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

Philadelphia Intl · ECMWF AIFS Single · lead day 4

KPHL · 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
tmax00Zbilinear30d26 1 QC2.90 [2.33, 3.59]1.72-2.72 [-3.54, -2.06]3.58 [2.74, 4.52]23% [9%, 35%]35%65%+0.19+0.502026-08-05 → 2026-08-30
tmax00Zbilinear90d26 1 QC2.90 [2.39, 3.60]1.72-2.72 [-3.51, -1.96]3.58 [2.70, 4.52]23% [4%, 34%]35%65%+0.19+0.502026-08-05 → 2026-08-30
tmax00Zbilinear365d26 1 QC2.90 [2.32, 3.61]1.72-2.72 [-3.54, -1.89]3.58 [2.66, 4.54]23% [0%, 36%]35%65%+0.19+0.502026-08-05 → 2026-08-30
tmax00Zbilinearall26 1 QC2.90 [2.38, 3.63]1.72-2.72 [-3.60, -1.94]3.58 [2.68, 4.54]23% [0%, 36%]35%65%+0.19+0.502026-08-05 → 2026-08-30
tmax00Znearest30d26 1 QC2.49 [2.00, 3.16]1.74-2.10 [-2.83, -1.47]3.13 [2.34, 4.00]23% [10%, 35%]42%73%+0.30+0.502026-08-05 → 2026-08-30
tmax00Znearest90d26 1 QC2.49 [2.01, 3.16]1.74-2.10 [-2.85, -1.38]3.13 [2.29, 3.95]23% [6%, 33%]42%73%+0.30+0.502026-08-05 → 2026-08-30
tmax00Znearest365d26 1 QC2.49 [1.95, 3.16]1.74-2.10 [-2.85, -1.29]3.13 [2.27, 4.03]23% [6%, 36%]42%73%+0.30+0.502026-08-05 → 2026-08-30
tmax00Znearestall26 1 QC2.49 [1.97, 3.19]1.74-2.10 [-2.89, -1.35]3.13 [2.27, 4.02]23% [0%, 36%]42%73%+0.30+0.502026-08-05 → 2026-08-30
tmax12Zbilinear30d26 1 QC2.47 [2.01, 2.96]1.53-2.24 [-2.79, -1.73]2.98 [2.40, 3.54]27% [15%, 37%]38%65%+0.31+0.562026-08-05 → 2026-08-30
tmax12Zbilinear90d26 1 QC2.47 [1.91, 2.99]1.53-2.24 [-2.77, -1.75]2.98 [2.32, 3.54]27% [14%, 38%]38%65%+0.31+0.562026-08-05 → 2026-08-30
tmax12Zbilinear365d26 1 QC2.47 [1.88, 3.01]1.53-2.24 [-2.84, -1.68]2.98 [2.28, 3.58]27% [14%, 40%]38%65%+0.31+0.562026-08-05 → 2026-08-30
tmax12Zbilinearall26 1 QC2.47 [1.88, 3.02]1.53-2.24 [-2.85, -1.69]2.98 [2.28, 3.62]27% [12%, 39%]38%65%+0.31+0.562026-08-05 → 2026-08-30
tmax12Znearest30d26 1 QC2.12 [1.69, 2.54]1.57-1.60 [-2.10, -1.10]2.54 [2.01, 3.02]23% [10%, 36%]46%81%+0.41+0.552026-08-05 → 2026-08-30
tmax12Znearest90d26 1 QC2.12 [1.60, 2.55]1.57-1.60 [-2.10, -1.10]2.54 [1.91, 3.03]23% [9%, 38%]46%81%+0.41+0.552026-08-05 → 2026-08-30
tmax12Znearest365d26 1 QC2.12 [1.58, 2.59]1.57-1.60 [-2.19, -1.05]2.54 [1.87, 3.08]23% [9%, 39%]46%81%+0.41+0.552026-08-05 → 2026-08-30
tmax12Znearestall26 1 QC2.12 [1.56, 2.59]1.57-1.60 [-2.14, -1.07]2.54 [1.88, 3.07]23% [7%, 38%]46%81%+0.41+0.552026-08-05 → 2026-08-30
tmin00Zbilinear30d26 1 QC2.70 [1.74, 3.58]2.70+0.05 [-0.87, 1.00]3.22 [2.22, 3.95]23% [4%, 44%]38%58%+0.05+0.072026-08-05 → 2026-08-30
tmin00Zbilinear90d26 1 QC2.70 [1.64, 3.68]2.70+0.05 [-1.09, 1.22]3.22 [2.07, 4.04]23% [0%, 44%]38%58%+0.05+0.072026-08-05 → 2026-08-30
tmin00Zbilinear365d26 1 QC2.70 [1.58, 3.76]2.70+0.05 [-1.02, 1.31]3.22 [2.07, 4.10]23% [0%, 44%]38%58%+0.05+0.072026-08-05 → 2026-08-30
tmin00Zbilinearall26 1 QC2.70 [1.60, 3.70]2.70+0.05 [-1.13, 1.23]3.22 [2.03, 4.07]23% [0%, 44%]38%58%+0.05+0.072026-08-05 → 2026-08-30
tmin00Znearest30d26 1 QC2.64 [1.74, 3.52]2.69+0.59 [-0.29, 1.55]3.24 [2.19, 4.05]23% [7%, 44%]50%62%+0.07+0.082026-08-05 → 2026-08-30
tmin00Znearest90d26 1 QC2.64 [1.57, 3.60]2.69+0.59 [-0.49, 1.73]3.24 [2.01, 4.12]23% [5%, 47%]50%62%+0.07+0.082026-08-05 → 2026-08-30
tmin00Znearest365d26 1 QC2.64 [1.59, 3.68]2.69+0.59 [-0.42, 1.81]3.24 [1.99, 4.21]23% [0%, 44%]50%62%+0.07+0.082026-08-05 → 2026-08-30
tmin00Znearestall26 1 QC2.64 [1.56, 3.67]2.69+0.59 [-0.51, 1.71]3.24 [1.93, 4.12]23% [0%, 49%]50%62%+0.07+0.082026-08-05 → 2026-08-30
tmin12Zbilinear30d26 1 QC2.39 [1.68, 3.20]2.39-0.14 [-0.88, 0.63]2.85 [2.01, 3.59]27% [13%, 41%]42%65%+0.16+0.182026-08-05 → 2026-08-30
tmin12Zbilinear90d26 1 QC2.39 [1.66, 3.30]2.39-0.14 [-0.99, 0.75]2.85 [1.98, 3.66]27% [13%, 43%]42%65%+0.16+0.182026-08-05 → 2026-08-30
tmin12Zbilinear365d26 1 QC2.39 [1.64, 3.44]2.39-0.14 [-0.98, 0.84]2.85 [1.98, 3.79]27% [10%, 43%]42%65%+0.16+0.182026-08-05 → 2026-08-30
tmin12Zbilinearall26 1 QC2.39 [1.66, 3.34]2.39-0.14 [-1.08, 0.77]2.85 [1.98, 3.69]27% [11%, 42%]42%65%+0.16+0.182026-08-05 → 2026-08-30
tmin12Znearest30d26 1 QC2.37 [1.71, 3.16]2.37+0.37 [-0.34, 1.12]2.83 [1.98, 3.64]23% [9%, 36%]50%65%+0.17+0.192026-08-05 → 2026-08-30
tmin12Znearest90d26 1 QC2.37 [1.72, 3.24]2.37+0.37 [-0.45, 1.24]2.83 [1.96, 3.69]23% [9%, 37%]50%65%+0.17+0.192026-08-05 → 2026-08-30
tmin12Znearest365d26 1 QC2.37 [1.72, 3.40]2.37+0.37 [-0.41, 1.36]2.83 [1.97, 3.82]23% [6%, 38%]50%65%+0.17+0.192026-08-05 → 2026-08-30
tmin12Znearestall26 1 QC2.37 [1.74, 3.26]2.37+0.37 [-0.48, 1.26]2.83 [1.99, 3.68]23% [0%, 37%]50%65%+0.17+0.192026-08-05 → 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 KPHL, lead day 4, 00Z bilinear tmax+10+50-5-102026-08-05: -2.88 °F2026-08-06: -2.74 °F2026-08-07: -4.58 °F2026-08-08: -2.06 °F2026-08-09: -1.58 °F2026-08-10: +0.31 °F2026-08-11: -0.2 °F2026-08-12: -6.59 °F2026-08-13: -2.4 °F2026-08-14: -5.97 °F2026-08-15: -9.01 °F2026-08-16: -2.57 °F2026-08-17: +0.05 °F2026-08-18: -3.05 °F2026-08-19: -4.09 °F2026-08-20: -0.45 °F2026-08-21: -5.16 °F2026-08-22: -0.7 °F2026-08-23: -1.78 °F2026-08-24: -4.78 °F2026-08-25: -0.83 °F2026-08-26: -3.1 °F2026-08-27: -2.84 °F2026-08-28: -2.75 °F2026-08-29: +1.95 °F2026-08-30: -2.92 °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
2026-08-30-2.92
2026-08-29+1.95
2026-08-28-2.75
2026-08-27-2.84
2026-08-26-3.10
2026-08-25-0.83
2026-08-24-4.78
2026-08-23-1.78
2026-08-22-0.70
2026-08-21-5.16
2026-08-20-0.45
2026-08-19-4.09
2026-08-18-3.05
2026-08-17+0.05
2026-08-16-2.57
2026-08-15-9.01
2026-08-14-5.97
2026-08-13-2.40
2026-08-12-6.59
2026-08-11-0.20
2026-08-10+0.31
2026-08-09-1.58
2026-08-08-2.06
2026-08-07-4.58
2026-08-06-2.74
2026-08-05-2.88

Error distribution

Distribution of the signed daily error in °F for ECMWF AIFS Single at KPHL, lead day 4-10 to -9 °F: 1 day-9 to -8 °F: 0 days-8 to -7 °F: 0 days-7 to -6 °F: 1 day-6 to -5 °F: 2 days-5 to -4 °F: 3 days-4 to -3 °F: 2 days-3 to -2 °F: 8 days-2 to -1 °F: 2 days-1 to 0 °F: 4 days0 to 1 °F: 2 days1 to 2 °F: 1 day2 to 3 °F: 0 days3 to 4 °F: 0 days4 to 5 °F: 0 days5 to 6 °F: 0 days6 to 7 °F: 0 days7 to 8 °F: 0 days8 to 9 °F: 0 days9 to 10 °F: 0 daysdashed: P50 |e| 2.75 · P90 |e| 5.57 °F-100+10 °Fn = 26 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
-10.00-9.001
-9.00-8.000
-8.00-7.000
-7.00-6.001
-6.00-5.002
-5.00-4.003
-4.00-3.002
-3.00-2.008
-2.00-1.002
-1.00+0.004
+0.00+1.002
+1.00+2.001
+2.00+3.000
+3.00+4.000
+4.00+5.000
+5.00+6.000
+6.00+7.000
+7.00+8.000
+8.00+9.000
+9.00+10.000

Month by month

00Z bilinear daily maximum, newest first.

Monthn MAE °FBias °F
2026-08262.90 -2.72

Availability

ModelScored period DaysCoverage
ECMWF AIFS Single2026-08-05 → 2026-08-30 26
ECMWF AIFS Single2026-08-05 → 2026-08-30 26
ECMWF AIFS Single2026-08-05 → 2026-08-30 26
ECMWF AIFS Single2026-08-05 → 2026-08-30 26

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 26 -0.75 [-1.77, 0.82] no
GraphCast (IFS init) 25 -1.60 [-2.06, -0.97] yes
ECMWF IFS HRES 20 -0.73 [-1.43, 1.09] no
Persistence (baseline) 26 -0.68 [-1.76, 0.51] no

Cite this page

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

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