Area Forecast Discussion
Issued by NWS Spokane, WA

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FXUS66 KOTX 281127
AFDOTX

Area Forecast Discussion
National Weather Service Spokane WA
427 AM PDT Tue Mar 28 2017

.SYNOPSIS...

Rain and mountain snow shower chances return this morning and will
spread south through the day, with light amounts this afternoon.
This comes ahead of another round of widespread moderate
precipitation that will arrive Tuesday night and last until early
Thursday. Friday will bring a dry break period before more
unsettled weather for next weekend.



&&

.DISCUSSION...


Today and tonight...A few orographically forced showers linger in
the panhandle mountains this morning with scattered low level
clouds relegated mainly to Idaho. Most of eastern Washington saw
clearing skies overnight which allowed most to cool into the low
to mid 30s. Given the moist BL, light winds, and clear skies, some
fog is possible in the northern valleys early this morning. IR
satellite currently shows high clouds streaming in from the
northwest, slowly advancing toward the WA/ID border by mid to late
morning. Cloud cover will continue to be on the increase through
the day in advance of our next wet system later today into
Wednesday.

Light isentropically forced rain and mountain snow will overspread
the region today enhanced by a mid level warm front moving in from
the southwest. This precip will spread southward through the day
ahead of the main event Tuesday night into Wednesday. Overall
amounts will be light for Tuesday`s rain with most only seeing a
couple hundredths if that, especially in the basin. This system
does has an ample fetch of moisture that moves in by Wednesday
morning with PWATs around a quarter inch entering the southern
zones. /bwilliam

Wednesday through Thursday Night: A warm front will spread into
the area Wednesday followed by a cold front Wednesday night into
Thursday morning. Then Thursday the trough moves through the
western US. The atmospheric river will punch inland with
widespread rain expected. Have kept our chance of precipitation
for Wed near 100%. The latest models are showing a heavier band of
rain and mountain snow continuing across portions of southeast WA
and the southern ID Panhandle Wednesday night and Thursday. Have
adjust the amount of precipitation expected across the region Wed
through Thur. The central WA valleys should see a tenth to a
quarter of an inch. Then as you head east the amounts will
increase. NE WA and N ID will see 0.40-0.60. Then as you head
south into SE WA and the southern ID Panhandle they could see
0.75-1.00 of liquid as the rain will persist at times through
Thursday. Confidence is increasing for Spokane to climb to the 2nd
wettest March spot on the climate records. Thursday night the
ridge starts to nose into the region with dry northerly flow aloft
moving in from the west. The chance of precip will continue in
the evening across portions of the ID Panhandle and SE WA. Given
the recent

*Small streams and creeks will respond to the rainfall and rise
through Friday across extreme eastern WA and north ID. Ponding of
water over roadways and fields is quite possible as well. Cannot
rule out the continued problems of debris flows, rock slides and
wash outs as the ground remains saturated from all the rain.

Friday through Tuesday: An upper level ridge builds with dry
northerly flow moving into the region on Friday, for finally a dry
day. Then Friday night into Saturday the flow turns more westerly.
Models are in terrible agreement Saturday through Monday. They all
differ on timing, strength and track of a trough that moves across
the western US. Have trended the chance of precip towards
climatology. Basically have the best chance of showers in the
mountains, and the smallest chance of precip in the Wenatchee
Valley into the Columbia Basin. Oddly enough, the models agree on
a possible ridge for early Tuesday, but am not holding out hope
that they will persist on this agreement. Temperatures will be
right at average for this time of the year...valley temps in the
50s for highs and 30s for lows. /Nisbet

&&

.AVIATION...
12Z TAFs: A weak weather system will move across the area this
afternoon for a little light rain or sprinkles at the TAF sites.
Some MVFR or IFR stratus is possible at KGEG/KSFF/KCOE this
morning, but opted to go with VFR skies in the TAFs. If any low
ceiling does form this morning it should be short lived.
Widespread rain with MVFR conditions will move into the region
around midnight tonight.  RJ

&&

.PRELIMINARY POINT TEMPS/POPS...
Spokane        49  40  52  41  52  35 /  40  80 100  80  40   0
Coeur d`Alene  47  37  49  40  51  35 /  60  80 100  80  50  10
Pullman        49  40  52  42  50  36 /  20  50 100  90  70  20
Lewiston       55  42  56  44  54  38 /  10  40  80  80  70  10
Colville       48  37  48  38  52  33 /  80  90 100  50  20   0
Sandpoint      46  34  47  36  50  33 /  80  90 100  80  40   0
Kellogg        44  35  46  37  46  35 /  50  70 100  90  80  30
Moses Lake     57  43  59  41  59  35 /  30  70 100  20  10   0
Wenatchee      53  39  54  39  56  35 /  40  80  90  20  10   0
Omak           51  39  52  37  56  34 /  60  80 100  20  10   0

&&

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

$$



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