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

San Diego Lindbergh · ECMWF AIFS Single · lead day 4

KSAN · 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, 1 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 1 QC3.48 [2.40, 4.35]1.67-3.48 [-4.35, -2.40]4.01 [3.05, 4.72]12% [0%, 30%]31%38%-0.16+0.402026-08-05 → 2026-08-30
tmax00Zbilinear90d26 1 QC3.48 [2.35, 4.39]1.67-3.48 [-4.39, -2.35]4.01 [2.93, 4.74]12% [0%, 29%]31%38%-0.16+0.402026-08-05 → 2026-08-30
tmax00Zbilinear365d26 1 QC3.48 [2.24, 4.44]1.67-3.48 [-4.44, -2.24]4.01 [2.85, 4.82]12% [0%, 32%]31%38%-0.16+0.402026-08-05 → 2026-08-30
tmax00Zbilinearall26 1 QC3.48 [2.24, 4.52]1.67-3.48 [-4.52, -2.24]4.01 [2.81, 4.87]12% [0%, 29%]31%38%-0.16+0.402026-08-05 → 2026-08-30
tmax00Znearest30d26 1 QC4.78 [3.62, 5.78]1.71-4.78 [-5.78, -3.62]5.20 [4.03, 6.07]0% [0%, 0%]8%31%-0.59+0.392026-08-05 → 2026-08-30
tmax00Znearest90d26 1 QC4.78 [3.54, 5.81]1.71-4.78 [-5.81, -3.54]5.20 [3.95, 6.10]0% [0%, 0%]8%31%-0.59+0.392026-08-05 → 2026-08-30
tmax00Znearest365d26 1 QC4.78 [3.45, 5.87]1.71-4.78 [-5.87, -3.45]5.20 [3.85, 6.20]0% [0%, 0%]8%31%-0.59+0.392026-08-05 → 2026-08-30
tmax00Znearestall26 1 QC4.78 [3.42, 5.98]1.71-4.78 [-5.98, -3.42]5.20 [3.81, 6.22]0% [0%, 0%]8%31%-0.59+0.392026-08-05 → 2026-08-30
tmax12Zbilinear30d26 1 QC4.09 [3.09, 4.97]1.78-4.06 [-4.96, -3.07]4.59 [3.57, 5.29]4% [0%, 12%]23%35%-0.36+0.362026-08-05 → 2026-08-30
tmax12Zbilinear90d26 1 QC4.09 [2.99, 5.03]1.78-4.06 [-5.03, -2.97]4.59 [3.49, 5.33]4% [0%, 12%]23%35%-0.36+0.362026-08-05 → 2026-08-30
tmax12Zbilinear365d26 1 QC4.09 [2.91, 5.11]1.78-4.06 [-5.10, -2.86]4.59 [3.45, 5.38]4% [0%, 14%]23%35%-0.36+0.362026-08-05 → 2026-08-30
tmax12Zbilinearall26 1 QC4.09 [2.93, 5.14]1.78-4.06 [-5.14, -2.90]4.59 [3.38, 5.42]4% [0%, 12%]23%35%-0.36+0.362026-08-05 → 2026-08-30
tmax12Znearest30d26 1 QC5.37 [4.26, 6.28]1.78-5.37 [-6.28, -4.26]5.79 [4.64, 6.60]0% [0%, 0%]4%15%-0.79+0.362026-08-05 → 2026-08-30
tmax12Znearest90d26 1 QC5.37 [4.23, 6.37]1.78-5.37 [-6.37, -4.23]5.79 [4.60, 6.65]0% [0%, 0%]4%15%-0.79+0.362026-08-05 → 2026-08-30
tmax12Znearest365d26 1 QC5.37 [4.15, 6.43]1.78-5.37 [-6.43, -4.15]5.79 [4.52, 6.71]0% [0%, 0%]4%15%-0.79+0.362026-08-05 → 2026-08-30
tmax12Znearestall26 1 QC5.37 [4.13, 6.44]1.78-5.37 [-6.44, -4.13]5.79 [4.46, 6.76]0% [0%, 0%]4%15%-0.79+0.362026-08-05 → 2026-08-30
tmin00Zbilinear30d26 1 QC1.09 [0.90, 1.36]0.79-0.72 [-1.25, -0.07]1.27 [1.03, 1.62]54% [33%, 70%]85%100%+0.09+0.342026-08-05 → 2026-08-30
tmin00Zbilinear90d26 1 QC1.09 [0.89, 1.41]0.79-0.72 [-1.31, -0.05]1.27 [1.01, 1.66]54% [31%, 71%]85%100%+0.09+0.342026-08-05 → 2026-08-30
tmin00Zbilinear365d26 1 QC1.09 [0.88, 1.37]0.79-0.72 [-1.28, 0.08]1.27 [0.97, 1.65]54% [31%, 73%]85%100%+0.09+0.342026-08-05 → 2026-08-30
tmin00Zbilinearall26 1 QC1.09 [0.86, 1.43]0.79-0.72 [-1.31, 0.04]1.27 [0.96, 1.71]54% [30%, 72%]85%100%+0.09+0.342026-08-05 → 2026-08-30
tmin00Znearest30d26 1 QC1.04 [0.79, 1.40]0.73-0.89 [-1.36, -0.41]1.28 [0.97, 1.69]50% [33%, 68%]88%100%+0.13+0.392026-08-05 → 2026-08-30
tmin00Znearest90d26 1 QC1.04 [0.77, 1.47]0.73-0.89 [-1.45, -0.37]1.28 [0.95, 1.76]50% [31%, 68%]88%100%+0.13+0.392026-08-05 → 2026-08-30
tmin00Znearest365d26 1 QC1.04 [0.76, 1.42]0.73-0.89 [-1.42, -0.31]1.28 [0.93, 1.75]50% [31%, 69%]88%100%+0.13+0.392026-08-05 → 2026-08-30
tmin00Znearestall26 1 QC1.04 [0.76, 1.49]0.73-0.89 [-1.47, -0.35]1.28 [0.94, 1.82]50% [30%, 69%]88%100%+0.13+0.392026-08-05 → 2026-08-30
tmin12Zbilinear30d26 1 QC1.44 [1.04, 1.88]0.93-1.12 [-1.86, -0.23]1.71 [1.32, 2.12]31% [8%, 57%]69%92%-0.21+0.222026-08-05 → 2026-08-30
tmin12Zbilinear90d26 1 QC1.44 [1.03, 1.95]0.93-1.12 [-1.93, -0.12]1.71 [1.28, 2.17]31% [6%, 60%]69%92%-0.21+0.222026-08-05 → 2026-08-30
tmin12Zbilinear365d26 1 QC1.44 [0.97, 1.92]0.93-1.12 [-1.92, -0.01]1.71 [1.21, 2.16]31% [5%, 64%]69%92%-0.21+0.222026-08-05 → 2026-08-30
tmin12Zbilinearall26 1 QC1.44 [0.94, 1.94]0.93-1.12 [-1.93, -0.09]1.71 [1.19, 2.17]31% [5%, 62%]69%92%-0.21+0.222026-08-05 → 2026-08-30
tmin12Znearest30d26 1 QC1.48 [1.08, 1.93]0.83-1.31 [-1.90, -0.64]1.71 [1.30, 2.19]35% [18%, 52%]65%96%-0.24+0.312026-08-05 → 2026-08-30
tmin12Znearest90d26 1 QC1.48 [1.07, 2.08]0.83-1.31 [-2.06, -0.57]1.71 [1.30, 2.30]35% [17%, 53%]65%96%-0.24+0.312026-08-05 → 2026-08-30
tmin12Znearest365d26 1 QC1.48 [1.02, 2.03]0.83-1.31 [-2.03, -0.46]1.71 [1.26, 2.26]35% [15%, 57%]65%96%-0.24+0.312026-08-05 → 2026-08-30
tmin12Znearestall26 1 QC1.48 [1.04, 2.09]0.83-1.31 [-2.09, -0.51]1.71 [1.27, 2.28]35% [14%, 54%]65%96%-0.24+0.312026-08-05 → 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 KSAN, lead day 4, 00Z bilinear tmax+10+50-5-102026-08-05: -3.73 °F2026-08-06: -4.7 °F2026-08-07: -4.2 °F2026-08-08: -3.21 °F2026-08-09: -5.13 °F2026-08-10: -4.87 °F2026-08-11: -4.36 °F2026-08-12: -4.13 °F2026-08-13: -2.09 °F2026-08-14: -2.75 °F2026-08-15: -1.85 °F2026-08-16: -0.18 °F2026-08-17: -1.45 °F2026-08-18: -0.29 °F2026-08-19: -0.65 °F2026-08-20: -4.52 °F2026-08-21: -5.25 °F2026-08-22: -5.15 °F2026-08-23: -7.23 °F2026-08-24: -3.44 °F2026-08-25: -3.82 °F2026-08-26: -7.39 °F2026-08-27: -1.47 °F2026-08-28: -1.01 °F2026-08-29: -5.96 °F2026-08-30: -1.62 °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
2026-08-30-1.62
2026-08-29-5.96
2026-08-28-1.01
2026-08-27-1.47
2026-08-26-7.39
2026-08-25-3.82
2026-08-24-3.44
2026-08-23-7.23
2026-08-22-5.15
2026-08-21-5.25
2026-08-20-4.52
2026-08-19-0.65
2026-08-18-0.29
2026-08-17-1.45
2026-08-16-0.18
2026-08-15-1.85
2026-08-14-2.75
2026-08-13-2.09
2026-08-12-4.13
2026-08-11-4.36
2026-08-10-4.87
2026-08-09-5.13
2026-08-08-3.21
2026-08-07-4.20
2026-08-06-4.70
2026-08-05-3.73

Error distribution

Distribution of the signed daily error in °F for ECMWF AIFS Single at KSAN, lead day 4-10 to -9 °F: 0 days-9 to -8 °F: 0 days-8 to -7 °F: 2 days-7 to -6 °F: 0 days-6 to -5 °F: 4 days-5 to -4 °F: 6 days-4 to -3 °F: 4 days-3 to -2 °F: 2 days-2 to -1 °F: 5 days-1 to 0 °F: 3 days0 to 1 °F: 0 days1 to 2 °F: 0 days2 to 3 °F: 0 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| 3.77 · P90 |e| 5.6 °F-100+10 °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
-10.00-9.000
-9.00-8.000
-8.00-7.002
-7.00-6.000
-6.00-5.004
-5.00-4.006
-4.00-3.004
-3.00-2.002
-2.00-1.005
-1.00+0.003
+0.00+1.000
+1.00+2.000
+2.00+3.000
+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
2026-08263.48 -3.48

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 +0.39 [-0.44, 1.20] no
GraphCast (IFS init) 25 -2.25 [-3.14, -1.45] yes
ECMWF IFS HRES 20 -2.37 [-3.33, -1.32] yes
Persistence (baseline) 26 +0.48 [-0.87, 1.76] no

Cite this page

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

LongCastCheck (2026). Station-level verification of raw weather-model 2 m temperature forecasts: KSAN (San Diego Lindbergh), 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/KSAN/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