Onion Mountain Lookout, Oregon Weather Forecast Discussion

352
FXUS66 KMFR 162142
AFDMFR
Area Forecast Discussion
National Weather Service Medford OR
242 PM PDT Tue Sep 16 2025
.DISCUSSION...Today has shown warmer temperatures this afternoon,
especially west of the Cascades. There is the chance to near the
record high for Roseburg this afternoon as the record is 93
degrees from 2008, and the expected high is 94 As of 2 PM,
Roseburg was sitting at 88 degrees. Tonight will be a warmer night
with temperatures around 5- 10 degrees above normal for mid-
September, equating to 50s west side and more 40s east.
Wednesday will have the warmest afternoon temperatures for areas
east of the Cascades as the thermal trough continues moving inland.
Newer guidance is favoring temperatures to stay warmer for the Rogue
Valley as well, with a 70-80% probability to see 90 degrees there.
Therefore, the Rogue Valley will still hit 90 degrees Wednesday
afternoon along with the Klamath River Valley.
Tropical Storm Mario is looking to interact with the main flow later
this week and cause an upper trough to the northwest to slow its
movement east. If there is enough interaction on Thursday, the next
chance for precipitation could be in the afternoon for northern
California. On Friday this 15-25% chance could expand northward into
the Cascades and east into Klamath and Lake counties. Siskiyou and
Modoc counties and southern Klamath and Lake Counties will have a 15-
20% chance for lightning as the low moves closer to the area. There
are still model disagreements with where the tropical storm heads,
and the Euro is bringing it more north giving the area more chances
Thursday/Friday while the GFS keeps it farther south. There is also
only some agreement on location for rain chances Saturday. While
models align more for Northern California to see rain Saturday, more
uncertainty lies near and east of the Cascades. For now, the areas
described above will have the lower chance for precipitation later
this week, and this will be monitored tomorrow as more CAMs come in.
Other than these rain chances, things will remain constant with near
to slightly above normal temperatures. The next timeframe to watch
for would be into the middle of next week as an upper trough swings
down into the PNW.
&&
.AVIATION...16/18Z TAFs...VFR conditions will prevail through the
TAF period for inland locations, and through the afternoon for
coastal locations. As onshore flow returns later today, marine
stratus will redevelop this evening and overnight, likely bringing
the return of LIFR conditions to the coast after 03z today. /BR-y
&&
.MARINE...Updated 215 PM PDT Tuesday, September 16, 2025...Below
advisory seas continue through Wednesday afternoon, then steep seas
build. Wednesday night the thermal trough builds, and gusty
northerly winds with possible gale gusts south of Cape Blanco are
forecast through Thursday evening. There is a 40-60% probability to
see gale gusts Thursday afternoon, so a Gale Watch is in effect
starting Wednesday evening through Thursday afternoon. Steep to very
steep seas will be found elsewhere north of Cape Blanco and in the
inner waters south.
&&
.FIRE WEATHER...Updated 200 PM PDT Tuesday, September 16,
2025...With an upper level ridge in place and a thermal trough
shifting inland today, seasonably hot temperatures and low daytime
humidities are expected this afternoon. Easterly flow weakens this
evening and onshore flow returns on Wednesday. Despite weakening
east winds, moderate to locally poor recoveries are expected again
tonight into Wednesday morning and over a more widespread area as
dry air remains in the region. We`ll continue to headline this in
the Fire Weather Planning Forecast (FWFMFR). With onshore flow
returning on Wednesday, daytime RHs will trend somewhat higher and
temperatures somewhat lower west of the Cascades. Conditions similar
to today will continue across northern California and east of the
Cascades for Wednesday. There will be another round of northeasterly
winds Wednesday night into Thursday morning, but recoveries will
continue the improving trend compared to early in the week.
Confidence remains low in the forecast for the latter half of the
week. Another upper level trough will approach the region on
Wednesday and this may result in some enhanced afternoon breezes for
inland areas with temperatures trending less warm Wednesday into
Thursday. The approaching trough looks to stall offshore in response
to the remnants of Tropical Storm Mario moving northward along the
California coast, then getting swept into the main flow over the
weekend. This pattern will likely bring a thunderstorm threat to the
region Thursday into Friday, though there`s some uncertainty in how
far north and west this moisture gets. As the moisture moves
northward, thunderstorms could return to portions of northern
California as early as Thursday, then potentially into portions of
the East Side on Friday. Despite this being 3-4 days out, models
still aren`t in good enough agreement to boost confidence in
location. Confidence is higher for northern California where we`ve
added a slight chance mention of thunderstorms for both Thursday and
Friday, but there are some solutions that bring storms into
Jackson/Josephine Counties and/or southern Klamath/Lake counties
while others keep thunderstorms confined south of the OR/CA border.
At this point it doesn`t look like a big lightning event, and in
coordination with local fire agencies, will just go with a headline
for this potential in the FWF unless the coverage of lightning
trends higher over the upcoming days.
Beyond Friday, another trough approaches the region over the weekend
and sweeps these tropical remnants east of the area. There will
likely be periods of enhanced breezes with this trough, but we don`t
expect any meaningful precipitation out of it...maybe some light
precip across far northern areas. Meanwhile a cut off low will
linger offshore of California, far enough west that we aren`t
concerned about a thunderstorm pattern. This will come into play
around mid-week next week as it too, finally gets swept up into the
main flow and potentially brings a more widespread appreciable
wetting rainfall in the September 23rd-26th timeframe. Details at
this time range of course are unclear, but numerous members in the
ensemble suite of solutions are pinpointing this timeframe as wetter
and cooler. Stay tuned as the time draws nearer. /BR-y
&&
.MFR WATCHES/WARNINGS/ADVISORIES...
OR...CA...None.
PACIFIC COASTAL WATERS...Small Craft Advisory from 5 PM Wednesday to
     11 PM PDT Thursday for PZZ350-356-370-376.
Gale Watch from Wednesday evening through Thursday evening for
     PZZ356-376.
Hazardous Seas Watch from Wednesday evening through Thursday
     evening for PZZ370.
&&
$$

NWS MFR Office Area Forecast Discussion