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

Station:

KFGZ

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)
5 AM Thu 29 29 NW 5 7206 7169 369 Blue 5
6 AM Thu 27 27 W 3 7182 7149 349 Blue 3
7 AM Thu 26 26 SW 3 7169 7149 349 Blue 2
8 AM Thu 28 28 S 3 7194 7157 357 Blue 4
9 AM Thu 33 33 SE 2 7256 7218 418 Blue 9
10 AM Thu 41 42 E 2 7478 7363 563 Blue 17
11 AM Thu 48 50 E 3 8229 7785 985 Blue 25
12 Noon Thu 53 55 E 5 8543 8350 1550 Blue 30
1 PM Thu 55 57 E 5 8949 8475 1675 Blue 32
2 PM Thu 56 58 SE 6 9172 8538 1738 Blue 33
3 PM Thu 56 57 SE 6 8949 8475 1675 Blue 32
4 PM Thu 56 56 SE 7 8726 8413 1613 Blue 31
5 PM Thu 53 53 SE 7 8417 8224 1424 Blue 28
6 PM Thu 48 48 S 6 7883 7599 799 Blue 23
7 PM Thu 42 42 S 6 7478 7363 563 Blue 17
8 PM Thu 37 37 S 7 7305 7268 468 Blue 13
9 PM Thu 35 35 S 7 7280 7243 443 Blue 11
10 PM Thu 35 35 S 7 7280 7243 443 Blue 11
11 PM Thu 35 35 S 7 7280 7243 443 Blue 11
12 Midnight Fri 34 34 SW 7 7268 7231 431 Blue 10
1 AM Fri 33 33 SW 7 7256 7218 418 Blue 9
2 AM Fri 32 32 SW 8 7243 7206 406 Blue 8
3 AM Fri 32 32 SW 8 7243 7206 406 Blue 8
4 AM Fri 32 32 SW 8 7243 7206 406 Blue 8
5 AM Fri 31 31 SW 8 7231 7194 394 Blue 7
6 AM Fri 30 30 SW 9 7219 7181 381 Blue 6
7 AM Fri 29 29 SW 9 7206 7169 369 Blue 5
8 AM Fri 31 31 SW 10 7231 7194 394 Blue 7
9 AM Fri 37 37 SW 10 7305 7268 468 Blue 13
10 AM Fri 45 45 SW 12 7604 7476 676 Blue 20
11 AM Fri 52 53 SW 15 8417 8224 1424 Blue 28
12 Noon Fri 56 57 SW 16 8949 8475 1675 Blue 32
1 PM Fri 58 59 SW 20 9355 8706 1906 Blue 34
2 PM Fri 58 59 SW 23 9355 8706 1906 Blue 34
3 PM Fri 58 58 SW 23 9172 8538 1738 Blue 33
4 PM Fri 56 56 SW 23 8726 8413 1613 Blue 31
5 PM Fri 53 53 SW 23 8417 8224 1424 Blue 28
6 PM Fri 50 50 SW 21 8229 7785 985 Blue 25
7 PM Fri 48 48 SW 21 7883 7599 799 Blue 23
8 PM Fri 45 45 SW 21 7604 7476 676 Blue 20
9 PM Fri 43 43 SW 20 7515 7401 601 Blue 18
10 PM Fri 43 43 SW 20 7515 7401 601 Blue 18
11 PM Fri 43 43 SW 21 7515 7401 601 Blue 18
12 Midnight Sat 42 42 SW 22 7478 7363 563 Blue 17
1 AM Sat 40 40 SW 24 7402 7305 505 Blue 15
2 AM Sat 40 40 SW 26 7402 7305 505 Blue 15
3 AM Sat 39 39 SW 28 7365 7292 492 Blue 14
4 AM Sat 39 39 S 28 7365 7292 492 Blue 14
5 AM Sat 38 38 S 29 7327 7280 480 Blue 13
6 AM Sat 37 37 S 26 7305 7268 468 Blue 13
7 AM Sat 35 35 S 25 7280 7243 443 Blue 11
8 AM Sat 35 35 SW 25 7280 7243 443 Blue 11
9 AM Sat 36 36 SW 25 7293 7255 455 Blue 12
10 AM Sat 37 37 SW 26 7305 7268 468 Blue 13
11 AM Sat 40 40 SW 29 7402 7305 505 Blue 15
12 Noon Sat 40 40 SW 30 7402 7305 505 Blue 15
1 PM Sat 40 41 SW 31 7440 7325 525 Blue 16
2 PM Sat 40 40 SW 32 7402 7305 505 Blue 15
3 PM Sat 38 38 SW 30 7327 7280 480 Blue 13
4 PM Sat 37 37 SW 28 7305 7268 468 Blue 13
5 PM Sat 36 36 SW 25 7293 7255 455 Blue 12
6 PM Sat 33 33 SW 23 7256 7218 418 Blue 9
7 PM Sat 31 31 SW 22 7231 7194 394 Blue 7
8 PM Sat 30 30 W 21 7219 7181 381 Blue 6
9 PM Sat 29 29 W 20 7206 7169 369 Blue 5
10 PM Sat 29 29 W 20 7206 7169 369 Blue 5
11 PM Sat 30 30 W 20 7219 7181 381 Blue 6
12 Midnight Sun 29 29 W 18 7206 7169 369 Blue 5
1 AM Sun 28 28 W 18 7194 7157 357 Blue 4
2 AM Sun 27 27 W 18 7182 7149 349 Blue 3
3 AM Sun 27 27 W 18 7182 7149 349 Blue 3
4 AM Sun 26 26 W 18 7169 7149 349 Blue 2
5 AM Sun 25 25 W 18 7157 7149 349 Blue 1
6 AM Sun 24 24 W 17 0 6800 0 Blue 0
7 AM Sun 23 23 NW 17 0 6800 0 Blue 0
8 AM Sun 24 24 NW 16 0 6800 0 Blue 0
9 AM Sun 27 27 NW 15 7182 7149 349 Blue 3
10 AM Sun 32 33 NW 15 7256 7218 418 Blue 9
11 AM Sun 37 39 NW 15 7365 7292 492 Blue 14
12 Noon Sun 39 41 NW 15 7440 7325 525 Blue 16
1 PM Sun 41 43 NW 15 7515 7401 601 Blue 18
2 PM Sun 42 44 NW 14 7553 7438 638 Blue 19
3 PM Sun 42 43 NW 14 7515 7401 601 Blue 18
4 PM Sun 42 42 NW 13 7478 7363 563 Blue 17
5 PM Sun 41 41 NW 13 7440 7325 525 Blue 16
6 PM Sun 38 38 NW 12 7327 7280 480 Blue 13
7 PM Sun 36 36 NW 10 7293 7255 455 Blue 12
8 PM Sun 33 33 NW 9 7256 7218 418 Blue 9
9 PM Sun 30 30 NW 8 7219 7181 381 Blue 6
10 PM Sun 29 29 NW 7 7206 7169 369 Blue 5
11 PM Sun 28 28 NW 6 7194 7157 357 Blue 4
12 Midnight Mon 27 27 NW 6 7182 7149 349 Blue 3
1 AM Mon 26 26 W 5 7169 7149 349 Blue 2
2 AM Mon 26 26 W 5 7169 7149 349 Blue 2
3 AM Mon 25 25 W 5 7157 7149 349 Blue 1
4 AM Mon 25 25 W 5 7157 7149 349 Blue 1
5 AM Mon 24 24 SW 5 0 6800 0 Blue 0
6 AM Mon 22 22 SW 5 0 6800 0 Blue 0
7 AM Mon 22 22 SW 5 0 6800 0 Blue 0
8 AM Mon 24 24 SW 5 0 6800 0 Blue 0
9 AM Mon 29 29 S 5 7206 7169 369 Blue 5
10 AM Mon 35 36 S 5 7293 7255 455 Blue 12
11 AM Mon 41 42 S 5 7478 7363 563 Blue 17
12 Noon Mon 46 48 SE 5 7883 7599 799 Blue 23
1 PM Mon 48 50 SE 5 8229 7785 985 Blue 25
2 PM Mon 49 50 SE 6 8229 7785 985 Blue 25
3 PM Mon 49 50 E 7 8229 7785 985 Blue 25
4 PM Mon 48 48 E 7 7883 7599 799 Blue 23
5 PM Mon 46 46 E 7 7697 7514 714 Blue 21
6 PM Mon 42 42 E 6 7478 7363 563 Blue 17
7 PM Mon 38 38 E 5 7327 7280 480 Blue 13
8 PM Mon 35 35 E 3 7280 7243 443 Blue 11
9 PM Mon 33 33 SE 2 7256 7218 418 Blue 9
10 PM Mon 31 31 W 2 7231 7194 394 Blue 7
11 PM Mon 30 30 W 3 7219 7181 381 Blue 6
12 Midnight Tue 29 29 W 3 7206 7169 369 Blue 5
1 AM Tue 28 28 NW 3 7194 7157 357 Blue 4
2 AM Tue 27 27 NW 5 7182 7149 349 Blue 3
3 AM Tue 26 26 NW 3 7169 7149 349 Blue 2
4 AM Tue 26 26 NW 5 7169 7149 349 Blue 2
5 AM Tue 26 26 N 6 7169 7149 349 Blue 2
6 AM Tue 25 25 N 6 7157 7149 349 Blue 1
7 AM Tue 25 25 N 7 7157 7149 349 Blue 1
8 AM Tue 27 27 N 7 7182 7149 349 Blue 3
9 AM Tue 32 32 N 7 7243 7206 406 Blue 8
10 AM Tue 37 38 N 7 7327 7280 480 Blue 13
11 AM Tue 43 45 N 8 7604 7476 676 Blue 20
12 Noon Tue 46 48 N 8 7883 7599 799 Blue 23
1 PM Tue 48 50 N 9 8229 7785 985 Blue 25
2 PM Tue 49 51 N 9 8292 7877 1077 Blue 26
3 PM Tue 50 51 N 10 8292 7877 1077 Blue 26
4 PM Tue 50 50 N 10 8229 7785 985 Blue 25
5 PM Tue 49 49 N 10 8054 7692 892 Blue 24
6 PM Tue 46 46 N 9 7697 7514 714 Blue 21
7 PM Tue 43 43 N 8 7515 7401 601 Blue 18
8 PM Tue 39 39 N 8 7365 7292 492 Blue 14
9 PM Tue 37 37 N 7 7305 7268 468 Blue 13
10 PM Tue 35 35 N 7 7280 7243 443 Blue 11
11 PM Tue 34 34 N 6 7268 7231 431 Blue 10
12 Midnight Wed 32 32 N 5 7243 7206 406 Blue 8
1 AM Wed 31 31 NW 5 7231 7194 394 Blue 7
2 AM Wed 29 29 NW 5 7206 7169 369 Blue 5
3 AM Wed 29 29 W 3 7206 7169 369 Blue 5
4 AM Wed 28 28 SW 3 7194 7157 357 Blue 4

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