Rain Moving In This Evening; Stormy Sunday Afternoon

September 20, 2013

Friday 5pm…

Right on schedule, rain is arriving in the western valleys of Oregon and Washington this evening.  It’s not real impressive, but a nice line of moderate rain running right up I-5 right now.  No thunder so far and at best we’ll just see an embedded flash of lightning or rumble.

Some good news for the weekend, models have backed off on the showers a bit for tomorrow.  It probably won’t be a dry day, but showers might take a while (after noon) to get going and may not be too heavy even then.  So there IS a chance for some dry weather tomorrow.

No change for Sunday

Quite a stormy day for late September, especially at the Coast.  A strong cold front moves inland during the afternoon.  Plenty of moderate to heavy rain for at least 3-5 hours means a very wet afternoon west of the Cascades (and in the Cascades too I suppose).  Gradients and models suggest wind gusts to 60+ mph out at the Coast  midday and early afternoon.  Here in the valley strongest wind should be south of the Portland metro area and westside…30-35 mph is possible in the afternoon.

Beyond Sunday, mainly cool/cold showers Monday through Wednesday as a chilly October-like upper level trough sits overhead.  Snow level should fall to around 5,000′, maybe even a bit lower both Tuesday and Wednesday mornings.  Check out the ECMWF ensemble chart…note how far below normal temps are from Monday through Thursday.  Also note hints of more seasonal (warmer) weather returning in the last day or two of the month.

tseries_850t_000-360_Portland

Chief Meteorologist Mark Nelsen