883
FXUS66 KMFR 070542
AFDMFR

Area Forecast Discussion
National Weather Service Medford OR
1042 PM PDT Tue May 6 2025

...Updated AVIATION discussion for 06Z TAFs....

.DISCUSSION...High pressure will remain in control through late
this week. A weak front enters the area on Wednesday weakening the
high pressure but this is brief and high pressure strengthens
again late in the week. An upper trough/low will approach the area
Saturday and move inland Sunday into Monday, bringing a cooler
and showery pattern to the area.

* A weak front moves inland Wednesday and brings slightly less
 warm temperatures along with a 10-15% chance of light rain along
 coast north of Cape Blanco and Cascades north of Diamond Lake.

* Warmer temperatures are forecast Friday and Saturday.

* Cooler and wetter weather expected Sunday and Monday.

A strong high pressure ridge over the region and a surface
thermal trough are bringing very warm and dry weather to the area
today. The ridge axis will shift eastward Wednesday as an upper
trough in the Gulf of Alaska deepens southward, positioned off
the Pacific Northwest coast. A weak front will move onshore during
the day Wednesday. The National Blend of Models continues to show
this will bring a slight chance (10-15%) of light rain along the
coast and inland into portions of Coos County and northern/eastern
Douglas County as well as the south central Oregon Cascades north
of Diamond Lake. Timing for any light rain is expected late
Wednesday morning through Wednesday evening. However, rainfall
amounts would be very light, generally trace to 0.02 inches.
Temperatures will trend cooler but will remain above normal across
inland areas. The front moves east of the area on Thursday. Then,
high pressure strengthens on Friday. This will bring a warm up
with high temperatures peaking around 15 degrees above normal and
highs in the mid to upper 80s for valleys west of the Cascades and
in the upper 70s to low 80s for valleys east of the Cascades.

Warm and dry weather continues on Saturday. However an upper
trough deepens off the Pacific Northwest coast as a low pressure
system moves towards British Columbia. This low will send another
front into the area, with chances for rainfall developing across
the area on Sunday into Sunday evening. Models and ensembles show
good agreement with a second low and frontal system moving
towards the area from the west late Sunday. This low is forecast
to move into southwest Oregon and northwest California on Monday
and bring chances for light to moderate precipitation. Winds will
pick up ahead of these fronts with winds beginning to increase on
Saturday, then gusty southwest to west winds likely Sunday and
Monday. Additionally, there are low chances for thunderstorms on
Sunday and Monday, with a 10 to 15 percent chance of thunderstorms
east of the Cascades on Sunday and a 10 to 15 percent chance for
thunderstorms on Monday for many inland areas. Also on Monday,
snow levels may lower to 5000 ft, so periods of light snow are
possible over higher pass in the Cascades. However, impacts are
likely very limited due to warm ground temperatures. Temperatures
will trend much cooler Sunday and Monday with highs near or below
normal on Sunday and below normal on Monday.

&&

.AVIATION...07/06Z TAFs...Marine stratus has brought IFR ceilings to
North Bend and LIFR ceilings to Brookings. Guidance still suggests
periods of MVFR visibilities affecting North Bend early Wednesday
morning. Any decrease in visibility is expected to clear out later
in the morning. An approaching weak front looks to raise coastal
ceilings to MVFR this afternoon while also bringing MVFR ceilings
into the Umpqua Valley. Showers with this front will be generally
isolated to the coast north of Cape Blanco and the Cascades.

Inland areas will remain at VFR levels with clear visibilities and
high ceilings. Winds look to briefly increase in the Rogue Valley
and across areas east of the Cascades on Wednesday afternoon before
improving on Wednesday night. -TAD

&&

MARINE...Updated 830 AM Tuesday, May 6, 2025...Conditions gradually
improve today. However, seas will remain steep for the waters south
of Cape Blanco and in the outer waters south of Coos Bay through
this afternoon.

Conditions improve for all areas by early Wednesday morning, although
breezy north winds will persist through the week. Seas become less
steep this evening into Wednesday, becoming northwest swell
dominated (5 to 7 ft @ 11-13 seconds) for the latter half of the
week. Overall conditions should remain below advisory criteria from
Wednesday onward, though winds could approach advisory levels at
times Thursday and Friday south of Cape Blanco.


&&

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

PACIFIC COASTAL WATERS...Small Craft Advisory until 11 PM PDT this
     evening for PZZ356-370-376.

&&

$$