Strong Evening Wind?

April 11, 2007

SnapshotSnapshotInteresting development offshore this afternoon.  A clearly visible tightly wound area of low pressure is located just offshore of Newport at 3pm and headed northeast.  MM5 and our WRF model take it to Spokane by 5am, passing very near the metro area.  Our model shows 6-7 millibars pressure difference between Eugene and Portland around the 8-10pm timeperiod.  This could produce southerly wind gusts to 40 mph or so.  More interesting is the peak gust to 41 mph right at 3pm observation time at Eugene.  That’s pretty strong for Eugene.  They often don’t get gusts much more than that with the good winter storms.  I have a feeling Albany-Woodburn may see gusts over 45 mph by dinnertime.
11pm Update: 
That was a fun little system.  Peak gusts in the metro area were around 40 mph.  I see peak gust at PDX was 43 mph.  The new wind speed sensor for the ASOS system there has NOT been installed yet, although Eugene’s has.  The NWS is installing more accurate windspeed sensors at our local sites over the next few months.  It basically boils down this; the ASOS units installed in the mid 1990’s recorded a longer "peak gust", which gave us lower peak windspeeds the last 12 years.  The new instruments will take us back to the "2 second peak gust" measurement.  A prime example is that no station in the Valley recorded a peak gust above 58 mph in our big December windstorm.  Yet home weather stations recorded 60-70 mph gusts or even a bit higher in spots.
Much slower weather tomorrow and then a juicier system moves in later Friday.  The long range picture (the rest of April?) is a succession of troughs and weak ridges for plenty of showers/rain.  The dry periods will be short lived…Mark