127
FXUS66 KSEW 132045
AFDSEW
Area Forecast Discussion
National Weather Service Seattle WA
145 PM PDT Mon May 13 2024
.SYNOPSIS...Building high pressure will allow for temperatures to
rebound upward Tuesday and Wednesday. Weak systems will bring
temperatures back down by Friday into the weekend and may bring
with them chances for precipitation across the region.
&&
.SHORT TERM /TONIGHT THROUGH THURSDAY/...As of 145pm this
afternoon temperatures we still in the upper 50s to low 60s across
western Washington, a marked change from yesterday. Onshore flow
will continue to persist today with clouds perhaps thinning out a
little more before the end of the day. The exception will be
across the central Puget Sound where a very weak convergence
boundary is still forecast to develop this afternoon through this
evening. The sensible weather with this feature may be nothing
more than a wind shift and enhanced clouds, but there is still a
slight (10-20%) chance of precipitation.
Upper level ridging will nose into the region Tuesday and build
through Wednesday allowing for temperatures to rebound up both
days. Slight cooling is expected Thursday as a wave flattens the
ridge. HeatRisk levels will remain in the green and yellow
categories through the period.
.LONG TERM /FRIDAY THROUGH MONDAY/...Forecast confidence wanes
somewhat Friday through the weekend as ensemble guidance continues
to struggle with the synoptic flow. The general consensus is for
additional waves to move through the area keeping temperatures
mild and precipitation chances in the forecast. That said, even at
the extremes of the ensemble envelope there doesn't currently
appear to be a signal for any significant weather hazards during
the extended period. -Wolcott-
&&
.AVIATION...An upper-level trough will is still on track to pass
over the region this afternoon. Westerly flow aloft will turn
northwesterly going into the evening. Ceilings remain MVFR for a
majority of terminals (except KBLI and vicinity with higher CIGs). A
couple areas are seeing improvements into VFR, but with ceilings
still hovering around 3,500 ft (topping out around 4,500 ft going
into tonight). There appears to be widespread MVFR ceilings behind
the trough going into the first part of Tuesday, before clearing out
the remainder of the day.
Additionally, hi-res guidance still shows possible
convergence zone showers developing mid afternoon over
Kitsap/Snohomish Counties and traveling southeastward into
King/Pierce Counties. Will keep the mention of vicinity showers and
variable winds in the affected terminals. Southwest winds at 5 to 10
kt inland will switch to the northwest late this afternoon/evening.
Expect 8 to 12 kt winds with gusts to 20 kt at terminals close to
the Strait of Juan de Fuca/coast.
KSEA...Still watching the potential for a convergence zone with
light/vicinity showers from 22Z-02Z. This may cause sudden wind
shifts around the terminal from any showers that do develop. Once
the convergence zone passes, the southwest winds will solidify to
northwest winds at 5 to 8 kt. MVFR ceilings will likely hold at MVFR
until after the convergence zone passes early this evening, then
look for some improvements to low-end VFR until early Tuesday
morning, as MVFR returns for the first part of the day.
HPR
&&
.MARINE...An upper-level trough will pass through the region today.
Gusty winds affecting small craft continue in the Central/East
Strait of Juan de Fuca and the Admiralty Inlet - expected to last
through late evening. High pressure will build off the coast during
the week, with troughing to the east. With strong northwesterlies
translating downward towards the surface, a couple periods of gusty
winds are possible in the outer coastal waters Tuesday evening into
Wednesday, as well as the central Strait of Juan de Fuca. A stronger
push looks probable Wednesday into Thursday for these areas, and
again Friday for the coast.
Seas will hold around 6 to 8 ft through Friday before increasing 8
to 12 ft from Friday into the weekend.
HPR
&&
.HYDROLOGY...The daily hydrology discussion has ended until the
start of the next rainy season; it will only be updated as needed.
&&
.SEW WATCHES/WARNINGS/ADVISORIES...
WA...None.
PZ...Small Craft Advisory until 3 AM PDT Tuesday for Central U.S.
Waters Strait Of Juan De Fuca-East Entrance U.S. Waters
Strait Of Juan De Fuca.
Small Craft Advisory until midnight PDT tonight for Admiralty
Inlet.
&&
$$
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