606
FXUS66 KMFR 160545
AFDMFR

Area Forecast Discussion
National Weather Service Medford OR
1045 PM PDT Wed May 15 2024

.UPDATE...Updated the aviation section.

&&

.AVIATION...16/06Z TAFs...VFR conditions will prevail through the
TAF period for most locations. The exception will be along the coast
north of Cape Blanco and in the Umpqua Basin. The coastal IFR/LIFR
conditions will persist well into Thursday morning, possibly locally
into the afternoon. A weak marine push will also bring some patchy
IFR ceilings to portions of the Umpqua Basin as well, potentially
affecting Roseburg around 11Z to 17Z. These lower conditions should
improve to VFR by late Thursday morning

Otherwise, expect gusty, breezy low level winds again Thursday
afternoon, especially along the coast where north winds of 25 to 35
kts are expected. /DW

&&

.MARINE...Updated 800 PM Wednesday, May 15, 2024...A thermal trough
pattern will maintain gusty north winds and very steep and hazardous
wind driven seas through tonight. Seas will be steepest and winds
will be strongest, reaching gales, south of Cape Blanco during the
afternoons and evenings. North of Cape Blanco, very steep and
hazardous seas with gusty winds are expected, but remaining below
gale force.

The thermal trough pattern weakens some on Thursday and gales will
ease. Despite this subtle improvement, gusty winds and steep to very
steep and hazardous seas will persist through the end of the week.
Conditions may improve overall over the weekend as the upper level
pattern transitions, though expect conditions to remain hazardous to
small craft for areas south of Cape Blanco as northerly winds
continue. /BR-y

&&

.PREV DISCUSSION... /Issued 203 PM PDT Wed May 15 2024/

SHORT TERM...The rest of today through Thursday night...Offshore
flow (NE winds) due to a strong and persistent thermal trough
continues to bring sunny, warm weather all the way to the beaches of
far SW Oregon this afternoon. The NE winds are funneling down the
Chetco River Valley into Brookings and this is sending temperatures
into the upper 80s once again. Gusty north winds are occurring
farther north along the coast, so enough marine influence is keeping
temperatures there mostly in the upper 50s and 60s. Inland, aside
from some high, wispy clouds, skies are sunny and it`s another warm
afternoon. Most west side valley areas will top out in the 80s,
though some 90s will occur in the lower Klamath River Valley of
western Siskiyou County. Temps in the upper 70s to near 80F are
expected for areas east of the Cascades and in NE California.

Tonight, we`ll see a deepening marine layer and another marine
push, this time perhaps a little farther inland than last night.
This should result in low clouds and some fog again and even a
little mist/drizzle along the north coast and into the Coquille
Valley. Models are showing the moist layer to around 1000 feet, so
some clouds could make it all the way into the Umpqua Basin, or bank
up against the Umpqua Divide (about a 20-30% chance). Elsewhere, it
will be mainly clear.

Any low clouds should break up again on Thursday resulting in
another mainly sunny, dry day. Heights do lower a bit west of the
Cascades in advance of a trough moving in from the NW and the
thermal trough will weaken (at least briefly). While temperatures on
Thursday will be near or even a bit warmer than today from the
Cascades eastward, it will be near or even cooler than today over
the west side. With a bit more marine influence, it will be cooler
on the SW coast. The upper trough and a dry cold front will push
through Thursday night. This will bring a deeper marine push into
the Umpqua Basin with some clouds possibly reaching into the Rogue
Valley by Friday morning. -Spilde

LONG TERM...Friday 5/17 through Wednesday 5/22...The long term
forecast begins with a slight pattern change. While southern Oregon
and northern California will be mostly under the influence of a
ridge of high pressure for most of the weekend, a trough of low
pressure will dig southward over eastern Washington and Idaho. While
this will not bring rainfall to our area, this could cause breezy to
gusty northwesterly winds--particularly in the afternoons.
Additional troughs will dig southward following this trajectory, and
maybe a bit more southward over the weekend helping to keep us
somewhat cooler with additional afternoon breezes and some fair
weather cumulus clouds.

By Monday, an additional trough pushes southward, but this front
will be closer to central Oregon. This could bring additional breezy
winds, but also our first shower chances--particularly along the
higher terrain of the Cascades and coast range in Douglas and Coos
County. Rainfall will be relatively light, and thunderstorms are
generally not expected (less than a 10 percent chance).
Temperatures, however, will be several degrees cooler than over the
weekend.

Then on Tuesday into Wednesday, another low spins southward, this
time over western Oregon and could bring additional showers and
thunderstorms (chances are just less than 15 percent at this time).
Winds will continue to be relatively breezy and temperatures will
remain slightly below normal through mid-week. Since the weather
will be based on a low pressure system that has not formed yet, the
confidence is relatively low--especially since the impacts will be
tied to the location of the low. Used the National Blend of Models
and am forecasting the most likely scenario at this point since
clusters are in general agreement over the large scale and differ
over some of the smaller features. Keep an eye to the forecast for
updates. -Schaaf

&&

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

PACIFIC COASTAL WATERS...Gale Warning until 11 PM PDT this evening
     for PZZ356-376.

Small Craft Advisory until 11 AM PDT Friday for PZZ350-356-370-
     376.

     Hazardous Seas Warning until 11 PM PDT this evening for PZZ350-
     356-370-376.

&&

$$