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

Trenton Mercer · ECMWF AIFS Single · lead day 0

KTTN · aifs_single · 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, 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
tmax00Zbilinear30d30 1 QC1.83 [1.54, 2.16]1.57+0.70 [-0.31, 1.76]2.11 [1.77, 2.45]20% [10%, 33%]57%87%——2026-08-01 → 2026-08-30
tmax00Zbilinear90d30 1 QC1.83 [1.51, 2.14]1.57+0.70 [-0.58, 1.83]2.11 [1.71, 2.45]20% [6%, 38%]57%87%——2026-08-01 → 2026-08-30
tmax00Zbilinear365d30 1 QC1.83 [1.49, 2.22]1.57+0.70 [-0.60, 1.97]2.11 [1.67, 2.49]20% [4%, 39%]57%87%——2026-08-01 → 2026-08-30
tmax00Zbilinearall30 1 QC1.83 [1.50, 2.17]1.57+0.70 [-0.60, 1.86]2.11 [1.69, 2.51]20% [6%, 39%]57%87%——2026-08-01 → 2026-08-30
tmax00Znearest30d30 1 QC2.02 [1.66, 2.47]1.61+1.03 [-0.00, 2.12]2.29 [1.90, 2.71]17% [3%, 33%]50%80%——2026-08-01 → 2026-08-30
tmax00Znearest90d30 1 QC2.02 [1.61, 2.44]1.61+1.03 [-0.24, 2.19]2.29 [1.82, 2.70]17% [0%, 38%]50%80%——2026-08-01 → 2026-08-30
tmax00Znearest365d30 1 QC2.02 [1.57, 2.55]1.61+1.03 [-0.29, 2.34]2.29 [1.80, 2.76]17% [0%, 38%]50%80%——2026-08-01 → 2026-08-30
tmax00Znearestall30 1 QC2.02 [1.61, 2.49]1.61+1.03 [-0.28, 2.20]2.29 [1.81, 2.74]17% [0%, 40%]50%80%——2026-08-01 → 2026-08-30
tmin00Zbilinear30d30 1 QC3.66 [3.24, 4.12]1.41+3.66 [3.24, 4.12]4.04 [3.57, 4.53]7% [0%, 17%]17%33%——2026-08-01 → 2026-08-30
tmin00Zbilinear90d30 1 QC3.66 [3.16, 4.14]1.41+3.66 [3.16, 4.14]4.04 [3.45, 4.58]7% [0%, 18%]17%33%——2026-08-01 → 2026-08-30
tmin00Zbilinear365d30 1 QC3.66 [3.16, 4.20]1.41+3.66 [3.16, 4.20]4.04 [3.44, 4.60]7% [0%, 18%]17%33%——2026-08-01 → 2026-08-30
tmin00Zbilinearall30 1 QC3.66 [3.15, 4.18]1.41+3.66 [3.15, 4.18]4.04 [3.47, 4.57]7% [0%, 18%]17%33%——2026-08-01 → 2026-08-30
tmin00Znearest30d30 1 QC3.91 [3.50, 4.36]1.42+3.91 [3.50, 4.36]4.28 [3.80, 4.75]7% [0%, 17%]13%27%——2026-08-01 → 2026-08-30
tmin00Znearest90d30 1 QC3.91 [3.43, 4.37]1.42+3.91 [3.43, 4.37]4.28 [3.70, 4.80]7% [0%, 18%]13%27%——2026-08-01 → 2026-08-30
tmin00Znearest365d30 1 QC3.91 [3.41, 4.43]1.42+3.91 [3.41, 4.43]4.28 [3.68, 4.83]7% [0%, 18%]13%27%——2026-08-01 → 2026-08-30
tmin00Znearestall30 1 QC3.91 [3.42, 4.41]1.42+3.91 [3.42, 4.41]4.28 [3.72, 4.81]7% [0%, 18%]13%27%——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 ECMWF AIFS Single at KTTN, lead day 0, 00Z bilinear tmax+5+2.50-2.5-52026-08-01: -0.52 °F2026-08-02: +0.25 °F2026-08-03: -4.92 °F2026-08-04: +1.11 °F2026-08-05: -3.01 °F2026-08-06: +0.39 °F2026-08-07: -1.33 °F2026-08-08: +0.99 °F2026-08-09: +2.01 °F2026-08-10: +1.02 °F2026-08-11: +1.38 °F2026-08-12: +3.05 °F2026-08-13: +2.97 °F2026-08-14: +3.85 °F2026-08-15: +2.73 °F2026-08-16: +2.48 °F2026-08-17: +1.13 °F2026-08-18: +0.4 °F2026-08-19: +1.17 °F2026-08-20: -1.68 °F2026-08-21: -2.04 °F2026-08-22: -2.21 °F2026-08-23: +0.99 °F2026-08-24: +1.19 °F2026-08-25: +2.94 °F2026-08-26: +2.01 °F2026-08-27: +2.13 °F2026-08-28: -1.22 °F2026-08-29: +1.93 °F2026-08-30: +1.77 °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+1.77
2026-08-29+1.93
2026-08-28-1.22
2026-08-27+2.13
2026-08-26+2.01
2026-08-25+2.94
2026-08-24+1.19
2026-08-23+0.99
2026-08-22-2.21
2026-08-21-2.04
2026-08-20-1.68
2026-08-19+1.17
2026-08-18+0.40
2026-08-17+1.13
2026-08-16+2.48
2026-08-15+2.73
2026-08-14+3.85
2026-08-13+2.97
2026-08-12+3.05
2026-08-11+1.38
2026-08-10+1.02
2026-08-09+2.01
2026-08-08+0.99
2026-08-07-1.33
2026-08-06+0.39
2026-08-05-3.01
2026-08-04+1.11
2026-08-03-4.92
2026-08-02+0.25
2026-08-01-0.52

Error distribution

Distribution of the signed daily error in °F for ECMWF AIFS Single at KTTN, lead day 0-5 to -4.5 °F: 1 day-4.5 to -4 °F: 0 days-4 to -3.5 °F: 0 days-3.5 to -3 °F: 1 day-3 to -2.5 °F: 0 days-2.5 to -2 °F: 2 days-2 to -1.5 °F: 1 day-1.5 to -1 °F: 2 days-1 to -0.5 °F: 1 day-0.5 to 0 °F: 0 days0 to 0.5 °F: 3 days0.5 to 1 °F: 2 days1 to 1.5 °F: 6 days1.5 to 2 °F: 2 days2 to 2.5 °F: 4 days2.5 to 3 °F: 3 days3 to 3.5 °F: 1 day3.5 to 4 °F: 1 day4 to 4.5 °F: 0 days4.5 to 5 °F: 0 daysdashed: P50 |e| 1.72 · P90 |e| 3.02 °F-50+5 °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
-5.00-4.501
-4.50-4.000
-4.00-3.500
-3.50-3.001
-3.00-2.500
-2.50-2.002
-2.00-1.501
-1.50-1.002
-1.00-0.501
-0.50+0.000
+0.00+0.503
+0.50+1.002
+1.00+1.506
+1.50+2.002
+2.00+2.504
+2.50+3.003
+3.00+3.501
+3.50+4.001
+4.00+4.500
+4.50+5.000

Month by month

00Z bilinear daily maximum, newest first.

Monthn MAE °FBias °F
2026-08301.83 +0.70

Availability

ModelScored period DaysCoverage
ECMWF AIFS Single2026-08-01 → 2026-08-30 30
ECMWF AIFS Single2026-08-01 → 2026-08-30 30

Compared with other models

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

Other modelCommon days MAE difference °FDistinguishable
Aurora (GFS init) 2 +0.23 [-0.78, 1.24] no
Aurora (IFS init) 3 +0.68 [-0.61, 1.67] no
FourCastNet v2 (GFS init) 2 -0.75 [-2.00, 0.50] no
FourCastNet v2 (IFS init) 3 -1.08 [-2.61, -0.32] yes
NCEP GFS 30 -0.05 [-0.62, 0.45] no
GraphCast (GFS init) 2 +0.09 [-0.85, 1.03] no
GraphCast (IFS init) 28 -0.26 [-1.59, 0.97] no
ECMWF IFS HRES 24 +0.28 [-0.07, 0.51] no
Pangu-Weather (GFS init) 2 -0.40 [-0.90, 0.10] no
Pangu-Weather (IFS init) 3 +0.05 [-0.50, 1.13] no

Cite this page

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

LongCastCheck (2026). Station-level verification of raw weather-model 2 m temperature forecasts: KTTN (Trenton Mercer), model aifs_single, 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/KTTN/model/aifs_single/lead/0/

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