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

Trenton Mercer · ECMWF AIFS Single · lead day 8

KTTN · aifs_single · lead 8

Target day = initialization date + 8 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
tmax00Zbilinear30d22 1 QC2.19 [1.57, 2.71]2.00-1.05 [-2.12, -0.00]2.83 [1.88, 3.59]27% [12%, 46%]50%77%+0.42+0.372026-08-09 → 2026-08-30
tmax00Zbilinear90d22 1 QC2.19 [1.42, 2.78]2.00-1.05 [-2.27, 0.08]2.83 [1.69, 3.71]27% [12%, 50%]50%77%+0.42+0.372026-08-09 → 2026-08-30
tmax00Zbilinear365d22 1 QC2.19 [1.41, 2.82]2.00-1.05 [-2.37, 0.14]2.83 [1.65, 3.78]27% [11%, 50%]50%77%+0.42+0.372026-08-09 → 2026-08-30
tmax00Zbilinearall22 1 QC2.19 [1.38, 2.82]2.00-1.05 [-2.35, 0.07]2.83 [1.57, 3.79]27% [7%, 50%]50%77%+0.42+0.372026-08-09 → 2026-08-30
tmax00Znearest30d22 1 QC2.14 [1.49, 2.64]2.02-0.76 [-1.82, 0.30]2.75 [1.76, 3.41]27% [12%, 46%]64%77%+0.43+0.362026-08-09 → 2026-08-30
tmax00Znearest90d22 1 QC2.14 [1.31, 2.71]2.02-0.76 [-1.93, 0.38]2.75 [1.54, 3.53]27% [12%, 50%]64%77%+0.43+0.362026-08-09 → 2026-08-30
tmax00Znearest365d22 1 QC2.14 [1.30, 2.72]2.02-0.76 [-2.04, 0.43]2.75 [1.49, 3.59]27% [11%, 50%]64%77%+0.43+0.362026-08-09 → 2026-08-30
tmax00Znearestall22 1 QC2.14 [1.26, 2.73]2.02-0.76 [-2.00, 0.37]2.75 [1.42, 3.59]27% [7%, 50%]64%77%+0.43+0.362026-08-09 → 2026-08-30
tmax12Zbilinear30d22 1 QC2.22 [1.58, 2.97]2.13-0.76 [-1.70, 0.08]2.72 [1.97, 3.40]27% [11%, 45%]55%64%+0.41+0.322026-08-09 → 2026-08-30
tmax12Zbilinear90d22 1 QC2.22 [1.36, 2.99]2.13-0.76 [-1.93, 0.27]2.72 [1.83, 3.44]27% [9%, 50%]55%64%+0.41+0.322026-08-09 → 2026-08-30
tmax12Zbilinear365d22 1 QC2.22 [1.43, 3.06]2.13-0.76 [-1.93, 0.29]2.72 [1.82, 3.49]27% [9%, 50%]55%64%+0.41+0.322026-08-09 → 2026-08-30
tmax12Zbilinearall22 1 QC2.22 [1.44, 2.93]2.13-0.76 [-2.00, 0.19]2.72 [1.85, 3.41]27% [9%, 50%]55%64%+0.41+0.322026-08-09 → 2026-08-30
tmax12Znearest30d22 1 QC2.16 [1.48, 2.92]2.16-0.46 [-1.42, 0.39]2.69 [1.90, 3.40]27% [11%, 45%]50%68%+0.43+0.312026-08-09 → 2026-08-30
tmax12Znearest90d22 1 QC2.16 [1.32, 2.98]2.16-0.46 [-1.63, 0.58]2.69 [1.81, 3.44]27% [9%, 50%]50%68%+0.43+0.312026-08-09 → 2026-08-30
tmax12Znearest365d22 1 QC2.16 [1.34, 3.11]2.16-0.46 [-1.64, 0.63]2.69 [1.80, 3.50]27% [9%, 50%]50%68%+0.43+0.312026-08-09 → 2026-08-30
tmax12Znearestall22 1 QC2.16 [1.34, 2.97]2.16-0.46 [-1.74, 0.50]2.69 [1.83, 3.41]27% [9%, 50%]50%68%+0.43+0.312026-08-09 → 2026-08-30
tmin00Zbilinear30d22 1 QC4.09 [3.35, 5.07]2.51+3.73 [2.76, 4.85]4.76 [4.04, 5.51]14% [0%, 27%]23%32%+0.14+0.322026-08-09 → 2026-08-30
tmin00Zbilinear90d22 1 QC4.09 [3.42, 5.30]2.51+3.73 [2.75, 5.14]4.76 [4.03, 5.66]14% [0%, 27%]23%32%+0.14+0.322026-08-09 → 2026-08-30
tmin00Zbilinear365d22 1 QC4.09 [3.38, 5.29]2.51+3.73 [2.70, 5.09]4.76 [3.99, 5.70]14% [0%, 29%]23%32%+0.14+0.322026-08-09 → 2026-08-30
tmin00Zbilinearall22 1 QC4.09 [3.30, 5.09]2.51+3.73 [2.66, 4.94]4.76 [3.93, 5.56]14% [0%, 29%]23%32%+0.14+0.322026-08-09 → 2026-08-30
tmin00Znearest30d22 1 QC4.27 [3.49, 5.31]2.51+3.98 [2.98, 5.14]4.96 [4.21, 5.74]14% [0%, 27%]27%32%+0.11+0.322026-08-09 → 2026-08-30
tmin00Znearest90d22 1 QC4.27 [3.56, 5.53]2.51+3.98 [2.96, 5.42]4.96 [4.18, 5.88]14% [0%, 27%]27%32%+0.11+0.322026-08-09 → 2026-08-30
tmin00Znearest365d22 1 QC4.27 [3.52, 5.51]2.51+3.98 [2.91, 5.36]4.96 [4.15, 5.91]14% [0%, 29%]27%32%+0.11+0.322026-08-09 → 2026-08-30
tmin00Znearestall22 1 QC4.27 [3.42, 5.32]2.51+3.98 [2.86, 5.19]4.96 [4.08, 5.79]14% [0%, 29%]27%32%+0.11+0.322026-08-09 → 2026-08-30
tmin12Zbilinear30d22 1 QC4.34 [3.55, 5.27]2.09+4.34 [3.55, 5.27]5.00 [4.21, 5.81]14% [0%, 26%]18%27%+0.09+0.442026-08-09 → 2026-08-30
tmin12Zbilinear90d22 1 QC4.34 [3.56, 5.52]2.09+4.34 [3.55, 5.52]5.00 [4.23, 5.99]14% [0%, 28%]18%27%+0.09+0.442026-08-09 → 2026-08-30
tmin12Zbilinear365d22 1 QC4.34 [3.50, 5.49]2.09+4.34 [3.49, 5.49]5.00 [4.21, 5.91]14% [0%, 29%]18%27%+0.09+0.442026-08-09 → 2026-08-30
tmin12Zbilinearall22 1 QC4.34 [3.42, 5.43]2.09+4.34 [3.41, 5.43]5.00 [3.98, 5.93]14% [0%, 29%]18%27%+0.09+0.442026-08-09 → 2026-08-30
tmin12Znearest30d22 1 QC4.60 [3.79, 5.56]2.10+4.60 [3.79, 5.56]5.23 [4.42, 6.06]9% [0%, 16%]18%27%+0.04+0.432026-08-09 → 2026-08-30
tmin12Znearest90d22 1 QC4.60 [3.80, 5.80]2.10+4.60 [3.80, 5.80]5.23 [4.44, 6.25]9% [0%, 15%]18%27%+0.04+0.432026-08-09 → 2026-08-30
tmin12Znearest365d22 1 QC4.60 [3.74, 5.74]2.10+4.60 [3.74, 5.74]5.23 [4.42, 6.16]9% [0%, 15%]18%27%+0.04+0.432026-08-09 → 2026-08-30
tmin12Znearestall22 1 QC4.60 [3.66, 5.69]2.10+4.60 [3.66, 5.69]5.23 [4.20, 6.18]9% [0%, 15%]18%27%+0.04+0.432026-08-09 → 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 8, 00Z bilinear tmax+10+50-5-102026-08-09: -2.75 °F2026-08-10: -0.99 °F2026-08-11: +0.52 °F2026-08-12: -7.81 °F2026-08-13: +1.21 °F2026-08-14: -5.07 °F2026-08-15: -2.6 °F2026-08-16: -0.29 °F2026-08-17: -2.29 °F2026-08-18: -0 °F2026-08-19: +1.41 °F2026-08-20: +4.52 °F2026-08-21: -2.16 °F2026-08-22: +3.53 °F2026-08-23: -1.42 °F2026-08-24: -3.34 °F2026-08-25: -2.03 °F2026-08-26: -1.52 °F2026-08-27: +1.06 °F2026-08-28: +0.25 °F2026-08-29: -2.55 °F2026-08-30: -0.86 °F2026-08-092026-08-30°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 (22 days, newest first) · download CSV
Climatological dayError °F
2026-08-30-0.86
2026-08-29-2.55
2026-08-28+0.25
2026-08-27+1.06
2026-08-26-1.52
2026-08-25-2.03
2026-08-24-3.34
2026-08-23-1.42
2026-08-22+3.53
2026-08-21-2.16
2026-08-20+4.52
2026-08-19+1.41
2026-08-18-0.00
2026-08-17-2.29
2026-08-16-0.29
2026-08-15-2.60
2026-08-14-5.07
2026-08-13+1.21
2026-08-12-7.81
2026-08-11+0.52
2026-08-10-0.99
2026-08-09-2.75

Error distribution

Distribution of the signed daily error in °F for ECMWF AIFS Single at KTTN, lead day 8-10 to -9 °F: 0 days-9 to -8 °F: 0 days-8 to -7 °F: 1 day-7 to -6 °F: 0 days-6 to -5 °F: 1 day-5 to -4 °F: 0 days-4 to -3 °F: 1 day-3 to -2 °F: 6 days-2 to -1 °F: 2 days-1 to 0 °F: 4 days0 to 1 °F: 2 days1 to 2 °F: 3 days2 to 3 °F: 0 days3 to 4 °F: 1 day4 to 5 °F: 1 day5 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| 1.77 · P90 |e| 4.42 °F-100+10 °Fn = 22 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
-8.00-7.001
-7.00-6.000
-6.00-5.001
-5.00-4.000
-4.00-3.001
-3.00-2.006
-2.00-1.002
-1.00+0.004
+0.00+1.002
+1.00+2.003
+2.00+3.000
+3.00+4.001
+4.00+5.001
+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
2026-08222.19 -1.05

Availability

ModelScored period DaysCoverage
ECMWF AIFS Single2026-08-09 → 2026-08-30 22
ECMWF AIFS Single2026-08-09 → 2026-08-30 22
ECMWF AIFS Single2026-08-09 → 2026-08-30 22
ECMWF AIFS Single2026-08-09 → 2026-08-30 22

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 22 -2.60 [-3.51, -1.56] yes
GraphCast (IFS init) 22 -1.25 [-2.41, -0.24] yes
ECMWF IFS HRES 17 -0.76 [-1.74, 0.16] no
Persistence (baseline) 22 -1.58 [-2.84, 0.19] no

Cite this page

ShortCastCheck, KTTN aifs_single lead 8, methodology v0.2, accessed 2026-08-31, https://castcheck.zifanzhang.com/station/KTTN/model/aifs_single/lead/8/

LongCastCheck (2026). Station-level verification of raw weather-model 2 m temperature forecasts: KTTN (Trenton Mercer), model aifs_single, lead day 8. 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/8/

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