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

Los Angeles Intl · ECMWF AIFS Single · lead day 4

KLAX · aifs_single · lead 4

Target day = initialization date + 4 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, aifs-single-gpid5, 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
tmax00Zbilinear30d26 2 QC1.62 [1.21, 2.20]1.41+0.98 [0.11, 1.76]2.10 [1.48, 2.76]38% [19%, 57%]69%88%+0.35+0.402026-08-05 → 2026-08-30
tmax00Zbilinear90d26 2 QC1.62 [1.16, 2.25]1.41+0.98 [-0.12, 1.77]2.10 [1.41, 2.80]38% [14%, 56%]69%88%+0.35+0.402026-08-05 → 2026-08-30
tmax00Zbilinear365d26 2 QC1.62 [1.16, 2.24]1.41+0.98 [-0.29, 1.85]2.10 [1.42, 2.85]38% [13%, 58%]69%88%+0.35+0.402026-08-05 → 2026-08-30
tmax00Zbilinearall26 2 QC1.62 [1.16, 2.17]1.41+0.98 [-0.15, 1.78]2.10 [1.41, 2.75]38% [14%, 57%]69%88%+0.35+0.402026-08-05 → 2026-08-30
tmax00Znearest30d26 2 QC1.41 [0.97, 1.92]1.40+0.50 [-0.36, 1.25]1.90 [1.30, 2.47]42% [25%, 57%]73%88%+0.44+0.412026-08-05 → 2026-08-30
tmax00Znearest90d26 2 QC1.41 [0.90, 2.03]1.40+0.50 [-0.62, 1.26]1.90 [1.14, 2.54]42% [22%, 59%]73%88%+0.44+0.412026-08-05 → 2026-08-30
tmax00Znearest365d26 2 QC1.41 [0.91, 2.05]1.40+0.50 [-0.82, 1.35]1.90 [1.17, 2.55]42% [19%, 58%]73%88%+0.44+0.412026-08-05 → 2026-08-30
tmax00Znearestall26 2 QC1.41 [0.90, 1.96]1.40+0.50 [-0.64, 1.27]1.90 [1.15, 2.48]42% [20%, 59%]73%88%+0.44+0.412026-08-05 → 2026-08-30
tmax12Zbilinear30d26 2 QC1.39 [0.84, 1.94]1.39+0.61 [-0.10, 1.29]1.89 [1.14, 2.47]50% [32%, 71%]77%85%+0.44+0.412026-08-05 → 2026-08-30
tmax12Zbilinear90d26 2 QC1.39 [0.66, 1.99]1.39+0.61 [-0.25, 1.37]1.89 [0.85, 2.52]50% [29%, 80%]77%85%+0.44+0.412026-08-05 → 2026-08-30
tmax12Zbilinear365d26 2 QC1.39 [0.67, 2.02]1.39+0.61 [-0.25, 1.44]1.89 [0.85, 2.54]50% [29%, 80%]77%85%+0.44+0.412026-08-05 → 2026-08-30
tmax12Zbilinearall26 2 QC1.39 [0.68, 1.96]1.39+0.61 [-0.33, 1.26]1.89 [0.88, 2.49]50% [29%, 79%]77%85%+0.44+0.412026-08-05 → 2026-08-30
tmax12Znearest30d26 2 QC1.35 [0.84, 1.82]1.36+0.12 [-0.59, 0.82]1.80 [1.16, 2.31]50% [35%, 70%]69%85%+0.46+0.422026-08-05 → 2026-08-30
tmax12Znearest90d26 2 QC1.35 [0.67, 1.87]1.36+0.12 [-0.81, 0.87]1.80 [0.84, 2.37]50% [33%, 74%]69%85%+0.46+0.422026-08-05 → 2026-08-30
tmax12Znearest365d26 2 QC1.35 [0.70, 1.91]1.36+0.12 [-0.81, 0.96]1.80 [0.83, 2.38]50% [32%, 71%]69%85%+0.46+0.422026-08-05 → 2026-08-30
tmax12Znearestall26 2 QC1.35 [0.67, 1.87]1.36+0.12 [-0.90, 0.79]1.80 [0.85, 2.37]50% [30%, 73%]69%85%+0.46+0.422026-08-05 → 2026-08-30
tmin00Zbilinear30d26 2 QC0.65 [0.43, 0.92]0.64+0.08 [-0.25, 0.41]0.81 [0.54, 1.07]77% [59%, 93%]100%100%+0.58+0.542026-08-05 → 2026-08-30
tmin00Zbilinear90d26 2 QC0.65 [0.41, 0.97]0.64+0.08 [-0.30, 0.42]0.81 [0.52, 1.10]77% [54%, 94%]100%100%+0.58+0.542026-08-05 → 2026-08-30
tmin00Zbilinear365d26 2 QC0.65 [0.39, 0.99]0.64+0.08 [-0.30, 0.44]0.81 [0.51, 1.12]77% [53%, 95%]100%100%+0.58+0.542026-08-05 → 2026-08-30
tmin00Zbilinearall26 2 QC0.65 [0.40, 0.98]0.64+0.08 [-0.38, 0.44]0.81 [0.49, 1.10]77% [53%, 96%]100%100%+0.58+0.542026-08-05 → 2026-08-30
tmin00Znearest30d26 2 QC0.75 [0.51, 1.06]0.75+0.12 [-0.31, 0.56]0.91 [0.61, 1.22]73% [46%, 93%]96%100%+0.51+0.472026-08-05 → 2026-08-30
tmin00Znearest90d26 2 QC0.75 [0.49, 1.10]0.75+0.12 [-0.36, 0.59]0.91 [0.58, 1.25]73% [42%, 94%]96%100%+0.51+0.472026-08-05 → 2026-08-30
tmin00Znearest365d26 2 QC0.75 [0.49, 1.15]0.75+0.12 [-0.34, 0.62]0.91 [0.58, 1.29]73% [37%, 95%]96%100%+0.51+0.472026-08-05 → 2026-08-30
tmin00Znearestall26 2 QC0.75 [0.48, 1.12]0.75+0.12 [-0.41, 0.62]0.91 [0.56, 1.25]73% [41%, 96%]96%100%+0.51+0.472026-08-05 → 2026-08-30
tmin12Zbilinear30d26 2 QC0.81 [0.61, 1.05]0.78-0.25 [-0.71, 0.23]0.99 [0.78, 1.22]58% [35%, 79%]100%100%+0.48+0.442026-08-05 → 2026-08-30
tmin12Zbilinear90d26 2 QC0.81 [0.58, 1.09]0.78-0.25 [-0.82, 0.26]0.99 [0.75, 1.26]58% [33%, 81%]100%100%+0.48+0.442026-08-05 → 2026-08-30
tmin12Zbilinear365d26 2 QC0.81 [0.57, 1.10]0.78-0.25 [-0.79, 0.31]0.99 [0.73, 1.26]58% [31%, 83%]100%100%+0.48+0.442026-08-05 → 2026-08-30
tmin12Zbilinearall26 2 QC0.81 [0.58, 1.11]0.78-0.25 [-0.85, 0.31]0.99 [0.75, 1.26]58% [31%, 82%]100%100%+0.48+0.442026-08-05 → 2026-08-30
tmin12Znearest30d26 2 QC0.90 [0.70, 1.16]0.88-0.23 [-0.79, 0.35]1.08 [0.87, 1.33]58% [35%, 77%]92%100%+0.42+0.372026-08-05 → 2026-08-30
tmin12Znearest90d26 2 QC0.90 [0.68, 1.22]0.88-0.23 [-0.91, 0.41]1.08 [0.84, 1.37]58% [31%, 79%]92%100%+0.42+0.372026-08-05 → 2026-08-30
tmin12Znearest365d26 2 QC0.90 [0.67, 1.22]0.88-0.23 [-0.86, 0.47]1.08 [0.85, 1.37]58% [29%, 81%]92%100%+0.42+0.372026-08-05 → 2026-08-30
tmin12Znearestall26 2 QC0.90 [0.68, 1.25]0.88-0.23 [-0.92, 0.45]1.08 [0.86, 1.39]58% [29%, 80%]92%100%+0.42+0.372026-08-05 → 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 ECMWF AIFS Single at KLAX, lead day 4, 00Z bilinear tmax+5+2.50-2.5-52026-08-05: +1.58 °F2026-08-06: +1.1 °F2026-08-07: +0.41 °F2026-08-08: +2.74 °F2026-08-09: +0.98 °F2026-08-10: +1.79 °F2026-08-11: +0.34 °F2026-08-12: +0.65 °F2026-08-13: +0.02 °F2026-08-14: -0.48 °F2026-08-15: +2.37 °F2026-08-16: +4.79 °F2026-08-17: +4.67 °F2026-08-18: +0.45 °F2026-08-19: +1.15 °F2026-08-20: +4.62 °F2026-08-21: -1.47 °F2026-08-22: +0.28 °F2026-08-23: +0.32 °F2026-08-24: +1.83 °F2026-08-25: +1.8 °F2026-08-26: +0.26 °F2026-08-27: -2.21 °F2026-08-28: +1.62 °F2026-08-29: -2.06 °F2026-08-30: -2.08 °F2026-08-052026-08-30°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 (26 days, newest first) · download CSV
Climatological dayError °F
2026-08-30-2.08
2026-08-29-2.06
2026-08-28+1.62
2026-08-27-2.21
2026-08-26+0.26
2026-08-25+1.80
2026-08-24+1.83
2026-08-23+0.32
2026-08-22+0.28
2026-08-21-1.47
2026-08-20+4.62
2026-08-19+1.15
2026-08-18+0.45
2026-08-17+4.67
2026-08-16+4.79
2026-08-15+2.37
2026-08-14-0.48
2026-08-13+0.02
2026-08-12+0.65
2026-08-11+0.34
2026-08-10+1.79
2026-08-09+0.98
2026-08-08+2.74
2026-08-07+0.41
2026-08-06+1.10
2026-08-05+1.58

Error distribution

Distribution of the signed daily error in °F for ECMWF AIFS Single at KLAX, lead day 4-5 to -4.5 °F: 0 days-4.5 to -4 °F: 0 days-4 to -3.5 °F: 0 days-3.5 to -3 °F: 0 days-3 to -2.5 °F: 0 days-2.5 to -2 °F: 3 days-2 to -1.5 °F: 0 days-1.5 to -1 °F: 1 day-1 to -0.5 °F: 0 days-0.5 to 0 °F: 1 day0 to 0.5 °F: 7 days0.5 to 1 °F: 2 days1 to 1.5 °F: 2 days1.5 to 2 °F: 5 days2 to 2.5 °F: 1 day2.5 to 3 °F: 1 day3 to 3.5 °F: 0 days3.5 to 4 °F: 0 days4 to 4.5 °F: 0 days4.5 to 5 °F: 3 daysdashed: P50 |e| 1.52 · P90 |e| 3.68 °F-50+5 °Fn = 26 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
-5.00-4.500
-4.50-4.000
-4.00-3.500
-3.50-3.000
-3.00-2.500
-2.50-2.003
-2.00-1.500
-1.50-1.001
-1.00-0.500
-0.50+0.001
+0.00+0.507
+0.50+1.002
+1.00+1.502
+1.50+2.005
+2.00+2.501
+2.50+3.001
+3.00+3.500
+3.50+4.000
+4.00+4.500
+4.50+5.003

Month by month

00Z bilinear daily maximum, newest first.

Monthn MAE °FBias °F
2026-08261.62 +0.98

Availability

ModelScored period DaysCoverage
ECMWF AIFS Single2026-08-05 → 2026-08-30 26
ECMWF AIFS Single2026-08-05 → 2026-08-30 26
ECMWF AIFS Single2026-08-05 → 2026-08-30 26
ECMWF AIFS Single2026-08-05 → 2026-08-30 26

Compared with other models

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

Other modelCommon days MAE difference °FDistinguishable
NCEP GFS 26 -0.56 [-1.64, 0.35] no
GraphCast (IFS init) 25 -2.13 [-3.72, -1.04] yes
ECMWF IFS HRES 20 -0.34 [-0.94, 0.53] no
Persistence (baseline) 26 -0.88 [-1.90, -0.05] yes

Cite this page

ShortCastCheck, KLAX aifs_single lead 4, methodology v0.2, accessed 2026-08-31, https://castcheck.zifanzhang.com/station/KLAX/model/aifs_single/lead/4/

LongCastCheck (2026). Station-level verification of raw weather-model 2 m temperature forecasts: KLAX (Los Angeles Intl), model aifs_single, lead day 4. Methodology version 0.2, schema version 0.1, data through 2026-08-30. Accessed 2026-08-31. https://castcheck.zifanzhang.com/station/KLAX/model/aifs_single/lead/4/

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