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

Los Angeles Intl · NCEP GFS · lead day 3

KLAX · gfs · lead 3

Target day = initialization date + 3 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
tmax00Zbilinear30d27 2 QC2.11 [1.61, 2.77]2.12-0.43 [-1.93, 0.88]2.70 [2.03, 3.38]33% [17%, 47%]63%78%+0.04+0.042026-08-04 → 2026-08-30
tmax00Zbilinear90d27 2 QC2.11 [1.53, 2.80]2.12-0.43 [-2.17, 1.23]2.70 [1.81, 3.41]33% [14%, 47%]63%78%+0.04+0.042026-08-04 → 2026-08-30
tmax00Zbilinear365d27 2 QC2.11 [1.56, 3.00]2.12-0.43 [-2.50, 1.26]2.70 [1.86, 3.57]33% [14%, 47%]63%78%+0.04+0.042026-08-04 → 2026-08-30
tmax00Zbilinearall27 2 QC2.11 [1.51, 2.94]2.12-0.43 [-2.35, 1.10]2.70 [1.84, 3.49]33% [12%, 48%]63%78%+0.04+0.042026-08-04 → 2026-08-30
tmax00Znearest30d27 2 QC2.32 [1.47, 3.13]2.15-1.22 [-2.38, -0.13]2.90 [1.92, 3.70]19% [3%, 43%]52%74%-0.06+0.032026-08-04 → 2026-08-30
tmax00Znearest90d27 2 QC2.32 [1.22, 3.23]2.15-1.22 [-2.64, 0.07]2.90 [1.59, 3.78]19% [0%, 50%]52%74%-0.06+0.032026-08-04 → 2026-08-30
tmax00Znearest365d27 2 QC2.32 [1.30, 3.47]2.15-1.22 [-2.94, 0.11]2.90 [1.63, 3.94]19% [0%, 47%]52%74%-0.06+0.032026-08-04 → 2026-08-30
tmax00Znearestall27 2 QC2.32 [1.35, 3.37]2.15-1.22 [-2.82, 0.07]2.90 [1.69, 3.88]19% [0%, 50%]52%74%-0.06+0.032026-08-04 → 2026-08-30
tmax12Zbilinear30d27 2 QC2.02 [1.44, 2.66]2.05-0.59 [-1.89, 0.56]2.65 [1.79, 3.41]26% [13%, 38%]67%78%+0.08+0.072026-08-04 → 2026-08-30
tmax12Zbilinear90d27 2 QC2.02 [1.34, 2.70]2.05-0.59 [-2.10, 0.88]2.65 [1.62, 3.40]26% [12%, 39%]67%78%+0.08+0.072026-08-04 → 2026-08-30
tmax12Zbilinear365d27 2 QC2.02 [1.36, 2.84]2.05-0.59 [-2.35, 0.89]2.65 [1.66, 3.58]26% [11%, 39%]67%78%+0.08+0.072026-08-04 → 2026-08-30
tmax12Zbilinearall27 2 QC2.02 [1.36, 2.80]2.05-0.59 [-2.26, 0.77]2.65 [1.63, 3.48]26% [10%, 38%]67%78%+0.08+0.072026-08-04 → 2026-08-30
tmax12Znearest30d27 2 QC2.37 [1.24, 3.26]2.23-1.27 [-2.42, -0.15]3.01 [1.88, 3.78]33% [7%, 68%]52%63%-0.08-0.012026-08-04 → 2026-08-30
tmax12Znearest90d27 2 QC2.37 [1.07, 3.27]2.23-1.27 [-2.68, -0.01]3.01 [1.61, 3.81]33% [6%, 79%]52%63%-0.08-0.012026-08-04 → 2026-08-30
tmax12Znearest365d27 2 QC2.37 [1.06, 3.45]2.23-1.27 [-2.87, 0.02]3.01 [1.60, 4.00]33% [4%, 79%]52%63%-0.08-0.012026-08-04 → 2026-08-30
tmax12Znearestall27 2 QC2.37 [1.06, 3.40]2.23-1.27 [-2.87, -0.03]3.01 [1.61, 3.93]33% [4%, 78%]52%63%-0.08-0.012026-08-04 → 2026-08-30
tmin00Zbilinear30d27 2 QC3.82 [2.86, 4.67]1.40+3.71 [2.57, 4.67]4.14 [3.25, 4.83]11% [0%, 30%]15%26%-1.58-0.022026-08-04 → 2026-08-30
tmin00Zbilinear90d27 2 QC3.82 [2.80, 4.74]1.40+3.71 [2.54, 4.74]4.14 [3.21, 4.88]11% [0%, 30%]15%26%-1.58-0.022026-08-04 → 2026-08-30
tmin00Zbilinear365d27 2 QC3.82 [2.64, 4.78]1.40+3.71 [2.39, 4.78]4.14 [3.04, 4.92]11% [0%, 32%]15%26%-1.58-0.022026-08-04 → 2026-08-30
tmin00Zbilinearall27 2 QC3.82 [2.60, 4.82]1.40+3.71 [2.40, 4.82]4.14 [3.06, 4.95]11% [0%, 31%]15%26%-1.58-0.022026-08-04 → 2026-08-30
tmin00Znearest30d27 2 QC2.61 [1.86, 3.34]1.59+2.18 [0.99, 3.25]2.98 [2.19, 3.59]15% [4%, 27%]33%63%-0.76-0.162026-08-04 → 2026-08-30
tmin00Znearest90d27 2 QC2.61 [1.71, 3.39]1.59+2.18 [0.84, 3.33]2.98 [2.08, 3.63]15% [0%, 29%]33%63%-0.76-0.162026-08-04 → 2026-08-30
tmin00Znearest365d27 2 QC2.61 [1.67, 3.46]1.59+2.18 [0.79, 3.38]2.98 [1.98, 3.69]15% [0%, 33%]33%63%-0.76-0.162026-08-04 → 2026-08-30
tmin00Znearestall27 2 QC2.61 [1.68, 3.45]1.59+2.18 [0.75, 3.42]2.98 [2.03, 3.70]15% [0%, 33%]33%63%-0.76-0.162026-08-04 → 2026-08-30
tmin12Zbilinear30d27 2 QC3.58 [2.65, 4.41]1.50+3.44 [2.27, 4.41]3.93 [3.03, 4.63]7% [0%, 20%]22%37%-1.42-0.092026-08-04 → 2026-08-30
tmin12Zbilinear90d27 2 QC3.58 [2.59, 4.47]1.50+3.44 [2.24, 4.47]3.93 [2.92, 4.70]7% [0%, 20%]22%37%-1.42-0.092026-08-04 → 2026-08-30
tmin12Zbilinear365d27 2 QC3.58 [2.43, 4.54]1.50+3.44 [2.10, 4.54]3.93 [2.81, 4.76]7% [0%, 21%]22%37%-1.42-0.092026-08-04 → 2026-08-30
tmin12Zbilinearall27 2 QC3.58 [2.45, 4.58]1.50+3.44 [2.13, 4.58]3.93 [2.81, 4.77]7% [0%, 21%]22%37%-1.42-0.092026-08-04 → 2026-08-30
tmin12Znearest30d27 2 QC2.45 [1.73, 3.16]1.63+1.99 [0.81, 3.04]2.83 [2.10, 3.46]19% [7%, 33%]41%63%-0.65-0.192026-08-04 → 2026-08-30
tmin12Znearest90d27 2 QC2.45 [1.64, 3.25]1.63+1.99 [0.76, 3.15]2.83 [1.98, 3.52]19% [4%, 35%]41%63%-0.65-0.192026-08-04 → 2026-08-30
tmin12Znearest365d27 2 QC2.45 [1.53, 3.32]1.63+1.99 [0.61, 3.29]2.83 [1.88, 3.61]19% [0%, 37%]41%63%-0.65-0.192026-08-04 → 2026-08-30
tmin12Znearestall27 2 QC2.45 [1.57, 3.29]1.63+1.99 [0.59, 3.28]2.83 [1.92, 3.58]19% [0%, 36%]41%63%-0.65-0.192026-08-04 → 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 3, 00Z bilinear tmax+10+50-5-102026-08-04: +1.73 °F2026-08-05: +2.3 °F2026-08-06: +1.65 °F2026-08-07: +0.54 °F2026-08-08: +1.86 °F2026-08-09: +0.31 °F2026-08-10: +1.62 °F2026-08-11: -0.97 °F2026-08-12: -1.18 °F2026-08-13: -2.97 °F2026-08-14: -5.23 °F2026-08-15: -0.69 °F2026-08-16: +1.57 °F2026-08-17: +2.91 °F2026-08-18: -0.27 °F2026-08-19: +1.51 °F2026-08-20: +5.42 °F2026-08-21: -0.9 °F2026-08-22: -0.16 °F2026-08-23: -3.13 °F2026-08-24: +0.87 °F2026-08-25: +0.37 °F2026-08-26: -2.71 °F2026-08-27: -6.99 °F2026-08-28: -1.67 °F2026-08-29: -3.17 °F2026-08-30: -4.18 °F2026-08-042026-08-30°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 (27 days, newest first) · download CSV
Climatological dayError °F
2026-08-30-4.18
2026-08-29-3.17
2026-08-28-1.67
2026-08-27-6.99
2026-08-26-2.71
2026-08-25+0.37
2026-08-24+0.87
2026-08-23-3.13
2026-08-22-0.16
2026-08-21-0.90
2026-08-20+5.42
2026-08-19+1.51
2026-08-18-0.27
2026-08-17+2.91
2026-08-16+1.57
2026-08-15-0.69
2026-08-14-5.23
2026-08-13-2.97
2026-08-12-1.18
2026-08-11-0.97
2026-08-10+1.62
2026-08-09+0.31
2026-08-08+1.86
2026-08-07+0.54
2026-08-06+1.65
2026-08-05+2.30
2026-08-04+1.73

Error distribution

Distribution of the signed daily error in °F for NCEP GFS at KLAX, lead day 3-10 to -9 °F: 0 days-9 to -8 °F: 0 days-8 to -7 °F: 0 days-7 to -6 °F: 1 day-6 to -5 °F: 1 day-5 to -4 °F: 1 day-4 to -3 °F: 2 days-3 to -2 °F: 2 days-2 to -1 °F: 2 days-1 to 0 °F: 5 days0 to 1 °F: 4 days1 to 2 °F: 6 days2 to 3 °F: 2 days3 to 4 °F: 0 days4 to 5 °F: 0 days5 to 6 °F: 1 day6 to 7 °F: 0 days7 to 8 °F: 0 days8 to 9 °F: 0 days9 to 10 °F: 0 daysdashed: P50 |e| 1.65 · P90 |e| 4.6 °F-100+10 °Fn = 27 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
-7.00-6.001
-6.00-5.001
-5.00-4.001
-4.00-3.002
-3.00-2.002
-2.00-1.002
-1.00+0.005
+0.00+1.004
+1.00+2.006
+2.00+3.002
+3.00+4.000
+4.00+5.000
+5.00+6.001
+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
2026-08272.11 -0.43

Availability

ModelScored period DaysCoverage
NCEP GFS2026-08-04 → 2026-08-30 27
NCEP GFS2026-08-04 → 2026-08-30 27
NCEP GFS2026-08-04 → 2026-08-30 27
NCEP GFS2026-08-04 → 2026-08-30 27

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 27 +0.41 [-0.14, 1.11] no
GraphCast (IFS init) 25 -1.67 [-2.35, -1.06] yes
ECMWF IFS HRES 22 +0.07 [-0.93, 1.39] no
Persistence (baseline) 27 -0.08 [-0.66, 0.48] no

Cite this page

ShortCastCheck, KLAX gfs lead 3, methodology v0.2, accessed 2026-08-31, https://castcheck.zifanzhang.com/station/KLAX/model/gfs/lead/3/

LongCastCheck (2026). Station-level verification of raw weather-model 2 m temperature forecasts: KLAX (Los Angeles Intl), model gfs, lead day 3. 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/3/

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