Unexpected Rain

May 23, 2007

SnapshotI think I’ve said this several times in the last couple of months…I detest spring forecasting here in the Northwest.  Temperature was just right today, but a weak system moving down the coastline spread light rain inland this evening.  As you can see to the right, amounts were not very impressive.  But Shauna’s new deck treatment was messed up and probably more than a few mowing plans were changed too.  The showers are gone now and that system should be out our area well before daybreak.  A warm night and then clouds breaking up to partly sunny should push temperatures into the mid-upper 70’s tomorrow.  No changes for Friday, but then an approaching trough will give us a strong marine push Saturday.  That plus a cooler airmass overhead Sunday gives us a  chilly, but dry day Sunday.  I should point out (as I did at 10pm), that our RPM model shows some weak convection the next 2 afternoons over the Cascades and Coast Range.  I’m assuming this is overdone…but we saw what happened today!
Long range is a tough forecast as well.  If I believe the 00z Canadian, GFS, and 12z ECMWF (all the latest runs), I should go 90-95 next Wednesday and Thursday.  A strong thermal trough, east wind, and 850mb. temps around +20.  This would be our first hot spell of the season.  However, models have been consistently too strong on ridging for the last week or so.  I’ll leave big changes to tomorrow’s forecast…Mark
Long range forecasting continues to be messy too.