Forecast Discussions mentioning any of "ACARS" "MDCRS" "AIRCRAFT" "TAMDAR" "AMDAR" "WVSS" received at GSD on 10/27/19

Area Forecast Discussion

National Weather Service Medford OR

 804 PM PDT Sat Oct 26 2019

.DISCUSSION...An update was already sent earlier this evening, and
this was to add showers to the Cascades north of Crater Lake and
along the higher terrain of Lake county. A strong, but mostly dry
trough is moving south across the forecast area and there are a
few showers associated with it. These showers aren`t expected to
produce much, if any, precipitation as this trough is running
into a fairly dry air mass.

The more impactful aspects of this trough are the strong east to
northeast winds expected overnight tonight and cold morning lows
expected through Wednesday morning. A wind advisory remains in
effect for the higher terrain above 2000 feet of Curry and
Josephine counties where gusts to 45 mph are likely. Winds will
diminish Sunday morning and conditions will remain dry through
much of the forecast. Dewpoints will gradually lower Sunday into
Wednesday and this will allow for some cold nights through the
first half of the week. West of the Cascades, guidance indicates
low temperatures in the upper 20s to low 30s, including in the
Umpqua Basin where freezing temperatures have not yet occurred
this season. Even along the coast north of Cape Blanco,
temperatures will be favorable for frost conditions and may even
reach freezing Tuesday and Wednesday mornings. East of the
Cascades, temperatures will be even colder, with low 20s to low
teens likely Monday and Tuesday mornings and single digits
possible for the colder areas. Some locations could be flirting
with record lows during this time. Those in these areas should
take precautions to protect your pets and property from these very
cold temperatures. /BR-y

&&

.AVIATION...For the 27/00Z TAFs...VFR conditions under clear skies
will prevail through Sunday.

The primary concern will be gusty north to northeast winds at all
TAF sites this evening, and possibly into the overnight hours at
Klamath Falls. Peak wind gusts this evening at North Bend,
Roseburg and Medford will be mostly in the 20-25 kt range. These
should subside later this evening.

At Klamath Falls, gusts of 25-30 kt are expected tonight into
Sunday. Guidance is showing ~35 kt of wind only 1000-2000 ft
above the surface, so it wouldn`t take much to have gusts reach
35 kt, but minimal downward transport during the overnight period
should keep winds a bit lower. Even so, the combination of wind
speed and wind direction shift could be enough to cause a
change in flight conditions for approaching and departing general
aviation aircraft this evening. -Spilde

&&

.MARINE...Updated 700 PM PDT Saturday 26 October 2019...A strong
thermal trough will bring continued north gales with steep to very
steep seas tonight into Sunday morning. Gales are now expected to
remain mainly south of Gold Beach and beyond 10 nm from shore. The
thermal trough that is responsible for these strong winds will
weaken a bit Sunday and Monday, and winds will diminish as a result.
Seas, however, will remain hazardous and elevated due to fresh swell
through at least Monday. Then seas will subside some, but will
likely remain hazardous to small craft due to residual fresh swell
and a long period northwest swell of 4 to 5 feet moving into the
waters. Conditions improve further Wednesday afternoon and should
remain below advisory criteria through at least Saturday. /BR-y

&&

.PREV DISCUSSION... /Issued 531 PM PDT Sat Oct 26 2019/

SHORT TERM...Tonight through Tue 29 Oct 2019...

Clear, sunny skies for most all areas not in Douglas
County. A visibly boring pattern, but one with some challenges.
Starting with, strong winds tonight into Sunday morning. Winds will
be strongest along elevated areas above 2000 ft. Our main concern
here is that these winds may cause campfires to get out of control;
more information on this can be gleaned in the fire weather portion.
The easterly wind pattern stays around into the extended but tonight
seems to be its peak. Some gusty winds may mix into the valleys
starting this afternoon, see the aviation discussion for the main
impacts this will cause. Next, is that the invading air mass brings
with it cold temperatures that east of the Cascades should be well
below freezing. West of the Cascades, the main concern is freezing
temps in western Douglas and Coos County, where updates to the
forecast lowered expected temperatures by a few degrees. Current
expectations are for any freezing temperatures not to last long and
be isolated to south eastern Coos County. Therefore, have gone with
frost rather than freeze on these nights. Also, a thermal trough at
the coast will begin to weaken as the day goes on from the ridge
getting pushed south as a low rides over it out of British Columbia
into Montana; see the marine discussion for more. Otherwise, it`s
what would be expected under high pressure, clear skies, and
continued northeast winds at the lower levels. The upper ridge`s
strength begins to waver going into the extended. -Miles

LONG TERM...Wed 30 Oct through Sat 02 Nov 2019.

The extended period will start off Wednesday morning with a strong
long wave ridge out around 140W and a deep trough over the
intermountain states. The Medford CWA will be under dry northerly
flow with low level northeasterly flow.  This will make for
continued clear skies with cold mornings and mild afternoons.

The ridge will drift slowly west and amplify Wednesday into Friday
afternoon, by which time it will have moved to 130W. Flow aloft over
the Medford CWA will gradually become more northwesterly. Low level
flow will become onshore at some point during this interval,
allowing the marine layer to return to the coastal waters and coast.
The remainder of the area will remain mostly clear, but temperatures
will warm a bit Wednesday into Thursday, then cool a few degrees
Friday as the ridge begins to break down. The breakdown and cooling
will continue through Saturday, but it will remain dry through the
weekend and beyond. -Stockton

FIRE WEATHER...Updated 200 PM PDT Saturday 26 October 2019...
A cold upper trough is now digging into the area and a strong
thermal trough is developing near the coast. The upper trough
will bring in cooler air with the strongest push of cold air east
of the Cascades. The thermal trough will bring strong east to
northeast winds to the area Saturday into Sunday. Winds will peak
Saturday evening through Sunday morning with gusts of 30 to 45 mph
over the exposed ridges of the Coast Range, Siskiyou Mountains,
Southern Oregon Cascades and mountains in Siskiyou County.
Overnight recoveries Saturday night will be generally moderate
with some locally poor recoveries possible for the mountains in
Curry County. Winds will gradually lower Sunday afternoon through
Monday morning. Daytime humidities on Sunday will be very dry
across inland areas with humidities in the lower teens to 20
percent range, except for higher humidities in the Umpqua Basin.
Although winds will trend lower, overnight humidities will lower
Sunday night with poor to moderate RH recoveries expected over the
mid-upper slopes/ridges.

Next week, the dry pattern will continue as high pressure centered
offshore nudges into the area. Temperatures will trend slightly
warmer Monday through Friday with continued light to moderate east
winds over the ridges with moderate to locally poor humidity
recoveries. Daytime humidities will also be quite low, except for
locally higher values in the Umpqua Basin. -Stockton

&&

.MFR WATCHES/WARNINGS/ADVISORIES...
OR...Beach Hazards Statement from late Sunday night through Monday
     evening for ORZ021-022.
     Wind Advisory until 11 AM PDT Sunday for ORZ021>024-028.

CA...None.

Pacific Coastal Waters...Beach Hazards Statement from late Sunday night through Monday
     evening for PZZ350-356.
     Small Craft Advisory until 11 PM PDT Monday for PZZ350-356-370.
     Hazardous Seas Warning until 11 PM PDT Monday for PZZ356-376.
     Hazardous Seas Warning until 11 AM PDT Sunday for PZZ350-370.
     Small Craft Advisory from 11 AM Sunday to 11 PM PDT Monday for
     PZZ376.
     Gale Warning until 11 AM PDT Sunday for PZZ376.

$$

MNF/MAS/MB