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

Newark Liberty · GraphCast (IFS init) · lead day 6

KEWR · graphcast_ifs · 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, GRAP_v100, starting 2026-01-01 — 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
tmax00Zbilinear30d24 1 QC4.38 [3.42, 5.35]2.17-4.37 [-5.34, -3.41]5.10 [4.28, 5.79]17% [0%, 36%]25%33%-0.08+0.412026-08-07 → 2026-08-30
tmax00Zbilinear90d24 1 QC4.38 [3.26, 5.60]2.17-4.37 [-5.60, -3.25]5.10 [4.23, 5.95]17% [0%, 43%]25%33%-0.08+0.412026-08-07 → 2026-08-30
tmax00Zbilinear365d30 1 QC4.75 [3.68, 5.92]2.97-3.84 [-5.19, -1.82]5.46 [4.57, 6.37]13% [0%, 31%]23%30%+0.25+0.562026-01-07 → 2026-08-30
tmax00Zbilinearall30 1 QC4.75 [3.71, 5.93]2.97-3.84 [-5.24, -1.68]5.46 [4.59, 6.43]13% [0%, 30%]23%30%+0.25+0.562026-01-07 → 2026-08-30
tmax00Znearest30d24 1 QC3.96 [3.06, 4.76]2.27-3.87 [-4.74, -2.92]4.74 [3.98, 5.33]21% [4%, 40%]25%42%+0.02+0.382026-08-07 → 2026-08-30
tmax00Znearest90d24 1 QC3.96 [2.91, 4.86]2.27-3.87 [-4.85, -2.73]4.74 [3.87, 5.39]21% [0%, 47%]25%42%+0.02+0.382026-08-07 → 2026-08-30
tmax00Znearest365d30 1 QC4.44 [3.30, 5.64]3.08-3.33 [-4.66, -1.25]5.24 [4.22, 6.26]17% [0%, 36%]23%37%+0.30+0.552026-01-07 → 2026-08-30
tmax00Znearestall30 1 QC4.44 [3.40, 5.82]3.08-3.33 [-4.67, -1.11]5.24 [4.28, 6.39]17% [0%, 33%]23%37%+0.30+0.552026-01-07 → 2026-08-30
tmax12Zbilinear30d24 1 QC4.26 [3.54, 5.12]2.00-4.23 [-5.09, -3.49]4.83 [4.23, 5.65]12% [0%, 32%]21%29%-0.05+0.452026-08-07 → 2026-08-30
tmax12Zbilinear90d24 1 QC4.26 [3.42, 5.28]2.00-4.23 [-5.23, -3.35]4.83 [4.14, 5.87]12% [0%, 38%]21%29%-0.05+0.452026-08-07 → 2026-08-30
tmax12Zbilinear365d29 1 QC4.34 [3.67, 5.06]2.43-3.64 [-4.82, -1.84]4.88 [4.33, 5.58]10% [0%, 29%]17%31%+0.33+0.652026-01-07 → 2026-08-30
tmax12Zbilinearall29 1 QC4.34 [3.64, 5.10]2.43-3.64 [-4.87, -1.78]4.88 [4.28, 5.63]10% [0%, 29%]17%31%+0.33+0.652026-01-07 → 2026-08-30
tmax12Znearest30d24 1 QC3.80 [3.12, 4.50]2.05-3.69 [-4.46, -2.86]4.38 [3.84, 5.02]17% [4%, 36%]25%42%+0.06+0.442026-08-07 → 2026-08-30
tmax12Znearest90d24 1 QC3.80 [2.98, 4.65]2.05-3.69 [-4.59, -2.73]4.38 [3.80, 5.13]17% [0%, 39%]25%42%+0.06+0.442026-08-07 → 2026-08-30
tmax12Znearest365d29 1 QC3.93 [3.25, 4.60]2.48-3.06 [-4.17, -1.12]4.52 [3.96, 5.16]14% [0%, 31%]21%41%+0.39+0.642026-01-07 → 2026-08-30
tmax12Znearestall29 1 QC3.93 [3.24, 4.69]2.48-3.06 [-4.29, -1.08]4.52 [3.93, 5.21]14% [0%, 30%]21%41%+0.39+0.642026-01-07 → 2026-08-30
tmin00Zbilinear30d24 1 QC2.76 [2.29, 3.24]2.65+1.27 [0.29, 2.49]3.32 [2.76, 3.87]21% [9%, 32%]38%62%+0.20+0.192026-08-07 → 2026-08-30
tmin00Zbilinear90d24 1 QC2.76 [2.23, 3.32]2.65+1.27 [0.28, 2.72]3.32 [2.76, 3.98]21% [8%, 33%]38%62%+0.20+0.192026-08-07 → 2026-08-30
tmin00Zbilinear365d30 1 QC3.15 [2.47, 4.17]3.04+1.35 [0.34, 2.65]3.98 [2.94, 5.25]23% [11%, 35%]37%60%+0.41+0.452026-01-07 → 2026-08-30
tmin00Zbilinearall30 1 QC3.15 [2.47, 4.29]3.04+1.35 [0.28, 2.65]3.98 [2.96, 5.34]23% [11%, 35%]37%60%+0.41+0.452026-01-07 → 2026-08-30
tmin00Znearest30d24 1 QC2.88 [2.43, 3.25]2.86+0.30 [-0.74, 1.61]3.31 [2.82, 3.69]8% [0%, 20%]25%62%+0.17+0.132026-08-07 → 2026-08-30
tmin00Znearest90d24 1 QC2.88 [2.39, 3.31]2.86+0.30 [-0.78, 1.99]3.31 [2.77, 3.74]8% [0%, 21%]25%62%+0.17+0.132026-08-07 → 2026-08-30
tmin00Znearest365d30 1 QC3.28 [2.58, 4.24]3.25+0.39 [-0.63, 1.76]3.99 [2.98, 5.24]10% [0%, 20%]27%60%+0.39+0.412026-01-07 → 2026-08-30
tmin00Znearestall30 1 QC3.28 [2.57, 4.31]3.25+0.39 [-0.71, 1.70]3.99 [2.99, 5.33]10% [0%, 20%]27%60%+0.39+0.412026-01-07 → 2026-08-30
tmin12Zbilinear30d24 1 QC2.89 [2.33, 3.44]2.84+1.18 [-0.07, 2.61]3.60 [2.87, 4.20]25% [10%, 40%]42%58%+0.16+0.132026-08-07 → 2026-08-30
tmin12Zbilinear90d24 1 QC2.89 [2.31, 3.49]2.84+1.18 [-0.10, 2.83]3.60 [2.83, 4.24]25% [8%, 40%]42%58%+0.16+0.132026-08-07 → 2026-08-30
tmin12Zbilinear365d29 1 QC3.20 [2.45, 4.16]3.19+1.30 [0.07, 2.88]4.19 [3.03, 5.54]28% [12%, 43%]41%55%+0.42+0.432026-01-07 → 2026-08-30
tmin12Zbilinearall29 1 QC3.20 [2.48, 4.18]3.19+1.30 [-0.16, 3.12]4.19 [3.08, 5.55]28% [11%, 42%]41%55%+0.42+0.432026-01-07 → 2026-08-30
tmin12Znearest30d24 1 QC3.00 [2.31, 3.49]3.01+0.26 [-1.02, 1.77]3.61 [2.89, 4.09]21% [8%, 36%]33%58%+0.13+0.082026-08-07 → 2026-08-30
tmin12Znearest90d24 1 QC3.00 [2.17, 3.49]3.01+0.26 [-1.02, 1.94]3.61 [2.76, 4.06]21% [7%, 40%]33%58%+0.13+0.082026-08-07 → 2026-08-30
tmin12Znearest365d29 1 QC3.35 [2.52, 4.33]3.40+0.45 [-0.82, 2.14]4.27 [3.12, 5.60]21% [9%, 35%]34%55%+0.39+0.402026-01-07 → 2026-08-30
tmin12Znearestall29 1 QC3.35 [2.54, 4.34]3.40+0.45 [-1.07, 2.27]4.27 [3.10, 5.73]21% [7%, 33%]34%55%+0.39+0.402026-01-07 → 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 GraphCast (IFS init) at KEWR, lead day 6, 00Z bilinear tmax+10+50-5-102026-08-07: -7.03 °F2026-08-08: -5.5 °F2026-08-09: -4.9 °F2026-08-10: -4.06 °F2026-08-11: -9.26 °F2026-08-12: -4.87 °F2026-08-13: -2.59 °F2026-08-14: -7.66 °F2026-08-15: -3.59 °F2026-08-16: -0.3 °F2026-08-17: -0.44 °F2026-08-18: -5.58 °F2026-08-19: -5.59 °F2026-08-20: -1.22 °F2026-08-21: -4.77 °F2026-08-22: -1.93 °F2026-08-23: -6.48 °F2026-08-24: -5.79 °F2026-08-25: -4.93 °F2026-08-26: -5.41 °F2026-08-27: -2.67 °F2026-08-28: -9.43 °F2026-08-29: +0.07 °F2026-08-30: -0.97 °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
2026-08-30-0.97
2026-08-29+0.07
2026-08-28-9.43
2026-08-27-2.67
2026-08-26-5.41
2026-08-25-4.93
2026-08-24-5.79
2026-08-23-6.48
2026-08-22-1.93
2026-08-21-4.77
2026-08-20-1.22
2026-08-19-5.59
2026-08-18-5.58
2026-08-17-0.44
2026-08-16-0.30
2026-08-15-3.59
2026-08-14-7.66
2026-08-13-2.59
2026-08-12-4.87
2026-08-11-9.26
2026-08-10-4.06
2026-08-09-4.90
2026-08-08-5.50
2026-08-07-7.03

Error distribution

Distribution of the signed daily error in °F for GraphCast (IFS init) at KEWR, lead day 6-10 to -9 °F: 2 days-9 to -8 °F: 1 day-8 to -7 °F: 3 days-7 to -6 °F: 2 days-6 to -5 °F: 5 days-5 to -4 °F: 5 days-4 to -3 °F: 1 day-3 to -2 °F: 2 days-2 to -1 °F: 3 days-1 to 0 °F: 3 days0 to 1 °F: 1 day1 to 2 °F: 0 days2 to 3 °F: 0 days3 to 4 °F: 0 days4 to 5 °F: 0 days5 to 6 °F: 1 day6 to 7 °F: 0 days7 to 8 °F: 0 days8 to 9 °F: 1 day9 to 10 °F: 0 daysdashed: P50 |e| 5.09 · P90 |e| 8.38 °F-100+10 °Fn = 30 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
-10.00-9.002
-9.00-8.001
-8.00-7.003
-7.00-6.002
-6.00-5.005
-5.00-4.005
-4.00-3.001
-3.00-2.002
-2.00-1.003
-1.00+0.003
+0.00+1.001
+1.00+2.000
+2.00+3.000
+3.00+4.000
+4.00+5.000
+5.00+6.001
+6.00+7.000
+7.00+8.000
+8.00+9.001
+9.00+10.000

Month by month

00Z bilinear daily maximum, newest first.

Monthn MAE °FBias °F
2026-08244.38 -4.37
2026-0166.25 -1.71

Availability

ModelScored period DaysCoverage
GraphCast (IFS init)2026-01-07 → 2026-08-30 30
GraphCast (IFS init)2026-01-07 → 2026-08-30 30
GraphCast (IFS init)2026-01-07 → 2026-08-30 29
GraphCast (IFS init)2026-01-07 → 2026-08-30 29

Compared with other models

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

Other modelCommon days MAE difference °FDistinguishable
ECMWF AIFS Single 24 +1.22 [-0.04, 2.79] no
NCEP GFS 24 +1.26 [-0.00, 2.81] no
ECMWF IFS HRES 19 -0.08 [-1.67, 1.35] no
Persistence (baseline) 24 +0.34 [-0.93, 1.41] no

Cite this page

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

LongCastCheck (2026). Station-level verification of raw weather-model 2 m temperature forecasts: KEWR (Newark Liberty), model graphcast_ifs, 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/KEWR/model/graphcast_ifs/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