Flood in Oregon, March 16, 2025

Area Forecast Discussion
National Weather Service Medford OR
441 AM PDT Sun Mar 16 2025

...Aviation Section Updated...

.AVIATION (12Z TAFs)...

A strong low level jet persists across the region this morning
with speeds around 60kt at roughly 1500-2000ft for inland areas.
Rain showers are also expected to impact the terminals today with
coverage becoming more isolated to scattered later this afternoon
and tonight. Generally looking at VFR to MVFR through this TAF
cycle.

-Guerrero

&&

.PREV DISCUSSION... /Issued 424 AM PDT Sun Mar 16 2025/

DISCUSSION...An atmospheric river event is well underway this
morning. Persistent onshore flow directed in a SW-NE fashion is
aimed directly into Lane, Douglas, Coos and Curry counties. Water
vapor imagery is showing the 300-400 mi wide band of high IVT (500
kg/m/sec) extending from the Oregon coast back to just north of
Hawaii, a strong indicator that the air mass is of subtropical
origin. This fire hose has been aimed at southern Oregon for the
past several hours, with the heaviest rainfall and highest
rainfall rates falling north of a line that spans roughly from
Crescent City across Medford to Crater Lake and into northern
Klamath County. In areas north of that line, 0.10-0.30"/hr
rainfall rates have persisted, but orographic ascent is aiding
precip production in the Curry Coast Ranges and is resulting in
some rates approaching 0.50"/hr at sites like Red Mound RAWS and
Flynn Prairie RAWS. There is a fairly sharp gradient in
precipitation totals so far. Over the past 6 hours (as of ~3 am
PST), totals north of that line range from 0.50"-0.75" for
portions of Josephine and Douglas Counties, 1.00"-1.50" along the
Coast and 1.50"-2.00" across the higher terrain of the Curry Coast
Ranges and the Rogue-Umpqua Divide. Meanwhile, south of that line
only a few hundreths to 0.10" have been recorded.

Overall, not much change in the current situation is expected
through the morning hours aside from some slight wobbling of the
front to the south. Hi-res models are showing precip rates could
peak between 12z-18z this morning, when some locations could see
up to 0.50-0.75"/hour rates, at least for a short duration of 1-3
hr. When all is totaled up, rain amounts of 3 to 6 inches will be
common along the coast, into the Umpqua Basin and over to the
Cascade Foothills. As mentioned earlier, orographic lift will
likely aid precip in the coast range mountains resulting in some
totals exceeding 8 inches. South of the Rogue/Umpqua Divide,
rainfall will likely be 1-3 inches, with the lower amounts
expected in the southern Rogue Valley. Many headlines are out for
the heavy rainfall, with areal flood watches up west of the
Cascades as well as many river/stream forecast point flood
watches/warnings. This includes Deer Creek at Roseburg, Elk Creek
at Drain, South Umpqua at Elkton, Coquille at Coquille, the South
and North Forks Coquille at Myrtle Point and the Rogue River at
Agness. Please see water@noaa.gov for the specifics on those
particular rivers and be on the lookout for more potential flood
advisories/warnings through the day today. Please do not drive
through flooded roadways. Most flood deaths occur in vehicles.
Turn around, don't drown.

Meanwhile, snow levels are hovering around 5000 ft in the
Cascades, and heavy snow is resulting in dangerous conditions. By
the time this event is over, snow totals will be measured in FEET
up at Crater Lake. Snowfall rates of 1"/hr up that way are nearly
certain with a 90-100% chance through the afternoon, and even a
60-90% chance of 2"/hr as well. Winter Storm Warnings remain out
for the Cascades/Siskiyous through this evening. Heavier precip
rates are keeping the snow level lower on Highway 97 north of
Chiloquin, whereas to the south, Klamath Falls and Lakeview are
both solidly in the warm sector with little or no precip. A winter
storm warning is out for northern Klamath and parts of northern
Lake County also through this evening. It should be noted, that
very strong winds are expected along with this heavy snow, and
periods of very low visibilities are expected. This is most likely
up in the Cascades and higher elevations east of the Cascades, so
it's best to remain out of those areas until this event is over.
Details on these winter weather hazards can be found at WSWMFR. An
interesting caveat to the snow level is on the back side of the
heavy precip later this morning/early afternoon. Models are
showing the snow level dropping to around 2500-3000 feet, which
could impact the Cascades Foothills (Highway 138 near Toketee
Falls) with a changeover to snow. So be aware of that possibility.
Some guidance is showing it getting down to 2000 feet, but the
probability of that occurring is very small (less than 10%
chance).

Speaking of strong winds, there is a plethora of High Wind
Warnings and Wind Advisories spanning the area. So far, gusts of
55 to 60 mph have been recorded along the coast, across the higher
terrain, the Shasta Valley and portions of the East Side/NorCal.
Meanwhile, gusty southwest winds are surfacing in parts of the
Illinois Valley and Umpqua Basin where we have a Wind Advisory in
place. Winds will gradually ease from northwest to southeast as
the day progresses, with an overall downward trend by this
evening. Please see NPWMFR for more details.

Another low pressure currently out near 140W will approach the
coast this afternoon, and be the catalyst for pushing this front
along. This will push the bulk of the precipitation south and
eastward, and areas east of the Cascades will get their share of
precipitation late this afternoon and evening. Snowfall will ease
up along the Cascades, and we'll likely see a transition from rain
to snow over the East Side as the frontal boundary presses east
of the Cascades this evening. This transition is likely to happen
as the heavier precipitation is easing up over there, so while
there may be some heavier snow amounts in the higher terrain,
snowfall overnight tonight will be fairly light with generally 1-2
inches expected tonight through Monday. The exception could be
along the Warners of Modoc County where advisory level snow
amounts are possible and could impact Cedar Pass on Highway 299.
For areas west of the Cascades, snow levels are likely to hover
around the 2500 ft mark, though some guidance shows the potential
for pockets of snow levels down to 1500 ft as a round of moisture
(considerably lighter than what's currently occurring) moves
through the region. This could bring some light snow during the
early morning hours on Monday to some of the passes north of
Grants Pass (Sexton, Canyon Creek, Camas Valley). If these lower
snow levels materialize, it's not out of the question to see some
snow flakes in the West Side Valleys, but at this time, any
accumulations should be minimal if any at all.

The upper trough swings through on Monday, maintaining widespread
showers across the region. Snow levels will hover around 3000 ft
during the day Monday, and with the hit/miss nature of showers,
any winter impacts should be limited to where showers are most
persistent. Showers will taper off late Monday into Tuesday when
we'll catch a break in this active pattern, giving the river
systems time to recede/recover. This break in the weather will be
short lived with another front quickly moving in late Wednesday
(more typical for this time of year) and active weather continuing
through the latter half of the week and into the following
weekend. We'll focus in on details with these upcoming systems
once we're past this current atmospheric river. /BR-y/Spilde

AVIATION...16/06Z TAFs...Widespread showers continue across
northern California and southern Oregon tonight. Flight levels are
generally at VFR or MVFR across the area, with LIFR levels at
Brookings

Rainfall is expected to increase tonight into Sunday morning. With
the amount and consistency expected, flight levels are expected to
be impacted by rainfall through most of the TAF period. Snow showers
will be nearly constant over the Cascades and western Siskiyou
County, possibly obscuring elevated terrain. Widespread light snow
showers may be possible east of the Cascades near the end of this
TAF period.

Winds will be a factor at and above the surface. Low level wind
shear continues for most areas but will start to dissipate from west
to east early Sunday morning. At the surface, gusty winds will
continue to affect elevated terrain. Klamath Falls is expected to
see increasing winds into Sunday afternoon before speeds start to
decrease. -TAD

MARINE...Updated 245 AM Saturday, March 16, 2025...Southerly
winds with gale gusts are expected to continue through the morning
hours for areas mainly south of Cape Blanco, building very steep and
hazardous seas through the day. South winds are expected to shift
west and diminishing from north to south through the late morning
hours. While wind speeds are expected to diminish, seas will remain
very steep and hazardous through this afternoon. Thereafter, steep
seas will continue through Monday afternoon for all waters. Winds
and seas are expected to gradually diminish Monday with below
advisory conditions possible Tuesday. Active weather could return
midweek and bring further unsettled conditions starting Wednesday as
strong southerly winds build steep seas once again.

-Guerrero

&&

.MFR WATCHES/WARNINGS/ADVISORIES...
OR...Flood Watch through this evening for ORZ021>026.

     Winter Storm Warning until 11 PM PDT this evening for
     ORZ027>031.

     High Wind Warning until 5 PM PDT this afternoon for ORZ021-022-
     031.

     Wind Advisory until 8 AM PDT this morning for ORZ023-024-026-029-
     030.

CA...Flood Watch through this evening for CAZ080.

     Winter Storm Warning until 11 PM PDT this evening for CAZ080-082-
     083.

     High Wind Warning until 5 PM PDT this afternoon for CAZ081-084-
     085.

PACIFIC COASTAL WATERS...Gale Warning until 11 AM PDT this morning
     for PZZ356-376.

     Hazardous Seas Warning until 5 PM PDT this afternoon for PZZ350-
     356-370-376.

     Small Craft Advisory from 5 PM this afternoon to 5 PM PDT Monday
     for PZZ350-356-370-376.

&&

Preliminary Local Storm Report
National Weather Service Medford OR
506 AM PDT Sun Mar 16 2025

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

0500 AM     Rain             Gold Beach              42.41N 124.42W
03/16/2025  M4.00 Inch       Curry              OR   Trained Spotter

            24hr total ending at 5am.

&&

Preliminary Local Storm Report
National Weather Service Medford OR
641 AM PDT Sun Mar 16 2025

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

0640 AM     Rain             4 NNE Obrien            42.11N 123.67W
03/16/2025  M1.17 Inch       Josephine          OR   Trained Spotter

            Rainfall since midnight.

&&