285
FXUS66 KMFR 070548
AFDMFR

Area Forecast Discussion
National Weather Service Medford OR
1048 PM PDT Sat Jul 6 2024

.DISCUSSION...Updated aviation section...

&&

.AVIATION...07/06Z TAFS...VFR prevails across the CWA for the next
24 hours. Winds ease and light fog or mist could develop along the
immediate coast late tonight or first thing Sunday. For now, keeping
VFR conditions at the coast with less than a 15% chance to fall to
MVFR visibility or ceilings. However, can`t rule out a drop to MVFR
or even briefly IFR. -Spilde/Hermansen

&&

.PREV DISCUSSION... /Issued 917 PM PDT Sat Jul 6 2024/

DISCUSSION...There were half a dozen records broken this afternoon
with Medford reaching 112 (previous of 104 in 1922) and Montague
right behind at 111. Tonight`s temperatures will be in the 60s
west side with 50s east side.

Current satellite shows the smoke from the Shelly Fire in Siskiyou
County is moving east towards Grenada, Greenview and Gazelle this
evening. To the northeast, Lake County has dust coming from Summer
Lake and surrounding lakes that are moving east/southeast, so
visibility reductions are possible.

Adjusted temperatures slightly for tomorrow afternoon as there was
only a 25% probability to see 110 in Medford. Overall the products
are still on track with heat products through Tuesday. -Hermansen

MARINE...Updated 830 PM Saturday, July 6, 2024...A thermal
trough will remain in place, but vary in strength the next several
days. Gusty north winds and steep wind-driven seas south of Cape
Blanco will continue tonight through Monday. Conditions hazardous to
small craft are likely to persist in those areas through mid next
week. More widespread products may be needed beginning Wednesday and
continuing through the end of next week as the thermal trough
strengthens, bringing gusty winds to all waters and possible periods
of gale gusts to waters south of Cape Blanco. -Spilde

PREV DISCUSSION... /Issued 249 PM PDT Sat Jul 6 2024/

DISCUSSION...A multi-day heat wave is in progress as a strong
ridge of high pressure remains in place over the region. This is
bringing very hot and very dry conditions to inland areas.
Dangerous, excessive heat remains the main concern into early next
week. Excessive heat warnings (NPWMFR) remain in place In
addition, breezy to gusty during the late afternoon and evening
are expected today. These winds combined with heat and low
humidities will result in elevated fire weather concerns across
many areas of southwest Oregon and into western Siskiyou County.
Breezy to gusty winds are forecast again on Sunday afternoon
evening, especially in Douglas, Joesphine, Jackson, southern
Klamath and western Siskiyou counties. Red Flag warnings are in
effect for these conditions today and Sunday. Please see the
RFWMFR and the fire weather discussion below for details.

With this heat wave the hottest temperatures are likely to occur
today through Monday, with afternoon high temperatures near or
above 110 degrees in many valleys west of the Cascades and highs
near 100 for valleys east of the Cascades. Overnight lows will
remain above normal as well with only brief or very little relief
from the heat. On Tuesday, a weak trough is forecast to move up
from California and this result in slightly less hot
temperatures. However, excessive heat is still expected into
Tuesday, especially across inland valleys west of the Cascades.
This is a multi-day heat wave with dangerous, excessive heat and
little nighttime relief. Record or near record high temperatures
are forecast including for Medford, Klamath Falls, Alturas and
Mount Shasta City today and potentially again on Sunday and
Monday.

For areas along the coast, expect little in the way of low clouds
except some patches of fog near Brookings and and north of Cape
Blanco are possible in the overnight and morning hours.
Temperatures will be above normal for coastal locations as well
with highs in the upper 70s to upper 80s through Tuesday.

As the shortwave trough moves up from the south beginning
Tuesday, we are watching for any risk of thunderstorms. Moisture
aloft still looks to be scarce with a very low chance (5%) for
thunderstorms from the Cascades east and Siskiyous south. A broad
tough moves into the region from the west mid to late week. This
will allow temperatures to trend less hot. There also a continuing
low chance (5%) for thunderstorms, mainly across northern
California or from the Southern Oregon Cascades east. Confidence
is low in the details during this period.

FIRE WEATHER...Issued 200 PM Saturday July 6, 2024...Heatwave
underway and main concern for this period remains heat, winds, low
humidities and unstable conditions contributing to fire danger
through the weekend. The combination of wind and low humidity is
expected to reach critical conditions for inland areas along and
east of the Interstate 5 corridor today. Forecast humidities range
from the upper single digits to low teens and winds range from
sustained 6-12 mph with gusts to around 20 mph. A red flag warning
in in place today for portions of zones 616, 617, 620, 621, 622 and
623, 624, and 280 for today.

Conditions on Sunday will be very similar to today, although winds
are forecast to be much weaker east of the Cascades. Given the
recent holiday, and despite no lightning in the forecast, there will
continue to be other potential sources of ignition, and rapid spread
of any new or existing fires will be a significant concern. A red
flag warning has been issued for Sunday for zones 616, 617, 620,
621, 622, 623, and 624 in Oregon and zone 280 in California. Brief
or near critical conditions may also occur in 281 and 282.

Heading into Monday, a weak upper level wave is forecast slide
through the region, and temperatures are expected to cool be a few
degrees, while humidities improve my a few percentage points. This
is expected to be just enough improvement to preclude additional Red
Flag issuances, but conditions will be borderline, and just close
enough to still warrant some concerns.

The heat continues into next week. Additionally, by midweek, 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/BPN

&&

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

     Red Flag Warning from 2 PM to 8 PM PDT Sunday for ORZ616-617-
     620>624.

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

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

     Red Flag Warning from 2 PM to 8 PM PDT Sunday for CAZ280.

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

PACIFIC COASTAL WATERS...Small Craft Advisory until 9 PM PDT Monday
     for PZZ356-376.

&&

$$