Scientific Forecaster Discussion
Area forecast discussion
National Weather Service Spokane Washington
755 PM PST Monday Jan 26 2015
areas of low clouds and fog will persist across portions of
inland northwest as high pressure remains strong. A couple of
weak storm systems will affect the area Tuesday through Wednesday
night and bring a small chance of showers and cooler temperatures
to the region. A ridge of high pressure will then rebound late in
the week for drier weather and more fog before breaking down next
evening update to increase coverage of dense fog and issue dense
fog advisory. Dense fog never really cleared out of the north
Idaho Panhandle this afternoon with the worst visibilities noted
along the us95 corridor between Bonners Ferry and Athol. Cams this
evening showed ceilings with this activity lowering toward the
surface just prior to sunset. Further west into Washington,
areas of dense fog are producing low visibilities across many
northeastern sections of the state including Colville, Laurier,
Kettle Falls with several other observations nearing saturation.
Most of the fog in the Spokane-cda areas is localized so opted to
leave them out of the advisory at this time but development
overnight is a strong possibility.
Meanwhile, fog advected northward from the Tri- Cities this
afternoon and into Adams, Lincoln, and Grant counties. A few
fragments even went into southwestern Whitman. With locations like
Moses Lake, Ephrata, and cams from Odessa/Coulee City indicating
visibilities near 1/4 mile or less, they will also be included in
the dense fog advisory.
Dense fog is also being reported at Wenatchee and Omak airports
but cams from these zones do not support the idea that these
restrictions are widespread at this time and thinking the
placement of the Airport on a higher bench on the outskirts of the
city could be sampling stratus than ground fog.
Nonetheless, fog is likely to continue to expand overnight and its
not out of the question that additional zones be added later on.
Temperatures have also been adjusted to only bring current
readings down a handful of degrees where low clouds and fog exist.
The biggest swings will be near Pullman and Lewiston which warmed
into the upper 50s to lower 60s and will likely drop into the
upper 30s to lower 40s. Some mid and high clouds will stream over
the region overnight and into tomorrow but confidence is not high
that these clouds will be widespread enough to alter conditions
ongoing in the boundary layer. /Sb
00z tafs: shallow stratus and fog will persist in many of the
northern valleys and Cascade valleys with LIFR conditions, which
looks to effect some of the taf sites during the period. The
exception being kpuw and klws where VFR conditions will prevail
under the southeast flow. The kgeg-kcoe corridor has cleared out
and VFR, although confidence waivers on how long they can stay
clear as satellite shows the stratus/fog just to the north. The
models indicate the stratus/fog to return toward midnight and
lasting until mid morning. Keat should remain under LIFR
conditions with some improvements of vsbys, but easterly flow
should keep it in the vicinity. For kmwh, satellite shows the
stratus deck very close to the site which could easily advect it
in. Will keep it pessimistic until mid morning. Indicated
improving conditions as a weak shortwave ripples through on
Preliminary point temps/pops...
Spokane 35 45 32 40 33 41 / 0 0 0 0 10 10
Coeur D'Alene 34 47 33 41 32 42 / 0 0 10 10 10 10
Pullman 38 50 37 46 35 46 / 0 0 10 10 10 10
Lewiston 43 52 39 51 37 50 / 0 0 10 10 10 10
Colville 31 41 30 38 31 38 / 0 0 10 10 10 0
Sandpoint 30 44 31 40 30 40 / 0 0 10 10 10 10
Kellogg 32 45 34 42 31 42 / 0 0 20 10 10 10
Moses Lake 35 42 32 41 32 43 / 10 0 0 0 0 0
Wenatchee 34 38 33 41 33 41 / 10 10 0 0 0 0
Omak 30 38 30 37 29 38 / 10 0 0 0 0 0
Idaho...dense fog advisory until noon PST Tuesday for northern Panhandle.
Washington...dense fog advisory until noon PST Tuesday for Moses Lake area-
northeast mountains-Okanogan Highlands-upper Columbia Basin.