Area Forecast Discussion
Issued by NWS Medford, OR

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566
FXUS66 KMFR 220358
AFDMFR

Area Forecast Discussion
National Weather Service Medford OR
858 PM PDT Mon Oct 21 2019

.DISCUSSION...
No updates are necessary this evening. Mostly clear skies are
expected to prevail through tonight except along the coast, much
of Coos County and northern Douglas County, and northern Klamath
and Lake counties where stratocumulus and cirrus clouds are
likely to result in partly to mostly cloudy conditions. This means
conditions should be good for most of us to see the Orionid Meteor
Shower, expected to peak tonight into early Tuesday morning.

A weakening cold front will push into the forecast area and
disintegrate as it does so Tuesday through Tuesday evening. This
will result in some increase in cloud cover for most of us, at
times, Tuesday and then an increase in northeast winds across the
area Tuesday night persisting into at least Thursday. BTL


&&

.AVIATION...For the 22/00Z TAFs...VFR conditions will prevail for
the remainder of the evening, except at the coast where MVFR
conditions will begin to build in. Fog and low level ceilings will
likely develop along the coast tonight bringing LIFR conditions. Low
level, IFR, CIGS will make it back into the Umpqua valley, yet we`re
not expecting fog formation near Roseburg tonight; conditions may
remain at MVFR, depending on how close any showers come to that
area. To that point, a weak front north of the North Bend and
Roseburg areas could cause light rain, reducing VIS. For Medford,
Klamath Falls, and east of the Cascades VFR will prevail through
this TAF period. -Miles

&&

.MARINE...Updated 840 PM PDT Monday 21 October 2019...High pressure
will keep marine conditions below small craft advisory criteria
through early Tuesday. A thermal trough over the south coast will
strengthen Tuesday evening with increasing north winds and steep to
very steep seas south of Cape Blanco. We have issued a Hazardous
Seas Watch for areas from Gold Beach southward beyond 20NM from
shore. Gusty winds and steep seas will expand northward and closer
to shore Wednesday. North winds and seas should lower some late
Thursday but this improvement will likely be short-lived. Winds and
seas will likely elevate again over the weekend, and gales are
possible south of Cape Blanco. Keene

&&

.PREV DISCUSSION... /Issued 251 PM PDT Mon Oct 21 2019/

DISCUSSION...The latest visible image shows most of the cloud cover
north of our area and offshore. Some high clouds are moving in from
the northwest into portions of Lake and Klamath County. A shortwave
near the Alaska panhandle will flatten our the upper ridge somewhat
late tonight into Tuesday. Meanwhile, a weak cold front will slowly
sink south towards our forecast area bringing at least a slight
chance of precipitation mainly north of the Umpqua Divide and
northern Cascades on Tuesday.

Any precipitation will end Tuesday evening with dry weather
returning Tuesday night and lasting through the end of the week as
upper ridging builds in. This will mean generally clear skies and
warmer than normal temperatures. This will be especially true along
the Curry coast where offshore flow and a potential Chetco effect
will set the stage for very warm weather. At the surface a thermal
trough will develop along the coast with increasing offshore flow.
In fact the pattern is favorable for a Chetco effect to take hold
and we could see high temperatures in Brookings and Red Mound in the
low to mid 80 degrees F Wednesday and Thursday. Guidance has trended
higher with max temperatures both days at Brookings and Red Mound
and max temperatures were adjusted higher. It will be warm
elsewhere, as well, with temperatures likely around 10 degrees above
normal.

Another upper trough will ride over the ridge Friday afternoon and
night with another cold front dropping south into the area. The
trajectory of the upper trough is one that is not favorable for
precipitation in our area. This is because there is not enough over
water trajectory. With that said, the operational ECMWF and a few of
the individual ECMWF ensemble members hint at some QPF over the
northwest part of the forecast area. Right now we have a slight
chance of showers for parts of northern Douglas County, but suspect
we won`t get anything. Depending on the timing of arriving
cloudiness, Friday will probably still be warm, but conditions will
cool down significantly this weekend into the start of next week
under cool, northerly flow. -Petrucelli

&&

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

CA...None.

Pacific Coastal Waters...
- Small Craft Advisory from 11 AM Wednesday to 11 AM PDT Thursday
  for PZZ350-356.
- Small Craft Advisory from 2 AM Wednesday to 11 AM PDT Thursday
  for PZZ370-376.
- Hazardous Seas Watch from late Tuesday night through Thursday
  morning for PZZ376.

$$

BTL/MB/MAP



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