Eastern Washington remained under an unstable weather pattern as two upper level storm systems pivoted around a broad long wave trough. The first wave approached the region on May 27th and exited into Montana on May 30th.
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Deaths and injuries are direct and indirect together, as the offices filed them. Damage is property and crops in the dollars of the year, not adjusted for inflation, and only where an office estimated it.
The episode as NWS OTX wrote it up.
Eastern Washington remained under an unstable weather pattern as two upper level storm systems pivoted around a broad long wave trough. The first wave approached the region on May 27th and exited into Montana on May 30th. On the heels of this first wave was the second, which moved into the region on May 30th and the 31st. Okanogan County saw pulse type thunderstorms containing periods of heavy rain and small hail.
The local office's own words before the first event, as it sent them, from the Iowa Environmental Mesonet's archive of National Weather Service text.
NWS Spokane, WA wrote its last area forecast discussion before the first event at May 27, 9:55 AM PST, 2 hours 25 minutes earlier.
AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE SPOKANE WA 1055 AM PDT FRI MAY 27 2011 .SYNOPSIS... A SERIES OF WEATHER SYSTEMS WILL MOVE ACROSS THE PACIFIC NORTHWEST KEEPING COOLER THAN NORMAL TEMPERATURES AND SHOWERS AROUND THE REGION THROUGH THE WEEKEND. THIS CYCLE WILL EXTEND INTO MID WEEK. && .DISCUSSION... A SHORT WAVE DISTURBANCE IS MOVING THROUGH THE REGION TODAY. SHOWERS WILL DEVELOP WITH THIS WAVE AS IT MOVES NORTHEAST THROUGH THE FORECAST AREA. A SECOND WEAKER WAVE IS EXPECTED FOR LATER THIS AFTERNOON AND MOVING IN GENERALLY THE SAME PATH. BY THIS AFTERNOON THE ATMOSPHERE WILL HAVE DESTABILIZED ENOUGH THAT EMBEDDED THUNDERSTORMS WILL BE POSSIBLE WITH THE PASSING SHOWERS. THE CONVECTION ISN'T OVERLY DEEP...BUT MALL INDICATIONS ARE THAT THERE WILL ENOUGH SEPARATION OF CHARGE WITHING THESE CONVECTIVE CELLS TO POP A FEW LIGHTING STRIKES AND ISOLATED THUNDERSTORMS WERE ADDED TO THE FORECAST. IN ADDITION POPS WERE ADJUSTED UP A BIT FOR THE BASIN TO HANDLE ADDITIONAL SHOWERS IN THE AREA. SHOWERS WILL LINGER ACROSS THE LOW LANDS THROUGH SUNSET...BUT SHOULD LINGER OVER THE HIGHER TERRAIN OF THE NORTHEAST WASHINGTON AND THE NORTH PANHANDLE IN FAVORABLE OROGRAPHIC FLOW. /TOBIN && .AVIATION... 18Z TAFS...THE ATMOSPHERE WILL DESTABILIZE THROUGH THE DAY AND WILL SUPPORT -SHRA AND POSSIBLE ISOLATED -TSRA THIS AFTERNOON. THESE SHOWERS WILL LINGER THROUGH SUNSET ACROSS THE ENTIRE FORECAST AREA. THE FOCUS SHIFTS TO THE NORTHERN AND PANHANDLE MOUNTAINS TONIGHT IN THE FAVORABLE OROGRAPHIC FLOW...WITH THE BEST CHANCE FOR -RA OVERNIGHT NORTH AND EASTS OF KGEG/KSFF/KCOE. CIGS VSBY MAINLY VFR...BUT HEAVIER SHOWERS MAY DROP CONDITIONS BRIEFLY TO MVFR/IFR. /TOBIN && .PRELIMINARY POINT TEMPS/POPS... SPOKANE 55 40 54 40 63 43 / 70 60 50 20 20 20 COEUR D'ALENE 52 39 54 38 63 41 / 70 70 50 30 40 20 PULLMAN 53 37 53 38 60 40 / 70 50 40 30 50 30 LEWISTON 59 42 58 43 64 45 / 50 50 50 20 50 20 COLVILLE 59 42 60 42 69 43 / 70 70 60 40 40 30 SANDPOINT 51 40 52 39 63 39 / 80 80 70 40 40 30 KELLOGG 47 36 48 36 57 38 / 70 70 60 50 50 40 MOSES LAKE 63 40 61 41 69 45 / 50 30 20 20 20 10 WENATCHEE 62 44 60 44 68 47 / 40 30 20 20 20 10 OMAK 62 41 62 42 69 44 / 50 60 50 20 40 20 && .OTX WATCHES/WARNINGS/ADVISORIES... ID...NONE. WA...NONE. &&
HAZARDOUS WEATHER OUTLOOK NATIONAL WEATHER SERVICE SPOKANE WA 529 AM PDT FRI MAY 27 2011 IDZ001>004-WAZ036>038-042-043-281230- NORTHERN PANHANDLE-COEUR D'ALENE AREA-IDAHO PALOUSE- CENTRAL PANHANDLE MOUNTAINS-SPOKANE AREA-NORTHEAST MOUNTAINS- OKANOGAN HIGHLANDS-EAST SLOPES NORTHERN CASCADES-OKANOGAN VALLEY- 529 AM PDT FRI MAY 27 2011 THIS HAZARDOUS WEATHER OUTLOOK IS FOR PORTIONS OF NORTH IDAHO... NORTH CENTRAL WASHINGTON AND NORTHEAST WASHINGTON. .DAY ONE...TODAY AND TONIGHT RIVERS WILL REMAIN HIGH TODAY AND TONIGHT WITH SEVERAL MAIN STEM RIVERS EXPECTED TO REMAIN ABOVE FLOOD STAGE. SMALL STREAM RIVER FLOODING WILL REMAIN POSSIBLE IN STEVENS AND FERRY COUNTIES FROM HEAVY RAINFALL THAT FELL WEDNESDAY NIGHT AND THURSDAY. .DAYS TWO THROUGH SEVEN...SATURDAY THROUGH THURSDAY THE SPRING MELT WILL CONTINUE OVER THE MOUNTAINS OF THE INLAND NORTHWEST...AND RIVERS WILL REMAIN HIGH. ADDITIONAL SHOWER ACTIVITY THIS WEEKEND AND NEXT WEEK WILL ALSO CONTRIBUTE TO RIVER RISES. IDZ026-027-WAZ031>035-041-044-281230- LEWISTON AREA-LEWIS AND SOUTHERN NEZ PERCE COUNTIES- NORTHEAST BLUE MOUNTAINS-LOWER GARFIELD AND ASOTIN COUNTIES- WASHINGTON PALOUSE-MOSES LAKE AREA-UPPER COLUMBIA BASIN- WENATCHEE AREA-WATERVILLE PLATEAU- 529 AM PDT FRI MAY 27 2011 THIS HAZARDOUS WEATHER OUTLOOK IS FOR PORTIONS OF NORTH CENTRAL IDAHO...CENTRAL WASHINGTON...EAST CENTRAL WASHINGTON...NORTH CENTRAL WASHINGTON AND SOUTHEAST WASHINGTON. .DAY ONE...TODAY AND TONIGHT NO HAZARDOUS WEATHER IS EXPECTED AT THIS TIME. .DAYS TWO THROUGH SEVEN...SATURDAY THROUGH THURSDAY NO HAZARDOUS WEATHER IS EXPECTED AT THIS TIME.
The Spokane radar (KOTX), 159 km away, was scanning. The volume nearest the first event began at 20:20 UTC.
3 hail. Local standard time, as filed.
Hail size, location, and crop damage are estimated.
Hail size, location, and crop damage are estimated.
Hail, location, and crop damage are estimated.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in Washington in 2011Every state in 2011This day in weather historyWarnings in Washington, May 2011
NOAA National Centers for Environmental Information, Storm Events Database, compiled from the National Weather Service’s monthly Storm Data. Complete through 2026-06; NCEI adds each month about 75 days after it ends and revises past years a few times a year. Rebuilt 2026-09-24. Each event’s entry at NCEI: 324943, 324949, 324953.