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

Boston Logan · ECMWF AIFS Single · lead day 4

KBOS · aifs_single · 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, 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
tmax00Zbilinear30d25 1 QC4.26 [3.71, 4.79]3.83-2.28 [-4.08, -0.51]5.07 [4.47, 5.58]12% [0%, 24%]28%44%+0.36+0.422026-08-05 → 2026-08-30
tmax00Zbilinear90d25 1 QC4.26 [3.67, 4.90]3.83-2.28 [-4.38, -0.46]5.07 [4.42, 5.70]12% [0%, 26%]28%44%+0.36+0.422026-08-05 → 2026-08-30
tmax00Zbilinear365d25 1 QC4.26 [3.62, 4.92]3.83-2.28 [-4.39, -0.10]5.07 [4.26, 5.68]12% [0%, 25%]28%44%+0.36+0.422026-08-05 → 2026-08-30
tmax00Zbilinearall25 1 QC4.26 [3.61, 4.90]3.83-2.28 [-4.45, -0.34]5.07 [4.27, 5.68]12% [0%, 25%]28%44%+0.36+0.422026-08-05 → 2026-08-30
tmax00Znearest30d25 1 QC4.23 [3.66, 4.80]3.80-2.33 [-4.20, -0.59]5.06 [4.41, 5.63]12% [0%, 24%]36%44%+0.37+0.432026-08-05 → 2026-08-30
tmax00Znearest90d25 1 QC4.23 [3.62, 4.92]3.80-2.33 [-4.52, -0.52]5.06 [4.35, 5.75]12% [0%, 26%]36%44%+0.37+0.432026-08-05 → 2026-08-30
tmax00Znearest365d25 1 QC4.23 [3.53, 4.92]3.80-2.33 [-4.47, -0.18]5.06 [4.21, 5.73]12% [0%, 25%]36%44%+0.37+0.432026-08-05 → 2026-08-30
tmax00Znearestall25 1 QC4.23 [3.53, 4.92]3.80-2.33 [-4.57, -0.41]5.06 [4.20, 5.72]12% [0%, 25%]36%44%+0.37+0.432026-08-05 → 2026-08-30
tmax12Zbilinear30d25 1 QC4.16 [3.39, 4.88]3.69-2.22 [-3.96, -0.52]4.88 [4.10, 5.50]12% [0%, 29%]28%40%+0.38+0.452026-08-05 → 2026-08-30
tmax12Zbilinear90d25 1 QC4.16 [3.36, 5.00]3.69-2.22 [-4.26, -0.54]4.88 [4.12, 5.59]12% [0%, 33%]28%40%+0.38+0.452026-08-05 → 2026-08-30
tmax12Zbilinear365d25 1 QC4.16 [3.25, 5.04]3.69-2.22 [-4.18, -0.14]4.88 [3.91, 5.60]12% [0%, 33%]28%40%+0.38+0.452026-08-05 → 2026-08-30
tmax12Zbilinearall25 1 QC4.16 [3.30, 5.08]3.69-2.22 [-4.21, -0.47]4.88 [3.99, 5.66]12% [0%, 33%]28%40%+0.38+0.452026-08-05 → 2026-08-30
tmax12Znearest30d25 1 QC4.09 [3.28, 4.84]3.63-2.22 [-3.97, -0.59]4.82 [4.00, 5.50]8% [0%, 24%]32%40%+0.39+0.462026-08-05 → 2026-08-30
tmax12Znearest90d25 1 QC4.09 [3.27, 4.98]3.63-2.22 [-4.35, -0.55]4.82 [4.01, 5.64]8% [0%, 26%]32%40%+0.39+0.462026-08-05 → 2026-08-30
tmax12Znearest365d25 1 QC4.09 [3.15, 4.97]3.63-2.22 [-4.21, -0.18]4.82 [3.77, 5.64]8% [0%, 33%]32%40%+0.39+0.462026-08-05 → 2026-08-30
tmax12Znearestall25 1 QC4.09 [3.17, 5.05]3.63-2.22 [-4.29, -0.47]4.82 [3.80, 5.68]8% [0%, 27%]32%40%+0.39+0.462026-08-05 → 2026-08-30
tmin00Zbilinear30d25 1 QC1.70 [1.05, 2.41]1.66-0.12 [-0.85, 0.75]2.11 [1.32, 2.76]36% [13%, 59%]68%80%+0.43+0.422026-08-05 → 2026-08-30
tmin00Zbilinear90d25 1 QC1.70 [0.87, 2.56]1.66-0.12 [-0.90, 0.78]2.11 [1.08, 2.87]36% [11%, 68%]68%80%+0.43+0.422026-08-05 → 2026-08-30
tmin00Zbilinear365d25 1 QC1.70 [0.87, 2.58]1.66-0.12 [-0.92, 0.85]2.11 [1.05, 2.88]36% [6%, 68%]68%80%+0.43+0.422026-08-05 → 2026-08-30
tmin00Zbilinearall25 1 QC1.70 [0.88, 2.56]1.66-0.12 [-1.00, 0.78]2.11 [1.05, 2.86]36% [9%, 67%]68%80%+0.43+0.422026-08-05 → 2026-08-30
tmin00Znearest30d25 1 QC1.66 [0.98, 2.43]1.69+0.15 [-0.64, 1.09]2.12 [1.28, 2.81]36% [13%, 59%]68%80%+0.44+0.412026-08-05 → 2026-08-30
tmin00Znearest90d25 1 QC1.66 [0.78, 2.56]1.69+0.15 [-0.68, 1.10]2.12 [0.96, 2.89]36% [11%, 68%]68%80%+0.44+0.412026-08-05 → 2026-08-30
tmin00Znearest365d25 1 QC1.66 [0.80, 2.60]1.69+0.15 [-0.68, 1.18]2.12 [0.97, 2.93]36% [6%, 68%]68%80%+0.44+0.412026-08-05 → 2026-08-30
tmin00Znearestall25 1 QC1.66 [0.81, 2.55]1.69+0.15 [-0.76, 1.10]2.12 [0.99, 2.89]36% [9%, 67%]68%80%+0.44+0.412026-08-05 → 2026-08-30
tmin12Zbilinear30d25 1 QC1.65 [1.11, 2.18]1.61-0.29 [-1.14, 0.64]1.98 [1.37, 2.48]28% [7%, 48%]64%84%+0.44+0.442026-08-05 → 2026-08-30
tmin12Zbilinear90d25 1 QC1.65 [1.04, 2.22]1.61-0.29 [-1.24, 0.68]1.98 [1.31, 2.50]28% [5%, 50%]64%84%+0.44+0.442026-08-05 → 2026-08-30
tmin12Zbilinear365d25 1 QC1.65 [1.05, 2.27]1.61-0.29 [-1.24, 0.78]1.98 [1.33, 2.56]28% [0%, 54%]64%84%+0.44+0.442026-08-05 → 2026-08-30
tmin12Zbilinearall25 1 QC1.65 [1.05, 2.23]1.61-0.29 [-1.35, 0.69]1.98 [1.33, 2.54]28% [0%, 52%]64%84%+0.44+0.442026-08-05 → 2026-08-30
tmin12Znearest30d25 1 QC1.63 [1.07, 2.21]1.63-0.02 [-0.93, 0.94]1.95 [1.28, 2.51]36% [17%, 56%]64%88%+0.45+0.442026-08-05 → 2026-08-30
tmin12Znearest90d25 1 QC1.63 [1.00, 2.27]1.63-0.02 [-0.99, 0.97]1.95 [1.22, 2.55]36% [15%, 59%]64%88%+0.45+0.442026-08-05 → 2026-08-30
tmin12Znearest365d25 1 QC1.63 [1.00, 2.31]1.63-0.02 [-1.02, 1.10]1.95 [1.23, 2.61]36% [14%, 60%]64%88%+0.45+0.442026-08-05 → 2026-08-30
tmin12Znearestall25 1 QC1.63 [1.00, 2.29]1.63-0.02 [-1.14, 1.02]1.95 [1.23, 2.56]36% [14%, 58%]64%88%+0.45+0.442026-08-05 → 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 AIFS Single at KBOS, lead day 4, 00Z bilinear tmax+10+50-5-102026-08-05: -7.07 °F2026-08-06: -0.85 °F2026-08-07: -7.54 °F2026-08-08: -7.17 °F2026-08-09: -2.17 °F2026-08-10: +0.89 °F2026-08-11: -9.06 °F2026-08-12: -1.98 °F2026-08-13: -5.03 °F2026-08-14: -4.42 °F2026-08-15: +2.08 °F2026-08-16: -1.44 °F2026-08-17: +7.7 °F2026-08-18: +2.34 °F2026-08-19: -9.11 °F2026-08-20: -3.1 °F2026-08-21: +6.23 °F2026-08-22: +1.57 °F2026-08-23: +1.76 °F2026-08-24: -6.9 °F2026-08-25: -6.01 °F2026-08-26: +0.07 °F2026-08-27: -5.93 °F2026-08-29: +2.06 °F2026-08-30: -3.96 °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
2026-08-30-3.96
2026-08-29+2.06
2026-08-28—
2026-08-27-5.93
2026-08-26+0.07
2026-08-25-6.01
2026-08-24-6.90
2026-08-23+1.76
2026-08-22+1.57
2026-08-21+6.23
2026-08-20-3.10
2026-08-19-9.11
2026-08-18+2.34
2026-08-17+7.70
2026-08-16-1.44
2026-08-15+2.08
2026-08-14-4.42
2026-08-13-5.03
2026-08-12-1.98
2026-08-11-9.06
2026-08-10+0.89
2026-08-09-2.17
2026-08-08-7.17
2026-08-07-7.54
2026-08-06-0.85
2026-08-05-7.07

Error distribution

Distribution of the signed daily error in °F for ECMWF AIFS Single at KBOS, lead day 4-10 to -9 °F: 2 days-9 to -8 °F: 0 days-8 to -7 °F: 3 days-7 to -6 °F: 2 days-6 to -5 °F: 2 days-5 to -4 °F: 1 day-4 to -3 °F: 2 days-3 to -2 °F: 1 day-2 to -1 °F: 2 days-1 to 0 °F: 1 day0 to 1 °F: 2 days1 to 2 °F: 2 days2 to 3 °F: 3 days3 to 4 °F: 0 days4 to 5 °F: 0 days5 to 6 °F: 0 days6 to 7 °F: 1 day7 to 8 °F: 1 day8 to 9 °F: 0 days9 to 10 °F: 0 daysdashed: P50 |e| 3.96 · P90 |e| 7.64 °F-100+10 °Fn = 25 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
-9.00-8.000
-8.00-7.003
-7.00-6.002
-6.00-5.002
-5.00-4.001
-4.00-3.002
-3.00-2.001
-2.00-1.002
-1.00+0.001
+0.00+1.002
+1.00+2.002
+2.00+3.003
+3.00+4.000
+4.00+5.000
+5.00+6.000
+6.00+7.001
+7.00+8.001
+8.00+9.000
+9.00+10.000

Month by month

00Z bilinear daily maximum, newest first.

Monthn MAE °FBias °F
2026-08254.26 -2.28

Availability

ModelScored period DaysCoverage
ECMWF AIFS Single2026-08-05 → 2026-08-30 25
ECMWF AIFS Single2026-08-05 → 2026-08-30 25
ECMWF AIFS Single2026-08-05 → 2026-08-30 25
ECMWF AIFS Single2026-08-05 → 2026-08-30 25

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 25 +0.05 [-1.11, 1.46] no
GraphCast (IFS init) 24 -0.16 [-1.01, 0.62] no
ECMWF IFS HRES 19 +0.70 [-0.40, 1.70] no
Persistence (baseline) 25 -2.42 [-4.39, -0.10] yes

Cite this page

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

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