Hazardous Seas Warning 48, NWS Medford, OR

Area Forecast Discussion
National Weather Service Medford OR
846 AM PDT THU JUN 23 2016

.DISCUSSION...No updates planned this morning. A weak cold front
is edging toward the coast this morning. We've only seen one site
measure any rain (near Coos Bay), but plenty of clouds have
streamed onshore ahead of the front. The front will move across
the west side today and produce a few showers mainly at the coast
and in the Umpqua Basin. We can't rule out a shower elsewhere, but
it is unlikely. East of the Cascades, we'll see gusty west-
southwest winds in advance of the front this afternoon, then the
front moves through this evening. We can't rule out a shower with
the front over there either, but the odds are against it. All
areas will be cooler than yesterday but to a lesser degree over in
Modoc and Lake Counties where the front will arrive later. -Wright

&&

.PREV DISCUSSION... /Issued 442 AM PDT THU JUN 23 2016/

DISCUSSION...An upper low well to the north will sink southward
and becoming centered off the Washington and Northern Oregon coast
today. Meanwhile, a front will gradually push into the coast this
morning and inland during the day. This pattern will bring cooler
temperatures, breezy west winds, and showers. The low will shift
inland tonight but remain centered north of the area, then will
shift eastward on Friday. A warming trend follows Saturday into
Sunday as an upper level ridge builds over the area.

Light showers are expected to move into coastal areas this morning
then spread inland into western portions of the area this
afternoon, mainly the Umpqua Valley and Southern Oregon Cascades.
As the upper low moves inland centered just to the north, expect
continued showers this evening and into tonight for these areas.
Some light showers may also spread into the Rogue, Applegate, and
Illinois Valleys.

East of the Cascades and in Northern California expect mainly dry
weather today and tonight. Breezy west to northwest winds are
expected though, especially from the Cascades eastward late this
afternoon and this evening.

Shower activity will taper off late tonight into Friday morning as
the low shifts east. On Friday expect continued cooler than normal
temperatures.

On Saturday, daytime temperatures will warm 10 to 12 degrees with
highs in the upper 80s to low 90s for many west side inland
valleys and into the 80s for eastern valleys. A surface thermal
trough is expected to bring offshore easterly flow to the coastal
mountains and may allow a mild warming effect in the Brookings
area. The ridge pattern remains over the region Sunday with a
shortwave trough moving into the ridge Sunday night and Monday.
There are some indications that a slight chance for showers or
thunderstorms is possible near the Southern Oregon Cascades Monday
afternoon and evening. Will need to monitor this with future model
runs.

In the extended, models continue to show a ridge dominating the
West with shortwaves moving into area Tuesday through late next
week. This will result in very warm temperatures with highs around
10 to 15 degrees above normal. With models showing shortwaves to
move into the area from the west with an increase in mid level
moisture and instability, will need to monitor for the possibility
of isolated thunderstorms. Current models are showing low
confidence on when and where any convective activity will develop
next week. Have kept mention of thunderstorms out of the forecast.
/CC

AVIATION...For the 23/12Z TAF cycle...MVFR ceilings have
moved into the coast north of Cape Blanco early this morning in
response to a cold front pushing in from the Pacific. Expect these
ceilings and some light rain to spread inland into the Umpqua Valley
near Roseburg later this morning or this afternoon. Terrain
along and west of the Cascades will be obscured at times. VFR
will prevail to the south of the Umpqua Divide and also east of
the Cascades. Gusty northwest to west winds will develop this
afternoon and evening, especially over the East Side. -Spilde

MARINE...Updated 230 AM PDT Thu 23 June 2016...A weak cold
front will move onshore today. Light to moderate southwest winds
this morning will shift to the northwest this afternoon and evening.
Seas will remain relatively low. A thermal trough will redevelop
Friday into the weekend...bringing a return of strong north winds
and choppy seas. -Spilde

FIRE WEATHER...Updated 230 AM PDT Thu 23 June 2016...The main short
term concern will be gusty southwest to west winds this afternoon
and evening...especially east of the Cascades. The strongest winds
will be over the higher terrain east of the Cascades with frequent
30 to 35 mph gusts...perhaps even up to 40 mph in the windier spots.
Despite the expected gusty winds this afternoon and evening, we are
also expecting several degrees of cooling along with an increase in
relative humidity as a cold front passes through. No precipitation
is expected east of the Cascades, but some light rain will likely
occur today along the coast, in the Umpqua Valley and the Cascades
north of about Highway 140.

An upper low will swing north of the area Friday morning, then move
east Friday afternoon. The models show a relatively strong west to
northwest flow at 700 mb for this time of the year as the upper
trough moves through. Thus, there is concern for gusty west to
northwest winds to remain an issue Friday afternoon east of the
Cascades. Temperatures should remain cool and relative humidities
higher on Friday and and it will be dry.

Dry and much warmer weather is on the way starting Saturday and
could last into at least the middle of next week. While we are not
expecting a full blown heat wave, max temperatures are expected to
average 10-15 degrees above normal. A thermal trough will redevelop
over this weekend bringing further drying above the mid slopes along
with mild overnight temperatures. -Spilde

&&

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

CA...None.

Pacific Coastal Waters...None.

TRW/TRW/TRW