Area Forecast Discussion
Issued by NWS Portland, OR

Home | Current Version | Previous Version | Text Only | Print | Product List | Glossary On
Versions: 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28
FXUS66 KPQR 232133

Area Forecast Discussion
National Weather Service Portland Oregon
233 PM PDT Sun Oct 23 2016

.SYNOPSIS...A complex low developing offshore this afternoon will
remain a few hundred miles offshore through Tuesday. A cold front
that will stay mostly offshore tonight may produce rain for the coast
and coast range this evening. The front will move onshore for more
widespread rain on Monday. The low will move to the north Monday
night and bring a burst of gusty south winds and large surf to the
beaches late Monday night. Another low will approach form the south
on Tuesday and likely bring a moister frontal system to the area
Tuesday night through Thursday.


.SHORT TERM...Today through Wednesday...A complex low is developing
several 100 miles off of the Oregon coast this afternoon.  The
surface low associated with a weak cold front just offshore today is
entraining back around the broad Pacific low allowing the front to
stall offshore. A shortwave trough and surge of moisture wrapping
around the broad low is now moving along this front. Radar is
detecting rain off of the south Oregon coast that is moving north
towards Newport, Oregon. This rain will move north just offshore the
Oregon and south Washington coast late this afternoon through this
evening with a chance of rain for the immediate coast and coast
range. Lift and moisture associated with the wave may also generate
isolated showers for the Cascades, but the rest of the Portland
forecast area will remain mostly dry tonight.

The next front can be seen forming on satellite imagery, and may
merge with the tail end of the current front before moving onshore
Monday morning. The models are consistent that the bulk of the
moisture with this front will move into south Oregon and north
California, but light rain will still make it to the Portland
forecast area. The coast should see rain mid Monday morning with
inland areas Monday afternoon. The Central Oregon coast and coast
range will have the highest rainfall totals with 0.25 to 0.50 inch
possible Monday morning through Monday afternoon. The Cascades may
also see similar amounts with snow levels around 7000 feet.

There will be a burst of gusty south winds along the beaches and
headlands Monday night with wind gusts flirting with warning
criteria. High surf also remains a potential beach hazard Monday

The low will move north Monday night and Tuesday pulling the showers
back offshore. Most inland areas will be on the dry side Monday night
through Tuesday. Another closed low will approach from the south
Tuesday and bring a moister warm front to the region Tuesday night
and Wednesday. TJ

.LONG TERM...Wednesday night through Sunday...A complex weather
pattern continues offshore late in the week into next weekend. The
low that will bring rain to the area Wednesday moves north Wednesday
night and brings a cold front across the region on Thursday. The low
then moves inland as an open trough Thursday night as two other
Pacific lows move into the offshore waters. One low approaches from
the south, and another larger low approaches from the northwest. This
will result in dry weather for the Portland forecast area Thursday
night. The northern low deepens over the ne Pacific Friday allowing
an upper ridge to amplify over the Pacific NW, and keeping the
southern low south of northwest Oregon. The southern low moves inland
across north California and east Oregon Friday or Saturday for
showers over the Portland forecast area. The second low then moves
onshore on Sunday for a continued threat of rain. Snow levels will
remain well above the Cascade passes. TJ


.AVIATION...Rather benign tonight...with light southerly flow
aloft and light east to southeasterly flow in lower levels. Will
see generally VFR tonight with variable mid/high clouds. May see
some patchy fog in inland valleys but not much. Front approaching
region Mon am, with clouds lowering to low VFR. Likely to see
areas of MVFR along the coast with light rain after 12z. This rain
will spread inland through Mon am...but conditions look to remain
VFR over much of the interior on Mon.

KPDX AND APPROACHES...Rather benign, with VFR clouds. Easterly
winds 8 to 15 kt through early Mon am. Will see clouds lower back
under 5K ft after 16z Mon./Rockey.


.MARINE...Not much in way of change to the current forecasts and
warnings. Generally south to southeast winds 15 kt or less into
this evening, with seas 7 to 8 ft.

An occluded front will pushes across the region later tonight into
Mon am. Southerly winds will increase over the central waters
later this evening, with 20 to 25 kt winds and gusts 30 to 35 kt.
These winds will gradually spread northward tonight as the front
pushes closer to the coast. Current gale warning looks on track so
no changes. Seas will climb back to 12 to 15 ft range, with higher
seas over the outer waters.

Now, will see rather active storm pattern over the NE Pac this
week, with several very strong storms arriving. But the low
centers will remain well offshore, mostly tracking north along
130W. This will maintain decent gradients over the coastal waters,
with gales continuing on Mon, and likely through Wed at times.
Models continue to suggest increasing potential for storm force
wind gusts, especially over the outer waters for Mon night. Have
issued a storm watch for the outer waters for Mon night, with
gusts 50 to 55 kt possible at that time. Still think that closer
to shore waters will see less wind, with gusts 40 to 45 kt. So
will maintain gale warning in the inner coastal waters.

Seas will be on the increase with all the increased winds. Decent
fetch area to generate significant waves by later Mon and Tue. At
this time, with strong potential of seas above 20 ft later Mon
night, with peak seas briefly 25 to 30 ft late Mon night. Seas and
winds subside on Tue.

Active weather continues for later Tue through Fri, but winds and
seas look to be less intense.       Rockey.


PZ...Gale Warning tonight through early Mon evening on all outer
       coastal waters...or from 10 to 60 nm offshore.

     Storm Watch for Monday night on all outer coastal waters.

     Small Craft Advisory for winds tonight through Monday morning
       on all inner waters...or from shore out 10 nm.

     Gale Warning from Monday afternoon through Tue morning on all
       inner waters...or from shore out 10 nm.


Interact with us via social media:

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. is the U.S. government's official web portal to all federal, state and local government web resources and services.