Debris Flows and Flooding in Idaho, March 28 to 31, 2012

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SPOKANE WA
1032 PM PDT Tue Mar 27 2012

.SYNOPSIS...
A maritime conga line of Pacific storms will splash through the
region with generally valley rain and mountain snow every 24
hours through the next week. Occasionally windy conditions will be
likely with some of these storm fronts.

&&

.DISCUSSION...
Update: forecast remains on track with waves of precipitation
coming across the Inland Northwest. One swath of rain is spreading
through the Highway 2 and Highway 95 corridors, while a second
swath is coming up through the Columbia Basin. Pops were increased
across parts of the southeast forecast area, from the upper
Columbia Basin through the Palouse through the night. I also
increased QPF amounts slightly across the north and eastern
forecast areas, by few hundredth or so. Overnight lows were
adjusted upward a few degrees as well, as the moist atmosphere and
cloud cover should hold things up.

The winter weather advisory for the Cascades above 4000 feet looks
on track, where temperatures are largely at freezing or below.
Blewett Pass has reported a rain/snow mix but I expect it should
turn to mainly snow as the night progresses and accumulation
should pick up. /J. Cote'

&&

.AVIATION...
06Z TAFS: A Pacific systems will continue to bring periods of rain
to the region tonight and early Wednesday, before becoming showery
in the afternoon. The deepest moisture and strongest forcing will
be along the Cascades tonight...and KEAT will likely experience
prolonged IFR ceilings until the trailing cold front passes
through around 10Z-12Z Wednesday. Elsewhere all TAF sites except
KLWS will generally experience MVFR ceilings in -RA...with low VFR
and occasional brief MVFR ceilings at KLWS.

After the cold front passage early Wednesday morning (around 10Z
at KEAT and 16Z at KGEG) steady rain will become scattered -SHRA
with a possibility of isolated TSRA during the afternoon mainly
north of Interstate 90. /J. Cote'

&&

.PRELIMINARY POINT TEMPS/POPS...
Spokane        40  54  38  48  37  52 /  90  90  40 100  60  80
Coeur d'Alene  38  52  35  45  35  50 /  90  90  40 100  80  80
Pullman        39  49  35  45  36  51 /  80  90  30  90  70  80
Lewiston       44  55  38  51  39  58 /  60  70  30  70  60  80
Colville       38  55  35  49  37  53 / 100  90  50 100  70  80
Sandpoint      38  50  33  43  36  46 /  90 100  50 100  90 100
Kellogg        34  47  31  42  35  45 /  80 100  50 100  90 100
Moses Lake     42  62  40  58  39  57 /  80  30  40  80  20  70
Wenatchee      37  59  38  54  38  53 /  90  30  60  80  30  70
Omak           37  59  35  52  35  53 / 100  60  60 100  20  60

&&

.OTX WATCHES/WARNINGS/ADVISORIES...
ID...None.
WA...Winter Weather Advisory until 5 PM PDT Wednesday for East Slopes
     Northern Cascades.

&&

HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE SPOKANE WA
610 AM PDT TUE MAR 27 2012

IDZ003-026-027-WAZ031>033-281315-
IDAHO PALOUSE-LEWISTON AREA-LEWIS AND SOUTHERN NEZ PERCE COUNTIES-
NORTHEAST BLUE MOUNTAINS-LOWER GARFIELD AND ASOTIN COUNTIES-
WASHINGTON PALOUSE-
610 AM PDT TUE MAR 27 2012

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

.DAY ONE...TODAY AND TONIGHT

AREA STREAMS WILL CONTINUE TO RECEDE...WITH THE PALOUSE RIVER
BASIN BEING THE LAST TO FALL BELOW BANKFULL. A FLOOD WARNING
CONTINUES FOR THE PALOUSE RIVER AT POTLATCH THROUGH THIS EVENING.

.DAYS TWO THROUGH SEVEN...WEDNESDAY THROUGH MONDAY

A SERIES OF WET AND MILD STORM SYSTEMS WILL MOVE ACROSS THE AREA
THROUGH THE WEEK. THESE WILL CARRY THE POTENTIAL FOR ADDITIONAL
SIGNIFICANT RAINFALL AMOUNTS...INCLUDING IN AREAS WHICH HAVE
ALREADY SEEN SIGNIFICANT RAINS SUCH AS THE PALOUSE RIVER BASIN.
COMBINED WITH SNOW MELT THIS WILL CONTINUE TO SUPPORT ELEVATED WATER
LEVELS ON RIVERS...CREEKS AND STREAMS...WITH FLOODING POTENTIAL
HERE AND IN POOR DRAINAGE AREAS. THERE IS ALSO A POSSIBILITY OF
MUD SLIDES AND DEBRIS FLOWS ON STEEP AND SPARSELY VEGETATED
SLOPES.

IDZ001-002-004-WAZ034>038-041>044-281315-
NORTHERN PANHANDLE-COEUR D'ALENE AREA-CENTRAL PANHANDLE MOUNTAINS-
MOSES LAKE AREA-UPPER COLUMBIA BASIN-SPOKANE AREA-
NORTHEAST MOUNTAINS-OKANOGAN HIGHLANDS-WENATCHEE AREA-
EAST SLOPES NORTHERN CASCADES-OKANOGAN VALLEY-WATERVILLE PLATEAU-
610 AM PDT TUE MAR 27 2012

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

.DAY ONE...TODAY AND TONIGHT

NO HAZARDOUS WEATHER IS EXPECTED AT THIS TIME.

.DAYS TWO THROUGH SEVEN...WEDNESDAY THROUGH MONDAY

A SERIES OF WET AND MILD STORM SYSTEMS WILL MOVE ACROSS THE AREA
THROUGH THE WEEK. THESE WILL CARRY THE POTENTIAL FOR ADDITIONAL
SIGNIFICANT RAINFALL AMOUNTS. COMBINED WITH SNOW MELT THIS WILL
SUPPORT RISING LEVELS ON RIVERS...CREEKS AND STREAMS...WITH
FLOODING POTENTIAL HERE AND IN POOR DRAINAGE AREAS. THERE IS ALSO
A POSSIBILITY OF MUD SLIDES AND DEBRIS FLOWS ON STEEP AND SPARSELY
VEGETATED SLOPES.