Windy & Hot Ahead

August 31, 2006

We are going through another dramatic swing from cool & moist onshore flow to hot & dry offshore flow this evening.  East wind has already made it to Troutdale this evening.  Dewpoint at PDX is 49 at 8pm, but 37 at TTD.
North Bend-Spokane gradient which was +5 mb. yesterday evening is now -8 mb (easterly) and increasing rapidly at 8pm.  A pretty deep thermal trough for early September will be in place along the Coast or Coast Range by morning.  KPTV’s RPM-WRF model shows the current 2.3mb easterly gradient through the  Gorge (PDX-DLS) will increase to possibly 6-7 millibars by midday Friday.  That’s unusually strong for the first day of September, more like a late October east wind event.  Wind gusts to 35 mph should spread across the entire metro area by midday, not just near the Gorge.  At the west end of the Gorge, expect gusts of 45-50 mph!  The Coast forecast is tough, I think east wind will make it to the coast at least until midday, so 80 or so is possible, especially north of Newport.  Inland forecast is easy…Hot.  If the east wind is too strong, which is possible, it may be tough to hit 90 at PDX.
Saturday should be a scorcher since the wind ends, which leaves us with a hot/dry atmosphere in place, but no onshore flow either as the thermal trough sits right over us.  So I bumped the high temperature back up to 94 and didn’t lower Sunday as much.
Ridging stays nearby through much of next week, so summer continues…Mark