Area Forecast Discussion
Issued by NWS Portland, OR

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FXUS66 KPQR 242139
AFDPQR

Area Forecast Discussion
National Weather Service Portland OR
237 PM PDT Sun Jun 24 2018

.SYNOPSIS...After a warm day Sunday, a Pacific weather system will
move through the area tonight, bringing in cooler and cloudy
conditions, and a chance of light rain tonight and Monday morning. A
weak ridge and seasonable weather returns Tuesday, followed by
another weak trough on Wednesday. Northwest flow then sets in for
the second half of the week, with another chance of light rain
showers by Friday.
&&

.SHORT TERM...Tonight through Wednesday...Upper trough and associated
surface front over the eastern Pacific continues to move
east/southeastward toward the WA/OR coast. Surface front will move on
shore this evening, with a strong marine push/cool down after today`s
warm afternoon. Now seeing a few light showers on KLGX about 100
miles northwest of AST, which should reach the northwest Oregon
between 03-06Z and advancing inland thereafter. Will see some late
day clearing Monday as a weak ridge builds inland. Another weak
trough approaches and moves over the area Wednesday, for increasing
cloudiness and a slight chance of light rain northern coast and
Cascades late in the day. Bright

.LONG TERM...Wednesday night through Sunday. Wed night the 12z GFS
and 12z Euro show a shortwave trough moving through the area. This
will keep an onshore flow into the area. The GFS is showing an
increase PoPs, while the Euro has the majority of moisture staying
well into Washington. However, a much deeper secondary trough is
showing on the GFS, which looks to enter the area starting around
Fri morning, and looks to increase the precip chance Sat. The Euro
however is leaning towards a weak shortwave ridge pushing on shore
in response to a blocking pattern that could develop in the Pacific
during the same time period. For the weekend the GFS has a weak
ridge dominating the area, still keeping a cooler onshore flow, and
a minimal chance for precip. The Euro for the same time period has
the blocking pattern holding, still keeping cooler onshore flow, but
severely limiting the chance for precip in the area. /42
&&

.AVIATION...VFR prevailing across the area this afternoon except
for stratus clinging on the coastline. Satellite imagery shows the
low clouds are from Lincoln City southward. Network radar shows
showers extending southwest from KUIL. These showers are ahead of
a front further offshore. This decaying front will move to the
coast this evening and inland overnight. MVFR or possibly IFR
cigs should fill-in on the coast in the evening ahead of the
front. Clouds will spread inland overnight with low VFR to MVFR
cigs and patchy rain at inland TAF sites after about 09Z Mon.
Conditions improving on Monday as cigs lift and clouds begin to
dissipate in the mid to late afternoon.

KPDX AND APPROACHES...VFR conditions prevailing with through
this evening. A decaying front bringing low VFR to MVFR cigs
after 09Z Mon. After 15Z Mon should see cigs begin to lift with
VFR prevailing after 18-21Z.  /mh

&&

.MARINE...Little change to the overall pattern through the
week. High pressure will remain over the NE Pacific, with thermal
low pressure over northern California and southern Oregon. This
will bring persistent northerly winds, which will become gusty at
times. Expect gusts to 25 kt over the central Oregon waters
into the evening hours. A weak front will move through the
waters tonight and a broader trough settles over the region Mon.
This will temporarily weaken the NE Pac high and briefly turning
the winds westerly. Another weak trough is modeled to arrive
around Wed night or early Thu.

Seas remain around 3 ft through Mon then gradually climb to
around 7 to 8 ft Tue then subside again for the rest of the
week. Also seas may be close to square over the central Oregon
waters this evening for choppy conditions.

&&

.PQR WATCHES/WARNINGS/ADVISORIES...
OR...None.
WA...None.
PZ...Small Craft Advisory for winds until 9 PM PDT this evening for
     Coastal Waters from Cascade Head OR to Florence OR out 60
     NM.

&&

$$

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This discussion is for Northwest Oregon and Southwest Washington
from the Cascade crest to 60 nautical miles offshore. This area is
commonly referred to as the CWA or forecast area.


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