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

Seattle-Tacoma · ECMWF IFS HRES · lead day 4

KSEA · 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 QC2.79 [1.57, 3.79]2.27-1.68 [-2.92, -0.05]3.57 [1.98, 4.56]25% [11%, 42%]50%60%+0.50+0.592026-08-05 → 2026-08-30
tmax00Zbilinear90d20 1 QC2.79 [1.29, 3.82]2.27-1.68 [-2.97, 0.05]3.57 [1.38, 4.59]25% [8%, 50%]50%60%+0.50+0.592026-08-05 → 2026-08-30
tmax00Zbilinear365d20 1 QC2.79 [1.22, 3.93]2.27-1.68 [-3.02, 0.13]3.57 [1.38, 4.62]25% [0%, 50%]50%60%+0.50+0.592026-08-05 → 2026-08-30
tmax00Zbilinearall20 1 QC2.79 [1.09, 3.70]2.27-1.68 [-3.06, 0.12]3.57 [1.16, 4.49]25% [0%, 50%]50%60%+0.50+0.592026-08-05 → 2026-08-30
tmax00Znearest30d20 1 QC3.06 [1.91, 4.05]2.33-2.01 [-3.19, -0.45]3.79 [2.31, 4.81]20% [9%, 33%]45%55%+0.45+0.572026-08-05 → 2026-08-30
tmax00Znearest90d20 1 QC3.06 [1.65, 4.09]2.33-2.01 [-3.26, -0.41]3.79 [1.99, 4.84]20% [7%, 33%]45%55%+0.45+0.572026-08-05 → 2026-08-30
tmax00Znearest365d20 1 QC3.06 [1.57, 4.14]2.33-2.01 [-3.28, -0.29]3.79 [1.94, 4.87]20% [0%, 33%]45%55%+0.45+0.572026-08-05 → 2026-08-30
tmax00Znearestall20 1 QC3.06 [1.50, 3.97]2.33-2.01 [-3.30, -0.27]3.79 [1.60, 4.77]20% [0%, 33%]45%55%+0.45+0.572026-08-05 → 2026-08-30
tmax12Zbilinear30d21 1 QC2.75 [1.39, 3.60]2.32-1.23 [-2.86, 0.57]3.33 [1.75, 4.09]24% [8%, 50%]38%67%+0.50+0.572026-08-05 → 2026-08-30
tmax12Zbilinear90d21 1 QC2.75 [1.04, 3.60]2.32-1.23 [-2.93, 0.59]3.33 [1.37, 4.12]24% [6%, 60%]38%67%+0.50+0.572026-08-05 → 2026-08-30
tmax12Zbilinear365d21 1 QC2.75 [1.16, 3.67]2.32-1.23 [-2.98, 0.69]3.33 [1.46, 4.17]24% [6%, 60%]38%67%+0.50+0.572026-08-05 → 2026-08-30
tmax12Zbilinearall21 1 QC2.75 [1.01, 3.58]2.32-1.23 [-3.03, 0.74]3.33 [1.30, 4.08]24% [4%, 62%]38%67%+0.50+0.572026-08-05 → 2026-08-30
tmax12Znearest30d21 1 QC3.00 [1.67, 3.85]2.40-1.63 [-3.26, 0.17]3.53 [2.11, 4.28]24% [8%, 50%]33%52%+0.45+0.552026-08-05 → 2026-08-30
tmax12Znearest90d21 1 QC3.00 [1.41, 3.91]2.40-1.63 [-3.37, 0.18]3.53 [1.74, 4.31]24% [6%, 60%]33%52%+0.45+0.552026-08-05 → 2026-08-30
tmax12Znearest365d21 1 QC3.00 [1.47, 3.89]2.40-1.63 [-3.42, 0.32]3.53 [1.85, 4.31]24% [6%, 60%]33%52%+0.45+0.552026-08-05 → 2026-08-30
tmax12Znearestall21 1 QC3.00 [1.36, 3.87]2.40-1.63 [-3.48, 0.33]3.53 [1.77, 4.26]24% [4%, 62%]33%52%+0.45+0.552026-08-05 → 2026-08-30
tmin00Zbilinear30d20 1 QC2.04 [1.46, 2.86]1.32+1.94 [1.28, 2.78]2.47 [1.82, 3.13]30% [11%, 43%]50%70%-0.13+0.282026-08-05 → 2026-08-30
tmin00Zbilinear90d20 1 QC2.04 [1.37, 3.05]1.32+1.94 [1.17, 3.05]2.47 [1.70, 3.25]30% [0%, 46%]50%70%-0.13+0.282026-08-05 → 2026-08-30
tmin00Zbilinear365d20 1 QC2.04 [1.38, 3.01]1.32+1.94 [1.12, 3.01]2.47 [1.73, 3.25]30% [0%, 50%]50%70%-0.13+0.282026-08-05 → 2026-08-30
tmin00Zbilinearall20 1 QC2.04 [1.33, 3.01]1.32+1.94 [1.12, 3.01]2.47 [1.68, 3.28]30% [0%, 50%]50%70%-0.13+0.282026-08-05 → 2026-08-30
tmin00Znearest30d20 1 QC2.48 [1.81, 3.43]1.31+2.42 [1.71, 3.42]2.89 [2.11, 3.69]15% [0%, 33%]45%65%-0.38+0.282026-08-05 → 2026-08-30
tmin00Znearest90d20 1 QC2.48 [1.71, 3.75]1.31+2.42 [1.57, 3.75]2.89 [1.98, 3.87]15% [0%, 38%]45%65%-0.38+0.282026-08-05 → 2026-08-30
tmin00Znearest365d20 1 QC2.48 [1.70, 3.71]1.31+2.42 [1.53, 3.71]2.89 [1.99, 3.88]15% [0%, 43%]45%65%-0.38+0.282026-08-05 → 2026-08-30
tmin00Znearestall20 1 QC2.48 [1.64, 3.71]1.31+2.42 [1.53, 3.71]2.89 [1.94, 3.90]15% [0%, 42%]45%65%-0.38+0.282026-08-05 → 2026-08-30
tmin12Zbilinear30d21 1 QC1.85 [1.44, 2.41]1.35+1.76 [1.32, 2.35]2.35 [1.85, 2.84]38% [21%, 50%]62%71%-0.02+0.252026-08-05 → 2026-08-30
tmin12Zbilinear90d21 1 QC1.85 [1.35, 2.64]1.35+1.76 [1.28, 2.57]2.35 [1.77, 3.00]38% [15%, 52%]62%71%-0.02+0.252026-08-05 → 2026-08-30
tmin12Zbilinear365d21 1 QC1.85 [1.33, 2.66]1.35+1.76 [1.25, 2.62]2.35 [1.74, 3.02]38% [17%, 53%]62%71%-0.02+0.252026-08-05 → 2026-08-30
tmin12Zbilinearall21 1 QC1.85 [1.35, 2.62]1.35+1.76 [1.21, 2.60]2.35 [1.77, 3.05]38% [15%, 56%]62%71%-0.02+0.252026-08-05 → 2026-08-30
tmin12Znearest30d21 1 QC2.24 [1.68, 3.00]1.38+2.21 [1.62, 2.99]2.73 [2.08, 3.44]33% [11%, 50%]57%67%-0.24+0.242026-08-05 → 2026-08-30
tmin12Znearest90d21 1 QC2.24 [1.61, 3.27]1.38+2.21 [1.57, 3.27]2.73 [1.97, 3.65]33% [0%, 50%]57%67%-0.24+0.242026-08-05 → 2026-08-30
tmin12Znearest365d21 1 QC2.24 [1.56, 3.33]1.38+2.21 [1.54, 3.33]2.73 [1.95, 3.68]33% [0%, 50%]57%67%-0.24+0.242026-08-05 → 2026-08-30
tmin12Znearestall21 1 QC2.24 [1.54, 3.31]1.38+2.21 [1.47, 3.31]2.73 [1.95, 3.68]33% [0%, 55%]57%67%-0.24+0.242026-08-05 → 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 KSEA, lead day 4, 00Z bilinear tmax+10+50-5-102026-08-05: -1.38 °F2026-08-11: +0.51 °F2026-08-12: -3.63 °F2026-08-13: -1.09 °F2026-08-14: +4.69 °F2026-08-16: +5.83 °F2026-08-17: -1.68 °F2026-08-18: -3.35 °F2026-08-19: -8.01 °F2026-08-20: -5.81 °F2026-08-21: -0.01 °F2026-08-22: -5.42 °F2026-08-23: -0.28 °F2026-08-24: -2.75 °F2026-08-25: -2.54 °F2026-08-26: -4.65 °F2026-08-27: -1.45 °F2026-08-28: -1.51 °F2026-08-29: -0.63 °F2026-08-30: -0.54 °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
2026-08-30-0.54
2026-08-29-0.63
2026-08-28-1.51
2026-08-27-1.45
2026-08-26-4.65
2026-08-25-2.54
2026-08-24-2.75
2026-08-23-0.28
2026-08-22-5.42
2026-08-21-0.01
2026-08-20-5.81
2026-08-19-8.01
2026-08-18-3.35
2026-08-17-1.68
2026-08-16+5.83
2026-08-15—
2026-08-14+4.69
2026-08-13-1.09
2026-08-12-3.63
2026-08-11+0.51
2026-08-10—
2026-08-09—
2026-08-08—
2026-08-07—
2026-08-06—
2026-08-05-1.38

Error distribution

Distribution of the signed daily error in °F for ECMWF IFS HRES at KSEA, lead day 4-10 to -9 °F: 0 days-9 to -8 °F: 1 day-8 to -7 °F: 0 days-7 to -6 °F: 0 days-6 to -5 °F: 2 days-5 to -4 °F: 1 day-4 to -3 °F: 2 days-3 to -2 °F: 2 days-2 to -1 °F: 5 days-1 to 0 °F: 4 days0 to 1 °F: 1 day1 to 2 °F: 0 days2 to 3 °F: 0 days3 to 4 °F: 0 days4 to 5 °F: 1 day5 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| 2.11 · P90 |e| 5.81 °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
-9.00-8.001
-8.00-7.000
-7.00-6.000
-6.00-5.002
-5.00-4.001
-4.00-3.002
-3.00-2.002
-2.00-1.005
-1.00+0.004
+0.00+1.001
+1.00+2.000
+2.00+3.000
+3.00+4.000
+4.00+5.001
+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
2026-08202.79 -1.68

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 -2.54 [-3.40, -1.76] yes
NCEP GFS 20 -1.08 [-2.92, 0.56] no
GraphCast (IFS init) 19 -2.80 [-3.69, -2.10] yes
Persistence (baseline) 20 -2.76 [-9.78, -0.88] yes

Cite this page

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

LongCastCheck (2026). Station-level verification of raw weather-model 2 m temperature forecasts: KSEA (Seattle-Tacoma), 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/KSEA/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