Area Forecast Discussion
Issued by NWS Medford, OR

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FXUS66 KMFR 211524
AFDMFR

Area Forecast Discussion
National Weather Service Medford OR
824 AM PDT Sat Oct 21 2017

.UPDATE...A quick glance at road cameras across the Cascades shows
that snow levels have risen above pass level, and therefore most
of the precipitation falling is now rain. Due to this, have
cancelled the Winter Weather Advisory a little early this
morning. Otherwise, the forecast remains on track, with gusty
winds continuing along the coast, over the higher terrain, and
across the East Side. Precipitation will gradually taper off
through the day, but winds will be slower to weaken, lasting
through this evening and into tonight.

For more information on this ans the rest of the forecast, see
the previous discussion below. -BPN

&&

.AVIATION...21/12Z TAF Cycle...Along the coast, MVFR/IFR
conditions with rain will persist through much of the TAF period.
Elsewhere, MVFR and occasional IFR and mountain obscuration is
expected to continue through this morning, then improve gradually
through the afternoon. Freezing levels will also rise through the
day from west to east, but showers are likely to continue through
the evening. Low level wind shear will be a concern through the
morning west of the Cascades. -BPN


&&

.MARINE...Updated 815 AM PDT Saturday 21 October 2017...A warm front
has moved north of the area, and gale force south winds are now
occurring over portions of the waters. These winds will diminish
later today, but steep west swell will persist into Sunday. A cold
front will move onshore Sunday. Once the front moves inland, a
thermal trough will set up, and this will bring strong north winds
and steep seas south of Cape Blanco beginning Monday and continuing
through Wednesday. -JS

&&

.PREV DISCUSSION... /Issued 329 AM PDT Sat Oct 21 2017/

DISCUSSION...

Everything appears on track with the warm front currently pushing
eastwards. Precipitation has begun to fall west of the Cascades
along with some snow occuring along the Cascades. The big stories
that we continue to highlight for the next 24 hours will be...

*Snow: Along the Cascades an additional 2 to 6 inches above 4500
       feet.
*Winds: Still windy along the coast, yet not strong enough for a
        wind warning.  Winds east of the Cascades 20 to 30 mph in
the late afternoon and evening with gusts to 55 mph.

As for the snow forecast, the snow levels are still on track to
jump up from 4500 to 9000 feet as the front passes. The biggest
impact here will be when the front passes the Cascades. That
appears to still be on track for 15Z this morning. The only
modification here is we forced snow accumulation into the
forecast from 12z to 18z above 4500 feet along the Cascades. Some
locations from 4500 to roughly 6000 feet did not have any snow
accumulation in the previous forecast.

As for the wind forecast, the 700 mb winds will be roughly 50 to
65 knots with the strongest winds farther north near Central
Oregon. All models are pretty consistent with this picture, so
feel very confident with the strong and gusty winds on the east
side this afternoon.

Eventually, the warm front will pass to the east, yet the the
strong west to east flow will continue to impact Oregon. The
majority of the rain is forecasted to fall to our north as the
moisture axis shifts north throughout the day. Therefore, during
Saturday night and Sunday morning, some locations will actually be
dry or just be under a slight chance for some rain. That moisture
axis will eventually shift south again Sunday and give us some
more wetting rain especially over the Coastal and Cascade range.

Into the work week, high pressure will build bringing back a
rather quiet weather pattern. With the clearing skies and all the
added moisture in the valley, expect fog in the morning hours.
This may impact maximum temperatures to be on the cool side even
with all the sunshine.

-Smith

&&

.MFR WATCHES/WARNINGS/ADVISORIES...
OR...Wind Advisory until 11 PM PDT this evening for ORZ030-031.

CA...Wind Advisory until 11 PM PDT this evening for CAZ085.

Pacific Coastal Waters...Small Craft Advisory from 5 PM this afternoon to 5 PM PDT Sunday
     for PZZ350-356-376.
     Gale Warning until 5 PM PDT this afternoon for
     PZZ350-356-370-376.
     Hazardous Seas Warning from 5 PM this afternoon to 5 PM PDT
     Sunday for PZZ350-356-370-376.

$$

BPN/JRS/CZS



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