027
FXUS66 KMFR 141108
AFDMFR

Area Forecast Discussion
National Weather Service Medford OR
408 AM PDT Sun Jul 14 2024

.DISCUSSION...

We set a few high temperature records yesterday with Montague
hitting 109 degrees, which broke the old record of 105 degrees.
Mt Shasta City also hit 104, which broke the old record of 99
degrees. With the arrival of some monsoon moisture, cloud cover
will help keep temperatures a few degrees lower on Sunday,
although many locations west of the Cascades will remain in the
upper 90`s and lower 100`s. Impact from the heat will trend lower
with the relatively cooler temperatures as we fall into a more
moderate HeatRisk for our region. Otherwise, this warmer than
normal trend will persist through the week.

Other than the persistent warmer than normal heat, smoke is always
a popular topic. With an upper level wave lingering off our coast,
upper level flow will still remain out of the southwest for the
next few days. This will result in smoke from the Shelly fire
continuing to move into the Klamath Falls area. The Scott valley
will continue to see plenty of smoke from this fire due to
relative proximity of the fire and low level westerly flow.

Things should begin to change around the end of the week with a
stronger northerly flow setting up sending the smoke to the south.
All of this depends on no new fires flaring up over the next few
days. This seems pretty unlikely given the thunderstorm activity
expected today and tomorrow after a pretty substantial heat wave.

The last topic is thunderstorms across the forecast area. More
moisture will arrive today ahead of an upper level wave and models
are anticipating scattered coverage across the forecast area. The
storm activity should remain in northern California and East of
the Cascades, although something could build up along the
Siskiyous this afternoon.

We can`t rule out isolated storms Sunday night as there is plenty
of mid level moisture and an upper level wave off the California
coast. There are also some ongoing at this time south of our
forecast area along the California coast. Thunderstorms will
persist into Monday with the main focus area in northern
California. It seems Oregon dries out a bit on Monday as a weak
ridge builds in overhead. The SREF has close to 0% lightning
probabilities across south central Oregon Monday.

By Tuesday, the upper level wave bringing all this thunderstorm
activity will finally depart the region. There could be some more cloud
to ground lightning around Douglas and Coos County Tuesday
evening based on the KOTH Forecast Soundings. Based on the
negative tilt of the upper level wave, we feel the threat for more
thunderstorms Tuesday evening is pretty reasonable.

-Smith

&&

.AVIATION...14/06Z TAFS...Isolated lightning in NE Siskiyou, Modoc
and into SE Lake counties earlier this evening has ended. There`s
still a slight risk of lightning overnight in those same areas as
moisture and elevated instability continue to push northward, but
dry weather persists west of the Cascades even if some higher level
clouds move in. Despite the higher cloud cover, VFR prevails over
most of the CWA. However, IFR/LIFR marine stratus/fog continue to
impact the coast north of Cape Blanco and also south of Pistol
River. These lower conditions will persist through about 17-18Z
on Sunday before clearing back to the beaches. North winds pick up
in North Bend again Sunday afternoon (up to 25kt). Expect
stratus/fog to return to the same coastal areas again Sunday
evening, probably around 00z at North Bend.

Expect another round of isolated to scattered storms Sunday
afternoon/evening with a larger coverage area from western Siskiyou
County northward up to the Siskiyou Mtns, southern Cascades (south
of Crater Lake) and then over to the east side again. Most activity
should remain east of the west side valleys, though can`t rule out a
stray storm in southern Rogue Valley near Ashland or up at Mt A.

Smoke from the Shelly fire in western Siskiyou County could bring
visibility reductions in the immediate vicinity of the fire with
MVFR visibility 15-25 miles away, especially to the NE (toward
Montague) as S-SW winds carry the main plume in that direction.
-Spilde

&&

.MARINE...Updated 230 AM Sunday, July 14, 2024...North winds will
trend lower today into Monday. Even so, conditions will remain
hazardous due to a continuation of moderate north winds and steep to
very steep seas, dominated by wind waves. A hazardous seas warning
remains in place through this evening for the very steep wind seas
from around Gold Beach southward and beyond about 10 NM from shore
(southern half of PZZ376). Models are showing a slight coastward
push to around 8 NM for seas near 10 feet between Gold Beach and
Port Orford Sunday afternoon, but it`s a small area and not
representative of the entire zone. A small craft advisory remains in
effect for the southern inner zone (PZZ356) for gusty north winds
and steep seas. The same is true for areas north of Cape Blanco,
where north winds and seas will produce conditions hazardous to
small craft. Tonight through Monday, winds and seas trend slightly
lower but expect continued areas of steep seas hazardous to small
craft.  Winds and seas will gradually subside Tuesday into Thursday.
-Spilde/CC


&&

.FIRE WEATHER...

...RED FLAG WARNING IN EFFECT UNTIL 11 PM PDT THIS EVENING FOR
ABUNDANT LIGHTNING ON DRY FUELS FOR FIRE WEATHER ZONES 280...281...
282...284...285..621...624... AND 625...

...FIRE WEATHER WATCH IN EFFECT FROM MONDAY MORNING THROUGH
MONDAY EVENING FOR ABUNDANT LIGHTNING ON DRY FUELS FOR FIRE
WEATHER ZONES 280...281...282...284...285...

The scattered thunderstorms are the big topic over the next 24
hours as more moisture arrives from the south and the atmosphere
isn`t as dry. The areas impacted by storms will also expand with a
northern and western push of all this moisture. Available
potential energy isn`t great, although it should be enough for
cloud to ground lightning across eastern and southern sections of
the forecast area. Therefore, no changes to the Red Flag Warnings
for today.

The one change that was made tonight was changing the start time
of the Fire Weather Watch on Monday in addition to removing the
Oregon zones from the watch. Although there is indeed convective
available potential energy, the probability of lightning is just
too low to justify a watch. The SREF lightning probability is
essentially zero over Oregon and the BUFR soundings do show some
CAPE, but is very shallow and might not even reach -15C and the
equilibrium level. As for the California zones, there is a little
more instability there and the HREF is more than happy to pain FWZ
280 with convection. This is also a hot spot climatologically, so
we kept the watch there and will let the next shift decide to
upgrade the California zones.

Finally on Tuesday, the upper level wave bringing all this
thunderstorm activity will finally eject northwards. This wave
will have a negative tilt, which usually brings some extra
dynamics and can overproduce convective activity when the models
just don`t buy it. Therefore, we added a slight chance of
thunderstorms in northern Douglas, Klamath and Lake Counties
Tuesday evening. Nocturnal storms are a serious threat here,
although they should be more of a problem north of our forecast
area.

-Smith

&&

.MFR WATCHES/WARNINGS/ADVISORIES...
OR...Red Flag Warning until 11 PM PDT this evening for ORZ621.

     Red Flag Warning until 11 PM PDT this evening for ORZ624-625.

CA...Red Flag Warning until 11 PM PDT this evening for CAZ280>282.

     Fire Weather Watch from Monday morning through Monday evening
     for CAZ280>282.

     Red Flag Warning until 11 PM PDT this evening for CAZ284-285.

     Fire Weather Watch from Monday morning through Monday evening
     for CAZ284-285.

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

     Hazardous Seas Warning until 8 PM PDT this evening for PZZ376.

&&

$$