Area Forecast Discussion
Issued by NWS Medford, OR

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000
FXUS66 KMFR 280441
AFDMFR

Area Forecast Discussion
National Weather Service Medford OR
841 PM PST Mon Feb 27 2017

.SHORT TERM...The forecast remains on track with a weak shortwave
moving over the area this evening into tonight. Moist onshore flow
with this disturbance is bringing numerous showers to the area,
the greatest activity concentrated from the Cascades westward.
Snow levels are currently around 2000 feet and are expected to
lower slightly to 1500 feet overnight, and locally lower down to
1000 feet and possibly 500 feet. Snow showers will be mainly
light in the valleys and models indicate the stronger showers
will be focused over the higher terrain in the coastal mountains
and in the Cascades. Snow accumulations are expected to be light
for lower elevations with generally less than an inch for
elevations below 3000 feet tonight through Tuesday morning. In the
Cascades and western foothills, where snowfall is expected to be
the greatest, expect 2 to 6 inches tonight into Tuesday morning. A
winter weather advisory remains in place for the foothills of the
Cascades in Douglas county. Please see the WSWMFR for details.


Models continue to show that showers will decrease Tuesday as a
weak ridge builds into the area from the west.


&&

.AVIATION...28/00z TAF CYCLE...
Showers will continue through the TAF period across most of the West
Side and mountains. Showers will be most numerous mainly in the
afternoon and evening hours, and least in coverage in the overnight
and morning hours. During the day MVFR is generally expected in
showers, while outside of showers VFR is generally expected.
Overnight through the morning hours most areas will experience MVFR
conditions, with local IFR. BTL

&&

.MARINE...Updated 305 PM PST Monday 27 February 2017...
14 second period west swell and a shorter period fresh northwest
swell will combine to keep seas steep through most of Tuesday
morning. Showers will continue into Tuesday morning followed by a
brief break of high pressure, and then more showers arrive again
under a weak southwest flow late Tuesday into Wednesday from a weak
front. The next series of more significant fronts will affect the
area Friday into early next week. Peak seas during that time period
are expected to be around 10 feet at 11 seconds. BTL


&&

.PREV DISCUSSION... /Issued 705 PM PST Mon Feb 27 2017/

DISCUSSION...

..Short Term...Tonight through Thursday Night...An extensive
area of clouds and showers remain in the area this afternoon, as
cyclonic flow resides overhead and moisture continues to stream
into the region. With snow levels hovering between 1500 and 2000
feet, most of the more populated areas west of the Cascades
should see more in the way of rain, but in some of the heavier
showers, snow levels could drop down to between 500 and 1000 feet.
Later today and tonight, a weak trough will pass overhead, and
its dynamics will support a brief intensification of the shower
activity, and the mountains and foothills will likely pick up a
few inches of additional snow. Upsloping will be strongest along
the foothills of the Cascades in Douglas County, and it is here
where a Winter Weather Advisory is in place through tonight. For
more details on this area, see the winter weather message at
PDXWSWMFR.

Showers will continue into Tuesday, but will decrease in coverage
and intensity throughout the day, and should come to an end
Tuesday night or early Wednesday morning as high pressure builds
and begins to clear the area. Some residual showers may occur
along the coast north of Coos Bay as weak systems pass to our
north, but the area should remain dry and on the cool side through
the remainder of the short term forecast. -BPN

Long Term...Friday through Monday...The operational models show
general agreement in the forecast period. However the GFS suggest
the upper low in the Gulf of Alaska will have a greater influence
in our area next Sunday and Monday by way of lower snow levels,
persistent precipitation and cooler temperatures. In contrast, the
ECMWF and Canadian suggest the upper low will have less influence
resulting in milder temperatures and higher snow levels. Despite
the differences, the storm track will be close enough to bring
precipitation to the forecast area, especially along and west of
the Cascades. It`s all going to come down to the timing
differences with individual fronts from Friday through Monday.
-Petrucelli

&&

.MFR WATCHES/WARNINGS/ADVISORIES...
OR...Winter Weather Advisory until 10 AM PST Tuesday for ORZ025.

CA...None.

Pacific Coastal Waters...Small Craft Advisory for hazardous seas until 10 AM PST Tuesday
     for PZZ350-356-370-376.

$$

CC


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