Marine Weather and Tide Forecast for Manson, WA

SYNOPSIS
Warmer and drier conditions return Friday through the weekend.
Unsettled weather returns Tuesday into Wednesday next week.

DISCUSSION
Saturday-Monday: Stable weather conditions return to the Inland NW through the weekend and into early next courtesy of high pressure aloft. There is high confidence for warming temperatures, dry conditions, and generally light winds. The only exception to the winds will be locally breezy east winds across the Palouse each Saturday and Sunday mornings with speeds near 15 mph. Bands of mid and high level clouds will pass through at times filtering sunshine though this moisture will be well elevated and removed from deep low pressure system that is digging southward well off the Pac NW Coast. Temperatures will warm into the upper 50s to 60s Saturday then 60-70s Sunday then 70s Monday with local readings in the low 80s around Moses Lake, Lewiston, and Omak.

Tuesday-Thursday: There is increasing confidence for an unsettled weather pattern over the Inland NW as the offshore low wobbles inland and interacts with a secondary shortwave wave dropping south from British Columbia. Precise locations where these features interact will be important and does come with moderate uncertainty. Needless to say, were are beginning to see numerous ensemble members indicating moderate to heavy rainfall for some areas of the Inland NW between late Tuesday and Wednesday night. This will come in the form of convective showers and thunderstorms and does lead to some concern for localized flooding. The pattern would also suggest at least a 5-15% chance for a few strong storms capable of gusty outflow winds and hail.

Tuesday will start off mild and dry. The offshore low will pivot into the region by Tuesday afternoon/evening with an increasing threat for showers and thunderstorms. This will be the period of greatest concern for thunderstorms with gusty outflow winds and hail. Heading into Tuesday night and Wednesday, the offshore low will drift into southern WA with the aforementioned secondary shortwave arriving from the north. The concern will be for an axis of moderate to heavy rainfall to develop in this dynamic, synoptically forced environment with some flavors of convective instability. There is little to no westerly flow in play which keeps all of the region available for the axis of heavier precipitation. Given the differences in the placement of this axis of rain, the ensemble means are not overly exciting but closer examination of individual members suggest this will be an event to watch with potential for over an inch of rainfall in some areas. Probabilities favor North Idaho, Eastern WA, and the Cascade Crest (30-60% chance) for rainfall amounts of 0.5" or more. The lee of the Cascades and Basin have a 10-30% chance for similar amounts; this is respectable for 5 days out.

Folks should be prepared for wet conditions (0.10 - 0.30") and consider what the impacts could be if 0.50-1.50" did fall in your area. Consider wrapping up or at least protect rain sensitive projects by midday Tuesday. If you have plans to venture in the backcountry, bring appropriate gear to stay dry.

Temperatures start off in the 70s Tuesday, cool into the 50-60s Wednesday, then 50s Thursday. General winds outside of thunderstorms will become gusty Wednesday into Thursday as we transition from a mild to cooler air mass. This comes with a 20-50% chance for gusts of 30 mph or greater.

Friday-Saturday: There is low confidence in this portion of the forecast what the weather pattern will be over the Inland NW.
What we do know with moderate confidence: a ridge of high pressure builds over the Gulf of AK and a trough of lower pressure settle over California. Ensembles suggest the ridge could expand over the interior Pac NW deliver warming and drying OR be impacted by waves coming down the eastern flank of the Gulf of AK ridge OR deal with shortwaves from the north/northeast as a broad area of low pressure over the Canadian Plains retrogrades and attempts to phase with the California low. Many different outcomes from mild and dry to cool and wet and breezy. Needless to say, very low confidence how this pattern will shake out with probabilities nearly split 30/30/30. /sb

AVIATION
12Z TAFS: High confidence for VFR conditions for all TAF sites with an upper-level ridge over the PNW. There will be mid and high level clouds increasing over Central and Eastern WA in response to a system well off the coast. Otherwise, mainly fair cumulus clouds in the Idaho Panhandle between 19-02z. Most sites will experience light winds of less than 10kts. PUW is the exception with a period of easterly winds around 15 knots through 19z.

FORECAST CONFIDENCE AND/OR ALTERNATE SCENARIOS: High confidence for VFR conditions through the period and increased winds for KPUW.

-----------------------

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 61 38 69 44 76 47 / 0 0 0 0 0 0 Coeur d'Alene 61 37 69 44 75 46 / 0 0 0 0 0 0 Pullman 60 39 69 45 74 48 / 0 0 0 0 0 0 Lewiston 66 40 73 47 78 50 / 0 0 0 0 0 0 Colville 63 34 72 41 78 44 / 0 0 0 0 0 0 Sandpoint 58 36 67 43 73 45 / 0 0 0 0 0 0 Kellogg 58 37 69 45 75 48 / 0 0 0 0 0 0 Moses Lake 68 40 77 46 81 49 / 0 0 0 0 0 0 Wenatchee 65 43 72 50 78 54 / 0 0 0 0 0 0 Omak 64 41 72 46 79 50 / 0 0 0 0 0 0

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