957
FXUS66 KMFR 061146
AFDMFR

Area Forecast Discussion
National Weather Service Medford OR
446 AM PDT Sun Jul 6 2025

.DISCUSSION...A stable air mass will persist today with areas of
early morning coastal stratus. The warming trend will peak on
Monday, but inland temperatures will remain above normal through
the week. Seasonably breezy winds also will continue. Afternoon
and evening thunderstorms return Monday through Wednesday with
isolated coverage Monday mostly in Siskiyou County, up the
Siskiyou Mountains and Cascades, and into Klamath County. The
convective focus has the highest probability to be in northern
portions of Klamath and Lake counties for Tuesday, with an
additional possibility of a second, shortwave induced region of
activity for northwest Siskiyou County (near Happy Camp), the
Applegate Valley, and over towards Oregon Caves. Uncertainty in
the forecast nudges up a notch for Wednesday, but a focus is
forecast for southern Lake County with weaker instability trailing
back into Modoc and southern Siskiyou counties. The coverage and
typical strength of these storms will not rival those of last
week, but they also look to produce lesser rainfall
amounts...heightening the risk of lightning caused fire starts.

Slight cooling at mid-week will be followed by dry easterly flow
Wednesday night into Friday morning with downslope warming for
Brookings, and overall hotter conditions for our area into the
weekend.

The pattern shifts responsible for the aforementioned conditions
begin with ridging from Nevada into our region, ahead of a closed
low off the northern California coast...near San Francisco. This
low will shift gradually northeast toward Cape Mendocino Monday
into Tuesday, then track inland across northern California on
Wednesday. Ridging is expected to extend from well offshore
northeastward toward Vancouver Island on Thursday with relatively
lower pressure over California...setting up the easterly low level
flow into Friday. A stable, westerly flow pattern is expected next
weekend with temperatures trending a bit higher, back to several
degrees above normal.

&&

.AVIATION...06/12Z TAFs...Clear skies will continue inland into
Monday morning, with seasonably breezy late day winds. Meantime,
northerly winds will be stronger near shore and at much of the coast
with late day gusts up to 35 kt. LIFR near Brookings and north of
Cape Blanco is expected to gradually erode by 17Z, but will return
around 04Z this evening into Monday morning. -DW

&&

.MARINE...Updated 200 AM PDT Sunday, July 6, 2025...A thermal
trough pattern will bring gusty north winds and building seas into
Monday. Steep seas south of Coos Bay are expanding northward, with
steep seas across the waters by this afternoon. Gales develop this
afternoon south of Port Orford, resulting in very steep and
hazardous wind seas that will persist into early Monday. Briefly
improving conditions are expected Tuesday into Wednesday, with the
thermal trough strengthening again Wednesday afternoon and likely
persisting into the weekend. -DW

&&

.FIRE WEATHER...Updated 200 PM PDT Saturday, July 5, 2025...An
upper ridge will continue to move in over the area for the
remainder of this weekend. This will bring dry, stable conditions
through Sunday with temperatures getting back above normal
levels.  On Sunday, there can be a few buildups over the SE
mountains (Warners) during the afternoon/evening, but there
won`t be enough instability/moisture to produce deep convection.
As such we`ve kept thunder out of the forecast. Otherwise, the
forecast will be for continued near to slightly above normal
temperatures, seasonal humidities, and the typical diurnal wind
patterns, although general east flow late this weekend into early
next week leading to drying, especially across the ridgelines,
where poor to moderate recoveries are possible.

Heat builds further Monday, and it will still be hot Tuesday with
high temperatures in the mid to upper 90s and even some readings
in the West Side/NorCal valleys exceeding 100F.

Low pressure will then develop off the California Coast setting up
just west of SF Bay Sunday night into Monday. This is a similar set
up to the pattern that brought convection to the area for several
days this past (last) week. One difference though is that the deep
southerly flow of moisture available during the last event appears
to be less with this one and, as such, a limiting factor for
convection. That said, latest guidance continues to show
at least a slight chance (15 to <25%) of thunderstorms each pm/eve
beginning Monday and continuing through Wednesday. NorCal seems to
be favored, but also portions of the Cascades and East Side. It
should be noted that model PWs with this potential convection are
around 0.50-0.75" (esp southern and eastern areas, where values
could be below 0.50" at times), so any high-based convection that
does develop might not produce any rainfall. We`ll continue to
monitor the guidance to hone in on lightning potential and areas
that stand the best chance over the coming days. The low will get a
kick onshore Wednesday and move through NorCal and into NW Nevada
during the afternoon/evening. Still could be activity in NorCal and
east of the Cascades then, but do expect drier westerly flow to move
in Wednesday night and the thunder risk to end. Expect slight
cooling Wed/Thu, but a return of hotter weather again by Friday.
There also could be a period of weak offshore easterly winds
Wednesday night through Friday morning. -Spilde

&&


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

PACIFIC COASTAL WATERS...Small Craft Advisory until 8 AM PDT Monday
     for PZZ350-356-370-376.

Gale Warning from 11 AM this morning to 8 AM PDT Monday for
     PZZ356-376.

&&

$$