River Flood Watch 4, NWS Spokane, WA

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SPOKANE WA
433 AM PDT Mon Mar 10 2014

.SYNOPSIS...

Another wet day for southeastern Washington and north Idaho is
expected today...with showers and possibly a few thunderstorms
over much of eastern Washington. Flooding once again may be an
issue with this very wet storm. Snow levels will remain high
enough to not pose a significant threat to any passes or higher
elevation routes. High pressure will then build in after today for
drier and mild conditions. Following this dry period will be an
increased threat of valley rain and mountain snow beginning
Friday.

&&

.DISCUSSION...
Today and tonight...Dawn breaks today with satellite revealing a
baroclinic leaf structure over the northwest US...indicative of a
an area of cyclogenesis featuring a shield of moist isentropic
ascent over Washington...being undercut by an approaching
occlusion moving into western Oregon. This whole rat's nest is
generously fueled by by a deep fetch of sub-tropical moisture
welling up the eastern flank of an offshore Pacific trough.

It will take most of the day today for this storm system to
noticeably begin clearing the region to the east...followed by a
bleed of cooler Canadian air feeding through the Okanogan valley
tonight and gradually exchanging the current temperate Maritime
air mass with a dry polar Continental air mass.

Today will feature two weather regimes over the area. In the
cascades Lee and deep basin a small chance of light rain this
morning will give way to clearing skies and increasingly breezy
northerly/northwest winds as the new air mass begins to invade.

Over the eastern zones...say east and north of a line from
Republic to Walla Walla another round of morning stratiform light
rain...with periods of moderate rain over the Palouse and points
south will occur as the isentropic precipitation shield north of
the main surface low development transits the region. By afternoon
the parent offshore trough will eject inland forcing the main
moisture feed to the east into Montana and central Idaho...but
also destabilizing the air mass with a cold inter-trough pool
aloft. Morning stratiform rain will transition to a hit-and-miss
shower regime with an added threat of weak and short lived
thunderstorms into the early evening hours. A drying and clearing
trend will commence tonight as the air mass stabilizes shortly
after sunset and dry air infiltrates most of the basin by dawn
Tuesday.

Hydrology concerns are now front and center for the Idaho
Panhandle. Many locations in Shoshone county have received upwards
of 1 inch of rain in the last 24 hours...with snow levels
remaining near 5000+ feet. another 1/3 to 2/3 of an inch is
possible today and this will certainly lead to some robust
responses on the rivers and streams emptying these mountains.
At this time a flood warning for the Coeur D'Alene at Cataldo
remains i effect...and there is an increasing likelihood that the
St. Joe river will also achieve Flood Stage today and into
Tuesday. The situation will be closely monitored over the coming
few days. /Fugazzi

Tuesday to Friday night: High pressure and dry weather dominates,
before light shower chances return late week. Tuesday an upper
trough exits and high pressure build in. The threat of
precipitation shifts toward the lower Panhandle and wanes. Look
for some morning stratus and patchy fog about the lower Panhandle
and Palouse. Patchy fog is also possible about the sheltered
northern and Cascade valleys Tuesday morning, as well as later
Tuesday night into Wednesday morning. Late Wednesday into Thursday
a weak wave passes. However the lift and deeper moisture remains
north of the Canadian border. Some passing middle and high clouds
are expected but otherwise dry weather. Patchy fog will be a
lingering threat in the sheltered valleys. Thursday night and
Friday a second and third wave pass. Each tracks slightly further
south and carries a bit more moisture. So Thursday night look for
some light shower chances around the northern mountains. Friday a
broader shower threat expands throughout the mountains and eastern
lowlands (including the Spokane/C'dA area and higher Palouse),
before dissipating Friday night. Friday's wave looks to come with
breezy to locally windy conditions, especially in the afternoon
and evening. Overall, models do not generate much precipitation
out of these waves. In other words the days do not look like a
wash-out by any means. Temperatures will be closer to seasonal
norm at the start of the period, then slowly warm above normal
into Thursday and Friday. /J. Cote'

Saturday and Sunday: A ridge pattern is expected to be in place
for the beginning of the period. This will promote a fairly dry and
warm Saturday. This will continue into through most of the day on
Sunday. The models are indicating the ridge breaking down and the
next system moving into the region by late Sunday. The models do
not agree on the timing of a disturbance. This disturbance is
expected to bring breezy winds and light amounts of precip. The
best precip chances are limited to the higher terrain of the
mountains. Temperatures will be slightly above the season normals.
/JDC

&&

.AVIATION...
12Z TAFS: The first 6-8 hours of the forecast period will feature
widespread MVFR ceilings and vis in -RA over the eastern TAF sites
as a moist occluded front transits the region. The KMWH and KEAT
TAF sites will be largely skipped by this weather system for
mainly VFR conditions. After 18Z-20Z steady pcpn will taper off to
scattered to numerous showers. Instability generated by the
passage of a cool upper trough this afternoon will create a risk
of isolated TSRA east of a line from KOMK to KALW. Conditions will
improve to mainly VFR but a chance of brief MVFR ceilings in
shower cores. Beginning after 00Z and continuing through the end
of the TAF period dry continental air will invade the region and
bring clearing skies with VFR conditions to all TAF sites. /MJF

&&

.PRELIMINARY POINT TEMPS/POPS...
Spokane        52  30  46  27  51  32 /  60  20   0   0   0   0
Coeur d'Alene  50  29  45  26  51  29 /  60  20   0   0   0   0
Pullman        49  32  47  30  53  33 / 100  40   0   0   0   0
Lewiston       56  35  53  33  59  36 / 100  50   0   0   0   0
Colville       53  29  54  26  54  28 /  30  20   0   0   0   0
Sandpoint      47  28  44  25  47  27 /  60  20   0   0   0  10
Kellogg        44  30  46  29  50  31 /  90  40  10   0   0   0
Moses Lake     60  32  53  30  55  32 /  20  10   0   0   0   0
Wenatchee      58  32  52  32  54  34 /  20   0   0   0   0   0
Omak           56  28  50  28  52  30 /  10   0   0   0   0   0

&&

.OTX WATCHES/WARNINGS/ADVISORIES...
ID...None.
WA...None.
&&

HAZARDOUS WEATHER OUTLOOK...UPDATED
NATIONAL WEATHER SERVICE SPOKANE WA
1041 AM PDT SUN MAR 9 2014

WAZ034-035-038-041-043-044-101745-
MOSES LAKE AREA-UPPER COLUMBIA BASIN-OKANOGAN HIGHLANDS-
WENATCHEE AREA-OKANOGAN VALLEY-WATERVILLE PLATEAU-
1041 AM PDT SUN MAR 9 2014

THIS HAZARDOUS WEATHER OUTLOOK IS FOR PORTIONS OF CENTRAL
WASHINGTON...EAST CENTRAL WASHINGTON AND NORTH CENTRAL
WASHINGTON.

.DAY ONE...TODAY AND TONIGHT

NO HAZARDOUS WEATHER IS EXPECTED AT THIS TIME.

.DAYS TWO THROUGH SEVEN...MONDAY THROUGH SATURDAY

NO HAZARDOUS WEATHER IS EXPECTED AT THIS TIME.

IDZ001>004-WAZ033-036-037-042-101745-
NORTHERN PANHANDLE-COEUR D'ALENE AREA-IDAHO PALOUSE-
CENTRAL PANHANDLE MOUNTAINS-WASHINGTON PALOUSE-SPOKANE AREA-
NORTHEAST MOUNTAINS-EAST SLOPES NORTHERN CASCADES-
1041 AM PDT SUN MAR 9 2014

THIS HAZARDOUS WEATHER OUTLOOK IS FOR PORTIONS OF NORTH IDAHO...
NORTH CENTRAL WASHINGTON...NORTHEAST WASHINGTON AND SOUTHEAST
WASHINGTON.

.DAY ONE...TODAY AND TONIGHT

ANOTHER WET WEATHER SYSTEM WILL BRING MODERATE TO HEAVY RAINFALL
TO THE AREA THROUGH TODAY. RAINFALL COMBINED WITH SOME MID
ELEVATION SNOW MELT WILL RESULT IN RISES TO AREA RIVERS AND SMALL
STREAMS. MAIN STEM RIVERS DRAINING THE IDAHO PANHANDLE MOUNTAINS
WILL RUN HIGH AND SOME LOCATIONS MAY ACHIEVE MINOR FLOOD STAGE BY
EARLY NEXT WEEK. OTHER HAZARDS MAY INCLUDE MUDSLIDES OR DEBRIS
FLOWS AND POSSIBLY SOME DAMAGE TO AREA ROADWAYS IF CULVERTS BECOME
CLOGGED.

.DAYS TWO THROUGH SEVEN...MONDAY THROUGH SATURDAY

AREA RIVERS AND SMALL STREAMS WILL CONTINUE TO RUN HIGH THROUGH AT
LEAST EARLY NEXT WEEK...ESPECIALLY IN THE CENTRAL IDAHO PANHANDLE.
A SECOND WEATHER SYSTEM WILL ARRIVE TONIGHT AND IS EXPECTED TO
CLIP THE SOUTHERN PORTION OF THE CENTRAL IDAHO PANHANDLE. AT THIS
TIME...THE BULK OF THIS RAINFALL IS ANTICIPATED TO HEAD SOUTH OF
THE RIVER BASINS DRAINING OUT OF THE CENTRAL PANHANDLE MOUNTAINS.

IDZ026-027-WAZ031-032-101745-
LEWISTON AREA-LEWIS AND SOUTHERN NEZ PERCE COUNTIES-
NORTHEAST BLUE MOUNTAINS-LOWER GARFIELD AND ASOTIN COUNTIES-
1041 AM PDT SUN MAR 9 2014

THIS HAZARDOUS WEATHER OUTLOOK IS FOR PORTIONS OF NORTH CENTRAL
IDAHO AND SOUTHEAST WASHINGTON.

.DAY ONE...TODAY AND TONIGHT

NO HAZARDOUS WEATHER IS EXPECTED AT THIS TIME.

.DAYS TWO THROUGH SEVEN...MONDAY THROUGH SATURDAY

ANOTHER WET WEATHER SYSTEM WILL BRING MODERATE TO HEAVY RAINFALL
TO THE LASTING THROUGH MONDAY. THIS WILL RESULT IN RISES IN AREA
RIVERS AND SMALL STREAMS. SOME LOCATIONS MAY ACHIEVE MINOR FLOOD
STAGE BY EARLY NEXT WEEK. OTHER HAZARDS MAY INCLUDE MUDSLIDES OR
DEBRIS FLOWS AND POSSIBLY SOME DAMAGE TO AREA ROADWAYS IF CULVERTS
BECOME CLOGGED.