Etna, California 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

640
FXUS66 KMFR 202108
AFDMFR

Area Forecast Discussion
National Weather Service Medford OR
208 PM PDT Fri Sep 20 2024

.DISCUSSION...There are no major changes to the 7-day forecast
this afternoon, with quiet, mainly seasonable conditions of cool
to cold nights and warm to very warm afternoons. The items of
most signficant note are: breezy easterly winds over the Coastal
Range in Curry and western Josephine County into Monday with
downslope warming for Brookings, and a warming trend inland
Saturday into Tuesday with readings by Tuesday expected to be well
above normal (by about 10 degrees) but still generally several
degrees below the vicinity of record highs. Conditions for the
remainder of the coast will be near normal.

This is due to a pattern of high pressure centered offshore and a
trough in the Great Basin with a thermal trough near the coast.
This pattern will strengthen as the ridge builds into our region
and a trough develops over the southern California coast during
the weekend into early next week.

The pattern looks to change on Wednesday as a trough in the Gulf
of Alaska approaches the west coast and kicks the ridge inland.
There is uncertainty in the strength of the trough, but it is
highly likely that the bulk of precipitation will be focused north
of our area, with the highest probability in our area for western
Douglas and Coos counties late Wednesday into Wednesday night, and
a low/minimal probability of precipitation for south central
Oregon and northern California.

Another similar or weaker trough is expected around Thursday night
into Friday with a higher probability that rain will be strictly
limited to the coast, Douglas County, and northward. Besides the
risk of rainfall, the cloud cover and onshore flow pattern will
bring cooling for the second half of next week.

&&

.AVIATION...20/18Z TAFS...VFR conditions are expected (high
confidence) at the terminals throughout the valid TAF period. The
main concern tonight will be whether or not clouds impact the
terminals. Current analysis suggest we will lack low/mid level
moisture for clouds, but there is a low probability for cloud
development which could bring categorical changes tonight. MVFR
probabilities are around 10-20% for both Roseburg and North Bend
late tonight into tomorrow morning. Otherwise, confidence for both
Medford and Klamath is high these sites will remain in VFR
throughout this cycle.

-Guerrero

&&

.MARINE...Updated 200 PM Friday, September 20, 2024...A thermal
trough and associated pressure gradient along/near the coast will
remain in place through early next week; as a result, strong
northerly winds are expected through the afternoon and evening
hours, especially south of Port Orford where very steep seas and
occasional gale gusts are possible. Elsewhere, steep seas and
advisory strength northerly winds are expected north of Port Orford
through tomorrow. We are going to need an extension of the Small
Craft Advisory beyond Saturday night, but will reassess this after
the current hazards play out. Main reason for this is because
observations are suggesting wind speeds might be forecast on the
high side, so trended forecast wind speeds slightly lower over the
next 24-48 hours. If this trend holds, then a Small Craft Advisory
can be extended into early next week. However, there is a scenario
where the wind speeds are in fact going to remain strong and perhaps
stronger than the updated forecast, so we may need to consider a
Hazard Seas or Gale Warning. It will serve us well to wait another
shift or so to analyze the situation better, mainly conditions
south of Port Orford where the stronger winds are forecast.

The thermal trough is forecast to move inland with weakening winds
and easing seas late Tuesday into Wednesday. This will result in
relatively calm seas and light wind speeds through at least Friday.

-Guerrero

&&

.FIRE WEATHER...Issued 200 PM Friday September 20, 2024...A rather
quiet weather pattern is in store for the next 10 days. Dry weather
will continue through at least next Tuesday. Afternoon temperatures
will trend upward during this time with the warmest days Monday and
Tuesday as the upper ridge builds over the forecast area.

A thermal trough has set up along the coast and will remain a
fixture into the start of next week. The net result will be gusty
east to northeast breezes near and at the ridges at night into the
morning hours in Fire Zones 618, 619, and 620 with moderate
overnight recoveries. However due to the recent rains, fuels are
just not there, so there is little or no concern for critical
conditions. Looking at some ensemble data and comparing to the
climatology to this time of year, nothing jumps out as extreme.

There`s good agreement that an upper trough will push into the area
Wednesday morning along with a surface front which could bring light
precipitation to the northwest part of Fire Zone 616 and most of 615
Wednesday afternoon and evening, then drying out Wednesday night
into Thursday. Another front will brush by the northwest part of the
area late Thursday night into Friday morning, with the net result
being similar to Wednesday`s front. Afternoon temperatures
Wednesday, Thursday and Friday next week will trend lower and end up
being near normal for this time of the year for the interior.
-Petrucelli

&&

.MFR WATCHES/WARNINGS/ADVISORIES...
OR...CA...None.

PACIFIC COASTAL WATERS...Small Craft Advisory until 11 PM PDT
     Saturday for PZZ350-356-370-376.

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

&&

$$