Dr Jack forecast high too low

It seems that for many months Dr Jack's forecast temperature is off by -4° F consistently, sometimes I've see it too low by 7°.

Has anyone else seen this bias?

Tomorrow it is forecast 3.7° lower than the other commercial forecasts
(69.3 vs 73). I've seen this happen in the observed high temperature pretty often, not just the forecast. 4+ degrees is enough to throw off a lift and cloudbase prediction pretty far, and I've missed some good days because of this.

Has anyone else seen this?
I thought if there was widespread issues with this I could provide better feedback to Jack.

I wonder if the many updates to the RUC and NAM models have created some issues with the data or computations.


DrJack (www.drjack.info/BLIP) miniBLIPSPOT
Lat,Lon= 32.79,-84.44 (429,144)
Feb 19 - NAM
---------------------------------------
VALID.TIME 18z 21z VALID.TIME
ForecastPd 24h 27h ForecastPd
---------------------------------------
W* 430 334 W*
Sfc.Heating 217 98 Sfc.Heating
Hcrit 4153 3641 Hcrit
BL Depth 5213 5178 BL Depth
BL Top 5908 5873 BL Top
Hgt.Variab. 753 497 Hgt.Variab.
B/S Ratio 6 6 B/S Ratio
BL Wind 13 10 BL Wind
Direction 327 317 Direction
Wind Shear 19 11 Wind Shear
Max.Converg -5 1 Max.Converg
CUpot 2142 1319 CUpot
CUbase 3766 4554 CUbase
ODpot 957 953 ODpot
ODbase 4951 4920 ODbase
maxRH 88 90 maxRH
CAPE 20 20 CAPE
Temp@2m 67.2 69.3 Temp@2m