136 
FXUS66 KSEW 102219
AFDSEW

Area Forecast Discussion
National Weather Service Seattle WA
320 PM PDT Wed Oct 10 2018

.SYNOPSIS...There were a few light showers in the Cascades late 
this afternoon, but those will end early this evening. Skies will 
continue clearing across Western Washington through this evening. 
High pressure will give the region dry weather for the next week. 
Areas of night and morning fog or low clouds are likely at times. 

&&

.SHORT TERM...What a lovely day after the recent rain and dark 
overcast days. There are a few light showers heading through the 
Cascades, otherwise skies are clearing this afternoon. The air aloft 
is still a bit cool, but it will be warming gradually over the next 
several days. A weather system will pass by to the north of the area 
Thursday night and Friday--but it is not expected to have much 
effect on Western Washington. Light northerly low level flow should 
become more easterly with time and increase. This pattern is good 
for night and morning fog for the lowlands, especially the usual 
valley locations. 

.LONG TERM...Dry weather will continue into next week with the 
strong upper ridge offshore at first, but then shifting over 
Washington by the middle of next week. Low level offshore flow will 
keep the air warm and dry except for some night and morning fog in 
the usual valley locations. I wouldn't be surprised if Seattle 
warmed to the lower 70s by the middle of next week--but that isn't 
in the forecast quite yet. After the recent bout of rainy dark 
weather, the forecasts will probably have to shake off a cool bias 
and mere 60s for highs seems a bit low. That said, the record daily 
high temps do fall off pretty quickly in the middle of October... 
highs above 70 would crack a couple daily records at Sea-Tac--the 
16th and 18th for example.

&&

.AVIATION...Moderate northerly flow aloft will prevail through 
Thursday due to a high amplitude pattern, however an upper ridge 
axis will slide in from the northwest and across Western Washington 
on Thu aftn. The air mass will be stable, with drying taking place. 
However, overnight and morning fog will again be possible on Thu AM 
due to boundary layer moisture and clear skies above. Fog will be 
shallow on Thu AM, so burnoff is expected over the course of mid-
late morning.

KSEA...Clear skies and light northerly wind are expected through 
this evening. Late tonight and Thursday morning, fog re- development 
appears likely. Fog will be shallow, so burnoff is expected in the 
16z-18z time frame. During the thickest fog soon after sunrise, a 
northerly surface wind is expected, but speeds should be 5 KT or 
less. Then clear skies will prevail Thu aftn, other than high 
cirrus. Haner

&&

.MARINE...Light northerly offshore flow will prevail through
Thursday morning, becoming northerly onshore late Thursday through 
Friday. Brief small craft strength westerly is possible through the 
Strait on Fri morning. 

Stronger northerly offshore flow will develop Friday night and 
Saturday morning, with small craft strength northeasterlies possible 
from the islands out through the Strait. Light to moderate offshore 
flow will continue into early next week. Otherwise, areas of fog 
will be possible each morning through at least Saturday. Haner

&&

.SEW WATCHES/WARNINGS/ADVISORIES...
WA...None.
PZ...None.
&&

$$

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