342
FXUS66 KMFR 070348
AFDMFR

Area Forecast Discussion
National Weather Service Medford OR
848 PM PDT Fri Jun 6 2025

...Updated the Marine Section...

.AVIATION...06/00Z TAFs...VFR conditions prevail for now, although
stratus is clinging to parts of the coast and is expected to expand
more inland through this evening, bringing the return of IFR/LIFR
ceilings. Gusty winds continue at the coast and are not going to
weaken until this evening, although they will still be breezy along
the coast near North Bend. -Hermansen

&&

.MARINE...Updated 800 PM Friday, June 6, 2025...Gusty winds
continue across area waters, with the strongest winds continuing
south of Cape Blanco. These winds are sustaining steep seas north of
Cape Blanco and very steep and hazardous seas south of Cape Blanco
through tonight. Winds and seas improve on Saturday, with all areas
having steep seas on Saturday morning. By Saturday evening, area
waters will be below advisory level although some isolated areas of
steep seas may be present south of Cape Blanco.

On Sunday, fresh northwest swell from elevated winds to the north of
this area will arrive in area waters. This swell may build steep
seas in area waters on Monday morning. Late Monday into Tuesday, a
thermal trough is forecast to build and bring gusty winds to waters
south of Cape Blanco. These winds may build very steep and hazardous
seas in waters south of Cape Blanco by Tuesday night. Steep to very
steep seas look to continue into late next week. -TAD/DW

&&

.PREV DISCUSSION... /Issued 454 PM PDT Fri Jun 6 2025/

DISCUSSION...Satellite image shows clear skies with a thin layer of
high cirrus moving in from the north for the interior. Along the
coast, marine stratus is from about Cape Blanco north and Gold Beach
south.

There`s good agreement for strong upper ridge to gradually move east
towards the end of the week into early next week. This will likely
result in afternoon temperatures heating up for the interior.
Afternoon temperatures for the interior westside valleys could flirt
near the tripe digit mark Saturday, Sunday and next Monday.

It will be dry most of the time and for most locations into early
next week. However there`s some evidence suggesting mid level
moisture creeping into northern California as a weak upper low
drifts from the west towards the Bay Area Saturday. Instability
parameters are marginal and there could be enough of a trigger for
isolated thunderstorms to pop up Sunday afternoon and lasting into
Sunday evening for portions of norther Cal, southern Cascades and
portions of the eastside. Although current data suggest instability
will be most favorable in western Siskiyou County.

Any storms should fizzle out later Sunday evening with dry weather
Sunday night into Monday morning.

The weak upper trough is expected to move into the area Monday with
the best instability in portions of northern Cal and along and east
of the Cascades. Therefore could not rule out isolated thunderstorms
again Monday afternoon and early evening east of the Cascades and
portions of northern Cal.

Ofthe three days (Sunday, Monday and Tuesday afternoon and early
evening), Tuesday could be the one of most concern in terms of
thunderstorms. A stronger upper trough will approach from the west
and there`s good agreement the upper trough axis will still be just
offshore late Tuesday afternoon. This will put the area in a
favorable position for isolated to scattered thunderstorms along and
east of the Cascades and northern Cal, with the instability
parameters greatest in Western Siskiyou County. Given the position of
the upper trough axis and stronger trigger ahead of it could bring a
heighten threat for isolated strong to severe storms. Keep in mind,
this is still a ways out and the details could change, so stay tuned
for the latest updates.

It still looks like the mainly dry and hot weather may only be a 3
day event with gradual cooling starting next Tuesday.

Beyond Tuesday, the ensemble means suggesting weak upper troughing
to return the latter part of next week into Fathers Day weekend,
with temperatures near normal and it will likely be dry from later
Tuesday evening into next weekend. -Petrucelli

FIRE WEATHER...200 PM PDT Friday, June 6 2025...Dry and mostly hot
weather for the interior will continue through the start of next
week. Relative humidities will be low in the afternoon, with the
lowest values east of the Cascades and the interior westside
valleys. With lighter winds aloft and a more relaxed pressure
gradient, winds are not expected to be a significant concern.
However, we`ll still have the typical afternoon and early evening
valley winds for the interior westside valleys and portions of the
eastside. The exception will be near thunderstorms in the afternoon
and early evening hours Sunday into Tuesday where we could be
dealing with gusty and erratic winds.

The main concern ahead will be the potential for thunderstorms in
the afternoon and early evening hours Sunday into Tuesday, with
Tuesday possibly being the highest concern for isolated to scattered
storms. Details on this to follow below.

Current data suggest northern California could be at highest risk
for thunderstorms Sunday afternoon and early evening. This is where
instability is greatest and mid level moisture is highest. The one
thing that is lacking is a strong trigger, but it does exist.
However, that does not mean there is no risk for the Cascades and
eastside. Just that the risk is less.

Storms could linger into Sunday evening for the above mentioned
areas, then storms should diminish and towards or shortly after
sunset. There was some concern for overnight storms Sunday night,
but the data is not convincing enough to keep storms in for the
overnight period for a couple of reasons. One, the HREF pretty much
shows little or no chance for storms after 8-9 pm pst Sunday
evening, two instability parameters are marginal at best and there
is little or no trigger.

Monday morning will start out dry, then the threat for storms return
again for the afternoon and early evening hours. Guidance suggest
the best chance for storms will be centered in northern cal,
especially western Siskiyou County and southern Cascades (south of
Crater Lake). However, isolated storms cannot be ruled out for
portions of the eastside, mainly in Klamath County. The trigger is
on the weak side Monday, but guidance shows rather unstable
conditions in portions of Western Siskiyou county. This is being
supported by the HREF which shows a sliver of 40% in this area which
for our forecast area is a pretty significant number.

Because the trigger is rather weak, and instability diminishes, were
not expected storms to linger much after 8-9 pm pst Monday, with dry
conditions expected.

Based on the latest information, Tuesday could be the day of higher
concern for isolated to scattered afternoon and early evening
thunderstorms. A slightly stronger upper trough will move in from
the west and there`s fairly good agreement the trough axis will be
just off the Oregon coast late Tuesday afternoon. This will put the
area in a more favorable position for some storms be strong to
severe since the trigger is expected to be stronger and greater
instability.

One thing of note, thunderstorms Sunday and Monday may produce
little or no rain, with the exception for western Siskiyou County,
there the moisture source is expected to be greater.

Keep in mind, this is not locked in stone and were still a ways out,
therefore some of the details could change. While current fuel
conditions do not represent significant wildfire concerns on their
own, once we get past the hot weather this weekend into early next
week that could change if we have a significant mount of lightning.
Please use extra care when participating in activities that may
create sparks or embers. These can ignite fires that can quickly
grow out of control, especially around abundant dry or unmaintained
fuels

After Tuesday evening, the threat for storms will be over with and
the rest of next week will be dry with a gradual cooling trend with
temperatures near normal for the interior towards the end of next
week. -Petrucelli

&&

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

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

Small Craft Advisory until 5 PM PDT Saturday for PZZ356-376.

     Small Craft Advisory until 11 AM PDT Saturday for PZZ350-370.

&&

$$