PORTLAND, Ore. (KOIN) — Wednesday morning starts near freezing for portions of the Willamette Valley. Fog will be limited to the coldest pockets for the morning hours. Otherwise it’s a cloudy start with temperatures in the mid to upper 30s for Portland.

Clouds clear by midday Wednesday. Daytime highs reach the low 40s, then it’s partly cloudy for the afternoon.

An offshore flow gets cranking early Thursday and continues through Saturday. It will be dry, windy and cold entering the weekend.

Swipe through the graphics below for a look at this week’s weather.

The following are weather alerts issued by the National Weather Service across Oregon:

Freeze warning south central Oregon coast

* WHAT...For the Freeze Warning and Watch, sub-freezing
  temperatures as low as 30 expected. For the Air Stagnation
  Advisory, stagnant air is expected, which may lead to
  deteriorating air quality expected.

* WHERE...For the Freeze Warning, South Central Oregon Coast from
  Reedsport to Port Orford. For the Freeze Watch, the Coos County
  coast from north of Reedsport to south of Bandon. For the Air
  Stagnation Advisory, inland areas of Coos County including the
  Coquille Valley.

* WHEN...For the Freeze Warning, from 2 AM to 9 AM PST
  Wednesday. For the Air Stagnation Advisory, from 4 AM
  Wednesday to 4 AM PST Saturday. For the Freeze Watch, from
  late Wednesday night through Thursday morning.

* IMPACTS...Freeze conditions will kill crops, other sensitive
  vegetation and possibly damage unprotected outdoor plumbing. Air
  stagnation is likely to result in diminishing air quality with
  time, especially in and near areas with significant sources of
  air pollution. Diminished air quality is likely to cause health
  issues for people with respiratory problems if precautions are
  not taken.

* View the hazard area in detail at
  https://www.wrh.noaa.gov/map/?wfo=mfr

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Take steps now to protect tender plants from the cold. To prevent
freezing and possible bursting of outdoor water pipes they should
be wrapped, drained, or allowed to drip slowly. Those that have
in-ground sprinkler systems should drain them and cover above-
ground pipes to protect them from freezing.

Stagnant air southern Oregon

* WHAT...Stagnant air is expected, which may lead to
  deteriorating air quality.

* WHERE...Valleys of northern California and south central and
  southwest Oregon.

* WHEN...From 4 AM Wednesday to 4 AM PST Saturday.

* IMPACTS...Air stagnation is likely to result in diminishing
  air quality with time, especially in and near areas with
  significant sources of air pollution. Diminished air quality
  is likely to cause health issues for people with respiratory
  problems if precautions are not taken.

* ADDITIONAL DETAILS...A weak weather system is forecast to
  arrive over the weekend, which may allow for some minor mixing
  and a reduction of air stagnation conditions.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

People with respiratory illness should follow their physician`s
advice for dealing with diminished air quality. N95 masks are
effective at filtering out the majority of harmful air
particulates.

State air quality agencies highly recommend that no outdoor
burning occur and that residential wood burning devices be
limited as much as possible. According to state air quality
agencies, prolonged periods of stagnant air can hold pollutants
close to the ground where people live and breathe. Check with
your local burn agency for any current restrictions in your area.