High Wind in Alaska, February 20 to 21, 2009

Name: High Wind in Alaska, February 20 to 21, 2009
Start: 2009-02-20T19:40
End: 2009-02-21T06:00
Location: Alaska

February 20 to 21, 2009 · NWS AFC · 2 events in 2 counties and zones

Strong high pressure over interior Alaska combined with low pressure in the Gulf of Alaska produced a strong pressure gradient. High wind blew out of the Copper River Delta and in Thompson Pass.

The toll

Deaths: 0
Injuries: 0
Property damage: None recorded
Crop damage: None recorded
Events: 2

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.

What happened

The episode as NWS AFC wrote it up.

Strong high pressure over interior Alaska combined with low pressure in the Gulf of Alaska produced a strong pressure gradient. High wind blew out of the Copper River Delta and in Thompson Pass.

What forecasters said that day

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 Anchorage, AK wrote its last area forecast discussion before the first event at Feb 20, 5:00 PM AKST, 2 hours 40 minutes earlier.

Area forecast discussion, Feb 20, 5:00 PM AKST, 2 hours 40 minutes before

AREA FORECAST DISCUSSION
SOUTHCENTRAL AND SOUTHWEST ALASKA
500 PM AKST FRI FEB 20 2009

.MODEL DISCUSSION...
MODELS ARE IN VERY GOOD AGREEMENT THROUGH SUNDAY NIGHT AND ARE
CONSISTENT WITH PREVIOUS RUNS. WINDS IN THE FIRST 12 HOURS OF THE GFS
HAVE MATCH OBSERVED WINDS OVER THE CENTRAL ALEUTIANS BETTER THAN THE
NAM MODEL, WHICH APPEAR TO BE A LITTLE TOO WEAK. I WOULD SUGGEST
GOING WITH THE GFS OVER THE BERING SEA FOR TONIGHT, OTHERWISE, IT
YOUR CHOICE.

.ANALYSIS AND UPPER LEVELS...
THE UPPER TROUGH MOVING THROUGH SOUTHCENTRAL ALASKA WILL HAVE LITTLE
AFFECT DUE TO THE DRYNESS OF THE ATMOSPHERE BEHIND THE FRONT. THE
UPPER RIDGE OVER THE EASTERN BERING SEA CONTINUES TO BUILD.

AT THE SURFACE...THE COLD FRONT MOVING THROUGH THE COPPER RIVER BASIN
WILL MOVE INTO THE YUKON TONIGHT. NORTH WINDS WILL INCREASE OVER
SOUTHCENTRAL THROUGH THIS EVENING AND WILL BE ESPECIALLY STRONG
THROUGH MOUNTAIN GAPS ALONG THE CENTRAL GULF COAST. AN INTENSE STORM
MOVING THROUGH THE WESTERN ALEUTIANS HAS PRODUCED WIND GUSTS IN
EXCESS OF 80 MPH THROUGH THE CENTRAL ALEUTIANS.

.SHORT TERM FORECAST...
UPPER AIR...THE UPPER TROUGH OVER THE COPPER RIVER BASIN WILL MOVE
INTO THE YUKON TERRITORY SATURDAY. THE UPPER RIDGE OVER THE EASTERN
BERING SEA WILL BECOME NEARLY STATIONARY OVER MAINLAND ALASKA
SATURDAY AND WILL SIGNIFICANTLY WEAKEN ANY FRONT APPROACHING THE WEST
COAST OF ALASKA THROUGH THE WEEKEND.

AT THE SURFACE...
SOUTHCENTRAL ALASKA AND THE GULF...A FEW SNOW SHOWERS OVER THE
INTERIOR WILL PERSIST THROUGH TONIGHT WITH THE PASSAGE OF THE UPPER
TROUGH. OTHERWISE, THE SKIES WILL GENERALLY CLEAR FROM THE WEST
THROUGH TONIGHT AND WILL REMAIN MOSTLY SUNNY THROUGH THE WEEKEND.
SOME MID TO HIGH LEVEL CLOUDS WILL MOVE INTO THE SUSITNA VALLEY AS A
WEAK UPPER SHORT WAVE TROUGH RIPPLES THROUGH THE RIDGE.

SOUTHWEST ALASKA...THE WEATHER FRONT ASSOCIATED WITH THE STORM OVER
THE WESTERN ALEUTIANS WILL MOVE EAST INTO THE KUSKOKWIM DELTA COAST
SATURDAY AFTERNOON THEN WILL DISSIPATE OVER THE SOUTHWEST INTERIOR
SATURDAY NIGHT. THE AREA OF STRONG WINDS AHEAD OF THE FRONT WILL
PRODUCE AREAS OF BLOWING SNOW ALONG THE COAST SATURDAY MORNING WHICH
WILL CONTINUE THROUGH SATURDAY EVENING. SNOW WILL MOVE INTO THE
KUSKOKWIM DELTA BY SATURDAY AFTERNOON AND WILL SPREAD INTO WESTERN
BRISTOL BAY AND WESTERN KUSKOKWIM VALLEY SATURDAY NIGHT BEFORE
CHANGING TO SNOW SHOWERS SUNDAY.

BERING SEA...THE STRONG STORM OVER THE WESTERN ALEUTIANS WILL
CONTINUE TO MOVE NORTH AND WEAKEN THROUGH TONIGHT THEN MOVE INTO
SIBERIA SATURDAY. THE ASSOCIATED WEATHER FRONT OVER THE SOUTHWEST
BERING AND CENTRAL ALEUTIANS WILL MOVE NORTHEAST INTO WESTERN ALASKA
SATURDAY. THE AREA OF STORM TO HURRICANE FORCE WINDS AHEAD OF THE
FRONT WILL WEAKEN TO STORM FORCE WINDS AS IT MOVES THROUGH THE
PRIBILOFS LATE TONIGHT AND WILL CONTINUE TO WEAKEN TO GALES AS IT
APPROACHES THE WEST COAST. A SECOND STORM DEVELOPING WEST OF HOKKAIDO
WILL MOVE NORTHEAST INTO THE NORTHERN BERING SEA BY SUNDAY AFTERNOON.

STORM FORCE WILL WILL MOVE INTO THE WESTERN ALEUTIANS SATURDAY
AFTERNOON THEN WEAKEN TO GALES OVER THE CENTRAL ALEUTIANS SATURDAY
NIGHT.

.LONG TERM FORECAST...
THE UPPER RIDGE OVER MAINLAND ALASKA WILL BEGIN TO DRIFT EAST
SATURDAY NIGHT AND WILL MOVE INTO THE YUKON TERRITORY AND SOUTHEAST
ALASKA TUESDAY NIGHT. STORM COMING OFF THE NORTH PACIFIC WILL TRACK
THROUGH THE CENTRAL BERING MONDAY AND TUESDAY.

.AER/ALU...WATCH/WARNING SUMMARY
PUBLIC...BLIZZARD WATCH FOR 151 SATURDAY.
MARINE...STORM...170, 172, 179
         GALE...120, 121, 129, 130, 132, 155, 165, 175, 176, 180
FIRE WEATHER...NONE.

NM FEB 09

Event by event

2 high wind. Local standard time, as filed.

High Wind, Nern P.W. Snd

When: February 20, 7:40 PM AKST to February 21, 6:00 AM AKST
Where: Nern P.W. Snd forecast zone
Measured: 70 kt (81 mph) measured gust
Reported by: Department of Highways

Thompson Pass RWIS reported 80 mph gust.

High Wind, Sern P.W. Snd

When: February 20, 7:40 PM AKST to February 21, 6:00 AM AKST
Where: Sern P.W. Snd forecast zone
Measured: 70 kt (81 mph) estimated gust
Reported by: NWS Employee

Estimated wind gust based upon Thompson Pass wind speed and synoptic pattern.

What these are

High Wind: Sustained non-thunderstorm winds of 40 mph or more for an hour, or gusts of 58 mph or more.

After NWS Directive 10-1605, the rules offices file Storm Data by.

The same day elsewhere

Every storm in Alaska in 2009 Every state in 2009 This day in weather history Warnings in Alaska, February 2009

Sources

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: 147410, 147413.