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

Los Angeles Intl · NCEP GFS · lead day 0

KLAX · gfs · lead 0

Target day = initialization date + 0 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
tmax00Zbilinear30d30 2 QC2.09 [1.61, 2.54]1.92-0.81 [-1.89, 0.35]2.56 [1.83, 3.19]30% [13%, 43%]50%83%——2026-08-01 → 2026-08-30
tmax00Zbilinear90d30 2 QC2.09 [1.57, 2.63]1.92-0.81 [-2.22, 0.70]2.56 [1.79, 3.30]30% [14%, 45%]50%83%——2026-08-01 → 2026-08-30
tmax00Zbilinear365d30 2 QC2.09 [1.58, 2.71]1.92-0.81 [-2.46, 0.68]2.56 [1.78, 3.43]30% [11%, 44%]50%83%——2026-08-01 → 2026-08-30
tmax00Zbilinearall30 2 QC2.09 [1.54, 2.72]1.92-0.81 [-2.27, 0.66]2.56 [1.76, 3.37]30% [13%, 46%]50%83%——2026-08-01 → 2026-08-30
tmax00Znearest30d30 2 QC2.49 [1.71, 3.22]2.05-1.66 [-2.75, -0.52]3.05 [2.02, 3.77]27% [10%, 50%]47%70%——2026-08-01 → 2026-08-30
tmax00Znearest90d30 2 QC2.49 [1.48, 3.44]2.05-1.66 [-3.09, -0.25]3.05 [1.77, 3.92]27% [5%, 56%]47%70%——2026-08-01 → 2026-08-30
tmax00Znearest365d30 2 QC2.49 [1.45, 3.52]2.05-1.66 [-3.38, -0.13]3.05 [1.73, 4.03]27% [0%, 57%]47%70%——2026-08-01 → 2026-08-30
tmax00Znearestall30 2 QC2.49 [1.45, 3.47]2.05-1.66 [-3.11, -0.30]3.05 [1.81, 3.99]27% [6%, 60%]47%70%——2026-08-01 → 2026-08-30
tmin00Zbilinear30d30 2 QC2.94 [2.06, 3.76]1.29+2.84 [1.81, 3.76]3.22 [2.39, 3.91]7% [0%, 20%]33%43%——2026-08-01 → 2026-08-30
tmin00Zbilinear90d30 2 QC2.94 [2.09, 3.86]1.29+2.84 [1.81, 3.86]3.22 [2.38, 3.96]7% [0%, 19%]33%43%——2026-08-01 → 2026-08-30
tmin00Zbilinear365d30 2 QC2.94 [1.96, 3.94]1.29+2.84 [1.67, 3.94]3.22 [2.29, 4.01]7% [0%, 20%]33%43%——2026-08-01 → 2026-08-30
tmin00Zbilinearall30 2 QC2.94 [2.05, 3.97]1.29+2.84 [1.81, 3.97]3.22 [2.33, 4.06]7% [0%, 19%]33%43%——2026-08-01 → 2026-08-30
tmin00Znearest30d30 2 QC1.87 [1.21, 2.57]1.41+1.47 [0.48, 2.43]2.21 [1.56, 2.78]33% [10%, 57%]47%87%——2026-08-01 → 2026-08-30
tmin00Znearest90d30 2 QC1.87 [1.16, 2.64]1.41+1.47 [0.43, 2.52]2.21 [1.50, 2.83]33% [9%, 57%]47%87%——2026-08-01 → 2026-08-30
tmin00Znearest365d30 2 QC1.87 [1.16, 2.70]1.41+1.47 [0.29, 2.62]2.21 [1.48, 2.85]33% [6%, 57%]47%87%——2026-08-01 → 2026-08-30
tmin00Znearestall30 2 QC1.87 [1.15, 2.76]1.41+1.47 [0.42, 2.71]2.21 [1.48, 2.90]33% [6%, 57%]47%87%——2026-08-01 → 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 0, 00Z bilinear tmax+10+50-5-102026-08-01: +1.34 °F2026-08-02: +1.83 °F2026-08-03: +2.75 °F2026-08-04: +0.53 °F2026-08-05: +2.75 °F2026-08-06: -0.73 °F2026-08-07: -0.98 °F2026-08-08: +2.06 °F2026-08-09: +1.5 °F2026-08-10: -0.78 °F2026-08-11: -2.37 °F2026-08-12: -3.09 °F2026-08-13: -4.36 °F2026-08-14: -3.87 °F2026-08-15: -2.27 °F2026-08-16: +1.57 °F2026-08-17: +1.75 °F2026-08-18: -2.28 °F2026-08-19: -0.61 °F2026-08-20: +2.76 °F2026-08-21: -2.36 °F2026-08-22: +0.35 °F2026-08-23: -1.47 °F2026-08-24: -0.84 °F2026-08-25: -0.74 °F2026-08-26: -2.67 °F2026-08-27: -7.8 °F2026-08-28: -0.44 °F2026-08-29: -3.28 °F2026-08-30: -2.44 °F2026-08-012026-08-30°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 (30 days, newest first) · download CSV
Climatological dayError °F
2026-08-30-2.44
2026-08-29-3.28
2026-08-28-0.44
2026-08-27-7.80
2026-08-26-2.67
2026-08-25-0.74
2026-08-24-0.84
2026-08-23-1.47
2026-08-22+0.35
2026-08-21-2.36
2026-08-20+2.76
2026-08-19-0.61
2026-08-18-2.28
2026-08-17+1.75
2026-08-16+1.57
2026-08-15-2.27
2026-08-14-3.87
2026-08-13-4.36
2026-08-12-3.09
2026-08-11-2.37
2026-08-10-0.78
2026-08-09+1.50
2026-08-08+2.06
2026-08-07-0.98
2026-08-06-0.73
2026-08-05+2.75
2026-08-04+0.53
2026-08-03+2.75
2026-08-02+1.83
2026-08-01+1.34

Error distribution

Distribution of the signed daily error in °F for NCEP GFS at KLAX, lead day 0-10 to -9 °F: 0 days-9 to -8 °F: 0 days-8 to -7 °F: 1 day-7 to -6 °F: 0 days-6 to -5 °F: 0 days-5 to -4 °F: 1 day-4 to -3 °F: 3 days-3 to -2 °F: 6 days-2 to -1 °F: 1 day-1 to 0 °F: 7 days0 to 1 °F: 2 days1 to 2 °F: 5 days2 to 3 °F: 4 days3 to 4 °F: 0 days4 to 5 °F: 0 days5 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| 1.95 · P90 |e| 3.34 °F-100+10 °Fn = 30 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
-8.00-7.001
-7.00-6.000
-6.00-5.000
-5.00-4.001
-4.00-3.003
-3.00-2.006
-2.00-1.001
-1.00+0.007
+0.00+1.002
+1.00+2.005
+2.00+3.004
+3.00+4.000
+4.00+5.000
+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
2026-08302.09 -0.81

Availability

ModelScored period DaysCoverage
NCEP GFS2026-08-01 → 2026-08-30 30
NCEP GFS2026-08-01 → 2026-08-30 30

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 30 +0.60 [0.04, 1.21] yes
Aurora (GFS init) 2 -3.05 [-3.50, -2.59] yes
Aurora (IFS init) 3 -2.58 [-2.74, -2.50] yes
FourCastNet v2 (GFS init) 2 -0.46 [-1.45, 0.53] no
FourCastNet v2 (IFS init) 3 -0.67 [-1.43, -0.30] yes
GraphCast (GFS init) 2 -2.71 [-2.76, -2.66] yes
GraphCast (IFS init) 28 -1.45 [-2.29, -0.86] yes
ECMWF IFS HRES 25 -0.20 [-0.72, 0.56] no
Pangu-Weather (GFS init) 2 +0.39 [-0.35, 1.13] no
Pangu-Weather (IFS init) 3 -0.08 [-0.61, 0.19] no

Cite this page

ShortCastCheck, KLAX gfs lead 0, methodology v0.2, accessed 2026-08-31, https://castcheck.zifanzhang.com/station/KLAX/model/gfs/lead/0/

LongCastCheck (2026). Station-level verification of raw weather-model 2 m temperature forecasts: KLAX (Los Angeles Intl), model gfs, lead day 0. 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/0/

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

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