534
FXUS66 KMFR 300315
AFDMFR

Area Forecast Discussion
National Weather Service Medford OR
815 PM PDT Wed May 29 2024

.DISCUSSION...

Pretty quiet weather persists this evening with no thunderstorms
around like the last few evenings. There are some prescribed
burns which are putting some smoke out east of the Cascades.
Therefore, we added patchy smoke wording in northern Lake and
Klamath Counties due to the smoke on satellite. Very few people
should be impacted from this smoke. Otherwise, temperatures will
be warm enough tonight to avoid the threat from frost and freeze
west of the Cascades. East of the Cascades, most areas will see
frost with some spots dropping below freezing, like Chemult.

Read the discussion for more information on the wet period next
week.

&&

.AVIATION...30/00Z TAFs...Along the coast VFR conditions continue
this evening and overnight with a less than 10% probability of
ceilings falling below 3,000 feet. Northerly winds will pick up
again tomorrow. There is a 60-70% probability for winds to gust to
22 knots between 3 PM-6 PM Thursday.

Inland, west of the Cascades, ceilings are expected to remain VFR
through the TAF period. Winds will be slightly breezy Thursday
afternoon, and some locations could see wind gusts reaching 20-25
knots at most.

East of the Cascades, VFR conditions will continue through the TAF
period. Moderate winds with peak gusts nearing 25 kts at Klamath
Falls this afternoon will wind down this evening.
-Miles/Hermansen

&&

.MARINE...Updated 800 PM Wednesday, May 29, 2024...A thermal trough
is developing this evening and tonight, resulting in increasing
north winds that will reach Small Craft Advisory conditions for all
south of Bandon. The thermal trough will strengthen further, peaking
Thursday evening, and persisting through at least Friday evening;
resulting in gale force winds for most areas south of Cape Blanco
and for isolated instances across the waters between Bandon and Cape
Blanco. Meanwhile small craft conditions will expand north over the
rest of the waters that will last into at least Friday evening.

The thermal trough will weaken overnight Friday into Saturday and
north winds will diminish as an upper trough approaches. Calmer seas
are expected by the weekend and into early next week after the wind
waves have diminished.

-Miles/Hermansen

&&

.PREV DISCUSSION... /Issued 216 PM PDT Wed May 29 2024/

SHORT TERM...Rest of today through late Thursday night...At the
large scale, a midlevel trough is gradually moving off to the
east today as a low amplitude ridge builds in behind it. At the
moment, this has resulted in NW flow aloft in the local area as
we`re sandwiched between the two regimes, which has resulted in
cooler (relatively) temperatures and a little bit of cloud cover.
Per satellite imagery, cirrus is moving southeast across the
region, while some scattered cumulus is present in Douglas/Coos
and NW Curry/Josephine/Jackson counties this afternoon.

Overnight, temperatures will drop to levels similar to last
night/early this morning, if not a tad lower due to increased
radiational cooling with relatively less cloud cover. Tomorrow
will then see clearer, warmer weather with afternoon temperatures
in the high 70s to low 80s (western valleys and the Brookings
area), low to mid 70s (eastern valleys), and low to mid 60s
(mountains, remainder of the coast). We`ll have some seasonable
afternoon/evening breezes and dry weather through the entire
region. A little bit of cloud cover is expected in the morning
(stratus in Coos into inland Douglas counties as well as some more
upper level cirrus) that will clear over the course of the day.
Overnight temperatures will then be average for this time of
year, a couple of degrees warmer than tonight`s temperatures.

Finally, this will be my last AFD here at Medford, as this
forecaster is transferring to southern CA (please keep your boos
and hisses for after the AFD, please). Not very interesting
weather as a send off, but lovely conditions to move in, at least.
Thanks for everything Medford, I`ll miss you. -CSP

LONG TERM (Friday through Tuesday)...

Overview:

The long term will be noted by slightly above normal temperatures
and generally dry conditions until Sunday night/Monday. The system
coming into the region end of the weekend/early next week will be
moisture rich but lacking some variables which could make this more
impactful. We will talk about this further below, but at this time
it does appear impacts will be limited at best. The coast could see
rainfall amounts approaching 2 inches in some isolated areas that
could cause minor nuisance issues. Interestingly enough, the
rainfall amounts have gone up each forecast over the last 24 hours,
so we could see changes to those amounts near the coast. Otherwise,
little to no impacts are expected inland as amounts drop off
significantly, and we are not expecting thunderstorms at this time.
Lastly, we will have several breezy days in the forecast, and Monday
looks to be the "windiest" of the days at this time (behind the cold
front), especially the eastside across our typical windy spots
where a wind advisory may come to fruition.

Further Details:

By Friday, it looks like the upper levels might resemble a general
zonal (west to east) type of flow downstream of the next trough.
There is a small discernible piece of energy embedded in this flow,
so expecting clouds to increase in coverage Friday and more so on
Saturday. By Sunday, appreciable upper level moisture will be
present with forecast soundings suggesting PWATs could be around
1.50" at KOTH with a very deep saturated column. This moisture will
coincide with a strong H3 jet nosing into the area. The left exit
region of the upper jet, and the 500mb vorticity max are both a
little farther north than one would like to see for high rainfall
rates. We will have to watch these variables because they will
coincide with the highest rainfall amounts if phased together
correctly, and at this time it does look like those amounts may be
highest just to our north along the central to northern Oregon
coast. Along our coastal waters of southern Oregon, the probability
for rainfall amounts to be 0.50" or more in 12 hours is around 30-40
percent ending Monday morning. This is of course a broad brush with
coarse resolution given this is Day 5/6. Total forecast rainfall
amounts currently put much of Curry County at 1.00-1.50" of rainfall
over 36 hours from early Sunday afternoon through Monday night. The
highest rates could be between Sunday night and Monday morning, so
the Monday morning commute may have nuisance issues with rainfall.
All that said, its the coast and it can inherently take a lot of
rainfall, so at this time we are expecting very limited impacts, but
it may not be a bad idea to plan for longer commutes on Monday
morning if you live along/near the coast.

-Guerrero

&&

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

PACIFIC COASTAL WATERS...Small Craft Advisory until 5 AM PDT Thursday
     for PZZ350-356-370-376.

Gale Warning from 5 AM Thursday to 11 PM PDT Friday for PZZ356-
     376.

&&

$$