 34
5 PM Tue 81 77 W 6 6647 5414 954 Blue 30
6 PM Tue 78 73 W 6 4637 4460 0 Blue 26
7 PM Tue 69 64 W 6 3366 4460 0 Blue 17
8 PM Tue 62 57 NW 6 3201 4460 0 Blue 10
9 PM Tue 60 55 NW 6 3154 4460 0 Blue 8
10 PM Tue 58 53 NW 6 3107 4460 0 Blue 6
11 PM Tue 57 52 NE 3 2913 4460 0 Blue 5
12 Midnight Wed 56 51 NE 3 2693 4460 0 Blue 4
1 AM Wed 58 53 NE 3 3107 4460 0 Blue 6
2 AM Wed 57 52 NE 3 2913 4460 0 Blue 5
3 AM Wed 56 51 NE 3 2693 4460 0 Blue 4
4 AM Wed 55 50 NE 3 2630 4460 0 Blue 3
5 AM Wed 54 49 N 5 2567 4460 0 Blue 2
6 AM Wed 52 47 N 5 2293 4460 0 Blue 0
7 AM Wed 51 46 N 5 2293 4460 0 Blue 0
8 AM Wed 59 54 E 2 3131 4460 0 Blue 7
9 AM Wed 68 64 E 2 3366 4460 0 Blue 17
10 AM Wed 73 71 E 2 4100 4460 0 Blue 24
11 AM Wed 75 75 SW 6 5979 4460 0 Blue 28
12 Noon Wed 77 78 SW 6 6987 5941 1481 Blue 31
1 PM Wed 80 81 SW 6 7654 6937 2477 Blue 34
2 PM Wed 81 82 W 7 7846 7240 2780 Blue 35
3 PM Wed 82 81 W 7 7654 6937 2477 Blue 34
4 PM Wed 82 80 W 7 7462 6601 2141 Blue 33
5 PM Wed 80 76 NW 6 6312 4615 155 Blue 29
6 PM Wed 78 73 NW 6 4637 4460 0 Blue 26
7 PM Wed 70 65 NW 6 3390 4460 0 Blue 18
8 PM Wed 65 60 NW 6 3272 4460 0 Blue 13
9 PM Wed 63 58 NW 6 3225 4460 0 Blue 11
10 PM Wed 61 56 NW 6 3178 4460 0 Blue 9
11 PM Wed 60 55 NE 3 3154 4460 0 Blue 8
12 Midnight Thu 59 54 NE 3 3131 4460 0 Blue 7
1 AM Thu 61 56 NE 3 3178 4460 0 Blue 9
2 AM Thu 60 55 NE 3 3154 4460 0 Blue 8
3 AM Thu 59 54 NE 3 3131 4460 0 Blue 7
4 AM Thu 58 53 NE 3 3107 4460 0 Blue 6
5 AM Thu 57 52 NE 3 2913 4460 0 Blue 5
6 AM Thu 56 51 NE 3 2693 4460 0 Blue 4
7 AM Thu 55 50 NE 3 2630 4460 0 Blue 3
8 AM Thu 63 58 NE 3 3225 4460 0 Blue 11
9 AM Thu 74 70 NE 3 3870 4460 0 Blue 23
10 AM Thu 78 76 NE 3 6312 4615 155 Blue 29
11 AM Thu 81 81 SW 5 7654 6937 2477 Blue 34
12 Noon Thu 83 84 SW 5 8530 7622 3162 Blue 37
1 PM Thu 85 86 SW 5 9293 8068 3608 Blue 39
2 PM Thu 87 88 SW 5 10034 8834 4374 Blue 41
3 PM Thu 88 87 SW 5 9666 8454 3994 Blue 40
4 PM Thu 88 86 SW 5 9293 8068 3608 Blue 39
5 PM Thu 86 82 S 1 7846 7240 2780 Blue 35
6 PM Thu 83 78 S 1 6987 5941 1481 Blue 31
7 PM Thu 75 70 S 1 3870 4460 0 Blue 23
8 PM Thu 69 64 S 1 3366 4460 0 Blue 17
9 PM Thu 67 62 S 1 3319 4460 0 Blue 15
10 PM Thu 65 60 S 1 3272 4460 0 Blue 13
11 PM Thu 65 60 SE 3 3272 4460 0 Blue 13
12 Midnight Fri 64 59 SE 3 3248 4460 0 Blue 12
1 AM Fri 65 60 SE 3 3272 4460 0 Blue 13
2 AM Fri 64 59 SE 3 3248 4460 0 Blue 12
3 AM Fri 64 59 SE 3 3248 4460 0 Blue 12
4 AM Fri 62 57 SE 3 3201 4460 0 Blue 10
5 AM Fri 62 57 NE 5 3201 4460 0 Blue 10
6 AM Fri 60 55 NE 5 3154 4460 0 Blue 8
7 AM Fri 59 54 NE 5 3131 4460 0 Blue 7
8 AM Fri 66 61 NE 5 3295 4460 0 Blue 14
9 AM Fri 75 71 NE 5 4100 4460 0 Blue 24
10 AM Fri 79 77 NE 5 6647 5414 954 Blue 30
11 AM Fri 82 81 SW 5 7654 6937 2477 Blue 34
12 Noon Fri 83 84 SW 5 8530 7622 3162 Blue 37
1 PM Fri 86 87 SW 5 9666 8454 3994 Blue 40
2 PM Fri 87 88 SW 5 10034 8834 4374 Blue 41
3 PM Fri 88 87 SW 5 9666 8454 3994 Blue 40
4 PM Fri 88 86 SW 5 9293 8068 3608 Blue 39
5 PM Fri 86 82 W 5 7846 7240 2780 Blue 35
6 PM Fri 83 78 W 5 6987 5941 1481 Blue 31
7 PM Fri 74 69 W 5 3640 4460 0 Blue 22
8 PM Fri 67 62 W 5 3319 4460 0 Blue 15
9 PM Fri 65 60 W 5 3272 4460 0 Blue 13
10 PM Fri 63 58 W 5 3225 4460 0 Blue 11
11 PM Fri 62 57 SE 5 3201 4460 0 Blue 10
12 Midnight Sat 61 56 SE 5 3178 4460 0 Blue 9
1 AM Sat 63 58 SE 5 3225 4460 0 Blue 11
2 AM Sat 62 57 SE 5 3201 4460 0 Blue 10
3 AM Sat 61 56 SE 5 3178 4460 0 Blue 9
4 AM Sat 60 55 SE 5 3154 4460 0 Blue 8
5 AM Sat 59 54 NE 5 3131 4460 0 Blue 7
6 AM Sat 57 52 NE 5 2913 4460 0 Blue 5
7 AM Sat 56 51 NE 5 2693 4460 0 Blue 4
8 AM Sat 64 59 NE 5 3248 4460 0 Blue 12
9 AM Sat 73 69 NE 5 3640 4460 0 Blue 22
10 AM Sat 78 76 NE 5 6312 4615 155 Blue 29
11 AM Sat 80 79 SW 5 7270 6271 1811 Blue 32
12 Noon Sat 82 83 SW 5 8141 7431 2971 Blue 36
1 PM Sat 85 86 SW 5 9293 8068 3608 Blue 39
2 PM Sat 86 87 SW 5 9666 8454 3994 Blue 40
3 PM Sat 87 86 SW 5 9293 8068 3608 Blue 39
4 PM Sat 87 85 SW 5 8914 7812 3352 Blue 38
5 PM Sat 85 81 W 6 7654 6937 2477 Blue 34
6 PM Sat 82 77 W 6 6647 5414 954 Blue 30
7 PM Sat 73 68 W 6 3499 4460 0 Blue 21
8 PM Sat 66 61 W 6 3295 4460 0 Blue 14
9 PM Sat 64 59 W 6 3248 4460 0 Blue 12
10 PM Sat 62 57 W 6 3201 4460 0 Blue 10
11 PM Sat 61 56 SE 5 3178 4460 0 Blue 9
12 Midnight Sun 60 55 SE 5 3154 4460 0 Blue 8
1 AM Sun 62 57 SE 5 3201 4460 0 Blue 10
2 AM Sun 61 56 SE 5 3178 4460 0 Blue 9
3 AM Sun 60 55 SE 5 3154 4460 0 Blue 8
4 AM Sun 59 54 SE 5 3131 4460 0 Blue 7
5 AM Sun 58 53 NE 5 3107 4460 0 Blue 6
6 AM Sun 56 51 NE 5 2693 4460 0 Blue 4
7 AM Sun 55 50 NE 5 2630 4460 0 Blue 3
8 AM Sun 62 57 NE 5 3201 4460 0 Blue 10
9 AM Sun 72 68 NE 5 3499 4460 0 Blue 21
10 AM Sun 76 74 NE 5 5481 4460 0 Blue 27
11 AM Sun 79 78 SW 5 6987 5941 1481 Blue 31
12 Noon Sun 80 81 SW 5 7654 6937 2477 Blue 34
1 PM Sun 83 84 SW 5 8530 7622 3162 Blue 37
2 PM Sun 84 85 SW 5 8914 7812 3352 Blue 38
3 PM Sun 85 84 SW 5 8530 7622 3162 Blue 37
4 PM Sun 85 83 SW 5 8141 7431 2971 Blue 36
5 PM Sun 83 79 W 6 7270 6271 1811 Blue 32
6 PM Sun 81 76 W 6 6312 4615 155 Blue 29
7 PM Sun 73 68 W 6 3499 4460 0 Blue 21
8 PM Sun 67 62 W 6 3319 4460 0 Blue 15
9 PM Sun 65 60 W 6 3272 4460 0 Blue 13
10 PM Sun 63 58 W 6 3225 4460 0 Blue 11
11 PM Sun 62 57 SE 5 3201 4460 0 Blue 10
12 Midnight Mon 62 57 SE 5 3201 4460 0 Blue 10
1 AM Mon 63 58 SE 5 3225 4460 0 Blue 11
2 AM Mon 62 57 SE 5 3201 4460 0 Blue 10
3 AM Mon 62 57 SE 5 3201 4460 0 Blue 10
4 AM Mon 60 55 SE 5 3154 4460 0 Blue 8

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