391
FXUS66 KSEW 100932
AFDSEW

Area Forecast Discussion
National Weather Service Seattle WA
232 AM PDT Mon Jun 10 2024

.SYNOPSIS...A cloudy and cool morning with marine layer stratus. A
weak shortwave will move through early on Tuesday, bringing light
showers and drizzle. Mostly zonal flow aloft afterwards with near-
normal temperatures. However, cooler and wetter weather looks to
return by Friday and through the weekend.

&&

.SHORT TERM /TODAY THROUGH WEDNESDAY/...Satellite imagery and
surface observations show the marine layer moving into the
interior of western Washington. In the upper levels, a return to
zonal flow over the region with a large closed low centered over
the Gulf of Alaska. Temperatures across the region sit in the low
50s as of 2AM. A cloudy start the day today, though eventually
evaporating by the afternoon hours, giving way to mostly clear
skies by the evening except some incoming high clouds.
Temperatures should warm up fairly quickly once cloud cover
reduces and should reach the upper 60s to low 70s across the
region.

The closed low will send a shortwave trough over the region on
Tuesday, bringing with it a weak surface cold front. The
associated moisture with this system will be meager. The best
chances for shower activity early on Tuesday will be along the
Pacific coast and through the mountains, particularly through the
northern portions of the region along the border with Canada.
Most of the lowlands will not see more than a few hundredths of an
inch of rain. Areas south and east of the Seattle metro may stay
almost completely dry on Tuesday. Showers and drizzle will taper
off Tuesday afternoon, giving way to breaks of sun and clouds by
late evening. High temperatures will be cooler, reaching the mid
to upper 60s.

Mostly zonal flow will return on Wednesday, transitioning into a
weak ridge Wednesday night into Thursday. Decreasing clouds
overnight will lead to slightly cooler morning lows on Wednesday,
down to the mid to low 40s, closer to 50 in the Seattle metro.
High temperatures similar to Tuesday, in the mid to upper 60s,
perhaps up to the low 70s through the Southwest Interior.

.LONG TERM /THURSDAY THROUGH SUNDAY/...A weak and transient upper
level ridge on Thursday will keep western Washington dry and
warmer, with highs reaching the low to mid 70s. Minimum RHs look
to be the lowest on Thursday, reaching 30-40% Thursday afternoon.
The large closed-low trough over the Pacific Ocean will approach
the region by Friday, bringing with it below-normal temperatures
Friday and through the weekend as well as periodic chances for
showers across the region. Precipitation amounts continue to look
fairly light through this period with limited moisture to work
with.

LH

&&

.AVIATION...Weak ridging over western WA today for dry weather.
The low level air mass remains moist with onshore flow. Cigs over
the lowlands are mostly within IFR to MVFR range. Low clouds will
burn back toward the coast by 21z this afternoon. A frontal
system will move inland on Tuesday with showers mainly along the
coast and in the mountains. 33

KSEA...Low clouds and IFR to MVFR conditions through 19-21z. SW/W
wind 5-10kt. Winds becoming N this afternoon/evening by 00-03z.

33

&&

.MARINE...Onshore flow prevails over western WA today. A Gale
Warning remains in effect early this morning through the Strait of
Juan de Fuca. A front will cross western WA on Tuesday with
another onshore push of westerlies through the strait Tuesday
afternoon and evening. High pressure over the NE Pacific will
maintain onshore flow through the remainder of the week.

33

&&

.SEW WATCHES/WARNINGS/ADVISORIES...
WA...None.
PZ...Gale Warning until 5 AM PDT early this morning for Central U.S.
     Waters Strait Of Juan De Fuca-East Entrance U.S. Waters
     Strait Of Juan De Fuca.

&&

$$