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

Boston Logan · ECMWF AIFS Single · lead day 9

KBOS · aifs_single · lead 9

Target day = initialization date + 9 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
tmax00Zbilinear30d20 1 QC6.27 [5.15, 7.44]5.63-3.41 [-6.47, -0.41]7.44 [6.33, 8.55]10% [0%, 22%]25%30%+0.21+0.282026-08-10 → 2026-08-30
tmax00Zbilinear90d20 1 QC6.27 [5.12, 7.53]5.63-3.41 [-6.70, -0.13]7.44 [6.23, 8.67]10% [0%, 23%]25%30%+0.21+0.282026-08-10 → 2026-08-30
tmax00Zbilinear365d20 1 QC6.27 [5.05, 7.55]5.63-3.41 [-6.69, 0.12]7.44 [6.21, 8.65]10% [0%, 25%]25%30%+0.21+0.282026-08-10 → 2026-08-30
tmax00Zbilinearall20 1 QC6.27 [5.11, 7.51]5.63-3.41 [-6.82, 0.36]7.44 [6.27, 8.69]10% [0%, 23%]25%30%+0.21+0.282026-08-10 → 2026-08-30
tmax00Znearest30d20 1 QC6.24 [5.12, 7.42]5.54-3.43 [-6.49, -0.42]7.40 [6.24, 8.55]10% [0%, 22%]25%30%+0.22+0.292026-08-10 → 2026-08-30
tmax00Znearest90d20 1 QC6.24 [5.02, 7.52]5.54-3.43 [-6.74, -0.14]7.40 [6.15, 8.75]10% [0%, 23%]25%30%+0.22+0.292026-08-10 → 2026-08-30
tmax00Znearest365d20 1 QC6.24 [5.01, 7.57]5.54-3.43 [-6.73, 0.10]7.40 [6.15, 8.62]10% [0%, 25%]25%30%+0.22+0.292026-08-10 → 2026-08-30
tmax00Znearestall20 1 QC6.24 [5.07, 7.49]5.54-3.43 [-6.82, 0.29]7.40 [6.18, 8.68]10% [0%, 23%]25%30%+0.22+0.292026-08-10 → 2026-08-30
tmax12Zbilinear30d20 1 QC5.24 [3.95, 7.15]4.32-4.02 [-6.77, -1.87]6.49 [4.94, 8.76]10% [0%, 24%]25%40%+0.34+0.452026-08-10 → 2026-08-30
tmax12Zbilinear90d20 1 QC5.24 [3.65, 7.35]4.32-4.02 [-7.35, -1.57]6.49 [4.50, 9.15]10% [0%, 27%]25%40%+0.34+0.452026-08-10 → 2026-08-30
tmax12Zbilinear365d20 1 QC5.24 [3.64, 7.39]4.32-4.02 [-7.39, -1.38]6.49 [4.48, 9.16]10% [0%, 25%]25%40%+0.34+0.452026-08-10 → 2026-08-30
tmax12Zbilinearall20 1 QC5.24 [3.72, 7.89]4.32-4.02 [-7.87, -1.81]6.49 [4.64, 9.75]10% [0%, 25%]25%40%+0.34+0.452026-08-10 → 2026-08-30
tmax12Znearest30d20 1 QC5.25 [3.95, 7.23]4.31-4.04 [-6.86, -1.89]6.52 [4.96, 8.85]5% [0%, 20%]30%35%+0.34+0.452026-08-10 → 2026-08-30
tmax12Znearest90d20 1 QC5.25 [3.65, 7.44]4.31-4.04 [-7.44, -1.60]6.52 [4.54, 9.27]5% [0%, 25%]30%35%+0.34+0.452026-08-10 → 2026-08-30
tmax12Znearest365d20 1 QC5.25 [3.63, 7.49]4.31-4.04 [-7.49, -1.39]6.52 [4.47, 9.26]5% [0%, 22%]30%35%+0.34+0.452026-08-10 → 2026-08-30
tmax12Znearestall20 1 QC5.25 [3.78, 7.98]4.31-4.04 [-7.98, -1.82]6.52 [4.62, 9.87]5% [0%, 24%]30%35%+0.34+0.452026-08-10 → 2026-08-30
tmin00Zbilinear30d20 1 QC3.11 [2.19, 4.47]3.05-0.51 [-2.17, 0.95]3.76 [2.75, 4.99]20% [0%, 38%]30%55%+0.22+0.212026-08-10 → 2026-08-30
tmin00Zbilinear90d20 1 QC3.11 [2.22, 4.91]3.05-0.51 [-2.25, 1.28]3.76 [2.76, 5.35]20% [0%, 36%]30%55%+0.22+0.212026-08-10 → 2026-08-30
tmin00Zbilinear365d20 1 QC3.11 [2.04, 4.78]3.05-0.51 [-2.33, 1.23]3.76 [2.55, 5.20]20% [0%, 40%]30%55%+0.22+0.212026-08-10 → 2026-08-30
tmin00Zbilinearall20 1 QC3.11 [2.09, 5.28]3.05-0.51 [-2.49, 0.99]3.76 [2.51, 5.71]20% [0%, 38%]30%55%+0.22+0.212026-08-10 → 2026-08-30
tmin00Znearest30d20 1 QC3.02 [2.14, 4.27]2.99-0.26 [-1.89, 1.20]3.63 [2.65, 4.78]20% [0%, 36%]25%55%+0.25+0.222026-08-10 → 2026-08-30
tmin00Znearest90d20 1 QC3.02 [2.18, 4.71]2.99-0.26 [-1.98, 1.50]3.63 [2.66, 5.12]20% [0%, 36%]25%55%+0.25+0.222026-08-10 → 2026-08-30
tmin00Znearest365d20 1 QC3.02 [1.99, 4.60]2.99-0.26 [-2.01, 1.47]3.63 [2.46, 4.96]20% [0%, 38%]25%55%+0.25+0.222026-08-10 → 2026-08-30
tmin00Znearestall20 1 QC3.02 [2.01, 5.05]2.99-0.26 [-2.16, 1.21]3.63 [2.43, 5.42]20% [0%, 36%]25%55%+0.25+0.222026-08-10 → 2026-08-30
tmin12Zbilinear30d20 1 QC2.83 [2.20, 4.01]2.78-0.57 [-3.00, 1.17]3.53 [2.56, 5.16]20% [7%, 32%]45%55%+0.29+0.282026-08-10 → 2026-08-30
tmin12Zbilinear90d20 1 QC2.83 [2.18, 4.43]2.78-0.57 [-3.83, 1.44]3.53 [2.54, 5.67]20% [0%, 33%]45%55%+0.29+0.282026-08-10 → 2026-08-30
tmin12Zbilinear365d20 1 QC2.83 [2.06, 4.39]2.78-0.57 [-4.00, 1.57]3.53 [2.48, 5.49]20% [0%, 33%]45%55%+0.29+0.282026-08-10 → 2026-08-30
tmin12Zbilinearall20 1 QC2.83 [2.06, 5.03]2.78-0.57 [-4.56, 1.15]3.53 [2.43, 6.18]20% [0%, 36%]45%55%+0.29+0.282026-08-10 → 2026-08-30
tmin12Znearest30d20 1 QC2.74 [2.10, 3.81]2.71-0.28 [-2.63, 1.39]3.39 [2.45, 4.86]10% [0%, 25%]45%65%+0.32+0.302026-08-10 → 2026-08-30
tmin12Znearest90d20 1 QC2.74 [2.05, 4.10]2.71-0.28 [-3.42, 1.67]3.39 [2.43, 5.22]10% [0%, 25%]45%65%+0.32+0.302026-08-10 → 2026-08-30
tmin12Znearest365d20 1 QC2.74 [2.00, 4.08]2.71-0.28 [-3.61, 1.81]3.39 [2.29, 5.10]10% [0%, 26%]45%65%+0.32+0.302026-08-10 → 2026-08-30
tmin12Znearestall20 1 QC2.74 [1.97, 4.65]2.71-0.28 [-4.13, 1.39]3.39 [2.25, 5.73]10% [0%, 26%]45%65%+0.32+0.302026-08-10 → 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 9, 00Z bilinear tmax+20+100-10-202026-08-10: +1.48 °F2026-08-11: -13.72 °F2026-08-12: -7.3 °F2026-08-13: -8.41 °F2026-08-14: -8.49 °F2026-08-15: +0.34 °F2026-08-16: -7.77 °F2026-08-17: -6.37 °F2026-08-18: -0.08 °F2026-08-19: -8.14 °F2026-08-20: -9.36 °F2026-08-21: +12.03 °F2026-08-22: +3.32 °F2026-08-23: +8.78 °F2026-08-24: -1.39 °F2026-08-25: -7.87 °F2026-08-26: -1.45 °F2026-08-27: -4.72 °F2026-08-29: +2.58 °F2026-08-30: -11.73 °F2026-08-102026-08-30°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 (21 days, newest first) · download CSV
Climatological dayError °F
2026-08-30-11.73
2026-08-29+2.58
2026-08-28—
2026-08-27-4.72
2026-08-26-1.45
2026-08-25-7.87
2026-08-24-1.39
2026-08-23+8.78
2026-08-22+3.32
2026-08-21+12.03
2026-08-20-9.36
2026-08-19-8.14
2026-08-18-0.08
2026-08-17-6.37
2026-08-16-7.77
2026-08-15+0.34
2026-08-14-8.49
2026-08-13-8.41
2026-08-12-7.30
2026-08-11-13.72
2026-08-10+1.48

Error distribution

Distribution of the signed daily error in °F for ECMWF AIFS Single at KBOS, lead day 9-20 to -18 °F: 0 days-18 to -16 °F: 0 days-16 to -14 °F: 0 days-14 to -12 °F: 1 day-12 to -10 °F: 1 day-10 to -8 °F: 4 days-8 to -6 °F: 4 days-6 to -4 °F: 1 day-4 to -2 °F: 0 days-2 to 0 °F: 3 days0 to 2 °F: 2 days2 to 4 °F: 2 days4 to 6 °F: 0 days6 to 8 °F: 0 days8 to 10 °F: 1 day10 to 12 °F: 0 days12 to 14 °F: 1 day14 to 16 °F: 0 days16 to 18 °F: 0 days18 to 20 °F: 0 daysdashed: P50 |e| 7.53 · P90 |e| 11.76 °F-200+20 °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
-20.00-18.000
-18.00-16.000
-16.00-14.000
-14.00-12.001
-12.00-10.001
-10.00-8.004
-8.00-6.004
-6.00-4.001
-4.00-2.000
-2.00+0.003
+0.00+2.002
+2.00+4.002
+4.00+6.000
+6.00+8.000
+8.00+10.001
+10.00+12.000
+12.00+14.001
+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
2026-08206.27 -3.41

Availability

ModelScored period DaysCoverage
ECMWF AIFS Single2026-08-10 → 2026-08-30 20
ECMWF AIFS Single2026-08-10 → 2026-08-30 20
ECMWF AIFS Single2026-08-10 → 2026-08-30 20
ECMWF AIFS Single2026-08-10 → 2026-08-30 20

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 20 -0.89 [-3.83, 0.86] no
GraphCast (IFS init) 20 +0.88 [-0.90, 2.46] no
ECMWF IFS HRES 15 +1.48 [-1.13, 2.28] no
Persistence (baseline) 20 -1.68 [-4.50, 2.71] no

Cite this page

ShortCastCheck, KBOS aifs_single lead 9, methodology v0.2, accessed 2026-08-31, https://castcheck.zifanzhang.com/station/KBOS/model/aifs_single/lead/9/

LongCastCheck (2026). Station-level verification of raw weather-model 2 m temperature forecasts: KBOS (Boston Logan), model aifs_single, lead day 9. 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/9/

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

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