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

Seattle-Tacoma · ECMWF AIFS Single · lead day 2

KSEA · aifs_single · lead 2

Target day = initialization date + 2 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
tmax00Zbilinear30d28 1 QC5.40 [4.00, 6.81]2.12-5.40 [-6.81, -4.00]5.98 [4.56, 7.29]7% [0%, 17%]7%18%-0.01+0.602026-08-03 → 2026-08-30
tmax00Zbilinear90d28 1 QC5.40 [3.82, 6.99]2.12-5.40 [-6.99, -3.82]5.98 [4.41, 7.43]7% [0%, 18%]7%18%-0.01+0.602026-08-03 → 2026-08-30
tmax00Zbilinear365d28 1 QC5.40 [3.84, 7.11]2.12-5.40 [-7.11, -3.84]5.98 [4.40, 7.51]7% [0%, 19%]7%18%-0.01+0.602026-08-03 → 2026-08-30
tmax00Zbilinearall28 1 QC5.40 [3.71, 7.00]2.12-5.40 [-7.00, -3.71]5.98 [4.30, 7.45]7% [0%, 20%]7%18%-0.01+0.602026-08-03 → 2026-08-30
tmax00Znearest30d28 1 QC5.06 [3.62, 6.54]2.16-5.06 [-6.54, -3.62]5.70 [4.25, 7.04]7% [0%, 17%]14%21%+0.06+0.602026-08-03 → 2026-08-30
tmax00Znearest90d28 1 QC5.06 [3.44, 6.70]2.16-5.06 [-6.70, -3.44]5.70 [4.07, 7.18]7% [0%, 18%]14%21%+0.06+0.602026-08-03 → 2026-08-30
tmax00Znearest365d28 1 QC5.06 [3.46, 6.83]2.16-5.06 [-6.83, -3.46]5.70 [4.10, 7.27]7% [0%, 19%]14%21%+0.06+0.602026-08-03 → 2026-08-30
tmax00Znearestall28 1 QC5.06 [3.32, 6.72]2.16-5.06 [-6.72, -3.32]5.70 [3.96, 7.21]7% [0%, 20%]14%21%+0.06+0.602026-08-03 → 2026-08-30
tmax12Zbilinear30d28 1 QC5.24 [3.99, 6.42]1.93-5.24 [-6.42, -3.99]5.74 [4.59, 6.82]7% [0%, 17%]7%18%+0.02+0.642026-08-03 → 2026-08-30
tmax12Zbilinear90d28 1 QC5.24 [3.82, 6.50]1.93-5.24 [-6.50, -3.82]5.74 [4.45, 6.87]7% [0%, 18%]7%18%+0.02+0.642026-08-03 → 2026-08-30
tmax12Zbilinear365d28 1 QC5.24 [3.85, 6.64]1.93-5.24 [-6.64, -3.85]5.74 [4.45, 6.98]7% [0%, 19%]7%18%+0.02+0.642026-08-03 → 2026-08-30
tmax12Zbilinearall28 1 QC5.24 [3.71, 6.53]1.93-5.24 [-6.53, -3.71]5.74 [4.37, 6.84]7% [0%, 20%]7%18%+0.02+0.642026-08-03 → 2026-08-30
tmax12Znearest30d28 1 QC4.94 [3.72, 6.14]1.95-4.90 [-6.13, -3.62]5.45 [4.27, 6.55]7% [0%, 17%]11%21%+0.08+0.642026-08-03 → 2026-08-30
tmax12Znearest90d28 1 QC4.94 [3.54, 6.24]1.95-4.90 [-6.23, -3.43]5.45 [4.11, 6.62]7% [0%, 18%]11%21%+0.08+0.642026-08-03 → 2026-08-30
tmax12Znearest365d28 1 QC4.94 [3.60, 6.33]1.95-4.90 [-6.33, -3.51]5.45 [4.14, 6.71]7% [0%, 19%]11%21%+0.08+0.642026-08-03 → 2026-08-30
tmax12Znearestall28 1 QC4.94 [3.46, 6.25]1.95-4.90 [-6.25, -3.34]5.45 [4.06, 6.59]7% [0%, 20%]11%21%+0.08+0.642026-08-03 → 2026-08-30
tmin00Zbilinear30d28 1 QC1.40 [1.11, 1.75]1.17-0.82 [-1.64, -0.02]1.70 [1.38, 2.05]43% [28%, 57%]68%93%+0.27+0.402026-08-03 → 2026-08-30
tmin00Zbilinear90d28 1 QC1.40 [1.08, 1.84]1.17-0.82 [-1.80, -0.02]1.70 [1.34, 2.12]43% [26%, 59%]68%93%+0.27+0.402026-08-03 → 2026-08-30
tmin00Zbilinear365d28 1 QC1.40 [1.09, 1.81]1.17-0.82 [-1.72, 0.09]1.70 [1.34, 2.07]43% [23%, 59%]68%93%+0.27+0.402026-08-03 → 2026-08-30
tmin00Zbilinearall28 1 QC1.40 [1.08, 1.86]1.17-0.82 [-1.83, 0.02]1.70 [1.35, 2.13]43% [23%, 58%]68%93%+0.27+0.402026-08-03 → 2026-08-30
tmin00Znearest30d28 1 QC1.42 [1.08, 1.81]1.24-0.75 [-1.65, 0.11]1.73 [1.37, 2.11]43% [23%, 59%]75%93%+0.26+0.362026-08-03 → 2026-08-30
tmin00Znearest90d28 1 QC1.42 [1.03, 1.90]1.24-0.75 [-1.80, 0.10]1.73 [1.31, 2.18]43% [18%, 60%]75%93%+0.26+0.362026-08-03 → 2026-08-30
tmin00Znearest365d28 1 QC1.42 [1.04, 1.87]1.24-0.75 [-1.73, 0.20]1.73 [1.33, 2.15]43% [19%, 59%]75%93%+0.26+0.362026-08-03 → 2026-08-30
tmin00Znearestall28 1 QC1.42 [1.05, 1.91]1.24-0.75 [-1.85, 0.13]1.73 [1.33, 2.19]43% [15%, 59%]75%93%+0.26+0.362026-08-03 → 2026-08-30
tmin12Zbilinear30d28 1 QC1.46 [1.14, 1.82]1.17-0.91 [-1.72, -0.08]1.77 [1.43, 2.09]32% [14%, 47%]71%89%+0.24+0.402026-08-03 → 2026-08-30
tmin12Zbilinear90d28 1 QC1.46 [1.12, 1.89]1.17-0.91 [-1.86, -0.10]1.77 [1.38, 2.16]32% [12%, 50%]71%89%+0.24+0.402026-08-03 → 2026-08-30
tmin12Zbilinear365d28 1 QC1.46 [1.11, 1.87]1.17-0.91 [-1.81, 0.00]1.77 [1.37, 2.12]32% [12%, 50%]71%89%+0.24+0.402026-08-03 → 2026-08-30
tmin12Zbilinearall28 1 QC1.46 [1.12, 1.89]1.17-0.91 [-1.87, -0.06]1.77 [1.40, 2.14]32% [9%, 50%]71%89%+0.24+0.402026-08-03 → 2026-08-30
tmin12Znearest30d28 1 QC1.49 [1.11, 1.89]1.27-0.87 [-1.74, 0.03]1.82 [1.44, 2.17]32% [14%, 47%]71%86%+0.23+0.352026-08-03 → 2026-08-30
tmin12Znearest90d28 1 QC1.49 [1.07, 1.99]1.27-0.87 [-1.89, 0.00]1.82 [1.37, 2.24]32% [12%, 50%]71%86%+0.23+0.352026-08-03 → 2026-08-30
tmin12Znearest365d28 1 QC1.49 [1.06, 1.98]1.27-0.87 [-1.86, 0.11]1.82 [1.37, 2.22]32% [12%, 50%]71%86%+0.23+0.352026-08-03 → 2026-08-30
tmin12Znearestall28 1 QC1.49 [1.08, 1.97]1.27-0.87 [-1.93, 0.05]1.82 [1.37, 2.23]32% [9%, 50%]71%86%+0.23+0.352026-08-03 → 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 2, 00Z bilinear tmax+20+100-10-202026-08-03: -2.58 °F2026-08-04: -0.52 °F2026-08-05: -3.24 °F2026-08-06: -4.02 °F2026-08-07: -7.96 °F2026-08-08: -6.72 °F2026-08-09: -3.88 °F2026-08-10: -0.58 °F2026-08-11: -4.49 °F2026-08-12: -6.03 °F2026-08-13: -5.41 °F2026-08-14: -4.61 °F2026-08-15: -2.3 °F2026-08-16: -3.78 °F2026-08-17: -7.8 °F2026-08-18: -9.36 °F2026-08-19: -10.3 °F2026-08-20: -8.54 °F2026-08-21: -9.12 °F2026-08-22: -8.34 °F2026-08-23: -5.28 °F2026-08-24: -6.21 °F2026-08-25: -6.76 °F2026-08-26: -3.66 °F2026-08-27: -5.55 °F2026-08-28: -4.98 °F2026-08-29: -7.24 °F2026-08-30: -2.01 °F2026-08-032026-08-30°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 (28 days, newest first) · download CSV
Climatological dayError °F
2026-08-30-2.01
2026-08-29-7.24
2026-08-28-4.98
2026-08-27-5.55
2026-08-26-3.66
2026-08-25-6.76
2026-08-24-6.21
2026-08-23-5.28
2026-08-22-8.34
2026-08-21-9.12
2026-08-20-8.54
2026-08-19-10.30
2026-08-18-9.36
2026-08-17-7.80
2026-08-16-3.78
2026-08-15-2.30
2026-08-14-4.61
2026-08-13-5.41
2026-08-12-6.03
2026-08-11-4.49
2026-08-10-0.58
2026-08-09-3.88
2026-08-08-6.72
2026-08-07-7.96
2026-08-06-4.02
2026-08-05-3.24
2026-08-04-0.52
2026-08-03-2.58

Error distribution

Distribution of the signed daily error in °F for ECMWF AIFS Single at KSEA, lead day 2-20 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: 1 day-10 to -8 °F: 4 days-8 to -6 °F: 7 days-6 to -4 °F: 7 days-4 to -2 °F: 7 days-2 to 0 °F: 2 days0 to 2 °F: 0 days2 to 4 °F: 0 days4 to 6 °F: 0 days6 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| 5.34 · P90 |e| 8.71 °F-200+20 °Fn = 28 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
-12.00-10.001
-10.00-8.004
-8.00-6.007
-6.00-4.007
-4.00-2.007
-2.00+0.002
+0.00+2.000
+2.00+4.000
+4.00+6.000
+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
2026-08285.40 -5.40

Availability

ModelScored period DaysCoverage
ECMWF AIFS Single2026-08-03 → 2026-08-30 28
ECMWF AIFS Single2026-08-03 → 2026-08-30 28
ECMWF AIFS Single2026-08-03 → 2026-08-30 28
ECMWF AIFS Single2026-08-03 → 2026-08-30 28

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 (IFS init) 1 -0.37 [-0.37, -0.37] yes
FourCastNet v2 (IFS init) 1 +0.49 [0.49, 0.49] yes
NCEP GFS 28 +1.00 [-0.84, 3.07] no
GraphCast (IFS init) 26 +0.66 [-0.17, 1.16] no
ECMWF IFS HRES 23 +3.22 [1.75, 4.35] yes
Pangu-Weather (IFS init) 1 -0.27 [-0.27, -0.27] yes
Persistence (baseline) 28 +0.05 [-2.45, 2.02] no

Cite this page

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

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

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