FXUS66 KMFR 231630
AFDMFR

Area Forecast Discussion
National Weather Service Medford OR
930 AM PDT Sat May 23 2026

...Updated the Aviation and Marine Sections...

.AVIATION...23/18Z TAFS

Areas of IFR will persist through this morning along the coast and
into the Coquille and lower Umpqua valleys. Otherwise, skies are
mostly clear.

Cumulus build ups are expected again this afternoon and early
evening, with isolated showers and thunderstorms from around the
Scott and Shasta valleys in Siskiyou County east-northeastward into
southern portions of Klamath and Lake counties, and also over the
Warner Mountains of eastern Modoc County.

Later, from around 06Z through 15Z Sunday morning, expect areas of
IFR/MVFR to redevelop along the coast, mainly from Cape Blanco
northward and from Gold Beach southward.

&&

.MARINE...Updated 815 AM PDT Saturday, May 23, 2026...A thermal
trough will continue to bring gusty north winds and steep seas
through Sunday morning. Winds will be strongest this afternoon and
evening. Seas may briefly become very steep this afternoon and
evening from Port Orford to Pistol River. But, winds near shore to
the south of Brookings will be weak today and become southerly. The
south winds will extend to Cape Blanco Sunday, and across the waters
with improving conditions Sunday night. A cold front will move
through the waters on Memorial Day bringing rain and increasing
seas. Swell dominated seas are expected to reach a peak on Tuesday
at around 13 to 16 ft at 14 seconds.

High pressure offshore and lingering low pressure inland are likely
to bring increasing north winds on Wednesday with gales possible
south of Port Orford. Gusty north winds are likely to continue steep
to very steep seas Wednesday night into Thursday while a long period
west-northwest swell builds.

&&

.PREV DISCUSSION... /Issued 359 AM PDT Sat May 23 2026/

DISCUSSION...

There is plenty of coastal stratus on satellite this morning with
some scattered mid level cumulus for yesterday's convection east
of the Cascades. With the thermal trough moving farther inland,
we'll see that coastal stratus linger most of the day along the
coast and some cooler temperatures there.

Farther inland, persistence is the name of the game with some
showers and thunderstorms developing this afternoon along the
California and Oregon border. The NBM had the PoPs around 10%,
although we increased them up to 15 to mention thunderstorms in
the gridded forecast. The ECMWF ENS members are all showing
something brewing along the California Oregon border this
afternoon. With some lingering instability, we'll likely see
isolated showers and thunderstorms this afternoon.

Zonal flow will continue with some embedded disturbances in this
flow pattern. Temperatures don't budge much, even with some
onshore flow west of the Cascades. The coast will be notably
cooler compared to locations farther inland. Some locations east
of the Cascades should still be well into the lower 80's.

A deeper trough will approach the region on Memorial Day and we'll
see some notable changes in the weather. Models and ensemble
members are in good consensus with a cold front arriving in the
afternoon and evening along the coast. Some locations will stay
dry through Memorial day, although locations along the coast will
see rain. As for areas farther inland, it's a little more
uncertain. Medford has a 40% chance of rain during the evening
hours 5pm-11pm.

It will also be breezy ahead of the front, especially east of the
Cascades with gusts around 30 to 35 knots. Forecast soundings
support deep mixing up to 600mb with lapse rates around 10C/km.
Winds up that high should easily be in the 30 to 35 knot range.
Some gusts to 40 mph seem fairly likely through the afternoon and
evening hours in Lake County.

After that, the low looks to become cut off around the region. The
persistent chance for showers and perhaps some thunderstorms will
continue through much of the week. Given the shear profile, it
might be a lot of pop up showers over the higher terrain. Overall,
beneficial rainfall for the region given how dry it has been this
winter and even the Spring.

-Smith

&&

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

PACIFIC COASTAL WATERS...Small Craft Advisory until 11 AM PDT Sunday
     for PZZ350-356-370-376.

&&

$$