Scientific Forecaster Discussion
Area forecast discussion
National Weather Service Spokane Washington
513 PM PDT Sat Jul 30 2016
dry and breezy weather will peak by late afternoon and early
evening, continuing the concerns for rapidly spreading wildfires.
Sunday and Monday will be more seasonal temperatures with less
wind. Another potent cold front is expected on Tuesday, and will
likely produce more windy weather as well as the chance for
thunderstorms along the Canadian border. Dry and warmer weather is
expected late next week.
tonight through monday: the inland northwest will be under the influence
of dry westerly flow, as an upper level low pressure system sits
to the north and a Flat Ridge of high pressure lies to the south.
Within the westerly flow, a jet stream of 80-90kt will be found
aloft. A dry cold front will exit north Idaho this evening. In the
wake of this system, westerly surface winds remain breezy and
gusty from the afternoon and into the evening across the low lands
of eastern Washington. Expect gusts of 30-40 mph early this
evening with the possibility of patchy blowing dust. The breezy
conditions in combination with low relative humidities with values
in the teens will keep the region on alert for rapid fire spread.
A red flag warning remains in effect for much of eastern
Washington through 9 PM. The gustiness will taper off overnight in
most locations, except for the Cascade gaps, Waterville Plateau
and the western basin where gusty winds will likely continue until
early Sunday morning. Overnight temperatures will remain mild with
the increased winds. Dry westerly flow will continue on Sunday
with temperatures about 5 degrees cooler than today and locally
breezy conditions by the afternoon. Due to the dry atmosphere, the
chances of convection will be low but the best area would be along
or north of the Canadian border. The low pressure system in British Columbia
shifts east on Monday allowing for a shortwave ridge of high
pressure to build and temperatures to warm. Surface winds back to
the south for Monday as temperatures climb a few degrees, placing
them near normal for the start of August. /Rfox.
Monday evening through tuesday: the GFS has slowed down the
timing just a bit of the closed low to move into the region, but
the European model (ecmwf) has very similar timing and track as the previous run.
The closed low and strong cold front will push through during the
late overnight hours Monday night into early Tuesday morning for
the Cascades and then Tuesday morning and afternoon for eastern Washington
and north Idaho. Winds will increase starting Monday evening and will
continue through the day on Tuesday. The strongest sustained winds
will occur Tuesday afternoon and evening after the front GOES
through. However a 90+ kt jet will move into the Cascades early
Tuesday morning accompanying the front and could produce for a
short duration very gusty winds for the east slopes of the
Cascades and into the Columbia Basin. The best chance for showers
and thunderstorms with this front will be across the north, north
of Highway 2. The threat of showers and thunderstorms will
decrease in the evening as the low moves into southern Alberta.
Tuesday will be the coolest day of the week with valley
temperatures in the 70s to lower 80s.
Wednesday through saturday: the low keeps moving east as a
shortwave ridge builds along the west side of the state. Wednesday
temperatures will remain below average in the wake of the cold
front. There is the potential for some additional showers and
thunderstorms along the Canadian border in the afternoon.
Otherwise we dry out. The ridge shifts east over eastern Washington and
north Idaho Thursday as the next closed low begins to move out of the
Gulf of Alaska and into British Columbia. There are model
differences as to how far south to bring the low which could have
implications for next weekend. For now kept the forecast dry and
temperatures near average. /Nisbet
00z tafs: windy conditions expected into the early evening. Wind
gusts of 20-30 kts are expected through 03z. Gusts will taper off
at most taf sites through the evening as the atmosphere decouples.
The exception will be at keat where gusts of 20-25 kts are
expected through 09z before pressure gradients weaken into Sunday
morning. A fire burning in the upper Columbia Basin will spread
smoke into the Spokane/Coeur D'Alene corridor this evening. No
visibility restrictions are expected at the surface as smoke is
expected to be at mid level in the atmosphere. /Svh
Preliminary point temps/pops...
Spokane 57 82 55 86 58 75 / 0 0 0 0 0 0
Coeur D'Alene 55 80 51 85 55 75 / 0 0 0 0 0 0
Pullman 49 81 45 86 52 75 / 0 0 0 0 0 0
Lewiston 60 89 56 93 61 83 / 0 0 0 0 0 0
Colville 53 84 49 87 52 77 / 0 0 0 0 0 30
Sandpoint 52 78 46 82 50 74 / 0 0 0 0 0 10
Kellogg 53 77 49 84 52 71 / 0 0 0 0 0 0
Moses Lake 56 88 53 89 57 81 / 0 0 0 0 0 0
Wenatchee 63 86 60 88 61 78 / 0 0 0 0 10 10
Omak 59 87 56 89 60 78 / 0 0 0 0 10 30
Washington...red flag warning until 9 PM PDT this evening for East Washington
central Cascade valleys (zone 677)-East Washington northern
Columbia Basin (zone 673)-East Washington Palouse and
Spokane area (zone 674).