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

Philadelphia Intl · ECMWF AIFS Single · lead day 8

KPHL · 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
tmax00Zbilinear30d22 1 QC4.65 [3.99, 5.49]2.50-4.04 [-5.47, -2.70]5.30 [4.25, 6.56]0% [0%, 0%]14%32%-0.08+0.352026-08-09 → 2026-08-30
tmax00Zbilinear90d22 1 QC4.65 [3.91, 5.62]2.50-4.04 [-5.62, -2.46]5.30 [4.19, 6.67]0% [0%, 0%]14%32%-0.08+0.352026-08-09 → 2026-08-30
tmax00Zbilinear365d22 1 QC4.65 [3.89, 5.73]2.50-4.04 [-5.73, -2.28]5.30 [4.12, 6.79]0% [0%, 0%]14%32%-0.08+0.352026-08-09 → 2026-08-30
tmax00Zbilinearall22 1 QC4.65 [3.95, 5.67]2.50-4.04 [-5.67, -2.45]5.30 [4.22, 6.82]0% [0%, 0%]14%32%-0.08+0.352026-08-09 → 2026-08-30
tmax00Znearest30d22 1 QC4.20 [3.61, 4.95]2.54-3.47 [-4.91, -2.07]4.91 [3.96, 6.12]5% [0%, 14%]23%32%+0.03+0.342026-08-09 → 2026-08-30
tmax00Znearest90d22 1 QC4.20 [3.52, 5.04]2.54-3.47 [-5.03, -1.84]4.91 [3.92, 6.25]5% [0%, 14%]23%32%+0.03+0.342026-08-09 → 2026-08-30
tmax00Znearest365d22 1 QC4.20 [3.52, 5.15]2.54-3.47 [-5.15, -1.66]4.91 [3.84, 6.38]5% [0%, 14%]23%32%+0.03+0.342026-08-09 → 2026-08-30
tmax00Znearestall22 1 QC4.20 [3.60, 5.10]2.54-3.47 [-5.10, -1.86]4.91 [3.93, 6.41]5% [0%, 14%]23%32%+0.03+0.342026-08-09 → 2026-08-30
tmax12Zbilinear30d22 1 QC4.19 [3.25, 5.26]2.50-3.79 [-5.12, -2.51]4.87 [4.03, 5.72]14% [0%, 27%]18%36%+0.03+0.352026-08-09 → 2026-08-30
tmax12Zbilinear90d22 1 QC4.19 [3.01, 5.46]2.50-3.79 [-5.46, -2.21]4.87 [3.76, 5.83]14% [0%, 29%]18%36%+0.03+0.352026-08-09 → 2026-08-30
tmax12Zbilinear365d22 1 QC4.19 [3.02, 5.46]2.50-3.79 [-5.46, -2.06]4.87 [3.75, 5.86]14% [0%, 29%]18%36%+0.03+0.352026-08-09 → 2026-08-30
tmax12Zbilinearall22 1 QC4.19 [3.02, 5.64]2.50-3.79 [-5.64, -2.25]4.87 [3.76, 5.95]14% [0%, 29%]18%36%+0.03+0.352026-08-09 → 2026-08-30
tmax12Znearest30d22 1 QC3.84 [3.00, 4.77]2.53-3.20 [-4.56, -1.87]4.49 [3.66, 5.27]9% [0%, 23%]23%45%+0.11+0.352026-08-09 → 2026-08-30
tmax12Znearest90d22 1 QC3.84 [2.81, 4.94]2.53-3.20 [-4.93, -1.55]4.49 [3.45, 5.39]9% [0%, 24%]23%45%+0.11+0.352026-08-09 → 2026-08-30
tmax12Znearest365d22 1 QC3.84 [2.81, 4.92]2.53-3.20 [-4.92, -1.40]4.49 [3.44, 5.42]9% [0%, 29%]23%45%+0.11+0.352026-08-09 → 2026-08-30
tmax12Znearestall22 1 QC3.84 [2.79, 5.08]2.53-3.20 [-5.08, -1.62]4.49 [3.44, 5.52]9% [0%, 29%]23%45%+0.11+0.352026-08-09 → 2026-08-30
tmin00Zbilinear30d22 1 QC2.81 [1.98, 3.38]2.78-0.28 [-1.35, 0.87]3.25 [2.43, 3.73]14% [0%, 27%]36%59%+0.30+0.232026-08-09 → 2026-08-30
tmin00Zbilinear90d22 1 QC2.81 [1.72, 3.41]2.78-0.28 [-1.46, 1.17]3.25 [1.97, 3.73]14% [0%, 29%]36%59%+0.30+0.232026-08-09 → 2026-08-30
tmin00Zbilinear365d22 1 QC2.81 [1.71, 3.49]2.78-0.28 [-1.50, 1.10]3.25 [2.00, 3.79]14% [0%, 29%]36%59%+0.30+0.232026-08-09 → 2026-08-30
tmin00Zbilinearall22 1 QC2.81 [1.56, 3.47]2.78-0.28 [-1.53, 0.83]3.25 [1.88, 3.80]14% [0%, 29%]36%59%+0.30+0.232026-08-09 → 2026-08-30
tmin00Znearest30d22 1 QC2.77 [1.81, 3.45]2.77+0.24 [-0.85, 1.38]3.23 [2.30, 3.79]14% [0%, 36%]36%59%+0.32+0.232026-08-09 → 2026-08-30
tmin00Znearest90d22 1 QC2.77 [1.42, 3.46]2.77+0.24 [-1.00, 1.69]3.23 [1.82, 3.78]14% [0%, 43%]36%59%+0.32+0.232026-08-09 → 2026-08-30
tmin00Znearest365d22 1 QC2.77 [1.38, 3.53]2.77+0.24 [-1.02, 1.61]3.23 [1.77, 3.84]14% [0%, 44%]36%59%+0.32+0.232026-08-09 → 2026-08-30
tmin00Znearestall22 1 QC2.77 [1.29, 3.53]2.77+0.24 [-1.04, 1.36]3.23 [1.63, 3.86]14% [0%, 50%]36%59%+0.32+0.232026-08-09 → 2026-08-30
tmin12Zbilinear30d22 1 QC2.20 [1.65, 2.75]2.19+0.31 [-0.45, 1.16]2.56 [1.96, 2.95]18% [0%, 33%]41%77%+0.46+0.392026-08-09 → 2026-08-30
tmin12Zbilinear90d22 1 QC2.20 [1.55, 2.80]2.19+0.31 [-0.48, 1.31]2.56 [1.68, 2.98]18% [0%, 33%]41%77%+0.46+0.392026-08-09 → 2026-08-30
tmin12Zbilinear365d22 1 QC2.20 [1.54, 2.82]2.19+0.31 [-0.51, 1.33]2.56 [1.68, 2.98]18% [0%, 33%]41%77%+0.46+0.392026-08-09 → 2026-08-30
tmin12Zbilinearall22 1 QC2.20 [1.52, 2.81]2.19+0.31 [-0.59, 1.14]2.56 [1.67, 3.00]18% [0%, 35%]41%77%+0.46+0.392026-08-09 → 2026-08-30
tmin12Znearest30d22 1 QC2.26 [1.68, 2.79]2.18+0.84 [0.07, 1.71]2.65 [1.97, 3.03]23% [4%, 38%]45%77%+0.44+0.402026-08-09 → 2026-08-30
tmin12Znearest90d22 1 QC2.26 [1.51, 2.85]2.18+0.84 [0.04, 1.85]2.65 [1.59, 3.04]23% [0%, 38%]45%77%+0.44+0.402026-08-09 → 2026-08-30
tmin12Znearest365d22 1 QC2.26 [1.48, 2.85]2.18+0.84 [-0.01, 1.88]2.65 [1.54, 3.04]23% [0%, 39%]45%77%+0.44+0.402026-08-09 → 2026-08-30
tmin12Znearestall22 1 QC2.26 [1.43, 2.87]2.18+0.84 [-0.11, 1.69]2.65 [1.49, 3.05]23% [0%, 39%]45%77%+0.44+0.402026-08-09 → 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 KPHL, lead day 8, 00Z bilinear tmax+20+100-10-202026-08-09: -5.98 °F2026-08-10: -1.84 °F2026-08-11: -1.8 °F2026-08-12: -13.09 °F2026-08-13: -2.57 °F2026-08-14: -7.64 °F2026-08-15: -7.13 °F2026-08-16: -3.64 °F2026-08-17: -5.84 °F2026-08-18: -2.82 °F2026-08-19: -2.59 °F2026-08-20: +2.73 °F2026-08-21: -4.69 °F2026-08-22: +3.91 °F2026-08-23: -4.67 °F2026-08-24: -6.47 °F2026-08-25: -3.42 °F2026-08-26: -5.19 °F2026-08-27: -1.28 °F2026-08-28: -3.69 °F2026-08-29: -6 °F2026-08-30: -5.23 °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
2026-08-30-5.23
2026-08-29-6.00
2026-08-28-3.69
2026-08-27-1.28
2026-08-26-5.19
2026-08-25-3.42
2026-08-24-6.47
2026-08-23-4.67
2026-08-22+3.91
2026-08-21-4.69
2026-08-20+2.73
2026-08-19-2.59
2026-08-18-2.82
2026-08-17-5.84
2026-08-16-3.64
2026-08-15-7.13
2026-08-14-7.64
2026-08-13-2.57
2026-08-12-13.09
2026-08-11-1.80
2026-08-10-1.84
2026-08-09-5.98

Error distribution

Distribution of the signed daily error in °F for ECMWF AIFS Single at KPHL, 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: 1 day-12 to -10 °F: 0 days-10 to -8 °F: 0 days-8 to -6 °F: 3 days-6 to -4 °F: 7 days-4 to -2 °F: 6 days-2 to 0 °F: 3 days0 to 2 °F: 0 days2 to 4 °F: 2 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| 4.29 · P90 |e| 7.06 °F-200+20 °Fn = 22 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
-12.00-10.000
-10.00-8.000
-8.00-6.003
-6.00-4.007
-4.00-2.006
-2.00+0.003
+0.00+2.000
+2.00+4.002
+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
2026-08224.65 -4.04

Availability

ModelScored period DaysCoverage
ECMWF AIFS Single2026-08-09 → 2026-08-30 22
ECMWF AIFS Single2026-08-09 → 2026-08-30 22
ECMWF AIFS Single2026-08-09 → 2026-08-30 22
ECMWF AIFS Single2026-08-09 → 2026-08-30 22

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 22 -0.25 [-1.24, 1.15] no
GraphCast (IFS init) 22 -0.64 [-2.30, 0.48] no
ECMWF IFS HRES 17 +0.85 [-0.22, 1.74] no
Persistence (baseline) 22 +0.33 [-1.49, 2.75] no

Cite this page

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

LongCastCheck (2026). Station-level verification of raw weather-model 2 m temperature forecasts: KPHL (Philadelphia Intl), 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/KPHL/model/aifs_single/lead/8/

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