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

Trenton Mercer · ECMWF AIFS Single · lead day 3

KTTN · aifs_single · 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, 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
tmax00Zbilinear30d27 1 QC1.63 [1.12, 2.19]1.42+0.80 [-0.43, 1.58]2.20 [1.54, 2.76]44% [25%, 63%]70%78%+0.52+0.572026-08-04 → 2026-08-30
tmax00Zbilinear90d27 1 QC1.63 [1.07, 2.31]1.42+0.80 [-0.70, 1.71]2.20 [1.48, 2.90]44% [22%, 64%]70%78%+0.52+0.572026-08-04 → 2026-08-30
tmax00Zbilinear365d27 1 QC1.63 [1.07, 2.29]1.42+0.80 [-0.60, 1.82]2.20 [1.47, 2.83]44% [20%, 65%]70%78%+0.52+0.572026-08-04 → 2026-08-30
tmax00Zbilinearall27 1 QC1.63 [1.03, 2.31]1.42+0.80 [-0.63, 1.73]2.20 [1.48, 2.91]44% [21%, 68%]70%78%+0.52+0.572026-08-04 → 2026-08-30
tmax00Znearest30d27 1 QC1.85 [1.33, 2.35]1.44+1.12 [-0.09, 1.93]2.35 [1.71, 2.87]41% [23%, 60%]70%74%+0.45+0.562026-08-04 → 2026-08-30
tmax00Znearest90d27 1 QC1.85 [1.29, 2.49]1.44+1.12 [-0.33, 2.03]2.35 [1.65, 2.99]41% [21%, 62%]70%74%+0.45+0.562026-08-04 → 2026-08-30
tmax00Znearest365d27 1 QC1.85 [1.26, 2.51]1.44+1.12 [-0.32, 2.18]2.35 [1.63, 2.97]41% [20%, 64%]70%74%+0.45+0.562026-08-04 → 2026-08-30
tmax00Znearestall27 1 QC1.85 [1.23, 2.48]1.44+1.12 [-0.32, 2.07]2.35 [1.58, 2.96]41% [20%, 67%]70%74%+0.45+0.562026-08-04 → 2026-08-30
tmax12Zbilinear30d27 1 QC1.95 [1.62, 2.30]1.89+0.52 [-0.62, 1.65]2.61 [2.10, 3.01]41% [28%, 54%]67%78%+0.42+0.432026-08-04 → 2026-08-30
tmax12Zbilinear90d27 1 QC1.95 [1.59, 2.35]1.89+0.52 [-0.91, 1.88]2.61 [2.07, 3.08]41% [26%, 56%]67%78%+0.42+0.432026-08-04 → 2026-08-30
tmax12Zbilinear365d27 1 QC1.95 [1.57, 2.46]1.89+0.52 [-1.00, 1.99]2.61 [2.02, 3.12]41% [23%, 57%]67%78%+0.42+0.432026-08-04 → 2026-08-30
tmax12Zbilinearall27 1 QC1.95 [1.58, 2.35]1.89+0.52 [-1.03, 1.92]2.61 [2.03, 3.06]41% [25%, 57%]67%78%+0.42+0.432026-08-04 → 2026-08-30
tmax12Znearest30d27 1 QC2.08 [1.66, 2.50]1.93+0.83 [-0.35, 1.96]2.73 [2.23, 3.12]37% [22%, 54%]59%78%+0.38+0.412026-08-04 → 2026-08-30
tmax12Znearest90d27 1 QC2.08 [1.61, 2.55]1.93+0.83 [-0.65, 2.19]2.73 [2.13, 3.16]37% [20%, 55%]59%78%+0.38+0.412026-08-04 → 2026-08-30
tmax12Znearest365d27 1 QC2.08 [1.55, 2.63]1.93+0.83 [-0.73, 2.34]2.73 [2.09, 3.24]37% [16%, 57%]59%78%+0.38+0.412026-08-04 → 2026-08-30
tmax12Znearestall27 1 QC2.08 [1.57, 2.58]1.93+0.83 [-0.81, 2.27]2.73 [2.11, 3.15]37% [17%, 57%]59%78%+0.38+0.412026-08-04 → 2026-08-30
tmin00Zbilinear30d27 1 QC4.54 [3.98, 5.16]1.84+4.49 [3.87, 5.16]4.98 [4.43, 5.55]4% [0%, 11%]11%22%-0.10+0.532026-08-04 → 2026-08-30
tmin00Zbilinear90d27 1 QC4.54 [3.94, 5.30]1.84+4.49 [3.86, 5.30]4.98 [4.42, 5.71]4% [0%, 11%]11%22%-0.10+0.532026-08-04 → 2026-08-30
tmin00Zbilinear365d27 1 QC4.54 [3.95, 5.40]1.84+4.49 [3.85, 5.40]4.98 [4.40, 5.76]4% [0%, 11%]11%22%-0.10+0.532026-08-04 → 2026-08-30
tmin00Zbilinearall27 1 QC4.54 [3.97, 5.31]1.84+4.49 [3.85, 5.30]4.98 [4.41, 5.71]4% [0%, 11%]11%22%-0.10+0.532026-08-04 → 2026-08-30
tmin00Znearest30d27 1 QC4.78 [4.23, 5.42]1.85+4.75 [4.17, 5.42]5.22 [4.68, 5.79]4% [0%, 11%]7%22%-0.16+0.532026-08-04 → 2026-08-30
tmin00Znearest90d27 1 QC4.78 [4.18, 5.55]1.85+4.75 [4.14, 5.55]5.22 [4.67, 5.92]4% [0%, 11%]7%22%-0.16+0.532026-08-04 → 2026-08-30
tmin00Znearest365d27 1 QC4.78 [4.20, 5.66]1.85+4.75 [4.14, 5.66]5.22 [4.66, 5.98]4% [0%, 11%]7%22%-0.16+0.532026-08-04 → 2026-08-30
tmin00Znearestall27 1 QC4.78 [4.21, 5.57]1.85+4.75 [4.13, 5.53]5.22 [4.67, 5.95]4% [0%, 11%]7%22%-0.16+0.532026-08-04 → 2026-08-30
tmin12Zbilinear30d27 1 QC4.52 [3.79, 5.25]1.59+4.52 [3.79, 5.25]4.92 [4.20, 5.60]4% [0%, 11%]7%19%-0.10+0.602026-08-04 → 2026-08-30
tmin12Zbilinear90d27 1 QC4.52 [3.69, 5.41]1.59+4.52 [3.69, 5.41]4.92 [4.09, 5.74]4% [0%, 11%]7%19%-0.10+0.602026-08-04 → 2026-08-30
tmin12Zbilinear365d27 1 QC4.52 [3.70, 5.53]1.59+4.52 [3.70, 5.53]4.92 [4.11, 5.88]4% [0%, 11%]7%19%-0.10+0.602026-08-04 → 2026-08-30
tmin12Zbilinearall27 1 QC4.52 [3.69, 5.38]1.59+4.52 [3.69, 5.38]4.92 [4.10, 5.73]4% [0%, 11%]7%19%-0.10+0.602026-08-04 → 2026-08-30
tmin12Znearest30d27 1 QC4.77 [4.05, 5.49]1.58+4.77 [4.05, 5.49]5.16 [4.43, 5.81]4% [0%, 11%]7%15%-0.16+0.602026-08-04 → 2026-08-30
tmin12Znearest90d27 1 QC4.77 [3.97, 5.62]1.58+4.77 [3.97, 5.62]5.16 [4.35, 5.95]4% [0%, 11%]7%15%-0.16+0.602026-08-04 → 2026-08-30
tmin12Znearest365d27 1 QC4.77 [4.00, 5.76]1.58+4.77 [4.00, 5.76]5.16 [4.37, 6.10]4% [0%, 11%]7%15%-0.16+0.602026-08-04 → 2026-08-30
tmin12Znearestall27 1 QC4.77 [3.98, 5.62]1.58+4.77 [3.98, 5.62]5.16 [4.38, 5.95]4% [0%, 11%]7%15%-0.16+0.602026-08-04 → 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 ECMWF AIFS Single at KTTN, lead day 3, 00Z bilinear tmax+10+50-5-102026-08-04: +0.23 °F2026-08-05: -4.18 °F2026-08-06: -1.53 °F2026-08-07: -4.38 °F2026-08-08: +0.27 °F2026-08-09: +0.3 °F2026-08-10: +2.83 °F2026-08-11: +5.31 °F2026-08-12: +1.38 °F2026-08-13: +1.55 °F2026-08-14: +0.77 °F2026-08-15: +0.16 °F2026-08-16: +1.14 °F2026-08-17: +3.79 °F2026-08-18: +0.67 °F2026-08-19: +0.05 °F2026-08-20: +2.36 °F2026-08-21: +0.91 °F2026-08-22: +0.67 °F2026-08-23: +0.43 °F2026-08-24: +0.03 °F2026-08-25: +1.61 °F2026-08-26: +0.44 °F2026-08-27: -1.07 °F2026-08-28: +1.33 °F2026-08-29: +3.39 °F2026-08-30: +3.14 °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+3.14
2026-08-29+3.39
2026-08-28+1.33
2026-08-27-1.07
2026-08-26+0.44
2026-08-25+1.61
2026-08-24+0.03
2026-08-23+0.43
2026-08-22+0.67
2026-08-21+0.91
2026-08-20+2.36
2026-08-19+0.05
2026-08-18+0.67
2026-08-17+3.79
2026-08-16+1.14
2026-08-15+0.16
2026-08-14+0.77
2026-08-13+1.55
2026-08-12+1.38
2026-08-11+5.31
2026-08-10+2.83
2026-08-09+0.30
2026-08-08+0.27
2026-08-07-4.38
2026-08-06-1.53
2026-08-05-4.18
2026-08-04+0.23

Error distribution

Distribution of the signed daily error in °F for ECMWF AIFS Single at KTTN, 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: 0 days-6 to -5 °F: 0 days-5 to -4 °F: 2 days-4 to -3 °F: 0 days-3 to -2 °F: 0 days-2 to -1 °F: 2 days-1 to 0 °F: 0 days0 to 1 °F: 12 days1 to 2 °F: 5 days2 to 3 °F: 2 days3 to 4 °F: 3 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| 1.14 · P90 |e| 3.95 °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
-7.00-6.000
-6.00-5.000
-5.00-4.002
-4.00-3.000
-3.00-2.000
-2.00-1.002
-1.00+0.000
+0.00+1.0012
+1.00+2.005
+2.00+3.002
+3.00+4.003
+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
2026-08271.63 +0.80

Availability

ModelScored period DaysCoverage
ECMWF AIFS Single2026-08-04 → 2026-08-30 27
ECMWF AIFS Single2026-08-04 → 2026-08-30 27
ECMWF AIFS Single2026-08-04 → 2026-08-30 27
ECMWF AIFS Single2026-08-04 → 2026-08-30 27

Compared with other models

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

Other modelCommon days MAE difference °FDistinguishable
NCEP GFS 27 -0.90 [-1.61, -0.25] yes
GraphCast (IFS init) 25 -0.97 [-1.98, -0.37] yes
ECMWF IFS HRES 22 -0.84 [-1.91, 0.32] no
Persistence (baseline) 27 -1.74 [-2.40, -1.04] yes

Cite this page

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

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