592
FXUS66 KMFR 142215
AFDMFR

Area Forecast Discussion
National Weather Service Medford OR
315 PM PDT Sun Jul 14 2024

.Updated to include FIRE WEATHER DISCUSSION...

&&

.FIRE WEATHER...Issued 300 PM Sunday July 14, 2024...

...RED FLAG WARNING REMAINS 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...

...RED FLAG WARNING IN EFFECT FROM 11 AM TO 9 PM PDT MONDAY FOR
ABUNDANT LIGHTNING ON DRY FUELS FOR FIRE WEATHER ZONES
620...621...622...280 AND 281...

...FIRE WEATHER WATCH IN EFFECT FROM TUESDAY AFTERNOON THROUGH
TUESDAY EVENING FOR STRONG GUSTY WINDS AND LOW RH FOR FIRE WEATHER
ZONE 281...

Thunderstorm potential remains the focus of the forecast efforts
through at least Tuesday. Strong high pressure will linger over the
Great Basin region into next week and a weak low pressure will move
northward just offshore of the California coast. This is a pretty
classic thunderstorm pattern for this area as the flow turns more
southerly and moist unstable air moves into the region.

Today is the big day in terms of most thunderstorm coverage. We
expect scattered thunderstorms across much of the East Side and
across northern California this afternoon and evening. Storms have
already started over western Siskiyou and eastward into Modoc
County. Cloud cover is limiting daytime heating over much of Lake
and some of Klamath County, but there should be enough moisture and
instability for additional storms to kick off this afternoon. A Red
Flag Warning remains in effect for these areas, and more details can
be found at RFWMFR.

As we head into Monday, storms look more isolated east of the
Cascades compared to today while the threat for areas west of the
Cascades has increased. We`ve decided to cancel the watch for FWZs
285/284/282 and upgrade FWZ 280/281 while also adding in FWZ
621/620/622. High resolution convection models are showing some
storms moving north from western Siskiyou County into Jackson and
Josephine Counties tomorrow afternoon. There is some concern for
nocturnal convection Monday night into Tuesday as low pressure
starts to move closer to the region. Confidence is rarely high for
these scenarios as models just don`t handle elevated convection
well. However, pattern recognition raises some concern for overnight
thunderstorms, potentially even West Side activity Monday night. Due
to low confidence, have left the mention of thunderstorms out of the
forecast for now, but it should be noted that the chance is not
zero.

For Tuesday, moisture is shifting northward and thunderstorm
activity will shift northward as well. The best chances for Tuesday
look to be across northern areas, but timing will be key as the
trough gets closer to the region. We`ll be in a bit of transition
pattern as drier air moves up from the south. The trough will be
taking on a negatively tilted orientation which is a common wind
maker pattern for us well. Strong gusty south winds are possible
across northern California and this could combine with low daytime
RHs to result in near critical to critical fire weather conditions.
for Tuesday afternoon. This could potentially include the Rogue
Valley, but confidence in thunderstorm potential limits confidence
in the strong winds/low RH potential as well.

Tuesday night into Wednesday, low pressure finally swings through
and out of our region. Given the negative tilt of the trough, it
could kick off some nocturnal storms again, but it looks more like a
situation where storms develop along the Douglas/Lane County border
and then moves north out of our area. Moisture looks to be well
north and east of the region on Wednesday, so thunderstorm chances
drop out of the forecast after Wednesday afternoon. /BR-y

&&

.PREV DISCUSSION... /Issued 254 PM PDT Sun Jul 14 2024/

DISCUSSION...The satellite picture looks similar to this morning
with the main difference of less stratus at the coast. Cumulus is
continuing to build with some activity in northern Siskiyou
County that is moving northward. Central/eastern Siskiyou County,
northwestern Modoc County and central/southern Klamath and Lake
counties have a 25-35% probability for lightning in this area, and
this is the most widespread lightning risk coverage that is
present. These thunderstorm chances will continue through 8-10 PM
tonight.

Overall, temperatures will be near 5-10 degrees above normal the
next few days, which will mean temperatures will still range from
50s and 60s in the mornings to 90s/low 100s in the afternoons
inland. The Rogue and Shasta Valleys and areas in western Siskiyou
County have an 85%+ probability to hit 100 through Tuesday. For
lows, last night`s temperatures were warmer than expected because of
the incoming cloud cover. Tonight`s temperatures were increased
slightly considering lingering cloud cover. The trend of warmer than
normal conditions will continue through the rest of the week. Please
still take precautions when having to be out in the heat this next
week.

The main smoke concerns lie in Siskiyou County with the Shelly Fire
while haze is present in other parts of Southern ORegon and Northern
California. This afternoon there will be southerly flow, and this
will bring more smoke of the Shelly Fire east into Modoc County and
southern Lake and Klamath counties. By morning, more of the smoke
will spread farther into southern Oregon, including Jackson County.

Monday afternoon`s chances for thunderstorms will be in similar
locations as today thanks to the upper level wave, but it will
extend into parts of Jackson and Josephine counties, including
Medford, Ashland, and Cave Junction.

Dry conditions are favored to return Wednesday. From Thursday
through the weekend, the probability for reaching 100 degrees in
Medford lowers to 25-45% while highs and lows are forecast to be 5-
10 degrees above normal. -Hermansen

AVIATION...14/18Z TAFS...This morning, despite the higher cloud
cover, VFR prevails over most of the CWA. However, IFR/LIFR marine
stratus/fog continues to impact the immediate coast and near shore
waters north of Cape Blanco and also south of Pistol River. These
lower conditions will continue to erode with clearing back to the
beaches expected for the afternoon. North winds pick up again this
afternoon, strongest from Cape Blanco to Pistol River with gusts up
to 35 kt, and gusts up to 25kt at North Bend. Expect stratus/fog to
return to the same coastal areas again early this evening, probably
around 00z at North Bend. Compared to today, the coastal IFR/LIFR
looks to be a little faster to erode later on Monday morning.

Isolated to scattered thunderstorms are expected this
afternoon/evening 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 Ashland. Gusty and erratic
winds are expected near thunderstorms today.

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.
-CC/DW

MARINE...Updated 230 PM Sunday, July 14, 2024...Steep to very steep
seas will continue at 5 to 9 ft at 7 to 8 seconds this evening.
North winds will be strongest this evening between Cape Blanco and
Nesika Beach from 3 to 20 nm from shore. North winds will trend
lower tonight into Monday. Even so, the main update is to extend the
low end Small Craft Advisory conditions expected late tonight
through Monday night with the mix of wind wave and fresh swell
producing steep northwest seas of 5 to 7 ft at 7 to 8 seconds.

Winds and seas will gradually subside Tuesday into Thursday. A
thermal trough is expected to return late in the week with steep
seas and advisory strength northerly winds possible.
-DW

&&

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

     Red Flag Warning from 11 AM to 9 PM PDT Monday for ORZ620>622.

     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.

     Red Flag Warning from 11 AM to 9 PM PDT Monday for CAZ280-281.

     Fire Weather Watch from Tuesday afternoon through Tuesday
     evening for CAZ281.

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

PACIFIC COASTAL WATERS...Small Craft Advisory until 2 AM PDT Tuesday
     for PZZ350-356-370-376.

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

&&

$$

ANH/MNF/DW