Area Forecast Discussion
Issued by NWS Medford, OR

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000
FXUS66 KMFR 270232
AFDMFR

Area Forecast Discussion
National Weather Service Medford OR
630 PM PST Sun Feb 26 2017

Marine and Aviation sections have been updated...

.DISCUSSION...

.Short Term...Tonight through Wednesday Night...Currently, the
cold front lies draped across the area from the Applegate valley
northwest over Crater Lake and into far Northwestern Lake County.,
with the low centered just offshore at he mouth of the Columbia
River. Although the more steady precipitation is occuring along
the front, numerous showers are in line behind the front, and
these will continue to pass over the area tonight and well into
Monday. Snow levels are also lower on the back side of the front,
and we have had some reports of snow down to about 500 feet in
elevation, although the snow is melting quickly once the shower
comes to an end. Models have trended a bit weaker with this
system today, but any accumulations will continue to affect
travel. Will therefore keep the advisories and warnings in place.
For more information on these, see the winter weather message at
PDXWSWMFR.

Showers will continue into Monday morning, and snow levels are
expected to remain rather low. While the mountains passes and
other areas more prone to snowfall could pick up another inch or
two through Tuesday morning, the valleys floors are not expected
to pick up more than a half inch or so, if any at all.
Temperatures will stay on the cool side through this time, but
should begin to warm Tuesday as a ridge begins to build into the
region and precipitation comes to an end.

High pressure will then remain in control, with clearing skies
and slightly warmer temperatures through the remainder of the
short term. -BPN

.Long Term...Thursday through Monday...We`ll start off with a
broad area of high pressure across the region. This area of high
pressure will break down as a positively titled trough moves into
the Pacific Northwest. This area of low pressure, and high
pressure out over the Pacific will keep an atmospheric river
flowing for the majority of the extended forecast. This
atmospheric river event isn`t anything extraordinary, but it`s
long enough duration that flooding could be a concern sometime
down the line.

The bulk of the moisture in the atmospheric river appears to be
coming with a disturbance, which will be hovering over Hawaii on
Wednesday to Thursday. So this weak atmospheric river event will
have it`s breaks over the days, especially for the inland valleys.

The last thing to mention will be the potential for snow on the
Cascades next weekend.  Mid level flow at 500 mb is westerly with a
55 to 60 knot jet hitting the Cascades.  If this holds, this fits a
typical model of a Cascade snow event. -Smith

&&

.AVIATION...27/00z TAF CYCLE...
A cold frontal band will bring a 1-2 hour period of moderate to
heavy snow across the East Side east of Mount Shasta and Bly early
this evening resulting in brief LIFR to IFR conditions. Otherwise,
outside of showers across the forecast area, a mix of VFR and MVFR
is expected in the valleys. Tonight through Monday morning another
round of showers will move through bringing IFR to MVFR and local
LIFR in precipitation. Snow levels will fluctuate between 500 and
2000 feet tonight through Monday morning. There does remain a slight
threat of thunderstorms from the Coast Range westward into the
coastal waters through this evening. Showers will continue on
Monday, greatest in the later afternoon and evening. A mix of VFR
and MVFR is expected in the valleys, with local IFR in snow showers.
Throughout the period expect partial obscurations in the mountains
to become total, at times, as rounds of showers move through. BTL

&&

.MARINE...Updated 315 PM PST Sunday 26 February 2017...
There is a slight chance of thunderstorms through this evening as
cold low pressure continues to move southeastward through the area.
Fresh swell will continue to build steep combined seas to very steep
levels through early Tuesday morning with seas mostly in the 10 to
14 foot range. Showers will continue through Tuesday, and then a
weaker impulse will bring with it a slight possibility of showers
Wednesday. Thursday into next weekend another frontal system will
affect the area. Peak seas during that time period are expected to
be around 10 feet at 11 seconds. BTL

&&

.MFR WATCHES/WARNINGS/ADVISORIES...
OR...Winter Weather Advisory until 4 AM PST Monday for ORZ029-030.
     Winter Weather Advisory until 4 AM PST Monday for ORZ023-024.
     Winter Storm Warning until 4 AM PST Monday for ORZ025-026.
     Winter Weather Advisory until 4 AM PST Monday for ORZ027-028.
     Winter Weather Advisory until 4 AM PST Monday for ORZ026.

CA...Winter Weather Advisory until 4 AM PST Monday for CAZ082.
     Winter Weather Advisory until 4 AM PST Monday for CAZ080.

Pacific Coastal Waters...
- Small Craft Advisory for hazardous seas from 4 AM Monday to 4 AM
  PST Wednesday for PZZ350-356-370-376.
- Hazardous Seas Warning until 4 AM PST Monday for PZZ350-356-370-
  376.

$$

BPN/CZS/BTL


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