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

Los Angeles Intl · NCEP GFS · lead day 8

KLAX · gfs · lead 8

Target day = initialization date + 8 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
tmax00Zbilinear30d22 2 QC2.99 [2.16, 3.94]2.87-1.16 [-3.12, 0.58]3.73 [2.88, 4.61]23% [10%, 38%]45%50%+0.11+0.092026-08-09 → 2026-08-30
tmax00Zbilinear90d22 2 QC2.99 [2.01, 3.97]2.87-1.16 [-3.47, 0.56]3.73 [2.77, 4.66]23% [10%, 44%]45%50%+0.11+0.092026-08-09 → 2026-08-30
tmax00Zbilinear365d22 2 QC2.99 [2.04, 4.00]2.87-1.16 [-3.48, 0.65]3.73 [2.83, 4.76]23% [9%, 43%]45%50%+0.11+0.092026-08-09 → 2026-08-30
tmax00Zbilinearall22 2 QC2.99 [2.02, 3.99]2.87-1.16 [-3.47, 0.86]3.73 [2.77, 4.75]23% [11%, 43%]45%50%+0.11+0.092026-08-09 → 2026-08-30
tmax00Znearest30d22 2 QC3.23 [2.39, 4.15]3.02-1.28 [-3.41, 0.63]4.09 [3.13, 5.08]23% [7%, 43%]36%50%+0.04+0.042026-08-09 → 2026-08-30
tmax00Znearest90d22 2 QC3.23 [2.23, 4.16]3.02-1.28 [-3.78, 0.72]4.09 [3.03, 5.11]23% [5%, 50%]36%50%+0.04+0.042026-08-09 → 2026-08-30
tmax00Znearest365d22 2 QC3.23 [2.22, 4.24]3.02-1.28 [-3.84, 0.64]4.09 [3.05, 5.26]23% [0%, 50%]36%50%+0.04+0.042026-08-09 → 2026-08-30
tmax00Znearestall22 2 QC3.23 [2.18, 4.20]3.02-1.28 [-3.80, 0.72]4.09 [3.00, 5.23]23% [6%, 50%]36%50%+0.04+0.042026-08-09 → 2026-08-30
tmax12Zbilinear30d22 2 QC2.82 [1.08, 4.40]2.73-1.42 [-3.26, -0.06]3.89 [1.60, 5.48]36% [6%, 77%]45%55%+0.16+0.132026-08-09 → 2026-08-30
tmax12Zbilinear90d22 2 QC2.82 [0.65, 4.59]2.73-1.42 [-3.57, 0.05]3.89 [0.85, 5.67]36% [0%, 100%]45%55%+0.16+0.132026-08-09 → 2026-08-30
tmax12Zbilinear365d22 2 QC2.82 [0.64, 4.63]2.73-1.42 [-3.58, 0.02]3.89 [0.92, 5.70]36% [0%, 100%]45%55%+0.16+0.132026-08-09 → 2026-08-30
tmax12Zbilinearall22 2 QC2.82 [0.68, 4.58]2.73-1.42 [-3.59, 0.08]3.89 [0.92, 5.74]36% [0%, 96%]45%55%+0.16+0.132026-08-09 → 2026-08-30
tmax12Znearest30d22 2 QC3.11 [1.58, 4.55]2.80-1.90 [-3.61, -0.65]4.23 [1.97, 5.90]18% [4%, 35%]45%59%+0.08+0.112026-08-09 → 2026-08-30
tmax12Znearest90d22 2 QC3.11 [1.27, 4.69]2.80-1.90 [-3.95, -0.56]4.23 [1.36, 6.06]18% [0%, 38%]45%59%+0.08+0.112026-08-09 → 2026-08-30
tmax12Znearest365d22 2 QC3.11 [1.24, 4.78]2.80-1.90 [-4.05, -0.58]4.23 [1.38, 6.07]18% [0%, 38%]45%59%+0.08+0.112026-08-09 → 2026-08-30
tmax12Znearestall22 2 QC3.11 [1.26, 4.76]2.80-1.90 [-4.00, -0.51]4.23 [1.41, 6.17]18% [0%, 38%]45%59%+0.08+0.112026-08-09 → 2026-08-30
tmin00Zbilinear30d22 2 QC3.32 [2.42, 4.07]2.12+2.87 [1.38, 3.93]3.90 [2.79, 4.71]5% [0%, 12%]36%55%-0.43-0.062026-08-09 → 2026-08-30
tmin00Zbilinear90d22 2 QC3.32 [2.26, 4.08]2.12+2.87 [1.05, 3.97]3.90 [2.59, 4.72]5% [0%, 14%]36%55%-0.43-0.062026-08-09 → 2026-08-30
tmin00Zbilinear365d22 2 QC3.32 [2.26, 4.15]2.12+2.87 [1.05, 4.13]3.90 [2.57, 4.76]5% [0%, 14%]36%55%-0.43-0.062026-08-09 → 2026-08-30
tmin00Zbilinearall22 2 QC3.32 [2.28, 4.22]2.12+2.87 [1.20, 4.15]3.90 [2.64, 4.81]5% [0%, 14%]36%55%-0.43-0.062026-08-09 → 2026-08-30
tmin00Znearest30d22 2 QC2.51 [1.79, 3.15]2.22+1.41 [-0.49, 2.72]3.19 [2.23, 3.98]27% [15%, 40%]50%55%-0.08-0.122026-08-09 → 2026-08-30
tmin00Znearest90d22 2 QC2.51 [1.74, 3.22]2.22+1.41 [-0.86, 2.81]3.19 [2.13, 4.02]27% [14%, 43%]50%55%-0.08-0.122026-08-09 → 2026-08-30
tmin00Znearest365d22 2 QC2.51 [1.72, 3.25]2.22+1.41 [-0.77, 3.02]3.19 [2.14, 4.10]27% [14%, 43%]50%55%-0.08-0.122026-08-09 → 2026-08-30
tmin00Znearestall22 2 QC2.51 [1.73, 3.26]2.22+1.41 [-0.72, 2.82]3.19 [2.09, 4.12]27% [14%, 42%]50%55%-0.08-0.122026-08-09 → 2026-08-30
tmin12Zbilinear30d22 2 QC3.33 [2.67, 4.07]2.01+3.03 [2.05, 4.03]3.90 [3.12, 4.61]18% [7%, 29%]32%45%-0.43-0.012026-08-09 → 2026-08-30
tmin12Zbilinear90d22 2 QC3.33 [2.59, 4.09]2.01+3.03 [1.94, 4.04]3.90 [3.08, 4.64]18% [3%, 29%]32%45%-0.43-0.012026-08-09 → 2026-08-30
tmin12Zbilinear365d22 2 QC3.33 [2.58, 4.13]2.01+3.03 [1.97, 4.12]3.90 [3.07, 4.75]18% [0%, 29%]32%45%-0.43-0.012026-08-09 → 2026-08-30
tmin12Zbilinearall22 2 QC3.33 [2.59, 4.19]2.01+3.03 [1.92, 4.19]3.90 [3.06, 4.78]18% [0%, 29%]32%45%-0.43-0.012026-08-09 → 2026-08-30
tmin12Znearest30d22 2 QC2.21 [1.43, 2.84]1.98+1.55 [0.43, 2.63]2.74 [1.97, 3.28]27% [14%, 47%]45%64%+0.05+0.002026-08-09 → 2026-08-30
tmin12Znearest90d22 2 QC2.21 [1.30, 2.88]1.98+1.55 [0.21, 2.70]2.74 [1.76, 3.29]27% [13%, 50%]45%64%+0.05+0.002026-08-09 → 2026-08-30
tmin12Znearest365d22 2 QC2.21 [1.30, 2.87]1.98+1.55 [0.24, 2.83]2.74 [1.76, 3.34]27% [14%, 50%]45%64%+0.05+0.002026-08-09 → 2026-08-30
tmin12Znearestall22 2 QC2.21 [1.32, 2.93]1.98+1.55 [0.22, 2.84]2.74 [1.76, 3.36]27% [14%, 50%]45%64%+0.05+0.002026-08-09 → 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 8, 00Z bilinear tmax+10+50-5-102026-08-09: -5.38 °F2026-08-10: +0.32 °F2026-08-11: -1.34 °F2026-08-12: +1.12 °F2026-08-13: +0.08 °F2026-08-14: -0.84 °F2026-08-15: +5.21 °F2026-08-16: +5.17 °F2026-08-17: +1.44 °F2026-08-18: -4.54 °F2026-08-19: -3.09 °F2026-08-20: +3.62 °F2026-08-21: -4.72 °F2026-08-22: -0.42 °F2026-08-23: +2.18 °F2026-08-24: -1.57 °F2026-08-25: -1.17 °F2026-08-26: -4.18 °F2026-08-27: -8.94 °F2026-08-28: -4.45 °F2026-08-29: -4.96 °F2026-08-30: +0.97 °F2026-08-092026-08-30°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 (22 days, newest first) · download CSV
Climatological dayError °F
2026-08-30+0.97
2026-08-29-4.96
2026-08-28-4.45
2026-08-27-8.94
2026-08-26-4.18
2026-08-25-1.17
2026-08-24-1.57
2026-08-23+2.18
2026-08-22-0.42
2026-08-21-4.72
2026-08-20+3.62
2026-08-19-3.09
2026-08-18-4.54
2026-08-17+1.44
2026-08-16+5.17
2026-08-15+5.21
2026-08-14-0.84
2026-08-13+0.08
2026-08-12+1.12
2026-08-11-1.34
2026-08-10+0.32
2026-08-09-5.38

Error distribution

Distribution of the signed daily error in °F for NCEP GFS at KLAX, lead day 8-10 to -9 °F: 0 days-9 to -8 °F: 1 day-8 to -7 °F: 0 days-7 to -6 °F: 0 days-6 to -5 °F: 1 day-5 to -4 °F: 5 days-4 to -3 °F: 1 day-3 to -2 °F: 0 days-2 to -1 °F: 3 days-1 to 0 °F: 2 days0 to 1 °F: 3 days1 to 2 °F: 2 days2 to 3 °F: 1 day3 to 4 °F: 1 day4 to 5 °F: 0 days5 to 6 °F: 2 days6 to 7 °F: 0 days7 to 8 °F: 0 days8 to 9 °F: 0 days9 to 10 °F: 0 daysdashed: P50 |e| 2.64 · P90 |e| 5.21 °F-100+10 °Fn = 22 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
-9.00-8.001
-8.00-7.000
-7.00-6.000
-6.00-5.001
-5.00-4.005
-4.00-3.001
-3.00-2.000
-2.00-1.003
-1.00+0.002
+0.00+1.003
+1.00+2.002
+2.00+3.001
+3.00+4.001
+4.00+5.000
+5.00+6.002
+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
2026-08222.99 -1.16

Availability

ModelScored period DaysCoverage
NCEP GFS2026-08-09 → 2026-08-30 22
NCEP GFS2026-08-09 → 2026-08-30 22
NCEP GFS2026-08-09 → 2026-08-30 22
NCEP GFS2026-08-09 → 2026-08-30 22

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 22 +1.12 [0.58, 1.86] yes
GraphCast (IFS init) 22 -1.91 [-3.89, -0.16] yes
ECMWF IFS HRES 17 +0.31 [-1.65, 3.70] no
Persistence (baseline) 22 -0.38 [-2.53, 1.47] no

Cite this page

ShortCastCheck, KLAX gfs lead 8, methodology v0.2, accessed 2026-08-31, https://castcheck.zifanzhang.com/station/KLAX/model/gfs/lead/8/

LongCastCheck (2026). Station-level verification of raw weather-model 2 m temperature forecasts: KLAX (Los Angeles Intl), model gfs, lead day 8. 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/8/

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