Active Afternoon, Slower Weekend

March 17, 2006

Pretty busy afternoon with heavy showers popping up through the cold air above.  A few little "anvil-tops" moving through give us brief bursts of heavy rain and hail.  Only 1 lightning strike near the metro area so far this afternoon (as of 4:15pm), just west of Yacolt around 1:30pm.  As mentioned below though, we often see this sort of activity peak out around sunset or just before.  This is also the pattern where we tend to see heaviest showers east side of town.  Part of that is due to the airstream "feeling" the lifting of the Cascade foothills before it actually gets there.  So Battleground, Camas, Troutdale, Gresham, Sandy, Estacada areas often get dumped on by late afternoon in this setup.

With the loss of daytime heating, showers quickly collapse after sunset…there’s no good dynamics to keep them going after that time.   One more weak disturbance drops south through Western Washington Saturday afternoon, which will probably set off a few showers over the mountains, but most likely we are done with rain for a few days (finally!).

Looks like a new trough developing way out in the Gulf of Alaska will split with most energy curling south into California Monday.  We haven’t seen much of this pattern in the last few months.  Remember this was almost constant last winter (2004-2005), leading to very little rain here.

Another trough moves much closer to us midweek, which brings rain back into the forecast.

Even though we warm up a bit the next few days, I still don’t see anything that could get our temperature up to 65 or warmer.  Do you realize we haven’t even seen 60 yet in Portland this late winter/early Spring?  Strange.  I’m going to check out the record books and see if our first 60 degree temp has been this late in recent years.   Enjoy the weekend…Mark