Detailed Predictions for: Merriam Crater
Launch Altitude (f): 6800
LZ Altitude (f): 6000
Sounding

Station:

KFGZ

Date/Time:

26 APR 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)
6 AM Thu 48 48 N 3 7274 7242 442 Blue 12
7 AM Thu 48 48 N 3 7274 7242 442 Blue 12
8 AM Thu 55 57 N 5 7368 7336 536 Blue 20
9 AM Thu 60 64 N 6 7484 7428 628 Blue 27
10 AM Thu 66 71 N 6 12654 8213 1413 Blue 34
11 AM Thu 70 77 NE 7 18051 14726 7926 Blue 40
12 Noon Thu 74 81 NE 7 20059 18187 11387 Blue 44
1 PM Thu 77 84 NE 8 23287 19457 12657 Blue 47
2 PM Thu 79 85 NE 9 23446 20615 13815 Blue 48
3 PM Thu 80 84 NE 10 23287 19457 12657 Blue 47
4 PM Thu 80 82 NE 10 21328 18417 11617 Blue 45
5 PM Thu 80 81 N 10 20059 18187 11387 Blue 44
6 PM Thu 78 78 N 9 18283 15184 8384 Blue 41
7 PM Thu 77 77 N 8 18051 14726 7926 Blue 40
8 PM Thu 72 72 N 7 13799 9096 2296 Blue 35
9 PM Thu 67 67 N 6 8028 7484 684 Blue 30
10 PM Thu 64 64 N 5 7484 7428 628 Blue 27
11 PM Thu 61 61 NE 6 7429 7378 578 Blue 24
12 Midnight Fri 60 60 E 6 7411 7368 568 Blue 23
1 AM Fri 58 58 E 6 7379 7347 547 Blue 21
2 AM Fri 56 56 E 6 7358 7326 526 Blue 19
3 AM Fri 56 56 SE 7 7358 7326 526 Blue 19
4 AM Fri 53 53 SE 7 7326 7294 494 Blue 16
5 AM Fri 52 52 SE 6 7316 7284 484 Blue 15
6 AM Fri 50 50 SE 6 7295 7263 463 Blue 13
7 AM Fri 50 50 SE 7 7295 7263 463 Blue 13
8 AM Fri 56 56 SE 7 7358 7326 526 Blue 19
9 AM Fri 61 62 SE 8 7448 7391 591 Blue 25
10 AM Fri 65 67 SE 7 8028 7484 684 Blue 30
11 AM Fri 69 72 S 6 13799 9096 2296 Blue 35
12 Noon Fri 72 75 S 5 16987 13581 6781 Blue 38
1 PM Fri 74 77 S 5 18051 14726 7926 Blue 40
2 PM Fri 76 78 S 6 18283 15184 8384 Blue 41
3 PM Fri 77 79 S 7 18515 17264 10464 Blue 42
4 PM Fri 77 78 S 9 18283 15184 8384 Blue 41
5 PM Fri 77 77 SW 12 18051 14726 7926 Blue 40
6 PM Fri 76 76 SW 14 17818 14257 7457 Blue 39
7 PM Fri 74 74 SW 14 14862 12346 5546 Blue 37
8 PM Fri 70 70 SW 13 10913 8015 1215 Blue 33
9 PM Fri 66 66 SW 12 7828 7465 665 Blue 29
10 PM Fri 64 64 SW 10 7484 7428 628 Blue 27
11 PM Fri 62 62 SW 8 7448 7391 591 Blue 25
12 Midnight Sat 60 60 SW 7 7411 7368 568 Blue 23
1 AM Sat 59 59 SW 6 7392 7357 557 Blue 22
2 AM Sat 57 57 SW 6 7368 7336 536 Blue 20
3 AM Sat 57 57 S 6 7368 7336 536 Blue 20
4 AM Sat 55 55 S 6 7347 7315 515 Blue 18
5 AM Sat 54 54 S 6 7337 7305 505 Blue 17
6 AM Sat 52 52 S 7 7316 7284 484 Blue 15
7 AM Sat 52 52 S 8 7316 7284 484 Blue 15
8 AM Sat 57 58 S 10 7379 7347 547 Blue 21
9 AM Sat 62 65 S 13 7629 7447 647 Blue 28
10 AM Sat 66 70 S 15 10913 8015 1215 Blue 33
11 AM Sat 70 75 S 18 16987 13581 6781 Blue 38
12 Noon Sat 72 78 S 21 18283 15184 8384 Blue 41
1 PM Sat 75 81 S 23 20059 18187 11387 Blue 44
2 PM Sat 76 81 S 24 20059 18187 11387 Blue 44
3 PM Sat 77 81 SW 26 20059 18187 11387 Blue 44
4 PM Sat 77 79 SW 28 18515 17264 10464 Blue 42
5 PM Sat 77 78 SW 29 18283 15184 8384 Blue 41
6 PM Sat 76 76 SW 30 17818 14257 7457 Blue 39
7 PM Sat 74 74 SW 29 14862 12346 5546 Blue 37
8 PM Sat 69 69 SW 28 9250 7817 1017 Blue 32
9 PM Sat 64 64 SW 26 7484 7428 628 Blue 27
10 PM Sat 61 61 SW 24 7429 7378 578 Blue 24
11 PM Sat 59 59 SW 23 7392 7357 557 Blue 22
12 Midnight Sun 57 57 SW 22 7368 7336 536 Blue 20
1 AM Sun 56 56 SW 21 7358 7326 526 Blue 19
2 AM Sun 54 54 S 21 7337 7305 505 Blue 17
3 AM Sun 53 53 S 20 7326 7294 494 Blue 16
4 AM Sun 51 51 S 20 7305 7273 473 Blue 14
5 AM Sun 50 50 S 20 7295 7263 463 Blue 13
6 AM Sun 48 48 S 21 7274 7242 442 Blue 12
7 AM Sun 47 47 S 21 7263 7231 431 Blue 11
8 AM Sun 53 55 S 21 7347 7315 515 Blue 18
9 AM Sun 57 60 S 22 7411 7368 568 Blue 23
10 AM Sun 62 67 SW 22 8028 7484 684 Blue 30
11 AM Sun 65 72 SW 23 13799 9096 2296 Blue 35
12 Noon Sun 68 75 SW 23 16987 13581 6781 Blue 38
1 PM Sun 70 77 SW 24 18051 14726 7926 Blue 40
2 PM Sun 72 78 SW 25 18283 15184 8384 Blue 41
3 PM Sun 73 77 SW 25 18051 14726 7926 Blue 40
4 PM Sun 73 75 SW 26 16987 13581 6781 Blue 38
5 PM Sun 72 73 SW 26 14388 10578 3778 Blue 36
6 PM Sun 71 71 SW 28 12654 8213 1413 Blue 34
7 PM Sun 70 70 SW 25 10913 8015 1215 Blue 33
8 PM Sun 65 65 SW 23 7629 7447 647 Blue 28
9 PM Sun 60 60 SW 22 7411 7368 568 Blue 23
10 PM Sun 58 58 SW 20 7379 7347 547 Blue 21
11 PM Sun 56 56 SW 17 7358 7326 526 Blue 19
12 Midnight Mon 54 54 SW 15 7337 7305 505 Blue 17
1 AM Mon 53 53 SW 16 7326 7294 494 Blue 16
2 AM Mon 51 51 SW 16 7305 7273 473 Blue 14
3 AM Mon 50 50 SW 17 7295 7263 463 Blue 13
4 AM Mon 48 48 SW 17 7274 7242 442 Blue 12
5 AM Mon 47 47 SW 18 7263 7231 431 Blue 11
6 AM Mon 45 45 SW 18 7242 7211 411 Blue 9
7 AM Mon 47 47 SW 18 7263 7231 431 Blue 11
8 AM Mon 50 51 SW 20 7305 7273 473 Blue 14
9 AM Mon 53 56 SW 20 7358 7326 526 Blue 19
10 AM Mon 57 61 SW 21 7429 7378 578 Blue 24
11 AM Mon 60 65 SW 21 7629 7447 647 Blue 28
12 Noon Mon 62 67 SW 22 8028 7484 684 Blue 30
1 PM Mon 64 69 SW 23 9250 7817 1017 Blue 32
2 PM Mon 66 70 SW 25 10913 8015 1215 Blue 33
3 PM Mon 67 70 SW 26 10913 8015 1215 Blue 33
4 PM Mon 67 69 SW 28 9250 7817 1017 Blue 32
5 PM Mon 66 66 SW 28 7828 7465 665 Blue 29
6 PM Mon 65 65 SW 28 7629 7447 647 Blue 28
7 PM Mon 62 62 SW 25 7448 7391 591 Blue 25
8 PM Mon 59 59 SW 23 7392 7357 557 Blue 22
9 PM Mon 57 57 SW 20 7368 7336 536 Blue 20
10 PM Mon 54 54 SW 16 7337 7305 505 Blue 17
11 PM Mon 52 52 SW 14 7316 7284 484 Blue 15
12 Midnight Tue 50 50 SW 12 7295 7263 463 Blue 13
1 AM Tue 49 49 SW 12 7284 7252 452 Blue 12
2 AM Tue 48 48 SW 13 7274 7242 442 Blue 12
3 AM Tue 46 46 SW 14 7253 7221 421 Blue 10
4 AM Tue 44 44 SW 16 7232 7202 402 Blue 8
5 AM Tue 43 43 SW 17 7221 7194 394 Blue 7
6 AM Tue 43 43 SW 18 7221 7194 394 Blue 7
7 AM Tue 45 45 SW 18 7242 7211 411 Blue 9
8 AM Tue 49 50 SW 18 7295 7263 463 Blue 13
9 AM Tue 52 54 SW 17 7337 7305 505 Blue 17
10 AM Tue 55 58 SW 16 7379 7347 547 Blue 21
11 AM Tue 57 60 SW 16 7411 7368 568 Blue 23
12 Noon Tue 59 62 SW 15 7448 7391 591 Blue 25
1 PM Tue 60 63 SW 15 7466 7410 610 Blue 26
2 PM Tue 62 65 SW 15 7629 7447 647 Blue 28
3 PM Tue 63 65 SW 15 7629 7447 647 Blue 28
4 PM Tue 63 64 SW 14 7484 7428 628 Blue 27
5 PM Tue 62 62 SW 14 7448 7391 591 Blue 25
6 PM Tue 61 61 W 14 7429 7378 578 Blue 24
7 PM Tue 59 59 W 14 7392 7357 557 Blue 22
8 PM Tue 56 56 W 13 7358 7326 526 Blue 19
9 PM Tue 53 53 W 13 7326 7294 494 Blue 16
10 PM Tue 50 50 W 12 7295 7263 463 Blue 13
11 PM Tue 48 48 SW 10 7274 7242 442 Blue 12
12 Midnight Wed 46 46 SW 10 7253 7221 421 Blue 10
1 AM Wed 45 45 SW 10 7242 7211 411 Blue 9
2 AM Wed 44 44 SW 9 7232 7202 402 Blue 8
3 AM Wed 43 43 SW 9 7221 7194 394 Blue 7
4 AM Wed 42 42 SW 9 7211 7185 385 Blue 6
5 AM Wed 41 41 SW 9 7203 7173 373 Blue 5

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