Sunday, August19, 2018

Marine Weather and Tides
Lewiston, ID

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Sunrise 5:51AMSunset 7:50PM Sunday August 19, 2018 7:09 AM PDT (14:09 UTC) Moonrise 3:16PMMoonset 12:07AM Illumination 56% Phase: First Quarter Moon; Moon at 8 days in cycle
NOTE: Some of the data on this page has not been verified and should be used with that in mind. It may and occasionally will, be wrong. The tide reports are by xtide and are NOT FOR NAVIGATION.
Marine Forecasts
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7 Day Forecast for Marine Location Near Lewiston, ID
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location: 46.39, -116.98     debug

Area Discussion for - Spokane, WA
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Fxus66 kotx 191127
area forecast discussion
national weather service spokane wa
427 am pdt Sun aug 19 2018

Wildfire smoke will be thick over portions of central and
northeast washington today as north winds transport smoke from the
northern cascades and british columbia into the region. Warm, dry,
and gusty north winds on Monday will raise concerns for the
spread of wildfires. A pattern change during the second half of
the week will bring cooler temperatures and cleaner west winds to
the pacific northwest which should improve air quality.

Strong north to northeast winds Sunday night into Monday...

today: an area of low pressure off the wa coast begins to swing into
oregon while a shortwave digging through central bc approaches
the international border. We will start to see these features
beginning to phase late in the day but overall, weather impacts
through the afternoon will be subtle. The thermally induced
pressure trof at the surface is being suppressed southward and
this has resulted in a stronger push of northerly winds down the
okanogan valley and waterville plateau this morning with gusts of
18-28 mph observed. These winds will weaken later this morning but
look to hold a northerly gradient of 8 to 13 mph throughout the
day. Subtle cooling aloft will also result in a better shot for
cumulus buildups in the northern mountains. Models continue to
show marginal surface based CAPE values supportive for a few weak
showers or t-storm cells but this carries low confidence given
some CIN and lack of support from cam models and sref
probabilities. Temperatures for this afternoon were adjusted
downward based on impacts we observed from the smoke haze Saturday.

Sunday night and Monday: a strong shortwave digging through southern bc
will usher a 1028mb surface high down the continental divide
creating a strong north to northeast pressure gradient and
resultant push of winds. Model trends have been toward stronger
winds in the last 24 hours and forecast winds have been increased
accordingly. This is a favorable pattern for strong north winds
through the okanogan valley, northeast winds down the purcell
trench, and each spilling into the columbia basin from both
directions. Speeds at locations like omak, ephrata, sandpoint, and
across the scablands and open wheat country of the columbia basin
will likely reach sustained speeds of 20-30 mph with stronger
gusts. Gusty winds will also impact the northern mountains between
these favored channels but speeds and gusts will be more chaotic
given different orientations of sheltering. Exposed ridgetops will
be most exposed and as winds swing from north to northeast,
aligned canyons will also experience periods of gusty conditions.

The system will bring a threat for showers and a few thunderstorms but
confidence is not high and models tend to overdue precipitation
with these northeasterly pushes. Nonetheless, given that it is
still august and we are transitioning from a shortwave ridge,
lapse rates will remain quite unstable ahead of the backdoor cold
front and we could see a few areas of showers and thunderstorms
develop in the N idaho panhandle Sunday night into Monday morning
then sagging southward into lower panhandle and extreme SE wa in
the afternoon hours. There is also a ghost of a chance for a few
convective cells to develop along the cascade crest but this looks
closer to the Sunday evening night time-frame vs Monday.

The combination of gusty winds and low humidity values will raise
concern for rapidly spreading wildfires in the okanogan valley
and western columbia basin and fire weather watches have been
issued. Although winds will be just as strong through the purcell
trench of N id and into columbia basin through the west plains,
there is a better chance for cooler temperatures and slightly higher
humidity values keeping readings, thus not falling into "critical
thresholds". Nonetheless, it will be windy.

Smoke and haze will likely remain an issue despite the increasing
winds due to reinforcing smoke from canada. This will continue to
be addressed daily with changes in wildfire behavior, smoke
output, and transport winds shift. Sb
Tuesday: northeast winds should subside through the day Tuesday
as Monday's cold front spreads across the northern plains. The
surface pressure gradient between high pressure in montana and low
pressure over southern oregon will weaken through the day.

Morning winds of 10 to 20 mph in the columbia basin should
diminish to 10 mph or less by late in the day. The mixing behind
Monday's front should disperse some of the smoke in north idaho
and the eastern third of washington. It is unclear how widespread
the improvements will be for okanogan and chelan counties. There
may be enough residual smoke across british columbia and the
northern cascades that mixing from winds on Monday and Tuesday may
not provide enough dispersion for an air mass that is simply
inundated smoke. Anticipating a good deal of smoke across north
central washington, afternoon high temps have been trimmed 3 to 5
degrees below MOS guidance for places like omak, republic,
winthrop, wenatchee, and leavenworth.

Wednesday: the evening models have trended further south with the
passage of a sheared out upper trough on Wednesday. Chances for
showers and thunderstorms have been removed for the northern and
central idaho panhandle as well as eastern washington. Winds are
expected to reverse direction on Wednesday. After Monday and
Tuesday's north or northeast winds, look for a transition to light
south winds during the day Wednesday. Wind speeds probably won't
be strong enough to push smoke out of central and north central
washington, but at least we won't be transporting canadian smoke
into washington as winds become southerly. The transition to west
winds Wednesday night will be good news for the east slopes of the
cascades. West winds will be a "cleaner" wind direction.

Thursday through Saturday: confidence is growing that a
significant pattern change will arrive Thursday with the arrival
of a cool pacific trough. The gfs, ecmwf, canadian, and ensembles
keep this cool trough over the gulf of alaska and british columbia
through the weekend. It looks like the pacific northwest will
experience several days of modest onshore flow... Meaning cooler
temperatures, persistent "clean" west winds, and higher humidity.

At this time, it looks like the trough will remain too far north
for any widespread precipitation in washington or north idaho.

However, some of the big fires in british columbia could get wet
late in the week and into the weekend. At the very least, the
cooler temperatures and higher humidity should slow fire activity
enough to improve our air quality. Gkoch

12z tafs: northerly winds over the region will keep bringing wild
fire smoke into the TAF locations. Predictive skill is low for
where smoke will go and what visibilities will result. The general
thinking is that visibilities will be low this morning, improve
some in the afternoon as inversions lift, then deteriorate Sunday
night as stronger north winds transport smoke toward the taf
sites. A strong northerly wind event is expected to develop after
06z around omak and spread toward the remaining terminals after
12z. Sb

Preliminary point temps pops
Spokane 87 62 84 59 84 59 0 0 10 0 0 0
coeur d'alene 87 58 83 56 84 55 0 10 20 0 0 0
pullman 87 58 85 54 83 54 0 0 20 10 0 0
lewiston 94 64 91 62 89 62 0 10 20 20 10 10
colville 88 55 87 52 88 52 0 0 10 0 0 0
sandpoint 85 53 80 50 83 49 10 10 20 0 0 0
kellogg 87 55 79 52 81 53 10 10 20 0 0 0
moses lake 93 62 92 60 89 57 0 0 0 0 0 0
wenatchee 90 65 91 65 87 64 0 0 0 0 0 0
omak 92 61 91 60 89 60 0 0 0 0 0 0

Otx watches warnings advisories
Id... None.

Wa... None.

Weather Reporting Stations
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Airport Reports
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AirportDistAgeWind ktVisibilitySky/WeatherTempDewPtHumidityPressure
Lewiston, Lewiston-Nez Perce County Airport, ID2 mi73 minSE 310.00 miFair62°F44°F52%1016.6 hPa

Wind History from LWS (wind in knots)
Last 24hrCalmNE3CalmE3NE5NW4N5W5NW3W3W4NW5NW4SE5S5S4SE4SE3CalmCalmCalmCalmSE3E4
1 day agoE7E6E7N7N7NW8N5NW9W11NW10W10NW13NW8SW5S536NW4CalmCalmCalmCalmSE5S4
2 days agoN3S4NE4E6NE5--NW33Calm4CalmS19

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Weather Map and Satellite Images
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GOES Local Image of PacificNorthwest    EDIT
NOTE: East coast views moved to GEOS-16. They are experimental and not well supported by NOAA so they may not be correct so be warned. This change required redoing a large amount of the GOES code. If the image you are expecting is not showing, please let me know. You may need to use the EDIT function to update your location.
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Wind Forecast for Spokane, WA (10,2,3,4)
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Ground Weather Radar Station Spokane, WA
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