Forecast Pressure

ASOS Pressure Sensor

12-km

An example of a short-term forecast error

Eta 24-h

03 March 00UT 1999

Eta 48-h

03 March 00UT 1999

48-hr Forecasts Valid 00 UTC 8 February 2002

AVN

UKMO

ETA

NOGAPS

24-Hr Forecasts Valid 00 UTC 8 February 2002

AVN

UKMO

ETA

NOGAPS

Station Locations

Tatoosh Is.

Cape Arago

24 h Coastal Errors

Large Errors

Inter-annual variability

TTI, WA

Cape Arago, OR

48-h Errors

48h errors much larger and frequent than 24-h errors

GFS vs. Eta 24-h errors

NCEP GFS better than Eta on average

48-h errors

GFS over forecastsEta under forecasts