Severe Weather Alerts

Your Weather

To update your location please enter your ZIP code, city, state, airport code or country in the field below. Weather by E-mail: Forecast storm alerts. Weather E-Mail Alert Sign Up »

Next 12 Hours

Forecast data from the National Digital Forecast Database.

5 Day Forecast

• Friday
• 
• High: 59 °
• Low: 48 °
• Rain Showers

• Saturday
• 
• High: 64 °
• Low: 50 °
• Chance of Rain

• Sunday
• 
• High: 63 °
• Low: 52 °
• Chance of Rain

• Monday
• 
• High: 64 °
• Low: 50 °
• Chance of Rain

• Tuesday
• 
• High: 68 °
• Low: 41 °
• Mostly Cloudy

Area forecast discussion 
National Weather Service Portland or 
858 PM PDT Thursday may 23 2013 


Synopsis...an unseasonably cold upper level was centered along the 
Washington coast this evening and will move inland and eastward 
tonight and Friday. The last main batch of wrap around moisture will 
move through southwest Washington and northwest Oregon tonight and 
early Friday. One more shot wave on the back or west side of the low 
will swing through our forecast area later Friday and Friday night to 
continue some showers. Some lower pressure will remain over the area 
this weekend to keep a chance of showers over the area. A couple of 
systems are expected next week for increased precipitation chances. 
&& 


Short term...the upper low that has been plaguing the Pacific 
northwest the last few days with copious precipitation was centered 
along the central Washington coast this evening. The last big slug of 
moisture wrapping around the low was moving slowly eastward through 
southwest Washington and northwest Oregon this evening associated 
with a solid looking vorticity lobe or maximum. The models show this slug of 
moisture will move east of the Cascades by sunrise on Friday. Quantitative precipitation forecast as 
it moves through will be pretty substantial again. Astoria had 1.15 
inches in the 6 hours ending at 5 PM...with another .69 inches since 
5 PM though it is starting to slow down. Thus look for half to one 
inch amounts in the mountains as this feature moves through...with a 
half inch or so in the valleys. 


The main low circulation will move east Friday as this last stronger 
vorticity lobe moves east. However...there is one more short wave that 
will swing around on the back side of the low and across the northern 
part of our forecast area late Friday and Friday night for a some 
more showers...but less quantitative precipitation forecast than the last few nights. 


There is still some cyclonic flow and energy around our area this 
weekend...with a decent short wave digging south Saturday night and 
Sunday toward southern Oregon. Some model details still are not in 
very good agreement...but the bottom line there is at least a chance 
of showers much of the weekend. 


Looks like we may have 2 more record low maximum temperatures today at 
Astoria and Hillsboro. There will likely be several record rainfall 
amounts as well. Temperatures today were a couple of degrees higher than 
those Thursday as expected...and should make upper 50s to near 60 
Friday as the air mass warms slightly...with lower to middle 60s 
possible Saturday. Tolleson 


Long term...no changes. Previous discussion follows... 
westerly flow aloft likely to be persist through the early part of 
the week. This will keep region under a persistent chance for rain as 
a series of shortwaves moves through. The westerly flow off the 
Pacific will keep temperatures moderated...likely a little below 
seasonal averages. Models tend to diverge some late in the week with 
GFS and Canadian cutting off an upper low offshore. Bottom line 
though is for a continuation chance of rain. 
&& 


Aviation...another round of light to moderate rain impacting the 
coast with a mix of VFR and MVFR cigs/vis. Rain will ease late 
tonight but MVFR conditions likely hanging around through midday Friday. 
For inland areas...mainly VFR expected tonight with areas of MVFR 
occurring mainly north of ksle as the rain moving inland. Overall 
flight conditions improving as rain decreases and turns to scattered 
showers late Friday morning. Cascades frequently obscured through 
tonight. 


Kpdx and approaches...next batch of rain swinging inland this evening 
so expect MVFR ceilings and/or visible at time through about 12z. Ceilings 
improve a bit early Friday with higher MVFR to low VFR expected. 
&& 


Marine...all buoys now reporting seas between 7 and 9 feet this 
evening. Seas will continue to subside slowly overnight and Friday and 
remain around 6 feet through the weekend. 


A weak low pressure center over the north coastal waters with winds below 
10 knots but a little stronger pressure gradient offshore and to the south 
will keep winds in that area a little higher tonight. Winds relax Friday 
morning as the low pressure dissipates and high pressure builds from the 
southwest later Friday. The next system could increase winds/seas later 
sun or Monday...but still uncertainty on the track and strength of this 
system. No changes for now...as looks to be decent potential for 20 
to 25 knots southerly winds with that front. Rockey. 
&& 


Pqr watches/warnings/advisories... 
or...none. 
Washington...none. 
Pz...Small Craft Advisory for rough Columbia River bar from 3 am 
to 8 am PDT Friday. 


&& 


$$ 


More weather information online at... 
http://weather.Gov/Portland 


This discussion is for northwest Oregon and southwest Washington from 
the Cascade crest to 60 nautical miles offshore. The area is commonly 
referred to as the forecast area.