Gale Warning 382, NWS Juneau, AK

SOUTHEAST ALASKA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE JUNEAU AK
355 PM AKST SUN NOV 27 2011

.SHORT TERM...COMPLICATED SHORT RANGE FORECAST IN THE WORKS.
STRONG STORM WILL BE AFFECTING THE AREA STARTING LATE TONIGHT AND
INTO TOMORROW. BRINGING MORE PRECIP AND WIND. THE MAIN FORECAST
CHALLENGE FOR THIS SYSTEM IS HOW FAST AND HOW FAR NORTH THE WARM
ADVECTION AHEAD OF THE FRONT WILL PUSH THE RAIN/SNOW LINE ON
MONDAY. THE VARIOUS SHORT RANGE MODELS ARE NOT AGREEING ON THIS
ISSUE VERY WELL. THE NAM IS THE COLDEST, KEEPING MANY AREAS COLD
ENOUGH THAT MOST OF THE PRECIP FALLS AS SNOW WITH SNOWFALL
AMOUNTS WELL INTO WARNING CRITERIA OVER MOST INNER CHANNEL AREAS.
THE GFS ON THE OTHER HAND IS MUCH WARMER SWITCHING THE SNOW OVER
TO RAIN EARLY ON MONDAY WITH SNOWFALL AMOUNTS NOT EVEN
APPROACHING ADVISORY LEVELS. WITH THE HIGH SPREAD BETWEEN THE
MODELS ON TEMPERATURE AND SNOWFALL DECIDED TO GO WITH A MIDDLE OF
THE ROAD APPROACH. THUS LARGELY LEFT THE CURRENT WINTER WEATHER
HEADLINES ALONE. STILL EXPECTING 3 TO 6 INCHES IN THE ADVISORY
AREAS AND 5 TO 10 INCHES IN THE WARNING AREAS THROUGH MON
AFTERNOON BEFORE THE SNOW TAPERS OFF OR CHANGES TO RAIN.

IN ANY CASE THE MOISTURE WILL BE THERE TO SUPPORT THIS SYSTEM AS
A ATMOSPHERIC RIVER IS FEEDING IT ALL THE WAY FROM 20 DEGREES
NORTH LATITUDE AND A NICE BAROCLINIC LEAF IS FORMING ALONG THE
FRONT IN THE NORTH PACIFIC AS SEEN FROM SATELLITE IMAGES. TPW
VALUES UP TO 25 TO 30 MM WERE MEASURED WITH IN THIS SYSTEM FROM
THE MICROWAVE SENSORS ON THE VARIOUS POLAR SATELLITES AS WELL.
MODELS ARE ALSO SUGGESTING SOME DECENT ISENTROPIC LIFT OVER THE
AREA AS WELL.

WIND WILL ALSO BE PROBLEM AS THIS FRONT COMES THROUGH. GALE FORCE
WINDS ARE EXPECTED ALONG ALL OF THE OUTSIDE WATERS LATE TONIGHT
AND WILL BE DIMINISHING MONDAY. FOR THE INNER CHANNELS, CLARENCE
STRAIT AND SUMNER STRAIT WILL SEE GALE FORCE WINDS AT SOME POINT
MONDAY. MOST OF THE OTHER INNER CHANNELS WILL SEE SMALL CRAFT
WINDS AS THE FRONT MOVES THROUGH. AS FOR THE LAND AREAS, STRONG
WIND HEADLINES ARE UP FOR SITKA, HYDABURG, AND KETCHIKAN ZONES
LATE TONIGHT AND EARLY MON AS A DECENT 65 KT 850 MB JET POUNDS
INTO THE PANHANDLE. I EXPECT GUSTS UP TO 50 MPH IN THE HEADLINED
AREA. BREEZY CONDITIONS ARE EXPECTED FOR THE REST OF THE
PANHANDLE, BUT SOME OCCASIONAL HIGHER WIND GUSTS ARE POSSIBLE AS
THE FRONT PUSHES THROUGH.

SHORT RANGE MODELS DID NOT INITIALIZE IN THE UPPER LEVELS ALL
THAT WELL THIS MORNING. MOST WERE STILL A BIT TOO WEAK WITH THE
STRENGTH OF THE JET COMPARED TO SATELLITE DERIVED WIND VECTORS.
OTHER UPPER LEVEL FEATURES WERE NOT VERY WELL REPRESENTED EITHER.
ON THE OTHER HAND SURFACE INITIALIZATION WAS DECENT. 12Z NAM WAS A
BIT OFF WITH THE SURFACE LOW POSITION NEAR KODIAK ISLAND, BUT ALL
DID OK WITH REPRESENTING THE FRONT. DECIDED ON BLEND OF NAM AND
GFS WITH A SPRINKLING OF OTHER MODELS FOR THE VARIOUS FORECAST
FIELDS. FORECAST CONFIDENCE IS ABOUT AVERAGE DUE TO UNCERTAINTY ON
TEMPERATURE AND SNOWFALL AMOUNTS.

&&

.LONG TERM...EXPECT A CHANGE IN THE LONG WAVE PATTERN BY MID WEEK
AS A STRONG HIGH AMPLITUDE RIDGE BUILDS FROM THE NORTHEAST
PACIFIC AND ACROSS B.C. AND LEAVS THE PANHANDLE UNDER A LONG FETCH
SW FLOW.

FIRST LOW FROM SHORT TERM WILL MOVE ACROSS SOUTHERN YUKON MONDAY
NIGHT LEAVING A MODERATE WESTERLY ACROSS THE GULF OF ALASKA
THROUGH TUESDAY. SURFACE HIGH AND RIDGE ALOFT MOVE INTO THE
EASTERN GULF TUESDAY NIGHT AND TILTS EAST INTO CANADA ON
WEDNESDAY. A STRONG 160 KT JET STREAM RIDES NE ON BACK SIDE OF THE
RIDGE INTO NE GULF WEDNESDAY AND SLOWLY PUSHES ACROSS SOUTHEAST
ALASKA THURSDAY. ANOTHER WAVE FOLLOWS FRIDAY. RIDGE REBUILDS
ACROSS THE EASTERN GULF SATURDAY.

WILL BEGIN THE LONG TERM WITH A MIX OF RAIN AND SNOW BEHIND FIRST
FRONT AND WESTERLY FLOW. DO NOT FORSEE SIGNIFICANT RAIN OR SNOW
AMOUNTS WITH THIS AS ATMO IS STABILIZING. POPS DROP OFF ACROSS
SOUTHERN HALF AS HIGH BUILDS IN MON NIGHT THROUGH WEDNESDAY. THERE
WILL LIKELY BE AREAS OF FOG. HYDER COULD GET BACK INTO COLD
DRAINAGE FROM INTERIOR WITH SUBFREEZING TEMPS. NORTHERN AREAS
STILL IN ONSHORE FLOW AND WILL KEEP A CHANCE OF MIXED RAIN AND
SNOW.

AS RIDGE SHIFTS EAST ON WEDNESDAY...A 160 KT SSW JET STREAM MOVES
TO PAYA WITH HEAVY RAIN. SOLID SLY GALES MOVE INTO THE EASTERN
GULF FROM THE WEST ON WED AND WILL BRING WARMER TEMPS TO THE AREA.
GFS IS ADVERTISING 4 TO 7 INCHES OF RAIN FOR YAKUTAT ZONE. THIS
WILL FALL ON TOP OF AN UNUSUALLY DEEP NOVEMBER SNOW PACK AND WILL
INCREASE SNOW LOADS AND EVENTUALLY THE THREAT OF URBAN TYPE
FLOODING WHERE STORM DRAINS AND DITCHES ARE BURIED.

THE RAIN SPREADS ACROSS SOUTHEAST ALASKA WEDNESDAY NIGHT AND
THURSDAY WITH RAIN OR POSSIBLY SNOW CHANGING TO RAIN IN THE FAR
NORTH. RAINFALL AMOUNTS WILL BE MODERATELY HEAVY AND WILL ALSO HAVE
SNOW LOAD AND URBAN FLOOD ISSUES AS WELL AS INCREASED AVALANCHE
DANGER, WINDS ON THE INNER CHANNELS WILL INCREASE TO SMCR TO GALES
AND A STRONG WIND FOR CLARENCE AND SOUTHERN AND COASTAL ZONES.
SNOW LEVEL ARE EXPECTED TO CLIMB TO 3K IN THE NORTH AND 6 K SOUTH.

A SECOND WAVE MOVES ACROSS NORTHERN GULF FRIDAY BUT STILL HAVE LOW
UNCERTAINTY IN POSITION TIMING AND INTENSITY. COULD SEE A QUICK
SHOT OF SNOW AHEAD OF THIS SYSTEM BUT IT WILL GO BACK TO ALL RAIN
WITH ONSHORE WAA.

USED A NAM GFS BLEND THROUGH 00Z THURSDAY THEN HPC AND A GFS/EC
BLEND BEYOND.

.AJK WATCHES/WARNINGS/ADVISORIES...
PUBLIC...WINTER WEATHER ADVISORY FROM 9 PM THIS EVENING TO 3 PM AKST
     MONDAY FOR AKZ018-020-021-024>026.
         STRONG WIND FROM MIDNIGHT AKST TONIGHT THROUGH LATE TONIGHT FOR
     AKZ027.
         WINTER STORM WARNING FROM 9 PM THIS EVENING TO 3 PM AKST MONDAY
     FOR AKZ017-019-022.
         STRONG WIND FROM 9 PM THIS EVENING TO 3 AM AKST MONDAY FOR
     AKZ023.
         STRONG WIND FROM 3 AM AKST MONDAY THROUGH MONDAY MORNING FOR
     AKZ028.
MARINE...GALE WARNING FOR PKZ022-035-036-041>043-051-052.
         SMALL CRAFT ADVISORY FOR PKZ011>013-021-031>034-053.

&&

EAL/MM

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE JUNEAU AK
230 PM AKST SUN NOV 27 2011

AKZ017>029-282330-
CAPE FAIRWEATHER TO CAPE SUCKLING COASTAL AREA-
TAIYA INLET AND KLONDIKE HIGHWAY-HAINES BOROUGH AND LYNN CANAL-
GLACIER BAY-EASTERN CHICHAGOF ISLAND-
SALISBURY SOUND TO CAPE FAIRWEATHER COASTAL AREA-
CAPE DECISION TO SALISBURY SOUND COASTAL AREA-
EASTERN BARANOF ISLAND AND SOUTHERN ADMIRALTY ISLAND-
JUNEAU BOROUGH AND NORTHERN ADMIRALTY ISLAND-
INNER CHANNELS FROM KUPREANOF ISLAND TO ETOLIN ISLAND-
DIXON ENTRANCE TO CAPE DECISION COASTAL AREA-
SOUTHERN INNER CHANNELS-MISTY FJORDS-
INCLUDING THE CITIES OF...YAKUTAT...SKAGWAY...HAINES...GUSTAVUS...
HOONAH...ELFIN COVE...PELICAN...SITKA...PORT ALEXANDER...ANGOON...
JUNEAU...PETERSBURG...WRANGELL...KAKE...CRAIG...KLAWOCK...
KETCHIKAN...METLAKATLA...HYDER
230 PM AKST SUN NOV 27 2011

...CHANGING WEATHER PATTERN FOR THE ALASKAN PANHANDLE MID WEEK...

A STRONG AREA OF HIGH PRESSURE FORECAST TO BUILD OVER THE NORTHEAST
PACIFIC. THIS WILL SEND A WARM AND VERY WET WEATHER SYSTEM INTO THE
EASTERN GULF WEDNESDAY AND ACROSS SOUTHEAST ALASKA BY THURSDAY. THIS WILL
BRING THE POTENTIAL FOR HEAVY RAIN TO AREA WEDNESDAY AND THURSDAY.

THE HEAVY RAIN WILL FALL ON AN UNUSUALLY HIGH NOVEMBER SNOW PACK
WHICH WILL INITIALLY RESULT IN INCREASED SNOW LOADS ON BUILDINGS,
ESPECIALLY FOR THE YAKUTAT AND HAINES AREAS. IT WILL ALSO INCREASE
THE AVALANCHE DANGER.

AS TEMPERATURES CONTINUE TO WARM AND THE SNOW MELTS, THERE WILL BE
THE POTENTIAL FOR URBAN TYPE FLOODING WHERE DITCHES AND STORM
DRAINS ARE BLOCKED BY SNOW.

PERSONS ACROSS SOUTHEAST ALASKA CAN PREPARE FOR THIS EVENT BY
REMOVING SNOW FROM STRUCTURES AND OBJECTS THAT CAN BE DAMAGED BY
THE EXCESSIVE WEIGHT OF THE WET SNOW. STORM DRAINS SHOULD BE CLEARED
OF SNOW.

SPECIAL WEATHER STATEMENT...CORRECTED
NATIONAL WEATHER SERVICE JUNEAU AK
244 PM AKST SUN NOV 27 2011

AKZ017>029-282345-
CAPE FAIRWEATHER TO CAPE SUCKLING COASTAL AREA-
TAIYA INLET AND KLONDIKE HIGHWAY-HAINES BOROUGH AND LYNN CANAL-
GLACIER BAY-EASTERN CHICHAGOF ISLAND-
SALISBURY SOUND TO CAPE FAIRWEATHER COASTAL AREA-
CAPE DECISION TO SALISBURY SOUND COASTAL AREA-
EASTERN BARANOF ISLAND AND SOUTHERN ADMIRALTY ISLAND-
JUNEAU BOROUGH AND NORTHERN ADMIRALTY ISLAND-
INNER CHANNELS FROM KUPREANOF ISLAND TO ETOLIN ISLAND-
DIXON ENTRANCE TO CAPE DECISION COASTAL AREA-
SOUTHERN INNER CHANNELS-MISTY FJORDS-
INCLUDING THE CITIES OF...YAKUTAT...SKAGWAY...HAINES...GUSTAVUS...
HOONAH...ELFIN COVE...PELICAN...SITKA...PORT ALEXANDER...ANGOON...
JUNEAU...PETERSBURG...WRANGELL...KAKE...CRAIG...KLAWOCK...
KETCHIKAN...METLAKATLA...HYDER
244 PM AKST SUN NOV 27 2011

...CHANGING WEATHER PATTERN FOR THE ALASKAN PANHANDLE MID WEEK...

A STRONG AREA OF HIGH PRESSURE IS FORECAST TO BUILD OVER THE
NORTHEAST PACIFIC. THIS WILL SEND A WARM AND VERY WET WEATHER
SYSTEM INTO THE EASTERN GULF WEDNESDAY AND ACROSS SOUTHEAST ALASKA
BY THURSDAY. THIS WILL BRING THE POTENTIAL FOR HEAVY RAIN TO AREA
WEDNESDAY AND THURSDAY.

THE HEAVY RAIN WILL FALL ON AN UNUSUALLY HIGH NOVEMBER SNOW PACK
WHICH WILL INITIALLY RESULT IN INCREASED SNOW LOADS ON BUILDINGS,
ESPECIALLY FOR THE YAKUTAT AND HAINES AREAS. IT WILL ALSO INCREASE
THE AVALANCHE DANGER.

AS TEMPERATURES CONTINUE TO WARM AND THE SNOW MELTS, THERE WILL BE
THE POTENTIAL FOR URBAN TYPE FLOODING WHERE DITCHES AND STORM
DRAINS ARE BLOCKED BY SNOW.

PERSONS ACROSS SOUTHEAST ALASKA CAN PREPARE FOR THIS EVENT BY
REMOVING SNOW FROM STRUCTURES AND OBJECTS THAT CAN BE DAMAGED BY
THE EXCESSIVE WEIGHT OF THE WET SNOW. STORM DRAINS SHOULD BE CLEARED
OF SNOW.