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

Seattle-Tacoma · ECMWF AIFS Single · lead day 0

KSEA · aifs_single · lead 0

Target day = initialization date + 0 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
tmax00Zbilinear30d30 1 QC5.66 [4.57, 6.84]1.63-5.66 [-6.84, -4.57]6.01 [4.91, 7.13]0% [0%, 0%]7%13%——2026-08-01 → 2026-08-30
tmax00Zbilinear90d30 1 QC5.66 [4.44, 6.86]1.63-5.66 [-6.86, -4.44]6.01 [4.77, 7.10]0% [0%, 0%]7%13%——2026-08-01 → 2026-08-30
tmax00Zbilinear365d30 1 QC5.66 [4.44, 6.97]1.63-5.66 [-6.97, -4.44]6.01 [4.77, 7.20]0% [0%, 0%]7%13%——2026-08-01 → 2026-08-30
tmax00Zbilinearall30 1 QC5.66 [4.25, 6.90]1.63-5.66 [-6.90, -4.25]6.01 [4.65, 7.12]0% [0%, 0%]7%13%——2026-08-01 → 2026-08-30
tmax00Znearest30d30 1 QC5.31 [4.20, 6.53]1.66-5.31 [-6.53, -4.20]5.70 [4.57, 6.86]3% [0%, 10%]7%17%——2026-08-01 → 2026-08-30
tmax00Znearest90d30 1 QC5.31 [4.07, 6.58]1.66-5.31 [-6.58, -4.07]5.70 [4.40, 6.85]3% [0%, 11%]7%17%——2026-08-01 → 2026-08-30
tmax00Znearest365d30 1 QC5.31 [4.06, 6.67]1.66-5.31 [-6.67, -4.06]5.70 [4.42, 6.93]3% [0%, 11%]7%17%——2026-08-01 → 2026-08-30
tmax00Znearestall30 1 QC5.31 [3.88, 6.60]1.66-5.31 [-6.60, -3.88]5.70 [4.29, 6.88]3% [0%, 12%]7%17%——2026-08-01 → 2026-08-30
tmin00Zbilinear30d30 1 QC2.37 [1.58, 3.24]1.37-2.24 [-3.21, -1.31]2.83 [1.94, 3.65]27% [13%, 43%]43%70%——2026-08-01 → 2026-08-30
tmin00Zbilinear90d30 1 QC2.37 [1.55, 3.30]1.37-2.24 [-3.30, -1.30]2.83 [1.91, 3.70]27% [12%, 44%]43%70%——2026-08-01 → 2026-08-30
tmin00Zbilinear365d30 1 QC2.37 [1.50, 3.29]1.37-2.24 [-3.29, -1.19]2.83 [1.84, 3.70]27% [11%, 44%]43%70%——2026-08-01 → 2026-08-30
tmin00Zbilinearall30 1 QC2.37 [1.57, 3.30]1.37-2.24 [-3.30, -1.28]2.83 [1.90, 3.70]27% [11%, 43%]43%70%——2026-08-01 → 2026-08-30
tmin00Znearest30d30 1 QC2.31 [1.52, 3.21]1.44-2.15 [-3.18, -1.18]2.84 [1.86, 3.69]27% [13%, 43%]40%70%——2026-08-01 → 2026-08-30
tmin00Znearest90d30 1 QC2.31 [1.48, 3.27]1.44-2.15 [-3.25, -1.20]2.84 [1.81, 3.77]27% [12%, 44%]40%70%——2026-08-01 → 2026-08-30
tmin00Znearest365d30 1 QC2.31 [1.44, 3.28]1.44-2.15 [-3.24, -1.11]2.84 [1.78, 3.76]27% [11%, 44%]40%70%——2026-08-01 → 2026-08-30
tmin00Znearestall30 1 QC2.31 [1.48, 3.29]1.44-2.15 [-3.29, -1.17]2.84 [1.83, 3.76]27% [11%, 43%]40%70%——2026-08-01 → 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 KSEA, lead day 0, 00Z bilinear tmax+10+50-5-102026-08-01: -3.18 °F2026-08-02: -4.09 °F2026-08-03: -2.74 °F2026-08-04: -1.48 °F2026-08-05: -5.84 °F2026-08-06: -7.38 °F2026-08-07: -7.5 °F2026-08-08: -5.8 °F2026-08-09: -4.48 °F2026-08-10: -1.47 °F2026-08-11: -5.18 °F2026-08-12: -6.84 °F2026-08-13: -4.36 °F2026-08-14: -5.33 °F2026-08-15: -6.59 °F2026-08-16: -7.5 °F2026-08-17: -7.39 °F2026-08-18: -6.9 °F2026-08-19: -9.05 °F2026-08-20: -7.98 °F2026-08-21: -8.17 °F2026-08-22: -9.71 °F2026-08-23: -5.12 °F2026-08-24: -5.46 °F2026-08-25: -6.63 °F2026-08-26: -4.86 °F2026-08-27: -4.69 °F2026-08-28: -5.01 °F2026-08-29: -6.14 °F2026-08-30: -2.98 °F2026-08-012026-08-30°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 (30 days, newest first) · download CSV
Climatological dayError °F
2026-08-30-2.98
2026-08-29-6.14
2026-08-28-5.01
2026-08-27-4.69
2026-08-26-4.86
2026-08-25-6.63
2026-08-24-5.46
2026-08-23-5.12
2026-08-22-9.71
2026-08-21-8.17
2026-08-20-7.98
2026-08-19-9.05
2026-08-18-6.90
2026-08-17-7.39
2026-08-16-7.50
2026-08-15-6.59
2026-08-14-5.33
2026-08-13-4.36
2026-08-12-6.84
2026-08-11-5.18
2026-08-10-1.47
2026-08-09-4.48
2026-08-08-5.80
2026-08-07-7.50
2026-08-06-7.38
2026-08-05-5.84
2026-08-04-1.48
2026-08-03-2.74
2026-08-02-4.09
2026-08-01-3.18

Error distribution

Distribution of the signed daily error in °F for ECMWF AIFS Single at KSEA, lead day 0-10 to -9 °F: 2 days-9 to -8 °F: 1 day-8 to -7 °F: 5 days-7 to -6 °F: 5 days-6 to -5 °F: 7 days-5 to -4 °F: 5 days-4 to -3 °F: 1 day-3 to -2 °F: 2 days-2 to -1 °F: 2 days-1 to 0 °F: 0 days0 to 1 °F: 0 days1 to 2 °F: 0 days2 to 3 °F: 0 days3 to 4 °F: 0 days4 to 5 °F: 0 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| 5.63 · P90 |e| 7.99 °F-100+10 °Fn = 30 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
-10.00-9.002
-9.00-8.001
-8.00-7.005
-7.00-6.005
-6.00-5.007
-5.00-4.005
-4.00-3.001
-3.00-2.002
-2.00-1.002
-1.00+0.000
+0.00+1.000
+1.00+2.000
+2.00+3.000
+3.00+4.000
+4.00+5.000
+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
2026-08305.66 -5.66

Availability

ModelScored period DaysCoverage
ECMWF AIFS Single2026-08-01 → 2026-08-30 30
ECMWF AIFS Single2026-08-01 → 2026-08-30 30

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
Aurora (GFS init) 2 -0.54 [-0.57, -0.51] yes
Aurora (IFS init) 3 +1.38 [1.03, 2.09] yes
FourCastNet v2 (GFS init) 2 +0.84 [-0.25, 1.92] no
FourCastNet v2 (IFS init) 3 +2.55 [2.16, 3.33] yes
NCEP GFS 30 +1.81 [0.15, 3.56] yes
GraphCast (GFS init) 2 -1.57 [-1.92, -1.21] yes
GraphCast (IFS init) 28 +1.39 [0.32, 2.13] yes
ECMWF IFS HRES 25 +4.15 [3.05, 5.22] yes
Pangu-Weather (GFS init) 2 +0.78 [-0.62, 2.18] no
Pangu-Weather (IFS init) 3 +2.93 [2.01, 4.28] yes

Cite this page

ShortCastCheck, KSEA aifs_single lead 0, methodology v0.2, accessed 2026-08-31, https://castcheck.zifanzhang.com/station/KSEA/model/aifs_single/lead/0/

LongCastCheck (2026). Station-level verification of raw weather-model 2 m temperature forecasts: KSEA (Seattle-Tacoma), model aifs_single, lead day 0. Methodology version 0.2, schema version 0.1, data through 2026-08-30. Accessed 2026-08-31. https://castcheck.zifanzhang.com/station/KSEA/model/aifs_single/lead/0/

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

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