A Pacific frontal system brought heavy snow to the North Cascades at Mt Baker.
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 SEW wrote it up.
A Pacific frontal system brought heavy snow to the North Cascades at Mt Baker.
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 Seattle, WA wrote its last area forecast discussion before the first event at Nov 20, 9:15 PM PST, 3 hours 45 minutes earlier.
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SEATTLE WA
915 PM PST TUE NOV 20 2012
.SYNOPSIS...THE NEXT BATCH OF SHOWERS AND ISOLATED THUNDERSTORMS
WILL MOVE THROUGH WESTERN WASHINGTON LATER TONIGHT THROUGH WEDNESDAY
MORNING. IT WILL BECOME BLUSTERY AGAIN...ESPECIALLY AROUND DAYBREAK
WEDNESDAY. THE SHOWERS WILL END WEDNESDAY EVENING AS HIGH PRESSURE
BUILDS OVER THE REGION. A WARM FRONT WILL BRUSH THE NORTH COAST
THURSDAY. A COLD FRONT WILL MOVE THROUGH WESTERN WASHINGTON FRIDAY.
A DRIER WEATHER PATTERN WILL SET UP OVER THE WEEKEND.
&&
.SHORT TERM...THE NEXT INSTANT OCCLUSION...OR COMMA CLOUD...WILL
MOVE THROUGH WESTERN WA LATE TONIGHT. ANOTHER ROUND OF SHOWERS AND
ISOLATED THUNDERSTORMS WITH BLUSTERY WINDS WILL SWEEP THROUGH
WESTERN WA WED MORNING. WITH COOLER AIR ALOFT AND STRONGER WESTERLY
FLOW THE SNOW SHOWERS IN THE MOUNTAINS WILL FALL TO A LOWER
ELEVATIONS AND BE HEAVY AT TIMES...AND A WINTER WEATHER ADVISORY FOR
THE MTNS WILL BE ISSUED SHORTLY. THE SHOWERS WILL DECREASE WED
AFTERNOON AND EVENING...THEN WED NITE AND THU SHOULD BE DRY. A WARM
FRONT WILL BRUSH THE AREA THU BUT THE NAM SHOWS ONLY A LITTLE LIGHT
RAIN BRUSHING THE NORTH COAST AND ALL THAT PRECIP STAYS UP IN B.C.
THU. THE ASSOCIATED COLD FRONT FROM THAT SYSTEM WILL REACH WESTERN
WA FRI. THE LOW PRESSURE SYSTEM THAT SPINS UP WELL OFFSHORE WED WILL
BE ONE TO WATCH ON SATELLITE IMAGERY...ALTHOUGH IT STAYS WELL
OFFSHORE UNTIL IT WEAKENS THE FORECAST MIN PRES BY THE 12Z ECMWF WAS
A 956MB LOW NEAR 52N 142W THU AFTERNOON AFTER GETTING ABOUT 36HRS
OFF EXPLOSIVE CYCLOGENESIS...GOOD THING THAT ONE IS FAR OFFSHORE. 19
.LONG TERM...PREVIOUS DISCUSSION...MODELS ARE GENERALLY SHOWING A
TEMPORARY PATTERN CHANGE STARTING SATURDAY AS LONG WAVE RIDGING
AMPLIFIES ALONG ABOUT 140W. THE OFFSHORE RIDGING FORCES AN UPPER LOW
OVER THE GULF OF ALASKA TO WEAKEN AND SHIFT SOUTHEAST INTO
WASHINGTON SATURDAY AND SUNDAY GIVING MAINLY WET WEATHER TO THE AREA
TEMPERATURES NEAR OR A LITTLE BELOW AVERAGE.
STARTING ON MONDAY MODEL SOLUTIONS DIVERGE. MOST RECENT GFS AND
CANADIAN SOLUTIONS SHOW THE RIDGING ALONG ABOUT 140W AMPLIFYING
ENOUGH TO ALLOW SOME MODIFIED CANADIAN AIR TO FILTER INTO THE
NORTHERN PORTIONS OF THE STATE. THE LATEST ECMWF IS LESS AGGRESSIVE
WITH THE OFFSHORE RIDGING AND KEEPS COLD AIR BOTTLED UP NORTH OF THE
CANADIAN COASTAL TERRAIN...FOLLOWED BY MORE RIDGING BY THE END OF
THE PERIOD. THIS DIFFERS FROM THE 00Z ECMWF AND ITS GUIDANCE. GIVEN
ALL THE DIFFERENCES AND THE LARGE ENSEMBLE SPREAD...A BROAD BRUSH
FORECAST WITH CHANCE POPS...HIGHEST SOUTH...AND TEMPERATURES ONLY A
FEW DEGREES BELOW SEASONAL AVERAGE WERE USED FOR THE FIRST HALF ON
NEXT WEEK. ALBRECHT
&&
.HYDROLOGY...THE NEXT WEATHER IMPULSE WILL BRING ANOTHER ROUND OF
SHOWERS AND BLUSTERY WEATHER LATER TONIGHT AND WED MORNING...BUT
THIS ADDITIONAL RAINFALL IS NOT EXPECTED TO BE HYDROLOGICALLY
SIGNIFICANT.
THE OBSERVATIONS AND LATEST FORECAST FOR THE CHEHALIS AT CENTRALIA
SHOWS THE RIVER CRESTING TONIGHT AROUND 64.2 FEET...BELOW THE FLOOD
STAGE OF 65 FEET...SO WILL BE ABLE TO DROP THE FLOOD WARNING FOR
THAT SPOT AND LEWIS COUNTY...THE NEXT FLOOD STATEMENT FOR THE
CHEHALIS SHOULD BE OUT BY 10PM.
THE HIGH WATER ON THE CHEHALIS IN THURSTON COUNTY: THE CHEHALIS AT
GRAND MOUND WILL REMAIN ABOVE FLOOD STAGE PROBABLY UNTIL EARLY WED
AFTERNOON. FURTHER DOWNSTREAM...THE FORECAST AT PORTER IS A VERY
SLOW RISE TO THE CREST WED AFTERNOON OR EVENING RIGHT AROUND FLOOD
STAGE.
THE SKOKOMISH RIVER WILL GRADUALLY FALL...BUT STILL ABOVE FLOOD
STAGE TONIGHT THEN DROPPING BELOW THE MARK WED MORNING.
THE NEXT WETTER AND WARMER FRONT WILL MOVE ACROSS THE AREA THURSDAY
NIGHT AND FRIDAY....BUT WITH THE BREAK IN THE PRECIP WED NIGHT AND
THU AND THE PROGRESSIVE NATURE OF THAT FRONT...FLOODING IS NOT
EXPECTED. 19
&&
AVIATION...A LOW PRES CENTER OFF THE NRN ORE COAST THIS EVNG WILL
MOVE NE INTO SW WA AND ACROSS THE SOUTH END OF PUGET SOUND
OVERNIGHT. HAS BEEN OCCASIONAL LIGHTNING NEAR THE LOW CENTER
OFFSHORE IN RECENT HOURS. EXTRAPOLATING THE MOVEMENT OF THE NORTHERN
EXTENT OF LIGHTNING WOULD PLACE IT NEAR KOLM AROUND 09Z...AS IT
MOVES NE NEAR 35 KT. AFTER THE LOW CENTER PASSES...A MOIST AND
UNSTABLE AIR MASS WILL PERSIST THROUGH WED...LEADING TO A SHOWERY
PATTERN. DEVELOPMENT OF A PUGET SOUND CONVERGENCE ZONE IS POSSIBLE
ON WED AFTN.
KSEA...LOOKING AT A RELATIVE LULL IN SHOWER ACTIVITY UNTIL ABOUT
09Z. ARND 09Z...LOOKING AT A FEW HOURS OF HEAVY SHOWER ACTIVITY
ARRIVING...WITH THE POSSIBILITY OF EMBEDDED LIGHTNING FROM 09Z-14Z.
CONFIDENCE NOT HIGH ENOUGH YET TO INCLUDE IN TAF...BUT WOULD INCLUDE
THUNDER IN THE 09Z TAF UPDATE IF LIGHTNING IS OBSERVED UPSTREAM OVER
THE SOUTH SOUND. LOOK FOR A FEW HOURS OF SFC WIND GUSTS TO NEAR 30
KT...CENTERED ARND 15Z. FROM WED 18Z-THU 03Z...A MORE RANDOM SHOWERY
REGIME WILL BE IN PLACE...BEFORE THE AIR MASS DRIES FROM ALOFT ON
WED EVNG. HANER
&&
.MARINE...A 1000 MB LOW IS EXPECTED TO TRAVEL FROM NEAR ASTORIA
AROUND 1 AM TO THE SOUTH SOUND AROUND 4 AM...THEN ON TO THE NORTH
CASCADES AROUND 7 AM. ISOLATED LIGHTNING IS POSSIBLE OVERNIGHT NEAR
THE TRACK OF THE LOW CENTER. ALONG AND SOUTH OF THE LOW TRACK...SW
WINDS WILL PICK UP QUICKLY AFTER THE PASSAGE OF THE LOW CENTER. AS
THE LOW MOVES INTO SOUTH-CENTRAL B.C. WED AFTN...LOOK FOR A SURGE OF
SMALL CRAFT WESTERLIES OVER THE COASTAL WATERS AND THROUGH THE
STRAIT OF JDF.
WEAK HIGH PRESSURE RIDGING WILL MOVE ACROSS THE WATERS ON WED NIGHT
FOR A MORE TRANQUIL PERIOD. ON THANKSGIVING DAY...A POWERFUL 960-965
MB LOW WILL MOVE INTO THE SE GULF OF ALASKA. THIS WILL INCREASE SE
GRADIENTS AND BRING GALE-FORCE SOUTHEASTERLIES TO THE COASTAL WATERS
AND THE WEST ENTRANCE FROM THU AFTN THROUGH THU NIGHT. A TRAILING
COLD FRONT WILL SLIP SOUTH THROUGH THE WATERS ON FRI. HIGH PRES WILL
BUILD IN BEHIND THE FRONT FOR A TRANQUIL WEEKEND.
HANER
&&
.SEW WATCHES/WARNINGS/ADVISORIES...
WA...FLOOD WARNINGS REMAIN IN EFFECT FOR PARTS OF THE CWA.
WINTER WEATHER ADVISORY FOR THE CASCADES AND OLYMPICS WED.
PZ...SMALL CRAFT ADVISORIES ARE IN EFFECT FOR ALL WATERS.
SMALL CRAFT ADVISORY FOR ROUGH GRAYS HARBOR BAR CONDITIONS
UNTIL 3 PM PST WEDNESDAY.1 heavy snow. Local standard time, as filed.
USFS NWAC station at Mt Baker measured 12 inches snow in 12 hours ending 1 pm Nov 21, and 20 inches total for the event.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in Washington in 2012Every state in 2012This day in weather historyWarnings in Washington, November 2012
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: 421777.