1. Forecast Pressure

2. ASOS Pressure Sensor: the best we have in the operational system.

5. VOS-Voluntary Observing Ship Program-generally aneroid barometer calibrated when in U.S. ports

6. Ship Pressures
Often seriously in error…but substantial calibration is possible when they cross other ships, pass a buoy, or come into port.

7. Moored Buoys

9. Drifting Buoy

11. Effects of resolution on pressure forecasts
Most apparent in terrain.

16. 12-km

17. I
MM5
WRF
Pressure initialization don’t look the same for a number of reasons

18. An example of a short-term pressure forecast error
Eta 24-h
03 March 00UT 1999
Eta 48-h
03 March 00UT 1999

19. 48-hr Forecasts Valid 00 UTC 8 February 2002
AVN
ETA
UKMO
NOGAPS

20. 24-Hr Forecasts Valid 00 UTC 8 February 2002
AVN
ETA
UKMO
NOGAPS

21. Station Locations
Tatoosh Is.
Cape Arago

22. 24 h Coastal Errors
TTI, WA
Large Errors
Cape Arago, OR

23. 48-h Errors
48h errors much larger and frequent than 24-h errors

24. GFS vs. Eta
24-h errors
NCEP GFS better than Eta on average

25. 48-h errors
Eta under forecasts

26. West Coast