Tornado in Oregon, November 6, 2009

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PORTLAND OR
825 PM PST FRI NOV  6 2009

.SYNOPSIS...A COOL AIR MASS WILL REMAIN OVER THE REGION THROUGH THE
WEEKEND. THIS PATTERN WILL MAINTAIN SHOWERS AND EVEN A FEW
THUNDERSTORMS THROUGH SAT. EXPECT HEAVY SNOW AT TIMES IN THE
CASCADES. CONDITIONS WILL DRY OUT A BIT SUNDAY...BUT WET WEATHER
RETURNS FOR MONDAY.

&&

.SHORT TERM...KRTX RADAR INDICATES AN ENHANCED BATCH OF SHOWERS
APPROACHING THE NORTH OREGON COAST THIS EVENING. A FEW THUNDERSTORMS
ARE POSSIBLE AS WELL AS THIS AREA OF SHOWERS MOVES ONSHORE AND INTO
THE NORTH OREGON COAST RANGE. ANY THUNDERSTORMS THAT DO DEVELOP MAY
STILL PRODUCE SMALL HAIL AND BRIEF GUSTY WINDS.

OVERALL PATTERN NOT CHANGING MUCH OVER THE NEXT DAY OR SO. A STRONG
UPPER LOW OVER THE EASTERN GULF OF ALASKA WILL MAINTAIN MODERATE
ONSHORE FLOW THROUGH SAT EVENING. EMBEDDED DISTURBANCES WILL KEEP
ROUNDS OF SHOWERS...AND EVEN A COUPLE BANDS OF STEADY
PRECIP...ARRIVING. MODELS ARE IN GOOD AGREEMENT SHOWING THE ENHANCED
BAND CURRENTLY APPROACHING THE COAST MOVING THROUGH LATER TONIGHT
WITH A STRONGER BAND LATE SAT OR SAT EVENING WHICH MAY GIVE A PERIOD
OF STEADY PRECIP.

SNOW LEVELS WILL HOVER BETWEEN 3500 AND 4000 FEET THROUGH SAT...THEN
POSSIBLY DROP SLIGHTLY SAT NIGHT BEHIND THAT DISTURBANCE. WITH PLENTY
OF PRECIP AND FAVORABLE W 850 MB FLOW...2 TO 3 FT OF NEW SNOW SEEMS
REASONABLE BETWEEN NOW AND LATE SAT NIGHT FOR THE CASCADES. CURRENT
WINTER WEATHER ADVISORY OKAY RATHER THAN WINTER STORM WARNING DUE TO
FACT THAT THE ACCUMULATIONS WILL BE MODERATE BUT MAINLY SPREAD OUT
OVER TIME.

MODELS CONTINUE TO SHOW ANOTHER STRONG LOW SPINNING UP IN THE E GULF
OF ALASKA ON SUN AND MON. THIS WILL RESULT IN SOME RIDGING OVER PAC
NW LATER SUN AND SUN NIGHT...WITH MOSTLY DRY WEATHER. HOWEVER...
WILL BE A SHORT LIVED BREAK AS THAT SYSTEM WILL SEND A FRONT INTO
PAC NW ON MON.

.LONG TERM...NO CHANGES. PREVIOUS DISCUSSION FOLLOWS...SNOW LEVELS
WILL START FALLING AGAIN MONDAY NIGHT AS THE NEXT STRONG FRONTAL
SYSTEM MOVES ACROSS THE CASCADES AND THE COOL UPPER LEVEL TROUGH
MOVES IN BEHIND IT. SHOWERY WEATHER WITH SNOW LEVELS BETWEEN 3000
AND 4000 FT WILL PERSIST THROUGH WEDNESDAY MORNING. EXTENDED MODELS
ARE CURRENTLY SHOWING THE UPPER LEVEL TROUGH WEAKENING OUT ON
WEDNESDAY TO BE REPLACE BY A RIDGE ON THURSDAY AND FRIDAY.  IF THIS
TREND HOLDS TRUE DRIER WEATHER IS POSSIBLE FOR A COUPLE OF DAYS.
RUTHFORD.

&&

.AVIATION...MOSTLY VFR WITH LOCAL MVFR CIGS/VSBYS AND SMALL HAIL ARE
POSSIBLE IN SHOWERS AND THUNDERSTORMS AS ANOTHER TROUGH MOVES INLAND
TONIGHT. THESE SHOWERS/ISOLATED TSTMS SHOULD MOVE SE ACROSS THE
WILLAMETTE VALLEY BETWEEN 05Z-09Z. YET ANOTHER FRONT EXPECTED TO
MOVE ONSHORE WITH MORE SHOWERS DURING THE DAY SAT.

KPDX AND APPROACHES...MAINLY VFR...BUT BRIEF MVFR CIGS/VSBYS
POSSIBLE IN SHOWERS/ISOLATED TSTMS AS TROUGH MOVES THROUGH PDX METRO
BETWEEN 06Z-09Z.

&&

.MARINE...MAIN CONCERN THROUGH SATURDAY WILL BE THE VERY LARGE SEAS
BEGINNING TO MOVE INTO THE COASTAL WATERS. THESE SWELLS WERE
GENERATED BY A STRONG LOW IN THE GULF OF ALASKA. W-NW SWELLS OF
23-27 FT WILL IMPACT THE COASTAL WATERS THROUGH SAT AFTERNOON...THEN
VERY GRADUALLY SUBSIDE SAT NIGHT THROUGH EARLY NEXT WEEK. A COLD
FRONT SAT AFTERNOON MAY BRING BRIEF GALES...WITH A BETTER CHANCE FOR
GALES WITH A STRONGER FRONT ANTICIPATED SUN NIGHT/MON.

&&

.PQR WATCHES/WARNINGS/ADVISORIES...
WA/OR...SMALL CRAFT ADVISORY FOR WINDS FROM CAPE SHOALWATER TO
 FLORENCE THROUGH SATURDAY EVENING.
SMALL CRAFT ADVISORY FOR HAZARDOUS SEAS FROM CAPE SHOALWATER
 TO FLORENCE THROUGH SUNDAY.
HIGH SURF WARNING SOUTH WASHINGTON...NORTH AND CENTRAL
 OREGON COAST THROUGH SATURDAY.
SMALL CRAFT ADVISORY FOR ROUGH COLUMBIA RIVER BAR IN
 EFFECT THROUGH SUNDAY.
WINTER WEATHER ADVISORY FOR SNOW FOR THE CASCADES OF SOUTH
  WASHINGTON...NORTH AND CENTRAL OREGON CONTINUES THROUGH
  SAT NIGHT.

&&

MORE WEATHER INFORMATION ONLINE AT...
HTTP://WEATHER.GOV/PORTLAND

THIS DISCUSSION IS FOR NORTHWEST OREGON AND SOUTHWEST WASHINGTON FROM
THE CASCADE CREST TO 60 NAUTICAL MILES OFFSHORE. THE AREA IS COMMONLY
REFERRED TO AS THE FORECAST AREA.

HAZARDOUS WEATHER OUTLOOK...CORRECTED
NATIONAL WEATHER SERVICE PORTLAND OR
543 AM PST FRI NOV 6 2009

PZZ250-255-270-275-071345-
COASTAL WATERS FROM CAPE SHOALWATER WA TO CASCADE HEAD OR OUT
10 NM-COASTAL WATERS FROM CASCADE HEAD TO FLORENCE OR OUT 10 NM-
WATERS FROM CAPE SHOALWATER WA TO CASCADE HEAD OR FROM 10 TO
60 NM-WATERS FROM CASCADE HEAD TO FLORENCE OR FROM 10 TO 60 NM-
543 AM PST FRI NOV 6 2009

THIS HAZARDOUS WEATHER OUTLOOK IS FOR PORTIONS OF NORTHWEST
OREGON AND SOUTHWEST WASHINGTON COASTAL WATERS.

.DAY ONE...TODAY AND TONIGHT

WEST SWELL FROM A STRONG STORM OVER THE GULF OF ALASKA WILL
ARRIVE TODAY. EXPECT WEST SWELL BETWEEN 25 TO 30 FT ON THE COASTAL
WATERS FOR LATE TODAY AND CONTINUE TONIGHT.

.DAYS TWO THROUGH SEVEN...SATURDAY THROUGH THURSDAY

WEST SWELL OF 25 TO 30 FT WILL CONTINUE MOVING ON THE COASTAL
WATERS FOR SATURDAY...THEN SLOWLY SUBSIDE SATURDAY NIGHT AND
SUNDAY.

.SPOTTER INFORMATION STATEMENT...

SPOTTER REPORTS ARE NOT LIKELY TO BE NEEDED TODAY.

ORZ001-002-PZZ210-WAZ021-071345-
NORTH OREGON COAST-CENTRAL OREGON COAST-COLUMBIA RIVER BAR-
SOUTH WASHINGTON COAST-
543 AM PST FRI NOV 6 2009

THIS HAZARDOUS WEATHER OUTLOOK IS FOR PORTIONS OF NORTHWEST
OREGON...NORTHWEST OREGON AND SOUTHWEST WASHINGTON COASTAL WATERS
AND SOUTHWEST WASHINGTON.

.DAY ONE...TODAY AND TONIGHT

WEST SWELL FROM A STRONG STORM OVER THE GULF OF ALASKA WILL
ARRIVE TODAY. EXPECT WEST SWELL BETWEEN 25 TO 30 FT TO BEGIN
ROLLING INTO THE COASTAL SURF ZONE LATER TODAY. THIS WILL CREATE
DANGEROUS SURF ZONE CONDITIONS...WHICH WILL LAST THROUGH TONIGHT.
WORST CONDITIONS WILL OCCUR DURING HIGH TIDE AROUND 3 TO 4 PM THIS
AFTERNOON.

.DAYS TWO THROUGH SEVEN...SATURDAY THROUGH THURSDAY

WEST SWELL BETWEEN 25 TO 30 FT WILL CONTINUE POUNDING THE COASTAL
SURF ZONE SATURDAY AND SATURDAY NIGHT....CREATING DANGEROUS SURF
ZONE CONDITIONS. SWELL WILL BEGIN SUBSIDING LATER SATURDAY NIGHT
AND FALL BELOW 20 FEET LATE SUNDAY.

.SPOTTER INFORMATION STATEMENT...

SPOTTER REPORTS ARE NOT LIKELY TO BE NEEDED TODAY.

ORZ011-013-WAZ019-071345-
NORTHERN OREGON CASCADES-CASCADES IN LANE COUNTY-
SOUTH WASHINGTON CASCADES-
543 AM PST FRI NOV 6 2009

THIS HAZARDOUS WEATHER OUTLOOK IS FOR PORTIONS OF NORTHWEST
OREGON AND SOUTHWEST WASHINGTON.

.DAY ONE...TODAY AND TONIGHT

A WINTER WEATHER ADVISORY FOR SNOW REMAINS IN EFFECT TODAY AND
TONIGHT FOR THE CASCADES.

STRONG AND COOL ONSHORE FLOW WILL BRING PERIODS OF MODERATE TO
HEAVY SNOW TO THE CASCADES. THE SNOW LEVEL WILL HOVER BETWEEN
3500 AND 4000 FEET TODAY AND TONIGHT.

AVERAGE SNOW FALL RATES ARE EXPECTED TO RANGE BETWEEN 6 TO 10
INCHES OF SNOW PER 12 HOUR PERIOD TODAY AND TONIGHT.

.DAYS TWO THROUGH SEVEN...SATURDAY THROUGH THURSDAY

THE SNOW LEVEL WILL HOVER AROUND 3000 FEET SATURDAY AND SATURDAY
NIGHT...POSSIBLY DROPPING AS LOW AS 2500 FEET SATURDAY NIGHT.
ADDITIONAL SNOWFALL OF 1 TO 2 FEET ARE POSSIBLE FOR SATURDAY
THROUGH SUNDAY MORNING. WINTER WEATHER ADVISORY FOR SNOW CONTINUES
THROUGH SUNDAY MORNING FOR THE CASCADES.

MORE SNOW IS LIKELY NEXT TUESDAY THROUGH THURSDAY AS MORE COLD AIR
AND SHOWERS ARRIVE. ADDITIONAL SIGNIFICANT SNOWFALL IS EXPECTED AT
THAT TIME.

.SPOTTER INFORMATION STATEMENT...

SPOTTER REPORTS OF SNOWFALL AND OR SNOWFALL RATES ARE ENCOURAGED
TODAY.

ORZ003>010-012-014-WAZ020-022-023-039-040-071345-
COAST RANGE OF NORTHWEST OREGON-
CENTRAL COAST RANGE OF WESTERN OREGON-LOWER COLUMBIA-
GREATER PORTLAND METRO AREA-CENTRAL WILLAMETTE VALLEY-
SOUTH WILLAMETTE VALLEY-WESTERN COLUMBIA RIVER GORGE-
NORTHERN OREGON CASCADE FOOTHILLS-
CASCADE FOOTHILLS IN LANE COUNTY-UPPER HOOD RIVER VALLEY-
WILLAPA HILLS-I-5 CORRIDOR IN COWLITZ COUNTY-
GREATER VANCOUVER AREA-SOUTH WASHINGTON CASCADE FOOTHILLS-
543 AM PST FRI NOV 6 2009

THIS HAZARDOUS WEATHER OUTLOOK IS FOR PORTIONS OF NORTHWEST
OREGON AND SOUTHWEST WASHINGTON.

.DAY ONE...TODAY AND TONIGHT

THE PROBABILITY OF WIDESPREAD HAZARDOUS WEATHER IS LOW.

.DAYS TWO THROUGH SEVEN...SATURDAY THROUGH THURSDAY

THE PROBABILITY OF WIDESPREAD HAZARDOUS WEATHER IS LOW.

.SPOTTER INFORMATION STATEMENT...

SPOTTER REPORTS ARE NOT LIKELY TO BE NEEDED TODAY.