NWS Medford, OR wrote its last area forecast discussion before the first event at Sep 2, 4:06 PM PST, 55 minutes earlier.
Area forecast discussion, Sep 2, 4:06 PM PST, 55 minutes before
Area Forecast Discussion
National Weather Service Medford OR
506 PM PDT Fri Sep 2 2022
.Updated Aviation Discussion.
.AVIATION...03/00Z TAFs...Along the coast and into the coastal
valleys. Marine stratus is likely to persist through tonight, with
the chance for patchy drizzle late tonight into tomorrow morning.
IFR to LIFR ceilings are likely, but ther's some evidence ceiling
could improve to VFR at North Bend late Saturday morning.
Inland, lower visibilities due to smoke from active fires remains
the main hazard. However, only very localized MVFR visibilities are
expected mainly with 5 nm of the fires such as the Rum Creek Fire.
Gusty low level westerly winds in southwest Oregon this afternoon
and early evening will greatly aid mixing with improved
visibilities, although a broader area of haze/smoke aloft will
persist over southwest Oregon and expand across Siskiyou County and
the Cascades into Klamath County. Otherwise, it will be VFR into
this evening.
The satellite image is already showing signs of the marine stratus
making progress inland resulting in MVFR stratus with patchy IFR
spreading into the Camas Valley and Umpqua Valley, including
Roseburg. By early Saturday morning, patchy MVFR is also expected to
make it over the Umpqua Divide into Josephine County, including the
Rum Creek Fire. -Petrucelli
&&
.DISCUSSION...A trough nearing the area with a high pressure
ridge inland is resulting in a tight surface pressure gradient
and gusty winds across inland areas. These winds combined with
low relative humidities are resulting in critical fire weather
conditions today. A red flag warning (RFWMFR) is in effect
through this evening for portions of Josephine, Jackson, Siskiyou,
Klamth, Lake and Modoc Counties. The strongest winds will occur
from central Siskiyou and the Cascades east.
*Fire Warning: A new wind-driven fire, Mill Fire, has developed in
the Weed area and a fire warning (FRWMFR) has been issued by
Siskiyou County Office of Emergency Services for residents in
Weed, Lake Shastina, and Edgewood. If you are in these or nearby
areas, please listen to and follow official evacuation orders.
*Red Flag warning for Josephine, Jackson, Siskiyou, Klamath, Lake
and Modoc Counties through this evening. For those in these areas,
please follow all fire restrictions. Avoid tossing burning
cigarettes on the ground, parking hot vehicles on dry vegetation,
and using equipment that can cause sparks. Find links to
restrictions at weather.gov/medford/wildfire. One less spark, one
less wildfire.
Late this evening and overnight, winds are forecast to lower
across the area. Then, on Saturday, the shortwave trough will
move inland. Temperatures will trend lower on Saturday for inland
areas and areas along the coast will see fog, low clouds and some
light rain. A marine push will bring low clouds into the Umpqua
Basin and increased overnight/morning humidities, especially to
areas west of the Cascades. Also models are showing a 5-10%
chance for very light showers along and just west of the south-
central Oregon Cascades Saturday morning. Additionally, models
show elevated instability and mid level moisture over northeast
Lake County. Cannot rule out a thunderstorm or two in this area
and have included this in the forecast for Saturday morning.
Saturday afternoon and evening, winds will be breezy to gusty. In
the Modoc area, expect a combination of gusty winds and low
humidities to bring elevated fire weather conditions again and a
red flag warning is in effect for this area on Saturday.
Areas of smoke will continue to affect inland areas through this
weekend. Areas west of the Cascades may see some improvement in
smoke. However this may be brief or limited in areal coverage. An
air quality alert (AQAMFR) is in effect until further notice for
Curry, Josephine and Jackson Counties. For the latest smoke
forecast go to weather.gov/medford/wildfire. For air quality
information, please visit fire.airnow.gov.
Warm and dry weather is likely Sunday into Monday. Then, as the
high pressure ridge strengths, temperatures will warm further
across inland area on Tuesday. This is followed by the potential
for another through to move inland Wednesday and bring gusty
winds. Models are showing significant variability with the
strength and track of this upper trough, which will factor into
the details for the wind forecast as well as whether any showers
or thunderstorms may develop over the area. Confidence is low in
where or how much showers/thunderstorms may develop over the area
on Wednesday.
&&
.AVIATION...02/18Z TAFs...Along the coast and into the coastal
valleys, IFR to LIFR ceilings will continue early this morning.
Ceilings will gradually lift later this morning to mainly IFR with
local MVFR as a weak cold front moves across. Clouds will thicken
this evening with IFR expected and patchy drizzle or light showers
possible into early Saturday morning.
Farther inland, lower visibilities due to smoke from active fires
remains the main hazard. However, only very localized MVFR
visibilities are expected mainly with 5 nm of the fires such as the
Rum Creek Fire. Gusty low level westerly winds in southwest Oregon
this afternoon and early evening will greatly aid mixing with
improved visibilities, although a broader area of haze/smoke aloft
will persist over southwest Oregon and expand across Siskiyou County
and the Cascades into Klamath County. Otherwise, it will be VFR into
this evening. During the evening, mainly MVFR stratus with patchy
IFR will spread into the Camas Valley and Umpqua Valley, including
Roseburg. By early Saturday morning, patchy MVFR is also expected to
make it over the Umpqua Divide into Josephine County, including the
Rum Creek Fire. -DW/Sargeant
&&
.MARINE...Updated 230 AM PDT Friday 02 September 2022...
Light winds and seas are expected to prevail into Saturday morning.
A thermal trough is expected to develop Saturday afternoon with
winds increasing near Brookings. The thermal trough will strengthen
along the coast Sunday into Monday with increasing northerly winds,
and seas that may become steep to very steep. Winds will be
strongest south of Cape Blanco. The outlook is for the thermal
trough to push farther inland Tuesday into Wednesday with winds
weakening slightly. -DW
&&
.FIRE WEATHER...Updated 220 PM PDT Friday 1 September 2022...Despite
a brief lowering of temperatures Saturday, dry weather with above
normal temperatures will continue through at least early next week.
A dry cold front will move onshore today with strong afternoon and
evening winds in most of Siskiyou county, including the Mill fire,
the Cascades, all of the east side, as well as most of Jackson and
Josephine counties including the Rum Creek fire. This, combined with
very low relative humidities, will create critical fire weather
conditions across much of the area with Red Flag Warnings in effect.
The southern Shasta Valley will see south winds with gusts in excess
of 35 mph at time through the afternoon before beginning to taper
off this evening.
A marine push is expected behind the front tonight into Saturday,
and thus higher humidities and improved recoveries are expected west
of the Cascades. Temperatures will decrease a few degrees on the
west side Saturday. But, it will remain very dry and windy over
Modoc County, where a Red Flag has been added. There could be
another round of strong winds and low relative humidity toward the
middle of next week.
&&
.MFR WATCHES/WARNINGS/ADVISORIES...
OR...Red Flag Warning until 11 PM PDT this evening for ORZ617-620>625.
CA...Red Flag Warning until 11 PM PDT this evening for CAZ280>282-284-
285.
Red Flag Warning from 1 PM to 7 PM PDT Saturday for CAZ285.
Pacific Coastal Waters...None.
&&
CC/CC/CC