[ W WA | SW WA and W OR | SE WA and NE OR | NE WA and N ID ]

Western Washington


499 
FXUS66 KSEW 211101
AFDSEW

Area Forecast Discussion
National Weather Service Seattle WA
300 AM PST Mon Jan 21 2019

.SYNOPSIS...Weak high pressure will produce a break in 
precipitation today into tonight. A pair of frontal systems will 
give rain at times Tuesday into Wednesday. A ridge of high pressure 
aloft will bring about another period of dry weather Thursday into 
early next week.

&&

.SHORT TERM...Weak high pressure is building into the region 
today for a dry day ahead. Surface gradients are light. Combined 
with surface moisture from recent rains, this is producing some 
areas of fog and/or low clouds. This should dissipate by afternoon 
for a partly sunny day for most places. High temperatures today 
should be right around normal for the date. A warm front will lift 
north over the offshore waters tonight. Light rain will develop 
along the coast after midnight tonight then spread into the Puget 
Sound area after daybreak Tuesday. The front falls apart as it moves 
inland so there won't be a lot of QPF with it. A secondary system 
will be quick on its heels Tuesday night into Wednesday for another 
shot of rainfall, rising snow levels, and some breezy to windy 
conditions. The front should be east of the Cascades by Wednesday 
evening with precipitation tapering off ahead of another ridge 
building into the region.   27


&&

.LONG TERM...Models remain in good agreement with an upper ridge 
building into the region Thursday through Saturday for another dry 
period along with near or slightly above normal daytime 
temperatures. By late in the weekend, both the GFS and the Euro 
retrograde the ridge axis offshore. The Euro is more aggressive with 
this idea and allows a weak system to clip the area from the 
northwest on Sunday. This is a relatively new idea in the models 
and, as such, no significant changes were made to the extended 
forecast overnight.   27

&&

.AVIATION...Northwesterly flow aloft through Tuesday morning. 
Upper level ridge shifting east with next front approaching the area 
Tuesday morning. Light flow at the surface becoming southeasterly 
tonight.

Stratus deck with ceilings 3000-4000 feet over much of the interior 
this morning. Patchy fog along the coast and over the Southwest 
Interior with ceilings below 500 feet and visibilities 1-3sm. Lower 
stratus deck, in the 1000-2000 foot range, forming 15z-18z. Both 
stratus decks scattering out in the afternoon with just high level 
clouds this evening. Increasing mid level deck after 05z with next 
front approaching. 

KSEA...Confidence not real high in the TAF this morning. With the 
light flow in the lower levels potential for a lower stratus deck 
near 1000 feet to form under current stratus deck near 3000 feet. 
Even if lower stratus deck does not form 3000 foot layer hanging 
over the terminal into the early afternoon hours. A few hours of 
just some high clouds before clouds increase again late tonight with 
next system approaching. Expect VFR ceilings to continue through 
Tuesday morning. Southerly winds 4 to 8 knots into Tuesday morning. 
Felton

&&

.MARINE...Light winds will result in relatively quiet conditions 
across area waters today. A series of weak frontal systems will 
affect the region tonight through Wednesday, bringing at least 
advisory-level winds to most area waters. There is a slight chance 
that winds could touch gale force over the northern coastal waters 
just west of Makah Bay between 09-18z Tuesday. However, consensus 
places winds just below that threshold so will keep an SCA there for 
now (as well as most other inner and outer coast waters) and let the 
next shift take another look. Once winds diminish Wednesday, 
relatively quiescent conditions appear likely through late this 
week, and potentially into the weekend. 

The other concern is the ongoing King Tide cycle. A Coastal Flood 
Advisory is in effect around high tide for the next two afternoons 
for the coastline of Grays Harbor County where minor tidal overflow 
will be possible. On Wednesday, concerns for minor tidal overflow 
shift to the inner coast shorelines. We will be monitoring that 
potential.
-Wolcott-

&&

.HYDROLOGY...The idea that a couple of weak fronts would just brush 
the area Tuesday and Wednesday is trending toward wetter solutions. 
Considering how easily the Skokomish river made it up to flood stage 
with this past front, I think now that the river forecast bears 
watching for the middle of the week. For now, I just have the river 
starting upward again on Tuesday and do not have a forecast for 
Wednesday--but that's the day to watch of the models keep up this 
trend. Elsewhere, river flooding is not expected over the next 7 
days.

&&

.SEW WATCHES/WARNINGS/ADVISORIES...
WA...Coastal Flood Advisory from 11 AM this morning to 3 PM PST this 
     afternoon for Central Coast.

     Coastal Flood Advisory from noon to 4 PM PST Tuesday for Central 
     Coast.

PZ...Small Craft Advisory from 8 PM this evening to 10 AM PST 
     Wednesday for Coastal Waters From Cape Flattery To James 
     Island 10 To 60 Nm-Coastal Waters From Cape Flattery To 
     James Island Out 10 Nm-Coastal Waters From James Island To 
     Point Grenville 10 To 60 Nm-Coastal Waters From James 
     Island To Point Grenville Out 10 Nm-Coastal Waters From 
     Point Grenville To Cape Shoalwater 10 To 60 Nm-Coastal 
     Waters From Point Grenville To Cape Shoalwater Out 10 Nm.

     Small Craft Advisory from midnight tonight to 7 AM PST Wednesday 
     for Admiralty Inlet-East Entrance U.S. Waters Strait Of 
     Juan De Fuca-Northern Inland Waters Including The San Juan 
     Islands-Puget Sound and Hood Canal-West Entrance U.S. 
     Waters Strait Of Juan De Fuca.

&&

$$

www.weather.gov/seattle

[ W WA | SW WA and W OR | SE WA and NE OR | NE WA and N ID ]

Southwestern Washington and Western Oregon


684 
FXUS66 KPQR 211107
AFDPQR

Area Forecast Discussion
National Weather Service Portland OR 
255 AM PST Mon Jan 21 2019


.SYNOPSIS...Several storm systems traversing the region through the
middle of the week will bring periods of valley rain and mountain
snow before high pressure brings drier weather late in the week and
next weekend. 


&&


.SHORT TERM...Today through Thursday...Water vapor satellite imagery
early this morning reveals a large shortwave trough centered over the
Great Basin. A couple embedded vort maxes are apparent on satellite
imagery along the backside of the trough. The first is located near
the Oregon/California border. This system is slowly dropping
south-southeastward and will continue to result in decreasing shower
chances from north to south early this morning. Areas that experience
any breaks in cloud cover will develop fog quickly this morning given
the current low dewpoint depressions and light winds found across the
region. The second vort max is weaker and located off the Washington
coast. This system will drop southeastward across the area towards
midday and could help initiate a few light showers this afternoon,
but any rain should be spotty in nature. Shortwave ridging centered
more squarely in the eastern Pacific will then push eastward towards
the region and result in a temporary dry period for most of tonight. 

The aforementioned shortwave ridging will be initially low in
amplitude early this week. This will allow a series of weak fronts to
push into the Pacific Northwest during the first half of the week.
The first will come in the form of a warm front. This will spread
rain into our northwestern zones by daybreak on Tuesday. While our
northern zones will almost certainly see light rain for much of
Tuesday, whether it rains enough to wet the pavement around Eugene
and across much of southern Lane County looks like a flip of a coin
at this point. Either way, snow levels will initially start out near
2000 feet Tuesday morning before rising up towards 5000 feet Tuesday 
night. Overall, QPF should be light enough to prevent a need for 
Winter Wx headlines across the Cascades, though. A trailing cold 
front will then drop southward across the area late Tuesday night 
and early Wednesday. A frontal rain band may bring a couple hours of 
moderate rain as it drops southward, but few impacts are anticipated.
Models then agree shortwave ridging will build farther northward
Wednesday night into Thursday. This should bring a gradual end to any
rain chances across the area and there may be enough breaks in the
clouds to allow areas of valley fog to develop. /Neuman
   

.LONG TERM...Thursday night through Monday...Operational models and
most ensembles continue to suggest shortwave ridging will more or
less remain over the Pacific Northwest for the entire extended
forecast period. This should result in conditions remaining dry
across the forecast area during this time. Areas of valley fog should
develop each night and linger into each morning before giving way to
afternoon sunshine and near average temperatures for the date. There
are some hints that a shortwave trough dropping down the backside of 
the upper level ridge could dive west of the Continental Divide. This 
scenario would likely help to enhance east winds near the mouth of 
the Columbia River Gorge Sunday night into Monday. It should be 
noted that there may be enough of a north to south pressure gradient 
Thursday and again on Sunday to prevent the need to issue Air 
Stagnation Advisories later this week and over the weekend. /Neuman 


&&


.AVIATION...A mixture of IFR, MVFR and VFR conditions across the
region this morning with fog and low clouds settling in. With 
ample low level moisture and light winds, expect dense fog to 
become more widespread this morning with most inland terminals 
deteriorating to IFR conditions. The fog and stratus will 
eventually lift to a MVFR deck during the late morning and VFR 
later this afternoon as drier northerly flow arrives. At the 
coast, primarily MVFR conditions through the morning hours, then 
becoming VFR by midday or early afternoon. 

KPDX AND APPROACHES...IFR with fog and stratus through 16-18z,
then slowly lifting to MVFR conditions by late morning. VFR by
21-22z as drier northerly flow establishes. 


&&


.MARINE...Northerly winds over the waters today as the upper
level low to our south moves inland. Winds will be in the high 
teens to around 20 kts today. May see some occasional gusts poke 
above 20 kt in the far southern waters, but think they will be 
rather isolated. 

The next significant uptick in winds will be Monday night 
through Wednesday morning with solid 25-30 kts wind gusts. Opted
to issue a small craft advisory for Monday night through early 
Wednesday. These winds will ease later Wednesday, then expect 
fairly benign winter conditions for the rest of the week 
thereafter. 

Seas will remain 7-9 ft through Monday night, then rise to around
10 to 13 ft Tuesday morning through Wednesday. Seas fall back
below 10 ft on Thursday.  /tw


&&


.PQR WATCHES/WARNINGS/ADVISORIES...
OR...Coastal Flood Advisory from noon today to 3 PM PST this 
     afternoon for North Oregon Coast.

     Coastal Flood Advisory from noon to 4 PM PST Tuesday for North 
     Oregon Coast.

WA...Coastal Flood Advisory from noon today to 3 PM PST this 
     afternoon for South Washington Coast.

     Coastal Flood Advisory from noon to 4 PM PST Tuesday for South 
     Washington Coast.

PZ...Small Craft Advisory for winds from 10 PM this evening to 4 AM 
     PST Wednesday for Coastal Waters from Cape Shoalwater WA 
     to Cascade Head OR out 60 NM.

     Small Craft Advisory for winds from 4 AM Tuesday to 4 AM PST 
     Wednesday for Coastal Waters from Cascade Head OR to 
     Florence OR out 60 NM.

     Small Craft Advisory for Rough Columbia River Bar from 3 PM 
     this afternoon to 7 PM PST this evening.

&&


$$

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This discussion is for Northwest Oregon and Southwest Washington 
from the Cascade crest to 60 nautical miles offshore. This area is 
commonly referred to as the forecast area.

[ W WA | SW WA and W OR | SE WA and NE OR | NE WA and N ID ]

Southeastern Washington and Northeastern Oregon


448 
FXUS66 KPDT 211019
AFDPDT

Area Forecast Discussion
National Weather Service Pendleton OR
220 AM PST Mon Jan 21 2019

.SHORT TERM...Today through Wednesday...A weather system that 
brought rain and higher mountain snow to the forecast area on Sunday 
will continue to move to the east and out of the area today. 
However, there are still some light upslope rain and snow showers 
over the northern Blue Mountains and foothills, which will end in 
the next hour or two. The precipitation type was snow at the KPDT 
airport last evening, but it has warmed up a degree or two and now 
the precipitation is rain. At Meacham, light snow is falling with a 
temperature of 29 degrees. Elsewhere across the CWA the atmosphere 
is drying out and is essentially precipitation free. A ridge of high 
pressure with a northerly flow will develop over the forecast area 
today and tonight and will bring drier weather. There will be patchy 
fog over much of the CWA at night and during the early morning. 
Temperatures will be near freezing so it will be a mixture of fog 
and freezing fog, depending on where colder air is trapped or not 
trapped...otherwise skies will be mostly fair. The next weather 
system will move into the region on Tuesday night into Wednesday 
bringing more lower elevation rain and higher elevation snow to the 
forecast area. There could be a need for winter weather highlights 
for the mountains, but there is too much uncertainty this early on 
to be sure how much snow will fall, if it will be enough to reach 
the criteria for an advisory. Therefore, will not issue one on this 
shift. Winds will be light through Tuesday. After that southwest 
pressure gradients will tighten up and it will become breezy to 
windy over most of the CWA for Wednesday. Temperatures will be a 
little above normal, especially on Tuesday and Wednesday. 88

.LONG TERM...Wednesday night through Sunday. Some mountain showers 
will linger over the area Wednesday night in northwest flow.  A 
ridge of high pressure will be building over the area through the 
rest of the week and should continue through the weekend.  Models 
are all a little different with position and strength of the ridge 
and when some moisture may work through, but overall idea will be 
for dry conditions.  As the ridge persists, there will be fog and 
low clouds develop in the Columbia Basin and spread to surrounding 
valleys. Temperatures should be near to above normal, especially in 
the mountains, but may need to be adjusted in the valleys as fog and 
low cloud areas are better defined. 93 

&&

.AVIATION...12Z Tafs.  Patchy fog will continue to drift around the 
Columbia Basin, but with the northwest flow, most likely to persist 
along the foothills, ALW and PDT with IFR and LIFR cigs and vsby 
through at least 18z. PSC and YKM are expected to see improving 
conditions after 15z. DLS/RDM/BDN will see IFR cigs improving by 18z 
as well.  Winds will generally be under 12 kts and patchy fog and 
low clouds are likely to develop again late tonight.  93  


&&

.PRELIMINARY POINT TEMPS/POPS...
PDT  38  28  41  37 /  10   0  30  50 
ALW  40  31  43  40 /  10   0  40  60 
PSC  43  32  43  40 /   0   0  30  40 
YKM  41  27  40  34 /   0   0  30  40 
HRI  43  31  44  38 /   0   0  30  50 
ELN  38  26  37  32 /   0   0  30  40 
RDM  39  24  42  32 /  10   0  30  30 
LGD  37  23  39  34 /  20   0  30  60 
GCD  38  24  41  34 /  20  10  30  40 
DLS  43  32  42  38 /   0   0  50  60 

&&

.PDT WATCHES/WARNINGS/ADVISORIES...
OR...None.
WA...None.
&&

$$

88/93/93

[ W WA | SW WA and W OR | SE WA and NE OR | NE WA and N ID ]

Northeastern Washington and Northern Idaho


695 
FXUS66 KOTX 211207
AFDOTX

Area Forecast Discussion
National Weather Service Spokane WA
407 AM PST Mon Jan 21 2019

.SYNOPSIS...
A few snow showers will persist across north Idaho, otherwise dry 
weather is expected across the region today.  The active pattern 
will continue with the potential of lowland snow Tuesday night into 
Wednesday. Expect dry weather with seasonable temperatures late this 
week. 

&&

.DISCUSSION...

...Moderate to heavy snow possible in northeast WA and the ID
Panhandle with travel impacts to the Wednesday morning commute...

Today through Tuesday: Yesterday's shortwave trough has shifted east 
into Montana early this morning, with an upper ridge over the 
eastern Pacific building along the West Coast. Moist northwesterly 
flow persists north Idaho, with orographic lift producing a few snow 
showers. The potential for these showers will continue through the 
day, with little to no additional accumulation expected. Elsewhere, 
drier northerly flow has developed across northern WA and far 
northern ID, inhibiting the formation of freezing fog in those 
locations. Farther south, areas of freezing fog have developed, with 
quarter-mile visibilities noted at Pullman Airport at this hour. 
These areas of fog may spread as far north as Spokane-CdA-Sandpoint 
this morning.

Fog and low clouds are expected to be more widespread Monday night 
into Tuesday morning as the upper ridge flattens, and as boundary 
layer winds become more southwesterly. The next low pressure system 
then begins to move into the region Tuesday, with the possibility of 
snow moving east of the Cascades during the afternoon hours.
Dang

Tuesday night through Thursday: Models are coming into better
agreement with the strength of a warm front and subsequent
precipitation amounts for Tuesday night into Wednesday with the 
GFS and NAM trending toward the more consistent wetter ECMWF. The
forecast has been trended this way to reflect the precip amounts 
exhibited off of the 00Z ECMWF solution, but still isn't quite as 
wet. The main reason for this is that ensemble guidance such as 
the GEFS and SREF still shows enough evidence that the ECMWF may 
still be on the wet side, at least across the basin an into north-
central and northeast WA. Precip type will be a challenge across 
the basin and across the Highway 2 corridor and into the valleys adjacent
to the basin. The reason for this is that warmer air moving in 
will result in a precip type change from snow to rain. How that 
transition transpires will greatly influence snow amounts. 

Confidence in snow amounts is highest across the northern 
mountains and valleys and into the central to northern ID 
Panhandle. Advisory snow amounts of 2 to 4 inches from the 
Okanogan Highlands to the Northern Panhandle. Around 2 to 3 inches
is expected for the Spokane Area to the northern portion of the 
Palouse, but these amounts hold only moderate confidence at best 
at this point. The Coeur d'Alene Area looks to get closer to 3 to 
5 inches with around 5 inches possible up the Silver Valley. Heavy
snow is anticipated for Lookout Pass with winter travel likely 
along I-90 from at least Spokane to the Montana border. I wouldn't
be surprised if we will need a Winter Storm Warning for the 
Central Panhandle Mtns, but confidence isn't high enough for a 
watch or warning at this time. Snow is likely to be heavy and wet 
especially around the Spokane Area and on the Palouse. Expect 
slick travel due to slushy snow accumulations during the Wednesday
morning commute.

Winds are also expected to become breezy through the morning 
Wednesday and lasting into the afternoon over the basin and into 
the Spokane Area and Palouse. Wind gusts up to around 30 mph will 
be possible. Blowing snow is not expected to be a concern though 
considering how wet the snow is expected to be. Precip will 
decrease into Wednesday night with Thursday being mostly dry 
except for possibly some lingering showers in the ID Panhandle. 
/SVH

Friday through Monday: Forecast confidence is high that a strong 
upper ridge will build over the eastern Pacific in this timeframe. 
Medium range models hint at the possibility of a northerly shortwave 
that could bring a few snow showers this weekend or early next week. 
Most of the region should remain dry however. Some low clouds or fog 
are likely to develop under the ridge.
Dang


&&

.AVIATION...
12z TAFs: Dry weather across TAF sites in the wake of yesterday's
weather system. Low clouds and patchy fog will bring periods of
MVFR/IFR conditions to KGEG-KSFF-KCOE-KPUW-KEAT this morning, with
VFR conditions at KLWS-KMWH. Some improvement in conditions is 
expected after noon but a reversal to southerly winds will likely
spread persistent low clouds and fog across much of the region
(with the exception of KLWS and KEAT) after 03z tonight. 
Dang

&&

.PRELIMINARY POINT TEMPS/POPS...
Spokane        34  25  35  32  40  27 /   0   0  30  80  40   0 
Coeur d'Alene  33  24  35  31  39  27 /   0   0  40  90  70   0 
Pullman        32  24  35  32  42  30 /   0   0  30  80  70  10 
Lewiston       40  28  41  37  48  35 /   0   0  20  70  50  20 
Colville       39  22  37  27  42  23 /   0   0  30  80  40   0 
Sandpoint      34  24  33  31  38  28 /   0  10  70  90  80  10 
Kellogg        32  23  33  30  39  30 /  20  10  50  90  90  20 
Moses Lake     40  27  38  32  47  29 /   0   0  30  50  10   0 
Wenatchee      37  26  35  32  44  31 /   0   0  30  50  30   0 
Omak           37  24  34  30  41  27 /   0   0  30  50  20   0 

&&

.OTX WATCHES/WARNINGS/ADVISORIES...
ID...Winter Weather Advisory until 7 AM PST this morning above 3000 
     feet for Central Panhandle Mountains.

WA...None.

&&

$$

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