South Hill, Virginia 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

801
FXUS66 KSEW 191033
AFDSEW

Area Forecast Discussion
National Weather Service Seattle WA
333 AM PDT Sat Jul 19 2025

.SYNOPSIS...Upper level trough over Western Canada today sagging
south into Western Washington Sunday into Monday. Trough moving
east Tuesday. Flat upper level ridge building Wednesday then
weakening Thursday. Another upper level trough will move over the
area from the northwest Friday.

&&

.SHORT TERM /TODAY THROUGH MONDAY/...Satellite imagery shows
clouds filling in over most of Western Washington early this
morning. Weak low level convergence over Snohomish and Northern
King county just producing some cloud cover with no shower
activity present on the doppler radar. For the first time in a few
days everyone in the 50s at 3 am/10z.

Not a whole lot going on today. Weak convergence will dissipate
this morning leaving cloud cover over the Central Puget Sound.
Light onshore flow also pushing stratus deck east of Puget Sound
later this morning. Weak upper level trough to the north slowly
sagging south but still in Western Canada by late this afternoon.
Cross cascade gradients increasing to plus 8 or 9 mb later this
afternoon. This sets up a match up between the mid July sun
trying to erode the cloud cover and the increasing onshore flow
trying to enhance the marine layer. End result clouds hanging
around through the morning hours before giving way later this
afternoon for the interior. Clouds hanging tough along the coast
all day. Highs will be a little below normal, in the mid 60s to
mid 70s over the interior and lower 60s on the coast.

Little change in the pattern tonight with the upper level trough
to the north getting closer to the area. Low level onshore flow
will deepen the marine layer with mostly cloudy skies by sunrise.
Lows in the 50s.

Upper level trough moving over Western Washington Sunday and
remaining in place into Monday. Not expecting any precipitation
with this feature outside of a slight chance of showers or
thunderstorms late in the day both days in the North Cascades.
Upper level trough combined with low level onshore flow for
another mostly cloudy/partly sunny day Sunday. As the trough
starts to drift east Monday flow aloft becoming north
northeasterly. This will help to dry out the air mass over the
interior for more sunshine. Even with the sunshine Monday highs
remaining a little below normal, in the upper 60s to upper 70s for
the interior. A couple of degrees cooler for the highs Sunday.
Highs on the coast will remain in the lower to mid 60s. Lows both
nights in the 50s.

.LONG TERM /TUESDAY THROUGH FRIDAY/...Models not quite sure what
to do with the trough Tuesday. A majority of the solutions slowly
move the trough east of the area by the end of the day but there
is enough variability in the solutions to not be real confident in
this scenario. Highs in the 70s and lower 80s interior, 60s
coast.

Flat upper level ridge building Wednesday. Strong consensus among
the ensemble solutions that highs will warm. There are a non zero
number of ensembles that have the Seattle in the lower 90s. This
looks way too warm with low level onshore flow and 500 mb heights
only in the lower 580 dms. Normal high for Seattle increasing to
79 degrees Monday and will stay at 79 degrees until lowering to 78
on August 10th. This is the warmest time of the year. Will go a
few degrees above normal but cap highs in the mid 80s.

Weak ridge Thursday slowly transitions to a weak trough Friday.
No precipitation associated with the trough, just a little deeper
marine layer in the morning Friday. Highs in the 70s to lower 80s
Thursday cooling to the 70s Friday for the interior. Highs
remaining in the 60s on the coast.

Lows in the 50s every morning with possible low 60s in the metro
area Wednesday and Thursday morning. Felton

&&

.AVIATION...A broad upper level trough remains centered over British
Columbia today with west to northwest flow aloft over Western
Washington. Low level onshore flow continues. A deep marine layer
will encompass most of the lowlands this morning with widespread
MVFR ceilings. Ceilings will lift to VFR across most of the interior
lowlands by around 20Z with MVFR ceilings persisting along the coast
throughout the day ahead.

KSEA...MVFR ceilings are expected to persist through 18Z before
gradually lifting this afternoon, but not likely scattering out
until around 00Z. Surface winds S/SW 7 to 10 knots veering more
westerly late this afternoon.   27

&&

.MARINE...Broad surface ridging centered well offshore and lower
pressure east of the Cascades will lead to varying degrees of
onshore flow into early next week. Another upper trough approaching
British Columbia around the middle of next week is expected to
generate a stronger onshore push.   27

&&

.SEW WATCHES/WARNINGS/ADVISORIES...
WA...None.
PZ...Small Craft Advisory until 3 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.

     Small Craft Advisory from 3 PM this afternoon to 2 AM PDT Sunday
     for Central U.S. Waters Strait Of Juan De Fuca-East
     Entrance U.S. Waters Strait Of Juan De Fuca.

&&

$$