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

Trenton Mercer · ECMWF AIFS Single · lead day 2

KTTN · aifs_single · lead 2

Target day = initialization date + 2 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
tmax00Zbilinear30d28 1 QC2.34 [1.96, 2.79]2.18+0.54 [-1.01, 2.00]3.00 [2.56, 3.50]25% [10%, 41%]61%68%+0.15+0.172026-08-03 → 2026-08-30
tmax00Zbilinear90d28 1 QC2.34 [1.96, 2.87]2.18+0.54 [-1.40, 2.09]3.00 [2.53, 3.55]25% [12%, 42%]61%68%+0.15+0.172026-08-03 → 2026-08-30
tmax00Zbilinear365d28 1 QC2.34 [1.94, 2.88]2.18+0.54 [-1.45, 2.31]3.00 [2.53, 3.54]25% [10%, 43%]61%68%+0.15+0.172026-08-03 → 2026-08-30
tmax00Zbilinearall28 1 QC2.34 [1.94, 2.87]2.18+0.54 [-1.48, 2.19]3.00 [2.52, 3.57]25% [10%, 43%]61%68%+0.15+0.172026-08-03 → 2026-08-30
tmax00Znearest30d28 1 QC2.51 [2.09, 3.01]2.22+0.84 [-0.74, 2.32]3.13 [2.67, 3.63]21% [7%, 38%]46%71%+0.09+0.162026-08-03 → 2026-08-30
tmax00Znearest90d28 1 QC2.51 [2.09, 3.05]2.22+0.84 [-1.12, 2.41]3.13 [2.68, 3.66]21% [7%, 40%]46%71%+0.09+0.162026-08-03 → 2026-08-30
tmax00Znearest365d28 1 QC2.51 [2.07, 3.09]2.22+0.84 [-1.20, 2.66]3.13 [2.65, 3.67]21% [5%, 40%]46%71%+0.09+0.162026-08-03 → 2026-08-30
tmax00Znearestall28 1 QC2.51 [2.05, 3.06]2.22+0.84 [-1.26, 2.51]3.13 [2.66, 3.66]21% [6%, 40%]46%71%+0.09+0.162026-08-03 → 2026-08-30
tmax12Zbilinear30d28 1 QC2.05 [1.65, 2.53]1.97+0.18 [-1.07, 1.31]2.75 [2.06, 3.46]32% [20%, 46%]71%79%+0.26+0.252026-08-03 → 2026-08-30
tmax12Zbilinear90d28 1 QC2.05 [1.61, 2.59]1.97+0.18 [-1.30, 1.40]2.75 [1.94, 3.55]32% [19%, 47%]71%79%+0.26+0.252026-08-03 → 2026-08-30
tmax12Zbilinear365d28 1 QC2.05 [1.50, 2.61]1.97+0.18 [-1.43, 1.49]2.75 [1.77, 3.61]32% [18%, 48%]71%79%+0.26+0.252026-08-03 → 2026-08-30
tmax12Zbilinearall28 1 QC2.05 [1.58, 2.69]1.97+0.18 [-1.48, 1.53]2.75 [1.91, 3.70]32% [18%, 47%]71%79%+0.26+0.252026-08-03 → 2026-08-30
tmax12Znearest30d28 1 QC2.18 [1.79, 2.61]1.98+0.48 [-0.81, 1.66]2.81 [2.21, 3.44]32% [20%, 46%]57%79%+0.21+0.252026-08-03 → 2026-08-30
tmax12Znearest90d28 1 QC2.18 [1.71, 2.66]1.98+0.48 [-1.03, 1.73]2.81 [2.14, 3.49]32% [19%, 47%]57%79%+0.21+0.252026-08-03 → 2026-08-30
tmax12Znearest365d28 1 QC2.18 [1.65, 2.67]1.98+0.48 [-1.16, 1.79]2.81 [1.95, 3.55]32% [18%, 48%]57%79%+0.21+0.252026-08-03 → 2026-08-30
tmax12Znearestall28 1 QC2.18 [1.70, 2.71]1.98+0.48 [-1.20, 1.84]2.81 [2.06, 3.62]32% [18%, 47%]57%79%+0.21+0.252026-08-03 → 2026-08-30
tmin00Zbilinear30d28 1 QC4.43 [3.83, 5.05]1.57+4.43 [3.83, 5.05]4.81 [4.25, 5.38]7% [0%, 15%]7%29%-0.14+0.602026-08-03 → 2026-08-30
tmin00Zbilinear90d28 1 QC4.43 [3.83, 5.13]1.57+4.43 [3.83, 5.13]4.81 [4.26, 5.44]7% [0%, 17%]7%29%-0.14+0.602026-08-03 → 2026-08-30
tmin00Zbilinear365d28 1 QC4.43 [3.80, 5.24]1.57+4.43 [3.80, 5.24]4.81 [4.21, 5.58]7% [0%, 16%]7%29%-0.14+0.602026-08-03 → 2026-08-30
tmin00Zbilinearall28 1 QC4.43 [3.85, 5.17]1.57+4.43 [3.85, 5.17]4.81 [4.26, 5.56]7% [0%, 16%]7%29%-0.14+0.602026-08-03 → 2026-08-30
tmin00Znearest30d28 1 QC4.68 [4.10, 5.28]1.58+4.68 [4.10, 5.28]5.04 [4.50, 5.59]4% [0%, 10%]7%25%-0.20+0.592026-08-03 → 2026-08-30
tmin00Znearest90d28 1 QC4.68 [4.11, 5.35]1.58+4.68 [4.11, 5.35]5.04 [4.52, 5.66]4% [0%, 11%]7%25%-0.20+0.592026-08-03 → 2026-08-30
tmin00Znearest365d28 1 QC4.68 [4.08, 5.47]1.58+4.68 [4.08, 5.47]5.04 [4.46, 5.78]4% [0%, 11%]7%25%-0.20+0.592026-08-03 → 2026-08-30
tmin00Znearestall28 1 QC4.68 [4.11, 5.41]1.58+4.68 [4.11, 5.41]5.04 [4.50, 5.79]4% [0%, 11%]7%25%-0.20+0.592026-08-03 → 2026-08-30
tmin12Zbilinear30d28 1 QC4.49 [4.01, 5.01]1.41+4.49 [4.01, 5.01]4.80 [4.31, 5.29]0% [0%, 0%]11%18%-0.15+0.642026-08-03 → 2026-08-30
tmin12Zbilinear90d28 1 QC4.49 [4.00, 5.07]1.41+4.49 [4.00, 5.07]4.80 [4.32, 5.33]0% [0%, 0%]11%18%-0.15+0.642026-08-03 → 2026-08-30
tmin12Zbilinear365d28 1 QC4.49 [3.98, 5.15]1.41+4.49 [3.98, 5.15]4.80 [4.30, 5.37]0% [0%, 0%]11%18%-0.15+0.642026-08-03 → 2026-08-30
tmin12Zbilinearall28 1 QC4.49 [3.99, 5.10]1.41+4.49 [3.99, 5.10]4.80 [4.28, 5.45]0% [0%, 0%]11%18%-0.15+0.642026-08-03 → 2026-08-30
tmin12Znearest30d28 1 QC4.75 [4.29, 5.25]1.41+4.75 [4.29, 5.25]5.04 [4.57, 5.52]0% [0%, 0%]7%11%-0.22+0.642026-08-03 → 2026-08-30
tmin12Znearest90d28 1 QC4.75 [4.29, 5.30]1.41+4.75 [4.29, 5.30]5.04 [4.60, 5.56]0% [0%, 0%]7%11%-0.22+0.642026-08-03 → 2026-08-30
tmin12Znearest365d28 1 QC4.75 [4.27, 5.37]1.41+4.75 [4.27, 5.37]5.04 [4.56, 5.60]0% [0%, 0%]7%11%-0.22+0.642026-08-03 → 2026-08-30
tmin12Znearestall28 1 QC4.75 [4.28, 5.33]1.41+4.75 [4.28, 5.33]5.04 [4.54, 5.69]0% [0%, 0%]7%11%-0.22+0.642026-08-03 → 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 2, 00Z bilinear tmax+10+50-5-102026-08-03: -5.43 °F2026-08-04: -0.18 °F2026-08-05: -3 °F2026-08-06: -0.5 °F2026-08-07: -4.03 °F2026-08-08: -0.06 °F2026-08-09: +1.87 °F2026-08-10: +1.56 °F2026-08-11: +4.98 °F2026-08-12: +1.19 °F2026-08-13: +2.04 °F2026-08-14: +1.73 °F2026-08-15: +1.42 °F2026-08-16: +6.53 °F2026-08-17: +3.22 °F2026-08-18: +1.95 °F2026-08-19: +0.71 °F2026-08-20: -3.34 °F2026-08-21: -1.77 °F2026-08-22: -6.75 °F2026-08-23: +0.59 °F2026-08-24: -0.08 °F2026-08-25: +1.52 °F2026-08-26: +1.36 °F2026-08-27: +1.72 °F2026-08-28: +2.13 °F2026-08-29: +5.15 °F2026-08-30: +0.65 °F2026-08-032026-08-30°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 (28 days, newest first) · download CSV
Climatological dayError °F
2026-08-30+0.65
2026-08-29+5.15
2026-08-28+2.13
2026-08-27+1.72
2026-08-26+1.36
2026-08-25+1.52
2026-08-24-0.08
2026-08-23+0.59
2026-08-22-6.75
2026-08-21-1.77
2026-08-20-3.34
2026-08-19+0.71
2026-08-18+1.95
2026-08-17+3.22
2026-08-16+6.53
2026-08-15+1.42
2026-08-14+1.73
2026-08-13+2.04
2026-08-12+1.19
2026-08-11+4.98
2026-08-10+1.56
2026-08-09+1.87
2026-08-08-0.06
2026-08-07-4.03
2026-08-06-0.50
2026-08-05-3.00
2026-08-04-0.18
2026-08-03-5.43

Error distribution

Distribution of the signed daily error in °F for ECMWF AIFS Single at KTTN, lead day 2-10 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: 0 days-2 to -1 °F: 1 day-1 to 0 °F: 4 days0 to 1 °F: 3 days1 to 2 °F: 9 days2 to 3 °F: 2 days3 to 4 °F: 1 day4 to 5 °F: 1 day5 to 6 °F: 1 day6 to 7 °F: 1 day7 to 8 °F: 0 days8 to 9 °F: 0 days9 to 10 °F: 0 daysdashed: P50 |e| 1.75 · P90 |e| 5.23 °F-100+10 °Fn = 28 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
-3.00-2.000
-2.00-1.001
-1.00+0.004
+0.00+1.003
+1.00+2.009
+2.00+3.002
+3.00+4.001
+4.00+5.001
+5.00+6.001
+6.00+7.001
+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
2026-08282.34 +0.54

Availability

ModelScored period DaysCoverage
ECMWF AIFS Single2026-08-03 → 2026-08-30 28
ECMWF AIFS Single2026-08-03 → 2026-08-30 28
ECMWF AIFS Single2026-08-03 → 2026-08-30 28
ECMWF AIFS Single2026-08-03 → 2026-08-30 28

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 (IFS init) 1 +0.33 [0.33, 0.33] yes
FourCastNet v2 (IFS init) 1 -0.42 [-0.42, -0.42] yes
NCEP GFS 28 -0.74 [-1.82, -0.05] yes
GraphCast (IFS init) 26 -0.34 [-1.37, 0.51] no
ECMWF IFS HRES 22 +0.06 [-0.36, 0.60] no
Pangu-Weather (IFS init) 1 -1.46 [-1.46, -1.46] yes
Persistence (baseline) 28 -0.41 [-1.28, 0.39] no

Cite this page

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

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

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