Rainy August Night

August 11, 2009

The Dry Spell Is Over

The Dry Spell Is Over

Our dry spell is definitely over this evening as a good slug of rainfall is moving through the region.  Looks like this will go down as the 8th driest period in PDX’s history.  That would be 28 days without even a trace of rain.  If you allow a trace, then we’ve gone 71 days…back in 1967.

High level moisture is pulling away from the lower level wave along the front offshore.  Radar doesn’t look as impressive off to the southwest as well, so we’re probably in the heaviest rain right now, to be followed by lots of lighter rain the rest of the night.  Models have been having real trouble forecasting rain amounts.  Earlier runs showed an inch or more for the Metro area, now the WRF-GFS and our own RPM are showing .50″ or less.  That does seem a bit more reasonable considering there isn’t much more deep moisture offshore.

Not much to talk about for tomorrow through Friday.  Troughiness hangs nearby as the airmass cools off.  850 mb temps bottom out in the mid single-digits Thursday and Friday.  But not much rain.

Ridging gradually takes over during the weekend and beyond, although the last few runs of the GFS have been slower and weaker with the ridge…something to keep an eye on.

Chief Meteorologist – Mark Nelsen