Area Forecast Discussion
Issued by NWS Seattle/Tacoma, WA

Current Version | Previous Version | Text Only | Print | Product List | Glossary Off
Versions: 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29

FXUS66 KSEW 241025

Area Forecast Discussion
National Weather Service Seattle WA
320 AM PDT FRI JUN 24 2016

.SYNOPSIS...An upper level low will move east of the Cascades
this morning...although wrap around moisture will still allow for
the chance for showers through the day today. Upper ridging will
start to build over Western Washington by tonight...bringing warmer
temperatures and drier conditions Saturday and into next week.


.SHORT TERM...IR satellite imagery shows the upper level low right
over Western WA at the time of this writing. While the radar imagery
is rife with weak echoes...there are two larger echoes with the best
likelihood for extending over much of King
County...likely ahead of the low center...and one over the Olympic
peninsula...west of the mountains...and that one is likely bringing
up the rear.

It is this junk in the to speak...that will be the main
concern for forecast today. Models remain consistent with moisture
continuing to wrap around the Low center for much of the day
today...keeping the chance for showers present over Western WA. By
this evening however...upper level ridging is still expected to
begin building over the area has likely been stated in many
previous discussions...will kick off a warmer...drier period
extending into next week. To stay focused on the short
term...heading into the upcoming weekend...the warming trend will
bring temps to the mid 60s along the water and a degree or two above
70 for the interior lowlands on Saturday. Sunday should prove
warmer...with around 70 near the water and mid to upper 70s in the
interior lowlands.

Inherited forecast covers all of the above only minor
cosmetic changes made.  SMR

.LONG TERM...Getting into the start of next week...models have begun
to introduce a shortwave for Monday. This does not look to have much
of an impact over the area...however...may result in very slight
chance pops over the Cascades. Kept POPs low for this feature for
now as this is only the second GFS run to feature this
solution...however...confidence is growing as ECMWF has seemed to
latch on to this as well. Temps look to peak on Monday before
dropping down a few degrees for Tuesday and Wednesday. Not so much
due to the aforementioned meager shortwave...but more likely to the
credit of the ridge axis shifting further east allowing for some
strengthening to the onshore flow. Still...this ridge looks to be in
place for a looking for a dry...warm week ahead.  SMR


.AVIATION...An upper low over Western Washington will move into
Eastern Washington this morning and then over Western Montana
this afternoon. An upper ridge over the offshore waters today will
move over Western Washington tonight. Southerly flow aloft will
become westerly behind the upper low today. At the surface,
onshore flow will prevail with high pressure offshore and lower
pressure inland.

The air mass is moist and slightly unstable with a mix of low and
mid clouds. A Puget Sound Convergence Zone over King County will
likely linger for a few more hours then break up late this

KSEA...A Puget Sound Convergence Zone is sitting just north of
the terminal early this morning with associated low clouds and
showers affecting the area. The convergence zone is expected to
weaken and break up later this morning but a batch of showers is
also expected to move in from the southwest around midday so low
clouds will probably persist most of the day. Southerly wind 5-10
knots. Schneider


.MARINE...Onshore flow will prevail for the next several days with
high pressure offshore and lower pressure inland. Small craft
advisory west winds are likely in the Central and East Strait
most evenings with this pattern. There will also probably be some
small craft advisory northwest winds for the coastal waters most
evenings starting Saturday as northerly gradients tighten a bit.


.SEW Watches/Warnings/Advisories...
PZ...Small Craft Advisory from 2 PM this afternoon to 5 AM PDT
     Saturday 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 11 PM PDT this
     evening for Northern Inland Waters Including The San Juan



You can see an illustrated version of this discussion at is the U.S. government's official web portal to all federal, state and local government web resources and services.