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

Washington Reagan · ECMWF IFS HRES · lead day 4

KDCA · ifs_hres · lead 4

Target day = initialization date + 4 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, ifs-gpid161, 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
tmax00Zbilinear30d20 1 QC3.47 [2.89, 4.10]2.80-1.84 [-2.88, -0.21]3.94 [3.23, 4.62]5% [0%, 14%]25%50%+0.28+0.422026-08-05 → 2026-08-30
tmax00Zbilinear90d20 1 QC3.47 [2.85, 4.18]2.80-1.84 [-3.14, 0.19]3.94 [3.16, 4.68]5% [0%, 13%]25%50%+0.28+0.422026-08-05 → 2026-08-30
tmax00Zbilinear365d20 1 QC3.47 [2.76, 4.23]2.80-1.84 [-3.12, 0.18]3.94 [3.08, 4.74]5% [0%, 14%]25%50%+0.28+0.422026-08-05 → 2026-08-30
tmax00Zbilinearall20 1 QC3.47 [2.76, 4.26]2.80-1.84 [-3.13, 0.14]3.94 [3.09, 4.72]5% [0%, 14%]25%50%+0.28+0.422026-08-05 → 2026-08-30
tmax00Znearest30d20 1 QC3.20 [2.41, 4.10]2.91-1.20 [-2.35, 0.42]3.81 [2.88, 4.68]20% [7%, 30%]30%50%+0.33+0.392026-08-05 → 2026-08-30
tmax00Znearest90d20 1 QC3.20 [2.41, 4.18]2.91-1.20 [-2.67, 0.87]3.81 [2.89, 4.76]20% [0%, 29%]30%50%+0.33+0.392026-08-05 → 2026-08-30
tmax00Znearest365d20 1 QC3.20 [2.30, 4.26]2.91-1.20 [-2.63, 0.88]3.81 [2.69, 4.82]20% [0%, 30%]30%50%+0.33+0.392026-08-05 → 2026-08-30
tmax00Znearestall20 1 QC3.20 [2.29, 4.31]2.91-1.20 [-2.62, 0.75]3.81 [2.71, 4.85]20% [0%, 29%]30%50%+0.33+0.392026-08-05 → 2026-08-30
tmax12Zbilinear30d21 1 QC3.83 [3.18, 4.92]2.96-2.29 [-3.54, -0.41]4.58 [3.59, 5.84]10% [0%, 22%]24%48%+0.16+0.362026-08-05 → 2026-08-30
tmax12Zbilinear90d21 1 QC3.83 [3.06, 5.63]2.96-2.29 [-3.82, 0.05]4.58 [3.44, 6.20]10% [0%, 25%]24%48%+0.16+0.362026-08-05 → 2026-08-30
tmax12Zbilinear365d21 1 QC3.83 [3.00, 5.49]2.96-2.29 [-3.82, -0.11]4.58 [3.39, 6.12]10% [0%, 25%]24%48%+0.16+0.362026-08-05 → 2026-08-30
tmax12Zbilinearall21 1 QC3.83 [3.06, 5.72]2.96-2.29 [-3.99, -0.01]4.58 [3.47, 6.18]10% [0%, 27%]24%48%+0.16+0.362026-08-05 → 2026-08-30
tmax12Znearest30d21 1 QC3.47 [2.68, 4.72]2.91-1.83 [-3.13, -0.05]4.32 [3.20, 5.71]19% [4%, 38%]38%43%+0.24+0.372026-08-05 → 2026-08-30
tmax12Znearest90d21 1 QC3.47 [2.64, 5.26]2.91-1.83 [-3.45, 0.47]4.32 [3.11, 6.10]19% [0%, 41%]38%43%+0.24+0.372026-08-05 → 2026-08-30
tmax12Znearest365d21 1 QC3.47 [2.56, 5.26]2.91-1.83 [-3.44, 0.27]4.32 [3.02, 6.01]19% [0%, 45%]38%43%+0.24+0.372026-08-05 → 2026-08-30
tmax12Znearestall21 1 QC3.47 [2.58, 5.26]2.91-1.83 [-3.71, 0.42]4.32 [3.05, 6.16]19% [0%, 45%]38%43%+0.24+0.372026-08-05 → 2026-08-30
tmin00Zbilinear30d20 1 QC2.44 [1.64, 3.38]2.43+0.48 [-1.05, 1.94]3.33 [2.18, 4.30]45% [27%, 60%]60%70%+0.40+0.392026-08-05 → 2026-08-30
tmin00Zbilinear90d20 1 QC2.44 [1.55, 3.40]2.43+0.48 [-1.32, 2.08]3.33 [1.82, 4.32]45% [21%, 64%]60%70%+0.40+0.392026-08-05 → 2026-08-30
tmin00Zbilinear365d20 1 QC2.44 [1.51, 3.53]2.43+0.48 [-1.28, 2.16]3.33 [1.82, 4.48]45% [20%, 67%]60%70%+0.40+0.392026-08-05 → 2026-08-30
tmin00Zbilinearall20 1 QC2.44 [1.43, 3.57]2.43+0.48 [-1.34, 2.17]3.33 [1.82, 4.55]45% [22%, 67%]60%70%+0.40+0.392026-08-05 → 2026-08-30
tmin00Znearest30d20 1 QC2.45 [1.53, 3.49]2.44+0.57 [-0.94, 2.03]3.37 [2.13, 4.39]40% [17%, 58%]60%70%+0.39+0.392026-08-05 → 2026-08-30
tmin00Znearest90d20 1 QC2.45 [1.36, 3.54]2.44+0.57 [-1.23, 2.20]3.37 [1.72, 4.41]40% [0%, 62%]60%70%+0.39+0.392026-08-05 → 2026-08-30
tmin00Znearest365d20 1 QC2.45 [1.33, 3.66]2.44+0.57 [-1.19, 2.20]3.37 [1.69, 4.56]40% [0%, 65%]60%70%+0.39+0.392026-08-05 → 2026-08-30
tmin00Znearestall20 1 QC2.45 [1.27, 3.72]2.44+0.57 [-1.23, 2.22]3.37 [1.52, 4.66]40% [0%, 67%]60%70%+0.39+0.392026-08-05 → 2026-08-30
tmin12Zbilinear30d21 1 QC2.80 [1.97, 3.72]2.77-0.47 [-1.94, 1.06]3.60 [2.53, 4.54]29% [16%, 44%]48%57%+0.30+0.312026-08-05 → 2026-08-30
tmin12Zbilinear90d21 1 QC2.80 [1.68, 3.80]2.77-0.47 [-2.19, 1.17]3.60 [2.35, 4.65]29% [12%, 50%]48%57%+0.30+0.312026-08-05 → 2026-08-30
tmin12Zbilinear365d21 1 QC2.80 [1.65, 3.91]2.77-0.47 [-2.21, 1.19]3.60 [2.29, 4.70]29% [11%, 50%]48%57%+0.30+0.312026-08-05 → 2026-08-30
tmin12Zbilinearall21 1 QC2.80 [1.65, 3.89]2.77-0.47 [-2.46, 1.42]3.60 [2.24, 4.74]29% [11%, 50%]48%57%+0.30+0.312026-08-05 → 2026-08-30
tmin12Znearest30d21 1 QC2.72 [1.95, 3.52]2.66-0.43 [-1.94, 1.14]3.47 [2.55, 4.25]33% [17%, 50%]57%62%+0.32+0.332026-08-05 → 2026-08-30
tmin12Znearest90d21 1 QC2.72 [1.76, 3.59]2.66-0.43 [-2.14, 1.25]3.47 [2.42, 4.27]33% [12%, 56%]57%62%+0.32+0.332026-08-05 → 2026-08-30
tmin12Znearest365d21 1 QC2.72 [1.70, 3.66]2.66-0.43 [-2.14, 1.27]3.47 [2.34, 4.36]33% [11%, 58%]57%62%+0.32+0.332026-08-05 → 2026-08-30
tmin12Znearestall21 1 QC2.72 [1.70, 3.66]2.66-0.43 [-2.31, 1.47]3.47 [2.28, 4.38]33% [12%, 58%]57%62%+0.32+0.332026-08-05 → 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 IFS HRES at KDCA, lead day 4, 00Z bilinear tmax+10+50-5-102026-08-05: -3.2 °F2026-08-11: +6.04 °F2026-08-12: +2.84 °F2026-08-13: -1.54 °F2026-08-14: -7.65 °F2026-08-16: +4.04 °F2026-08-17: -5.05 °F2026-08-18: -0.11 °F2026-08-19: -4.14 °F2026-08-20: -2.79 °F2026-08-21: -2.43 °F2026-08-22: +1.91 °F2026-08-23: -2.36 °F2026-08-24: -4.66 °F2026-08-25: -6.27 °F2026-08-26: -1.37 °F2026-08-27: -4.47 °F2026-08-28: -4.7 °F2026-08-29: +1.47 °F2026-08-30: -2.31 °F2026-08-052026-08-30°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 (26 days, newest first) · download CSV
Climatological dayError °F
2026-08-30-2.31
2026-08-29+1.47
2026-08-28-4.70
2026-08-27-4.47
2026-08-26-1.37
2026-08-25-6.27
2026-08-24-4.66
2026-08-23-2.36
2026-08-22+1.91
2026-08-21-2.43
2026-08-20-2.79
2026-08-19-4.14
2026-08-18-0.11
2026-08-17-5.05
2026-08-16+4.04
2026-08-15—
2026-08-14-7.65
2026-08-13-1.54
2026-08-12+2.84
2026-08-11+6.04
2026-08-10—
2026-08-09—
2026-08-08—
2026-08-07—
2026-08-06—
2026-08-05-3.20

Error distribution

Distribution of the signed daily error in °F for ECMWF IFS HRES at KDCA, lead day 4-10 to -9 °F: 0 days-9 to -8 °F: 0 days-8 to -7 °F: 1 day-7 to -6 °F: 1 day-6 to -5 °F: 1 day-5 to -4 °F: 4 days-4 to -3 °F: 1 day-3 to -2 °F: 4 days-2 to -1 °F: 2 days-1 to 0 °F: 1 day0 to 1 °F: 0 days1 to 2 °F: 2 days2 to 3 °F: 1 day3 to 4 °F: 0 days4 to 5 °F: 1 day5 to 6 °F: 0 days6 to 7 °F: 1 day7 to 8 °F: 0 days8 to 9 °F: 0 days9 to 10 °F: 0 daysdashed: P50 |e| 3.02 · P90 |e| 6.06 °F-100+10 °Fn = 20 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
-7.00-6.001
-6.00-5.001
-5.00-4.004
-4.00-3.001
-3.00-2.004
-2.00-1.002
-1.00+0.001
+0.00+1.000
+1.00+2.002
+2.00+3.001
+3.00+4.000
+4.00+5.001
+5.00+6.000
+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
2026-08203.47 -1.84

Availability

ModelScored period DaysCoverage
ECMWF IFS HRES2026-08-05 → 2026-08-30 20
ECMWF IFS HRES2026-08-05 → 2026-08-30 20
ECMWF IFS HRES2026-08-05 → 2026-08-30 21
ECMWF IFS HRES2026-08-05 → 2026-08-30 21

Compared with other models

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

Other modelCommon days MAE difference °FDistinguishable
ECMWF AIFS Single 20 +0.37 [-0.77, 2.10] no
NCEP GFS 20 -0.17 [-2.10, 2.16] no
GraphCast (IFS init) 19 -1.06 [-2.43, 1.69] no
Persistence (baseline) 20 -1.33 [-2.91, 1.05] no

Cite this page

ShortCastCheck, KDCA ifs_hres lead 4, methodology v0.2, accessed 2026-08-31, https://castcheck.zifanzhang.com/station/KDCA/model/ifs_hres/lead/4/

LongCastCheck (2026). Station-level verification of raw weather-model 2 m temperature forecasts: KDCA (Washington Reagan), model ifs_hres, lead day 4. Methodology version 0.2, schema version 0.1, data through 2026-08-30. Accessed 2026-08-31. https://castcheck.zifanzhang.com/station/KDCA/model/ifs_hres/lead/4/

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