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CastCheck methodology v0.2 · data through 2026-08-30

Los Angeles Intl · NCEP GFS · lead day 6

KLAX · gfs · lead 6

Target day = initialization date + 6 days. This page is a permanent link: the numbers change as history accumulates, the address and the methodology version do not.

Scores use the latest model version segment, gfs-0p25, starting 2026-08-01 — days before that ran a different version of the model and are excluded rather than silently pooled. Of the scored days, 2 carry a QC flag on the observation.

JSON for this page CSV of the daily errors Cite this page

Every number for this combination

All four windows × both initializations × both interpolations × both variables. Errors are computed in °C and shown in °F; CI is a 95 % moving-block bootstrap interval. MAE debiased and skill, debiased remove the constant offset of the window first, so a station that the model always reads a degree too warm is not scored as if it had no skill — compare the two skill columns to see how much of the error is a fixed offset. n QC next to n counts days whose observation carries a QC flag.

VariableInitMethod Windown MAE °F MAE debiased Bias °F RMSE °F ±1 °F±2 °F±3 °F Skill Skill, debiased Period
tmax00Zbilinear30d24 2 QC1.86 [1.23, 2.65]1.78-0.81 [-2.19, 0.26]2.51 [1.56, 3.39]33% [10%, 57%]62%83%+0.40+0.372026-08-07 → 2026-08-30
tmax00Zbilinear90d24 2 QC1.86 [1.18, 2.76]1.78-0.81 [-2.35, 0.38]2.51 [1.52, 3.46]33% [6%, 57%]62%83%+0.40+0.372026-08-07 → 2026-08-30
tmax00Zbilinear365d24 2 QC1.86 [1.16, 2.80]1.78-0.81 [-2.53, 0.41]2.51 [1.45, 3.53]33% [5%, 60%]62%83%+0.40+0.372026-08-07 → 2026-08-30
tmax00Zbilinearall24 2 QC1.86 [1.16, 2.78]1.78-0.81 [-2.38, 0.35]2.51 [1.49, 3.52]33% [0%, 59%]62%83%+0.40+0.372026-08-07 → 2026-08-30
tmax00Znearest30d24 2 QC2.22 [1.55, 3.13]1.84-1.36 [-2.80, -0.08]2.94 [1.88, 4.08]29% [16%, 43%]67%71%+0.28+0.352026-08-07 → 2026-08-30
tmax00Znearest90d24 2 QC2.22 [1.48, 3.20]1.84-1.36 [-2.99, 0.10]2.94 [1.82, 4.19]29% [14%, 44%]67%71%+0.28+0.352026-08-07 → 2026-08-30
tmax00Znearest365d24 2 QC2.22 [1.47, 3.29]1.84-1.36 [-3.18, 0.19]2.94 [1.78, 4.24]29% [13%, 47%]67%71%+0.28+0.352026-08-07 → 2026-08-30
tmax00Znearestall24 2 QC2.22 [1.49, 3.19]1.84-1.36 [-2.97, -0.00]2.94 [1.83, 4.19]29% [14%, 45%]67%71%+0.28+0.352026-08-07 → 2026-08-30
tmax12Zbilinear30d24 2 QC1.80 [1.07, 2.44]1.67-0.87 [-2.09, 0.10]2.40 [1.55, 3.15]38% [24%, 55%]62%79%+0.42+0.412026-08-07 → 2026-08-30
tmax12Zbilinear90d24 2 QC1.80 [0.82, 2.50]1.67-0.87 [-2.25, 0.22]2.40 [1.19, 3.22]38% [25%, 60%]62%79%+0.42+0.412026-08-07 → 2026-08-30
tmax12Zbilinear365d24 2 QC1.80 [0.91, 2.58]1.67-0.87 [-2.51, 0.28]2.40 [1.20, 3.29]38% [25%, 57%]62%79%+0.42+0.412026-08-07 → 2026-08-30
tmax12Zbilinearall24 2 QC1.80 [0.89, 2.56]1.67-0.87 [-2.42, 0.18]2.40 [1.27, 3.23]38% [22%, 57%]62%79%+0.42+0.412026-08-07 → 2026-08-30
tmax12Znearest30d24 2 QC2.10 [1.28, 2.70]1.92-1.16 [-2.24, -0.19]2.74 [1.82, 3.43]38% [21%, 55%]50%67%+0.32+0.322026-08-07 → 2026-08-30
tmax12Znearest90d24 2 QC2.10 [0.94, 2.78]1.92-1.16 [-2.38, -0.04]2.74 [1.37, 3.46]38% [21%, 57%]50%67%+0.32+0.322026-08-07 → 2026-08-30
tmax12Znearest365d24 2 QC2.10 [1.07, 2.78]1.92-1.16 [-2.51, 0.03]2.74 [1.51, 3.49]38% [19%, 56%]50%67%+0.32+0.322026-08-07 → 2026-08-30
tmax12Znearestall24 2 QC2.10 [1.10, 2.81]1.92-1.16 [-2.48, -0.12]2.74 [1.55, 3.49]38% [20%, 57%]50%67%+0.32+0.322026-08-07 → 2026-08-30
tmin00Zbilinear30d24 2 QC3.42 [2.64, 4.34]1.21+3.42 [2.64, 4.34]3.74 [2.86, 4.58]4% [0%, 12%]17%42%-0.64+0.342026-08-07 → 2026-08-30
tmin00Zbilinear90d24 2 QC3.42 [2.59, 4.44]1.21+3.42 [2.59, 4.44]3.74 [2.81, 4.67]4% [0%, 13%]17%42%-0.64+0.342026-08-07 → 2026-08-30
tmin00Zbilinear365d24 2 QC3.42 [2.55, 4.57]1.21+3.42 [2.55, 4.57]3.74 [2.76, 4.83]4% [0%, 14%]17%42%-0.64+0.342026-08-07 → 2026-08-30
tmin00Zbilinearall24 2 QC3.42 [2.49, 4.52]1.21+3.42 [2.49, 4.52]3.74 [2.70, 4.74]4% [0%, 14%]17%42%-0.64+0.342026-08-07 → 2026-08-30
tmin00Znearest30d24 2 QC2.14 [1.42, 2.93]1.34+1.82 [0.89, 2.81]2.51 [1.61, 3.27]21% [7%, 40%]50%79%-0.03+0.272026-08-07 → 2026-08-30
tmin00Znearest90d24 2 QC2.14 [1.29, 3.00]1.34+1.82 [0.81, 2.94]2.51 [1.48, 3.33]21% [5%, 46%]50%79%-0.03+0.272026-08-07 → 2026-08-30
tmin00Znearest365d24 2 QC2.14 [1.32, 3.19]1.34+1.82 [0.73, 3.07]2.51 [1.49, 3.50]21% [0%, 44%]50%79%-0.03+0.272026-08-07 → 2026-08-30
tmin00Znearestall24 2 QC2.14 [1.29, 3.10]1.34+1.82 [0.75, 2.93]2.51 [1.45, 3.41]21% [0%, 50%]50%79%-0.03+0.272026-08-07 → 2026-08-30
tmin12Zbilinear30d24 2 QC3.38 [2.41, 4.40]1.44+3.34 [2.35, 4.40]3.82 [2.88, 4.71]17% [4%, 32%]21%33%-0.62+0.222026-08-07 → 2026-08-30
tmin12Zbilinear90d24 2 QC3.38 [2.36, 4.50]1.44+3.34 [2.30, 4.50]3.82 [2.86, 4.81]17% [0%, 33%]21%33%-0.62+0.222026-08-07 → 2026-08-30
tmin12Zbilinear365d24 2 QC3.38 [2.36, 4.74]1.44+3.34 [2.31, 4.74]3.82 [2.86, 4.97]17% [0%, 35%]21%33%-0.62+0.222026-08-07 → 2026-08-30
tmin12Zbilinearall24 2 QC3.38 [2.28, 4.66]1.44+3.34 [2.22, 4.65]3.82 [2.78, 4.89]17% [0%, 36%]21%33%-0.62+0.222026-08-07 → 2026-08-30
tmin12Znearest30d24 2 QC2.35 [1.67, 3.16]1.62+1.70 [0.62, 2.84]2.69 [1.82, 3.44]12% [0%, 22%]50%71%-0.13+0.112026-08-07 → 2026-08-30
tmin12Znearest90d24 2 QC2.35 [1.61, 3.21]1.62+1.70 [0.56, 2.99]2.69 [1.68, 3.50]12% [0%, 25%]50%71%-0.13+0.112026-08-07 → 2026-08-30
tmin12Znearest365d24 2 QC2.35 [1.61, 3.37]1.62+1.70 [0.53, 3.21]2.69 [1.69, 3.63]12% [0%, 25%]50%71%-0.13+0.112026-08-07 → 2026-08-30
tmin12Znearestall24 2 QC2.35 [1.61, 3.37]1.62+1.70 [0.49, 3.14]2.69 [1.69, 3.62]12% [0%, 24%]50%71%-0.13+0.112026-08-07 → 2026-08-30

+ model too warm · − model too cold · bias interval includes zero · ★ lowest MAE · = not distinguishable from the leader · ▼ significantly worse · n < 30 greyed and unranked · CI is a 95 % moving-block bootstrap interval.

Daily error, last 90 days

Daily forecast minus observed error in °F for NCEP GFS at KLAX, lead day 6, 00Z bilinear tmax+10+50-5-102026-08-07: -2.34 °F2026-08-08: +1.27 °F2026-08-09: +0.22 °F2026-08-10: +1.5 °F2026-08-11: -0.46 °F2026-08-12: +0.79 °F2026-08-13: +0.38 °F2026-08-14: -2.73 °F2026-08-15: -3.21 °F2026-08-16: +0.25 °F2026-08-17: -0.46 °F2026-08-18: -0.32 °F2026-08-19: -1.66 °F2026-08-20: +4.69 °F2026-08-21: +2.18 °F2026-08-22: +1.39 °F2026-08-23: -1.03 °F2026-08-24: -1.09 °F2026-08-25: -2.04 °F2026-08-26: -6.31 °F2026-08-27: -6.07 °F2026-08-28: -1.54 °F2026-08-29: -2.25 °F2026-08-30: -0.59 °F2026-08-072026-08-30°F, forecast − observed
Forecast − observed, °F, 00Z bilinear daily maximum. The dashed line is zero; the thick line is a centred 7-day mean, drawn only where the whole window is present. Gaps are days with no score, never interpolation. Hover a point for its date and value.
The same series as a table (24 days, newest first) · download CSV
Climatological dayError °F
2026-08-30-0.59
2026-08-29-2.25
2026-08-28-1.54
2026-08-27-6.07
2026-08-26-6.31
2026-08-25-2.04
2026-08-24-1.09
2026-08-23-1.03
2026-08-22+1.39
2026-08-21+2.18
2026-08-20+4.69
2026-08-19-1.66
2026-08-18-0.32
2026-08-17-0.46
2026-08-16+0.25
2026-08-15-3.21
2026-08-14-2.73
2026-08-13+0.38
2026-08-12+0.79
2026-08-11-0.46
2026-08-10+1.50
2026-08-09+0.22
2026-08-08+1.27
2026-08-07-2.34

Error distribution

Distribution of the signed daily error in °F for NCEP GFS at KLAX, lead day 6-10 to -9 °F: 0 days-9 to -8 °F: 0 days-8 to -7 °F: 0 days-7 to -6 °F: 2 days-6 to -5 °F: 0 days-5 to -4 °F: 0 days-4 to -3 °F: 1 day-3 to -2 °F: 4 days-2 to -1 °F: 4 days-1 to 0 °F: 4 days0 to 1 °F: 4 days1 to 2 °F: 3 days2 to 3 °F: 1 day3 to 4 °F: 0 days4 to 5 °F: 1 day5 to 6 °F: 0 days6 to 7 °F: 0 days7 to 8 °F: 0 days8 to 9 °F: 0 days9 to 10 °F: 0 daysdashed: P50 |e| 1.44 · P90 |e| 4.24 °F-100+10 °Fn = 24 days
All scored days for 00Z bilinear daily maximum, 20 equal bins. The dashed marks are the 50th and 90th percentiles of the absolute error, mirrored on both sides. Hover a bar for its bin and count.
Bin counts as a table
From °FTo °FDays
-10.00-9.000
-9.00-8.000
-8.00-7.000
-7.00-6.002
-6.00-5.000
-5.00-4.000
-4.00-3.001
-3.00-2.004
-2.00-1.004
-1.00+0.004
+0.00+1.004
+1.00+2.003
+2.00+3.001
+3.00+4.000
+4.00+5.001
+5.00+6.000
+6.00+7.000
+7.00+8.000
+8.00+9.000
+9.00+10.000

Month by month

00Z bilinear daily maximum, newest first.

Monthn MAE °FBias °F
2026-08241.86 -0.81

Availability

ModelScored period DaysCoverage
NCEP GFS2026-08-07 → 2026-08-30 24
NCEP GFS2026-08-07 → 2026-08-30 24
NCEP GFS2026-08-07 → 2026-08-30 24
NCEP GFS2026-08-07 → 2026-08-30 24

Compared with other models

Paired bootstrap on the days both models cover (90d, 00Z, bilinear, daily maximum). Negative means NCEP GFS has the lower MAE. "Distinguishable" means the 95 % interval excludes zero.

Other modelCommon days MAE difference °FDistinguishable
ECMWF AIFS Single 24 -0.29 [-0.89, 0.30] no
GraphCast (IFS init) 24 -2.29 [-3.14, -1.45] yes
ECMWF IFS HRES 19 -0.30 [-1.17, 0.87] no
Persistence (baseline) 24 -1.22 [-2.13, 0.11] no

Cite this page

ShortCastCheck, KLAX gfs lead 6, methodology v0.2, accessed 2026-08-31, https://castcheck.zifanzhang.com/station/KLAX/model/gfs/lead/6/

LongCastCheck (2026). Station-level verification of raw weather-model 2 m temperature forecasts: KLAX (Los Angeles Intl), model gfs, lead day 6. Methodology version 0.2, schema version 0.1, data through 2026-08-30. Accessed 2026-08-31. https://castcheck.zifanzhang.com/station/KLAX/model/gfs/lead/6/

Accessed2026-08-31 (data through 2026-08-30; page built 2026-08-31T03:52:06+00:00)

JSON CSV all scores methodology v0.2 licence