Western Washington

523 
FXUS66 KSEW 050254
AFDSEW

Area Forecast Discussion
National Weather Service Seattle WA
754 PM PDT Tue Oct 4 2022

.UPDATE...Mostly clear across the Cascades into to
central/northern interior this evening with low clouds across the
Southwest Interior and along the coast. Increasing low clouds
tonight into Wednesday morning for the area. Clouds will clear
into Wednesday afternoon with temperatures into the upper 60s and
low 70s late in the day.

&&

.SYNOPSIS...Increasing onshore flow tonight for low clouds into
Wednesday morning. Dry, warmer weather through early next week
with an upper ridge over the area. 

&&

.SHORT TERM /TONIGHT THROUGH FRIDAY/...Current satellite shows 
most of the marine stratus has retreated to west of the Olympics 
and along the coast. However, this does not mean points east are 
fully out of it as a look out the window continues to show 
lingering visibility limitations. The biggest impact remains on 
temperatures, as lowland temps range from the upper 50s to mid 60s
at the time of this writing /230 PM PDT/. Did end up issuing an 
afternoon update to the forecast taking about 5 or so degrees off 
of what was inherited, but it would appear that was not low 
enough.

Otherwise, the near term proves to be rather boring in its static 
nature. An upper level ridge will remain in place over the Western 
U.S. throughout the short term period. Temperatures will remain 
mild...although still very unseasonably warm...mainly in the lower 
to mid 70s again Wednesday before warming even further to the mid to 
upper 70s Thursday and Friday. To provide some perspective, high 
temps in the Seattle area should be down in the lower to mid 60 this 
time of year...thus should current forecast hold, the area would be 
running anywhere from 5 to 15 degrees above normal.  18

.LONG TERM /SATURDAY THROUGH TUESDAY/...Although retrograding back 
over the Pacific waters, upper level ridging will remain the 
dominant weather feature for the remainder of the forecast period. 
Continued light easterly flow Saturday and Sunday will give 
temperatures a bit of a nudge with lowland highs generally in the 
mid to upper 70s both days. Onshore flow returns Monday, bringing 
temps back into the upper 60s to lower 70s. A high degree of 
uncertainty exists for the final two days of the forecast period as 
deterministic forecasts remain divided on whether or not a frontal 
system will pass through the area, not only helping cool temps, but 
also bringing the prospect for some much needed precip. The ECMWF 
leans in this direction, but the GFS keeps conditions dry. Ensemble 
members are starting to lean in the direction of the ECMWF but look 
like they need more convincing. As such, only slight chance PoPs 
present in the forecast at this time, however it is worth noting the 
high degree of uncertainty. 18

&&

.AVIATION...South/southwesterly winds turning north/northwesterly 
this evening 3 to 5 knots. Light onshore flow will return tonight 
bringing another round of marine stratus and fog inland. IFR/LIFR 
conditions are likely, similar to this morning for interior 
terminals. Stratus and fog will most likely begin to lift and 
scatter out late in the afternoon.

KSEA...Marine stratus and fog are likely to return with another 
onshore push overnight. Cannot rule out IFR/LIFR conditions once 
again to the terminal around 06-09z, and continue into the morning 
hours. Likely will lift and scatter late into the afternoon, around 
20-22z. Watching the potential for north winds to return to the 
terminal around 14Z and increase to around 6-7 knots by 19Z. 

Mazurkiewicz/Kristell

&&

.MARINE...Surface high pressure sitting offshore will continue to
provide light onshore flow to our area. As onshore flow 
continues, Small Craft Advisory westerlies are expected for the 
Central and Eastern Strait of Juan De Fuca this evening. Stratus 
and fog are likely over the coastal waters again Wednesday 
morning, with visibilities 3SM or below.

Southerly winds over the coastal waters will back to the north 
later this week. Winds may hover right under Small Craft Advisory 
thresholds during this time, but confidence is marginal. 

Mazurkiewicz/Kristell


&&

.HYDROLOGY...The daily hydrology discussion has ended until the 
start of the next rainy season; it will only be updated as needed.

&&

.FIRE WEATHER...Dry and warm conditions will remain in place over 
the entire forecast period. While RH recoveries in the lowlands will 
be good to moderate, there are some concerns about mid-slope RH 
recoveries throughout the period. Weak easterly winds this weekend 
may hinder recoveries even further. In spite of all this, no 
critical fire weather thresholds are expected to be met throughout 
the forecast period. However, the aforementioned RH issues may allow 
for more active fire activity, even at night, for active incidents 
within the CWA.  18

&&

.SEW WATCHES/WARNINGS/ADVISORIES...
WA...None.
PZ...Small Craft Advisory until 11 PM PDT this evening for Central 
     U.S. Waters Strait Of Juan De Fuca-East Entrance U.S. 
     Waters Strait Of Juan De Fuca.

&&

$$