985
FXUS66 KMFR 300454
AFDMFR

Area Forecast Discussion
National Weather Service Medford OR
954 PM PDT Sun Sep 29 2024

.DISCUSSION...Very warm and very dry weather will continue through
Thursday with a persistent thermal trough dominated pattern. This
includes a Red Flag Warning in effect through Tuesday morning for
the Coast Range of mountains in far southern Coos County and
southward into much of Curry, Josephine, and western Siskiyou
counties. Poor relative humidity recovery and gusty northeast
winds will affect the ridges in that area tonight and Monday
night, while all of that area will receive gusty northeast winds
and low RH in the afternoons. While not at critical levels
elsewhere, very dry and breezy conditions will be present across
our area.

The thermal trough is forecast to push inland on Friday, with
cooler conditions and higher humidity for the coast and Coast
Range, but continued very warm and very dry farther inland with
gusty southwest winds east of the Cascades. The outlook is for a
relatively dry trough to bring an increase in clouds and cooler
temperatures next weekend.

&&

.AVIATION...30/00Z TAFS...VFR conditions prevail across most of the
region for the next 24 hours. Gusty north winds will impact most
areas (but strongest along the coast, over the coastal waters and
into the Umpqua Basin) during the afternoon and evening hours.
Additionally, there will be gusty northeast winds over the coastal
mountains during the overnight/morning hours.  -CC

&&

.MARINE...Updated 800 PM PDT Sunday, September 29, 2024...Gusty
north winds will continue through Thursday under a persistent
thermal trough pattern. Seas will become wind wave dominated tonight
and persist into Tuesday. North winds are strengthening gales south
of Cape Blanco. Steep to very steep seas will persist through much
of the week with some improvement Tuesday as gales ease. This
improvement will be short lived, however, as another round of gales
will be possible again on Wednesday. Another moderate northwest
swell is likely to build Tuesday night, resulting in another episode
of potentially hazardous conditions due to combined wind wave and
swell into Thursday evening. Seas should diminish some as the
thermal trough weakens Thursday night and swell subsides.
-Hermansen/CC

&&

.PREV DISCUSSION... /Issued 431 PM PDT Sun Sep 29 2024/

DISCUSSION...The upper trough...which brought us cooler weather
today...continues to exit east out of the area as seen clearly in
the water vapor imagery. Temperatures this afternoon will be near
normal to slightly below normal for the end of September. Across
the area...temperatures are generally between 5 and 20 degrees
cooler compared to 24 hours ago...with the one exception being the
coast...where temperatures are similar to a few degrees warmer.
Another crazy swing in temperatures today for Brookings...yesterday
at this time they were running 16 degrees cooler compared to the
previous day...where now they are running 23 degrees warmer
compared to 24 hours ago. A roller coaster of temperatures!

This will be the last near to slightly below normal temperature
day for the foreseeable future as an upper level ridge of high
pressure over the eastern Pacific nudges east over the area.

Ridging remains in place...weakens some days to near zonal
flow...and then builds again. Either way...this will result in
above normal daytime high temperatures...generally 5 to 10 degrees
above normal on any given day for the next 7 days. Even looking at
the 25th and 75th percentiles for high temperatures...the spread
has decreased...meaning there is much higher confidence in the
extended forecast remaining warm.

Unfortunately...with warm temperatures...stronger east winds...low
relative humidity values...and poor recoveries...fire weather
concerns remain top of mind. Please see below for more
information.

No precipitation is forecast for at least the next 7 days.
Additionally...our friends at the Climate Prediction Center show
in their 8 to 14 day outlook (valid October 7th through 13th) that
east of the Cascades and northern California have a 30 to 40%
chance of below normal precipitation where the rest of the area
will remain near normal. Even at that...normal precipitation is
not much for the area this time of year.

-Riley

FIRE WEATHER...Issued 200 PM Sunday, September 29, 2024...

Warm, dry, and windy conditions are sort of the theme going forward
this week. This is especially true over parts of southwest Oregon
and northwest California where a Reg Flag Warning is in effect
tonight through Tuesday morning. Couple different things going on
here with poor overnight recoveries the next two nights, but we also
have low RH and windy conditions in the afternoon. We ended up
combining these threats into one warning starting tonight. The
pattern aloft will remain mostly zonal through the week with an area
of high pressure to our southwest over the Pacific. This area of
high pressure will slowly slide east each day. Eventually, an
incoming trough will kick this high to the Four Corners region.
Above normal temperature expected through most of this forecast with
only a small chance (<10%) for rainfall Friday into Saturday with
this system. This means we will likely deal with the wind associated
with that system rather than the rainfall. The thermal trough sticks
around until that system comes in, so we may need to consider
another Red Flag Warming if overnight recoveries remain poor with
strong east winds Tuesday and Wednesday night.

-Guerrero

&&

.MFR WATCHES/WARNINGS/ADVISORIES...
OR...Red Flag Warning until 11 AM PDT Tuesday for ORZ618>620.

CA...Red Flag Warning until 11 AM PDT Tuesday for CAZ280.

PACIFIC COASTAL WATERS...Small Craft Advisory until 5 AM PDT Tuesday
     for PZZ350-356-370-376.

     Gale Warning until 5 AM PDT Tuesday for PZZ356-376.

&&

$$