Area Forecast Discussion
Issued by NWS Seattle/Tacoma, WA
FXUS66 KSEW 232236
Area Forecast Discussion
National Weather Service Seattle WA
336 PM PDT FRI SEP 23 2016
.SYNOPSIS...Isolated to scattered showers will linger in the
interior and Cascades this evening. A strong ridge will bring dry
and warmer weather Saturday through Monday with the warmest
weather in September possible on Monday. A marine push will cool
things down on Tuesday. Upper level trough moving out of the Gulf
of Alaska in the middle of the week will bring a threat of more
rain to the area by late in the week.
.SHORT TERM...A weak front is dissipating as it moves inland this
afternoon. Skies are clear off the coast and we`ll see just
isolated to scattered light showers in the interior and Cascades
An upper level ridge will start to build inland on Saturday for
drier weather. Low level clouds will likely linger through the
morning hours...then skies becoming partly to mostly sunny in the
afternoon. Temps will nudge upwards with highs closer to normal -
mid to upper 60s.
The upper level ridge will continue to build over the Pac NW on
Sunday...then start to shift east and farther inland on Monday.
Both days will be dry and mild with temperatures trending above
normal...a few low 80s are possible in the interior. Models are
showing an onshore push Monday night with marine clouds spreading
inland. No major changes from the previous forecast. 33
.LONG TERM...A weak cold front will drag across Western Washington
on Tuesday for cooler conditions. Highs will drop back into the
60s. This front may bring a little rain to the coast and north
Cascades...with dry weather elsewhere. An upper level trough will
dig offshore on Thursday then shift inland Thursday night or
Friday. This system will maintain a cool and unstable air mass
with a chance of showers. 33
.AVIATION...A weakening occluded front currently over the Olympic
peninsula will continue moving E. This front will mostly dissipate
before reaching the Cascades. An upper level trof of low pres over
the area will move into ern WA this evening. Strong NW flow aloft
will dvlp over the area. Light low level onshore flow will
prevail through tonight.
Meanwhile, areas of MVFR CIGs will become widespread overnight.
Expect areas of IFR VSBYs to improve to MVFR late today or early
this evening. The mtns will be partially obscd.
KSEA...Expect generally MVFR CIGs. CIGs will probably lift to VFR
behind the front but this will be temporary. Sly winds of 8-13
knots will become light overnight.
.MARINE...A weakening occluded front over the Washington coast will continue
moving east, but will mostly dissipate before reaching the
Cascades this evening. Expect westerly flow behind the front to
become nearly flat on Saturday. A weak warm front will brush the
outer coastal waters zones Saturday night. Light northerly flow
will develop on Sunday.
PZ...Small Craft Advisories are in effect for all waters except
the west entrance to the Strait of JUan de Fuca.
Small Craft Advisory for rough bar in effect until 2 AM
Saturday for the Grays Harbor Bar.
You can see an illustrated version of this discussion at