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Area forecast discussion 
National Weather Service Medford or
844 am PDT Tuesday Sep 2 2014

Update...other than a slight update to account for cloud and
smoke cover this morning, no changes to the previous forecast are
needed. Quiet weather, at least in terms of the public forecast, is
expected through the week, with dry and warm conditions remaining
in place. Main focus of efforts today will focus on fire and
marine forecasts, where critical and/or dangerous conditions are
expected. See the previous discussion for more information. -Bpn



&&

Aviation...based on the 02/12z taf cycle...IFR ceilings developed
overnight along the Coos and Douglas County coast and spread into
the Coquille Valley and northwest portion of the Umpqua valley. This
stratus will dissipate by middle-morning then return after 06z this
evening into Wednesday morning. Areas of reduced visibilities will
continue in western Siskiyou County due to smoke from wildfires.
Otherwise, clear skies will persist for the next 24 hours. -Dw



&&

Marine...updated 600 am PDT Tuesday 2 Sep 2014...north winds will
increase into this evening with Small Craft Advisory winds and steep
to very steep wind wave dominated seas of up to 15 feet. Winds and
seas will be highest over the outer waters south of Gold Beach, but
very steep seas will cover the area south of Cape Arago and beyond 5
nm from shore through Thursday night. The north winds will reach a
peak at gale force during Wednesday afternoon and evening, but are
expected to be nearly as strong during the other portion of the
period between this afternoon and Thursday evening. Winds along the
coast out to 5 nm are not expected to be as strong, however wind
driven seas from the outer waters will move towards the coast
causing them to be choppy. The thermal trough will shift west Friday
which will result in decreasing winds and seas. -Dw



&&

Previous discussion... /issued 309 am PDT Tuesday Sep 2 2014/

Discussion...very quiet weather over the forecast area this
morning with clear skies over the vast majority of the landmass
and a narrow strip of stratus along the north coast and adjacent
coastal waters. The surface thermal trough remains in place just
inland from the coast, but it will be sliding further east today
as a dry cold front moves through. This will shave a few degrees
off the west side temperatures today and produce gusty northwest
winds over most areas this afternoon.

A sharp but positively tilted short wave upper trough dropping
south along the British Columbia coast today will slide into the
Pacific northwest tonight and then off into The Rockies tomorrow.
Temperatures may be a couple of degrees cooler again tomorrow as a
result, but winds will be more northerly and probably not quite as
gusty in the afternoon.

The main trough axis then remains over US for the remainder of
the week and eventually morphs into a weak closed low in our
vicinity by week's end. Conditions remain quite stable with
rather impressive middle level capping while all this happens, so no
precipitation is expected and we may not even see much cumulus
formation through the week. This system will draw the thermal
trough back to the coast and then offshore, which will result in
increasing offshore flow in the low levels as well as increasing
heat later this week. This pattern is one where it can also get
hot at the coast, and that is one of the main forecast challenges
at this point: how hot to go at the coast later this week. We've
opted to stay conservative for now, but Thursday and Friday could
be quite hot at the coast if things line up just right, especially
around Brookings where a hot, dry Chetco effect is possible. The
most likely day for this looks like Thursday, but will keep an eye
on it.

Needless to say, the latter half of this week is going to be warm
to hot and dry all areas, which is a concern for fire weather. We
already have a Fire Weather Watch for portions of the area
Wednesday, and more fire weather watches/warnings may be needed
for later in the week as well.

The models still show a stronger trough moving into the Pacific
northwest late in the weekend or early next week. However, they
quickly build ridging in over the area thereafter. I wouldn't be
surprised to see the trough come to nothing more than a brief
respite in an otherwise hot dry pattern. -Wright

Fire weather...very active fire weather pattern this week starts
with the thermal trough moving inland Tuesday. This will bring
increased instability to the region...especially the Cascades...with
increased westerly winds on the west side. A dry cold front moving
through the region will also increase winds a bit. Behind the front
rh's drop quickly..especially at the ridge level with increasing
winds that become offshore across the east side by Thursday morning.
Cooler air aloft will move in Saturday...bringing increased
instability. However the flow preceding it is from the east and
there will not be enough moisture to allow any deep convection to
form.

&&

Mfr watches/warnings/advisories...
or...Fire Weather Watch from Wednesday morning through Wednesday
evening for orz623.
Fire Weather Watch from this evening through Wednesday evening
for orz621.

California...Fire Weather Watch from this evening through Wednesday evening
for caz280.

Pacific coastal waters...Small Craft Advisory for winds until 5 am
PDT Friday for pzz350-356-370-376.
Hazardous seas warning until 5 am PDT Friday for
pzz350-356-370-376.
Small Craft Advisory for hazardous seas until 5 am PDT Friday
for pzz350-356-370.
Small Craft Advisory for hazardous seas until 2 PM PDT Wednesday
for pzz376.
Gale Warning from 2 PM this afternoon to 8 am PDT Thursday for
pzz376.

$$

Bpn/trw/dw

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