Area Forecast Discussion
Issued by NWS Medford, OR

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131
FXUS66 KMFR 222145
AFDMFR

Area Forecast Discussion
National Weather Service Medford OR
245 PM PDT Sun Sep 22 2019

.DISCUSSION...Rain continues to push it`s way through the forecast
area this afternoon with the main frontal band draped east of the
Cascades and into western Siskiyou County. The greatest amounts
so far have been focused along the coast and north of the Umpqua
Divide where amounts of 0.15" to 0.25" have been recorded.
Elsewhere amounts are generally less than a tenth of an inch so
far. Showers are moving in behind the front as the upper level
trough begins swinging through. Instability associated with this
trough will lead to isolated thunderstorms this afternoon for just
about the whole forecast area. Conditions will gradually dry
later this evening and overnight as the trough moves east and
ridging begins building into the area.

Monday into Wednesday, a warming trend is expected with temperatures
reaching normal values by Tuesday. For the majority of the area,
dry conditions will be in place through Wednesday and possibly
into Thursday. Upper level ridging nudges it`s way into the
forecast area during this time, but weak impulses riding over the
ridge may bring periods of increased cloud cover and even some
light rain/drizzle for portions of the the coast north of Cape
Blanco. Aside from this and patchy areas of fog during the
mornings, relatively benign weather will be in place through mid-
week.

On Thursday, a weak front will move through in the northwest flow
aloft. Models have trended drier with this front so the forecast
has been adjusted accordingly. The more noticeable aspects of this
front will be increased afternoon breezes and the beginning of a
cooling trend. Thursday will serve as a transition day as a strong
upper low digs over the PacNW Friday and into the weekend. There
are still considerable differences in the details between the
models, but confidence is increasing in a wetter and much cooler
weather pattern for next weekend. Snow levels down to 5000 feet
are certainly possible under the pattern advertised by current
model runs, and although confidence in precipitation amounts at
this time is low, it`s not out of the question for some snow to
fall at Crater Lake, Mt. Ashland and possibly down to Diamond Lake
and Lake of the Woods. Those with outdoor interests in the higher
elevations this weekend should be prepared for possible wintry
weather. Stay tuned for updates. /BR-y

&&

.AVIATION...For the 22/18Z TAFs...Expect MVFR/IFR conditions,
mountain obscurations, and rain as a front makes its way across the
area today and into this evening. There is a slight chance of
thunderstorms through this evening, but coverage should be isolated.
Showers will end in most areas by late evening, with low cloud and
fog developing again along the coast and into the Umpqua Valley by
early morning Monday. -Spilde/BPN

&&

.MARINE...Updated 800 AM PDT Sunday 22 September 2019...A cold front
will move through the waters today with periods of rain and a slight
chance of thunderstorms. Winds briefly turn southerly ahead of the
front, but then veer to northwest behind it, while remaining below
advisory level. Seas will build modestly through the day with this
frontal passage as higher northwest swell arrives.

The thermal trough will quickly redevelop early Monday and
strengthen into mid-week. Gusty northerly winds will produce steep
wind driven seas south of Port Orford early Monday morning through
Tuesday. The continued strengthening is likely to produce very steep
seas with gales possible south of Cape Blanco Wednesday into
Thursday with conditions hazardous to small craft spreading north of
Cape Blanco.

The first in a series of disturbances is expected around Thursday,
but winds are likely to remain gusty and northerly into next
weekend. -Spilde

&&

.MFR WATCHES/WARNINGS/ADVISORIES...
OR...None.

CA...None.

Pacific Coastal Waters...Small Craft Advisory from 5 AM Monday to 11 PM PDT Tuesday for
     PZZ356-376.

$$

MNF/BPN/SBN



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