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

Newark Liberty · GraphCast (IFS init) · lead day 9

KEWR · graphcast_ifs · lead 9

Target day = initialization date + 9 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
tmax00Zbilinear30d21 1 QC5.47 [4.45, 6.43]4.03-3.35 [-6.04, -0.54]5.95 [4.98, 6.77]0% [0%, 0%]14%14%-0.34-0.192026-08-10 → 2026-08-30
tmax00Zbilinear90d21 1 QC5.47 [4.29, 6.48]4.03-3.35 [-6.22, -0.34]5.95 [4.83, 6.79]0% [0%, 0%]14%14%-0.34-0.192026-08-10 → 2026-08-30
tmax00Zbilinear365d27 1 QC6.14 [4.83, 7.96]4.20-4.33 [-7.35, -1.33]6.82 [5.38, 8.65]0% [0%, 0%]11%15%-0.02+0.322026-01-10 → 2026-08-30
tmax00Zbilinearall27 1 QC6.14 [4.70, 7.98]4.20-4.33 [-7.62, -1.29]6.82 [5.30, 8.74]0% [0%, 0%]11%15%-0.02+0.322026-01-10 → 2026-08-30
tmax00Znearest30d21 1 QC5.42 [4.25, 6.37]4.30-2.84 [-5.73, 0.18]5.93 [4.81, 6.71]0% [0%, 0%]10%19%-0.32-0.272026-08-10 → 2026-08-30
tmax00Znearest90d21 1 QC5.42 [4.00, 6.49]4.30-2.84 [-5.93, 0.39]5.93 [4.62, 6.77]0% [0%, 0%]10%19%-0.32-0.272026-08-10 → 2026-08-30
tmax00Znearest365d27 1 QC6.24 [4.89, 8.23]4.59-3.98 [-7.37, -0.67]6.98 [5.42, 9.01]0% [0%, 0%]7%15%-0.03+0.262026-01-10 → 2026-08-30
tmax00Znearestall27 1 QC6.24 [4.77, 8.35]4.59-3.98 [-7.66, -0.70]6.98 [5.40, 9.19]0% [0%, 0%]7%15%-0.03+0.262026-01-10 → 2026-08-30
tmax12Zbilinear30d21 1 QC5.65 [4.56, 6.97]3.39-5.27 [-6.88, -3.96]6.68 [5.67, 7.78]14% [4%, 25%]14%19%-0.38-0.002026-08-10 → 2026-08-30
tmax12Zbilinear90d21 1 QC5.65 [4.24, 7.21]3.39-5.27 [-7.11, -3.75]6.68 [5.28, 7.99]14% [0%, 27%]14%19%-0.38-0.002026-08-10 → 2026-08-30
tmax12Zbilinear365d26 1 QC5.83 [4.61, 7.32]3.80-5.20 [-6.83, -3.44]6.97 [5.70, 8.37]12% [0%, 21%]15%19%+0.05+0.392026-01-10 → 2026-08-30
tmax12Zbilinearall26 1 QC5.83 [4.62, 7.32]3.80-5.20 [-6.97, -3.70]6.97 [5.83, 8.44]12% [0%, 21%]15%19%+0.05+0.392026-01-10 → 2026-08-30
tmax12Znearest30d21 1 QC5.48 [4.36, 6.76]3.59-4.78 [-6.45, -3.38]6.47 [5.43, 7.53]5% [0%, 12%]14%24%-0.34-0.062026-08-10 → 2026-08-30
tmax12Znearest90d21 1 QC5.48 [3.98, 6.96]3.59-4.78 [-6.68, -3.11]6.47 [5.01, 7.72]5% [0%, 13%]14%24%-0.34-0.062026-08-10 → 2026-08-30
tmax12Znearest365d26 1 QC5.76 [4.48, 7.28]4.04-4.82 [-6.57, -3.01]6.89 [5.52, 8.41]8% [0%, 18%]15%23%+0.06+0.362026-01-10 → 2026-08-30
tmax12Znearestall26 1 QC5.76 [4.56, 7.32]4.04-4.82 [-6.71, -3.25]6.89 [5.70, 8.52]8% [0%, 19%]15%23%+0.06+0.362026-01-10 → 2026-08-30
tmin00Zbilinear30d21 1 QC3.48 [2.41, 4.59]3.55+0.84 [-1.10, 2.88]4.40 [2.89, 5.48]24% [10%, 36%]29%57%+0.11-0.092026-08-10 → 2026-08-30
tmin00Zbilinear90d21 1 QC3.48 [2.31, 4.76]3.55+0.84 [-1.07, 3.20]4.40 [2.69, 5.61]24% [7%, 36%]29%57%+0.11-0.092026-08-10 → 2026-08-30
tmin00Zbilinear365d27 1 QC3.19 [2.11, 4.27]3.24+0.17 [-1.73, 2.20]4.16 [2.77, 5.18]30% [14%, 47%]37%63%+0.42+0.422026-01-10 → 2026-08-30
tmin00Zbilinearall27 1 QC3.19 [2.03, 4.29]3.24+0.17 [-1.97, 2.26]4.16 [2.70, 5.28]30% [13%, 50%]37%63%+0.42+0.422026-01-10 → 2026-08-30
tmin00Znearest30d21 1 QC3.83 [2.94, 4.73]3.82-0.05 [-2.11, 2.09]4.65 [3.26, 5.51]10% [0%, 25%]29%48%+0.02-0.182026-08-10 → 2026-08-30
tmin00Znearest90d21 1 QC3.83 [2.91, 4.90]3.82-0.05 [-2.05, 2.47]4.65 [3.18, 5.65]10% [0%, 29%]29%48%+0.02-0.182026-08-10 → 2026-08-30
tmin00Znearest365d27 1 QC3.70 [2.87, 4.54]3.51-0.76 [-2.82, 1.35]4.55 [3.35, 5.36]11% [0%, 24%]33%48%+0.33+0.372026-01-10 → 2026-08-30
tmin00Znearestall27 1 QC3.70 [2.84, 4.62]3.51-0.76 [-3.09, 1.42]4.55 [3.21, 5.42]11% [0%, 25%]33%48%+0.33+0.372026-01-10 → 2026-08-30
tmin12Zbilinear30d21 1 QC3.51 [2.83, 4.29]3.50-0.22 [-2.28, 1.97]4.14 [3.32, 4.94]19% [5%, 29%]24%48%+0.10-0.082026-08-10 → 2026-08-30
tmin12Zbilinear90d21 1 QC3.51 [2.82, 4.30]3.50-0.22 [-2.86, 2.49]4.14 [3.30, 4.91]19% [0%, 29%]24%48%+0.10-0.082026-08-10 → 2026-08-30
tmin12Zbilinear365d26 1 QC3.46 [2.79, 4.21]3.45-0.03 [-2.05, 2.16]4.10 [3.23, 4.88]15% [0%, 26%]27%54%+0.37+0.392026-01-10 → 2026-08-30
tmin12Zbilinearall26 1 QC3.46 [2.73, 4.24]3.45-0.03 [-2.15, 1.92]4.10 [3.19, 4.88]15% [0%, 27%]27%54%+0.37+0.392026-01-10 → 2026-08-30
tmin12Znearest30d21 1 QC3.83 [3.22, 4.50]3.63-1.11 [-3.32, 1.16]4.44 [3.74, 5.04]14% [5%, 23%]29%38%+0.02-0.122026-08-10 → 2026-08-30
tmin12Znearest90d21 1 QC3.83 [3.20, 4.53]3.63-1.11 [-3.85, 1.74]4.44 [3.72, 5.08]14% [0%, 24%]29%38%+0.02-0.122026-08-10 → 2026-08-30
tmin12Znearest365d26 1 QC3.83 [3.22, 4.46]3.64-0.93 [-3.08, 1.35]4.44 [3.70, 5.05]12% [0%, 20%]27%38%+0.30+0.362026-01-10 → 2026-08-30
tmin12Znearestall26 1 QC3.83 [3.23, 4.48]3.64-0.93 [-3.15, 1.15]4.44 [3.72, 5.06]12% [0%, 20%]27%38%+0.30+0.362026-01-10 → 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 9, 00Z bilinear tmax+10+50-5-102026-08-10: -3.1 °F2026-08-11: -4.51 °F2026-08-12: -1.93 °F2026-08-13: -9.65 °F2026-08-14: -6.2 °F2026-08-15: -6.56 °F2026-08-16: -5.16 °F2026-08-17: -9.51 °F2026-08-18: -6.55 °F2026-08-19: -7.4 °F2026-08-20: +3.7 °F2026-08-21: +6.17 °F2026-08-22: +8.04 °F2026-08-23: -1.63 °F2026-08-24: +1.17 °F2026-08-25: -4.75 °F2026-08-26: -6.24 °F2026-08-27: +3.18 °F2026-08-28: -7.88 °F2026-08-29: -5.05 °F2026-08-30: -6.42 °F2026-08-102026-08-30°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 (21 days, newest first) · download CSV
Climatological dayError °F
2026-08-30-6.42
2026-08-29-5.05
2026-08-28-7.88
2026-08-27+3.18
2026-08-26-6.24
2026-08-25-4.75
2026-08-24+1.17
2026-08-23-1.63
2026-08-22+8.04
2026-08-21+6.17
2026-08-20+3.70
2026-08-19-7.40
2026-08-18-6.55
2026-08-17-9.51
2026-08-16-5.16
2026-08-15-6.56
2026-08-14-6.20
2026-08-13-9.65
2026-08-12-1.93
2026-08-11-4.51
2026-08-10-3.10

Error distribution

Distribution of the signed daily error in °F for GraphCast (IFS init) at KEWR, lead day 9-20 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: 1 day-10 to -8 °F: 3 days-8 to -6 °F: 9 days-6 to -4 °F: 4 days-4 to -2 °F: 1 day-2 to 0 °F: 2 days0 to 2 °F: 1 day2 to 4 °F: 3 days4 to 6 °F: 0 days6 to 8 °F: 1 day8 to 10 °F: 1 day10 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| 6.24 · P90 |e| 9.7 °F-200+20 °Fn = 27 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
-12.00-10.001
-10.00-8.003
-8.00-6.009
-6.00-4.004
-4.00-2.001
-2.00+0.002
+0.00+2.001
+2.00+4.003
+4.00+6.000
+6.00+8.001
+8.00+10.001
+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
2026-08215.47 -3.35
2026-0168.48 -7.78

Availability

ModelScored period DaysCoverage
GraphCast (IFS init)2026-01-10 → 2026-08-30 27
GraphCast (IFS init)2026-01-10 → 2026-08-30 27
GraphCast (IFS init)2026-01-10 → 2026-08-30 26
GraphCast (IFS init)2026-01-10 → 2026-08-30 26

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 21 -0.04 [-1.20, 1.24] no
NCEP GFS 21 +0.56 [-1.09, 2.27] no
ECMWF IFS HRES 16 +0.92 [-4.95, 3.31] no
Persistence (baseline) 21 +1.37 [0.45, 2.95] yes

Cite this page

ShortCastCheck, KEWR graphcast_ifs lead 9, methodology v0.2, accessed 2026-08-31, https://castcheck.zifanzhang.com/station/KEWR/model/graphcast_ifs/lead/9/

LongCastCheck (2026). Station-level verification of raw weather-model 2 m temperature forecasts: KEWR (Newark Liberty), model graphcast_ifs, lead day 9. 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/9/

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