Marine Weather and Tide Forecast for Leavenworth, WA

SYNOPSIS
A pattern shift arrives Friday into the weekend delivering much cooler temperatures and rain showers. In addition, there will be a chance of thunderstorms over the northern mountains at times Friday through Monday.

DISCUSSION
Tonight through Monday: The pattern begins to change tonight, as a large closed low moves into the region. Initially dry, southwest flow will continue, but by Friday the low reaches the southern WA coast. With that brings a chance of thunderstorms and increased moisture to the lower Idaho Panhandle, especially the higher terrain. As the low pushes into the southwest WA and northwest OR Friday afternoon, instability increases over north central WA. Breezy winds will also accompany this system, with gusts of 20-30 mph expected from Wenatchee and Waterville Plateau, over to Spokane and the LC Valley.

Friday night into Saturday, the low tracks along the WA/OR border before quickly moving quickly into northwest Montana. The highest precipitation chances are expected Saturday as moisture wraps around the backside of the system into eastern WA and north ID. The trough lingers through Sunday and Monday, with additional disturbances and daytime heating triggering more shower activity. Instability will be stronger, with CAPE of 500-1000 J/kg over the northern mountains Sunday, expanding into Spokane and CDA by Monday.

Tuesday and Wednesday: Ensembles are in good agreement as weak ridging building in behind the low that will warm temperatures back up above normal and dry conditions out. It may be short lived as we are starting to see another trough, while not as strong as the last sliding through the region. /KK

AVIATION
00Z TAFS: VFR conditions be place through 00z Saturday. Winds will start to pick up in the lee of the Cascades after 06z with speeds at KEAT around 15-20 kts. A band of precipitation will form over northeast OR around 5-8z Friday and move north towards KLWS-KCOE bringing a 20-40% chance for showers between 15-22z.
KPUW-KGEG-KSFF have a 10-20% chance to get brushed by this round of showers. There is a 10-20% chance of showers and isolated thunderstorms to develop between KEPH-KOMK around 21z Fri to 0z Saturday.

FORECAST CONFIDENCE AND/OR ALTERNATE SCENARIOS: High confidence for VFR conditions through 00z Saturday. Low confidence for precipitation at the TAF sites through 00z Saturday.

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Confidence descriptors:

Low - Less than a 30 percent chance Moderate - 30 to 70 percent chance High - Greater than a 70 percent chance

For additional probabilistic information for NWS Spokane airports,

please refer to the Aviation Dashboard on our webpage: https:/ www.weather.gov/otx/avndashboard

Preliminary Point Temps/PoPs
Spokane 51 69 43 57 43 66 / 10 40 30 70 70 60 Coeur d'Alene 51 66 44 55 43 64 / 10 70 50 80 80 60 Pullman 46 63 38 57 39 62 / 20 50 40 50 60 60 Lewiston 56 71 49 67 49 70 / 30 50 40 40 60 60 Colville 44 69 36 56 35 64 / 10 70 80 100 90 90 Sandpoint 49 66 43 54 42 62 / 10 70 70 100 90 80 Kellogg 54 62 45 51 45 59 / 30 70 60 90 80 70 Moses Lake 51 74 44 66 46 74 / 0 30 40 40 50 40 Wenatchee 56 70 51 66 53 73 / 0 40 40 50 40 40 Omak 51 74 45 64 46 71 / 10 80 80 80 80 70

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