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

Newark Liberty · GraphCast (IFS init) · lead day 8

KEWR · graphcast_ifs · 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, 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
tmax00Zbilinear30d22 1 QC4.60 [3.79, 5.88]3.44-3.76 [-5.69, -2.03]5.57 [4.70, 6.74]23% [11%, 33%]23%32%-0.05+0.132026-08-09 → 2026-08-30
tmax00Zbilinear90d22 1 QC4.60 [3.80, 6.08]3.44-3.76 [-6.01, -1.98]5.57 [4.69, 7.04]23% [10%, 33%]23%32%-0.05+0.132026-08-09 → 2026-08-30
tmax00Zbilinear365d28 1 QC4.69 [3.95, 5.72]3.14-4.03 [-5.68, -2.45]5.56 [4.83, 6.57]18% [0%, 29%]21%32%+0.27+0.512026-01-09 → 2026-08-30
tmax00Zbilinearall28 1 QC4.69 [3.93, 5.72]3.14-4.03 [-5.67, -2.41]5.56 [4.79, 6.55]18% [0%, 30%]21%32%+0.27+0.512026-01-09 → 2026-08-30
tmax00Znearest30d22 1 QC4.49 [3.67, 5.62]3.57-3.25 [-5.22, -1.43]5.40 [4.50, 6.54]18% [5%, 30%]27%36%-0.03+0.102026-08-09 → 2026-08-30
tmax00Znearest90d22 1 QC4.49 [3.65, 5.91]3.57-3.25 [-5.61, -1.37]5.40 [4.48, 6.78]18% [0%, 30%]27%36%-0.03+0.102026-08-09 → 2026-08-30
tmax00Znearest365d28 1 QC4.60 [3.86, 5.60]3.24-3.63 [-5.39, -1.98]5.42 [4.65, 6.39]14% [0%, 27%]25%36%+0.28+0.502026-01-09 → 2026-08-30
tmax00Znearestall28 1 QC4.60 [3.84, 5.59]3.24-3.63 [-5.43, -1.88]5.42 [4.64, 6.38]14% [0%, 26%]25%36%+0.28+0.502026-01-09 → 2026-08-30
tmax12Zbilinear30d22 1 QC5.75 [5.08, 6.53]3.06-5.40 [-6.49, -4.43]6.62 [5.94, 7.21]9% [0%, 21%]14%23%-0.32+0.222026-08-09 → 2026-08-30
tmax12Zbilinear90d22 1 QC5.75 [5.01, 6.51]3.06-5.40 [-6.44, -4.38]6.62 [5.92, 7.25]9% [0%, 22%]14%23%-0.32+0.222026-08-09 → 2026-08-30
tmax12Zbilinear365d27 1 QC5.35 [4.27, 6.22]3.15-4.74 [-6.14, -2.84]6.21 [4.98, 6.97]11% [0%, 24%]15%22%+0.16+0.512026-01-09 → 2026-08-30
tmax12Zbilinearall27 1 QC5.35 [4.21, 6.20]3.15-4.74 [-6.05, -2.86]6.21 [4.79, 7.01]11% [0%, 24%]15%22%+0.16+0.512026-01-09 → 2026-08-30
tmax12Znearest30d22 1 QC5.59 [4.87, 6.26]3.28-5.07 [-6.12, -4.01]6.55 [5.72, 7.17]9% [0%, 20%]14%27%-0.28+0.172026-08-09 → 2026-08-30
tmax12Znearest90d22 1 QC5.59 [4.74, 6.33]3.28-5.07 [-6.16, -3.98]6.55 [5.67, 7.15]9% [0%, 22%]14%27%-0.28+0.172026-08-09 → 2026-08-30
tmax12Znearest365d27 1 QC5.30 [4.35, 6.03]3.36-4.45 [-5.83, -2.49]6.20 [5.08, 6.98]11% [0%, 23%]15%26%+0.17+0.482026-01-09 → 2026-08-30
tmax12Znearestall27 1 QC5.30 [4.38, 6.02]3.36-4.45 [-5.78, -2.66]6.20 [4.96, 6.90]11% [0%, 24%]15%26%+0.17+0.482026-01-09 → 2026-08-30
tmin00Zbilinear30d22 1 QC3.75 [2.90, 4.45]3.62+0.72 [-0.76, 2.13]4.18 [3.21, 4.84]9% [0%, 19%]18%36%+0.21+0.172026-08-09 → 2026-08-30
tmin00Zbilinear90d22 1 QC3.75 [2.77, 4.52]3.62+0.72 [-0.85, 2.44]4.18 [3.09, 4.89]9% [0%, 22%]18%36%+0.21+0.172026-08-09 → 2026-08-30
tmin00Zbilinear365d28 1 QC3.34 [2.14, 4.20]3.26+0.60 [-0.60, 1.81]3.82 [2.40, 4.64]11% [0%, 20%]25%50%+0.44+0.462026-01-09 → 2026-08-30
tmin00Zbilinearall28 1 QC3.34 [2.00, 4.19]3.26+0.60 [-0.63, 1.96]3.82 [2.16, 4.60]11% [0%, 20%]25%50%+0.44+0.462026-01-09 → 2026-08-30
tmin00Znearest30d22 1 QC3.91 [3.10, 4.57]3.93-0.20 [-1.88, 1.31]4.38 [3.62, 4.92]14% [5%, 21%]14%32%+0.17+0.102026-08-09 → 2026-08-30
tmin00Znearest90d22 1 QC3.91 [2.95, 4.62]3.93-0.20 [-1.97, 1.64]4.38 [3.35, 4.94]14% [0%, 25%]14%32%+0.17+0.102026-08-09 → 2026-08-30
tmin00Znearest365d28 1 QC3.52 [2.41, 4.34]3.55-0.35 [-1.70, 0.96]4.04 [2.78, 4.73]14% [6%, 25%]18%43%+0.41+0.412026-01-09 → 2026-08-30
tmin00Znearestall28 1 QC3.52 [2.23, 4.29]3.55-0.35 [-1.81, 1.07]4.04 [2.62, 4.74]14% [6%, 25%]18%43%+0.41+0.412026-01-09 → 2026-08-30
tmin12Zbilinear30d22 1 QC3.44 [2.76, 4.02]3.34+1.00 [-0.30, 2.34]3.94 [3.33, 4.42]9% [0%, 18%]23%41%+0.27+0.232026-08-09 → 2026-08-30
tmin12Zbilinear90d22 1 QC3.44 [2.75, 4.08]3.34+1.00 [-0.43, 2.56]3.94 [3.36, 4.46]9% [0%, 18%]23%41%+0.27+0.232026-08-09 → 2026-08-30
tmin12Zbilinear365d27 1 QC3.52 [2.94, 4.08]3.15+1.54 [0.24, 3.48]3.99 [3.46, 4.46]7% [0%, 15%]22%37%+0.41+0.472026-01-09 → 2026-08-30
tmin12Zbilinearall27 1 QC3.52 [2.88, 4.11]3.15+1.54 [0.09, 3.44]3.99 [3.40, 4.49]7% [0%, 15%]22%37%+0.41+0.472026-01-09 → 2026-08-30
tmin12Znearest30d22 1 QC3.48 [2.91, 4.01]3.47+0.16 [-1.25, 1.61]4.01 [3.40, 4.48]9% [0%, 18%]23%45%+0.26+0.212026-08-09 → 2026-08-30
tmin12Znearest90d22 1 QC3.48 [2.82, 4.04]3.47+0.16 [-1.41, 1.95]4.01 [3.34, 4.48]9% [0%, 18%]23%45%+0.26+0.212026-08-09 → 2026-08-30
tmin12Znearest365d27 1 QC3.38 [2.76, 3.95]3.26+0.67 [-0.67, 2.60]3.91 [3.31, 4.37]11% [0%, 20%]22%48%+0.43+0.452026-01-09 → 2026-08-30
tmin12Znearestall27 1 QC3.38 [2.79, 3.99]3.26+0.67 [-0.84, 2.61]3.91 [3.26, 4.41]11% [0%, 20%]22%48%+0.43+0.452026-01-09 → 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 GraphCast (IFS init) at KEWR, lead day 8, 00Z bilinear tmax+20+100-10-202026-08-09: -6.76 °F2026-08-10: -4.63 °F2026-08-11: -0.44 °F2026-08-12: -8.29 °F2026-08-13: -2.36 °F2026-08-14: -2.17 °F2026-08-15: -6.48 °F2026-08-16: -3.1 °F2026-08-17: -0.59 °F2026-08-18: -7.37 °F2026-08-19: -7.87 °F2026-08-20: +3.78 °F2026-08-21: -0.2 °F2026-08-22: +5.22 °F2026-08-23: -0.11 °F2026-08-24: -5.32 °F2026-08-25: -7.14 °F2026-08-26: -4.41 °F2026-08-27: +0.23 °F2026-08-28: -12.32 °F2026-08-29: -6.29 °F2026-08-30: -6.1 °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
2026-08-30-6.10
2026-08-29-6.29
2026-08-28-12.32
2026-08-27+0.23
2026-08-26-4.41
2026-08-25-7.14
2026-08-24-5.32
2026-08-23-0.11
2026-08-22+5.22
2026-08-21-0.20
2026-08-20+3.78
2026-08-19-7.87
2026-08-18-7.37
2026-08-17-0.59
2026-08-16-3.10
2026-08-15-6.48
2026-08-14-2.17
2026-08-13-2.36
2026-08-12-8.29
2026-08-11-0.44
2026-08-10-4.63
2026-08-09-6.76

Error distribution

Distribution of the signed daily error in °F for GraphCast (IFS init) at KEWR, 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: 2 days-8 to -6 °F: 8 days-6 to -4 °F: 5 days-4 to -2 °F: 4 days-2 to 0 °F: 5 days0 to 2 °F: 1 day2 to 4 °F: 1 day4 to 6 °F: 1 day6 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| 4.93 · P90 |e| 7.99 °F-200+20 °Fn = 28 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
-10.00-8.002
-8.00-6.008
-6.00-4.005
-4.00-2.004
-2.00+0.005
+0.00+2.001
+2.00+4.001
+4.00+6.001
+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
2026-08224.60 -3.76
2026-0165.01 -5.01

Availability

ModelScored period DaysCoverage
GraphCast (IFS init)2026-01-09 → 2026-08-30 28
GraphCast (IFS init)2026-01-09 → 2026-08-30 28
GraphCast (IFS init)2026-01-09 → 2026-08-30 27
GraphCast (IFS init)2026-01-09 → 2026-08-30 27

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 22 +0.29 [-1.08, 1.87] no
NCEP GFS 22 +1.04 [-0.04, 3.28] no
ECMWF IFS HRES 17 +1.40 [0.19, 2.79] yes
Persistence (baseline) 22 +0.23 [-1.49, 2.92] no

Cite this page

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

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