530
FXUS66 KMFR 200528
AFDMFR

Area Forecast Discussion
National Weather Service Medford OR
1028 PM PDT Thu Sep 19 2024

Updated AVIATION and MARINE Sections

.DISCUSSION...Upper ridging is building is nudging into the area
from the west as the upper low in central/southern California
continues to move south. Satellite image shows mostly clear skies
with a few high clouds moving in from the northwest as a weak
northern branch shortwave zips through northern Washington State.
It will be dry with milder temperatures this afternoon.

Tonight, marine stratus will make a return along the coast, north of
Cape Blanco and into portions of the Umpqua Basin. A thermal trough
will set up along the south Oregon coast tonight with offshore flow
that will be sufficient enough to keep the marine stratus offshore.

Friday through early next week will be dry with afternoon
temperatures trending warmer for the interior. The thermal trough
will remain in place along the south Oregon coast and the pattern is
one where we could see afternoon temperatures at Brookings get into
the lower to mid 80s, possibly the upper 80s Friday through the
start of next week. Tuesday, the thermal trough will build north and
weaken some allowing the flow to become weak onshore at Brookings,
therefore it should be cooler.

Upper ridging will build over the area Monday and Tuesday with
afternoon temperatures maxing out both these days, then the upper
ridge will shift east as an upper trough approaches from the west
Wednesday. This will result in cooler afternoon temperatures for
most of the interior along with gusty afternoon and early evening
breezes east of the Cascades.

The operational models and ensembles are in similar agreement
showing the upper trough moving into the area, with a weak front
pushing into the northwest part of the area. However, the ensembles
show a dry, stable southwest flow with the upper trough positioned
west of the forecast area. -Petrucelli


&&

.AVIATION...20/06Z TAFS...Overall, we expect VFR to prevail
across a large portion of the forecast area through Friday evening,
including at Roseburg, Medford and Klamath Falls.

Patchy marine stratus could impact the North Bend terminal for
a few hours late tonight and satellite imagery is showing some to
the north over Tillamook, heading south. Models still are showing a
slight offshore (NE) wind component, which may prevent the
stratus from reaching the airport. We`ve left in a temporary BKN010
ceiling 09-12Z, these but shouldn`t be long-lived, if they occur at
all. Expect VFR to prevail during the day Friday, but gusty north
winds (25-30kt) will redevelop in the afternoon. There is a chance
some MVFR ceilings also develop during Friday morning at Roseburg,
but these should also be brief and only a few hours at most.
-Spilde

&&

.MARINE...Updated 830 PM Thursday, September 19, 2024...A thermal
trough pattern will likely persist through early next week. This
will result in the strongest northerly winds south of Port Orford
during the afternoon and evening hours, with very steep seas and
occasional gale gusts at least into Saturday evening. Meantime,
steep seas and advisory strength northerly winds are expected north
of Port Orford.

The thermal trough is forecast to move inland with weakening winds
and easing seas late Tuesday into Wednesday. -DW/Spilde


&&

.FIRE WEATHER...Issued 200 PM Thursday, September 19, 2024...
Pretty quiet weather will continue into this weekend as the flow
remains progressive out of the north west. A Weak disturbances moves
through the Pacific Northwest around Saturday before a stronger wave
moves through the state of Washington around Sunday.

The end result should be a notable north east to south west pressure
gradient with some stronger north east winds(15 to 20 knots),
especially over the Kalmiopsis wilderness. Looking at some
ensemble data and comparing to the climatology to this time of
year, nothing jumps out as extreme. There could also be some light
east breezes instead of stronger north east winds depending on
what ensemble cluster comes to fruition around Monday night. In
any case, Monday night is a period to keep an eye on, especially
for the fire weather conditions in the extreme southwest Oregon.

-Smith


&&

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

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

Hazardous Seas Warning until 11 PM PDT Saturday for PZZ356-376.

&&

$$