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

Philadelphia Intl · NCEP GFS · lead day 7

KPHL · gfs · lead 7

Target day = initialization date + 7 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, gfs-0p25, 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 QC3.77 [2.77, 4.51]3.35-1.73 [-3.19, -0.02]4.54 [3.31, 5.24]13% [0%, 31%]30%43%+0.02+0.082026-08-08 → 2026-08-30
tmax00Zbilinear90d23 1 QC3.77 [2.41, 4.49]3.35-1.73 [-3.23, 0.28]4.54 [2.80, 5.20]13% [0%, 36%]30%43%+0.02+0.082026-08-08 → 2026-08-30
tmax00Zbilinear365d23 1 QC3.77 [2.52, 4.54]3.35-1.73 [-3.29, 0.11]4.54 [2.92, 5.23]13% [0%, 36%]30%43%+0.02+0.082026-08-08 → 2026-08-30
tmax00Zbilinearall23 1 QC3.77 [2.37, 4.59]3.35-1.73 [-3.33, 0.16]4.54 [2.69, 5.22]13% [0%, 36%]30%43%+0.02+0.082026-08-08 → 2026-08-30
tmax00Znearest30d23 1 QC3.84 [2.66, 4.77]3.57-1.92 [-3.46, -0.23]4.65 [3.25, 5.42]17% [0%, 36%]26%43%-0.00+0.022026-08-08 → 2026-08-30
tmax00Znearest90d23 1 QC3.84 [2.37, 4.80]3.57-1.92 [-3.45, -0.05]4.65 [2.66, 5.39]17% [0%, 40%]26%43%-0.00+0.022026-08-08 → 2026-08-30
tmax00Znearest365d23 1 QC3.84 [2.46, 4.84]3.57-1.92 [-3.66, -0.18]4.65 [2.81, 5.45]17% [0%, 40%]26%43%-0.00+0.022026-08-08 → 2026-08-30
tmax00Znearestall23 1 QC3.84 [2.39, 4.84]3.57-1.92 [-3.65, -0.13]4.65 [2.49, 5.48]17% [0%, 40%]26%43%-0.00+0.022026-08-08 → 2026-08-30
tmax12Zbilinear30d23 1 QC4.69 [2.93, 6.23]4.62-1.56 [-3.37, 0.81]5.95 [3.78, 7.36]17% [5%, 29%]30%39%-0.23-0.262026-08-08 → 2026-08-30
tmax12Zbilinear90d23 1 QC4.69 [2.89, 6.31]4.62-1.56 [-3.35, 1.83]5.95 [3.54, 7.45]17% [0%, 29%]30%39%-0.23-0.262026-08-08 → 2026-08-30
tmax12Zbilinear365d23 1 QC4.69 [2.74, 6.30]4.62-1.56 [-3.42, 1.41]5.95 [3.24, 7.43]17% [0%, 29%]30%39%-0.23-0.262026-08-08 → 2026-08-30
tmax12Zbilinearall23 1 QC4.69 [2.44, 6.52]4.62-1.56 [-3.57, 1.59]5.95 [2.93, 7.52]17% [0%, 29%]30%39%-0.23-0.262026-08-08 → 2026-08-30
tmax12Znearest30d23 1 QC4.50 [2.95, 5.92]4.33-1.48 [-3.21, 0.71]5.72 [3.53, 7.09]13% [5%, 22%]30%43%-0.18-0.182026-08-08 → 2026-08-30
tmax12Znearest90d23 1 QC4.50 [2.75, 5.94]4.33-1.48 [-3.18, 1.64]5.72 [3.11, 7.13]13% [0%, 21%]30%43%-0.18-0.182026-08-08 → 2026-08-30
tmax12Znearest365d23 1 QC4.50 [2.62, 5.93]4.33-1.48 [-3.17, 1.26]5.72 [2.95, 7.11]13% [0%, 22%]30%43%-0.18-0.182026-08-08 → 2026-08-30
tmax12Znearestall23 1 QC4.50 [2.45, 6.17]4.33-1.48 [-3.31, 1.41]5.72 [2.73, 7.31]13% [0%, 22%]30%43%-0.18-0.182026-08-08 → 2026-08-30
tmin00Zbilinear30d23 1 QC3.48 [2.43, 4.46]3.43+0.40 [-1.97, 2.47]4.28 [2.99, 5.17]13% [0%, 29%]35%57%+0.14+0.072026-08-08 → 2026-08-30
tmin00Zbilinear90d23 1 QC3.48 [2.31, 4.60]3.43+0.40 [-2.00, 2.60]4.28 [2.86, 5.26]13% [0%, 32%]35%57%+0.14+0.072026-08-08 → 2026-08-30
tmin00Zbilinear365d23 1 QC3.48 [2.35, 4.74]3.43+0.40 [-2.11, 2.72]4.28 [2.92, 5.42]13% [0%, 30%]35%57%+0.14+0.072026-08-08 → 2026-08-30
tmin00Zbilinearall23 1 QC3.48 [2.35, 4.58]3.43+0.40 [-2.20, 2.93]4.28 [2.90, 5.21]13% [0%, 31%]35%57%+0.14+0.072026-08-08 → 2026-08-30
tmin00Znearest30d23 1 QC3.53 [2.19, 4.67]3.49-0.35 [-2.73, 1.73]4.41 [2.82, 5.34]22% [8%, 38%]39%52%+0.13+0.062026-08-08 → 2026-08-30
tmin00Znearest90d23 1 QC3.53 [2.10, 4.71]3.49-0.35 [-2.77, 1.90]4.41 [2.69, 5.40]22% [9%, 38%]39%52%+0.13+0.062026-08-08 → 2026-08-30
tmin00Znearest365d23 1 QC3.53 [2.09, 4.98]3.49-0.35 [-2.86, 2.00]4.41 [2.71, 5.56]22% [6%, 40%]39%52%+0.13+0.062026-08-08 → 2026-08-30
tmin00Znearestall23 1 QC3.53 [2.08, 4.80]3.49-0.35 [-3.04, 2.13]4.41 [2.68, 5.48]22% [7%, 40%]39%52%+0.13+0.062026-08-08 → 2026-08-30
tmin12Zbilinear30d23 1 QC3.53 [2.61, 4.44]3.48+0.36 [-1.14, 2.27]4.23 [3.28, 5.03]17% [3%, 33%]22%52%+0.13+0.062026-08-08 → 2026-08-30
tmin12Zbilinear90d23 1 QC3.53 [2.51, 4.65]3.48+0.36 [-1.08, 2.65]4.23 [3.02, 5.17]17% [0%, 33%]22%52%+0.13+0.062026-08-08 → 2026-08-30
tmin12Zbilinear365d23 1 QC3.53 [2.54, 4.73]3.48+0.36 [-1.29, 2.55]4.23 [2.99, 5.23]17% [0%, 34%]22%52%+0.13+0.062026-08-08 → 2026-08-30
tmin12Zbilinearall23 1 QC3.53 [2.54, 4.68]3.48+0.36 [-1.23, 2.77]4.23 [3.10, 5.15]17% [0%, 33%]22%52%+0.13+0.062026-08-08 → 2026-08-30
tmin12Znearest30d23 1 QC3.38 [2.24, 4.35]3.36-0.33 [-1.72, 1.53]4.11 [2.93, 4.94]13% [0%, 28%]35%43%+0.16+0.092026-08-08 → 2026-08-30
tmin12Znearest90d23 1 QC3.38 [2.00, 4.50]3.36-0.33 [-1.69, 1.79]4.11 [2.63, 5.05]13% [0%, 31%]35%43%+0.16+0.092026-08-08 → 2026-08-30
tmin12Znearest365d23 1 QC3.38 [1.99, 4.56]3.36-0.33 [-1.90, 1.76]4.11 [2.48, 5.10]13% [0%, 30%]35%43%+0.16+0.092026-08-08 → 2026-08-30
tmin12Znearestall23 1 QC3.38 [2.07, 4.55]3.36-0.33 [-1.83, 2.04]4.11 [2.67, 5.05]13% [0%, 31%]35%43%+0.16+0.092026-08-08 → 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 NCEP GFS at KPHL, lead day 7, 00Z bilinear tmax+10+50-5-102026-08-08: +2.16 °F2026-08-09: -1.94 °F2026-08-10: +3.04 °F2026-08-11: +5.19 °F2026-08-12: -2.96 °F2026-08-13: -3.84 °F2026-08-14: -8.08 °F2026-08-15: -7.89 °F2026-08-16: +1.3 °F2026-08-17: -3.15 °F2026-08-18: -5.04 °F2026-08-19: -2.83 °F2026-08-20: -3.43 °F2026-08-21: +5.75 °F2026-08-22: -1.03 °F2026-08-23: -0.6 °F2026-08-24: -6.41 °F2026-08-25: +5.51 °F2026-08-26: -9.86 °F2026-08-27: -1.69 °F2026-08-28: +0.43 °F2026-08-29: -0.64 °F2026-08-30: -3.87 °F2026-08-082026-08-30°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 (23 days, newest first) · download CSV
Climatological dayError °F
2026-08-30-3.87
2026-08-29-0.64
2026-08-28+0.43
2026-08-27-1.69
2026-08-26-9.86
2026-08-25+5.51
2026-08-24-6.41
2026-08-23-0.60
2026-08-22-1.03
2026-08-21+5.75
2026-08-20-3.43
2026-08-19-2.83
2026-08-18-5.04
2026-08-17-3.15
2026-08-16+1.30
2026-08-15-7.89
2026-08-14-8.08
2026-08-13-3.84
2026-08-12-2.96
2026-08-11+5.19
2026-08-10+3.04
2026-08-09-1.94
2026-08-08+2.16

Error distribution

Distribution of the signed daily error in °F for NCEP GFS at KPHL, lead day 7-10 to -9 °F: 1 day-9 to -8 °F: 1 day-8 to -7 °F: 1 day-7 to -6 °F: 1 day-6 to -5 °F: 1 day-5 to -4 °F: 0 days-4 to -3 °F: 4 days-3 to -2 °F: 2 days-2 to -1 °F: 3 days-1 to 0 °F: 2 days0 to 1 °F: 1 day1 to 2 °F: 1 day2 to 3 °F: 1 day3 to 4 °F: 1 day4 to 5 °F: 0 days5 to 6 °F: 3 days6 to 7 °F: 0 days7 to 8 °F: 0 days8 to 9 °F: 0 days9 to 10 °F: 0 daysdashed: P50 |e| 3.15 · P90 |e| 7.6 °F-100+10 °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
-10.00-9.001
-9.00-8.001
-8.00-7.001
-7.00-6.001
-6.00-5.001
-5.00-4.000
-4.00-3.004
-3.00-2.002
-2.00-1.003
-1.00+0.002
+0.00+1.001
+1.00+2.001
+2.00+3.001
+3.00+4.001
+4.00+5.000
+5.00+6.003
+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
2026-08233.77 -1.73

Availability

ModelScored period DaysCoverage
NCEP GFS2026-08-08 → 2026-08-30 23
NCEP GFS2026-08-08 → 2026-08-30 23
NCEP GFS2026-08-08 → 2026-08-30 23
NCEP GFS2026-08-08 → 2026-08-30 23

Compared with other models

Paired bootstrap on the days both models cover (90d, 00Z, bilinear, daily maximum). Negative means NCEP GFS has the lower MAE. "Distinguishable" means the 95 % interval excludes zero.

Other modelCommon days MAE difference °FDistinguishable
ECMWF AIFS Single 23 +0.22 [-0.93, 0.94] no
GraphCast (IFS init) 23 -0.76 [-2.00, 0.08] no
ECMWF IFS HRES 18 +0.99 [-1.25, 1.70] no
Persistence (baseline) 23 -0.06 [-1.45, 1.17] no

Cite this page

ShortCastCheck, KPHL gfs lead 7, methodology v0.2, accessed 2026-08-31, https://castcheck.zifanzhang.com/station/KPHL/model/gfs/lead/7/

LongCastCheck (2026). Station-level verification of raw weather-model 2 m temperature forecasts: KPHL (Philadelphia Intl), model gfs, lead day 7. Methodology version 0.2, schema version 0.1, data through 2026-08-30. Accessed 2026-08-31. https://castcheck.zifanzhang.com/station/KPHL/model/gfs/lead/7/

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