724
FXUS66 KMFR 061151 AAA
AFDMFR

Area Forecast Discussion...UPDATED
National Weather Service Medford OR
451 AM PDT Sat Jul 6 2024

.DISCUSSION...Updated to add in a coastal section.

Excessive Heat Warnings remain in effect for west
side valleys through Tuesday evening, Heat Advisories for east
side valleys through Monday evening, Red Flag Warnings for much of
the area this afternoon and evening, and a Fire Weather Watch for
Sunday afternoon and evening.

Extreme heat is the theme through Tuesday, with very high
forecast confidence through that time. High pressure dominates the
pattern with hottest temperatures today, except on Sunday
temperatures east of the Cascades may be a degree or so higher
than today. There were several records set on Friday, 108 in
Montague, 85 in North Bend, 104 at Roseburg, and 109 at Medford.
Meantime, Klamath Falls and Mt. Shasta City ended up one degree
shy of their records.

Medford is representative of the slightly higher temperatures
expected today. The 00Z run of the NBM (National Blend of Models)
indicates a 75% probability that the high at Medford will exceed
110 today, with a large number of ensemble members clustered
around 111 to 113, and an official forecast high of 113, well in
excess of today`s record high of 104 set in 1922. It will be very
interesting to see what transpires, with the NBM indicating only a
5% probability of reaching or exceeding Medford`s all-time high
for any date of 115 degrees.

Accompanying this extreme heat into early next week, north to
northwest afternoon and evening winds will be near to slightly
stronger than the normal/typical breezes at 8 to 15 mph with gusts
up to 25 mph, except strongest at 15 to 20 mph with gusts to 30
mph in northern Lake County this afternoon and in the Shasta
Valley late this afternoon and Sunday afternoon.

Winds look to be slightly weaker Monday, then pick up again
Tuesday ahead of a broad trough. Temperatures and low humidities
will not be as extreme from Wednesday into next weekend, but still
noticeably warmer and drier than normal. Meanwhile, winds look to
trend slightly stronger, with winds toward the higher end of the
breezy scale at 10 to 20 mph with gusts to 30 mph.

For the coast, overnight low clouds look to be sparse into Monday
morning. Although, a few patches of fog have developed north of
Cape Blanco this morning and that same area should exhibit a
trend of slightly greater fog development each night through the
next week. A quick erosion of the stratus will follow. Meantime, a
relatively light northeast flow will persist south of Cape Blanco
through Monday with downslope warming for Brookings, wavering
between northeast and north flow through the week.

We are also vigilant regarding any risk of thunderstorms. Moisture
aloft still looks to be scarce during the next week, with a high
probability for conditions remaining dry. But, as early as
Wednesday afternoon there may be enough of a moisture influx to
allow some mentionable risk of thunderstorms for some portion of
the east side. From Wednesday into the end of the week, the ridge
axis is expected to shift east of our area. But, there are
significant model differences regarding the extent and timing of
two or three troughs moving east into the Pacific Northwest.

&&

.AVIATION...06/12Z TAFS...Atmospheric stability continues to
support mostly VFR conditions across northern California and
southern Oregon. Some light fog has lowered visibilites in North
Bend to MVFR levels, but this accumulation should clear out
quickly after sunrise. Clear skies will continue through the day,
with the possibility of marine fog returning north of Cape Blanco
early Sunday morning noted late in the TAF period.
-TAD

&&

.MARINE...Updated 200 AM Saturday, July 6, 2024...Wind-driven
steep seas persist in all waters today as northerly winds
continue. This afternoon, northerly winds will pick up in most
waters. The strongest winds will be angled to the southwest of the
cape, with sustained speeds of 25 kt and gusts up to 35 kt.
Lesser winds of 20 kt gusting to 30 kt will develop to the west
and to the north of Cape Blanco. These winds won`t be enough to
change the sea state but are still worth acknowledging.

Elevated winds south of Cape Blanco will continue into next week,
supporting a continuing Small Craft Advisory limited to these
southern waters through Monday evening. More widespread products may
be needed in the middle and end of the week as a thermal trough
strengthens, bringing gusty winds to all waters and possible periods
of gale gusts to waters south of Cape Blanco. -TAD

&&

.FIRE WEATHER...Issued 230 PM Friday July 5, 2024...Heatwave
underway and main concern for this period remains heat, winds, low
humidities and unstable conditions contributing to fire danger
through the weekend.

Worsening conditions are expected on Saturday with slightly hotter,
slightly drier, and slightly stronger winds expected across a
broader area, including east of the Cascades into zones 624 and 625.
The HDW (Hot Dry Windy) indices showing the condition as advertised
by the GEFS members to fall within the top 5% of these events over
the 30-year climatology from 1981-2010. In short, this is very
unusual to have the area this hot, dry and (breezy) for this time of
year. So, this occurring across the holiday weekend was the final
consideration. Despite no lightning, there will be other potential
sources of ignition.  A red flag warning is in place on Saturday for
zones 616, 617, 620, 621, 622, 623, 624 and 625 in Oregon and zone
280 in California. Brief or near critical conditions may also occur
in 281 and 282.

Hot, dry and gusty conditions continue into Sunday. Winds may trend
slightly lower though compared to Saturday but critical or near
critical conditions are again likely. So a fire weather watch
remains in place for these conditions.

The heat continues Monday and Tuesday. Additionally, a short wave
trough is advertised to come up the northern California coast which
is a pattern often supportive of thunderstorms. But, not seeing the
moisture to get us worried at this point and model guidance is
showing a only a very low chance (10% or less) for thunderstorms
Tuesday afternoon/evening and into Wednesday, mainly for the
Cascades east and Siskiyous south. Watch for updates on this
development.
-CC

&&

.MFR WATCHES/WARNINGS/ADVISORIES...
OR...Excessive Heat Warning until 9 PM PDT Tuesday for ORZ023>026.

     Red Flag Warning from 3 PM this afternoon to 8 PM PDT this
     evening for ORZ616-617-620>625.

     Fire Weather Watch from Sunday afternoon through Sunday evening
     for ORZ616-617-620>624.

     Heat Advisory until 9 PM PDT Monday for ORZ029>031.

CA...Excessive Heat Warning until 9 PM PDT Tuesday for CAZ080>082.

     Red Flag Warning from 3 PM this afternoon to 8 PM PDT this
     evening for CAZ280.

     Fire Weather Watch from Sunday afternoon through Sunday evening
     for CAZ280.

     Heat Advisory until 9 PM PDT Monday for CAZ083>085.

PACIFIC COASTAL WATERS...Small Craft Advisory until 9 PM PDT Monday
     for PZZ350-356-370-376.

&&

$$