551
FXUS66 KMFR 251156
AFDMFR

Area Forecast Discussion
National Weather Service Medford OR
456 AM PDT Wed Sep 25 2024

...Updated AVIATION discussion...

.DISCUSSION...The focus this morning was upon the details of an
approaching cold front. It is currently about 120 miles offshore,
will reach the coast this afternoon, and weaken as it tracks
across our area through this evening. It could be considered a
weak front in that it is only expected to produce a few hundredths
of an inch for the coast from Port Orford northward in the
afternoon and early evening, tapering to a trace of showers for
Roseburg with measureable amounts to the west, north, and
northeast of Roseburg. The remainder of our area is expected to
remain dry, with an increase of mid and high level clouds late in
the day.

On the other hand, it could be considered a strong front in that
it will most notably produce southwest to west winds of 15 to 25
mph with gusts to 35 mph across the east side and at exposed,
higher elevations of the Cascades. Peak gusts associated with the
passage of the front, should bring the strongest winds of up to
45 mph to the Silver Lake/Summer Lake area from 1 PM to 4 PM.

Lastly, it could be considered a moderately strong/typical front
in that high temperatures this afternoon will be around 8 to 24
degrees lower than yesterday, with the greatest change in the
vicinity of the strongest part of the front...for inland/Coquille
Valley portions of Coos County, and Douglas County, including
Roseburg.

While it may be next summer before we again approach the record
warmth of yesterday, after today (Thursday through at least
Tuesday), above normal temperatures and dry weather with
seasonably typical afternoon breezes will return. A very weak
front will dissipate as it reaches the coast late Thursday night
into Friday morning, with an influx of low clouds at the immediate
coast north of Cape Blanco as its only noteworthy impact. East
side afternoon and evening breezes will pick up a bit for Saturday
and Sunday at 15 mph with gusts as high as 30 mph as an eastward-
moving dry trough and front pass by to the north.

The 00Z GFS is on the stronger side, a decidedly minority view,
in comparison to the GEFS suite of ensemble members in regards to
the next cold front of note, expected around next Wednesday. The
blended model solution was utilized for the official forecast with
the probability of precipitation below 10% across our area. A
better chance of a wetting rain looks to be associated with the
following trough late next week around Friday Day 9/Saturday Day
10. -DW

&&

.AVIATION...25/12Z TAFS...Marine stratus continues to bring LIFR
levels along the Oregon coast. Ceilings are remaining solidly at
LIFR, with LIFR visibilities at Brookings and MVFR at North Bend. An
approaching front is pushing clouds inland, with stratus expected to
fill the Umpqua Valley later this morning. The front will bring
periods of scattered showers to Coos and Douglas counties this
afternoon. Low ceilings look to remain over these areas through the
TAF period.

Other inland areas will remain at VFR levels. Gusty winds will
affect areas east of the Cascades this afternoon and early evening
as the front moves to the east. Winds in these areas will return to
normal late tonight. -TAD

&&

.MARINE...Updated 230 AM ,September 24, 2024...Seas will remain
below advisory through the middle of the week. Northwesterly swell
remains elevated, but not by enough to build steep seas. A weak
front may bring scattered marine showers this afternoon and evening.
Thunderstorm chances with this front are in the single digits and
not a significant concern.

Northwesterly swell will decrease on Thursday before increasing
further on Friday and Saturday. Additionally, a dry cold front will
bring gusty northerly winds over area waters. This combination of
conditions will bring steep seas to most area waters on Friday
afternoon. Conditions will deteriorate Friday evening and through
the day Saturday as the thermal trough strengthens. With current
guidance, very steep and hazardous seas are possible south of Coos
Bay and beyond 10 nm from shore. There are 10-15% chances of gale
winds for Friday evening for areas south of Cape Blanco. Warning
products are a certainty, but confidence in timing and areal
coverage is moderate and will benefit from additional information.

Chaotic seas continue beyond Friday and Saturday with an additional
period of elevated gusty winds on Sunday evening. Winds and seas
will ease going into next week, but unsettled conditions are likely
to remain in outer waters at least. -TAD

&&

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

CA...None.

PACIFIC COASTAL WATERS...None.

&&

$$