Area Forecast Discussion
Issued by NWS Spokane, WA

Home | Current Version | Previous Version | Text Only | Print | Product List | Glossary On
Versions: 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46
000
FXUS66 KOTX 221135
AFDOTX

Area Forecast Discussion
National Weather Service Spokane WA
435 AM PDT Mon May 22 2017

.SYNOPSIS...
Dry conditions with warmer temperatures are expected under a
ridge of high pressure through Tuesday. This will increase
mountain snowmelt and lead to rises on local rivers and streams
in the Cascades and across the Northern Mountains of Washington
and Idaho. A strong cold front will bring breezy conditions
Tuesday evening and Wednesday along with much cooler temperatures.
Cooler and unsettled weather will likely persist until next
weekend.

&&

.DISCUSSION...

Today...Upper level ridge of high pressure keeps North Idaho
and Eastern Washington dry and warm. Weak disturbances overtop the
weak ridge and allow for some high clouds at times.

Tonight and Tuesday...The ridge aloft flattens while its axis gets
pushed to the east and into Montana as a synoptic scale low pressure
system approaches the British Columbia Coast. Lower level thermal
ridge remains in place to keep Tuesday the warmest day of the seven
day forecast. /Pelatti

Tuesday night through Sunday...The most significant weather event
of the week appears to be shaping up for Tuesday night and
Wednesday. All the latest models are in good agreement in sweeping
a strong and tight upper low through southern British Columbia
with a trailing cold front crossing the Cascades and breaking into
the Columbia Basin during this period. This system will be
generally dry with small chances of mountain showers over the
Cascades and northern mountains...however the trajectory of the
parent upper low, gradient packing behind the front and a strong
stable layer in the mid levels behind this front will bring the
potential for windy and gusty conditions to the Cascade gaps
Tuesday night evolving into breezy to windy conditions down the
Okanogan Valley and across the basin on Wednesday. Wind Advisory
potential especially for the Cascades, the Waterville Plateau and
the Okanogan Valley will need to be analyzed and refined for
these periods as subsequent model cycles become available.

For the remainder of the period...the offending closed low will
stall over the Canadian Prairie provinces and direct some wrap
around moisture into the forecast area from the north Thursday
and Friday with cool air aloft promoting afternoon instability.
The potential exists for isolated to scattered thunderstorms over
far eastern Washington and the Idaho Panhandle each of these
afternoons.

Saturday and Sunday look like a re-establishment of a dry upper
ridge for a decreasing chance of showers and storms and a warming
trend for the region.

Temperatures over the region will register a sharp drop to below
average in the wake of the frontal passage on Wednesday with a
slowly increasing trend back to near normal on Friday and then
3 to 5 degrees above normal for the weekend. /Fugazzi

&&

.AVIATION...
12Z TAFS: A ridge of high pressure will remain over the region.
The clear skies and light winds and some high cirrus at times
will allow VFR conditions to prevail. /Pelatti

&&

.PRELIMINARY POINT TEMPS/POPS...
Spokane        80  56  82  48  62  44 /   0   0   0   0  10  10
Coeur d`Alene  79  51  81  47  62  43 /   0   0   0  10  10  20
Pullman        78  52  81  49  61  43 /   0   0   0   0   0  10
Lewiston       84  54  88  53  68  47 /   0   0   0   0   0  10
Colville       81  53  83  48  63  45 /   0   0   0   0  20  10
Sandpoint      77  48  79  44  61  40 /   0   0   0   0  20  20
Kellogg        80  46  80  43  57  40 /   0   0   0   0  20  20
Moses Lake     87  56  91  51  70  47 /   0   0   0   0   0  10
Wenatchee      85  60  88  50  67  48 /   0   0   0   0   0  10
Omak           85  57  87  49  68  48 /   0   0   0   0  10  10

&&

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

$$



USA.gov is the U.S. government's official web portal to all federal, state and local government web resources and services.