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Area forecast discussion 
National Weather Service Seattle Washington
922 PM PDT Tuesday Oct 6 2015

Synopsis...a warm front will bring rain to the area Wednesday.
Thursday will be mild and mainly dry between weather systems.
A series of strong systems will give wet conditions to the area Friday
through Monday and it may be windy at times on the coast.


Short interesting and unusual weather pattern is expected
this week over the east Pacific. Due to the unusually very warm
waters east and northeast of Hawaii...hurricane oho...a fairly rare
Cat 1 hurricane with maximum winds of 75 knots and gusts to 90 knots is
expected to accelerate to the NE through the east Pacific toward
somewhere between central Vancouver Island and haida gwaii after it
transitions to extratropical Thursday into Friday. Latest ensembles from the
various hurricane and global models favor a landfall near the northwest tip
of Vancouver Island early Friday morning. Since the storm will be
extratropical as it moves by our area...maximum winds will expand
away from the center of the low. The latest nam12 and GFS solutions
show impressive 925 mb winds 85 knots just outside of our coastal
waters Thursday night and 50 knots in the coastal waters early Friday. Any
small deviation of the storm to the right of its projected path at
this time would result in high winds over the western olympic
peninsula and Washington coast. The latest models are a little to
the left of previous we will not issue a high wind
outlook at this time. But we will need to keep a very close eye on
this storms movement and transition.

In the mean time...infrared satellite images show deep moisture
offshore and rain is increasing over the coastal waters. Rain
chances will increase from the southwest overnight and a warm front
will bring rain at times to most of the area during the day on
Wednesday. Many locations will see 0.25 to 0.5 inches of rain...and
some coastal locations and the west side of the Olympics may see up
to an inch of rain. Rain will end from the southwest Wednesday night
behind the warm front.

Thursday will likely be a mild and dry -albeit cloudy- day as we sit
in the warm sector.

Current forecasts show only a chance of rain for Thursday night and
Friday. Latest model solutions are quite a bit faster with the
incoming remnant of later shifts may need to increase probability of precipitation
and quantitative precipitation forecast.

A quick update was sent out to refresh rainfall amounts and mountain
probability of precipitation. Otherwise forecasts through Thursday appear to be in good
shape. Albrecht

Long term...from the previous long term discussion...Sat through Monday
will see periods of rain as fronts pass through the region. The
timing and intensity is up in the air but a mild wet regime is
fairly certain to persist for several days. The moisture tap into
the tropics near Hawaii and possible leftover moisture from oho
could give periods of heavy rain with a chance of flooding in the
Olympics if the models become less progressive than current
solutions. Right now the plumes of moisture and wind have breaks
between them. 72 hour total rainfall from the uw wrgfs gets up around
five inches in the mountains...we have seen much more rain than that
in the mountains.


Aviation...a warm front will spread rain to western Washington as it lifts
north through the region late tonight into Wednesday. The flow aloft
is westerly...air mass is stable. Low level stratus remains on the
coast for MVFR ceilings. Over the interior just middle level moisture into
the early morning hours rain developing 09z-12z with ceilings
lowering down into MVFR 12z-15z. MVFR conditions continuing into the
afternoon hours.

Ksea...ceilings near 10000 feet slowly lowering to around 5000 feet
by 12z. Ceilings deteriorating rapidly around 15z down to near 1000
feet. Ceilings in the 1000 to 2000 foot range continuing into the
afternoon. Southerly winds 4 to 8 knots.


Marine...light flow at the lower level tonight. Southerly flow will
increase over the coastal waters on Wednesday as a warm front lifts
north through the area with Small Craft Advisory winds expected. A
second warm front will stall over the waters on Thursday. A series
of strong Pacific systems will arrive Friday through the weekend. The
first system on Friday will be the remnants of oho. This system will
still pack a strong punch even this far north with model 925 mb
winds as strong as 85 knots. Current model solutions track the low
well west of the coastal waters late Thursday night and Friday
morning. Even with the low moving to the west model 925 mb winds
over the coastal waters as high as 50 knots. Will go with solid gale
force winds in the forecast Friday morning. Additional systems will
arrive over the weekend into the Monday. Felton


Sew watches/warnings/advisories...





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