A strong upper-level ridge during the end of July and beginning August helped fuel a  moist and unstable air mass over the region.  The ridge broke down on the 1st of August and was overrun by two weak midlevel impulses on August 2nd.  As the second impulse passed over Central Washington during the late afternoon, strong to severe storms developed over the Waterville Plateau producing a combination of heavy rain and moderate size hail.  Meanwhile, dewpoint depressions over Eastern Washington had grown between 40 and 50 degrees Fahrenheit.  The rain and hail cooled outflow winds from storms over the Waterville Plateau spread east and gained momentum while tracking along the Highway 2 corridor across the Upper Columbia Basin.  Additional storms fired along the gust front and continued to reinforce the cold pool and resultant winds.  Gusty winds and blowing dust which originated over the Waterville Plateau traveled across Banks Lake and through much of Lincoln County but generally remained below severe speeds.  It wasn't until the outflow boundary moved into Eastern Lincoln County and Lake Roosevelt near Seven Bays Marina when wind speeds ranged between 60 and 70 miles per hour.  The winds led to numerous downed trees, waves four to six feet on Lake Roosevelt, widespread boat damage, power outages, and structural damage.  The winds also fanned new wildfire starts from lightning.  As the afternoon progressed, a combination of forcing from the shortwave and gust front continued to fuel additional storms over Northeastern Washington.   Outflow winds from these storms generally moved north to south.  As the north to south boundaries interacted with the westerly boundaries, some locations were spared experiencing wind gusts between 35 and 45 mph.  In this absence, winds of 50 to 70 mph were observed coupled with widespread tree damage.  A few storms briefly produced quarter size hail between Davenport and Northwest Spokane.

Thunderstorm Wind in STEVENS, WASHINGTON
From 02-AUG-14 16:00:00 to 02-AUG-14 17:05:00 (PST-8)
Location: BLUE CREEK CAMP
Magnitude: 61.00 MG
Property damage: 800.00K
Crop damage: 0.00K
Reported by: Broadcast Media

The Midnight Mine RAWS measured a wind gust of 68 mph.  Numerous boats were damaged on Lake Roosevelt due to the winds.  Boaters and videos indicated wind waves of four to six feet on the Lake.  At least ten boats were severely damaged, two boats capsized, and numerous other boats received minor damage.  Several docks were damaged.  No injuries were reported.  Numerous trees were downed across southern Stevens County.

Thunderstorm Wind in OKANOGAN, WASHINGTON
From 02-AUG-14 12:40:00 to 02-AUG-14 13:40:00 (PST-8)
Location: CARLTON
Magnitude: 50.00 EG
Property damage: 40.00K
Crop damage: 0.00K
Reported by: Emergency Manager

A thunderstorm that passed over the Methow Valley produced wind gusts that knocked down power lines and toppled trees.  Several roads were temporarily closed from downed trees including Highway 20, Highway 153, and Twin Lakes Road.  Several residences in Twisp and Winthrop area were damaged when trees hit the homes or landed on roofs.  Lightning also sparked new wildfires within the Methow Valley, one which grew large and became known as the Little Bridge Creek Wildfire.

Thunderstorm Wind in PEND OREILLE, WASHINGTON
From 02-AUG-14 17:00:00 to 02-AUG-14 17:15:00 (PST-8)
Location: CAMDEN
Magnitude: 52.00 EG
Property damage: 100.00K
Crop damage: 0.00K
Reported by: Broadcast Media

Thunderstorm winds knocked down trees which blocked State Route 211.  Strong winds also led to numerous areas of tree damage between Newport and the Spokane County border along Highway 2.

Thunderstorm Wind in FERRY, WASHINGTON
From 02-AUG-14 15:20:00 to 02-AUG-14 15:38:00 (PST-8)
Location: KELLER
Magnitude: 84.00 MG
Property damage: 40.00K
Crop damage: 0.00K
Reported by: Public

The operator of the Keller Ferry reported winds clocked at 84 mph.

Thunderstorm Wind in LINCOLN, WASHINGTON
From 02-AUG-14 15:56:00 to 02-AUG-14 16:40:00 (PST-8)
Location: CRESTON
Magnitude: 52.00 EG
Property damage: 2.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Trained spotter three miles southwest of Miles estimated winds between fifty and sixty miles per hour.  A secondary thunderstorm cell that developed along the gust front produced hail to the size of quarters briefly three miles southwest of Miles.

Thunderstorm Wind in STEVENS, WASHINGTON
From 02-AUG-14 16:00:00 to 02-AUG-14 17:05:00 (PST-8)
Location: BLUE CREEK CAMP
Magnitude: 61.00 MG
Property damage: 300.00K
Crop damage: 0.00K
Reported by: Broadcast Media

The Midnight Mine RAWS measured a wind gust of 68 mph.  Numerous boats were damaged on Lake Roosevelt due to the winds.  Boaters and videos indicated wind waves of four to six feet on the Lake.  At least ten boats were severely damaged, two boats capsized, and numerous other boats received minor damage.  Several docks were damaged.  No injuries were reported.  Numerous trees were downed across southern Stevens County.

Thunderstorm Wind in SPOKANE, WASHINGTON
From 02-AUG-14 16:36:00 to 02-AUG-14 17:15:00 (PST-8)
Location: HITE
Magnitude: 56.00 EG
Property damage: 2.00M
Crop damage: 0.00K
Reported by: NWS Employee

Numerous trees were downed or snapped across Northern Spokane County including the communities of Deer Park, Chattaroy, Colbert, Mead, Nine Miles Falls, and Spokane north of Interstate 90 due to a west to east tracking outflow boundary.  A second cell developed along the boundary producing quarter size hail over Five Mile Prairie and sent an outflow boundary north to south across the South Hill and Spokane Valley roughly thirty minutes after the initial gust front went through.  A NWS employee stated winds associated with this boundary were less than 25 mph but witnessed a tree fall down.  Due to its isolated nature, it is assumed that this tree was damaged from a storm two weeks earlier.  Significant damage was observed from northwestern Spokane to Chattaroy to the Pend Oreille County border.  The Riverside Mobile Home Park was hit hard for a second time in as many weeks and forced to evacuate.  Numerous trees fell on homes.  One home on North Echo Road suffered major structural damage.  The nearby Eloika Lake Resort lost eight trees in the storm.  The trees damaged a home, RVs, and vehicle.  The resort which lost 48 trees in a storm ten days earlier was forced to shut down for the remainder of the summer.

Thunderstorm Wind in OKANOGAN, WASHINGTON
From 02-AUG-14 15:58:00 to 02-AUG-14 16:28:00 (PST-8)
Location: BELVEDERE
Magnitude: 52.00 EG
Property damage: 2.00K
Crop damage: 0.00K
Reported by: Law Enforcement

Trees and power lines were blown down from thunderstorm winds across portions of Nespelem.