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FXUS66 KMFR 261147 AAD
AFDMFR

Area Forecast Discussion...UPDATED
National Weather Service Medford OR
Issued by National Weather Service Eureka CA
447 AM PDT Thu Sep 26 2024


&&

.DISCUSSION...We are seeing a fairly benign area of high pressure
over the PACNW. Accompanied by a flattened upper level long wave
in the wake of yesterday`s frontal passage which now shows zonal
flow aloft. Last nights windy regime has eased, just before
another gusty spell is expected Friday over area coastal waters.
Temperatures will be normal for the late fall today with highs in
the lower 80`s and clear skies. Otherwise, it will be a pretty
typical fall day for southern Oregon and northern California.

Things become a little more interesting on Friday as a dry cold
front shoots down the coast and pushes into northern Oregon.
Temperatures here in southerly Oregon actually warm up into Friday
and Saturday and we should see another instance of the Chetco effect
in Brookings with some North east winds in that section of the
forecast area.

By this weekend, an upper level wave will move into the state of
Washington. Our area will see some cooler onshore flow and the coast
should trend cooler into the weekend. On the other side of things,
inland areas will remain in the upper 80`s with eastside locations
in the lower 80`s. It looks like another dry cold front will sag
into our area on Sunday. The NBM is predicting temperatures to trend
3 to 6 degrees cooler on Sunday afternoon as some of the cooler air
sags south.

We`ll have to monitor how strong the high pressure ends up being
Sunday night and Monday morning east of the Cascades. If we do see a
strong area of high pressure, it will become pretty hot and dry for
locations west of the Cascades on Monday with east flow off the
Cascades. The GFS does give hints of this, although we didn`t really
catch this looking at some of the 12Z ensemble data. In any case, it
will be something to watch.


&&

.AVIATION...26/12Z TAFS...Post frontal conditions have diminished
winds at most of the terminals. KOTH is seeing LIFR conditions with
low ceilings through the morning hours and light to calm winds along
with a lack of insulating upper clouds to hasten radiative cooling.
Obscurations will persist near the coastal terminals or near
coastal through the afternoon. The interior airports of Rogue
Valley and Crater Lake can expect VFR through the TAF period.


&&

.MARINE...Updated 4 AM, September 26, 2024...Steep northwest swell
will build into the area by Friday morning, and will continue
through Saturday. Meanwhile, the thermal trough will reestablish
itself along the coast Friday, producing gusty north winds and steep
wind-driven seas. This combination of conditions will result in a
period of chaotic and potentially hazardous seas Saturday, then on
Sunday, swell will diminish with winds possibly increasing to gales.
Overall, expect hazardous conditions through the weekend due to a
combination of strong winds and steep to very steep seas.

Winds and seas will ease a bit early next week, but continued north
winds and steep seas are likely to keep at least small craft
advisory conditions ongoing through at least mid-week. -BP



&&

.PREV DISCUSSION... /Issued 308 PM PDT Wed Sep 25 2024/

DISCUSSION...Once the front moves through, we`ll see more zonal
flow aloft as a weak area of high pressure sets in. Temperatures
will be normal for the late fall on Thursday with highs in the
lower 80`s and clear skies. Otherwise, it will be a pretty typical
fall day for southern Oregon and northern California.

Things become a little more interesting on Friday as a dry cold
front shoots down the coast and pushes into northern Oregon.
Temperatures here in southerly Oregon actually warm up into Friday
and Saturday and we should see another instance of the Chetco
effect in Brookings with some North east winds in that section of
the forecast area.

By this weekend, an upper level wave will move into the state of
Washington. Our area will see some cooler onshore flow and the
coast should trend cooler into the weekend. On the other side of
things, inland areas will remain in the upper 80`s with eastside
locations in the lower 80`s. It looks like another dry cold front
will sag into our area on Sunday. The NBM is predicting
temperatures to trend 3 to 6 degrees cooler on Sunday afternoon
as some of the cooler air sags south.

We`ll have to monitor how strong the high pressure ends up being
Sunday night and Monday morning east of the Cascades. If we do see
a strong area of high pressure, it will become pretty hot and dry
for locations west of the Cascades on Monday with east flow off
the Cascades. The GFS does give hints of this, although we didn`t
really catch this looking at some of the 12Z ensemble data. In any
case, it will be something to watch.

-Smith

AVIATION...25/18Z TAFS...An approaching weak front is pushing
MVFR/IFR conditions in along the coast and over the coastal waters
this morning. These conditions will push farther inland throughout
the rest of the day, with rain expected along the coast and into the
Umpqua Basin this afternoon and into the evening. Areas along the
coast and into the Umpqua Basin will see MVFR/IFR ceilings and
visibilities overnight and into tomorrow morning due to fog and/or
low stratus. Terrain obscurations are expected in these areas as
well, especially along the coastal mountains.

Other inland areas will remain at VFR levels throughout the next 24
hours. 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 calm in the late evening and overnight. -BPN/TAD

MARINE...Steep northwest swell will build into the area by Friday
morning, and will continue through Saturday. Meanwhile, the
thermal trough will reestablish itself along the coast Friday,
producing gusty north winds and steep wind-driven seas. This
combination of conditions will result in a period of chaotic and
potentially hazardous seas Saturday, then on Sunday, swell will
diminish with winds possibly increasing to gales. Overall, expect
hazardous conditions through the weekend due to a combination of
strong winds and steep to very steep seas.

Winds and seas will ease a bit early next week, but continued north
winds and steep seas are likely to keep at least small craft
advisory conditions ongoing through at least mid-week. -BPN

&&

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

CA...None.

PACIFIC COASTAL WATERS...None.

&&

$$

ZZZ/ZZZ/ZZZ