697
FXUS66 KMFR 262101
AFDMFR

Area Forecast Discussion
National Weather Service Medford OR
201 PM PDT Fri Jul 26 2024

.DISCUSSION...Seasonal temperatures continue across northern
California and southern Oregon this afternoon. An upper trough
remaining in place over Canada and the northwestern US is helping to
moderate temperatures in the short-term.

Wildfire smoke is going to be a significant concern for the
foreseeable future. The Park Fire in the Sierra Nevada foothills,
the cluster of fires in eastern Douglas County, and the Falls Fire
and the Battle Mountain Complex to the northeast are all possible
sources of smoke for the area. Light nighttime winds allow for smoke
to accumulate around a fire and spread out, while stronger afternoon
winds can guide a smoke plume over a localized area. This afternoon,
the Park Fire plume continues to move over Lake and Modoc counties
but overnight wind chances near the fire may push the plume to the
east and bring some relief. However, lighter winds will allow smoke
from the Douglas County fires to spread over areas east of the
Cascades. An Air Quality Alert is in place for Klamath and Lake
counties through Monday at noon. Intermittent smoke is expected in
Jackson, Josephine, and eastern Douglas counties. Smoke accumulation
beyond the Alert`s timeframe will be possible as these fires
continue.

Precipitation looks unlikely through the forecast period. There are
some slight 10% thunderstorm chances over southern Lake County and 5-
10% chances over Klamath County and along the California border.
Expected dry air aloft makes substantial rainfall look unlikely.
That makes these storms more of a concern for lightning strikes, and
thunderstorm possibility will be considered closely during future
analysis. An additional consideration for precipitation will be a weak
cold front that will move over the area from Monday afternoon to
Tuesday afternoon. Currently the chances of rainfall are 15-25%
along the Oregon coast and eastern Douglas county, with
precipitation amounts less than 0.1 inches expected where rainfall
does occur.

Long-term guidance shows an upper ridge developing in the wake of
Tuesday`s weak trough. Temperatures will warm quickly through
Wednesday and Thursday and are forecast to remain warm through next
weekend. Broadly, temperatures rise to the high 90s to low 100s for
west side valleys and low to mid 90s for areas east of the Cascades.
This is moving towards a return of heat products, especially for
west side valleys, by next weekend. HeatRisk guidance currently cuts
off on August 1st and does not indicate any Major or Extreme heat
through that day, but a trend towards increasing heat impacts is
clear in the guidance that is available. -TAD

Today we celebrate the retirement of Ken Sargeant, the Information
Technology Officer for Medford since 2002. Ken`s career started at
Santa Maria, CA in 1993 and has also included time as a Senior
Forecaster in Elko, NV. Ken has been at the forefront of NWS
advancements, including the deployment of dopper radar and being one
of the first group of ITOs. As Medford`s ITO, Ken has made sure that
we have the right software to provide the best forecasts to the
public. When things aren`t working, he`s been quick to diagnose and
fix the problem (after turning it off then on again, of course).
We`ve been fortunate to have both his support and his company here
at the Medford WFO, and we wish him all the best in the peace and
quiet that awaits him and his family.


&&

.AVIATION...26/18Z TAFS...Widespread VFR across the area early this
morning. Areas of IFR/LIFR stratus/fog have almost fully eroded
from the coast, but do still linger around Brookings.

In the immediate vicinity of the fires, visibility may be reduced to
IFR at times, but as west winds increase this afternoon and mixing
improves, much of it will be lofted, improving visibility. Smoke is
expected this evening at Klamath Falls, to a lesser extent at
Medford and unlikely at Roseburg, though there may be occasional
hazy skies across most areas. One area where persistent smoke may be
a problem all day is in southeast Siskiyou and southern Modoc
Counties, where smoke models indicate visibility could remain at or
below 3 miles due to smoke from the Park Fire.

IFR/LIFR marine stratus/fog at North Bend is expected to return this
evening around 03Z. -Miles

&&

.MARINE...Updated 200 PM Friday, July 26, 2024...A thermal trough
will remain in place through Saturday evening with north winds and
steep to very steep seas, highest from Gold Beach southward.  Winds
trend slightly lower tonight into Saturday, but steep seas linger,
especially south of Cape Blanco. The thermal trough will weaken with
winds and seas gradually diminishing Saturday night as a weak front
brings south winds Monday into Tuesday. Calmer conditions are
expected Sunday into early next week. -Spilde/Miles

&&

.FIRE WEATHER...Issued 200 PM Friday July 26, 2024...An upper
trough will continue to move through western Canada and this will
increase mid-level flow area-wide today. Meanwhile, a mid-level
weak low will push northward over our ridge of high pressure today
through Sunday. As a result, we are expecting some gusty west to
southwest winds of 15 to 20 mph with gusts to 30 mph to develop
this afternoon/evening over the eastside. Given the dry RH values
dropping down into the teens and single digits, have issued
another Red Flag Warning for Strong Gusty Winds and Low RH for
southeastern Oregon Fire Zone 625, southern Oregon Fire Zone 625,
and north central California Fire Zone 285 from 2pm until 8pm
tonight.

In addition, this low could bring an isolated shower or
thunderstorm to areas along and east of the Warner Mountains in
Modoc and Lake Counties Saturday morning through Saturday evening.
In general, do not think this pattern will rise to the level of
meeting critical conditions for scattered thunderstorms, so no
products are expected at this point.

Otherwise for this weekend and early next week, expect typical
afternoon breezes and warm and dry conditions to persist, although
temperatures will cool slightly to near or slightly below normal
values for this time of year. This means that near critical winds
and humidity values will be possible.

Mid week, another low pushes through which could bring some light
rain to the Oregon Coast and Cascades, but chances are that this
rainfall will not be wetting. More likely is that this system will
bring about stronger winds, but also higher humidities for a
little while as well.  -Schaaf


&&

.MFR WATCHES/WARNINGS/ADVISORIES...
OR...Red Flag Warning until 8 PM PDT this evening for ORZ624-625.

CA...Red Flag Warning until 8 PM PDT this evening for CAZ285.

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

     Small Craft Advisory until 5 AM PDT Sunday for PZZ356-376.

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

&&

$$

TAD/BPN/MCB