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

Boston Logan · ECMWF AIFS Single · lead day 8

KBOS · aifs_single · lead 8

Target day = initialization date + 8 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 QC5.44 [4.47, 6.50]4.45-3.11 [-5.74, -0.90]6.14 [5.08, 7.17]5% [0%, 12%]19%19%+0.18+0.322026-08-09 → 2026-08-30
tmax00Zbilinear90d21 1 QC5.44 [4.48, 6.56]4.45-3.11 [-5.97, -0.90]6.14 [5.10, 7.24]5% [0%, 13%]19%19%+0.18+0.322026-08-09 → 2026-08-30
tmax00Zbilinear365d21 1 QC5.44 [4.39, 6.60]4.45-3.11 [-6.03, -0.27]6.14 [5.01, 7.32]5% [0%, 14%]19%19%+0.18+0.322026-08-09 → 2026-08-30
tmax00Zbilinearall21 1 QC5.44 [4.39, 6.62]4.45-3.11 [-5.94, -0.90]6.14 [4.94, 7.34]5% [0%, 14%]19%19%+0.18+0.322026-08-09 → 2026-08-30
tmax00Znearest30d21 1 QC5.41 [4.43, 6.48]4.42-3.13 [-5.78, -0.92]6.13 [5.05, 7.17]5% [0%, 12%]19%19%+0.19+0.332026-08-09 → 2026-08-30
tmax00Znearest90d21 1 QC5.41 [4.46, 6.57]4.42-3.13 [-6.02, -0.90]6.13 [5.08, 7.26]5% [0%, 13%]19%19%+0.19+0.332026-08-09 → 2026-08-30
tmax00Znearest365d21 1 QC5.41 [4.35, 6.58]4.42-3.13 [-6.07, -0.31]6.13 [4.99, 7.31]5% [0%, 14%]19%19%+0.19+0.332026-08-09 → 2026-08-30
tmax00Znearestall21 1 QC5.41 [4.36, 6.58]4.42-3.13 [-6.00, -0.91]6.13 [4.92, 7.30]5% [0%, 14%]19%19%+0.19+0.332026-08-09 → 2026-08-30
tmax12Zbilinear30d21 1 QC4.67 [4.03, 5.59]3.81-3.12 [-4.93, -1.75]5.62 [4.81, 6.55]10% [0%, 22%]24%38%+0.30+0.422026-08-09 → 2026-08-30
tmax12Zbilinear90d21 1 QC4.67 [3.96, 5.67]3.81-3.12 [-5.27, -1.64]5.62 [4.75, 6.71]10% [0%, 24%]24%38%+0.30+0.422026-08-09 → 2026-08-30
tmax12Zbilinear365d21 1 QC4.67 [3.93, 5.63]3.81-3.12 [-5.52, -1.51]5.62 [4.75, 6.65]10% [0%, 23%]24%38%+0.30+0.422026-08-09 → 2026-08-30
tmax12Zbilinearall21 1 QC4.67 [3.96, 5.90]3.81-3.12 [-5.74, -1.50]5.62 [4.75, 6.88]10% [0%, 24%]24%38%+0.30+0.422026-08-09 → 2026-08-30
tmax12Znearest30d21 1 QC4.62 [3.96, 5.58]3.82-3.12 [-4.99, -1.75]5.62 [4.79, 6.56]10% [0%, 22%]33%43%+0.31+0.422026-08-09 → 2026-08-30
tmax12Znearest90d21 1 QC4.62 [3.90, 5.67]3.82-3.12 [-5.28, -1.63]5.62 [4.70, 6.70]10% [0%, 24%]33%43%+0.31+0.422026-08-09 → 2026-08-30
tmax12Znearest365d21 1 QC4.62 [3.84, 5.60]3.82-3.12 [-5.57, -1.51]5.62 [4.69, 6.68]10% [0%, 23%]33%43%+0.31+0.422026-08-09 → 2026-08-30
tmax12Znearestall21 1 QC4.62 [3.90, 5.89]3.82-3.12 [-5.79, -1.51]5.62 [4.69, 6.92]10% [0%, 24%]33%43%+0.31+0.422026-08-09 → 2026-08-30
tmin00Zbilinear30d21 1 QC2.23 [1.59, 2.99]2.08-0.66 [-2.33, 0.73]2.79 [2.00, 3.74]19% [3%, 43%]52%81%+0.44+0.432026-08-09 → 2026-08-30
tmin00Zbilinear90d21 1 QC2.23 [1.46, 3.04]2.08-0.66 [-2.79, 0.90]2.79 [1.83, 3.82]19% [0%, 50%]52%81%+0.44+0.432026-08-09 → 2026-08-30
tmin00Zbilinear365d21 1 QC2.23 [1.45, 3.03]2.08-0.66 [-2.74, 1.09]2.79 [1.83, 3.88]19% [0%, 50%]52%81%+0.44+0.432026-08-09 → 2026-08-30
tmin00Zbilinearall21 1 QC2.23 [1.46, 3.24]2.08-0.66 [-2.95, 0.92]2.79 [1.83, 4.16]19% [0%, 50%]52%81%+0.44+0.432026-08-09 → 2026-08-30
tmin00Znearest30d21 1 QC2.12 [1.49, 2.88]2.03-0.43 [-2.08, 0.96]2.73 [1.81, 3.63]24% [4%, 47%]52%86%+0.47+0.442026-08-09 → 2026-08-30
tmin00Znearest90d21 1 QC2.12 [1.39, 2.92]2.03-0.43 [-2.55, 1.14]2.73 [1.75, 3.75]24% [4%, 50%]52%86%+0.47+0.442026-08-09 → 2026-08-30
tmin00Znearest365d21 1 QC2.12 [1.39, 2.93]2.03-0.43 [-2.49, 1.32]2.73 [1.75, 3.72]24% [0%, 52%]52%86%+0.47+0.442026-08-09 → 2026-08-30
tmin00Znearestall21 1 QC2.12 [1.39, 3.20]2.03-0.43 [-2.70, 1.17]2.73 [1.73, 4.00]24% [0%, 50%]52%86%+0.47+0.442026-08-09 → 2026-08-30
tmin12Zbilinear30d21 1 QC2.16 [1.64, 2.80]2.11-0.32 [-1.28, 0.56]2.72 [2.20, 3.29]33% [18%, 48%]57%67%+0.46+0.422026-08-09 → 2026-08-30
tmin12Zbilinear90d21 1 QC2.16 [1.62, 2.76]2.11-0.32 [-1.60, 0.73]2.72 [2.18, 3.31]33% [18%, 50%]57%67%+0.46+0.422026-08-09 → 2026-08-30
tmin12Zbilinear365d21 1 QC2.16 [1.59, 3.02]2.11-0.32 [-1.63, 0.72]2.72 [2.20, 3.50]33% [14%, 50%]57%67%+0.46+0.422026-08-09 → 2026-08-30
tmin12Zbilinearall21 1 QC2.16 [1.64, 2.82]2.11-0.32 [-1.99, 0.58]2.72 [2.22, 3.50]33% [17%, 50%]57%67%+0.46+0.422026-08-09 → 2026-08-30
tmin12Znearest30d21 1 QC2.07 [1.54, 2.71]2.06-0.06 [-0.97, 0.78]2.61 [2.08, 3.18]43% [22%, 69%]57%67%+0.48+0.432026-08-09 → 2026-08-30
tmin12Znearest90d21 1 QC2.07 [1.51, 2.70]2.06-0.06 [-1.27, 0.91]2.61 [2.04, 3.20]43% [19%, 71%]57%67%+0.48+0.432026-08-09 → 2026-08-30
tmin12Znearest365d21 1 QC2.07 [1.47, 2.91]2.06-0.06 [-1.32, 0.93]2.61 [2.01, 3.31]43% [15%, 75%]57%67%+0.48+0.432026-08-09 → 2026-08-30
tmin12Znearestall21 1 QC2.07 [1.53, 2.72]2.06-0.06 [-1.64, 0.81]2.61 [2.09, 3.21]43% [19%, 73%]57%67%+0.48+0.432026-08-09 → 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 KBOS, lead day 8, 00Z bilinear tmax+20+100-10-202026-08-09: -4.44 °F2026-08-10: -6.74 °F2026-08-11: -6.82 °F2026-08-12: -5.66 °F2026-08-13: -3.54 °F2026-08-14: -5.64 °F2026-08-15: +0.6 °F2026-08-16: -4.67 °F2026-08-17: +1.21 °F2026-08-18: +6.34 °F2026-08-19: -9.24 °F2026-08-20: -3.59 °F2026-08-21: +4.11 °F2026-08-22: +4.76 °F2026-08-23: +7.41 °F2026-08-24: -11.04 °F2026-08-25: -8.17 °F2026-08-26: -1.44 °F2026-08-27: -8.8 °F2026-08-29: -1.1 °F2026-08-30: -8.83 °F2026-08-092026-08-30°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 (22 days, newest first) · download CSV
Climatological dayError °F
2026-08-30-8.83
2026-08-29-1.10
2026-08-28—
2026-08-27-8.80
2026-08-26-1.44
2026-08-25-8.17
2026-08-24-11.04
2026-08-23+7.41
2026-08-22+4.76
2026-08-21+4.11
2026-08-20-3.59
2026-08-19-9.24
2026-08-18+6.34
2026-08-17+1.21
2026-08-16-4.67
2026-08-15+0.60
2026-08-14-5.64
2026-08-13-3.54
2026-08-12-5.66
2026-08-11-6.82
2026-08-10-6.74
2026-08-09-4.44

Error distribution

Distribution of the signed daily error in °F for ECMWF AIFS Single at KBOS, lead day 8-20 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: 2 days-6 to -4 °F: 4 days-4 to -2 °F: 2 days-2 to 0 °F: 2 days0 to 2 °F: 2 days2 to 4 °F: 0 days4 to 6 °F: 2 days6 to 8 °F: 2 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| 5.64 · P90 |e| 8.83 °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
-12.00-10.001
-10.00-8.004
-8.00-6.002
-6.00-4.004
-4.00-2.002
-2.00+0.002
+0.00+2.002
+2.00+4.000
+4.00+6.002
+6.00+8.002
+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
2026-08215.44 -3.11

Availability

ModelScored period DaysCoverage
ECMWF AIFS Single2026-08-09 → 2026-08-30 21
ECMWF AIFS Single2026-08-09 → 2026-08-30 21
ECMWF AIFS Single2026-08-09 → 2026-08-30 21
ECMWF AIFS Single2026-08-09 → 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 -1.01 [-2.29, 0.37] no
GraphCast (IFS init) 21 +0.06 [-1.65, 2.36] no
ECMWF IFS HRES 16 -1.17 [-5.91, 1.81] no
Persistence (baseline) 21 -1.23 [-3.94, 1.41] no

Cite this page

ShortCastCheck, KBOS aifs_single lead 8, methodology v0.2, accessed 2026-08-31, https://castcheck.zifanzhang.com/station/KBOS/model/aifs_single/lead/8/

LongCastCheck (2026). Station-level verification of raw weather-model 2 m temperature forecasts: KBOS (Boston Logan), model aifs_single, lead day 8. Methodology version 0.2, schema version 0.1, data through 2026-08-30. Accessed 2026-08-31. https://castcheck.zifanzhang.com/station/KBOS/model/aifs_single/lead/8/

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

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