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fxus66 kotx 201804 
afdotx

Area forecast discussion
National Weather Service Spokane Washington
1004 am PST Mon Nov 20 2017

Synopsis...
expect wet and mild weather as a series of storm systems brings
several rounds of precipitation this week. Snow levels will be
quite high Tuesday, Wednesday, and Thursday allowing motorists to
travel over mountain passes on wet pavement. Snow levels will
begin to lower just as travelers are heading home Friday into the
weekend.




&&

Discussion...
morning update: moderate rain and some snow melt from Moscow
Mountain has led to sharp rises on Paradise creek in Moscow. The
stream is close to bankfull. Rain is expected to persist through
noon then transition toward showers. We will closely watching this
basin.

Otherwise, main changes for the forecast this morning were to
delay rising snow levels for the Methow Valley and in and around
the Okanogan Highlands. Snow levels near Republic are right around
3000 feet while snow was noted on cams as low as 1500 feet in the
Methow Valley. The threat for additional accumulations will be
low however as a robust shortwave treks into the region
transitioning steady precipitation toward showers. Sharp pressure
rises were already noted shifting on to the Washington coast and will
continue to traverse to the east the next few hours. As the cold
front presses through, lapse rates will steepen as the atmosphere
destabilizes and we expect gusty winds to accompany the frontal
passage and linger a few after afterwards. Winds on the order of
30-40kts will exist just off the deck and have the potential to
mix down the surface across portions of southeast Washington around Pomeroy, La
Crosse, and foothills of the Blue Mountains. Cannot rule out
isolated gusts of this nature across additional portions of the
basin into NE Washington and north Idaho but the threat will be lower and
isolated with any convection. Sref hints at the possibility of a
few lightning strikes; another item we will be watching for and
handling with nowcasts if necessary.

Winds are not expected to last into the evening as the low quickly
fades while encountering a cold polar high east of The Divide and
the next system reloads off the coast allowing winds to back
toward the east/southeast. /Sb




&&

Aviation...
18z tafs: a strong shortwave is tracking into the region. Steady
pcpn developing ahead of the system will lead to low cigs and
periods of light to moderate rain at the terminals. Cold front
crosses through 19-21z bringing a transition to showers and
increase in winds. This should lead to improving cigs/vis.
Midlevels clear this evening but confidence is low how this will
impact the saturated boundary layer, especially across NE Washington and
north Idaho. If stratus clears, fog will be possible as winds decr this
evening and Switch Back to the E/se. If the stratus holds firm,
this will be the main restrictions before the next moist laden
warm front arrives after 16z. Wenatchee and Moses Lake will stand
a better shot for clearing, some fog, but quicker onset of top-
down saturation with the onset of pcpn. /Sb




&&

Preliminary point temps/pops...
Spokane 46 36 47 44 54 45 / 100 10 100 100 70 50
Coeur D'Alene 45 35 45 42 54 44 / 100 40 100 100 80 50
Pullman 48 39 49 46 58 47 / 100 20 100 100 70 30
Lewiston 53 42 53 47 60 48 / 100 20 80 80 50 30
Colville 42 33 41 37 47 40 / 80 20 100 90 60 70
Sandpoint 40 32 41 39 48 41 / 100 40 100 100 90 80
Kellogg 41 34 42 40 50 43 / 100 50 100 100 80 50
Moses Lake 52 35 45 40 53 42 / 60 10 100 90 50 40
Wenatchee 48 35 41 37 49 40 / 60 10 90 40 60 30
Omak 44 34 42 38 48 43 / 70 10 90 60 60 40

&&

Otx watches/warnings/advisories...
Idaho...none.

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