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

Boston Logan · ECMWF AIFS Single · lead day 6

KBOS · aifs_single · lead 6

Target day = initialization date + 6 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
tmax00Zbilinear30d23 1 QC4.68 [3.73, 5.59]4.10-2.72 [-4.64, -0.92]5.68 [4.75, 6.45]9% [0%, 16%]22%39%+0.28+0.352026-08-07 → 2026-08-30
tmax00Zbilinear90d23 1 QC4.68 [3.80, 5.67]4.10-2.72 [-4.80, -0.99]5.68 [4.78, 6.49]9% [0%, 17%]22%39%+0.28+0.352026-08-07 → 2026-08-30
tmax00Zbilinear365d23 1 QC4.68 [3.63, 5.62]4.10-2.72 [-4.89, -0.52]5.68 [4.67, 6.44]9% [0%, 17%]22%39%+0.28+0.352026-08-07 → 2026-08-30
tmax00Zbilinearall23 1 QC4.68 [3.74, 5.79]4.10-2.72 [-4.99, -0.73]5.68 [4.72, 6.46]9% [0%, 17%]22%39%+0.28+0.352026-08-07 → 2026-08-30
tmax00Znearest30d23 1 QC4.63 [3.67, 5.55]4.05-2.69 [-4.64, -0.87]5.63 [4.71, 6.41]13% [0%, 25%]26%39%+0.29+0.362026-08-07 → 2026-08-30
tmax00Znearest90d23 1 QC4.63 [3.74, 5.64]4.05-2.69 [-4.82, -0.96]5.63 [4.72, 6.43]13% [0%, 25%]26%39%+0.29+0.362026-08-07 → 2026-08-30
tmax00Znearest365d23 1 QC4.63 [3.54, 5.59]4.05-2.69 [-4.87, -0.48]5.63 [4.68, 6.40]13% [0%, 27%]26%39%+0.29+0.362026-08-07 → 2026-08-30
tmax00Znearestall23 1 QC4.63 [3.66, 5.77]4.05-2.69 [-4.99, -0.61]5.63 [4.68, 6.41]13% [0%, 25%]26%39%+0.29+0.362026-08-07 → 2026-08-30
tmax12Zbilinear30d23 1 QC4.50 [3.54, 5.66]4.06-2.45 [-4.46, -0.65]5.40 [4.34, 6.58]13% [0%, 25%]26%35%+0.31+0.362026-08-07 → 2026-08-30
tmax12Zbilinear90d23 1 QC4.50 [3.56, 5.75]4.06-2.45 [-4.81, -0.78]5.40 [4.38, 6.78]13% [0%, 25%]26%35%+0.31+0.362026-08-07 → 2026-08-30
tmax12Zbilinear365d23 1 QC4.50 [3.45, 5.73]4.06-2.45 [-4.89, -0.35]5.40 [4.28, 6.71]13% [0%, 28%]26%35%+0.31+0.362026-08-07 → 2026-08-30
tmax12Zbilinearall23 1 QC4.50 [3.46, 5.88]4.06-2.45 [-5.01, -0.57]5.40 [4.27, 6.78]13% [0%, 25%]26%35%+0.31+0.362026-08-07 → 2026-08-30
tmax12Znearest30d23 1 QC4.46 [3.44, 5.68]4.01-2.42 [-4.45, -0.65]5.38 [4.27, 6.62]9% [0%, 23%]26%35%+0.32+0.362026-08-07 → 2026-08-30
tmax12Znearest90d23 1 QC4.46 [3.43, 5.82]4.01-2.42 [-4.89, -0.72]5.38 [4.30, 6.83]9% [0%, 22%]26%35%+0.32+0.362026-08-07 → 2026-08-30
tmax12Znearest365d23 1 QC4.46 [3.34, 5.80]4.01-2.42 [-4.86, -0.31]5.38 [4.16, 6.74]9% [0%, 26%]26%35%+0.32+0.362026-08-07 → 2026-08-30
tmax12Znearestall23 1 QC4.46 [3.34, 5.93]4.01-2.42 [-5.08, -0.52]5.38 [4.15, 6.82]9% [0%, 24%]26%35%+0.32+0.362026-08-07 → 2026-08-30
tmin00Zbilinear30d23 1 QC1.88 [1.29, 2.57]1.87-0.19 [-1.26, 0.72]2.33 [1.58, 3.16]26% [9%, 44%]65%83%+0.48+0.472026-08-07 → 2026-08-30
tmin00Zbilinear90d23 1 QC1.88 [1.11, 2.74]1.87-0.19 [-1.44, 0.77]2.33 [1.31, 3.29]26% [7%, 46%]65%83%+0.48+0.472026-08-07 → 2026-08-30
tmin00Zbilinear365d23 1 QC1.88 [1.05, 2.79]1.87-0.19 [-1.59, 0.94]2.33 [1.27, 3.30]26% [0%, 46%]65%83%+0.48+0.472026-08-07 → 2026-08-30
tmin00Zbilinearall23 1 QC1.88 [1.09, 2.84]1.87-0.19 [-1.70, 0.74]2.33 [1.26, 3.51]26% [5%, 47%]65%83%+0.48+0.472026-08-07 → 2026-08-30
tmin00Znearest30d23 1 QC1.84 [1.19, 2.55]1.84+0.07 [-1.01, 0.96]2.28 [1.52, 3.05]30% [17%, 46%]57%83%+0.50+0.482026-08-07 → 2026-08-30
tmin00Znearest90d23 1 QC1.84 [0.94, 2.69]1.84+0.07 [-1.16, 1.03]2.28 [1.13, 3.15]30% [15%, 48%]57%83%+0.50+0.482026-08-07 → 2026-08-30
tmin00Znearest365d23 1 QC1.84 [0.93, 2.81]1.84+0.07 [-1.31, 1.20]2.28 [1.12, 3.17]30% [14%, 47%]57%83%+0.50+0.482026-08-07 → 2026-08-30
tmin00Znearestall23 1 QC1.84 [0.94, 2.72]1.84+0.07 [-1.38, 0.99]2.28 [1.10, 3.35]30% [14%, 48%]57%83%+0.50+0.482026-08-07 → 2026-08-30
tmin12Zbilinear30d23 1 QC2.18 [1.30, 2.80]2.17-0.33 [-1.26, 0.67]2.56 [1.74, 3.07]26% [0%, 58%]52%70%+0.40+0.392026-08-07 → 2026-08-30
tmin12Zbilinear90d23 1 QC2.18 [0.99, 2.86]2.17-0.33 [-1.37, 0.74]2.56 [1.36, 3.12]26% [0%, 72%]52%70%+0.40+0.392026-08-07 → 2026-08-30
tmin12Zbilinear365d23 1 QC2.18 [1.11, 2.88]2.17-0.33 [-1.45, 0.90]2.56 [1.51, 3.15]26% [0%, 74%]52%70%+0.40+0.392026-08-07 → 2026-08-30
tmin12Zbilinearall23 1 QC2.18 [1.10, 2.88]2.17-0.33 [-1.55, 0.69]2.56 [1.51, 3.12]26% [0%, 69%]52%70%+0.40+0.392026-08-07 → 2026-08-30
tmin12Znearest30d23 1 QC2.13 [1.25, 2.74]2.12-0.03 [-0.98, 1.00]2.46 [1.60, 3.01]17% [0%, 50%]57%70%+0.42+0.402026-08-07 → 2026-08-30
tmin12Znearest90d23 1 QC2.13 [0.96, 2.80]2.12-0.03 [-1.07, 1.05]2.46 [1.27, 3.07]17% [0%, 67%]57%70%+0.42+0.402026-08-07 → 2026-08-30
tmin12Znearest365d23 1 QC2.13 [1.04, 2.83]2.12-0.03 [-1.13, 1.24]2.46 [1.37, 3.09]17% [0%, 61%]57%70%+0.42+0.402026-08-07 → 2026-08-30
tmin12Znearestall23 1 QC2.13 [1.08, 2.82]2.12-0.03 [-1.26, 0.98]2.46 [1.39, 3.09]17% [0%, 64%]57%70%+0.42+0.402026-08-07 → 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 6, 00Z bilinear tmax+20+100-10-202026-08-07: -6.16 °F2026-08-08: -6.39 °F2026-08-09: -2.63 °F2026-08-10: +0.72 °F2026-08-11: -13.12 °F2026-08-12: -2.67 °F2026-08-13: -4.65 °F2026-08-14: -4.86 °F2026-08-15: +1.22 °F2026-08-16: -3.78 °F2026-08-17: +0.09 °F2026-08-18: +1.05 °F2026-08-19: -10.27 °F2026-08-20: -3.73 °F2026-08-21: +2.18 °F2026-08-22: +7.47 °F2026-08-23: +6.73 °F2026-08-24: -6.9 °F2026-08-25: -5.14 °F2026-08-26: +1.02 °F2026-08-27: -7.55 °F2026-08-29: +2.01 °F2026-08-30: -7.32 °F2026-08-072026-08-30°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 (24 days, newest first) · download CSV
Climatological dayError °F
2026-08-30-7.32
2026-08-29+2.01
2026-08-28—
2026-08-27-7.55
2026-08-26+1.02
2026-08-25-5.14
2026-08-24-6.90
2026-08-23+6.73
2026-08-22+7.47
2026-08-21+2.18
2026-08-20-3.73
2026-08-19-10.27
2026-08-18+1.05
2026-08-17+0.09
2026-08-16-3.78
2026-08-15+1.22
2026-08-14-4.86
2026-08-13-4.65
2026-08-12-2.67
2026-08-11-13.12
2026-08-10+0.72
2026-08-09-2.63
2026-08-08-6.39
2026-08-07-6.16

Error distribution

Distribution of the signed daily error in °F for ECMWF AIFS Single at KBOS, lead day 6-20 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: 0 days-8 to -6 °F: 5 days-6 to -4 °F: 3 days-4 to -2 °F: 4 days-2 to 0 °F: 0 days0 to 2 °F: 5 days2 to 4 °F: 2 days4 to 6 °F: 0 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| 4.65 · P90 |e| 7.53 °F-200+20 °Fn = 23 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
-10.00-8.000
-8.00-6.005
-6.00-4.003
-4.00-2.004
-2.00+0.000
+0.00+2.005
+2.00+4.002
+4.00+6.000
+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
2026-08234.68 -2.72

Availability

ModelScored period DaysCoverage
ECMWF AIFS Single2026-08-07 → 2026-08-30 23
ECMWF AIFS Single2026-08-07 → 2026-08-30 23
ECMWF AIFS Single2026-08-07 → 2026-08-30 23
ECMWF AIFS Single2026-08-07 → 2026-08-30 23

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 23 +0.13 [-1.13, 1.92] no
GraphCast (IFS init) 23 +0.34 [-0.50, 1.50] no
ECMWF IFS HRES 18 -0.20 [-2.61, 1.46] no
Persistence (baseline) 23 -1.84 [-3.53, 0.22] no

Cite this page

ShortCastCheck, KBOS aifs_single lead 6, methodology v0.2, accessed 2026-08-31, https://castcheck.zifanzhang.com/station/KBOS/model/aifs_single/lead/6/

LongCastCheck (2026). Station-level verification of raw weather-model 2 m temperature forecasts: KBOS (Boston Logan), model aifs_single, lead day 6. 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/6/

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