Monthly ECMWF Run…Ridge Stays Nearby

September 8, 2014

11pm Monday…

Last night’s 00z ECMWF maps…an average of all the ensembles for the next month.  It’s upper-level height anomaly (500mb) for 4 one-week periods.

500za_week1_bg_NA

500za_week2_bg_NA

500za_week3_bg_NA

500za_week4_bg_NA

 After this week’s ridge which is centered a bit to our west, it shifts directly over the West Coast through the rest of the month and into early October.  This would imply there is no start to the rainy season in the next few weeks; but there’s no reason a passing front or trough couldn’t give us 1/2″ of rain.

The 00z GFS ensemble chart (brand new this evening!) shows a peak in heights/temps around this Sunday and again the weekend of the 21st.

tseries_850t_000-384_Portland

Easterly flow is going to be much stronger this time around later this week as strong high pressure is dropping into the Rockies.   The WRF-GFS has 30-40 kt wind barbs over the metro area from just above the surface to around 4,000′ elevation.

kpdx.th 

It’s going to get very windy on the west slopes of the Cascades on Thursday!  I also kept Thursday’s high temp at 80 degrees due to all that wind.  That’s cooler than a +15 degree 850mb temp would suggest.

Dewpoints will also plummet even lower than during the last warm spell last week.  Looks like they may even drop down into the 20s in spots west of the Cascades.

Chief Meteorologist Mark Nelsen