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

Washington Reagan · ECMWF AIFS Single · lead day 9

KDCA · aifs_single · lead 9

Target day = initialization date + 9 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
tmax00Zbilinear30d21 1 QC4.55 [2.96, 6.09]3.54-3.42 [-5.67, -1.71]5.58 [3.87, 7.05]5% [0%, 19%]24%48%-0.10+0.112026-08-10 → 2026-08-30
tmax00Zbilinear90d21 1 QC4.55 [2.33, 6.22]3.54-3.42 [-6.19, -1.45]5.58 [2.83, 7.20]5% [0%, 25%]24%48%-0.10+0.112026-08-10 → 2026-08-30
tmax00Zbilinear365d21 1 QC4.55 [2.31, 6.42]3.54-3.42 [-6.29, -1.42]5.58 [2.80, 7.22]5% [0%, 20%]24%48%-0.10+0.112026-08-10 → 2026-08-30
tmax00Zbilinearall21 1 QC4.55 [2.33, 6.59]3.54-3.42 [-6.59, -1.46]5.58 [2.83, 7.45]5% [0%, 22%]24%48%-0.10+0.112026-08-10 → 2026-08-30
tmax00Znearest30d21 1 QC4.39 [2.81, 5.92]3.54-3.15 [-5.38, -1.48]5.41 [3.70, 6.87]10% [0%, 33%]29%43%-0.06+0.112026-08-10 → 2026-08-30
tmax00Znearest90d21 1 QC4.39 [2.11, 6.05]3.54-3.15 [-6.02, -1.18]5.41 [2.54, 7.07]10% [0%, 43%]29%43%-0.06+0.112026-08-10 → 2026-08-30
tmax00Znearest365d21 1 QC4.39 [2.11, 6.23]3.54-3.15 [-6.09, -1.20]5.41 [2.54, 7.08]10% [0%, 40%]29%43%-0.06+0.112026-08-10 → 2026-08-30
tmax00Znearestall21 1 QC4.39 [2.11, 6.37]3.54-3.15 [-6.37, -1.20]5.41 [2.54, 7.25]10% [0%, 39%]29%43%-0.06+0.112026-08-10 → 2026-08-30
tmax12Zbilinear30d21 1 QC4.97 [3.19, 7.68]4.11-3.85 [-7.45, -1.50]6.36 [4.43, 8.49]24% [5%, 41%]33%38%-0.20-0.042026-08-10 → 2026-08-30
tmax12Zbilinear90d21 1 QC4.97 [2.85, 8.55]4.11-3.85 [-8.55, -1.36]6.36 [4.09, 9.07]24% [0%, 46%]33%38%-0.20-0.042026-08-10 → 2026-08-30
tmax12Zbilinear365d21 1 QC4.97 [2.79, 8.62]4.11-3.85 [-8.62, -1.28]6.36 [3.81, 9.21]24% [0%, 50%]33%38%-0.20-0.042026-08-10 → 2026-08-30
tmax12Zbilinearall21 1 QC4.97 [2.82, 9.13]4.11-3.85 [-9.13, -1.25]6.36 [3.98, 9.61]24% [0%, 47%]33%38%-0.20-0.042026-08-10 → 2026-08-30
tmax12Znearest30d21 1 QC4.88 [3.14, 7.53]4.13-3.58 [-7.26, -1.20]6.24 [4.36, 8.33]19% [0%, 40%]33%38%-0.18-0.042026-08-10 → 2026-08-30
tmax12Znearest90d21 1 QC4.88 [2.83, 8.35]4.13-3.58 [-8.35, -1.05]6.24 [4.02, 8.91]19% [0%, 45%]33%38%-0.18-0.042026-08-10 → 2026-08-30
tmax12Znearest365d21 1 QC4.88 [2.76, 8.42]4.13-3.58 [-8.42, -0.97]6.24 [3.76, 9.02]19% [0%, 50%]33%38%-0.18-0.042026-08-10 → 2026-08-30
tmax12Znearestall21 1 QC4.88 [2.83, 8.93]4.13-3.58 [-8.93, -0.92]6.24 [3.92, 9.44]19% [0%, 46%]33%38%-0.18-0.042026-08-10 → 2026-08-30
tmin00Zbilinear30d21 1 QC4.09 [2.95, 5.33]4.05+0.79 [-2.17, 3.44]4.77 [3.55, 5.92]5% [0%, 14%]24%33%+0.00-0.022026-08-10 → 2026-08-30
tmin00Zbilinear90d21 1 QC4.09 [2.94, 5.50]4.05+0.79 [-2.79, 4.01]4.77 [3.50, 5.99]5% [0%, 16%]24%33%+0.00-0.022026-08-10 → 2026-08-30
tmin00Zbilinear365d21 1 QC4.09 [2.80, 5.53]4.05+0.79 [-3.34, 4.05]4.77 [3.26, 6.02]5% [0%, 17%]24%33%+0.00-0.022026-08-10 → 2026-08-30
tmin00Zbilinearall21 1 QC4.09 [2.84, 5.60]4.05+0.79 [-3.41, 4.30]4.77 [3.36, 6.10]5% [0%, 17%]24%33%+0.00-0.022026-08-10 → 2026-08-30
tmin00Znearest30d21 1 QC4.09 [2.97, 5.41]4.03+1.07 [-1.86, 3.69]4.79 [3.50, 6.01]5% [0%, 14%]24%38%+0.00-0.012026-08-10 → 2026-08-30
tmin00Znearest90d21 1 QC4.09 [2.93, 5.59]4.03+1.07 [-2.47, 4.27]4.79 [3.45, 6.08]5% [0%, 16%]24%38%+0.00-0.012026-08-10 → 2026-08-30
tmin00Znearest365d21 1 QC4.09 [2.77, 5.66]4.03+1.07 [-3.00, 4.31]4.79 [3.23, 6.17]5% [0%, 17%]24%38%+0.00-0.012026-08-10 → 2026-08-30
tmin00Znearestall21 1 QC4.09 [2.86, 5.70]4.03+1.07 [-3.07, 4.56]4.79 [3.28, 6.26]5% [0%, 17%]24%38%+0.00-0.012026-08-10 → 2026-08-30
tmin12Zbilinear30d21 1 QC3.89 [2.94, 5.26]3.90+0.21 [-3.33, 3.15]4.69 [3.36, 6.03]5% [0%, 13%]29%43%+0.05+0.022026-08-10 → 2026-08-30
tmin12Zbilinear90d21 1 QC3.89 [2.92, 5.62]3.90+0.21 [-4.76, 3.74]4.69 [3.30, 6.22]5% [0%, 14%]29%43%+0.05+0.022026-08-10 → 2026-08-30
tmin12Zbilinear365d21 1 QC3.89 [2.87, 5.52]3.90+0.21 [-4.98, 3.69]4.69 [3.23, 6.23]5% [0%, 14%]29%43%+0.05+0.022026-08-10 → 2026-08-30
tmin12Zbilinearall21 1 QC3.89 [2.83, 5.85]3.90+0.21 [-5.51, 3.53]4.69 [3.17, 6.42]5% [0%, 14%]29%43%+0.05+0.022026-08-10 → 2026-08-30
tmin12Znearest30d21 1 QC3.87 [2.92, 5.24]3.90+0.52 [-2.99, 3.46]4.71 [3.36, 5.98]10% [0%, 17%]29%48%+0.05+0.022026-08-10 → 2026-08-30
tmin12Znearest90d21 1 QC3.87 [2.86, 5.53]3.90+0.52 [-4.42, 4.07]4.71 [3.31, 6.10]10% [0%, 15%]29%48%+0.05+0.022026-08-10 → 2026-08-30
tmin12Znearest365d21 1 QC3.87 [2.80, 5.44]3.90+0.52 [-4.67, 4.03]4.71 [3.24, 6.11]10% [0%, 15%]29%48%+0.05+0.022026-08-10 → 2026-08-30
tmin12Znearestall21 1 QC3.87 [2.81, 5.57]3.90+0.52 [-5.19, 3.86]4.71 [3.19, 6.24]10% [0%, 15%]29%48%+0.05+0.022026-08-10 → 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 9, 00Z bilinear tmax+20+100-10-202026-08-10: -0.57 °F2026-08-11: -1.12 °F2026-08-12: -2.56 °F2026-08-13: -3.48 °F2026-08-14: +1.08 °F2026-08-15: -5.16 °F2026-08-16: +2.83 °F2026-08-17: -11.96 °F2026-08-18: -6.44 °F2026-08-19: -2.8 °F2026-08-20: -2.25 °F2026-08-21: +2.81 °F2026-08-22: +5.16 °F2026-08-23: -4.53 °F2026-08-24: -1.82 °F2026-08-25: -8.08 °F2026-08-26: -4.16 °F2026-08-27: -10.17 °F2026-08-28: -7.4 °F2026-08-29: -1.21 °F2026-08-30: -9.96 °F2026-08-102026-08-30°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 (21 days, newest first) · download CSV
Climatological dayError °F
2026-08-30-9.96
2026-08-29-1.21
2026-08-28-7.40
2026-08-27-10.17
2026-08-26-4.16
2026-08-25-8.08
2026-08-24-1.82
2026-08-23-4.53
2026-08-22+5.16
2026-08-21+2.81
2026-08-20-2.25
2026-08-19-2.80
2026-08-18-6.44
2026-08-17-11.96
2026-08-16+2.83
2026-08-15-5.16
2026-08-14+1.08
2026-08-13-3.48
2026-08-12-2.56
2026-08-11-1.12
2026-08-10-0.57

Error distribution

Distribution of the signed daily error in °F for ECMWF AIFS Single at KDCA, lead day 9-20 to -18 °F: 0 days-18 to -16 °F: 0 days-16 to -14 °F: 0 days-14 to -12 °F: 0 days-12 to -10 °F: 2 days-10 to -8 °F: 2 days-8 to -6 °F: 2 days-6 to -4 °F: 3 days-4 to -2 °F: 4 days-2 to 0 °F: 4 days0 to 2 °F: 1 day2 to 4 °F: 2 days4 to 6 °F: 1 day6 to 8 °F: 0 days8 to 10 °F: 0 days10 to 12 °F: 0 days12 to 14 °F: 0 days14 to 16 °F: 0 days16 to 18 °F: 0 days18 to 20 °F: 0 daysdashed: P50 |e| 3.48 · P90 |e| 9.96 °F-200+20 °Fn = 21 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
-20.00-18.000
-18.00-16.000
-16.00-14.000
-14.00-12.000
-12.00-10.002
-10.00-8.002
-8.00-6.002
-6.00-4.003
-4.00-2.004
-2.00+0.004
+0.00+2.001
+2.00+4.002
+4.00+6.001
+6.00+8.000
+8.00+10.000
+10.00+12.000
+12.00+14.000
+14.00+16.000
+16.00+18.000
+18.00+20.000

Month by month

00Z bilinear daily maximum, newest first.

Monthn MAE °FBias °F
2026-08214.55 -3.42

Availability

ModelScored period DaysCoverage
ECMWF AIFS Single2026-08-10 → 2026-08-30 21
ECMWF AIFS Single2026-08-10 → 2026-08-30 21
ECMWF AIFS Single2026-08-10 → 2026-08-30 21
ECMWF AIFS Single2026-08-10 → 2026-08-30 21

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 21 -2.72 [-4.47, -0.76] yes
GraphCast (IFS init) 21 -1.91 [-3.46, -0.76] yes
ECMWF IFS HRES 16 +0.78 [-3.08, 3.34] no
Persistence (baseline) 21 +0.41 [-1.42, 1.86] no

Cite this page

ShortCastCheck, KDCA aifs_single lead 9, methodology v0.2, accessed 2026-08-31, https://castcheck.zifanzhang.com/station/KDCA/model/aifs_single/lead/9/

LongCastCheck (2026). Station-level verification of raw weather-model 2 m temperature forecasts: KDCA (Washington Reagan), model aifs_single, lead day 9. 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/9/

Accessed2026-08-31 (data through 2026-08-30; page built 2026-08-31T03:52:06+00:00)

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