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

Washington Reagan · ECMWF AIFS Single · lead day 8

KDCA · 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 QC4.53 [3.60, 5.84]3.08-3.71 [-5.51, -2.48]5.23 [4.43, 6.11]9% [0%, 15%]23%36%-0.08+0.252026-08-09 → 2026-08-30
tmax00Zbilinear90d22 1 QC4.53 [3.41, 6.09]3.08-3.71 [-6.06, -2.36]5.23 [4.29, 6.23]9% [0%, 15%]23%36%-0.08+0.252026-08-09 → 2026-08-30
tmax00Zbilinear365d22 1 QC4.53 [3.46, 6.20]3.08-3.71 [-6.19, -2.36]5.23 [4.28, 6.32]9% [0%, 15%]23%36%-0.08+0.252026-08-09 → 2026-08-30
tmax00Zbilinearall22 1 QC4.53 [3.57, 6.24]3.08-3.71 [-6.24, -2.39]5.23 [4.36, 6.36]9% [0%, 15%]23%36%-0.08+0.252026-08-09 → 2026-08-30
tmax00Znearest30d22 1 QC4.35 [3.42, 5.66]3.13-3.41 [-5.31, -2.15]5.08 [4.27, 5.97]18% [0%, 35%]23%36%-0.04+0.242026-08-09 → 2026-08-30
tmax00Znearest90d22 1 QC4.35 [3.20, 5.96]3.13-3.41 [-5.89, -2.01]5.08 [4.13, 6.10]18% [0%, 38%]23%36%-0.04+0.242026-08-09 → 2026-08-30
tmax00Znearest365d22 1 QC4.35 [3.24, 6.01]3.13-3.41 [-6.00, -2.01]5.08 [4.17, 6.17]18% [0%, 39%]23%36%-0.04+0.242026-08-09 → 2026-08-30
tmax00Znearestall22 1 QC4.35 [3.34, 6.07]3.13-3.41 [-6.07, -2.02]5.08 [4.23, 6.21]18% [0%, 36%]23%36%-0.04+0.242026-08-09 → 2026-08-30
tmax12Zbilinear30d22 1 QC4.03 [2.30, 6.45]3.23-3.95 [-6.44, -2.13]5.32 [3.52, 7.22]36% [7%, 61%]45%50%+0.04+0.212026-08-09 → 2026-08-30
tmax12Zbilinear90d22 1 QC4.03 [2.23, 7.58]3.23-3.95 [-7.58, -2.09]5.32 [3.32, 7.96]36% [0%, 62%]45%50%+0.04+0.212026-08-09 → 2026-08-30
tmax12Zbilinear365d22 1 QC4.03 [2.15, 7.74]3.23-3.95 [-7.74, -2.05]5.32 [3.18, 8.10]36% [0%, 64%]45%50%+0.04+0.212026-08-09 → 2026-08-30
tmax12Zbilinearall22 1 QC4.03 [2.21, 8.06]3.23-3.95 [-8.06, -2.08]5.32 [3.22, 8.37]36% [0%, 62%]45%50%+0.04+0.212026-08-09 → 2026-08-30
tmax12Znearest30d22 1 QC3.87 [2.20, 6.21]3.25-3.70 [-6.16, -1.90]5.16 [3.43, 6.97]32% [7%, 52%]45%50%+0.08+0.212026-08-09 → 2026-08-30
tmax12Znearest90d22 1 QC3.87 [2.12, 7.31]3.25-3.70 [-7.31, -1.85]5.16 [3.20, 7.68]32% [0%, 50%]45%50%+0.08+0.212026-08-09 → 2026-08-30
tmax12Znearest365d22 1 QC3.87 [2.02, 7.47]3.25-3.70 [-7.47, -1.80]5.16 [3.07, 7.83]32% [0%, 52%]45%50%+0.08+0.212026-08-09 → 2026-08-30
tmax12Znearestall22 1 QC3.87 [2.09, 7.78]3.25-3.70 [-7.78, -1.85]5.16 [3.11, 8.08]32% [0%, 50%]45%50%+0.08+0.212026-08-09 → 2026-08-30
tmin00Zbilinear30d22 1 QC2.73 [2.13, 3.33]2.76+0.30 [-2.00, 2.12]3.38 [2.70, 3.95]27% [10%, 42%]45%59%+0.43+0.422026-08-09 → 2026-08-30
tmin00Zbilinear90d22 1 QC2.73 [2.14, 3.40]2.76+0.30 [-2.86, 2.37]3.38 [2.71, 3.95]27% [9%, 43%]45%59%+0.43+0.422026-08-09 → 2026-08-30
tmin00Zbilinear365d22 1 QC2.73 [1.99, 3.43]2.76+0.30 [-2.89, 2.47]3.38 [2.53, 3.97]27% [0%, 44%]45%59%+0.43+0.422026-08-09 → 2026-08-30
tmin00Zbilinearall22 1 QC2.73 [1.98, 3.42]2.76+0.30 [-3.33, 2.29]3.38 [2.46, 3.97]27% [0%, 43%]45%59%+0.43+0.422026-08-09 → 2026-08-30
tmin00Znearest30d22 1 QC2.71 [2.12, 3.30]2.75+0.57 [-1.72, 2.39]3.41 [2.65, 4.05]27% [14%, 38%]45%64%+0.44+0.422026-08-09 → 2026-08-30
tmin00Znearest90d22 1 QC2.71 [2.15, 3.28]2.75+0.57 [-2.57, 2.65]3.41 [2.66, 4.07]27% [12%, 39%]45%64%+0.44+0.422026-08-09 → 2026-08-30
tmin00Znearest365d22 1 QC2.71 [1.99, 3.37]2.75+0.57 [-2.62, 2.74]3.41 [2.46, 4.09]27% [9%, 40%]45%64%+0.44+0.422026-08-09 → 2026-08-30
tmin00Znearestall22 1 QC2.71 [1.95, 3.26]2.75+0.57 [-3.02, 2.58]3.41 [2.40, 4.09]27% [10%, 40%]45%64%+0.44+0.422026-08-09 → 2026-08-30
tmin12Zbilinear30d22 1 QC2.61 [2.13, 3.22]2.48+0.54 [-1.59, 2.39]3.16 [2.64, 3.78]27% [15%, 38%]50%59%+0.46+0.482026-08-09 → 2026-08-30
tmin12Zbilinear90d22 1 QC2.61 [2.15, 3.33]2.48+0.54 [-2.44, 2.85]3.16 [2.64, 3.89]27% [14%, 36%]50%59%+0.46+0.482026-08-09 → 2026-08-30
tmin12Zbilinear365d22 1 QC2.61 [2.08, 3.33]2.48+0.54 [-2.48, 2.88]3.16 [2.49, 3.83]27% [14%, 38%]50%59%+0.46+0.482026-08-09 → 2026-08-30
tmin12Zbilinearall22 1 QC2.61 [2.05, 3.49]2.48+0.54 [-3.14, 2.75]3.16 [2.49, 4.10]27% [14%, 38%]50%59%+0.46+0.482026-08-09 → 2026-08-30
tmin12Znearest30d22 1 QC2.71 [2.22, 3.29]2.47+0.84 [-1.31, 2.69]3.24 [2.69, 3.84]18% [11%, 27%]41%59%+0.44+0.482026-08-09 → 2026-08-30
tmin12Znearest90d22 1 QC2.71 [2.21, 3.36]2.47+0.84 [-2.13, 3.13]3.24 [2.67, 3.95]18% [10%, 27%]41%59%+0.44+0.482026-08-09 → 2026-08-30
tmin12Znearest365d22 1 QC2.71 [2.14, 3.34]2.47+0.84 [-2.16, 3.20]3.24 [2.56, 3.91]18% [10%, 29%]41%59%+0.44+0.482026-08-09 → 2026-08-30
tmin12Znearestall22 1 QC2.71 [2.12, 3.40]2.47+0.84 [-2.83, 3.06]3.24 [2.51, 4.04]18% [10%, 29%]41%59%+0.44+0.482026-08-09 → 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 KDCA, lead day 8, 00Z bilinear tmax+10+50-5-102026-08-09: -5.1 °F2026-08-10: -1.51 °F2026-08-11: -2.51 °F2026-08-12: -7.43 °F2026-08-13: -0.35 °F2026-08-14: +4.7 °F2026-08-15: -4.64 °F2026-08-16: -4.4 °F2026-08-17: -9.86 °F2026-08-18: -2.39 °F2026-08-19: -1.13 °F2026-08-20: -0.12 °F2026-08-21: -1.32 °F2026-08-22: +4.26 °F2026-08-23: -7.49 °F2026-08-24: -6.72 °F2026-08-25: -5.92 °F2026-08-26: -2.86 °F2026-08-27: -6.78 °F2026-08-28: -6.74 °F2026-08-29: -6.89 °F2026-08-30: -6.51 °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
2026-08-30-6.51
2026-08-29-6.89
2026-08-28-6.74
2026-08-27-6.78
2026-08-26-2.86
2026-08-25-5.92
2026-08-24-6.72
2026-08-23-7.49
2026-08-22+4.26
2026-08-21-1.32
2026-08-20-0.12
2026-08-19-1.13
2026-08-18-2.39
2026-08-17-9.86
2026-08-16-4.40
2026-08-15-4.64
2026-08-14+4.70
2026-08-13-0.35
2026-08-12-7.43
2026-08-11-2.51
2026-08-10-1.51
2026-08-09-5.10

Error distribution

Distribution of the signed daily error in °F for ECMWF AIFS Single at KDCA, lead day 8-10 to -9 °F: 1 day-9 to -8 °F: 0 days-8 to -7 °F: 2 days-7 to -6 °F: 5 days-6 to -5 °F: 2 days-5 to -4 °F: 2 days-4 to -3 °F: 0 days-3 to -2 °F: 3 days-2 to -1 °F: 3 days-1 to 0 °F: 2 days0 to 1 °F: 0 days1 to 2 °F: 0 days2 to 3 °F: 0 days3 to 4 °F: 0 days4 to 5 °F: 2 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| 4.67 · P90 |e| 7.37 °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
-10.00-9.001
-9.00-8.000
-8.00-7.002
-7.00-6.005
-6.00-5.002
-5.00-4.002
-4.00-3.000
-3.00-2.003
-2.00-1.003
-1.00+0.002
+0.00+1.000
+1.00+2.000
+2.00+3.000
+3.00+4.000
+4.00+5.002
+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
2026-08224.53 -3.71

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 -1.08 [-2.25, 0.47] no
GraphCast (IFS init) 22 -1.89 [-3.56, -0.55] yes
ECMWF IFS HRES 17 +1.72 [0.45, 3.32] yes
Persistence (baseline) 22 +0.35 [-1.23, 1.87] no

Cite this page

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

LongCastCheck (2026). Station-level verification of raw weather-model 2 m temperature forecasts: KDCA (Washington Reagan), 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/KDCA/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