Area forecast discussion
National Weather Service Spokane Washington
1055 PM PDT Tue may 21 2013
Synopsis...
a strong cold front will sweep through the region this afternoon
into this evening with showers...a chance of thunderstorms and
breezy winds. Cool and showery weather will continue through much
of the week, but with some improvement for the Holiday weekend.
&&
Discussion...
second update for tonight: we have gone ahead and issued an areal
Flood Watch for the northeastern corner of Washington and northern Idaho
Panhandle. 00z guidance has come in just as wet as the 18z which
brings the moderate band of pcpn currently moving into these
locations stalls the boundary through Wednesday afternoon. This
results in good model agreement of 1-1.5" of rainfall over
northern Stevens...Pend Oreille...boundary...and portions of
Bonner County. Some of these locations...already received 0.25" to
0.50" inches of rainfall today with thunderstorms. In addition,
snow levels remain high under this axis of moisture which will add
to runoff until snow levels lower near 4k above ground level around 18z
Wednesday.
Upstream...showers and isolated thunderstorms are beginning to
expand into the southwestern Columbia Basin and Wenatchee area.
The shortwave driving these showers will stretch with some of its
energy directed into the east slopes and some toward southeastern
Washington and the lower Idaho Panhandle likely to bring more rain and snow
overnight. This activity will need to be closely monitored for any
heavier showers migrating into the burn scars outside Wenatchee
but at this time...most models only bring around 0.15" with the
exception of the GFS which is closer to 0.40".
We made some changes to sky grids and pcpn chances through the
next few hours to show a break for much of the central/northern
basin and northern east slopes. /Sb
&&
Aviation...
06z tafs: several bands of rain are expected over eastern Washington
and northern Idaho tonight into Wednesday. One band will remain
nearly stationary over the far NE corner of Washington and nrn Idaho through
Wed aftn. A second disturbance will bring -shra and isold -tsra to
the kmwh-keat area tonight which will linger through much of the day
Wednesday. Showers will also expand into southeast Washington and Lewiston area
and spread northward toward kgeg-kcoe. Overall...the air mass will
be rather moist and any breaks will lead to periods of overnight fog
or stratus until either winds incr or pcpn returns. This is a low
confidence forecast across the board for timing and reductions in
cigs for most locations. /Sb
&&
Preliminary point temps/pops...
Spokane 41 51 37 61 44 61 / 20 80 20 30 10 40
Coeur D'Alene 42 48 36 61 41 60 / 100 90 30 30 20 50
Pullman 40 51 35 61 40 58 / 50 70 20 20 20 60
Lewiston 45 59 41 67 46 65 / 70 70 20 30 20 50
Colville 46 56 37 66 41 68 / 100 90 60 30 20 40
Sandpoint 45 50 37 60 40 62 / 100 100 70 40 20 40
Kellogg 42 44 35 57 42 57 / 100 90 70 30 40 60
Moses Lake 45 62 40 67 45 67 / 90 40 20 30 20 30
Wenatchee 44 57 40 65 45 65 / 90 40 30 40 20 30
Omak 44 59 36 66 41 68 / 20 80 50 40 20 30
&&
Otx watches/warnings/advisories...
Idaho...Flood Watch from 3 am PDT Wednesday through Wednesday evening
for northern Panhandle.
Washington...Flood Watch from 3 am PDT Wednesday through Wednesday evening
for northeast mountains.
&&
$$
