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

Philadelphia Intl · ECMWF AIFS Single · lead day 9

KPHL · 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
tmax00Zbilinear30d21 1 QC4.96 [3.35, 6.54]3.37-4.24 [-6.34, -2.05]5.93 [4.00, 7.53]10% [0%, 29%]10%43%-0.24-0.122026-08-10 → 2026-08-30
tmax00Zbilinear90d21 1 QC4.96 [3.11, 6.62]3.37-4.24 [-6.39, -1.83]5.93 [3.64, 7.54]10% [0%, 38%]10%43%-0.24-0.122026-08-10 → 2026-08-30
tmax00Zbilinear365d21 1 QC4.96 [3.13, 6.91]3.37-4.24 [-6.70, -1.64]5.93 [3.61, 7.79]10% [0%, 33%]10%43%-0.24-0.122026-08-10 → 2026-08-30
tmax00Zbilinearall21 1 QC4.96 [3.01, 7.02]3.37-4.24 [-6.89, -1.23]5.93 [3.36, 7.93]10% [0%, 33%]10%43%-0.24-0.122026-08-10 → 2026-08-30
tmax00Znearest30d21 1 QC4.55 [3.20, 5.89]3.36-3.55 [-5.57, -1.44]5.38 [3.70, 6.76]0% [0%, 0%]29%43%-0.14-0.112026-08-10 → 2026-08-30
tmax00Znearest90d21 1 QC4.55 [2.99, 5.97]3.36-3.55 [-5.59, -1.21]5.38 [3.37, 6.80]0% [0%, 0%]29%43%-0.14-0.112026-08-10 → 2026-08-30
tmax00Znearest365d21 1 QC4.55 [2.99, 6.20]3.36-3.55 [-5.86, -1.06]5.38 [3.36, 7.03]0% [0%, 0%]29%43%-0.14-0.112026-08-10 → 2026-08-30
tmax00Znearestall21 1 QC4.55 [2.85, 6.21]3.36-3.55 [-6.07, -0.65]5.38 [3.16, 7.11]0% [0%, 0%]29%43%-0.14-0.112026-08-10 → 2026-08-30
tmax12Zbilinear30d21 1 QC4.94 [3.64, 6.71]3.38-4.35 [-6.67, -2.55]6.10 [4.57, 7.85]19% [6%, 32%]19%33%-0.23-0.122026-08-10 → 2026-08-30
tmax12Zbilinear90d21 1 QC4.94 [3.24, 7.28]3.38-4.35 [-7.28, -2.22]6.10 [3.94, 8.24]19% [0%, 33%]19%33%-0.23-0.122026-08-10 → 2026-08-30
tmax12Zbilinear365d21 1 QC4.94 [3.28, 7.52]3.38-4.35 [-7.52, -2.18]6.10 [3.94, 8.27]19% [0%, 32%]19%33%-0.23-0.122026-08-10 → 2026-08-30
tmax12Zbilinearall21 1 QC4.94 [3.40, 7.63]3.38-4.35 [-7.63, -2.46]6.10 [4.24, 8.66]19% [0%, 33%]19%33%-0.23-0.122026-08-10 → 2026-08-30
tmax12Znearest30d21 1 QC4.52 [3.27, 6.23]3.43-3.72 [-6.11, -1.88]5.72 [4.27, 7.39]19% [6%, 32%]24%33%-0.13-0.142026-08-10 → 2026-08-30
tmax12Znearest90d21 1 QC4.52 [2.89, 6.73]3.43-3.72 [-6.73, -1.52]5.72 [3.61, 7.74]19% [0%, 33%]24%33%-0.13-0.142026-08-10 → 2026-08-30
tmax12Znearest365d21 1 QC4.52 [2.97, 6.98]3.43-3.72 [-6.98, -1.46]5.72 [3.60, 7.76]19% [0%, 32%]24%33%-0.13-0.142026-08-10 → 2026-08-30
tmax12Znearestall21 1 QC4.52 [3.01, 7.10]3.43-3.72 [-7.10, -1.77]5.72 [3.98, 8.13]19% [0%, 33%]24%33%-0.13-0.142026-08-10 → 2026-08-30
tmin00Zbilinear30d21 1 QC3.83 [2.84, 4.94]3.83-0.05 [-1.79, 1.65]4.48 [3.33, 5.52]14% [0%, 25%]29%33%+0.16-0.102026-08-10 → 2026-08-30
tmin00Zbilinear90d21 1 QC3.83 [2.69, 4.98]3.83-0.05 [-1.74, 1.82]4.48 [3.13, 5.59]14% [0%, 27%]29%33%+0.16-0.102026-08-10 → 2026-08-30
tmin00Zbilinear365d21 1 QC3.83 [2.75, 5.17]3.83-0.05 [-1.78, 1.91]4.48 [3.22, 5.68]14% [0%, 29%]29%33%+0.16-0.102026-08-10 → 2026-08-30
tmin00Zbilinearall21 1 QC3.83 [2.72, 5.21]3.83-0.05 [-1.95, 1.97]4.48 [3.18, 5.67]14% [0%, 29%]29%33%+0.16-0.102026-08-10 → 2026-08-30
tmin00Znearest30d21 1 QC3.81 [2.81, 4.94]3.80+0.46 [-1.29, 2.16]4.48 [3.18, 5.65]5% [0%, 14%]24%43%+0.17-0.092026-08-10 → 2026-08-30
tmin00Znearest90d21 1 QC3.81 [2.70, 5.00]3.80+0.46 [-1.22, 2.34]4.48 [2.97, 5.70]5% [0%, 18%]24%43%+0.17-0.092026-08-10 → 2026-08-30
tmin00Znearest365d21 1 QC3.81 [2.72, 5.20]3.80+0.46 [-1.24, 2.38]4.48 [2.98, 5.84]5% [0%, 17%]24%43%+0.17-0.092026-08-10 → 2026-08-30
tmin00Znearestall21 1 QC3.81 [2.72, 5.22]3.80+0.46 [-1.42, 2.43]4.48 [2.99, 5.83]5% [0%, 17%]24%43%+0.17-0.092026-08-10 → 2026-08-30
tmin12Zbilinear30d21 1 QC3.20 [2.22, 4.10]3.17-0.20 [-2.32, 1.73]3.95 [2.85, 4.83]19% [7%, 36%]48%52%+0.30+0.092026-08-10 → 2026-08-30
tmin12Zbilinear90d21 1 QC3.20 [2.17, 4.25]3.17-0.20 [-2.70, 1.86]3.95 [2.74, 4.92]19% [7%, 40%]48%52%+0.30+0.092026-08-10 → 2026-08-30
tmin12Zbilinear365d21 1 QC3.20 [2.10, 4.30]3.17-0.20 [-2.76, 2.00]3.95 [2.65, 4.93]19% [6%, 39%]48%52%+0.30+0.092026-08-10 → 2026-08-30
tmin12Zbilinearall21 1 QC3.20 [2.18, 4.18]3.17-0.20 [-3.09, 1.68]3.95 [2.78, 4.88]19% [0%, 39%]48%52%+0.30+0.092026-08-10 → 2026-08-30
tmin12Znearest30d21 1 QC3.14 [2.17, 4.10]3.18+0.31 [-1.88, 2.28]3.97 [2.66, 5.00]19% [6%, 33%]48%52%+0.31+0.092026-08-10 → 2026-08-30
tmin12Znearest90d21 1 QC3.14 [2.13, 4.19]3.18+0.31 [-2.29, 2.40]3.97 [2.60, 5.10]19% [0%, 33%]48%52%+0.31+0.092026-08-10 → 2026-08-30
tmin12Znearest365d21 1 QC3.14 [2.10, 4.23]3.18+0.31 [-2.33, 2.54]3.97 [2.55, 5.14]19% [0%, 33%]48%52%+0.31+0.092026-08-10 → 2026-08-30
tmin12Znearestall21 1 QC3.14 [2.10, 4.16]3.18+0.31 [-2.61, 2.21]3.97 [2.57, 4.98]19% [0%, 33%]48%52%+0.31+0.092026-08-10 → 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 KPHL, lead day 9, 00Z bilinear tmax+20+100-10-202026-08-10: +0.3 °F2026-08-11: -2.43 °F2026-08-12: -6.78 °F2026-08-13: -5.62 °F2026-08-14: -8.01 °F2026-08-15: -12.02 °F2026-08-16: -2.98 °F2026-08-17: -12.08 °F2026-08-18: -6.7 °F2026-08-19: -4.47 °F2026-08-20: +2.09 °F2026-08-21: +2.02 °F2026-08-22: -2.66 °F2026-08-23: -2.22 °F2026-08-24: +2.42 °F2026-08-25: -4.7 °F2026-08-26: -5.53 °F2026-08-27: -4.52 °F2026-08-28: -7.02 °F2026-08-29: +0.73 °F2026-08-30: -8.82 °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
2026-08-30-8.82
2026-08-29+0.73
2026-08-28-7.02
2026-08-27-4.52
2026-08-26-5.53
2026-08-25-4.70
2026-08-24+2.42
2026-08-23-2.22
2026-08-22-2.66
2026-08-21+2.02
2026-08-20+2.09
2026-08-19-4.47
2026-08-18-6.70
2026-08-17-12.08
2026-08-16-2.98
2026-08-15-12.02
2026-08-14-8.01
2026-08-13-5.62
2026-08-12-6.78
2026-08-11-2.43
2026-08-10+0.30

Error distribution

Distribution of the signed daily error in °F for ECMWF AIFS Single at KPHL, 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: 2 days-12 to -10 °F: 0 days-10 to -8 °F: 2 days-8 to -6 °F: 3 days-6 to -4 °F: 5 days-4 to -2 °F: 4 days-2 to 0 °F: 0 days0 to 2 °F: 2 days2 to 4 °F: 3 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| 4.52 · P90 |e| 8.82 °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
-14.00-12.002
-12.00-10.000
-10.00-8.002
-8.00-6.003
-6.00-4.005
-4.00-2.004
-2.00+0.000
+0.00+2.002
+2.00+4.003
+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
2026-08214.96 -4.24

Availability

ModelScored period DaysCoverage
ECMWF AIFS Single2026-08-10 → 2026-08-30 21
ECMWF AIFS Single2026-08-10 → 2026-08-30 21
ECMWF AIFS Single2026-08-10 → 2026-08-30 21
ECMWF AIFS Single2026-08-10 → 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 -0.19 [-1.95, 1.49] no
GraphCast (IFS init) 21 -0.91 [-2.34, 0.14] no
ECMWF IFS HRES 16 -0.85 [-7.92, 2.27] no
Persistence (baseline) 21 +0.96 [-1.41, 3.12] no

Cite this page

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

LongCastCheck (2026). Station-level verification of raw weather-model 2 m temperature forecasts: KPHL (Philadelphia Intl), 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/KPHL/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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